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13,200 | Electrocardiographic artefacts mimicking atrial tachycardia resulted in unnecessary diagnostic and therapeutic measures. | Electrocardiographic (ECG) artefacts may closely simulate both supraventricular and ventricular tachycardias. We describe a case initially diagnosed as rapid atrial fibrillation, based on 12-lead surface ECG (especially the limb leads) and monitor tracing. The arrhythmia was resistant to beta blockers. Because of the at times apparently regular rhythm, an esophageal ECG recording was performed, and adenosine was administered. When the presumed atrial fibrillation terminated after sodium pentothal was administered while preparing for electrical cardioversion, the oesophageal ECG recordings and the ECGs during adenosine administration were reviewed. An ECG artefact diagnosis was suspected, and then confirmed, during relapse of the "arrhythmia," with simple palpation of the radial pulse and cardiac auscultation. |
13,201 | Trial watch: Cardiac glycosides and cancer therapy. | Cardiac glycosides (CGs) are natural compounds sharing the ability to operate as potent inhibitors of the plasma membrane Na<sup>+</sup>/K<sup>+</sup>-ATPase, hence promoting-via an indirect mechanism-the intracellular accumulation of Ca<sup>2+</sup> ions. In cardiomyocytes, increased intracellular Ca<sup>2+</sup> concentrations exert prominent positive inotropic effects, that is, they increase myocardial contractility. Owing to this feature, two CGs, namely digoxin and digitoxin, have extensively been used in the past for the treatment of several cardiac conditions, including distinct types of arrhythmia as well as contractility disorders. Nowadays, digoxin is approved by the FDA and indicated for the treatment of congestive heart failure, atrial fibrillation and atrial flutter with rapid ventricular response, whereas the use of digitoxin has been discontinued in several Western countries. Recently, CGs have been suggested to exert potent antineoplastic effects, notably as they appear to increase the immunogenicity of dying cancer cells. In this Trial Watch, we summarize the mechanisms that underpin the unsuspected anticancer potential of CGs and discuss the progress of clinical studies that have evaluated/are evaluating the safety and efficacy of CGs for oncological indications. |
13,202 | Atrial fibrillation and outcomes in heart failure with preserved versus reduced left ventricular ejection fraction. | Atrial fibrillation (AF) and heart failure (HF) are 2 of the most common cardiovascular conditions nationally and AF frequently complicates HF. We examined how AF has impacts on adverse outcomes in HF-PEF versus HF-REF within a large, contemporary cohort.</AbstractText>We identified all adults diagnosed with HF-PEF or HF-REF based on hospital discharge and ambulatory visit diagnoses and relevant imaging results for 2005-2008 from 4 health plans in the Cardiovascular Research Network. Data on demographic features, diagnoses, procedures, outpatient pharmacy use, and laboratory results were ascertained from health plan databases. Hospitalizations for HF, stroke, and any reason were identified from hospital discharge and billing claims databases. Deaths were ascertained from health plan and state death files. Among 23 644 patients with HF, 11 429 (48.3%) had documented AF (9081 preexisting, 2348 incident). Compared with patients who did not have AF, patients with AF had higher adjusted rates of ischemic stroke (hazard ratio [HR] 2.47 for incident AF; HR 1.57 for preexisting AF), hospitalization for HF (HR 2.00 for incident AF; HR 1.22 for preexisting AF), all-cause hospitalization (HR 1.45 for incident AF; HR 1.15 for preexisting AF), and death (incident AF HR 1.67; preexisting AF HR 1.13). The associations of AF with these outcomes were similar for HF-PEF and HF-REF, with the exception of ischemic stroke.</AbstractText>AF is a potent risk factor for adverse outcomes in patients with HF-PEF or HF-REF. Effective interventions are needed to improve the prognosis of these high-risk patients.</AbstractText> |
13,203 | Human epicardial adipose tissue induces fibrosis of the atrial myocardium through the secretion of adipo-fibrokines.<Pagination><StartPage>795</StartPage><EndPage>805a</EndPage><MedlinePgn>795-805a</MedlinePgn></Pagination><ELocationID EIdType="doi" ValidYN="Y">10.1093/eurheartj/eht099</ELocationID><Abstract><AbstractText Label="AIMS" NlmCategory="OBJECTIVE">Recent studies have reported a relationship between the abundance of epicardial adipose tissue (EAT) and the risk of cardiovascular diseases including atrial fibrillation (AF). However, the underlying mechanisms are unknown. The aim of this study was to examine the effects of the secretome of human EAT on the histological properties of the myocardium.</AbstractText><AbstractText Label="METHODS AND RESULTS" NlmCategory="RESULTS">Samples of EAT and subcutaneous adipose (SAT), obtained from 39 patients undergoing coronary bypass surgery, were analysed and tested in an organo-culture model of rat atria to evaluate the fibrotic properties of human fat depots. The EAT secretome induced global fibrosis (interstitial and peripheral) of rat atria in organo-culture conditions. Activin A was highly expressed in EAT compared with SAT and promoted atrial fibrosis, an effect blocked using neutralizing antibody. In addition, Activin A levels were enhanced in patients with low left-ventricular function. In sections of human atrial and ventricular myocardium, adipose and myocardial tissues were in close contact, together with fibrosis.</AbstractText><AbstractText Label="CONCLUSION" NlmCategory="CONCLUSIONS">This study provides the first evidence that the secretome from EAT promotes myocardial fibrosis through the secretion of adipo-fibrokines such as Activin A.</AbstractText><CopyrightInformation>Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.</CopyrightInformation></Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Venteclef</LastName><ForeName>Nicolas</ForeName><Initials>N</Initials><AffiliationInfo><Affiliation>Institute of Cardiometabolism and Nutrition, Paris, France INSERM, UMR_S 872, Team 7 Nutriomique, Paris, France Université Pierre et Marie Curie-Paris 6, Cordeliers Research Center, Paris, France.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Guglielmi</LastName><ForeName>Valeria</ForeName><Initials>V</Initials><AffiliationInfo><Affiliation>Institute of Cardiometabolism and Nutrition, Paris, France INSERM, UMR_S 872, Team 7 Nutriomique, Paris, France Université Pierre et Marie Curie-Paris 6, Cordeliers Research Center, Paris, France.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Balse</LastName><ForeName>Elise</ForeName><Initials>E</Initials><AffiliationInfo><Affiliation>Institute of Cardiometabolism and Nutrition, Paris, France Université Pierre et Marie Curie-Paris 6, Cordeliers Research Center, Paris, France Université Pierre et Marie Curie-Paris 6, INSERM UMR_S956, Paris, France.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Gaborit</LastName><ForeName>Bénédicte</ForeName><Initials>B</Initials><AffiliationInfo><Affiliation>Institute of Cardiometabolism and Nutrition, Paris, France INSERM, UMR_S 872, Team 7 Nutriomique, Paris, France Université Pierre et Marie Curie-Paris 6, Cordeliers Research Center, Paris, France Heart and metabolism division, Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Paris Faculté de Médecine, INSERM NORT UMR 1062, INRA1260, Aix Marseille Université, Marseille, France.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Cotillard</LastName><ForeName>Aurélie</ForeName><Initials>A</Initials><AffiliationInfo><Affiliation>Institute of Cardiometabolism and Nutrition, Paris, France INSERM, UMR_S 872, Team 7 Nutriomique, Paris, France Université Pierre et Marie Curie-Paris 6, Cordeliers Research Center, Paris, France.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Atassi</LastName><ForeName>Fabrice</ForeName><Initials>F</Initials><AffiliationInfo><Affiliation>Institute of Cardiometabolism and Nutrition, Paris, France Université Pierre et Marie Curie-Paris 6, Cordeliers Research Center, Paris, France Université Pierre et Marie Curie-Paris 6, INSERM UMR_S956, Paris, France.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Amour</LastName><ForeName>Julien</ForeName><Initials>J</Initials><AffiliationInfo><Affiliation>Institute of Cardiometabolism and Nutrition, Paris, France Heart and metabolism division, Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Paris.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Leprince</LastName><ForeName>Pascal</ForeName><Initials>P</Initials><AffiliationInfo><Affiliation>Institute of Cardiometabolism and Nutrition, Paris, France Heart and metabolism division, Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Paris.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Dutour</LastName><ForeName>Anne</ForeName><Initials>A</Initials><AffiliationInfo><Affiliation>Faculté de Médecine, INSERM NORT UMR 1062, INRA1260, Aix Marseille Université, Marseille, France.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Clément</LastName><ForeName>Karine</ForeName><Initials>K</Initials><AffiliationInfo><Affiliation>Institute of Cardiometabolism and Nutrition, Paris, France INSERM, UMR_S 872, Team 7 Nutriomique, Paris, France Université Pierre et Marie Curie-Paris 6, Cordeliers Research Center, Paris, France Heart and metabolism division, Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Paris stephane.hatem@upmc.fr karine.clement@psl.aphp.fr.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Hatem</LastName><ForeName>Stéphane N</ForeName><Initials>SN</Initials><AffiliationInfo><Affiliation>Institute of Cardiometabolism and Nutrition, Paris, France Université Pierre et Marie Curie-Paris 6, Cordeliers Research Center, Paris, France Université Pierre et Marie Curie-Paris 6, INSERM UMR_S956, Paris, France Heart and metabolism division, Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Paris stephane.hatem@upmc.fr karine.clement@psl.aphp.fr.</Affiliation></AffiliationInfo></Author></AuthorList><Language>eng</Language><PublicationTypeList><PublicationType UI="D016428">Journal Article</PublicationType><PublicationType UI="D013485">Research Support, Non-U.S. Gov't</PublicationType></PublicationTypeList><ArticleDate DateType="Electronic"><Year>2013</Year><Month>03</Month><Day>22</Day></ArticleDate></Article><MedlineJournalInfo><Country>England</Country><MedlineTA>Eur Heart J</MedlineTA><NlmUniqueID>8006263</NlmUniqueID><ISSNLinking>0195-668X</ISSNLinking></MedlineJournalInfo><ChemicalList><Chemical><RegistryNumber>0</RegistryNumber><NameOfSubstance UI="D054392">Adipokines</NameOfSubstance></Chemical><Chemical><RegistryNumber>0</RegistryNumber><NameOfSubstance UI="C422405">activin A</NameOfSubstance></Chemical><Chemical><RegistryNumber>104625-48-1</RegistryNumber><NameOfSubstance UI="D028341">Activins</NameOfSubstance></Chemical><Chemical><RegistryNumber>EC 3.4.24.34</RegistryNumber><NameOfSubstance UI="C488762">MMP8 protein, human</NameOfSubstance></Chemical><Chemical><RegistryNumber>EC 3.4.24.34</RegistryNumber><NameOfSubstance UI="D020784">Matrix Metalloproteinase 8</NameOfSubstance></Chemical></ChemicalList><CitationSubset>IM</CitationSubset><MeshHeadingList><MeshHeading><DescriptorName UI="D028341" MajorTopicYN="N">Activins</DescriptorName><QualifierName UI="Q000378" MajorTopicYN="N">metabolism</QualifierName><QualifierName UI="Q000502" MajorTopicYN="N">physiology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D054392" MajorTopicYN="N">Adipokines</DescriptorName><QualifierName UI="Q000378" MajorTopicYN="Y">metabolism</QualifierName><QualifierName UI="Q000502" MajorTopicYN="N">physiology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D000273" MajorTopicYN="N">Adipose Tissue</DescriptorName><QualifierName UI="Q000502" MajorTopicYN="Y">physiology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D000818" MajorTopicYN="N">Animals</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D001281" MajorTopicYN="N">Atrial Fibrillation</DescriptorName><QualifierName UI="Q000378" MajorTopicYN="N">metabolism</QualifierName><QualifierName UI="Q000473" MajorTopicYN="N">pathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D064752" MajorTopicYN="N">Atrial Remodeling</DescriptorName><QualifierName UI="Q000502" MajorTopicYN="N">physiology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D002478" MajorTopicYN="N">Cells, Cultured</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005260" MajorTopicYN="N">Female</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005355" MajorTopicYN="N">Fibrosis</DescriptorName><QualifierName UI="Q000209" MajorTopicYN="N">etiology</QualifierName><QualifierName UI="Q000473" MajorTopicYN="N">pathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D006325" MajorTopicYN="N">Heart Atria</DescriptorName><QualifierName UI="Q000473" MajorTopicYN="N">pathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D006801" MajorTopicYN="N">Humans</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D008297" MajorTopicYN="N">Male</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D020784" MajorTopicYN="N">Matrix Metalloproteinase 8</DescriptorName><QualifierName UI="Q000378" MajorTopicYN="N">metabolism</QualifierName><QualifierName UI="Q000502" MajorTopicYN="N">physiology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D008875" MajorTopicYN="N">Middle Aged</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D009206" MajorTopicYN="N">Myocardium</DescriptorName><QualifierName UI="Q000473" MajorTopicYN="Y">pathology</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D051381" MajorTopicYN="N">Rats</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D050151" MajorTopicYN="N">Subcutaneous Fat</DescriptorName><QualifierName UI="Q000502" MajorTopicYN="N">physiology</QualifierName></MeshHeading></MeshHeadingList><KeywordList Owner="NOTNLM"><Keyword MajorTopicYN="N">Activin A</Keyword><Keyword MajorTopicYN="N">Atrial fibrillation</Keyword><Keyword MajorTopicYN="N">Atrial fibrosis</Keyword><Keyword MajorTopicYN="N">Epicardial adipose tissue</Keyword><Keyword MajorTopicYN="N">Myocardial fibrosis</Keyword></KeywordList></MedlineCitation><PubmedData><History><PubMedPubDate PubStatus="received"><Year>2012</Year><Month>11</Month><Day>15</Day></PubMedPubDate><PubMedPubDate PubStatus="accepted"><Year>2013</Year><Month>3</Month><Day>4</Day></PubMedPubDate><PubMedPubDate PubStatus="entrez"><Year>2013</Year><Month>3</Month><Day>26</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="pubmed"><Year>2013</Year><Month>3</Month><Day>26</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate><PubMedPubDate PubStatus="medline"><Year>2015</Year><Month>12</Month><Day>29</Day><Hour>6</Hour><Minute>0</Minute></PubMedPubDate></History><PublicationStatus>ppublish</PublicationStatus><ArticleIdList><ArticleId IdType="pubmed">23525094</ArticleId><ArticleId IdType="doi">10.1093/eurheartj/eht099</ArticleId><ArticleId IdType="pii">eht099</ArticleId></ArticleIdList></PubmedData></PubmedArticle><PubmedArticle><MedlineCitation Status="MEDLINE" Owner="NLM"><PMID Version="1">23524949</PMID><DateCompleted><Year>2013</Year><Month>10</Month><Day>23</Day></DateCompleted><DateRevised><Year>2021</Year><Month>10</Month><Day>21</Day></DateRevised><Article PubModel="Electronic"><Journal><ISSN IssnType="Electronic">1940-087X</ISSN><JournalIssue CitedMedium="Internet"><Issue>73</Issue><PubDate><Year>2013</Year><Month>Mar</Month><Day>12</Day></PubDate></JournalIssue><Title>Journal of visualized experiments : JoVE</Title><ISOAbbreviation>J Vis Exp</ISOAbbreviation></Journal>Isolation and Kv channel recordings in murine atrial and ventricular cardiomyocytes. | KCNE genes encode for a small family of Kv channel ancillary subunits that form heteromeric complexes with Kv channel alpha subunits to modify their functional properties. Mutations in KCNE genes have been found in patients with cardiac arrhythmias such as the long QT syndrome and/or atrial fibrillation. However, the precise molecular pathophysiology that leads to these diseases remains elusive. In previous studies the electrophysiological properties of the disease causing mutations in these genes have mostly been studied in heterologous expression systems and we cannot be sure if the reported effects can directly be translated into native cardiomyocytes. In our laboratory we therefore use a different approach. We directly study the effects of KCNE gene deletion in isolated cardiomyocytes from knockout mice by cellular electrophysiology - a unique technique that we describe in this issue of the Journal of Visualized Experiments. The hearts from genetically engineered KCNE mice are rapidly excised and mounted onto a Langendorff apparatus by aortic cannulation. Free Ca(2+) in the myocardium is bound by EGTA, and dissociation of cardiac myocytes is then achieved by retrograde perfusion of the coronary arteries with a specialized low Ca(2+) buffer containing collagenase. Atria, free right ventricular wall and the left ventricle can then be separated by microsurgical techniques. Calcium is then slowly added back to isolated cardiomyocytes in a multiple step comprising washing procedure. Atrial and ventricular cardiomyocytes of healthy appearance with no spontaneous contractions are then immediately subjected to electrophysiological analyses by patch clamp technique or other biochemical analyses within the first 6 hours following isolation. |
13,204 | A common missense variant in the neuregulin 1 gene is associated with both schizophrenia and sudden cardiac death. | Both schizophrenia and epilepsy have been linked to increased risk of sudden cardiac death (SCD). We hypothesized that DNA variants within genes previously associated with schizophrenia and epilepsy may contribute to an increased risk of SCD.</AbstractText>To investigate the contribution to SCD susceptibility of DNA variants previously implicated in schizophrenia and epilepsy.</AbstractText>From the ongoing Oregon Sudden Unexpected Death Study, comparisons were performed among 340 SCD cases presenting with ventricular fibrillation and 342 controls. We tested for the association between 17 single-nucleotide polymorphisms (SNPs) mapped to 14 loci previously implicated in schizophrenia and epilepsy by using logistic regression and assuming additive, dominant, and recessive genetic models.</AbstractText>The minor allele of the nonsynonymous SNP rs10503929 within the neuregulin 1 gene was associated with SCD under all 3 investigated models, with the strongest association for the recessive genetic model (recessive P = 4.01 × 10(-5), odds ratio [OR] 4.04; additive P = 2.84 × 10(-7), OR 1.9; and dominant P = 9.01 × 10(-6), OR 2.06). To validate our findings, we further explored the association of this variant in the Harvard Cohort SCD study. The SNP rs10503929 was associated with an increased risk of SCD under the recessive genetic model (P = .0005, OR 2.7). This missense variation causes a methionine to threonine change and functional effects are currently unknown.</AbstractText>The observed association between a schizophrenia-related neuregulin 1 gene variant and SCD may represent the first evidence of coexisting genetic susceptibility between 2 conditions that have an established clinical overlap. Further investigation is warranted to explore the molecular mechanisms of this variant in the pathogenesis of SCD.</AbstractText>Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,205 | Early vancomycin, amikacin and gentamicin concentrations in pulmonary artery and pulmonary tissue are not affected by VA ECMO (venoarterial extracorporeal membrane oxygenation) in a pig model of prolonged cardiac arrest. | ECMO (extracorporeal membrane oxygenation) is increasingly used in severe hemodynamic compromise and cardiac arrest (CA). Pulmonary infections are frequent in these patients. Venoarterial (VA) ECMO decreases pulmonary blood flow and antibiotic availability in lungs during VA ECMO treated CA is not known. We aimed to assess early vancomycin, amikacin and gentamicin concentrations in the pulmonary artery as well as tracheal aspirate and to determine penetration ratios of these antibiotics to lung tissue in a pig model of VA ECMO treated CA.</AbstractText>Twelve female pigs, body weight 51.5 ± 3.5 kg, were subjected to prolonged CA managed by different modes of VA ECMO. Anesthetized animals underwent 15 min of ventricular fibrillation (VF) followed by continued VF with ECMO flow of 100 mL/kg/min. Immediately after institution of ECMO, a 30 min vancomycin infusion (10 mg/kg) was started and amikacin and gentamicin boluses (7.5 and 3 mg/kg, respectively) were administered. ECMO circuit, aortic, pulmonary arterial, and tracheal aspirate concentrations of antibiotics were measured at 30 and 60 min after administration; penetration ratios were calculated.</AbstractText>All 30 min antibiotic concentrations and 60 min concentration for gentamicin in the pulmonary artery were no different than the aorta. However, the 60 min pulmonary artery vancomycin and amikacin values were significantly higher than aortic, 19.8 (14.3-21.6) vs. 17.6 (14.2-19.0) mg/L, p = 0.009, and 15.6 mg/L (11.0-18.6) vs. 11.2 (10.4-17.2) mg/L, p = 0.036, respectively. One hour penetration ratios were 18.5% for vancomycin, 34.9% for gentamicin and 38.8% for amikacin.</AbstractText>In a pig model of VA ECMO treated prolonged CA, despite diminished pulmonary flow, VA ECMO does not decrease early vancomycin, gentamicin, and amikacin concentrations in pulmonary artery. Within 1 h post administration, antibiotics can be detected in tracheal aspirate in adequate concentrations.</AbstractText>Copyright © 2013 Elsevier Ltd. All rights reserved.</CopyrightInformation> |
