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7,200 | Echocardiographic and clinical risk factors for atrial fibrillation in hypertensive patients with ischemic stroke. | Atrial fibrillation (AF) is a common cause of ischemic stroke. Because anticoagulation can prevent many of these strokes, identifying patients with occult intermittent AF is important. Hypertension is a common precursor of stroke and AF. Prolonged nonselective electrocardiographic monitoring of patients after ischemic stroke has yielded only a small number of patients with occult intermittent AF. To determine the importance of AF in nonhemorrhagic stroke, we retrospectively studied 799 patients admitted with ischemic stroke over 31 months. AF was present on the admitting electrocardiogram in 154 patients (19.3%), diagnosed later during the stroke admission in 58 (7.3%), and found only during another admission before/after the stroke admission in 46 (5.8%). AF was intermittent in 123 patients, 47.7% (95% CI 41.6 to 53.8) of patients with AF, and not present on initial electrocardiogram in 40.3% of patients with AF. In 633 patients with hypertension, AF occurred in 34.9% versus 22.2% without hypertension (p <0.01). Echocardiogram revealed a left atrium > or =4.0 cm in 81.3% of patients with AF versus 42.4% of those without AF (odds ratio [OR] 5.85, 95% confidence interval [CI] 3.87 to 8.96, p <0.001); ejection fraction was <50% in 27.7% of patients with AF versus 12.6% of those without AF (OR 2.63, 95% CI 1.65 to 4.22, p <0.001); and the left ventricle was > or =5.6 cm in 13.8% in patients with AF versus 6.7% in those without AF (OR 2.21, 95% CI 1.61 to 3.04, p <0.01). Clinically, congestive heart failure (31% vs 10.4%, OR 3.89, 95% CI 2.76 to 5.73) and coronary disease (31% vs 21.4%, OR 1.65, 95% CI 1.15 to 2.37) were present more often in patients with AF (p <0.001). Left ventricular hypertrophy, diastolic dysfunction, and diabetes were common in all hypertensive patients with stroke. In conclusion, hypertensive patients with these risk factors should undergo prolonged electrocardiographic event monitoring to identify occult intermittent AF so measures can be taken to prevent a second stroke and possibly a first stroke. |
7,201 | Analysis of prehospital care for cardiac arrest in an urban setting in Japan. | In Japan, the management of prehospital care for cardiopulmonary arrest (CPA) has recently changed.</AbstractText>The characteristics of prehospital care for CPA were analyzed to identify predictors of prehospital return of spontaneous circulation (PROSC) and good recovery.</AbstractText>The characteristics of prehospital management of 713 out-of-hospital CPA patients in the First Western District of Saitama Prefecture, Japan, were retrospectively analyzed.</AbstractText>Overall, PROSC rate was 9.5% (n = 68), and 2.2% of patients (n = 16) made a good recovery. Significant positive predictors of PROSC were: duration from the first call to hospital arrival, witnessed collapse, ventricular fibrillation at scene, and epinephrine administration. Establishment of supraglottic airway was a significant negative predictor of PROSC. Significant positive predictors of good recovery were younger age, ventricular fibrillation at scene, and PROSC. Changes to the life support protocol based on 2005 guidelines did not affect the outcome.</AbstractText>Epinephrine was effective in increasing PROSC; however, it did not improve recovery of such patients. The findings also suggest that out-of-hospital care providers should not try to establish a supraglottic airway.</AbstractText>Copyright 2010 Elsevier Inc. All rights reserved.</CopyrightInformation> |
7,202 | Reduced hands-off-time and time to first shock in CPR according to the ERC Guidelines 2005. | Chest compressions and early defibrillation are crucial in cardiopulmonary resuscitation (CPR). The Guidelines 2005 brought major changes to the basic life support and automated external defibrillator (BLS-AED) algorithm. We compared the European Resuscitation Council's Guidelines 2000 (group '00) and 2005 (group '05) on hands-off-time (HOT) and time to first shock (TTFS) in an experimental model.</AbstractText>In a randomised, cross-over design, volunteers were assessed in performing BLS-AED over a period of 5min on a manikin in a simulated ventricular fibrillation cardiac arrest situation. Ten minutes of standardised teaching and 10min of training including corrective feedback were allocated for each of the guidelines before evaluation. HOT was chosen as the primary and TTFS as the secondary outcome parameter.</AbstractText>Forty participants were enrolled; one participant dropped out after group allocation. During the 5-min evaluation period of adult BLS-AED, HOT was significantly (p<0.001) longer in group '00 [273+/-3s (mean+/-standard error)] than in group '05 (188+/-3s). The TTFS was significantly (p<0.001) longer in group '00 (91+/-3s) than in group '05 (71+/-3s).</AbstractText>In this manikin setting, HOT and TTFS improved with BLS-AED performed according to Guidelines 2005.</AbstractText> |
7,203 | T-wave alternans found in preventricular tachyarrhythmias in CCU patients using a wavelet transform-based methodology. | Ventricular tachyarrhythmias are potentially lethal cardiac pathologies and the commonest cause of sudden cardiac death. Efforts to predict the onset of such events are based on feature extraction from the surface ECG. T-wave alternans (TWAs) are considered a marker of abnormal ventricular function that may be associated with ventricular tachycardia (VT) and ventricular fibrillation. A novel TWA detection algorithm utilizing the continuous wavelet transform is described in this paper. Simulated ECGs containing artificial TWA were used to test the algorithm that achieved a sensitivity of 91.40% and a specificity of 94.00%. The algorithm was subsequently used to analyze the ECGs of eight patients prior to the onset of VT. Of these, the algorithm indicated that five patients exhibited TWA prior to the onset of the tachyarrhythmic events, while the remaining three patients did not exhibit identifiable TWA. Healthy individuals were also studied in which one short TWA episode was detected by the algorithm. However, closer visual inspection of the data revealed this to be a likely false positive result. |
7,204 | Phase-rectified signal averaging used to estimate the dominant frequencies in ECG signals during atrial fibrillation. | Phase-rectified signal averaging (PRSA) is a technique recently introduced to enhance quasi-periodic signal components. An important parameter that can be extracted from surface ECG is the dominant frequency (DF) of atrial fibrillation (AF). AF signal components are always highly contaminated by the ventricular complexes, and the cancellation of these components is never perfect. The remaining artifacts tend to induce erroneous DF estimates. In this paper, we report on the use of PRSA in the context of noninvasive AF classification procedures for improving DF estimation. The potential of PRSA is demonstrated by experiments both on synthetic and clinical ECG signals. |
7,205 | The whole nine yards: multiple cardiac surgical and percutaneous interventions in a patient during 30 years of care. | A 38-year-old man underwent coronary artery bypass graft surgery for angina pectoris following myocardial infarction. During the following 28 years, he required two repeat coronary artery bypass graft surgical procedures, nine percutaneous coronary interventions and 17 coronary angiograms. His treatment included saphenous vein, left internal mammary artery and gastroepiploic artery grafting, percutaneous transluminal coronary angioplasty and intragraft thrombolytic therapy, directional coronary atherectomy, cutting balloon angioplasty, intracoronary stenting with bare-metal and drug-eluting stents, treatment for in-stent restenosis, stenting of the left main and circumflex coronary arteries and saphenous vein graft as well as intracoronary pressure wire diagnostics. In addition to his statin therapy, antiplatelets and angiotensin-converting enzyme inhibitors, he also underwent biventricular automatic implantable cardioverter-defibrillator implantation and atrioventricular node radiofrequency ablation for his impaired left ventricular function, ventricular tachycardia and rapid atrial fibrillation. The present unusual case represents almost 'the whole nine yards' of treatment that has become available to patients with coronary artery disease during the past 30 years of technological development.</Abstract><AuthorList CompleteYN="Y"><Author ValidYN="Y"><LastName>Albouaini</LastName><ForeName>Khaled</ForeName><Initials>K</Initials><AffiliationInfo><Affiliation>The Cardiothoracic Centre, Liverpool, Merseyside, United Kingdom.</Affiliation></AffiliationInfo></Author><Author ValidYN="Y"><LastName>Ramsdale</LastName><ForeName>Kathryn A</ForeName><Initials>KA</Initials></Author><Author ValidYN="Y"><LastName>Ramsdale</LastName><ForeName>David R</ForeName><Initials>DR</Initials></Author></AuthorList><Language>eng</Language><PublicationTypeList><PublicationType UI="D002363">Case Reports</PublicationType><PublicationType UI="D016428">Journal Article</PublicationType></PublicationTypeList></Article><MedlineJournalInfo><Country>England</Country><MedlineTA>Can J Cardiol</MedlineTA><NlmUniqueID>8510280</NlmUniqueID><ISSNLinking>0828-282X</ISSNLinking></MedlineJournalInfo><CitationSubset>IM</CitationSubset><MeshHeadingList><MeshHeading><DescriptorName UI="D000328" MajorTopicYN="N">Adult</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D000787" MajorTopicYN="N">Angina Pectoris</DescriptorName><QualifierName UI="Q000175" MajorTopicYN="N">diagnosis</QualifierName><QualifierName UI="Q000628" MajorTopicYN="N">therapy</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D015906" MajorTopicYN="N">Angioplasty, Balloon, Coronary</DescriptorName><QualifierName UI="Q000379" MajorTopicYN="N">methods</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D001281" MajorTopicYN="N">Atrial Fibrillation</DescriptorName><QualifierName UI="Q000000981" MajorTopicYN="N">diagnostic imaging</QualifierName><QualifierName UI="Q000601" MajorTopicYN="Y">surgery</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D017115" MajorTopicYN="N">Catheter Ablation</DescriptorName><QualifierName UI="Q000379" MajorTopicYN="N">methods</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D002404" MajorTopicYN="N">Catheterization</DescriptorName><QualifierName UI="Q000379" MajorTopicYN="N">methods</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D003131" MajorTopicYN="N">Combined Modality Therapy</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D017023" MajorTopicYN="N">Coronary Angiography</DescriptorName><QualifierName UI="Q000379" MajorTopicYN="N">methods</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D001026" MajorTopicYN="N">Coronary Artery Bypass</DescriptorName><QualifierName UI="Q000379" MajorTopicYN="Y">methods</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D023903" MajorTopicYN="N">Coronary Restenosis</DescriptorName><QualifierName UI="Q000628" MajorTopicYN="Y">therapy</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D017147" MajorTopicYN="N">Defibrillators, Implantable</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D054855" MajorTopicYN="N">Drug-Eluting Stents</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D005500" MajorTopicYN="N">Follow-Up Studies</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D006801" MajorTopicYN="N">Humans</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D008297" MajorTopicYN="N">Male</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D009203" MajorTopicYN="N">Myocardial Infarction</DescriptorName><QualifierName UI="Q000175" MajorTopicYN="Y">diagnosis</QualifierName><QualifierName UI="Q000628" MajorTopicYN="Y">therapy</QualifierName></MeshHeading><MeshHeading><DescriptorName UI="D010138" MajorTopicYN="N">Pacemaker, Artificial</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D012086" MajorTopicYN="N">Reoperation</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D018570" MajorTopicYN="N">Risk Assessment</DescriptorName></MeshHeading><MeshHeading><DescriptorName UI="D013997" MajorTopicYN="N">Time Factors</DescriptorName></MeshHeading></MeshHeadingList><OtherAbstract Type="Publisher" Language="fre">Un homme de 38 ans a subi un pontage aortocoronarien en raison d’une angine de poitrine suivant un infarctus du myocarde. Pendant les 28 années qui ont suivi, il a subi deux nouveaux pontages aortocoronariens, neuf interventions coronaires percutanées et 17 coronarographies. Il a subi des greffes à la veine saphène, à l’artère thoracique interne gauche et à l’artère gastroépiploïque, une angioplastie coronaire transluminale percutanée et une thérapie thrombolytique intragreffe, une athérectomie coronaire directionnelle, une angioplastie par ballonnet, l’installation d’une endoprothèse intracoronaire à métal nu et d’endoprothèses à élution de médicament, un traitement de nouvelle sténose dans l’endoprothèse, l’installation d’une endoprothèse de l’artère coronaire gauche principale, de l’artère circonflexe et de la greffe de la veine saphène ainsi que des diagnostics de pression sur les fils intracoronaire. Outre une thérapie aux statines, aux antiplaquettaires et aux inhibiteurs de l’enzyme de conversion de l’angiotensine, le patient a également reçu un défibrillateur à synchronisation automatique biventriculaire, subi l’ablation de la radiofréquence du nœud auriculoventriculaire en raison de la défaillance de la fonction ventriculaire gauche, une tachycardie ventriculaire et une fibrillation auriculaire rapide. Ce cas inhabituel représente presque toute la panoplie des traitements offerts aux patients atteints d’une coronaropathie en 30 ans de progrès technologiques. |