13,206 | Direct left ventricular endocardial pacing: an alternative when traditional resynchronization via coronary sinus is not feasible or effective. | Biventricular pacing through the coronary sinus (CS) is effective for the treatment of patients with heart failure and left bundle-branch block. However, this approach is not always feasible. Although surgical epicardial lead implantation is an alternative, the technique may be deleterious in some patients. Thus, direct left ventricular (LV) endocardial pacing under local anesthesia may be an option.</AbstractText>We describe our technique and analyze the results of direct LV endocardial pacing.</AbstractText>Fourteen patients with failed resynchronization via CS (April 2006-September 2011) were selected. Using a femoral approach, we performed transseptal puncture and LV mapping, then fixed the active lead where the longest electrical delay was observed; the generator was placed in the anterior thigh. For resynchronization, eight patients with a device previously implanted through the upper veins received a single-chamber generator that was set to the VVT mode to sense the subclavian pacing spike. Six patients received a complete femoral resynchronization system with either a defibrillator or pacemaker. Patients were followed for 6-54 months.</AbstractText>The LV lead was successfully implanted in all cases. Two patients experienced excessive bleeding and two died during follow-up. All except one improved at least one New York Heart Association class and experienced improved left ventricle ejection fraction. One patient with recurrent episodes of ventricular fibrillation was asymptomatic.</AbstractText>Direct LV endocardial pacing is safe and may be a less risky, more efficient alternative than surgical epicardial lead implantation for resynchronization via CS.</AbstractText>©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.</CopyrightInformation> |
13,207 | Metabolic determinants of electrical failure in ex-vivo canine model of cardiac arrest: evidence for the protective role of inorganic pyrophosphate. | Deterioration of ventricular fibrillation (VF) into asystole or severe bradycardia (electrical failure) heralds a fatal outcome of cardiac arrest. The role of metabolism in the timing of electrical failure remains unknown.</AbstractText>To determine metabolic factors of early electrical failure in an ex-vivo canine model of cardiac arrest (VF+global ischemia).</AbstractText>Metabolomic screening was performed in left ventricular biopsies collected before and after 0.3, 2, 5, 10 and 20 min of VF and global ischemia. Electrical activity was monitored via plunge needle electrodes and pseudo-ECG. Four out of nine hearts exhibited electrical failure at 10.1±0.9 min (early-asys), while 5/9 hearts maintained VF for at least 19.7 min (late-asys). As compared to late-asys, early-asys hearts had more ADP, less phosphocreatine, and higher levels of lactate at some time points during VF/ischemia (all comparisons p<0.05). Pre-ischemic samples from late-asys hearts contained ∼25 times more inorganic pyrophosphate (PPi) than early-asys hearts. A mechanistic role of PPi in cardioprotection was then tested by monitoring mitochondrial membrane potential (ΔΨ) during 20 min of simulated-demand ischemia using potentiometric probe TMRM in rabbit adult ventricular myocytes incubated with PPi versus control group. Untreated myocytes experienced significant loss of ΔΨ while in the PPi-treated myocytes ΔΨ was relatively maintained throughout 20 min of simulated-demand ischemia as compared to control (p<0.05).</AbstractText>High tissue level of PPi may prevent ΔΨm loss and electrical failure at the early phase of ischemic stress. The link between the two protective effects may involve decreased rates of mitochondrial ATP hydrolysis and lactate accumulation.</AbstractText> |
13,208 | Pressure reflection in the pulmonary circulation in patients with severe mitral regurgitation indicates adverse postoperative outcome. | Severe pulmonary hypertension (PH) is a known risk factor in valvular surgery. In the present study, we hypothesized that the assessment of pressure reflection (PR) in the pulmonary circulation, indicating increased pulmonary vascular resistance, might improve the identification of patients with increased morbidity and mortality following surgery for severe mitral regurgitation.</AbstractText>A total of 103 patients without atrial fibrillation were divided into three groups: Group 1 (n = 48), patients without PR; Group 2 (n = 36), patients with PR and pulmonary artery systolic pressure (PASP) ≤ 60 mmHg and Group 3 (n = 19), patients with PR and PASP >60 mmHg. Three variables related to PR were selected: the acceleration time in the right ventricular outflow tract (RVOT), the interval between peak velocity in the RVOT and peak tricuspid regurgitant jet velocity and the right ventricular pressure increase after peak RVOT velocity.</AbstractText>There were no differences between groups in age, ejection fraction, need for coronary bypass grafting or creatinine. Patients with PR (Groups 2 and 3) had more use of vasoactive drugs (overall P < 0.0001, Group 1 vs Group 2 P = 0.018). The proportion of patients with >24 h in the intensive care unit was 27% in Group 1, 54% in Group 2 and 84% in Group 3 (overall P < 0.0001, Group 1 vs Group 2 P = 0.006). The in-hospital mortality in patients without PR (n = 49) was 0% compared with 10.9% in patients with PR (P = 0.029).</AbstractText>Echocardiography assessment of PR in the pulmonary circulation and severe PH may identify patients with adverse outcome following mitral surgery.</AbstractText> |
13,209 | Mitral valve pathology in severely impaired left ventricles can be successfully managed using a right-sided minimally invasive surgical approach. | We sought to review our experience in patients with severely impaired left ventricular function (ejection fraction (EF) ≤ 30%) who underwent minimally invasive mitral valve (MV) surgery (Mini-MV).</AbstractText>Between 1999 and 2010, a total of 3450 patients underwent Mini-MV surgery at our institution. Of these, 177 had severely impaired left ventricular function (EF < 30%, including ischaemic and non-ischaemic cardiomyopathy). Primary indication for surgery was MV regurgitation in all but 5 patients (2.8%), who were diagnosed with mixed regurgitation and stenosis. Mean age of patients was 67 ± 11 years and 110 were male (62.1%). Mean EuroSCORE predicted risk of mortality was 14.7 ± 13.6%.</AbstractText>MV repair was accomplished in 86.4% of patients (n = 153), and MV replacement was performed in 13.6% (n = 24). Primary MV repair included implantation of a rigid annuloplasty ring (mean size 29.5 ± 2.2 mm) in 95.4% of patients, and additional MV procedures as required. Concomitant procedures consisted of tricuspid valve surgery in 15.3% of patients, atrial fibrillation ablation in 27.1% and atrial septal defect/persistent foramen ovale closure in 5.6%. The duration of cardiopulmonary bypass was 123 ± 64 min and aortic cross-clamp time was 67 ± 27 min. Thirty-day mortality was 7.9%. The mean follow-up time was 3 ± 2.5 years, and the follow-up was 94.0% complete. Ten-year survival was 45.5% (95% CI: 35.2-55.9) for the overall group. The rate of MV-related reintervention was 4%, while heart transplantation was performed in 6%.</AbstractText>Mini-MV surgery in patients with significantly impaired left ventricular function can be performed with a reasonable operative mortality and acceptable long-term survival for this high-risk patient cohort.</AbstractText> |
13,210 | Management of ventricular tachycardia in heart failure. | Ventricular tachyarrhythmias are common in patients with congestive heart failure. The clinical presentation ranges from an asymptomatic incidental electrocardiographic finding to palpitations, syncope, and sudden cardiac death. Although implantable cardioverter defibrillators successfully prevent sudden cardiac death associated with ventricular fibrillation and ventricular tachycardia, recurrent implantable cardioverter defibrillators shocks remain a clinical management challenge. In this review, we discuss management strategies of ventricular tachycardia in congestive heart failure, including drug therapy, radiofrequency catheter ablation (RFCA), and recent RFCA advances. |
13,211 | Recurrent pacemaker lead thrombosis in a patient with gene polymorphism: a rare case treated with thrombolytic therapy. | Pacemaker (PM)-related thrombosis is an infrequent complication of pacing. We present the case of a 58-year-old man with heart failure and atrial fibrillation who had recurrent episodes of PM lead thrombosis while undergoing anticoagulation therapy. The patient was admitted to the hospital with complaints of dyspnea and palpitation. Echocardiography revealed normal right ventricular dimensions and an enlarged left ventricle with poor contractility and an ejection fraction of 20%. Transesophageal echocardiography demonstrated a large, mobile thrombus in the right atrium that was attached to the PM lead. The patient was successfully treated with a thrombolytic agent. Genetic tests revealed that the patient was a heterozygous carrier of the methylenetetrahydrofolate reductase (MTHFR) gene mutation. |
13,212 | Dual dispatch early defibrillation in out-of-hospital cardiac arrest in a mixed urban-rural population. | The effects of a system based on minimally trained first responders (FR) dispatched simultaneously with the emergency medical services (EMS) of the local hospital in a mixed urban and rural area in Northwestern Switzerland were examined.</AbstractText>In this prospective study 500 voluntary fire fighters received a 4-h training in basic-life-support using automated-external-defibrillation (AED). FR and EMS were simultaneously dispatched in a two-tier rescue system. During the years 2001-2008, response times, resuscitation interventions and outcomes were monitored. 1334 emergencies were included. The FR reached the patients (mean age 60.4 ± 19 years; 65% male) within 6 ± 3 min after emergency calls compared to 12 ± 5 min by the EMS (p<0.0001). Seventy-six percent of the 297 OHCAs occurred at home. Only 3 emergencies with resuscitation attempts occurred at the main railway station equipped with an on-site AED. FR were on the scene before arrival of the EMS in 1166 (87.4%) cases. Of these, the FR used AED in 611 patients for monitoring or defibrillation. CPR was initiated by the FR in 164 (68.9% of 238 resuscitated patients). 124 patients were defibrillated, of whom 93 (75.0%) were defibrillated first by the FR. Eighteen patients (of whom 13 were defibrillated by the FR) were discharged from hospital in good neurological condition.</AbstractText>Minimally trained fire fighters integrated in an EMS as FR contributed substantially to an increase of the survival rate of OHCAs in a mixed urban and rural area.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,213 | Risk factors for hospital mortality in valve replacement with porcine bioprosthesis at an universitary institution. | Study designed to identify characteristics of patients related to increased hospital mortality after valve replacement, assumed as risk factors.</AbstractText>Retrospective study including 808 patients submitted to the implant of St. Jude Biocor porcine bioprosthesis between 1994 and 2009 at Instituto de Cardiologia do Rio Grande do Sul. Primary outcome was hospital death and hospital mortality was related to demographic and surgical characteristics. Statistics include t-test, qui-square test and logistical regression analysis.</AbstractText>There were 80 (9.9%) hospital deaths. Risk factors identified with univariable logistical analysis (and respective odds-ratio) were: tricuspid surgery (OR 6.11); mitral valve replacement (OR 3.98); left ventricular ejection fraction < 30% (OR 3.82); diabetes mellitus (OR 2.55); atrial fibrillation (OR 2.32); pulmonary arterial hypertension (OR 2.30); serum creatinine > 1,4 mg/dL (OR 2.28); previous cardiac surgery (OR 2.17); systemic arterial hypertension (OR 1.93); functional class III e IV (OR 1.92); coronary bypass (OR 1.81); age > 70 years-old (OR 1.80); congestive heart failure (OR 1.73); e female gender (OR 1.68). Multivariable logistic regression for independent factors identified preponderant risk factors mitral valve replacement (OR 5,29); tricuspid surgery (OR 3.07); diabetes mellitus (OR 2.72); age > 70 years-old (OR 2.62); coronary bypass (OR 2.43); previous cardiac surgery (OR 1.82); e systemic arterial hypertension (OR 1.79).</AbstractText>Mortality rate is within values found in literature. Identification of risk factors could contribute to changes in surgical indication and medical management in order to reduce hospital mortality.</AbstractText> |
13,214 | The knowledge of public access to defibrillation in selected cities in Poland. | The Public Access to Defibrillation (PAD) program was designed to raise the awareness of sudden cardiac death (SCA) pre-hospital management among the community. The goal of the following research was to confirm the final impact of the Polish PAD program on various resident groups that differ by age, training and education level.</AbstractText>The trial total number of participants reached 404 people from three cities divided into two groups. In group one (n = 295) were randomly selected people inside the trial area and in group two (n = 109) we had individuals who were theoretically trained in basic life support (BLS) algorithms, including the use of an automatic external defibrillator (AED). The research method was based on two different questionnaires completed by participants from each group.</AbstractText>The greatest knowledge of SCA, as well as the use of AED, and the best practical skills, were possessed by the residents of cities with a population over 100 000, aged between 18 and 30 years, who completed secondary or higher education (31.7%). The group with the smallest knowledge about SCA lived in the country (10.7%). The second group with little knowledge of the subject consisted mostly of individuals with primary education (4.19%) or professional abilities and over 50 years old (2.16%).</AbstractText>There must be some actions taken in order to increase the community awareness concerning automatic defibrillation. Training on AED and the possibility of practical exercise needs to be organized and should be conducted especially among residents of the countryside and people under 30 or over 50 years old.</AbstractText> |
13,215 | Impact of extracorporeal membrane oxygenation support on clinical outcome of pediatric patients with acute cardiopulmonary failure: a single-center experience. | Conventional therapy against acute pediatric cardiopulmonary failure (APCPF) caused by a variety of disease entities remains unsatisfactory with extremely high morbidity and mortality. For refractory APCPF, extracorporeal membrane oxygenation (ECMO) is one of the last resorts.</AbstractText>In this study, the in-hospital outcomes of pediatric patients with refractory APCPF receiving ECMO support were reviewed.</AbstractText>Between August 2006 and May 2011, a single-center cohort study was performed in pediatric patients who required ECMO support due to cardiogenic shock or severe hypoxemia. A total of 22 patients with mean age of 7.0 ± 6.3 years received ECMO (male = 11; female = 11). The indications included acute fulminant myocarditis (AFM) (n = 6), congenital diaphragmatic hernia (CDH) (n = 3), acute respiratory distress syndrome (ARDS) (n = 6), enterovirus 71 (n = 3), viral sepsis (n = 2), refractory ventricular fibrillation due to long QT syndrome (n = 1), and pulmonary edema with brain herniation (n = 1). Eighteen patients received veno-arterial (VA) mode ECMO, while another four patients undertook the veno-venous (VV) mode. The duration of ECMO use and hospitalization were 6.1 ± 3.1 and 24.4 ± 19.4 days, respectively. The survival rate in patients with AFM was 100% (n = 6). Successful ECMO weaning with uneventful discharge from hospital was noted in 14 (63.6%) patients, whereas in-hospital mortality despite successful ECMO weaning occurred in 5 patients (22.7%). Failure in ECMO weaning and in-hospital death was noted in 3 patients (13.6%).</AbstractText>ECMO resuscitation is an effective strategy in the clinical setting of APCPF.</AbstractText> |
13,216 | [Treatment of arrhythmia in atrial fibrillation]. | The initial therapy after onset of atrial fibrillation (AF) should always include adequate antithrombotic treatment and control of the ventricular rate. Depending on the patient's course, this strategy may prove insufficient and may then be supplemented by rhythm control using drugs or interventions. Clinical frustration came by clinical trials that have demonstrated that the strategy of maintaining sinus rhythm has no demonstrable value when compared with the "laissez-faire" approach of leaving AF to a permanent form and controlling ventricular rate. These disappointing findings can be considered as paradoxical when considering the severe complications associated with AF in epidemiological studies. New anti-arrhythmic approaches might offer added value but this is still a matter of debate. Non-pharmacological interventions to prevent AF recurrences or to limit its expression have been substantially developed in the past decade. Ablation techniques, usually done percutaneously using a catheter, have proved successful n the treatment of AF, particularly by reducing the symptomatic burden associated with the arrhythmia, to such an extent that a 'cure' may be achieved in some patients with paroxysmal AF. |
13,217 | Development and validation of an integrated diagnostic algorithm derived from parameters monitored in implantable devices for identifying patients at risk for heart failure hospitalization in an ambulatory setting. | We developed and validated a heart failure (HF) risk score combining daily measurements of multiple device-derived parameters.</AbstractText>Heart failure patients from clinical studies with implantable devices were used to form two separate data sets. Daily HF scores were estimated by combining changes in intra-thoracic impedance, atrial fibrillation (AF) burden, rapid rate during AF, %CRT pacing, ventricular tachycardia, night heart rate, heart rate variability, and activity using a Bayesian model. Simulated monthly follow-ups consisted of looking back at the maximum daily HF risk score in the preceding 30 days, categorizing the evaluation as high, medium, or low risk, and evaluating the occurrence of HF hospitalizations in the next 30 days. We used an Anderson-Gill model to compare survival free from HF events in the next 30 days based on risk groups.</AbstractText>The development data set consisted of 921 patients with 9790 patient-months of data and 91 months with HF hospitalizations. The validation data set consisted of 1310 patients with 10 655 patient-months of data and 163 months with HF hospitalizations. In the validation data set, 10% of monthly evaluations in 34% of the patients were in the high-risk group. Monthly diagnostic evaluations in the high-risk group were 10 times (adjusted HR: 10.0; 95% CI: 6.4-15.7, P < 0.001) more likely to have an HF hospitalization (event rate of 6.8%) in the next 30 days compared with monthly evaluations in the low-risk group (event rate of 0.6%).</AbstractText>An HF score based on implantable device diagnostics can identify increased risk for HF hospitalization in the next 30 days.</AbstractText> |
13,218 | Therapeutic hypothermia for out-of-hospital ventricular fibrillation survivors: a feasibility study comparing time to achieve target core temperature using conventional conductive cooling versus combined conductive plus pericranial convective cooling. | Mild to moderate therapeutic hypothermia (TH) has been shown to improve survival and neurologic outcome, as well as to reduce healthcare costs in patients resuscitated from out-of-hospital cardiac arrest (OHCA) with ventricular fibrillation. Accordingly, the American Heart Association has categorized this as a Class IB intervention. The therapeutic window for initiating TH is narrow, and thus, achieving target temperature expeditiously is of paramount importance to improve postresuscitative neurologic outcome. The present investigation is a feasibility study designed to assess the practicality and efficacy of including pericranial cooling in our postresuscitative TH protocol. Specifically, we compared time required to achieve target temperature (33°C) using our present standard of TH care (ie, conductive body cooling, conventional TH group) versus combined conductive body cooling plus convective (forced-air) head and neck cooling (combined TH group).</AbstractText>Adult patients who experienced OHCA were included in the study provided TH could be initiated within 4 hours of resuscitation from ventricular fibrillation. Patients enrolled in both groups were cooled using the servo-controlled Arctic Sun conductive cooling system (Medivance, Inc, Louisville, CO). However, patients enrolled in the combined TH group also received forced-air pericranial cooling with an ambient temperature of approximately 13°C. In all cases, the target core (bladder) temperature was 33°C. The primary endpoint (ie, time required to achieve a core temperature of 33°C) was analyzed as a continuous variable and compared between groups using the rank sum test, whereas categorical variables were compared between groups using the chi-square test.</AbstractText>Cardiac intensive care unit at a major tertiary care teaching center in Rochester, MN.</AbstractText>Adult patients who experienced OHCA were included in the study.</AbstractText>Patients enrolled in both groups were cooled using the servo-controlled Arctic Sun conductive cooling system (Medivance, Inc, Louisville, CO). However, patients enrolled in the combined TH group also received forced-air pericranial cooling with an ambient temperature of approximately 13°C.</AbstractText>Only patients admitted after January 1, 2008, were included in the analysis (28 combined TH group patients v 55 conventional TH group patients). Demographic data were similar between groups. When compared with the conventional TH group, time to achieve 33°C was significantly shorter in the combined TH group: 207 minutes (173 and 286 min) [median (25th, 75th percentile)] v 181 minutes (63 and 247 min). The magnitude and frequency of hypothermia-mediated physiologic perturbations (eg, hypokalemia) were similar for both groups.</AbstractText>Both TH cooling paradigms effectively achieved 33°C; however, the combined TH technique significantly decreased the time required to achieve the target temperature. Although not evaluated in this study, such an effect may further improve postresuscitative neurologic outcomes beyond that previously described using conventional TH. Although a positive result (ie, abbreviated time taken to achieve target temperature) was observed, we maintain guarded enthusiasm for this evolving adjunctive technique until corroborative outcome-based evidence is available.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,219 | Death on an LVAD-Two sides of a coin. | LVADs are increasingly being used to support patients with end stage heart failure. As such, the traditional definition of death, the absence of a pulse, requires re-examination as it is no longer clinically relevant. We present two contrasting cases of "death" on LVAD support and present some ethical issues surrounding the end of life on LVAD support. |