7,206 | Distinct lethal arrhythmias susceptibility is associated with sex-related difference in myocardial connexin-43 expression. | To elucidate gender-related differences in occurrence of sudden cardiac death the myocardial connexin-43 (Cx43) and the susceptibility of male and female rat hearts to ventricular fibrillation (VF) were investigated.</AbstractText>Ventricular tissues taken from male and female normotensive Wistar and spontaneously hypertensive (SHR) rats were processed for immuno-fluorescence and immuno-blotting of Cx43. Susceptibility to ventricular fibrillation was examined in isolated heart preparation using either electrical stimulation or low K+ perfusion. Results showed that VF susceptibility of male either normotensive or hypertensive rats was significantly increased comparing to female counterparts. In correlation, ventricular expression of Cx43 was markedly lower in males of both normotensive and hypertensive rats comparing to females. SHR in addition exhibited abnormal myocardial Cx43 distribution due to structural remodelling.</AbstractText>Findings indicate that higher level of myocardial Cx43 expression is linked with lower lethal arrhythmia susceptibility and vice versa. It appears that Cx43 can be involved in sex-related differences in incidence of life-threatening arrhythmias.</AbstractText> |
7,207 | Acute beta-adrenoceptor blockade improves efficacy of ibutilide in conversion of atrial fibrillation with a rapid ventricular rate. | Activation of beta-adrenoceptors attenuates prolongation of action potential duration induced by blockade of the delayed rectifier potassium current. We examined whether acute administration of beta-blocker could enhance ibutilide (IB) efficacy in conversion of atrial fibrillation (AF) with a rapid ventricular rate.</AbstractText>Ninety patients (aged 63 +/- 13.5 years) with rapidly conducting AF were randomized in to two groups. Group A (n = 44) received esmolol titrated to achieve a heart rate of <100 bpm followed by IB co-administration, while Group B (n = 46) were treated with IB as monotherapy. In Group A, 29 patients (67%) converted to sinus rhythm (SR) compared with 21 (46%) in Group B (P = 0.04). The use of esmolol was the most important predictor for cardioversion (P = 0.009). The slower the heart rate at the time of IB initiation, the higher the likelihood for cardioversion (P = 0.015). Patients in Group A had significantly shorter corrected QT interval (QTc) at the time of conversion than those in Group B (433 vs. 501 ms, P = 0.003). Two patients in Group A developed severe bradycardia, whereas three patients in Group B developed severe ventricular tachycardia (VT).</AbstractText>Compared with IB monotherapy, the combination therapy of esmolol and IB appears to be more effective in conversion of rapidly conducting AF back to SR. The addition of beta-blocker reduces QTc prolongation and diminishes the risk of VT at the expense, however, of increased bradycardic events.</AbstractText> |
7,208 | Defibrillation or cardiopulmonary resuscitation first for patients with out-of-hospital cardiac arrests found by paramedics to be in ventricular fibrillation? A randomised control trial. | To determine whether in patients with an ambulance response time of >5min who were in VF cardiac arrest, 3min of CPR before the first defibrillation was more effective than immediate defibrillation in improving survival to hospital discharge.</AbstractText>This randomised control trial was run by the South Australian Ambulance Service between 1 July, 2005, and 31 July, 2007. Patients in VF arrest were eligible for randomisation. Exclusion criteria were: (i) <18 years of age, (ii) traumatic arrest, (iii) paramedic witnessed arrest, (iv) advanced life support performed before arrival of paramedics and (v) not for resuscitation order or similar directive. The primary outcome was survival to hospital discharge with secondary outcomes being neurological status at discharge, the rate of return of spontaneous circulation (ROSC) and the time from first defibrillation to ROSC.</AbstractText>For all response times, no differences were observed between the immediate defibrillation group and the CPR first group in survival to hospital discharge (17.1% [18/105] vs. 10.3% [10/97]; P=0.16), the rate of ROSC (53.3% [56/105] vs. 50.5% [49/97]; P=0.69) or the time from the first defibrillation to ROSC (12:37 vs. 11:19; P=0.49). There were also no differences between the immediate defibrillation group and the CPR first group, for response times of < or = or > 5min: survival to hospital discharge (50.0% [7/14] vs. 25.0% [4/16]; P=0.16 or 12.1% [11/91] vs.7.4% [6/81]; P=0.31, respectively) and the rate of ROSC (71.4% [10/14] vs. 75.0% [12/16]; P=0.83 or 50.5% [46/91] vs. 45.7% [37/81]; P=0.54, respectively). No differences were observed in the neurological status of those surviving to hospital discharge.</AbstractText>For patient in out-of-hospital VF cardiac arrest we found no evidence to support the use of 3min of CPR before the first defibrillation over the accepted practice of immediate defibrillation.</AbstractText> |
7,209 | Echo determinants of dyssynchrony (atrioventricular and inter- and intraventricular) and predictors of response to cardiac resynchronization therapy. | Cardiac resynchronization therapy (CRT) has revolutionized not only the treatment of chronic heart failure but also how we assess left ventricular (LV) dysfunction on echo. Increasingly, it has become clear that identifying and quantifying delays in events during the cardiac cycle is an important assessment in LV dysfunction as it has prognostic implications for patients undergoing CRT. The delays in atrioventricular, right-to-left ventricular, and LV segmental contraction have been shown to be important components in cardiac performance, and this review provides an overview of the commonest methods used for these assessments and their implications for selecting patients for biventricular pacing. |
7,210 | Intracardiac echocardiography in electrophysiology: a review of current applications in practice. | Intracardiac echocardiography (ICE) has emerged as a widespread useful tool in the everyday practice of interventional electrophysiology. Advances in catheter-based ultrasound transducers and imaging technology have made this modality integral to guiding evaluation of anatomy and ablation therapy. Evolution of ablative procedures of the left heart for tachyarrhythmia has highlighted the importance of direct visualization of anatomic landmarks to guide transseptal catheterization and immediately identify complications. The ability to position mapping and ablation catheters according to anatomic landmarks (Fig. 1) has greatly enhanced the safety and efficacy of catheter ablation procedures. ICE has supplanted fluoroscopy as the gold standard for precise imaging of endocardial structures during complex procedures. |