13,220 | Outcome of catheter ablation of atrial fibrillation in patients with prior ischemic stroke. | Catheter ablation for atrial fibrillation (AF) has been demonstrated to be effective in a subsets of patients with AF. However, very few data are available in regard to patients with prior history of stroke undergoing catheter ablation. This study aimed to investigate the outcome of catheter ablation in AF patients with prior ischemic stroke.</AbstractText>Between January 2008 and December 2011, of 1897 consecutive patients who presented at Beijing An Zhen Hospital for treatment of drug-refractory AF, 172 (9.1%) patients in the study population had a history of ischemic stroke. All patients underwent catheter ablation and were followed up to assess maintenance of sinus rhythm and recurrence of symptomatic stroke.</AbstractText>Among these 1897 patients, 1768 (93.2%) who had complete follow-up information for a minimum of six months were included in the final analysis. Patients in the stroke group (group I) and the no-stroke group (group II) were similar in regards to gender, body mass index (BMI), history of diabetes, type of AF, and left atrial size. The patients in group I were older than those in group II, and had a higher incidence of hypertension, chronic heart failure, lower left ventricular ejection fraction (LVEF), and higher CHADS2 scores. Six months after ablation, 107 (68.6%) patients in group I and 1403 (87.1%) in group II had discontinued warfarin treatment (P < 0.001). During a median follow-up of (633 ± 415) days, 65 patients in the group I and 638 in group II experienced AF recurrence, and five patients in group I and 28 in group II developed symptomatic stroke. The rates of AF recurrence and recurrent stroke were similar between group I and group II (41.7% vs. 39.6%, P = 0.611; 3.2% vs. 1.7%, P = 0.219; respectively).</AbstractText>Catheter ablation of AF in patients with prior stroke is feasible and efficient.</AbstractText> |
13,221 | Lethal neuroleptic malignant syndrome due to amisulpride. | A 42-year old-man was found lying in his bed having seizures. Later he became unconscious and hypotonic developing mydriasis as well as rigidity. The body core temperature (rectal temperature) was above 42 °C. Blood pH was decreased during treatment, and his general condition deteriorated. The patient developed gasping respiration, ventricular fibrillation, and died. During autopsy and histological investigation cerebral and pulmonary edema were noted together with general congestion of the internal organs. Further observations included contraction bands of myocytes, a contracted spleen, fibrosis of the liver, and gall stones. Toxicological analyses of peripheral blood revealed the following results: amisulpride 4.65 mg/l, biperiden 0.12 mg/l, imipramine 0.33 mg/l, and desipramine 0.68 mg/l. An amisulpride-induced neuroleptic malignant syndrome was therefore diagnosed as the patho-physiological mechanism leading to death. |
13,222 | The comparison in reduction of QT dispersion after primary percutaneous coronary intervention according to existence of thrombectomy in ST-segment elevation myocardial infarction. | Primary percutaneous coronary intervention (PPCI) is the standard treatment in patients with ST-segment elevation myocardial infarction (STEMI). Thrombectomy devices are used to remove thrombus or to prevent embolization of thrombus and plaque during PPCI. QT dispersion (the difference between maximal and minimal QT interval calculated on a standard 12-lead electrocardiogram) represents the regional nonuniformity of ventricular repolarization. It may reflect early coronary reperfusion in reducing electrophysiological instability by decreasing QT dispersion in the recovery phase after acute STEMI.</AbstractText>Our aim was to show whether an additional effect of thrombectomy on reducing QT dispersion will be seen in patients undergoing PPCI for STEMI.</AbstractText>The study population included 80 consecutive patients who were admitted to the hospital within 12 hours after the onset of acute STEMI and angiographic evidence of intraluminal thrombus in the infarct-related artery. Patients with atrial fibrillation or flutter, intraventricular conduction abnormalities, pre-excitation, cardiogenic shock, cardiomyopathy, ventricular hypertrophy, and severe valvular heart disease were excluded from the study.</AbstractText>There were no significant differences between groups regarding gender, age, cardiovascular risk factors, and time from symptom onset to treatment, except for smoking, which was much higher in the PPCI plus thrombectomy group. Infarct-related artery distribution (left anterior descending artery [LAD] to non-LAD), and neither the rate of balloon predilatation nor stent implantation were different between groups. Successful coronary patency was achieved in each case. QT interval measurements were similar between groups at admission. However, at 24 hours, QT and QTc dispersions were less in the PPCI plus thrombectomy group (41 ± 9 vs 33 ± 7 ms, P < 0.05 and 45 ± 8 vs 35 ± 7 ms, P = 0.03, respectively), but not in the other QT interval measurements. When patients were divided into 2 groups according to infarct-related artery (LAD and non-LAD groups), QT interval measurement parameters did not show any significant differences.</AbstractText>Thrombectomy additional to PPCI helps more effective reperfusion at the microvascular level and provides additional prognostic information.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
13,223 | I guideline for cardiopulmonary resuscitation and emergency cardiovascular care -- Brazilian Society of Cardiology: executive summary. | Despite advances related to the prevention and treatment in the past few years, many lives are lost to cardiac arrest and cardiovascular events in general in Brazil every year. Basic Life Support involves cardiovascular emergency treatment mainly in the pre-hospital environment, with emphasis on the early recognition and delivery of cardiopulmonary resuscitation maneuvers focused on high-quality thoracic compressions and rapid defibrillation by means of the implementation of public access-to-defibrillation programs. These aspects are of the utmost importance and may make the difference on the patient's outcomes, such as on hospital survival with no permanent neurological damage. Early initiation of the Advanced Cardiology Life Support also plays an essential role by keeping the quality of thoracic compressions; adequate airway management; specific treatment for the different arrest rhythms; defibrillation; and assessment and treatment of the possible causes during all the assistance. More recently, emphasis has been given to post-resuscitation care, with the purpose of reducing mortality by means of early recognition and treatment of the post-cardiac arrest syndrome. Therapeutic hypothermia has provided significant improvement of neurological damage and should be performed in comatose individuals post-cardiac arrest. For physicians working in the emergency department or intensive care unit, it is extremely important to improve the treatment given to these patients by means of specific training, thus giving them the chance of higher success and of better survival rates. |
13,224 | Heart failure with a normal left ventricular ejection fraction: epidemiology, pathophysiology, diagnosis and management. | Heart failure (HF) with a normal left ventricular (LV) ejection fraction (HFNEF) occurs in 40-71% of patients with HF and carries a prognosis similar to that of HF with a reduced LV ejection fraction (LVEF). The pathophysiology of HFNEF is distinct from that of HF with a reduced LVEF and is characterized by impaired relaxation of myocardium, LV stiffness and, in many cases, increased arterial stiffness. Systemic hypertension accounts for most cases of HFNEF in the United States. Those with HFNEF tend to be older and obese. Diabetes mellitus and atrial fibrillation occur with disproportionately high frequency in HFNEF. The diagnosis of HFNEF requires the presence of symptoms or signs of HF, a normal or near-normal LVEF and evidence of LV diastolic dysfunction based on cardiac catheterization or Doppler echocardiographic techniques and/or elevation of plasma natriuretic peptide levels. Current guidelines for management of HFNEF include control of systolic and diastolic hypertension, control of the ventricular rate in patients with atrial fibrillation and judicious use of diuretics. In selected cases, coronary revascularization or restoration of sinus rhythm in those with atrial fibrillation may be indicated. To date, no drug or drug group has consistently improved survival in HFNEF. For this reason and because of the poor long-term prognosis, preventative measures and effective treatment of underlying causes and precipitating factors are particularly important in avoiding HF exacerbations in patients with HFNEF. |
13,225 | Urgent management of rapid heart rate in patients with atrial fibrillation/flutter and left ventricular dysfunction: comparison of the ultra-short-acting β1-selective blocker landiolol with digoxin (J-Land Study). | A rapid heart rate (HR) during atrial fibrillation (AF) and atrial flutter (AFL) in left ventricular (LV) dysfunction often impairs cardiac performance. The J-Land study was conducted to compare the efficacy and safety of landiolol, an ultra-short-acting β-blocker, with those of digoxin for swift control of tachycardia in AF/AFL in patients with LV dysfunction.</AbstractText>The 200 patients with AF/AFL, HR ≥120beats/min, and LV ejection fraction 25-50% were randomized to receive either landiolol (n=93) or digoxin (n=107). Successful HR control was defined as ≥20% reduction in HR together with HR <110beats/min at 2h after starting intravenous administration of landiolol or digoxin. The dose of landiolol was adjusted in the range of 1-10µg·kg(-1)·min(-1) according to the patient's condition. The mean HR at baseline was 138.2±15.7 and 138.0±15.0beats/min in the landiolol and digoxin groups, respectively. Successful HR control was achieved in 48.0% of patients treated with landiolol and in 13.9% of patients treated with digoxin (P<0.0001). Serious adverse events were reported in 2 and 3 patients in each group, respectively.</AbstractText>Landiolol was more effective for controlling rapid HR than digoxin in AF/AFL patients with LV dysfunction, and could be considered as a therapeutic option in this clinical setting.</AbstractText> |
13,226 | The late Na current as a therapeutic target: where are we? | In this article we review the late Na current which functionally can be measured using patch-clamp electrophysiology (INa,late). This current is largely enhanced under pathological myocardial conditions such as ischemia and heart failure. In addition, INa,late can cause systolic and diastolic contractile dysfunction via a Na-dependent Ca-overload of the myocyte. Moreover, INa,late plays a crucial role as ventricular and atrial proarrhythmic substrate in myocardial pathology by changing cellular electrophysiology. We summarize recent experimental and clinical studies that investigate therapeutic inhibition of this current and discuss the significance of the available data and try to answer not only the question, where we currently are but also where we may go in the near future. This article is part of a Special Issue entitled "Na(+) Regulation in Cardiac Myocytes". |
13,227 | Prevention of sudden cardiac death with implantable cardioverter-defibrillators in children and adolescents with hypertrophic cardiomyopathy. | The aim of this study was to determine the efficacy of implantable cardioverter-defibrillators (ICDs) in children and adolescents with hypertrophic cardiomyopathy (HCM).</AbstractText>HCM is the most common cause of sudden death in the young. The availability of ICDs over the past decade for HCM has demonstrated the potential for sudden death prevention, predominantly in adult patients.</AbstractText>A multicenter international registry of ICDs implanted (1987 to 2011) in 224 unrelated children and adolescents with HCM judged at high risk for sudden death was assembled. Patients received ICDs for primary (n = 188) or secondary (n = 36) prevention after undergoing evaluation at 22 referral and nonreferral institutions in the United States, Canada, Europe, and Australia.</AbstractText>Defibrillators were activated appropriately to terminate ventricular tachycardia or ventricular fibrillation in 43 of 224 patients (19%) over a mean of 4.3 ± 3.3 years. ICD intervention rates were 4.5% per year overall, 14.0% per year for secondary prevention after cardiac arrest, and 3.1% per year for primary prevention on the basis of risk factors (5-year cumulative probability 17%). The mean time from implantation to first appropriate discharge was 2.9 ± 2.7 years (range to 8.6 years). The primary prevention discharge rate terminating ventricular tachycardia or ventricular fibrillation was the same in patients who underwent implantation for 1, 2, or ≥3 risk factors (12 of 88 [14%], 10 of 71 [14%], and 4 of 29 [14%], respectively, p = 1.00). Extreme left ventricular hypertrophy was the most common risk factor present (alone or in combination with other markers) in patients experiencing primary prevention interventions (17 of 26 [65%]). ICD-related complications, particularly inappropriate shocks and lead malfunction, occurred in 91 patients (41%) at 17 ± 5 years of age.</AbstractText>In a high-risk pediatric HCM cohort, ICD interventions terminating life-threatening ventricular tachyarrhythmias were frequent. Extreme left ventricular hypertrophy was most frequently associated with appropriate interventions. The rate of device complications adds a measure of complexity to ICD decisions in this age group.</AbstractText>Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,228 | A randomized trial to assess catheter ablation versus rate control in the management of persistent atrial fibrillation in heart failure. | This study sought to compare catheter ablation with rate control for persistent atrial fibrillation (AF) in heart failure (HF).</AbstractText>The optimal therapy for AF in HF is unclear. Drug-based rhythm control has not proved clinically beneficial. Catheter ablation improves cardiac function in patients with HF, but impact on physiological performance has not been formally evaluated in a randomized trial.</AbstractText>In a randomized, open-label, blinded-endpoint clinical trial, adults with symptomatic HF, radionuclide left ventricular ejection fraction (EF) ≤35%, and persistent AF were assigned to undergo catheter ablation or rate control. Primary outcome was 12-month change in peak oxygen consumption. Secondary endpoints were quality of life, B-type natriuretic peptide, 6-min walk distance, and EF. Results were analyzed by intention-to-treat.</AbstractText>Fifty-two patients (age 63 ± 9 years, EF 24 ± 8%) were randomized, 26 each to ablation and rate control. At 12 months, 88% of ablation patients maintained sinus rhythm (single-procedure success 68%). Under rate control, rate criteria were achieved in 96%. The primary endpoint, peak oxygen consumption, significantly increased in the ablation arm compared with rate control (difference +3.07 ml/kg/min, 95% confidence interval: 0.56 to 5.59, p = 0.018). The change was not evident at 3 months (+0.79 ml/kg/min, 95% confidence interval: -1.01 to 2.60, p = 0.38). Ablation improved Minnesota score (p = 0.019) and B-type natriuretic peptide (p = 0.045) and showed nonsignificant trends toward improved 6-min walk distance (p = 0.095) and EF (p = 0.055).</AbstractText>This first randomized trial of ablation versus rate control to focus on objective exercise performance in AF and HF shows significant benefit from ablation, a strategy that also improves symptoms and neurohormonal status. The effects develop over 12 months, consistent with progressive amelioration of the HF syndrome. (A Randomised Trial to Assess Catheter Ablation Versus Rate Control in the Management of Persistent Atrial Fibrillation in Chronic Heart Failure; NCT00878384).</AbstractText>Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,229 | Ventricular fibrillation associated with complete right bundle branch block. | A substantial number of patients with idiopathic ventricular fibrillation (IVF) present with no specific electrocardiographic (ECG) findings.</AbstractText>To evaluate complete right bundle branch block (RBBB) in patients with IVF.</AbstractText>Patients with IVF showing complete RBBB were included in the present study. Structural and primary electrical diseases were excluded, and provocation tests were performed to exclude the presence of spastic angina or Brugada syndrome (BrS). The prevalence of complete RBBB and the clinical and ECG parameters were compared either in patients with IVF who did not show RBBB or in the general population and age and sex comparable controls with RBBB.</AbstractText>Of 96 patients with IVF, 9 patients were excluded for the presence of BrS. Of 87 patients studied, 10 (11.5%) patients showed complete RBBB. None had structural heart diseases, BrS, or coronary spasms. The mean age was 44 ± 15 years, and 8 of 10 patients were men. Among the ECG parameters, only the QRS duration was different from that of the other patients with IVF who did not show complete RBBB. Ventricular fibrillation recurred in 3:2 in the form of storms, which were well suppressed by isoproterenol. Complete RBBB was found less often in control subjects (1.37%; P < .0001), and the QRS duration was more prolonged in patients with IVF: 139 ± 10ms vs 150 ± 14ms (P = .0061).</AbstractText>Complete RBBB exists more often in patients with IVF than in controls. A prolonged QRS complex suggests a conduction abnormality. Our findings warrant further investigation of the role of RBBB in the development of arrhythmias in patients with IVF.</AbstractText>Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,230 | Contemporary prevalence and correlates of incident heart failure with preserved ejection fraction. | We assessed the prevalence of preserved left ventricular ejection fraction in patients with incident heart failure and differences in the demographic and clinical characteristics that may differentiate patients presenting with heart failure with preserved versus reduced left ventricular ejection fraction.</AbstractText>We identified all patients with newly diagnosed heart failure between 2005 and 2008 from 4 sites in the Cardiovascular Research Network on the basis of hospital discharge and ambulatory visit diagnoses, and assigned a category of preserved, borderline, or reduced left ventricular ejection fraction using data from electronic databases and chart review.</AbstractText>We identified 11,994 patients with incident heart failure; of these, 6210 (51.8%) had preserved left ventricular ejection fraction, 1870 (15.6%) had borderline systolic dysfunction, and 3914 (32.6%) had reduced left ventricular ejection fraction. For those with heart failure with preserved left ventricular ejection fraction, the mean age was 74.7 years and 57.1% were women; for those with borderline systolic dysfunction, the mean age was 71.6 years and 38.4% were women; and for those with reduced left ventricular ejection fraction, the mean age was 69.1 years and 32.6% were women. Compared with white patients, black patients were less likely to have heart failure with preserved systolic function. Those with a history of coronary artery bypass surgery, mitral or aortic valvular disease, atrial fibrillation or flutter, or a diagnosis of hypertension were more likely to have heart failure with preserved systolic function, as were those with a diverse range of noncardiac comorbid conditions, including chronic lung disease, chronic liver disease, a history of a hospitalized bleed, a history of a mechanical fall, a diagnosis of depression, and a diagnosis of dementia. Patients with a history of acute myocardial infarction and a history of ventricular fibrillation or ventricular tachycardia were less likely to have heart failure with preserved left ventricular ejection fraction. Patients with higher systolic blood pressures at baseline and lower low-density lipoprotein levels were more likely to have heart failure with preserved left ventricular ejection fraction, as were those with lower hemoglobin levels and the lowest glomerular filtration rates.</AbstractText>Heart failure with preserved left ventricular ejection fraction is the most common form of the heart failure syndrome among patients newly presenting with this condition, and women and older adults are especially affected. Evidence-based treatment strategies apply to less than one third of patients with newly diagnosed heart failure.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,231 | S4153R is a gain-of-function mutation in the cardiac Ca(2+) release channel ryanodine receptor associated with catecholaminergic polymorphic ventricular tachycardia and paroxysmal atrial fibrillation. | Mutations in ryanodine receptor 2 (RYR2) gene can cause catecholaminergic polymorphic ventricular tachycardia (CPVT). The novel RYR2-S4153R mutation has been implicated as a cause of CPVT and atrial fibrillation. The mutation has been functionally characterized via store-overload-induced Ca(2+) release (SOICR) and tritium-labelled ryanodine ([(3)H]ryanodine) binding assays. The S4153R mutation enhanced propensity for spontaneous Ca(2+) release and reduced SOICR threshold but did not alter Ca(2+) activation of [(3)H]ryanodine binding, a common feature of other CPVT gain-of-function RYR2 mutations. We conclude that the S4153R mutation is a gain-of-function RYR2 mutation associated with a clinical phenotype characterized by both CPVT and atrial fibrillation. |