7,211 | Mitral regurgitation and cardiac resynchronization therapy. | Secondary mitral regurgitation (MR) is frequent in patients with severely depressed left ventricular function. It increases mortality, and decreases exercise capacity. Its main mechanisms are multifactorial, related to apical and outward displacement of the papillary muscles, secondary to an enlarged and a more spherical left ventricle, causing increased subvalvar traction; mitral annular dilatation; and poor contraction of the left ventricle, with a slowed rate of rise of intraventricular pressure and slow closure of the leaflets. Since mechanical dyssynchrony is a major contributor factor to secondary MR, cardiac resynchronization therapy (CRT) could be considered as an alternative therapeutic option for MR, alone or in combination with surgical correction. Effects of CRT on secondary MR are acute and long-term, due to the reverse remodeling of the left ventricle. CRT reduces systolic MR by 30-40%, both at rest and during exercise, and abolishes diastolic MR, by increase of the closing forces and decrease of the tethering forces, acting on the mitral valve; decrease of the mitral annular dilatation represents a minor mechanism. Patients more likely to benefit should have moderate-to-severe MR (but not too severe), of nonischemic etiology, and high interpapillary muscles dyssynchrony. Effects are similar in patients with sinus rhythm and in patients with atrial fibrillation, and in patients with broad and narrow QRS complexes, provided that they have similar extent of dyssynchrony. Biventricular mode is the pacing modality of choice. |
7,212 | Transmural recording of shock potential gradient fields, early postshock activations, and refibrillation episodes associated with external defibrillation of long-duration ventricular fibrillation in swine. | Knowledge of the shock potential gradient (nablaV) and postshock activation is limited to internal defibrillation of short-duration ventricular fibrillation (SDVF).</AbstractText>The purpose of this study was to determine these variables after external defibrillation of long-duration VF (LDVF).</AbstractText>In six pigs, 115-20 plunge needles with three to six electrodes each were inserted to record throughout both ventricles. After the chest was closed, the biphasic defibrillation threshold (DFT) was determined after 20 seconds of SDVF with external defibrillation pads. After 7 minutes of LDVF, defibrillation shocks that were less than or equal to the SDVF DFT strength were given.</AbstractText>For DFT shocks (1632 +/- 429 V), the maximum minus minimum ventricular voltage (160 +/- 100 V) was 9.8% of the shock voltage. Maximum cardiac nablaV (28.7 +/- 17 V/cm) was 4.7 +/- 2.0 times the minimum nablaV (6.2 +/- 3.5 V/cm). Although LDVF did not increase the DFT in five of the six pigs, it significantly lengthened the time to earliest postshock activation following defibrillation (1.6 +/- 2.2 seconds for SDVF and 4.9 +/- 4.3 seconds for LDVF). After LDVF, 1.3 +/- 0.8 episodes of spontaneous refibrillation occurred per animal, but there was no refibrillation after SDVF.</AbstractText>Compared with previous studies of internal defibrillation, during external defibrillation much less of the shock voltage appears across the heart and the shock field is much more even; however, the minimum nablaV is similar. Compared with external defibrillation of SDVF, the biphasic external DFT for LDVF is not increased; however, time to earliest postshock activation triples. Refibrillation is common after LDVF but not after SDVF in these normal hearts, indicating that LDVF by itself can cause refibrillation without requiring preexisting heart disease.</AbstractText> |
7,213 | Electrophysiological mechanisms of antiarrhythmic protection during hypothermia in winter hibernating versus nonhibernating mammals. | Robust cell-to-cell coupling is critically important in the safety of cardiac conduction and protection against ventricular fibrillation (VF). Hibernating mammals have evolved naturally protective mechanisms against VF induced by hypothermia and reperfusion injury.</AbstractText>We hypothesized that this protection strategy involves a dynamic maintenance of conduction and repolarization patterns through the improvement of gap junction functions.</AbstractText>We optically mapped the hearts of summer-active (SA) and winter-hibernating (WH) ground squirrels Spermophilus undulatus from Siberia and nonhibernating rabbits during different temperatures (+3 degrees C to +37 degrees C).</AbstractText>Midhypothermia (+17 degrees C) resulted in nonuniform conduction slowing, increased dispersion of repolarization, shortened wavelength, and consequently enhanced VF induction in SA ground squirrels and rabbits. In contrast, wavelength was increased during hypothermia in WH hearts in which VF was not inducible at any temperature. In SA and rabbit hearts, but not in WH, conduction anisotropy was significantly increased by pacing acceleration, thus promoting VF induction during hypothermia. WH hearts maintained the same rate-independent anisotropic propagation pattern even at 3 degrees C. connexin 43 (Cx43) had more homogenous transmural distribution in WH ventricles as compared to SA. Moreover, Cx43 and N-cadherins (N-cad) densities as well as the percentage of their colocalization were significantly higher in WH compared to SA epicardium.</AbstractText>Rate-independent conduction anisotropy ratio, low dispersion of repolarization, and long wavelength-these are the main electrophysiological mechanisms of antiarrhythmic protection in hibernating mammalian species during hypothermia. This strategy includes the improved gap junction function, which is due to overexpression and enhanced colocalization of Cx43 and N-cad.</AbstractText> |