13,232 | Delayed recovery of spontaneous circulation following cessation of cardiopulmonary resuscitation in an older patient: a case report. | This report describes the apparent 'resurrection' of a patient in an emergency department setting. Befittingly named the 'Lazarus phenomenon', the recovery of spontaneous circulation after cessation of cardiopulmonary resuscitation is an extremely rare occurrence that was first described in 1982 and has been mentioned only 38 times in the medical literature. Our patient's case is remarkable in that it helps illustrate many of the mechanisms of this rare phenomenon. It also serves as a reminder of our limitations in determining when to terminate cardiopulmonary resuscitation and suggests that cessation of cardiopulmonary resuscitation should be approached with more care.</AbstractText>An 89-year-old Caucasian woman with a medical history of hypertension, atrial fibrillation, hypothyroidism, aortic insufficiency, lymphedema and hypoxia secondary to partial lung resection presented to our hospital after a witnessed fall unassociated with head trauma or loss of consciousness. On examination, our patient was saturating at 85 percent and exhibited a decreased range of motion of the upper extremities and left hip. Radiographic images revealed a left femoral neck and left distal radius fracture. Our patient was stabilized on 100 percent fraction of inspired oxygen and was awaiting transfer to an in-patient unit when, at 3:30 a.m., she went into cardiac arrest. An advanced cardiac life support protocol was initiated, at which time our patient was intubated and administered epinephrine, vasopressin and sodium bicarbonate. Our patient remained unresponsive and asystolic so cardiopulmonary resuscitation was abandoned at 3:48 a.m. After five minutes a ventricular contraction was noted at 3:51 a.m. This progressed to sinus rhythm with a pulse at 3:53 a.m. Our patient was stabilized on norepinephrine and moved to our Intensive Care Unit. At 10:55 a.m., however, our patient again arrested and, despite resuscitative efforts, was pronounced dead at 11:03 a.m.</AbstractText>Our patient's case clearly illustrates many of the proposed mechanisms for delayed return of spontaneous circulation including pulmonary hyper-inflation, hyperkalemia, delayed drug onset, and embolism dislodgement. Our patient represents a humbling and disturbing reminder that our medical acumen does not necessarily dictate the fate of our patients and that the decision to discontinue cardiopulmonary resuscitation should be approached with care by incorporating techniques such as end-tidal carbon dioxide, ventilator disconnect and passive monitoring.</AbstractText> |
13,233 | B-type natriuretic peptide predicts left atrial appendage thrombus in patients with nonvalvular atrial fibrillation. | To investigate whether plasma B-type Natriuretic peptide (BNP), a surrogate of left ventricular filling pressure (LVFP), is predictive of left atrial appendage thrombus (LAAT) in patients with nonvalvular atrial fibrillation (AF) independent of known clinical risk predictors.</AbstractText>We conducted a retrospective cohort study of 297 consecutive subjects with AF who underwent a clinically indicated transesophageal echocardiogram (TEE) to evaluate for LAAT and spontaneous echo contrast (SEC). Among those, 136 had a clinically indicated BNP level. Using multivariate logistic regression analysis models, we determined factors independently predictive of the primary endpoint of LAAT and the secondary endpoint of either LAAT or SEC.</AbstractText>Nineteen subjects (6.4%) had LAAT and they were found to have a higher mean CHADS2 score (2.53 vs 1.76, P = 0.01) and mean BNP level [1949 vs. 819 pg/mL, P = 0.001] than those without LAAT. None of the patients with a BNP level ≤500 pg/mL had LAAT. Multivariate logistic regression analysis demonstrated that BNP was predictive of LAAT and the composite of LAAT/SEC independent of the CHADS2 score and warfarin therapy [OR = 1.23 and 1.6 per 500 pg/mL increment in BNP, P-values = 0.03 and 0.001; respectively]. Moreover, adding BNP to the predictive model negated the influence of the CHADS2 score.</AbstractText>These data indicate that BNP is an independent predictor of LAAT in AF and may complement the role of the CHADS2 score in predicting stroke risk.</AbstractText>© 2013, Wiley Periodicals, Inc.</CopyrightInformation> |
13,234 | Outcomes of repeat catheter ablation using magnetic navigation or conventional ablation. | After initial catheter ablation, repeat procedures could be necessary. This study evaluates the efficacy of the magnetic navigation system (MNS) in repeat catheter ablation as compared with manual conventional techniques (MANs).</AbstractText>The results of 163 repeat ablation procedures were analysed. Ablations were performed either using MNS (n = 84) or conventional manual ablation (n = 79). Procedures were divided into four groups based on the technique used during the initial and repeat ablation procedure: MAN-MAN (n = 66), MAN-MNS (n = 31), MNS-MNS (n = 53), and MNS-MAN (n = 13). Three subgroups were analysed: supraventricular tachycardias (SVTs, n = 68), atrial fibrillation (AF, n = 67), and ventricular tachycardias (VT, n = 28). Recurrences were assessed during 19 ± 11 months follow-up. Overall, repeat procedures using MNS were successful in 89.0% as compared with 96.2% in the MAN group (P = ns). The overall recurrence rate was significantly lower using MNS (25.0 vs. 41.4%, P = 0.045). Acute success and recurrence rates for the MAN-MAN, MAN-MNS, MNS-MNS, and MNS-MAN groups were comparable. For the SVT subgroup a higher acute success rate was achieved using MAN (87.9 vs. 100.0%, P = 0.049). The use of MNS for SVT is associated with longer procedure times (205 ± 82 vs. 172 ± 69 min, P = 0.040). For AF procedure and fluoroscopy times were longer (257 ± 72 vs. 185 ± 64, P = 0.001; 59.5 ± 19.3 vs. 41.1 ± 18.3 min, P < 0.001). Less fluoroscopy was used for MNS-guided VT procedures (22.8 ± 14.7 vs. 41.2 ± 10.9, P = 0.011).</AbstractText>Our data suggest that overall MNS is comparable with MAN in acute success after repeat catheter ablation. However, MNS is related to fewer recurrences as compared with MAN.</AbstractText> |
13,235 | Ridge-related reentry: a variant of perimitral atrial tachycardia. | The ridge between the left pulmonary veins (PV) and the left atrial appendage composes part of the lateral mitral isthmus (LMI). Following circumferential PV isolation and LMI linear ablation for the treatment of atrial fibrillation (AF), a critical pathway might develop over the ridge leading to a ridge-related reentry (RRR).</AbstractText>Out of 61 patients who underwent circumferential PV isolation appended by LMI ablation, 5 patients developed RRR. The diagnosis of RRR was based on (1) macro-reentrant atrial tachycardia involving the septum, anterior and inferior wall of the left atrium; (2) slow conduction along the ridge; (3) wide-split double potentials in the ventricular aspect of the LMI were identified with the coronary sinus (CS) electrodes. RRR was investigated with electroanatomical mapping and entrainment mapping and catheter ablation was carried out in all patients. The mean cycle length (CL) of RRR was 312 ± 82 milliseconds and the PPIs at the left atrial septum, inferior and anterior wall during RRR were 10 ± 6, 12 ± 8, 9 ± 5 milliseconds longer than the RRR CL. The interval of the double potentials recorded in the CS electrodes crossing the LMI was 164 ± 38 milliseconds during RRR and the PPI on the LMI near the mitral annulus was 57 ± 10 milliseconds longer than the RRR CL. Catheter ablation was performed anatomically by targeting the ridge and successfully terminated RRR.</AbstractText>After circumferential PV isolation and ablation for LMI in patients with AF, RRR can develop by utilizing the surviving myocardial tissue of the ridge as a critical pathway.</AbstractText>© 2013 Wiley Periodicals, Inc.</CopyrightInformation> |
13,236 | Associations between cardiac fibrosis and permanent atrial fibrillation in advanced heart failure. | Atrial fibrosis is considered as the basis in the development of long-standing atrial fibrillation (AF). However, in advanced heart failure (HF), the independent role of fibrosis for AF development is less clear since HF itself leads to atrial scarring. Our study aimed to differentiate patients with AF from patients without AF in a population consisting of patients with advanced HF. Myocardial samples from the right atrial and the left ventricular wall were obtained during heart transplantation from the explanted hearts of 21 male patients with advanced HF. Long-standing AF was present in 10 of them and the remaining 11 patients served as sinus rhythm controls. Echocardiographic and hemodynamic measurements were recorded prior to heart transplantation. Collagen volume fraction (CVF), transforming growth factor-beta (TGF-beta), and connective tissue growth factor (CTGF) expression in myocardial specimens were assessed histologically and immunohistochemically. The groups were well matched according to age (51.9+/-8.8 vs. 51.3+/-9.3 y) and co-morbidities. The AF group had higher blood pressure in the right atrium (13.6+/-7.7 vs. 6.0+/-5.0 mmHg; p=0.02), larger left atrium diameter (56.1+/-7.7 vs. 50+/-5.1 mm; p=0.043), higher left atrium wall stress (18.1+/-2.1 vs. 16.1+/-1.7 kdynes/m(2); p=0.04), and longer duration of HF (5.0+/-2.9 vs. 2.0+/-1.6 y, p=0.008). There were no significant differences in CVF (p=0.12), in CTGF (p=0.60), and in TGF-beta expression (p=0.66) in the atrial myocardium between the two study groups. In conclusions, in advanced HF, atrial fibrosis expressed by CVF is invariably present regardless of occurrence of AF. In addition to atrial wall fibrosis, increased wall stress might contribute to AF development in long-standing AF. |
13,237 | Independent role of left ventricular global longitudinal strain in predicting prognosis of chronic heart failure patients. | To evaluate the independent prognostic role of two-dimensional (2D) strain measures reflecting global longitudinal left ventricular (LV) systolic function in outpatients affected by chronic heart failure (CHF).</AbstractText>Global longitudinal LV systolic strain (GLS) was assessed in 308 outpatients affected by CHF, by analyzing standard views with 2D speckle tracking technique. During a mean follow-up of 26 ± 13 months 37 patients died (29 due to cardiovascular causes), 10 patients underwent heart transplantation, and 75 patients experienced at least 1 episode of hospitalization due to acute decompensated heart failure (ADHF). Thirty-one patients without a history of major ventricular arrhythmic events experienced the occurrence of ventricular fibrillation and/or tachycardia or sudden death was observed. Multivariate Cox regression analysis showed that GLS was significantly associated with all-cause mortality (HR: 1.15; 95%CI: 1.02-1.30; P: 0.026), cardiovascular death (HR: 1.20; 95%CI: 1.04-1.39; P: 0.011), cardiovascular death or heart transplantation (HR: 1.24; 95%CI: 1.09-1.41; P: 0.001), ADHF-related hospitalizations (HR: 1.15; 95%CI: 1.05-1.25; P: 0.003), and arrhythmic events (HR: 1.17; 95%CI: 1.03-1.33; P: 0.018).</AbstractText>Quantifying LV longitudinal systolic function in CHF outpatients on the basis of 2D speckle tracking analysis provides a new parameter that independently predicts patient outcome, thus, strengthening its possible role in current clinical practice.</AbstractText>© 2013, Wiley Periodicals, Inc.</CopyrightInformation> |
13,238 | Novel surgical ablation through a septal-superior approach for valvular atrial fibrillation: 7-year single-centre experience. | We previously reported favourable short-term results of our 'trans-septal maze procedure', a novel technique for creating biatrial lesions through a septal-superior approach during mitral valve surgery. Here, we reviewed the mid-term results of this procedure and determined the impact of restored left atrial (LA) contraction on late outcomes.</AbstractText>We examined clinical data of 50 patients with persistent (n = 7) or long-standing persistent atrial fibrillation (AF) (n = 43) (mean period of rhythm disturbance 77 ± 78 months) who underwent a trans-septal maze procedure concomitant with mitral valve surgery and were followed postoperatively for at least 24 months. The mean preoperative LA dimension was 59 ± 9 mm (40-85 mm). The presence of an A wave in Doppler echocardiography was considered to indicate evidence of LA mechanical contraction. Serial echocardiography was performed to evaluate left ventricular and LA dimensions, degree of valvular regurgitation and estimated systolic pulmonary artery (PA) pressure. Follow-up was completed with a mean duration of 59 ± 17 months (27-92 months).</AbstractText>There were no ablation-related complications and 48 patients (96%) were free from AF immediately after the operation. At the latest follow-up, 39 patients (78%) were free from AF, while 28 (56%) presented LA mechanical contraction. Patients who restored LA mechanical contraction were less likely to experience postoperative thromboembolic events (4 vs 23%, P = 0.075), as compared with those who did not restore it. Serial echocardiography showed that patients with restored LA contraction showed improvement in Doppler-derived systolic PA pressure to a greater degree and less incidence of significant tricuspid regurgitation (7 vs 41%, P = 0.006). The Cox proportional hazards models with adjustments for all other covariates revealed LA dimension >60 mm at baseline as an independent risk factor for lack of LA mechanical contraction (adjusted hazards ratio 3.9, 95% confidence interval 1.1-14, P = 0.035).</AbstractText>Our trans-septal maze procedure may be an effective alternative surgical treatment for eliminating AF during mitral valve surgery. In patients with valvular AF, early surgery is warranted to restore sinus rhythm with LA mechanical contraction, before severe LA dilatation occurs. The impact of LA contraction recovery conferred by AF ablation on postoperative haemodynamic improvements and thromboembolic events remains to be determined.</AbstractText> |
13,239 | Hypothermia-induced neuroprotection is associated with reduced mitochondrial membrane permeability in a swine model of cardiac arrest. | Increasing evidence has shown that mild hypothermia is neuroprotective for comatose patients resuscitated from cardiac arrest, but the mechanism of this protection is not fully understood. The aim of this study was to determine whether prolonged whole-body mild hypothermia inhibits mitochondrial membrane permeability (MMP) in the cerebral cortex after return of spontaneous circulation (ROSC). Thirty-seven inbred Chinese Wuzhishan minipigs were successfully resuscitated after 8 minutes of untreated ventricular fibrillation (VF) and underwent recovery under normothermic (NT) or prolonged whole-body mild hypothermic (HT; 33°C) conditions for 24 or 72 hours. Cerebral samples from the frontal cortex were collected at 24 and 72 hours after ROSC. Mitochondria were isolated by differential centrifugation. At 24 hours, relative to NT, HT was associated with reductions in opening of the mitochondrial permeability transition pore, release of pro-apoptotic substances from mitochondria, caspase 3 cleavage, apoptosis, and neurologic deficit scores, as well as increases in mitochondrial membrane potential and mitochondrial respiration. Together, these findings suggest that mild hypothermia inhibits ischemia-induced increases in MMP, which may provide neuroprotection against cerebral injury after cardiac arrest. |
13,240 | Long term survival in patients with cardiac amyloidosis. Prevalence and characterisation during follow-up. | Cardiac amyloidosis (CA) is usually characterised by a poor outcome in the short-term; clinical and instrumental features are heterogeneous and could characterise subgroups with different prognoses. The aim of our study was to describe a subgroup of patients with CA showing an impressive favourable long-term survival.</AbstractText>Out of 50 patients (males 65%, 63 ± 11 years) with an echocardiographic and bioptic diagnosis of CA observed from 1991 to 2009, we selected a subgroup of patients surviving more than 50 months from diagnosis (group 1). We described their features at enrolment and during follow-up, comparing them with patients surviving less than 12 months (group 2).</AbstractText>We found seven patients (14%) belonging to group 1 and 26 (52%) to group 2. Four out of seven long term survivors suffered from AL amyloidosis, in one case the underlying aetiology was a chronic inflammatory disease, while in two cases remained unknown. At enrolment, group 1 patients showed higher systolic blood pressure with respect to group 2 (140 ± 25 vs. 112 ± 18 mmHg, respectively, p=0.011), and a less thick interventricular septum (IVS) (IVS thickness > 15 mm in 29% vs. 69% of patients, p = 0.049). No patient of group 1 presented left ventricular restrictive filling pattern (0 vs. 31% in group 1 and 2 respectively, p = 0.035), atrial fibrillation (0 vs. 35%, p = 0.024), or progression towards a more severe disease during follow-up.</AbstractText>A not negligible proportion of patients with CA can have a long-term survival. They showed a less severe disease at diagnosis, with substantial stability over time. Further studies on larger populations are necessary to understand the mechanisms underlying this more favourable natural history of the disease.</AbstractText>Copyright © 2013 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.</CopyrightInformation> |
13,241 | Association of blood pressure and aortic distensibility with P wave indices and PR interval: the multi-ethnic study of atherosclerosis (MESA). | Hypertension is an established risk factor for atrial fibrillation. Understanding the association of blood pressure (BP) levels and aortic distensibility with P wave indices (PWIs) and PR interval, intermediate phenotypes of atrial fibrillation, could provide insights into underlying mechanisms.</AbstractText>This analysis included 3180 men and women aged 45-84years participating in the Multi-Ethnic Study of Atherosclerosis, a community-based cohort in the United States. Aortic distensibility was evaluated in 2243 of these individuals using cardiac magnetic resonance imaging. PWIs and PR interval were automatically measured in standard 12-lead ECGs. Sitting BP and other cardiovascular risk factors were assessed using standardized protocols. Left ventricular mass was measured by magnetic resonance imaging.</AbstractText>Higher systolic BP, and diastolic BPs and greater pulse pressure were associated with a significantly greater P wave terminal force. These associations, however, were markedly attenuated or disappeared after adjustment for left ventricular mass. Systolic BP, diastolic BP, and pulse pressure were not strongly associated with PR interval or maximum P wave duration. Reduced aortic distensibility was associated with a longer PR interval but not with PWIs: compared with individuals in the top quartile of aortic distensibility, participants in the lowest quartile had on average a 3.7-ms longer PR interval (95% CI: 0.7, 6.7, p=0.02), after multivariable adjustment.</AbstractText>In this large community-based sample, associations of BP and aortic distensibility with PWIs and PR interval differed. These results suggest that processes linking hypertension with the electrical substrate of atrial fibrillation, as characterized by these intermediate phenotypes, are diverse.</AbstractText>Copyright © 2013 Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,242 | [Diagnosis and treatment of hypertrophic cardiomyopathies]. | Hypertrophic cardiomyopathy is the most common inherited disease of the heart with a prevalence of 0.2 %. One third of patients show no obstruction of the left ventricular outflow tract, whereas two third develop a significant gradient under resting conditions and/or on exertion. Angina pectoris, dyspnea, syncope, heart failure und atrial fibrillation are typical clinical features. Apart from ECG and echocardiography, holter ECG and exercise testing via ergospirometry should be routinely used to identify an adverse clinical course and potential risk factors. Cardiac MRI is a complementary and comprehensive imaging modality and further aids in risk stratification for sudden cardiac death and ICD-implantation for primary prophylaxis. Mainstay of conservative therapy are betablockers, and novel pharmacological approaches are to be expected in the near future. Symptomatic patients with outflow tract obstruction benefit from septum-reducting therapy either by surgical myectomy or catheter-based septum ablation (TASH/PTSMA) with ethanol injection. |
13,243 | Effects of Kaempferia parviflora Wall. Ex. Baker on electrophysiology of the swine hearts. | <AbstractText Label="BACKGROUND & OBJECTIVES" NlmCategory="OBJECTIVE">Pre-clinical studies in swine have demonstrated that a supratherapeutic concentration of sildenafil citrate decreased defibrillation efficacy and facilitated cardiac arrhythmia. We therefore, decided to investigate the effects of Kaempferia parviflora (KP) extract on these parameters in the swine heart. The underlying assumption was that in the heart, KP might be producing effects similar to sildanafil citrate as KP has long been used in southeast Asian traditional medicine to correct erectile dysfunction.</AbstractText>The study was conducted as the defibrillation study, and ventricular fibrillation (VF) induction study. In both studies, the defibrillation threshold (DFT), the upper limit of vulnerability (ULV) and VF threshold were determined before and after KP extract administration.</AbstractText>In both studies KP extract at high concentrations (100 and 50 mg/kg) significantly increased the DFT and ULV, without altering the VF threshold. At these concentrations, systolic and diastolic blood pressures were also attenuated.</AbstractText><AbstractText Label="INTERPRETATION & CONCLUSIONS" NlmCategory="CONCLUSIONS">High concentrations of KP extract attenuated defibrillation efficacy and increased cardiac vulnerability to arrhythmia in a normal swine heart. When used in appropriate concentrations, its blood pressure lowering effect may be useful in hypertensive states. Further studies need to be done to elucidate its mechanism of action.</AbstractText> |
13,244 | [Weight loss pills purchased on the internet as the cause of ventricular fibrillation]. | We present a case regarding a 25-year-old woman who had been taking unauthorized weight loss pills prior to a sudden cardiac arrest from which she was resuscitated by paramedics. Her initial electrocardiogram revealed a prolonged corrected QT-interval (QTc). During admission she developed torsades de pointes and was treated with magnesium sulphate and temporary pacing. An electrophysiological study, a coronary angiogram and genetic testing for long QT syndrome all revealed normal results. After cessation of the pills the QTc normalized, and two weeks later she was discharged. |
13,245 | [A case of thoracic endovascular aortic repair using a transapical approach through the left ventricular apex for an ascending aortic pseudoaneurysm]. | We report a case of a patient with two previous histories of resection of thymoma using median sternotomy and repair for an ascending aortic pseudoaneurysm using median thoracotomy undergoing endovascular aortic repair of the recurrence of pseudoaneurysm in the same site. Due to severe adhesion and calcification in the tissue after two histories of thoracotomy, we expected it impossible to repair the pseudoaneurysm with open thracotomy. We concluded that endovascular aortic repair was the best way for the case. Only problem was the limitation of the characters of current devices for thoracic endovascular aortic repair. If the procedure is done in the ordinary way, the tips of stent graft delivery systems are so long that there may be a danger of damaging the aortic valve, coronary artery, and left ventricle. This is why we decided to use a transapical approach through the left ventricular apex by using left thoracotomy. For the operation, an arterial line and central venous line were secured and one-lung ventilation was performed. We used femoral-femoral bypass to prepare for unexpected bleeding. During the deployment of the stent graft, ventricular fibrillation was produced by the fibrillator to locate in the appreciate site. In the end, the operation was successful. |
13,246 | [A case of fulminant myocarditis successfully treated by percutaneous cardiopulmonary support after 50 minuite-cardiopulmonary resuscitation]. | We report a case of an 8-year-old girl with fulminant myocarditis successfully treated with percutaneous cardiopulmonary support (PCPS). She was first taken to our hospital for treatment of suspected infective enterocolitis since her main symptoms were fever, vomiting and diarrhea. On day 2 after admission, her ECG showed wide QRS and echocardiography demonstrated severe hypokinesis. She was transferred to the ICU with suspected acute myocarditis. On admission to the ICU, circulatory collapse was not detected. ECG showed severe bradycardia and ventricular fibrillation after intubation. Cardiopulmonary resuscitation was performed immediately for 50 minutes prior to initiation of PCPS. She was treated intensively with catecholamines, plasma exchange, continuous hemodiafiltration, high-dose gamma-globulin, and high dose methylprednisolone. Hypothermia therapy was also performed. She was weaned from PCPS on day 6 after initiation of PCPS. The patient was finally discharged from the hospital without any neurological complications on day 68 after weaning from PCPS. The proportion of patients in whom cardiopulmonary resuscitation was performed or having ventricular tachycardia or fibrillation were higher in non-survivors than in survivors. |
13,247 | Strict heart rate control attenuates prothrombotic state and platelet activity in patients with non-valvular permanent atrial fibrillation. | The underlying mechanisms of increased risk of thrombo-embolism in atrial fibrillation (AF) are not completely understood; however, substantial evidence supports that AF is associated with a prothrombotic state. Accordingly, we hypothesized that strict rate control could attenuate platelet activity and thrombotic state in patients with non-valvular AF.</AbstractText>Seventy-five patients with non-valvular AF were divided into 2 groups based on heart rate: (1) normal ventricular rate (n = 34, 18 female) and (2) high ventricular rate (n = 39). Thirty-three sex- and age-matched subjects in sinus rhythm were included as control. Thirty patients with high ventricular rate (16 female) were successfully followed. Markers of platelet function were measured at baseline and repeated 1-month after adequate rate control in high ventricular rate group.</AbstractText>Serum fibrinogen levels were significantly higher in AF patients with high ventricular rate than that in controls. Mean platelet volume, soluble CD40L and β-Thromboglobulin were significantly higher in AF patients with high ventricular rate than those in both AF patients with normal ventricular rate and controls. Soluble CD40L and β-Thromboglobulin were significantly higher in AF patients with normal ventricular rate than those in controls. One-month after adequate rate control, serum fibrinogen, soluble CD40L and β-Thromboglobulin levels significantly decreased (from 2.26 ± 1.02, 85.01 ± 37.05, 3.10 ± 0.90 to 1.55 ± 1.08, 66.34 ± 33.72, 2.71 ± 0.53; p < 0.001, p = 0.002, p = 0.03, respectively) in high ventricular rate group.</AbstractText>AF patients with high ventricular rate had increased indices of platelet activity and thrombotic state. Furthermore, strict rate control significantly decreased indices of thrombotic state and platelet activity in those patients.</AbstractText> |
13,248 | Automated external defibrillator documented degeneration of pre-excited atrial fibrillation into ventricular fibrillation. | Wolff-Parkinson-White (WPW) syndrome can be the cause of syncope or sudden cardiac death, which results from ventricular fibrillation (VF) degenerated from rapid anterograde conduction of atrial fibrillation (AF) to the ventricles through the accessory pathway. We present a case of WPW syndrome in which recording the actual moment of onset of the degeneration of pre-excited AF into VF. This was fortuitous and also lucky for this patient. |
13,249 | Reversing dabigatran in life-threatening bleeding occurring during cardiac ablation with factor eight inhibitor bypassing activity. | We report a case of a patient receiving dabigatran who developed a life-threatening bleeding complication during cardiac ablation that rapidly resolved after administration of Factor Eight Inhibitor Bypassing Activity (FEIBA).</AbstractText>Therapeutic anticoagulation with warfarin during cardiac ablation has been shown to reduce the risk of stroke and systemic embolism. Cardiac tamponade is a potentially life-threatening procedural complication requiring emergent reversal of anticoagulation and pericardiocentesis. Dabigatran is superior to warfarin in preventing stroke and systemic embolism in nonvalvular atrial fibrillation, but has not been evaluated for use during cardiac ablation. Dabigatran is without a known reversal agent and, should tamponade occur during ablation, it is unclear what reversal strategy could be used to establish hemostasis.</AbstractText>A 67-year-old man with history of atrial fibrillation with rapid ventricular rate, two previous atrial fibrillation ablations, and prescribed dabigatran 150 mg bid was admitted for an atrial fibrillation ablation procedure. The last dabigatran dose was 7 hours prior to procedure. During the procedure, a transseptal perforation occurred, requiring an emergent pericardiocentesis. Within 60 minutes, approximately 4.5 L of blood was removed via the pericardiocentesis. Low-dose FEIBA (3159 units, 26 U/kg actual body weight) over 15 minutes was administered. Hemostasis was noted within minutes of initiating the infusion with cessation of bleeding after administration was complete.</AbstractText>This case report describes the potential ability of a low dose of the activated prothrombin complex concentrate, FEIBA, to reestablish hemostasis independent of the pharmacologic effects of dabigatran. Additional studies are warranted to confirm the findings of our observation.</AbstractText> |
13,250 | Supraventricular tachycardias: proposal of a diagnostic algorithm for the narrow complex tachycardias. | The narrow complex tachycardias (NCTs) are defined by the presence in a 12-lead electrocardiogram (ECG) of a QRS complex duration less than 120ms and a heart rate greater than 100 beats per minute; those are typically of supraventricular origin, although rarely narrow complex ventricular tachycardias have been reported in the literature. As some studies document, to diagnose correctly the NCTs is an arduous exercise because sometimes those have similar presentation on the ECG. In this paper, we have reviewed the physiopathological, clinical, and ECG findings of all known supraventricular tachycardias and, in order to reduce the possible diagnostic errors on the ECG, we have proposed a quick and accurate diagnostic algorithm for the differential diagnosis of NCTs. |
13,251 | Safety of therapeutic hypothermia in post VF/VT cardiac arrest patients. | Therapeutic hypothermia (TH) is a process of cooling a patient post ventricular tachycardia/ventricular fibrillation (VT/VF) cardiac arrest to 32-34 degrees C for 24 hours. This improves neurological outcome and is part of current guidelines. Hypothermia prolongs QT interval, which can precipitate torsades de pointes (TdP). We performed a retrospective review of all patients who received TH in our hospital over a period of 2 years to assess the effect of TH on the corrected OT interval (QTc) and any possible pro-arrhythmia. A total of 13 patients received TH. QTc prolonged in all patients with an average of 80.3 + 57.2 ms., and up to 109.8 + 80.4 ms in patients who received Amiodarone concurrently. No TdP was seen in any patient. We conclude that TH is safe, though careful monitoring of the OTc interval is advisable especially with concurrent use of QT prolonging drugs. |
13,252 | Comparison of CPR outcome predictors between rhythmic abdominal compression and continuous chest compression CPR techniques. | Bystander cardiopulmonary resuscitation (CPR) provides treatment for out-of-hospital cardiac arrest since perfusion of vital organs is critical to resuscitation. Alternatives to standard CPR are evaluated for effectiveness based upon outcome predictive metrics and survival studies. This study focuses on evaluating the performance of rhythmic-only abdominal compression CPR (OAC-CPR) relative to chest compression (CC-CPR) using a complementary suite of mechanistically based CPR outcome predictors. Combined, these predictors provide insight on the transduction of compression-induced pressures into flow perfusing vital organs.</AbstractText>Intrasubject comparisons between the CPR techniques were made during multiple 2-min intervals of induced fibrillation in 17 porcine subjects. Arterial pO2, cardiac output, carotid blood flow, coronary perfusion pressure (CPP), minute alveolar ventilation (MAV), end-tidal CO2, and time from defibrillation to the return of spontaneous circulation (ROSC) were recorded. Organ damage was assessed by necropsy.</AbstractText>Compared with CC-CPR, OAC-CPR had higher pressure and ventilation metrics with increased relative CPP (+16 mm Hg), MAV (+75/ml/min/kg) and a lower reduction in arterial pO2(-22% baseline), but suffered from lower carotid flows (-9.3 ml/min). No significant difference was found comparing cardiac outputs. Furthermore, resuscitation was qualitatively more difficult after OAC-CPR, with a longer time to ROSC (+70 s). No abdominal damage was observed over short periods of OAC-CPR.</AbstractText>Although OAC-CPR appeared superior to CC-CPR by pressure and ventilation metrics, lower carotid flow and longer delay until ROSC raise concerns about overall performance. These paradoxical observations suggest that the evaluation of efficacious alternative CPR techniques may require more direct measurements of vital organ perfusion.</AbstractText>Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.</CopyrightInformation> |
13,253 | Incidence and epidemiology of new onset heart failure with preserved vs. reduced ejection fraction in a community-based cohort: 11-year follow-up of PREVEND. | Differences in clinical characteristics and outcome of patients with established heart failure with preserved ejection fraction (HFpEF) and heart failure with reduced ejection fraction (HFrEF) are well established. Data on epidemiology and prediction of new onset HFpEF, compared with HFrEF, have not been described.</AbstractText>In 8592 subjects of the Prevention of Renal and Vascular End-stage Disease (PREVEND), a community-based, middle-aged cohort study, we performed cause-specific hazard analyses to study the predictive value of risk factors and established cardiovascular biomarkers on new onset HFrEF vs. HFpEF (left ventricular ejection fraction ≤ 40 and ≥ 50%, respectively). A P-value for competing risk (Pcr) <0.10 between HFrEF and HFpEF was considered statistically significant. All potential new onset heart failure cases were reviewed and adjudicated to HFrEF or HFpEF by an independent committee. During a median follow-up of 11.5 years, 374 (4.4%) subjects were diagnosed with heart failure, of which 125 (34%) with HFpEF and 241 (66%) with HFrEF. The average time to diagnosis of new onset HFrEF was 6.6 ± 3.6 years; it was 8.3 ± 3.3 years for HFpEF (P < 0.001). Male gender was associated with new onset HFrEF, whereas female gender with new onset HFpEF (Pcr < 0.001). Higher age and increased N-terminal pro-B-type natriuretic peptide (NT-proBNP) increased the risk for both HFpEF and HFrEF, although for age this was stronger for HFpEF (Pcr = 0.018), whereas NT-proBNP was stronger associated with risk for HFrEF (Pcr = 0.083). Current smokers, increased highly sensitive troponin T, and previous myocardial infarction conferred a significantly increased risk for HFrEF, but not for HFpEF (Pcr = 0.093, 0.091, and 0.061, respectively). Conversely, a history of atrial fibrillation, increased urinary albumin excretion (UAE), and cystatin C were significantly more associated with the risk for HFpEF, but not for HFrEF (Pcr < 0.001, 0.061, and 0.033, respectively). The presence of obesity at baseline was associated with comparable prognostic information for both HFpEF and HFrEF.</AbstractText>Higher age, UAE, cystatin C, and history of atrial fibrillation are strong risk factors for new onset HFpEF. This underscores differential pathophysiological mechanisms for both subtypes of heart failure.</AbstractText> |
13,254 | NTproBNP: an important biomarker in cardiac diseases. | Natriuretic neuropeptides (ANP, BNP, CNP) are produced primarily in the cardiac atria under normal conditions. The main stimulus for ANP and BNP peptide synthesis and secretion is cardiac wall stress. Cardiac ventricular myocytes constitute the major source of BNP-related peptides. Ventricular NT-proBNP production is upregulated in cardiac failure and locally in the area surrounding a myocardial infarct. NT-proBNP is cleared passively by organs with high rate of blood flow (muscle, liver, kidney). It has a longer half life than BNP and higher plasma concentration. BNP and NTproBNP tend to be higher in women and lower in obese individuals. They are also higher in elderly, in left ventricular tachycardia, right ventricular overload, myocardial ischemia, hypoxaemia, renal dysfunction, liver cirrhosis, sepsis and infection. NT-proBNP is useful both in the diagnosis and prognosis of heart failure and is considered to be a gold standard biomarker in heart failure similar to BNP. A cut-off point 300 pg/ml has 99% sensitivity, 60%specificity and NPV 98%for exclusion of acute heart failure. NT proBNP has also a strong prognostic value of death in acute and chronic heart failure and also predicts short and long term mortality in patient with suspected or confirmed unstable CVD. Natriuretic peptides are also prognostic markers for the RV (Right Ventricular) Dysfunction. Their release is due to myocardial stretch from right ventricular pressure overload.Finally, there are data supporting that NT-proBNP might be useful to put a time frame on atrial fibrillation of unknown onset. |
13,255 | Electrocardiographic abnormalities in Trypanosoma cruzi seropositive and seronegative former blood donors. | Blood donor screening leads to large numbers of new diagnoses of Trypanosoma cruzi infection, with most donors in the asymptomatic chronic indeterminate form. Information on electrocardiogram (ECG) findings in infected blood donors is lacking and may help in counseling and recognizing those with more severe disease.</AbstractText>To assess the frequency of ECG abnormalities in T.cruzi seropositive relative to seronegative blood donors, and to recognize ECG abnormalities associated with left ventricular dysfunction.</AbstractText>The study retrospectively enrolled 499 seropositive blood donors in São Paulo and Montes Claros, Brazil, and 483 seronegative control donors matched by site, gender, age, and year of blood donation. All subjects underwent a health clinical evaluation, ECG, and echocardiogram (Echo). ECG and Echo were reviewed blindly by centralized reading centers. Left ventricular (LV) dysfunction was defined as LV ejection fraction (EF)<0.50%.</AbstractText>Right bundle branch block and left anterior fascicular block, isolated or in association, were more frequently found in seropositive cases (p<0.0001). Both QRS and QTc duration were associated with LVEF values (correlation coefficients -0.159,p<0.0003, and -0.142,p = 0.002) and showed a moderate accuracy in the detection of reduced LVEF (area under the ROC curve: 0.778 and 0.790, both p<0.0001). Several ECG abnormalities were more commonly found in seropositive donors with depressed LVEF, including rhythm disorders (frequent supraventricular ectopic beats, atrial fibrillation or flutter and pacemaker), intraventricular blocks (right bundle branch block and left anterior fascicular block) and ischemic abnormalities (possible old myocardial infarction and major and minor ST abnormalities). ECG was sensitive (92%) for recognition of seropositive donors with depressed LVEF and had a high negative predictive value (99%) for ruling out LV dysfunction.</AbstractText>ECG abnormalities are more frequent in seropositive than in seronegative blood donors. Several ECG abnormalities may help the recognition of seropositive cases with reduced LVEF who warrant careful follow-up and treatment.</AbstractText> |
13,256 | A holistic approach to managing a patient with heart failure. | Despite varied and complex therapeutic strategies for managing patients with heart failure, the prognosis may remain poor in certain groups. Recognition that patients with heart failure frequently require input from many care groups formed the basis of The British Society of Heart Failure Annual Autumn Meeting in London (UK), in November 2012, entitled: 'Heart failure: a multidisciplinary approach'. Experts in cardiology, cardiac surgery, general practice, care of the elderly, palliative care and cardiac imaging shared their knowledge and expertise. The 2-day symposium was attended by over 500 participants from the UK, Europe and North America, and hosted physicians, nurses, scientists, trainees and representatives from the industry, as well as patient and community groups. The symposium, accredited by the Royal College of Physicians and the Royal College of Nursing, focused on the multidisciplinary approach to heart failure, in particular, current therapeutic advances, cardiac remodeling, palliative care, atrial fibrillation, heart rate-lowering therapies, management of acute heart failure and the management of patients with mitral regurgitation and heart failure. |
13,257 | Association of fibrosis with mortality and sudden cardiac death in patients with nonischemic dilated cardiomyopathy. | Risk stratification of patients with nonischemic dilated cardiomyopathy is primarily based on left ventricular ejection fraction (LVEF). Superior prognostic factors may improve patient selection for implantable cardioverter-defibrillators (ICDs) and other management decisions.</AbstractText>To determine whether myocardial fibrosis (detected by late gadolinium enhancement cardiovascular magnetic resonance [LGE-CMR] imaging) is an independent and incremental predictor of mortality and sudden cardiac death (SCD) in dilated cardiomyopathy.</AbstractText><AbstractText Label="DESIGN, SETTING, AND PATIENTS" NlmCategory="METHODS">Prospective, longitudinal study of 472 patients with dilated cardiomyopathy referred to a UK center for CMR imaging between November 2000 and December 2008 after presence and extent of midwall replacement fibrosis were determined. Patients were followed up through December 2011.</AbstractText>Primary end point was all-cause mortality. Secondary end points included cardiovascular mortality or cardiac transplantation; an arrhythmic composite of SCD or aborted SCD (appropriate ICD shock, nonfatal ventricular fibrillation, or sustained ventricular tachycardia); and a composite of HF death, HF hospitalization, or cardiac transplantation.</AbstractText>Among the 142 patients with midwall fibrosis, there were 38 deaths (26.8%) vs 35 deaths (10.6%) among the 330 patients without fibrosis (hazard ratio [HR], 2.96 [95% CI, 1.87-4.69]; absolute risk difference, 16.2% [95% CI, 8.2%-24.2%]; P < .001) during a median follow-up of 5.3 years (2557 patient-years of follow-up). The arrhythmic composite was reached by 42 patients with fibrosis (29.6%) and 23 patients without fibrosis (7.0%) (HR, 5.24 [95% CI, 3.15-8.72]; absolute risk difference, 22.6% [95% CI, 14.6%-30.6%]; P < .001). After adjustment for LVEF and other conventional prognostic factors, both the presence of fibrosis (HR, 2.43 [95% CI, 1.50-3.92]; P < .001) and the extent (HR, 1.11 [95% CI, 1.06-1.16]; P < .001) were independently and incrementally associated with all-cause mortality. Fibrosis was also independently associated with cardiovascular mortality or cardiac transplantation (by fibrosis presence: HR, 3.22 [95% CI, 1.95-5.31], P < .001; and by fibrosis extent: HR, 1.15 [95% CI, 1.10-1.20], P < .001), SCD or aborted SCD (by fibrosis presence: HR, 4.61 [95% CI, 2.75-7.74], P < .001; and by fibrosis extent: HR, 1.10 [95% CI, 1.05-1.16], P < .001), and the HF composite (by fibrosis presence: HR, 1.62 [95% CI, 1.00-2.61], P = .049; and by fibrosis extent: HR, 1.08 [95% CI, 1.04-1.13], P < .001). Addition of fibrosis to LVEF significantly improved risk reclassification for all-cause mortality and the SCD composite (net reclassification improvement: 0.26 [95% CI, 0.11-0.41]; P = .001 and 0.29 [95% CI, 0.11-0.48]; P = .002, respectively).</AbstractText>Assessment of midwall fibrosis with LGE-CMR imaging provided independent prognostic information beyond LVEF in patients with nonischemic dilated cardiomyopathy. The role of LGE-CMR in the risk stratification of dilated cardiomyopathy requires further investigation.</AbstractText> |