7,214 | Sodium channel blocker tests allow a clear distinction of electrophysiological characteristics and prognosis in patients with a type 2 or 3 Brugada electrocardiogram pattern. | Patients with a type 2 or 3 Brugada syndrome (BS) pattern and a negative sodium channel blocker challenge (SCBC) are not considered as affected. Their arrhythmic prognosis is generally considered good, but it has never been specifically evaluated.</AbstractText>The purpose of this study was to evaluate the arrhythmic prognosis in patients with a type 2 or 3 electrocardiogram (ECG) not converted to type 1 ECG during an SCBC.</AbstractText>Clinical data, 12-lead ECG, results of the SCBC and electrophysiological study (EPS), and follow-up were collected.</AbstractText>Among the 500 patients who underwent an SCBC in our institution, 158 displayed a type 2 or 3 ECG. After the SCBC, 93 (59%) had a type 1 ECG (positive group [PG]), whereas 65 (41%) remained negative (negative group [NG]). An EPS was performed in 31 (33%) PG patients and 15 (23%) NG patients. Ventricular fibrillation was induced in 21 PG patients (67%), whereas no patient in the NG was inducible (P <.001). During a follow-up of 37 +/- 17 months, no sudden death occurred. Three syncopes were observed in the NG versus one syncope, two ventricular tachycardias, and one appropriate shock in the PG.</AbstractText>This study demonstrates that the presence or absence of coved type ST-segment elevation during the SCBC denotes a profound electrophysiological difference as demonstrated by the absence of inducibility during EPS in the NG that may be responsible for the good prognosis of patients with a type 2 or 3 ECG pattern not converted to type 1.</AbstractText> |
7,215 | Seasonal and circadian distributions of ventricular fibrillation in patients with Brugada syndrome. | It is well-known that the incidence of ventricular tachyarrhythmias is the highest in winter and during the daytime in patients with structural heart disease. However, little is known about the seasonal and circadian distributions of ventricular fibrillation (VF) in patients with Brugada syndrome.</AbstractText>The aim of this study was to investigate seasonal and circadian distributions of VF in patients with Brugada syndrome.</AbstractText>We analyzed the data of appropriate shock episodes for VF recorded by an implantable cardioverter-defibrillator (ICD) in patients with Brugada syndrome.</AbstractText>Among 62 consecutive Brugada syndrome patients with an ICD (48 +/- 14 years, 58 males), 19 patients had at least one episode of an appropriate ICD shock due to VF during a mean follow-up of 70 +/- 36 months, and 98 episodes were evaluated as isolated VF. There was a significant peak between March and June (P = .03). As for the circadian variation, significantly more VF occurred from midnight to 6:00 (P <.0001). Electrical storms of VF occurred in seven patients. The seasonal and circadian variations of electrical storms were similar to those of the isolated VF episodes.</AbstractText>In patients with Brugada syndrome, there was a significant seasonal peak from spring to early summer and a significant circadian peak from midnight to early morning in terms of the occurrences of VF.</AbstractText> |
7,216 | Obesity and dysrhythmias. | In the United States, obesity has reached epidemic proportions. Results from the 2003-2004 National Health and Nutrition Examination Survey estimated that 66% of US adults are either overweight (body mass index [BMI] 25-30 kg/m(2)) or obese (BMI>30 kg/m(2)) as defined by the BMI cutoffs established by the World Health Organization. In the 1970s, only 15% of the US population between the ages of 20 and 74 years was categorized as obese. In 2003, approximately 32% of the adult population was obese. Obesity plays an important role in the evolution of cardiovascular disease. This article reviews the histopathophysiologic changes that occur in cardiac structure and function in response to obesity, explores the relationship between obesity and arrhythmias such as atrial fibrillation and sudden cardiac death, and analyzes electrocardiographic changes in an obese patient. |
7,217 | Downloadable algorithm to reduce inappropriate shocks caused by fractures of implantable cardioverter-defibrillator leads. | The primary method for monitoring implantable cardioverter-defibrillator lead integrity is periodic measurement of impedance. Sprint Fidelis leads are prone to pace-sense lead fractures, which commonly present as inappropriate shocks caused by oversensing.</AbstractText>We developed and tested an algorithm to enhance early identification of lead fractures and to reduce inappropriate shocks. This lead-integrity algorithm, which can be downloaded into presently implanted implantable cardioverter-defibrillators, alerts the patient and/or physician when triggered by either oversensing or excessive increases in impedance. To reduce inappropriate shocks, the lead-integrity algorithm increases the number of intervals to detect (NID) ventricular fibrillation when triggered. The lead-integrity algorithm was tested on data from 15 970 patients with Fidelis leads (including 121 with clinically diagnosed fractures) and 95 other fractured leads confirmed by analysis of returned product. The effect of the NID on inappropriate shocks was tested in 92 patients with 927 shocks caused by lead fracture. Increasing the NID reduced inappropriate shocks (P<0.0001). The lead-integrity algorithm provided at least a 3-day warning of inappropriate shocks in 76% (95% CI, 66 to 84) of patients versus 55% (95% CI, 43 to 64) for optimal impedance monitoring (P=0.007). Its positive predictive value was 72% for lead fractures and 81% for lead fractures or header-connector problems requiring surgical intervention. The false-positive rate was 1 per 372 patient-years of monitoring.</AbstractText>A lead-integrity algorithm developed for download into existing implantable cardioverter-defibrillators increases short-term warning of inappropriate shocks in patients with lead fractures and reduces the likelihood of inappropriate shocks. It is the first downloadable RAMware to enhance the performance of nominally functioning implantable cardioverter-defibrillators and the first implantable cardioverter-defibrillator monitoring feature that triggers real-time changes in ventricular fibrillation detection parameters to reduce inappropriate shocks.</AbstractText> |
7,218 | Defibrillation threshold testing: is it necessary during implantable cardioverter-defibrillator implantation? | Defibrillation threshold (DFT) testing has traditionally been a routine part of implantable cardioverter-defibrillator (ICD) implantation. DFT testing was developed in the early days of the ICD when failure of defibrillation was common, recipients had a high-risk of ventricular tachycardia (VT) or ventricular fibrillation (VF), and the only therapy for rapid VT or VF was a shock. However, modern ICD systems have such a high rate of successful defibrillation that many electrophysiologists now question whether DFT testing is still worthwhile. Studies found that long-term mortality was not higher among patients not undergoing DFT testing. Moreover, there was no survival difference between patients with a lower DFT and a higher DFT. Other studies have demonstrated that DFT testing poses some risk to the patient such as myocardial damage, embolic stroke in patient with atrial fibrillation and DFT testing-related death. If DFT testing is abandoned, more patients may have the opportunity to be treated with ICD, especially in regions with few or no electrophysiologists. It may be argued that other physicians, such as those currently implanting pacemakers, would more readily implant ICDs if not for the requirement of DFT testing. |
7,219 | Approaching regional left atrial function by tissue Doppler velocity and strain imaging. | Atrial function is an integral part for the proper performance of the circulatory system. Assessment of its haemodynamic and mechanical characteristics by use of non-invasive echocardiography, including tissue Doppler velocity and strain imaging, may provide a better insight into atrial function and its relationship with ventricular function. From an electromechanical perspective, this review summarizes not only the various methods for evaluating regional atrial function by tissue Doppler imaging, but also the normal findings in healthy subjects and the major clinical utilities in cardiac diseases, such as atrial fibrillation, ischaemic heart disease and heart failure. |
7,220 | Electro-anatomic mapping systems in arrhythmias. | Electroanatomic mapping systems have permitted and facilitated difficult interventional ablation procedures for more than a decade. Initially, their use has been in arrhythmias in which the ablation target is difficult to identify, such as ventricular tachycardias in structural heart disease, atypical atrial flutters, or arrhythmias in patients with complex congenital heart defects. In the recent years, electroanatomic mapping systems have also been used to guide catheter-based isolation of the pulmonary veins, an important component of the modern management of atrial fibrillation (AF). Electroanatomic mapping systems integrate three important functionalities, namely (i) non-fluoroscopic localization of electrophysiological catheters in three-dimensional (3D) space; (ii) analysis and 3D display of activation sequences computed from local or calculated electrograms, and 3D display of electrogram voltage ('scar tissue'); and (iii) integration of this 'electroanatomic' information with non-invasive images of the heart (mainly computed tomography or magnetic resonance images). Although better understanding and ablation of complex arrhythmias mostly relies on the 3D integration of catheter localization and electrogram-based information to illustrate re-entrant circuits or areas of focal initiation of arrhythmias, the use of electroanatomic mapping systems in AF is currently based on integration of anatomic images of the left atrium and non-fluoroscopic visualization of the ablation catheter. Their use in the treatment of AF is mainly driven by safety considerations such as shorter fluoroscopy and procedure times, or visualization of cardiac (pulmonary veins) and extra-cardiac (oesophagus) structures that need to be protected during the procedure. In the future, the use of magnetic resonance images, and potentially of high-quality 3D ultrasound images, could provide anatomic information without ionizing radiation and may be helpful to visualize left atrial scar tissue. |
7,221 | [Bouts of chest pain]. | We report on a 46-year-old man with vasospastic angina. The differential diagnosis, the eventful course of the patient and in particular the clinical image with diagnostic approach, therapy and prognosis of vasospastic angina are discussed. |
7,222 | Recurrent ventricular fibrillation caused by coronary artery spasm leading to implantable cardioverter defibrillator implantation. | Coronary artery spasm has been known to induce ischaemia and ventricular arrhythmias. We present a case of recurrent ventricular fibrillation caused by spasm-associated transmural myocardial ischaemia. During an intra-coronary acetylcholine provocation test, severe coronary spasm could be induced. The patient was treated with a hybrid approach of medication and an implantable defibrillator. |
7,223 | Pediatric cardiopulmonary resuscitation: advances in science, techniques, and outcomes. | More than 25% of children survive to hospital discharge after in-hospital cardiac arrests, and 5% to 10% survive after out-of-hospital cardiac arrests. This review of pediatric cardiopulmonary resuscitation addresses the epidemiology of pediatric cardiac arrests, mechanisms of coronary blood flow during cardiopulmonary resuscitation, the 4 phases of cardiac arrest resuscitation, appropriate interventions during each phase, special resuscitation circumstances, extracorporeal membrane oxygenation cardiopulmonary resuscitation, and quality of cardiopulmonary resuscitation. The key elements of pathophysiology that impact and match the timing, intensity, duration, and variability of the hypoxic-ischemic insult to evidence-based interventions are reviewed. Exciting discoveries in basic and applied-science laboratories are now relevant for specific subpopulations of pediatric cardiac arrest victims and circumstances (eg, ventricular fibrillation, neonates, congenital heart disease, extracorporeal cardiopulmonary resuscitation). Improving the quality of interventions is increasingly recognized as a key factor for improving outcomes. Evolving training strategies include simulation training, just-in-time and just-in-place training, and crisis-team training. The difficult issue of when to discontinue resuscitative efforts is addressed. Outcomes from pediatric cardiac arrests are improving. Advances in resuscitation science and state-of-the-art implementation techniques provide the opportunity for further improvement in outcomes among children after cardiac arrest. |
7,224 | Late reoperations for Fontan patients: state of the art invited review. | Conversion of the atriopulmonary Fontan to a total cavopulmonary extracardiac connection with concomitant arrhythmia surgery and pacemaker placement is a safe and efficacious procedure for this patient population. From 1994 to 2007 a total of 118 patients have undergone this procedure with one (0.8%) early and nine (7.6%) late deaths. During the course of our experience with Fontan conversion our surgical strategy has evolved to include various ablative techniques to treat macro re-entrant atrial tachycardia, focal (automatic) atrial tachycardia, atrioventricular nodal reentry tachycardia, atrial tachycardia due to accessory connections, atrial fibrillation, and ventricular tachycardia. The various mechanisms that we use to treat the underlying atrial arrhythmias are described in this review. We have also encountered patients with variations of the Fontan and other complex anatomic and pathophysiologic aberrations who were not amenable to standard takedown and ablative procedures. We describe those circumstances and the solutions we found to treat those patients. |