13,258 | Massive aortic regurgitation following paravalvular balloon valvuloplasty of an Edwards SAPIEN valve treated by emergent CoreValve implantation: never cross a transcatheter aortic valve without a pigtail. | A 72-year-old patient, with a history of coronary artery bypass and aorto-bifemoral graft, was diagnosed with a symptomatic severe aortic valve stenosis in the presence of moderately decreased left ventricular function. The Heart team decision was to implant an Edwards SAPIEN XT 26 mm valve by transapical approach, therefore avoiding access through the aorto-bifemoral graft. At the end of the procedure, grades 2-3 aortic regurgitation was observed. Since each run of rapid pacing ended in ventricular fibrillation, it was decided to treat the aortic regurgitation conservatively with the option of post-dilation in a second procedure if hemodynamic deterioration was observed. Six days later balloon valvuloplasty was performed because of heart failure requiring endotracheal intubation. Despite transesophageal echocardiography guidance the balloon was inadvertently advanced through the paravalvular space. As a consequence, balloon valvuloplasty was complicated by massive aortic regurgitation and severe hemodynamic instability which was resolved after emergency transfemoral implantation of a CoreValve. Without any further complications, the patient was discharged eight days later. |
13,259 | MicroRNA29: a mechanistic contributor and potential biomarker in atrial fibrillation. | Congestive heart failure (CHF) causes atrial fibrotic remodeling, a substrate for atrial fibrillation (AF) maintenance. MicroRNA29 (miR29) targets extracellular matrix proteins. In the present study, we examined miR29b changes in patients with AF and/or CHF and in a CHF-related AF animal model and assessed its potential role in controlling atrial fibrous tissue production.</AbstractText>Control dogs were compared with dogs subjected to ventricular tachypacing for 24 hours, 1 week, or 2 weeks to induce CHF. Atrial miR29b expression decreased within 24 hours in both whole atrial tissue and atrial fibroblasts (-87% and -92% versus control, respectively; p<0.001 for both) and remained decreased throughout the time course. Expression of miR29b extracellular matrix target genes collagen-1A1 (COL1A1), collagen-3A1 (COL3A1), and fibrillin increased significantly in CHF fibroblasts. Lentivirus-mediated miR29b knockdown in canine atrial fibroblasts (-68%; p<0.01) enhanced COL1A1, COL3A1, and fibrillin mRNA expression by 28% (p<0.01), 19% (p<0.05), and 20% (p<0.05), respectively, versus empty virus-infected fibroblasts and increased COL1A1 protein expression by 90% (p<0.05). In contrast, 3-fold overexpression of miR29b decreased COL1A1, COL3A1, and fibrillin mRNA by 65%, 62%, and 61% (all p<0.001), respectively, versus scrambled control and decreased COL1A1 protein by 60% (p<0.05). MiR29b plasma levels were decreased in patients with CHF or AF (by 53% and 54%, respectively; both p<0.001) and were further decreased in patients with both AF and CHF (by 84%; p<0.001). MiR29b expression was also reduced in the atria of chronic AF patients (by 54% versus sinus rhythm; p<0.05). Adenoassociated viral-mediated knockdown of miR29b in mice significantly increased atrial COL1A1 mRNA expression and cardiac tissue collagen content.</AbstractText>MiR29 likely plays a role in atrial fibrotic remodeling and may have value as a biomarker and/or therapeutic target.</AbstractText> |
13,260 | Late outcomes of mitral valve repair for mitral regurgitation due to degenerative disease. | The pathological spectrum of degenerative diseases of the mitral valve (MV) that causes mitral regurgitation (MR) is broad, and there is limited information on late outcomes of MV repair in various subgroups of patients and pathologies. This study examines this issue.</AbstractText>All 840 patients who had MV repair for MR due to degenerative diseases from 1985 to 2004 were prospectively followed with clinical and echocardiographic evaluations at biennial intervals up to 26 years, median of 10.4 years. Clinical, hemodynamic, and pathological variables were evaluated for their association with outcomes. Age, left ventricular ejection fraction, and functional class were predictors of late cardiac- and valve-related deaths by multivariable analysis. MV repair failed to restore life span to normal in patients with functional class IV. Thirty-eight patients had repeat MV surgery, and the probability of reoperation at 20 years was 5.9%. During the follow-up, recurrent severe MR developed in 37 patients, and moderate MR developed in 61. Age, isolated prolapse of the anterior leaflet, the degree of myxomatous changes in the MV, lack of mitral annuloplasty, and duration of cardiopulmonary bypass were associated with increased risk of recurrent MR. At 20 years, the freedom from recurrent severe MR was 90.7%, and the freedom from moderate or severe MR was 69.2%.</AbstractText>MV repair for degenerative MR restored life span to normal except in patients with symptoms at rest and impaired left ventricular function. Advanced age and complex mitral valve pathologies increased the risk of late recurrent MR.</AbstractText> |
13,261 | Bifurcation theory and cardiac arrhythmias. | In this paper we review two types of dynamic behaviors defined by the bifurcation theory that are found to be particularly useful in describing two forms of cardiac electrical instabilities that are of considerable importance in cardiac arrhythmogenesis. The first is action potential duration (APD) alternans with an underlying dynamics consistent with the period doubling bifurcation theory. This form of electrical instability could lead to spatially discordant APD alternans leading to wavebreak and reentrant form of tachyarrhythmias. Factors that modulate the APD alternans are discussed. The second form of bifurcation of importance to cardiac arrhythmogenesis is the Hopf-homoclinic bifurcation that adequately describes the dynamics of the onset of early afterdepolarization (EAD)-mediated triggered activity (Hopf) that may cause ventricular tachycardia and ventricular fibrillation (VT/VF respectively). The self-termination of the triggered activity is compatible with the homoclinic bifurcation. Ionic and intracellular calcium dynamics underlying these dynamics are discussed using available experimental and simulation data. The dynamic analysis provides novel insights into the mechanisms of VT/VF, a major cause of sudden cardiac death in the US. |
13,262 | Thyrotoxicosis-facilitated bridge to recovery with a continuous-flow left ventricular assist device. | The HeartMate II is a continuous-flow left ventricular assist device that can be explanted from patients after cardiac recovery. We implanted a HeartMate II in a 21-year-old man who had idiopathic cardiomyopathy. A year later, he developed thyrotoxicosis, presumably secondary to amiodarone administered for ventricular fibrillation. Four months after the diagnosis of thyrotoxicosis, thyroid hormone levels had returned to normal, and native cardiac function had improved remarkably. After a support period of 24 months, the HeartMate II was explanted. Six years later, the patient continues to be in New York Heart Association functional Class I. Amiodarone-induced thyrotoxicosis may have contributed to myocardial recovery. |
13,263 | The effects of an automatic, low pressure and constant flow ventilation device versus manual ventilation during cardiovascular resuscitation in a porcine model of cardiac arrest. | Cardiac arrest is an important cause of mortality. Cardiopulmonary resuscitation (CPR) improves survival, however, delivery of effective CPR can be challenging and combining effective chest compressions with ventilation, while avoiding over-ventilation is difficult. We hypothesized that ventilation with a pneumatically powered, automatic ventilator (Oxylator(®)) can provide adequate ventilation in a model of cardiac arrest and improve the consistency of ventilations during CPR.</AbstractText><AbstractText Label="METHODS/RESULTS" NlmCategory="RESULTS">Twelve pigs (∼40 kg, either sex) underwent 3 episodes each of cardiac arrest and resuscitation consisting of 30s of untreated ventricular fibrillation, followed by 5 min of CPR, defibrillation, and ∼30 min of recovery. During CPR in each episode, pigs were ventilated in 1 of 3 ways in random balanced order: manual ventilation using AMBU bag (12 breaths/min), low pressure Oxylator(®) (maximum airway pressure 15 cm H2O with 20 L/min constant flow in automatic mode [Ox15/20]), or high pressure Oxylator(®) (maximum airway pressure 20 cm H2O with 30 L/min constant flow in automatic mode [Ox20/30]). During CPR, both Ox15/20 and Ox20/30 resulted in higher levels of positive end expiratory pressure than manual ventilation. Ox15/20 ventilation also resulted in higher arterial pCO2 than manual ventilation. Ox20/30 ventilation yielded higher arterial pO2 and a lower arterial-alveolar gradient than manual ventilation. All pigs were successfully defibrillated, and no measured haemodynamic variables were different between the groups.</AbstractText>Ventilation with an automatic ventilation device during CPR is feasible and provides adequate ventilation and comparable haemodynamics when compared to manual bag ventilation.</AbstractText>Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
13,264 | Two dosing regimens of tosedostat in elderly patients with relapsed or refractory acute myeloid leukaemia (OPAL): a randomised open-label phase 2 study. | Tosedostat is a novel oral aminopeptidase inhibitor with clinical activity in a previous phase 1-2 study in elderly patients with relapsed or refractory acute myeloid leukaemia (AML). We aimed to compare two dosing regimens of tosedostat.</AbstractText>In this randomised phase 2 study, patients aged 60 years or older with AML that had relapsed after a first complete remission lasting less than 12 months, or had achieved no previous complete remission, were randomly assigned (1:1) to receive as first salvage tosedostat 120 mg once daily for 6 months or 240 mg once daily for 2 months followed by 120 mg for 4 months. Randomisation was by block method via an interactive web response system using a randomisation schedule generated by an external vendor, with no stratification. The study was open label. The primary endpoint was the proportion of patients who obtained a complete remission or complete remission with incomplete platelet recovery. Analyses included all patients randomly assigned to treatment groups who received at least one oral dose of tosedostat. The study is registered with ClinicalTrials.gov, number NCT00780598.</AbstractText>38 patients were randomly assigned to receive tosedostat 120 mg and 38 to receive the tosedostat 240 mg to 120 mg regimen. 38 patients in the 120 mg group and 35 in the 240 mg to 120 mg group received tosedostat. Seven patients (10%) had complete remission or complete remission with incomplete platelet recovery: two (5%) in the 120 mg group and five (14%) in the 240 mg to 120 mg group. The most common grade 3 or worse adverse events were febrile neutropenia (11 [29%] patients in the 120 mg group and ten [29%] of the 240 mg to 120 mg group), thrombocytopenia (eight [21%] and eight [23%] patients), fatigue (seven [18%] and eight [23%] patients), dyspnoea (five [13%] and seven [20%] patients), and pneumonia (four [11%] and six [17%] patients). There were five fatal adverse events deemed to be treatment-related: three in the 120 mg group and two in the 240 mg to 120 mg group. The events were acute hepatitis, respiratory failure, pneumonia, atrial fibrillation, and left ventricular dysfunction.</AbstractText>Tosedostat, at either dose schedule, has activity in older patients with relapsed or refractory AML. Additional studies of tosedostat including combination with hypomethylating agents and low-dose cytarabine in patients with high-risk myelodysplastic syndromes and AML are ongoing or planned.</AbstractText>Chroma Therapeutics.</AbstractText>Copyright © 2013 Elsevier Ltd. All rights reserved.</CopyrightInformation> |
13,265 | Usefulness of electrocardiographic frontal QRS-T angle to predict increased morbidity and mortality in patients with chronic heart failure. | The risk of death in heart failure (HF) is high. The electrocardiographic spatial QRS-T angle reflects changes in the direction of the repolarization sequence and predicts death in the general population. The frontal QRS-T angle is simple to measure but has not been evaluated in a large chronic HF cohort. We examined the significance of the frontal QRS-T angle in predicting the clinical outcome in a large cohort of patients with HF. The QRS-T angle was calculated from the frontal QRS and T axis of the baseline 12-lead surface electrocardiogram. The patients were followed for cardiac-related hospitalizations and death; 5,038 patients with HF were evaluated. The mean follow-up period was 576 days; 51% were men. Overall survival during the follow-up period was 83%. Cox regression analysis after adjustment for significant predictors, including age, gender, ischemic heart disease, hypertension, atrial fibrillation, body mass index, pulse, serum hemoglobin, sodium, estimated glomerular filtration rate, and urea levels, demonstrated that the QRS-T angle was an incremental predictor of increased mortality in both genders. For women, a QRS-T angle of ≥60° had a hazard ratio of 1.35 (95% confidence interval 1.04 to 1.75; p <0.05) and a QRS-T angle of ≥120° had a hazard ratio of 1.45 (95% confidence interval 1.10 to 1.92, p <0.01). For men, a QRS-T angle of ≥130° had a hazard ratio of 1.53 (95% confidence interval 1.14 to 2.06, p <0.01). For the whole cohort, a QRS-T angle of ≥125° gave a hazard ratio of 1.47 (95% confidence interval 1.20 to 1.80, p <0.0001). The QRS-T angle was also a predictor of increased cardiac-related hospitalizations. The QRS-T angle was a predictor in patients with reduced and preserved left ventricular function and in patients with a normal QRS interval. In conclusion, the QRS-T angle was a powerful predictor of outcome in patients with HF. We believe the QRS-T angle should be a part of the electrocardiographic evaluation of patients with HF. |
13,266 | Intracellular lactate signaling cascade in atrial remodeling of mitral valvular patients with atrial fibrillation. | Atrial remodeling has emerged as the structural basis for the maintenance and recurrence of atrial fibrillation. Lactate signaling cascade was recently linked to some cardiovascular disorders for its regulatory functions to myocardial structural remodeling. It was hypothesized that lactate signaling cascade was involved in the maintenance and recurrence of atrial fibrillation by regulating atrial structural remodeling.</AbstractText>Biopsies of right atrial appendage and clinical data were collected from sex- and age-matched 30 persistent atrial fibrillation, 30 paroxysmal atrial fibrillation, 30 sinus rhythm patients undergoing isolated mitral valve surgery and 10 healthy heart donors.</AbstractText>Atrial fibrillation groups had higher atrial lactate expression and this upregulated expression was positively correlated with regulatory indicators of atrial structural remodeling as reflected by severe oxidative stress injury and mitochondrial control of apoptosis.</AbstractText>The present findings suggest a potential role for lactate signaling cascade in the maintenance and recurrence of atrial fibrillation and possibly represent new targets for therapeutic intervention in this disorder.</AbstractText> |
13,267 | Non-alcoholic fatty liver disease is associated with an increased incidence of atrial fibrillation in patients with type 2 diabetes. | The relationship between non-alcoholic fatty liver disease (NAFLD) and atrial fibrillation (AF) in type 2 diabetes is currently unknown. We examined the relationship between NAFLD and risk of incident AF in people with type 2 diabetes.</AbstractText>We prospectively followed for 10 years a random sample of 400 patients with type 2 diabetes, who were free from AF at baseline. A standard 12-lead electrocardiogram was undertaken annually and a diagnosis of incident AF was confirmed in affected participants by a single cardiologist. At baseline, NAFLD was defined by ultrasonographic detection of hepatic steatosis in the absence of other liver diseases. During the 10 years of follow-up, there were 42 (10.5%) incident AF cases. NAFLD was associated with an increased risk of incident AF (odds ratio [OR] 4.49, 95% CI 1.6-12.9, p<0.005). Adjustments for age, sex, hypertension and electrocardiographic features (left ventricular hypertrophy and PR interval) did not attenuate the association between NAFLD and incident AF (adjusted-OR 6.38, 95% CI 1.7-24.2, p = 0.005). Further adjustment for variables that were included in the 10-year Framingham Heart Study-derived AF risk score did not appreciably weaken this association. Other independent predictors of AF were older age, longer PR interval and left ventricular hypertrophy.</AbstractText>Our results indicate that ultrasound-diagnosed NAFLD is strongly associated with an increased incidence of AF in patients with type 2 diabetes even after adjustment for important clinical risk factors for AF.</AbstractText> |
13,268 | Hypothermia for neuroprotection in children after cardiopulmonary arrest. | Cardiopulmonary arrest in paediatric patients often results in death or survival with severe brain injury. Therapeutic hypothermia, lowering of the core body temperature to 32°C to 34°C, may reduce injury to the brain in the period after the circulation has been restored. This therapy has been effective in neonates with hypoxic ischaemic encephalopathy and adults after witnessed ventricular fibrillation cardiopulmonary arrest. The effect of therapeutic hypothermia after cardiopulmonary arrest in paediatric patients is unknown.</AbstractText>To assess the clinical effectiveness of therapeutic hypothermia after paediatric cardiopulmonary arrest.</AbstractText>We searched the Cochrane Anaesthesia Review Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 11); Ovid MEDLINE (1966 to December 2011); Ovid EMBASE (1980 to December 2011); Ovid CINAHL (1982 to December 2011); Ovid BIOSIS (1923 to December 2011); and Web of Science (1945 to December 2011). We searched the trials registry databases for ongoing trials. We also contacted international experts in therapeutic hypothermia and paediatric critical care to locate further published and unpublished studies.</AbstractText>We planned to include randomized and quasi-randomized controlled trials comparing therapeutic hypothermia with normothermia or standard care in children, aged 24 hours to 18 years, after paediatric cardiopulmonary arrest.</AbstractText>Two authors independently assessed articles for inclusion.</AbstractText>We found no studies that satisfied the inclusion criteria. We found four on-going randomized controlled trials which may be available for analysis in the future. We excluded 18 non-randomized studies. Of these 18 non-randomized studies, three compared therapeutic hypothermia with standard therapy and demonstrated no difference in mortality or the proportion of children with a good neurological outcome; a narrative report was presented.</AbstractText><AbstractText Label="AUTHORS' CONCLUSIONS" NlmCategory="CONCLUSIONS">Based on this review, we are unable to make any recommendations for clinical practice. Randomized controlled trials are needed and the results of on-going trials will be assessed when available.</AbstractText> |
13,269 | United Kingdom national experience of entirely subcutaneous implantable cardioverter-defibrillator technology: important lessons to learn. | The aim of this study was to describe the early phase United Kingdom (UK) clinical experience with a novel entirely subcutaneous implantable cardioverter-defibrillator (S-ICD).</AbstractText>A questionnaire was sent to all UK hospitals implanting S-ICDs. Nineteen of 25 (76%) hospitals responded with the details of 111 implanted patients [median 5/hospital (range 1-18)]. Mean duration of follow-up was 12.7 ± 7.1 months. Median patient age was 33 years (range 10-87 years). Underlying pathology was primary electrical disease in 43%, congenital heart disease 12%, hypertrophic cardiomyopathy 20%, ischaemic cardiomyopathy 14%, idiopathic dilated cardiomyopathy 5%, and other cardiomyopathies 7% patients. Nineteen (17%) patients required 20 re-operations, including permanent device explantation in 10 (9%). Twenty-four appropriate shocks were delivered in 13 (12%) patients, including 10 for ventricular fibrillation. One patient suffered arrhythmic death, but there were no failures to detect or terminate ventricular arrhythmias above the programmed detection rate. Fifty-one inappropriate shocks were delivered in 17 (15%) patients. Forty-one (80%) were for T-wave over-sensing and 1 (2%) for atrial flutter-wave over-sensing. The 11 patients who received inappropriate shocks due to T-wave over-sensing were significantly younger than patients who did not (24 ± 10 vs. 37 ± 19 years; P = 0.02).</AbstractText>The S-ICD is an important innovation in ICD technology. However, these data indicate that adverse event rates are significant during early clinical adoption. Important lessons in patient selection, implant technique, and device programming can be learnt from this experience.</AbstractText> |
13,270 | Noninvasive electrocardiographic imaging of arrhythmogenic substrates in humans. | Cardiac excitation is determined by interactions between the source of electric activation (membrane depolarization) and the load that cardiac tissue presents. This relationship is altered in pathology by remodeling processes that often create a substrate favoring the development of cardiac arrhythmias. Most studies of arrhythmia mechanisms and arrhythmogenic substrates have been conducted in animal models, which may differ in important ways from the human pathologies they are designed to represent. Electrocardiographic imaging is a noninvasive method for mapping the electric activity of the heart in humans in real-world conditions. This review summarizes results from electrocardiographic imaging studies of arrhythmogenic substrates associated with human clinical arrhythmias. Examples include heart failure, myocardial infarction scar, atrial fibrillation, and abnormal ventricular repolarization. |
13,271 | Rotors and the dynamics of cardiac fibrillation. | The objective of this article is to present a broad review of the role of cardiac electric rotors and their accompanying spiral waves in the mechanism of cardiac fibrillation. At the outset, we present a brief historical overview regarding reentry and then discuss the basic concepts and terminologies pertaining to rotors and their initiation. Thereafter, the intrinsic properties of rotors and spiral waves, including phase singularities, wavefront curvature, and dominant frequency maps, are discussed. The implications of rotor dynamics for the spatiotemporal organization of fibrillation, independent of the species being studied, are described next. The knowledge gained regarding the role of cardiac structure in the initiation or maintenance of rotors and the ionic bases of spiral waves in the past 2 decades, as well as the significance for drug therapy, is reviewed subsequently. We conclude by examining recent evidence suggesting that rotors are critical in sustaining both atrial and ventricular fibrillation in the human heart and its implications for treatment with radiofrequency ablation. |
13,272 | A reliable witness: dual-chamber pacemaker prolonged intracardiac recordings of a resuscitated cardiac arrest episode. | We report the case of a patient with a previously implanted pacemaker, who suffered cardiac arrest due to ventricular fibrillation requiring cardiopulmonary resuscitation (CPR) manoeuvres and electrical cardioversion to restore sinus rhythm. Analysis of the pacemaker's stored electrograms showed the arrhythmia progression from monomorphic ventricular tachycardia to ventricular fibrillation and the electrophysiological effects of CPR manoeuvres and epinephrine administration before successful cardioversion. |
13,273 | Feasibility of absolute cerebral tissue oxygen saturation during cardiopulmonary resuscitation. | Current monitoring during cardiopulmonary resuscitation (CPR) is limited to clinical observation of consciousness, breathing pattern and presence of a pulse. At the same time, the adequacy of cerebral oxygenation during CPR is critical for neurological outcome and thus survival. Cerebral oximetry, based on near-infrared spectroscopy (NIRS), provides a measure of brain oxygen saturation. Therefore, we examined the feasibility of using NIRS during CPR.</AbstractText>Recent technologies (FORE-SIGHT™ and EQUANOX™) enable the monitoring of absolute cerebral tissue oxygen saturation (SctO2) values without the need for pre-calibration. We tested both FORE-SIGHT™ (five patients) and EQUANOX Advance™ (nine patients) technologies in the in-hospital as well as the out-of-hospital CPR setting. In this observational study, values were not utilized in any treatment protocol or therapeutic decision. An independent t-test was used for statistical analysis.</AbstractText>Our data demonstrate the feasibility of both technologies to measure cerebral oxygen saturation during CPR. With the continuous, pulseless near-infrared wave analysis of both FORE-SIGHT™ and EQUANOX™ technology, we obtained SctO2 values in the absence of spontaneous circulation. Both technologies were able to assess the efficacy of CPR efforts: improved resuscitation efforts (improved quality of chest compressions with switch of caregivers) resulted in higher SctO2 values. Until now, the ability of CPR to provide adequate tissue oxygenation was difficult to quantify or to assess clinically due to a lack of specific technology. With both technologies, any change in hemodynamics (for example, ventricular fibrillation) results in a reciprocal change in SctO2. In some patients, a sudden drop in SctO2 was the first warning sign of reoccurring ventricular fibrillation.</AbstractText>Both the FORE-SIGHT™ and EQUANOX™ technology allow non-invasive monitoring of the cerebral oxygen saturation during CPR. Moreover, changes in SctO2 values might be used to monitor the efficacy of CPR efforts.</AbstractText> |
13,274 | A Case of Breathlessness during Pregnancy: The Difficulty in Diagnosing Heart Failure. | We present the case of a 33-year-old woman in her second pregnancy who was transferred to our unit following a one-month history of worsening fatigue and a three-day history of worsening symptoms of heart failure. Shortly after presentation she developed ventricular fibrillation and arrested. At an emergency caesarean section a placental abruption was noted and the baby was stillborn, unable to be resuscitated. The patient required a prolonged intensive and coronary care stay. Echocardiographic findings were consistent with dilated cardiomyopathy and as all investigations to ascertain a cause were negative she was diagnosed with peripartum cardiomyopathy. Her case highlights a potential fatal cause of breathlessness during pregnancy and the role of B-type natriuretic peptide to assist in the differential diagnosis of these cases. |
13,275 | Current Concepts of Premature Ventricular Contractions. | Premature ventricular contractions (PVCs) are early depolarizations of the myocardium originating in the ventricle. PVCs are common with an estimated prevalence of 40% to 75% in the general population on 24- to 48-hour Holter monitoring. Traditionally, they have been thought to be relatively benign in the absence of structural heart disease but they represent increased risk of sudden death in structural heart disease. Especially in ischemic heart disease, the frequency and complexity of PVCs is associated with mortality. Implantable cardioverter defibrillator therapy is indicated in patients with nonsustained ventricular tachycardia (NSVT) due to prior myocardial infarction, left ventricular ejection fraction less than or equal to 40%, and inducible ventricular fibrillation or sustained ventricular tachycardia at electrophysiological study. In congestive heart failure, PVCs did not provide significant incremental prognostic information beyond readily available clinical variables. Consequently, NSVT should not guide therapeutic interventions. Recently, the concept of PVC-induced cardiomyopathy was proposed when pharmacological suppression of PVCs in patients with presumed idiopathic dilated cardiomyopathy subsequently showed improved left ventricular systolic dysfunction. For the treatment PVCs, it is important to consider underlying heart disease, the frequency of the PVCs and the frequency and severity of symptoms. |
13,276 | Amiodarone-induced destructive thyroiditis associated with coronary artery vasospasm and recurrent ventricular fibrillation. | A 55-year-old male on long-term amiodarone therapy presented with ischaemic chest pain and recurrent unwitnessed syncope. Interrogation of his internal cardiac defibrillator, which had been inserted 4 years earlier, revealed two episodes of ventricular fibrillation, the timing of which corresponded to his syncopal events. Severe spontaneous coronary artery vasospasm was observed on coronary angiogram. Thyroid function testing revealed severe hyperthyroidism with a diagnosis of type 2 amiodarone-induced thyrotoxicosis (AIT) subsequently made. Treatment with prednisolone therapy was commenced and thyroid function rapidly normalized. Prednisolone was weaned without recurrence of hyperthyroidism and on last review, 6 months after initial presentation, he remains free from further chest pain and arrhythmias. Our patient's presentation is a very rare case of AIT-associated coronary artery spasm and documented ischaemic ventricular fibrillation with fortunate survival. |
13,277 | QRS complex duration enhancement as ventricular late potential indicator by signal-averaged ECG using time-amplitude alignments. | Ventricular late potentials (VLPs) are small-amplitude waves with a short duration that appear at the end part of the QRS complex, making a QRS complex duration larger. The signal-averaged electrocardiography (ECG) technique enhances VLPs and beats, assuming noise as the only random variable. However, ECG signals are not completely stationary and different elongations appear in both time and amplitude in each beat. This research proposes to use piecewise linear approximation to segment each beat and performs the alignment of the beats using the technique known as derivative dynamic time-warping to have beats better aligned and consequently enhance the presence of VLPs. We recorded high-resolution ECGs (HRECGs) from 50 subjects in supine position with no heart-stroke antecedents. VLPs were created synthetically and added to the HRECGs. Two cases were evaluated: (i) duration of the QRS complexes with VLPs without beats alignment, and (ii) duration of QRS complexes with VLPs using beats alignment in time and amplitude. Considering QRS duration as an indicative of VLP presence, results show that when using beats alignment in time and amplitude it is possible to reach a sensitivity of 0.96 and a specificity of 0.52, as opposed to 0.72 and 0.40, respectively, when using only averaging without beats alignment in time and amplitude. |
13,278 | An accordion not to be played. | We present the case of a 52-year-old man with normal coronary arteries admitted to our department after being resuscitated from ventricular fibrillation. Transthoracic echocardiography raised suspicion of left-ventricular non-compaction. Cardiac magnetic resonance excluded this, but showed several systolic bulgings of the right ventricle and a characteristic focal 'crinkling' of the right-ventricular outflow tract known as the 'accordion' sign, a specific marker of desmosomal gene mutations, thus suggesting the presence of an arrhythmogenic cardiomyopathy. Extensive mid-myocardial late gadolinium enhancement and fatty infiltration, predominantly of the left ventricle, finally confirmed the diagnosis of left dominant arrhythmogenic cardiomyopathy, a rare variant of arrhythmogenic right-ventricular cardiomyopathy. |
13,279 | KCNJ2 mutation in short QT syndrome 3 results in atrial fibrillation and ventricular proarrhythmia. | We describe a mutation (E299V) in KCNJ2, the gene that encodes the strong inward rectifier K(+) channel protein (Kir2.1), in an 11-y-old boy. The unique short QT syndrome type-3 phenotype is associated with an extremely abbreviated QT interval (200 ms) on ECG and paroxysmal atrial fibrillation. Genetic screening identified an A896T substitution in a highly conserved region of KCNJ2 that resulted in a de novo mutation E299V. Whole-cell patch-clamp experiments showed that E299V presents an abnormally large outward IK1 at potentials above -55 mV (P < 0.001 versus wild type) due to a lack of inward rectification. Coexpression of wild-type and mutant channels to mimic the heterozygous condition still resulted in a large outward current. Coimmunoprecipitation and kinetic analysis showed that E299V and wild-type isoforms may heteromerize and that their interaction impairs function. The homomeric assembly of E299V mutant proteins actually results in gain of function. Computer simulations of ventricular excitation and propagation using both the homozygous and heterozygous conditions at three different levels of integration (single cell, 2D, and 3D) accurately reproduced the electrocardiographic phenotype of the proband, including an exceedingly short QT interval with merging of the QRS and the T wave, absence of ST segment, and peaked T waves. Numerical experiments predict that, in addition to the short QT interval, absence of inward rectification in the E299V mutation should result in atrial fibrillation. In addition, as predicted by simulations using a geometrically accurate three-dimensional ventricular model that included the His-Purkinje network, a slight reduction in ventricular excitability via 20% reduction of the sodium current should increase vulnerability to life-threatening ventricular tachyarrhythmia. |
13,280 | Tachycardia detection performance of implantable loop recorders: results from a large 'real-life' patient cohort and patients with induced ventricular arrhythmias. | Implantable loop recorders (ILRs) are valuable for diagnosing arrhythmias. We evaluated tachycardia detection performance of the Medtronic Reveal(®) ILR with FullView™ Software.</AbstractText>The rate of occurrence of tachycardia detection [supraventricular tachycardia, ventricular tachycardia (VT), and ventricular fibrillation (VF)] and the percentage of appropriately detected tachycardias were determined from all 2190 ILR patients that transmitted to CareLink over a 4-month period (total follow-up = 135.6 patient-years). All 1909 tachycardia episodes were reviewed. Episodes with actual heart rate above the programmed tachycardia detection rate were classified as appropriate. Sensitivity to detect true ventricular arrhythmias was assessed in another group of 215 patients undergoing implantable cardioverter defibrillator (ICD) implant testing. Skin electrodes represented ILR electrodes. Induced VF (404 episodes) and VT (93 episodes) were processed by an emulation of FullView Software. Generalized estimation equation analysis adjusted for multiple episodes per patient. In the CareLink cohort, 68.7% (63.9% adjusted) of detected episodes had tachycardia above the detection rate. Of 1642 episodes detected in the VT zone (12.1 episodes/patient-year), 78.8% (79.0% adjusted) had tachycardia above the detection rate. Of 267 episodes detected in the fast VT zone (1.9 episodes/patient-year), 6.7% (9.4% adjusted) had tachycardia above the detection rate. Twelve true VT/VF episodes were observed in 10 patients. In the ICD patient cohort, 95.9% (96.5% adjusted) of induced VT/VF segments were correctly detected at nominal rate cutoffs. When VT detection was set to 130 b.p.m. (to include the slowest VT), 99.0% (99.3% adjusted) were correctly detected.</AbstractText>The majority (63.9%) of detected tachycardias contained true tachycardia. Sensitivity to detect induced VT/VF was 99.3%.</AbstractText> |
13,281 | Identification of high-risk Brugada syndrome patients by combined analysis of late potential and T-wave amplitude variability on ambulatory electrocardiograms. | Risk stratification is important in the management of Brugada syndrome (BrS). Late potentials (LPs) and T-wave amplitude variability (TAV) in high-resolution ambulatory electrocardiography (ECG) were retrospectively investigated.</AbstractText>One hundred and twenty-seven patients diagnosed with BrS on 12-lead ECG were classified into 3 groups: documented ventricular fibrillation (VF)/asystole (n=19), episodes of syncope alone (n=30), and asymptomatic (n=78). Healthy volunteers were enrolled as controls (n=25). In the BrS patients, LPs showed appreciable circadian periodicity; filtered QRS duration (fQRS) and duration of the terminal low-amplitude signal <40 μV (LAS40) increased, whereas root mean square voltage of the terminal 40 ms of the fQRS (RMS40) decreased at night compared with the day. TAV did not have such a circadian periodicity. LP-positive incidence (night-time) and peak TAV were as follows: VF/asystole>syncope/asymptomatic>control (P<0.001). VF/asystole was discriminated from control at a ratio of 81-84% by night-time LPs (fQRS >116 ms, LAS40 >35 ms, RMS40 <25 μV) or peak TAV (>54 μV); VF/asystole was discriminated from syncope/asymptomatic at a ratio of 60-69%, by night-time LPs (fQRS >122 ms, LAS40 >42 ms, RMS40 <18μV) or peak TAV (>58 μV). Combined analysis of LPs and peak TAV increased the discriminant ratio up to 93% and 77%, respectively.</AbstractText>Analysis of both LPs and TAV (taking circadian periodicity into account) is useful in identification of high-risk BrS patients. </AbstractText> |
13,282 | Effect of nifedipine versus telmisartan on prevention of atrial fibrillation recurrence in hypertensive patients. | It is controversial whether angiotensin II receptor blockers provide better protection than calcium antagonists against atrial fibrillation (AF) recurrence in hypertensive patients. This study was designed to compare the effect of nifedipine- and telmisartan-based antihypertensive treatments for preventing AF recurrence in hypertensive patients with paroxysmal AF. A total of 149 hypertensive patients with paroxysmal AF were randomized to nifedipine- or telmisartan-based antihypertensive treatment groups. The target blood pressure (BP) was <130/80 mm Hg. Clinic BP, ECG, Holter monitoring, and echocardiography were followed up for 2 years. The primary end point was the incidence of overall and persistent AF recurrence. During follow-up, there was no statistical difference in the rate of patients lowering to target BP between both groups, whereas nifedipine group had slightly better BP control but similar heart rate control at 24 months. The incidence of AF recurrence was similar in both groups (nifedipine versus telmisartan: 58.7% versus 55.4%; P=0.742), and Kaplan-Meier analysis showed no significant difference in the freedom from AF recurrence (log-rank test; P=0.48). However, the rate of developing persistent AF in telmisartan group was lower than that in nifedipine group (5.4% versus 16.0%; P=0.035). Patients in telmisartan group had lower values of left atrial diameter, left atrial volume index, and left ventricular mass index at the end of follow-up. The effects of telmisartan in preventing AF recurrences in hypertensive patients with paroxysmal AF after intensive lowering BP is similar to that of nifedipine, but telmisartan has more potent effects on preventing progression to persistent AF. |
13,283 | Shorter height is related to lower cardiovascular disease risk - a narrative review. | Numerous Western studies have shown a negative correlation between height and cardiovascular disease. However, these correlations do not prove causation. This review provides a variety of studies showing short people have little to no cardiovascular disease. When shorter people are compared to taller people, a number of biological mechanisms evolve favoring shorter people, including reduced telomere shortening, lower atrial fibrillation, higher heart pumping efficiency, lower DNA damage, lower risk of blood clots, lower left ventricular hypertrophy and superior blood parameters. The causes of increased heart disease among shorter people in the developed world are related to lower income, excessive weight, poor diet, lifestyle factors, catch-up growth, childhood illness and poor environmental conditions. For short people in developed countries, the data indicate that a plant-based diet, leanness and regular exercise can substantially reduce the risk of cardiovascular disease. |
13,284 | High-dose argatroban for heparin-induced thrombocytopenia in a child using a ventricular assist device. | A 10-year-old boy who was receiving support from a ventricular assist device (VAD) experienced heparin-induced thrombocytopenia that was successfully treated with high-dose argatroban infusion to attain therapeutic activated partial thromboplastin time in spite of high serum argatroban levels. This case also highlights bolus argatroban dosing for VAD change in the setting of persistent ventricular fibrillation. |
13,285 | Use of asymmetric bidirectional catheters with different curvature radius for catheter ablation of cardiac arrhythmias. | The impact of recently introduced asymmetric bidirectional ablation catheters on procedural parameters and acute success rates of ablation procedures is unknown.</AbstractText>We retrospectively analyzed data regarding ablations using a novel bidirectional catheter in a tertiary cardiac center and compared these in 1:5 ratio with a control group of procedures matched for age, gender, operator, and ablation type.</AbstractText>A total of 50 cases and 250 controls of median age 60 (50-68) years were studied. Structural heart disease was equally prevalent in both groups (39%) while history of previous ablations was more common in the study arm (54% vs 30%, P = 0.001). Most of the ablation cases were for atrial fibrillation (46%), followed by atrial tachycardia (28%), supraventricular tachycardia (12%), and ventricular tachycardia (14%). Median procedure duration was 128 (52-147) minutes with the bidirectional, versus 143 (105-200) minutes with the conventional catheter (P = 0.232), and median fluoroscopy time was 17 (10-34) minutes versus 23 (12-39) minutes, respectively (P = 0.988). There was a trend toward a lower procedure duration for the atrial tachycardia ablations, 89 (52-147) minutes versus 130 (100-210) minutes, P = 0.064. The procedure was successfully completed in 96% of the bidirectional versus 84% of the control cases (P = 0.151). A negative correlation was observed between the relative fluoroscopy duration and the case number (r = -0.312, P = 0.028), reflecting the learning curve for the bidirectional catheter.</AbstractText>The introduction of the bidirectional catheter resulted in no prolongation of procedure parameters and similar success rates, while there was a trend toward a lower procedure duration for atrial tachycardia ablations.</AbstractText>©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.</CopyrightInformation> |
13,286 | Wenxin Keli suppresses ventricular triggered arrhythmias via selective inhibition of late sodium current. | Wenxin Keli is a popular Chinese herb extract that approximately five million Asians are currently taking for the treatment of a variety of ventricular arrhythmias. However, its electrophysiological mechanisms remain poorly understood.</AbstractText>The concentration-dependent electrophysiological effects of Wenxin Keli were evaluated in the isolated rabbit left ventricular myocytes and wedge preparation. Wenxin Keli selectively inhibited late sodium current (INa) with an IC50 of 3.8 ± 0.4 mg/mL, which was significantly lower than the IC50 of 10.6 ± 0.9 mg/mL (n = 6, P < 0.05) for the fast INa. Wenxin Keli produced a small but statistically significant QT prolongation at 0.3 mg/mL, but shortened the QT and Tp-e interval at concentrations ≥ 1 mg/mL. Wenxin Keli increased QRS duration by 10.1% from 34.8 ± 1.0 ms to 38.3 ± 1.1 ms (n = 6, P < 0.01) at 3 mg/mL at a basic cycle length of 2,000 ms. However, its effect on the QRS duration exhibited weak use-dependency, that is, QRS remained less changed at increased pacing rates than other classic sodium channel blockers, such as flecainide, quinidine, and lidocaine. On the other hand, Wenxin Keli at 1-3 mg/mL markedly reduced dofetilide-induced QT and Tp-e prolongation by attenuation of its reverse use-dependence and abolished dofetilide-induced early afterdepolarization (EAD) in four of four left ventricular wedge preparations. It also suppressed digoxin-induced delayed after depolarization (DAD) and ventricular tachycardias without changing the positive staircase pattern in contractility at 1-3 mg/mL in a separate experimental series (four of four).</AbstractText>Wenxin Keli suppressed EADs, DADs, and triggered ventricular arrhythmias via selective inhibition of late INa.</AbstractText>©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.</CopyrightInformation> |