7,225 | Intravenous infusion of bone marrow mesenchymal stem cells improves brain function after resuscitation from cardiac arrest. | Allogeneic bone marrow mesenchymal stem cells were previously shown to improve myocardial function when administered intravenously after resuscitation from cardiac arrest in rats. Coincidental evidence of improved brain function prompted the present study.</AbstractText>Prospective, randomized, controlled study.</AbstractText>University-affiliated research institute.</AbstractText>Male Sprague-Dawley rats.</AbstractText>Using an established model in 20 male Sprague-Dawley rats in which 6 mins of untreated cardiac arrest was followed by cardiopulmonary resuscitation, animals were randomized to receive 5 x 10(6) mesenchymal stem cells labeled with PKH26 in phosphate buffer solution or phosphate buffer solution alone as a placebo at 2 hrs after restoration of spontaneous circulation. The stem cells or buffer diluent were injected into a catheter advanced from the jugular vein into the right atrium.</AbstractText>Outcome measurements in addition to 35-day survival included somatosensor testing of capability for removal of an adhesive patch applied to both front paws, testing of motor function using a rotating cylinder, and observational scoring of the severity of neurologic impairment. Labeled mesenchymal stem cells were subsequently identified and counted in 5 microm sections obtained from defined sites in the harvested brain. Immunohistochemistry was used to identify neural cells differentiation of mesenchymal stem cells. Adhesive removal, motor function test, neurologic severity score, and 35-day survival were each significantly improved in comparison with control animals. Labeled mesenchymal stem cells were identified in the hippocampus, cortex, pons, medulla, and cerebellum and expressed protein markers phenotypic neural cells.</AbstractText>Mesenchymal stem cells injected into the right atrium of rats after resuscitation from cardiac arrest were identified in brains harvested 35 days later. Brain function was significantly improved. Accordingly, venous injection of mesenchymal stem cells after cardiopulmonary resuscitation has promise of minimizing the severity of postresuscitation neurologic impairment.</AbstractText> |
7,226 | Transthoracic application of electrical cardiopulmonary resuscitation for treatment of cardiac arrest. | Observational studies have shown that muscular stimulation contracting the thoracic cage may produce coronary perfusion pressures equal to manual chest compressions. This study examined electrical cardiopulmonary resuscitation for coronary perfusion pressures during ventricular fibrillation in a porcine model of cardiac arrest.</AbstractText>Prospective randomized controlled study.</AbstractText>University affiliated research institute.</AbstractText>Domestic male pigs.</AbstractText>In seven domestic male pigs (40 +/- 2 kg), ventricular fibrillation was induced electrically and untreated for 10 secs. For each ventricular fibrillation episode, one of 16 electrical cardiopulmonary resuscitation stimulation protocols (pulse trains) or manual chest compression was applied. Each compression protocol was applied for 20 secs, followed by a defibrillation shock. The experimental procedure was performed across one or more randomized complete blocks. The electrical cardiopulmonary resuscitation pulse trains were defined by four two-level factors: pulse width (0.15 and 7.5 msec), pulse period (15 and 30 msec), train width (50 and 200 msec), and train rate (60 or 120 compressions per min). Pulse trains comprised two groups, based on pulse width (skeletal-based, 0.15 msec; cardiac-based, 7.5 msec).</AbstractText>Train width was the significant design parameter for producing efficacious levels of coronary perfusion pressures for the skeletal-based electrical cardiopulmonary resuscitation pulse trains (p = 0.02). Both train width and train rate were significant design parameters for producing efficacious levels of coronary perfusion pressures for the cardiac-based electrical cardiopulmonary resuscitation pulse trains (p < 0.001, p = 0.5, respectively). Optimal skeletal-based and cardiac-based electrical cardiopulmonary resuscitation pulse trains were significantly better than ventricular fibrillation (p = 0.01, p = 0.01, respectively) and equivalent to manual chest compression (p = 0.2, p = 0.7, respectively) for sufficient coronary perfusion pressure levels.</AbstractText>Optimal skeletal-based and cardiac-based electrical cardiopulmonary resuscitation pulse train parameters generated levels of coronary perfusion pressure significantly greater than ventricular fibrillation and comparable with manual chest compression over a short interval of untreated cardiac arrest.</AbstractText> |
7,227 | Targeting mitochondria for resuscitation from cardiac arrest. | Reversal of cardiac arrest requires reestablishment of aerobic metabolism by reperfusion with oxygenated blood of tissues that have been ischemic for variable periods of time. However, reperfusion concomitantly activates a myriad of pathogenic mechanisms causing what is known as reperfusion injury. At the center of reperfusion injury are mitochondria, playing a critical role as effectors and targets of injury. Studies in animal models of ventricular fibrillation have shown that limiting myocardial cytosolic Na+ overload attenuates mitochondrial Ca2+ overload and maintains oxidative phosphorylation, which is the main bioenergetic function of mitochondria. This effect is associated with functional myocardial benefits such as preservation of myocardial compliance during chest compression and attenuation of myocardial dysfunction after return of spontaneous circulation. Additional studies in similar animal models of ventricular fibrillation have shown that mitochondrial injury leads to activation of the mitochondrial apoptotic pathway, characterized by the release of cytochrome c to the cytosol, reduction of caspase-9 levels, and activation of caspase-3 coincident with marked reduction in left ventricular function. Cytochrome c also "leaks" into the bloodstream attaining levels that are inversely proportional to survival. These data indicate that mitochondria play a key role during cardiac resuscitation by modulating energy metabolism and signaling apoptotic cascades and that targeting mitochondria could represent a promising strategy for cardiac resuscitation. |