13,287 | A prospective study comparing the sensed R wave in bipolar and extended bipolar configurations: the PropR study. | Progress in implantable cardiac defibrillator (ICD) technology has allowed for switching the sensing polarity for the detection of ventricular fibrillation (VF). However, whether one sensing polarity confers additional advantage over the other is not known.</AbstractText>To determine whether one sensing polarity is superior to the other for the detection of VF.</AbstractText>Patients were enrolled into a prospective randomized study of sensing of VF and R waves in normal rhythm. Sensing of VF was determined by number of under sensed beats (USB), and time to detection of VF (TDVF). Each patient underwent ICD implantation followed by testing of the ICD. At each induction, patients were randomized to sensing in extended bipolar (EBP) or true bipolar (TBP) configuration. Additionally, R waves were compared at implant and at 1-month follow-up.</AbstractText>A total of 50 patients were enrolled into the study. When evaluating the primary endpoint, no difference was found between USB in EBP or TBP configuration; 1.1 ± 1.2 beats versus 1.3 ± 1.3 beats; P = NS. Also, no difference was found between TDVF in EBP or TBP configurations; 5.9 ± 0.6 seconds versus 5.9 ± 0.6 seconds; P = NS. With regard to the secondary endpoints, there was no difference between R waves in EBP or TBP configurations at the time of implant 10.9 ± 4.8 mV versus 10.9 ± 4.8 mV P = NS; or at 1-month follow-up 12.4 ± 4.7 mV versus 12.0 ± 5.4 mV P = NS.</AbstractText>There is no difference in the detection of VF between EBP or TBP configurations in patients undergoing ICD implantation.</AbstractText>©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.</CopyrightInformation> |
13,288 | ECG of the month. Cardiac failure and stroke in a 43-year-old woman. Coarse atrial fibrillation indicating left atrial enlargement and left ventricular hypertrophy with repolarization abnormality. | A 43-year-old woman with a long history of heavy cigarette smoking was in good health until she developed fatigue, dyspnea on exertion, and paroxysmal nocturnal dyspnea approximately three months before admission to our hospital. Four weeks before admission, she was admitted to another hospital for the sudden onset of a right hemiparesis. She was noted to be in atrial fibrillation, and cardiac catheterization and angiocardiography revealed triple-vessel coronary arterial disease and moderately severe mitral regurgitation. Because of repeated episodes of paroxysmal nocturnal dyspnea, she was referred to our hospital for cardiac surgery. On admission, an electrocardiogram was recorded (Figure). |
13,289 | SNPs identified as modulators of ECG traits in the general population do not markedly affect ECG traits during acute myocardial infarction nor ventricular fibrillation risk in this condition. | Ventricular fibrillation (VF) in the setting of acute ST elevation myocardial infarction (STEMI) is a leading cause of mortality. Although the risk of VF has a genetic component, the underlying genetic factors are largely unknown. Since heart rate and ECG intervals of conduction and repolarization during acute STEMI differ between patients who do and patients who do not develop VF, we investigated whether SNPs known to modulate these ECG indices in the general population also impact on the respective ECG indices during STEMI and on the risk of VF.</AbstractText>The study population consisted of participants of the Arrhythmia Genetics in the NEtherlandS (AGNES) study, which enrols patients with a first STEMI that develop VF (cases) and patients that do not develop VF (controls). SNPs known to impact on RR interval, PR interval, QRS duration or QTc interval in the general population were tested for effects on the respective STEMI ECG indices (stage 1). Only those showing a (suggestive) significant association were tested for association with VF (stage 2). On average, VF cases had a shorter RR and a longer QTc interval compared to non-VF controls. Eight SNPs showed a trend for association with the respective STEMI ECG indices. Of these, three were also suggestively associated with VF.</AbstractText>RR interval and ECG indices of conduction and repolarization during acute STEMI differ between patients who develop VF and patients who do not. Although the effects of the SNPs on ECG indices during an acute STEMI seem to be similar in magnitude and direction as those found in the general population, the effects, at least in isolation, are too small to explain the differences in ECGs between cases and controls and to determine risk of VF.</AbstractText> |
13,290 | mRNA expression levels in failing human hearts predict cellular electrophysiological remodeling: a population-based simulation study. | Differences in mRNA expression levels have been observed in failing versus non-failing human hearts for several membrane channel proteins and accessory subunits. These differences may play a causal role in electrophysiological changes observed in human heart failure and atrial fibrillation, such as action potential (AP) prolongation, increased AP triangulation, decreased intracellular calcium transient (CaT) magnitude and decreased CaT triangulation. Our goal is to investigate whether the information contained in mRNA measurements can be used to predict cardiac electrophysiological remodeling in heart failure using computational modeling. Using mRNA data recently obtained from failing and non-failing human hearts, we construct failing and non-failing cell populations incorporating natural variability and up/down regulation of channel conductivities. Six biomarkers are calculated for each cell in each population, at cycle lengths between 1500 ms and 300 ms. Regression analysis is performed to determine which ion channels drive biomarker variability in failing versus non-failing cardiomyocytes. Our models suggest that reported mRNA expression changes are consistent with AP prolongation, increased AP triangulation, increased CaT duration, decreased CaT triangulation and amplitude, and increased delay between AP and CaT upstrokes in the failing population. Regression analysis reveals that changes in AP biomarkers are driven primarily by reduction in I[Formula: see text], and changes in CaT biomarkers are driven predominantly by reduction in I(Kr) and SERCA. In particular, the role of I(CaL) is pacing rate dependent. Additionally, alternans developed at fast pacing rates for both failing and non-failing cardiomyocytes, but the underlying mechanisms are different in control and heart failure. |
13,291 | Atrial fibrillation and sinus node dysfunction in human ankyrin-B syndrome: a computational analysis. | Ankyrin-B is a multifunctional adapter protein responsible for localization and stabilization of select ion channels, transporters, and signaling molecules in excitable cells including cardiomyocytes. Ankyrin-B dysfunction has been linked with highly penetrant sinoatrial node (SAN) dysfunction and increased susceptibility to atrial fibrillation. While previous studies have identified a role for abnormal ion homeostasis in ventricular arrhythmias, the molecular mechanisms responsible for atrial arrhythmias and SAN dysfunction in human patients with ankyrin-B syndrome are unclear. Here, we develop a computational model of ankyrin-B dysfunction in atrial and SAN cells and tissue to determine the mechanism for increased susceptibility to atrial fibrillation and SAN dysfunction in human patients with ankyrin-B syndrome. Our simulations predict that defective membrane targeting of the voltage-gated L-type Ca(2+) channel Cav1.3 leads to action potential shortening that reduces the critical atrial tissue mass needed to sustain reentrant activation. In parallel, increased fibrosis results in conduction slowing that further increases the susceptibility to sustained reentry in the setting of ankyrin-B dysfunction. In SAN cells, loss of Cav1.3 slows spontaneous pacemaking activity, whereas defects in Na(+)/Ca(2+) exchanger and Na(+)/K(+) ATPase increase variability in SAN cell firing. Finally, simulations of the intact SAN reveal a shift in primary pacemaker site, SAN exit block, and even SAN failure in ankyrin-B-deficient tissue. These studies identify the mechanism for increased susceptibility to atrial fibrillation and SAN dysfunction in human disease. Importantly, ankyrin-B dysfunction involves changes at both the cell and tissue levels that favor the common manifestation of atrial arrhythmias and SAN dysfunction. |
13,292 | Defibrillation success is not associated with near field electrogram complexity or shock timing. | It has been suggested that more-complex fibrillation requires higher energy shocks to terminate. Furthermore, animal studies have demonstrated that shock timing also plays a role. The objective of this study was to test these assertions in a clinical context.</AbstractText>Near- and far-field electrograms were collected during defibrillation threshold testing. Fibrillation complexity was measured by quantifying the organization in the signals with wavelet-based methods, scaling exponent, and cross-correlation analysis. Receiver operator characteristic curves were used to determine predictive value. The effect of the phase at which defibrillation shocks were applied was also determined.</AbstractText>No measure was able to classify whether a particular shock would be successful. All performed very poorly. Shock timing played no role in defibrillation outcome.</AbstractText>Signal organization of a local electrogram and phase of shock delivery do not relate to minimum defibrillation shock energy immediately after ventricular fibrillation onset.</AbstractText>Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
13,293 | Long-term complications of implantable defibrillator therapy in Brugada syndrome. | Although the benefits of implantable cardioverter-defibrillator (ICD) therapy in patients with Brugada syndrome (BrS) at risk of sudden cardiac arrest are well established, these relatively young patients can encounter complications in the long term. The objective of the present study was to determine the incidence of device complications in patients with BrS during long-term follow-up. The prevalence of device-related complications and the clinical outcome were determined in 41 consecutive patients with BrS (age 48 ± 12 years; 38 men) who were treated with ICD implantation. During a median follow-up of 76 months (interquartile range 51 to 98), 15 patients (37%) experienced 21 adverse events, including 11 device-related complications in 8 (20%) and ≥1 inappropriate shock in 10 (24%). Five patients (12%) received appropriate shocks for ventricular fibrillation. Excluding inappropriate shocks, 95.1%, 89.6%, 86.6%, and 73.3% of patients were free of device-related complications at 1, 3, 5, and 7 years, respectively. Also, 92.6%, 89.8%, 89.9%, and 86.1% were free of lethal arrhythmias at 1, 3, 5, and 7 years, respectively. Adverse effects related to ICD implantation are not uncommon, and their prevalence increases with the follow-up duration required for patients with BrS. In conclusion, because complications can be encountered even very late after device implantation, asymptomatic young patients should be carefully selected and educated about the long-term outcomes of ICD therapy. |
13,294 | Relation of red cell distribution width with CHA2DS2-VASc score in patients with nonvalvular atrial fibrillation. | Red cell distribution width (RDW) has been shown to be helpful in predicting adverse long-term events in patients with cardiovascular diseases. However, to date, no study has been conducted on the relationship between RDW and thromboembolism risk in atrial fibrillation (AF). Therefore, we aimed to investigate the relationship between RDW and CHA2DS2-VASc score used for the evaluation of thromboembolism risk in patients with AF.</AbstractText>The study population consisted of 320 patients with AF. We calculated CHA2DS2-VASc risk score for each patient and baseline hemoglobin, white blood cell, RDW, mean platelet volume, platelet counts, estimated glomerular filtration rate (eGFR), left ventricular ejection fraction (LVEF), and left atrial volume index (LAVi) were measured.</AbstractText>High CHA2DS2-VASc score group had higher RDW, lower LVEF, higher LAVi, and lower eGFR values when compared to the low CHA2DS2-VASc score group. The multivariate logistic regression analysis performed to predict high CHA2DS2-VASc scores revealed that RDW eGFR, LVEF, and LAVi were independent predictors. The area under the receiver-operating characteristic curve of RDW was 0.65 (0.59-0.71, P < .001) to predict high CHA2DS2-VASc score.</AbstractText>Our study results indicate that RDW values are significantly correlated with CHA2DS2-VASc score in nonanemic patients with AF, while also being independent predictor of high CHA2DS2-VASc score.</AbstractText>© The Author(s) 2013.</CopyrightInformation> |
13,295 | Omega-3 in antiarrhythmic therapy : cons position. | The association between omega-3 (n-3 polyunsaturated fatty acids) and the clinical outcome of patients with cardiovascular diseases such as coronary heart disease is currently unclear, especially regarding its possible antiarrhythmic effects and the not quite understood mechanisms of action. In the last 15 years, several epidemiological studies have shown a lower incidence of sudden cardiac death with a diet rich in omega-3 or fish consumption. The antiarrhythmic properties related to omega-3 have been related to modulation of sodium-dependent ion channels or sodium-calcium exchangers of myocytes through a reduction of their excitability especially in ischaemic or damaged myocardial tissue. However, the results of experimental studies have not always been consistent. Although the role of omega-3 in preventing sudden cardiac death has been evaluated in several clinical trials that included patients with coronary artery disease (particularly in patients with post-myocardial infarction), the interpretation of such data must be treated with extreme caution. In particular, while a reduction in cardiac death was demonstrated by a meta-analysis of several randomized clinical trials, a reduced risk of sudden cardiac death has been described only in the GISSI-Prevenzione study, while in other studies the evidence that emerged is more controversial, with wide confidence intervals that support the possibility of heterogeneity in the distribution of the factors involved in the efficacy of treatment. Omega-3 is probably involved in the prevention of cardiovascular mortality through different mechanisms, and it is crucial to study its association with other drugs such as ACE inhibitors or calcium channel blockers. The study of antiarrhythmic drugs has been divided into prevention of supraventricular and ventricular arrhythmias. In these conditions, the role of omega-3 seems to be more pronounced in atrial tachyarrhythmias such as atrial fibrillation, but does not have a role in ventricular arrhythmias. In summary, the antiarrhythmic effect of omega-3 is not clearly evident and further studies are needed to investigate its beneficial effect in cardiac mortality compared with arrhythmic death. |
13,296 | Electrical storm: recent pathophysiological insights and therapeutic consequences. | The implantable cardioverter-defibrillator significantly improves survival in patients with malignant ventricular arrhythmias but does not target the underlying pathological substrate responsible for arrhythmic events. A significant proportion of defibrillator recipients experience multiple ventricular tachycardia/fibrillation episodes over a short period of time, termed electrical storm (ES). The current therapeutic strategy for ES is complex and unsatisfactory because simultaneous administration of several medications and additional invasive procedures are often required to control ES. Moreover, this treatment does not favorably influence the long-term outcome. Clearly, improved ES therapies are necessary and desirable, but a lack of understanding of the pathophysiological mechanisms underlying ES has hindered the development of more effective, rationally based therapeutic approaches. This paper reviews emerging experimental and clinical findings that provide insights into the pathophysiology of ES and discusses mechanism-based innovative therapeutic strategies. |
13,297 | Low-dose bisphenol A and estrogen increase ventricular arrhythmias following ischemia-reperfusion in female rat hearts. | Bisphenol A (BPA) is an environmental estrogenic endocrine disruptor that may have adverse health impacts on a range of tissue/systems. In previous studies, we reported that BPA rapidly promoted arrhythmias in female rodent hearts through alteration of myocyte calcium handling. In the present study we investigated the acute effects of BPA on ventricular arrhythmias and infarction following ischemia-reperfusion in rat hearts. Rat hearts were subjected to 20 min of global ischemia followed by reperfusion. In female, but not male hearts, acute exposure to 1 nM BPA, either alone or combined with 1 nM 17β-estradiol (E2), during reperfusion resulted in a marked increase in the duration of sustained ventricular arrhythmias. BPA plus E2 increased the duration ventricular fibrillation, and the duration of VF as a fraction of total duration of sustained ventricular arrhythmia. The pro-arrhythmic effects of estrogens were abolished by MPP combined with PHTPP, suggesting the involvements of both ERα and ERβ signaling. In contrast to their pro-arrhythmic effects, BPA and E2 reduced infarction size, agreeing with previously described protective effect of estrogen against cardiac infarction. In conclusion, rapid exposure to low dose BPA, particularly when combined with E2, exacerbates ventricular arrhythmia following IR injury in female rat hearts. |
13,298 | Hypertension accelerates the 'normal' aging process with a premature increase in left atrial volume. | Hypertension (HT) is associated with left ventricular (LV) diastolic dysfunction and consequent left atrial (LA) dilatation. We investigated changes in LA size and phasic function by decade in patients with HT. Patients with mild or moderate HT (n = 122) were compared with a case controlled normal cohort (blood pressure <140/90 mm Hg). Biplane LA maximum, minimum, and pre 'a' wave volumes were measured; LA filling, passive emptying, and active emptying volumes and fractions were calculated. Transmitral inflow and pulsed wave mitral annular tissue Doppler velocity were measured as expressions of LV diastolic function. The HT group had larger LA maximum volumes compared with normal controls for all decades until the 8th decade. Subjects with HT in decade 4 had LA maximum volume similar to that of normal controls from decade 8 (27.8 ± 4.3 mL/m(2) vs 25.6 ± 6.1 mL/m(2) respectively, P = .22). Active emptying volume and fraction were higher in the HT group across all decades, while there was no difference between the HT and normal groups for passive emptying volume. LV mass and E/E' ratio were significantly higher across all decades in the HT group. HT alters atrial dynamics significantly, with resultant increased LA volume and active emptying volume consequent to altered LV diastolic function. HT 'accelerates' the normal aging process with patients as early as decade 4 having similar LA size to that of normal controls in decade 8. This premature increase in LA volume may result in the future development of atrial fibrillation in HT patients. |
13,299 | The impact of telemetry on survival of in-hospital cardiac arrests in non-critical care patients. | Since the introduction of telemetry over a half century ago, it has expanded to various units and wards within health care institutions outside of the traditional critical care setting. Little is known on whether routine telemetry use is beneficial in this patient population. The aim of this study was to determine the impact of telemetry monitoring on survival of in-hospital cardiac arrests in patients admitted to non-critical care units.</AbstractText>A retrospective study of cardiac arrests in patients admitted to non-critical care units within the Winnipeg Regional Health Authority from 2002 to 2006 inclusive was performed. Baseline demographic, cardiac arrest, and outcome data were collected.</AbstractText>Of the total 668 patients, the mean age was 70±14 years with 404 (61%) males. Patients presenting with asystole or pulseless electrical activity (PEA) demonstrated an increased mortality as compared to those presenting with ventricular tachycardia (VT) or ventricular fibrillation (VF). Overall, 268 of 668 patients (40%) survived their initial arrest, 66 (10%) survived to hospital discharge and 49 (7%) survived transfer to another facility. Patients on telemetry vs. no telemetry had higher survival rates immediately following cardiac arrest (66% vs. 34%, OR=3.67, p=0.02), as well as higher survival to hospital discharge (30% vs. 6%, OR=7.17, p=0.01). Finally, patients with cardiac arrest during the night and early morning benefited proportionally the greatest from telemetry use.</AbstractText>Regardless of whether cardiac arrest was witnessed or unwitnessed, telemetry use was an independent and strong predictor of survival to hospital discharge.</AbstractText>Copyright © 2013. Published by Elsevier Ireland Ltd.</CopyrightInformation> |
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