7,228 | Intra-arrest rapid head cooling improves postresuscitation myocardial function in comparison with delayed postresuscitation surface cooling. | To compare resuscitation outcomes and myocardial function among intra-arrest head cooling, delayed surface cooling, and uncooled controls.</AbstractText>Prospective animal study.</AbstractText>University-affiliated animal research laboratory.</AbstractText>Twenty-four male domestic pigs.</AbstractText>Ventricular fibrillation remained untreated for 10 mins after which animals were assigned into three groups: 1) intra-arrest head cooling, 2) postresuscitation surface cooling, and 3) uncooled controls. Head cooling by evaporative perfluorochemical began coincident with the start of cardiopulmonary resuscitation and continued for a total of 4 hrs. Surface cooling using a cooling blanket began at 2 hrs after return of spontaneous circulation and continued for 8 hrs. Control animals were treated identically with the exception for cooling.</AbstractText>Return of spontaneous circulation was achieved in eight of eight head-cooled animals, in seven of eight surface-cooled animals, and in seven of eight of controls. Myocardial functions measured by transthoracic echocardiography were significantly better in the head-cooled animals than in surface-cooled and controls. All head-cooled animals survived for more than 96 hrs. This contrasted with six of eight survivors after surface cooling, and only two of eight among controls.</AbstractText>Both intra-arrest head cooling and delayed surface cooling improved postresuscitation myocardial dysfunction. The beneficial effects were greatest with head cooling initiated with cardiopulmonary resuscitation.</AbstractText> |
7,229 | A comparison between head cooling begun during cardiopulmonary resuscitation and surface cooling after resuscitation in a pig model of cardiac arrest. | Employing transnasal head-cooling in a pig model of prolonged ventricular fibrillation, we compared the effects of 4 hrs of head-cooling started during cardiopulmonary resuscitation with those of 8 hrs of surface-cooling started at 2 hrs after resuscitation on 96-hr survival and neurologic outcomes.</AbstractText>Prospective controlled animal study.</AbstractText>University-affiliated research laboratory.</AbstractText>Domestic pigs.</AbstractText>Twenty-four male pigs were subjected to 10 min of untreated ventricular fibrillation followed by 5 min of cardiopulmonary resuscitation. In the head-cooling group, hypothermia was started with cardiopulmonary resuscitation and continued for 4 hrs after resuscitation. In the surface-cooling group, systemic hypothermia with a cooling blanket was started, in accord with current clinical practices, at 2 hrs after resuscitation and continued for 8 hrs. Methods in the control animal studies were identical except for temperature interventions.</AbstractText>All animals were resuscitated except for one animal in each of the surface-cooling and control groups. After 5 min of cardiopulmonary resuscitation, jugular vein temperature was significantly decreased in the head-cooled animals. However, there were no differences in pulmonary artery temperatures among the three groups at that time. Nevertheless, both head-cooled and surface-cooled animals had an improved 96-hr survival after resuscitation. Significantly better neurologic outcomes were observed in early head-cooled animals in the first 3 days after resuscitation.</AbstractText>Early head-cooling during cardiopulmonary resuscitation continuing for 4 hrs after resuscitation produced favorable survival and neurologic outcomes in comparison with delayed surface-cooling of 8 hrs duration.</AbstractText> |
7,230 | Myocardial microcirculatory dysfunction after prolonged ventricular fibrillation and resuscitation. | The etiology of postresuscitation myocardial stunning is unknown but is thought to be related to either ischemia occurring during cardiac arrest and resuscitation efforts and/or reperfusion injury after restoration of circulation. A potential common pathway for postischemia/reperfusion end-organ dysfunction is microvascular injury. We hypothesized that myocardial microcirculatory function is markedly abnormal in the postresuscitation period.</AbstractText>In vivo study of myocardial microvascular function.</AbstractText>University animal laboratory.</AbstractText>Five swine (25 +/- 2 kg).</AbstractText>Measurements before and after cardiac arrest and resuscitation.</AbstractText>Baseline data were not different among the five subjects. Left ventricular ejection fraction was significantly lower at all postresuscitation time periods (p < .05), reaching a nadir of 19% at 1 hr postresuscitation. Cardiac output declined following fibrillation and resuscitation and was significantly lower than baseline at 1 and 4 hrs postresuscitation (p < .05). Prearrest coronary flow reserve, a ratio of normal to maximal intracoronary flow velocity, was 3.4 ("normal" ratio is 2:4), but was below normal (<2) throughout the 4-hr post resuscitation period (p < .05).</AbstractText>This in vivo study showed that normal myocardial microcirculatory function is quickly lost after prolonged ventricular fibrillation and resuscitation. As early as 30 min postresuscitation the myocardial microcirculatory function is less than 50% of its prearrest baseline level. This dysfunction persists for at least 4 hrs. During the postresuscitation period, both left ventricular ejection fraction and cardiac output decline from their prearrest levels. No cause and effect relationship was proven, but a parallel decline in left ventricular function and coronary flow reserve is evident.</AbstractText> |
7,231 | The amplitude spectrum area correctly predicts improved resuscitation and facilitated defibrillation with head cooling. | When systemic hypothermia was maintained before inducing cardiac arrest, the likelihood of successful defibrillation and meaningful survival was increased. When hypothermia is induced during cardiopulmonary resuscitation, mortality is also improved. With the introduction of the amplitude spectrum area as a predictor of the success of electrical defibrillation, we investigated the effect of preferential head cooling initiated coincident with cardiopulmonary resuscitation on amplitude spectrum area as a predictor. We hypothesized that rapid head cooling initiated coincident with cardiopulmonary resuscitation improves amplitude spectrum area, and therefore is predictive of successful defibrillation.</AbstractText>Prospective randomized controlled study.</AbstractText>University-affiliated research institute.</AbstractText>Domestic pigs.</AbstractText>Sixteen pigs, weighing 40.6 +/- 1.4 kg, were randomized to the hypothermia (n = 8), or control (n = 8) group. Ventricular fibrillation was induced and untreated for 10 mins. Cardiopulmonary resuscitation was then initiated for 5 mins followed by attempted defibrillation with a biphasic 150-J electric shock. Coincident with starting cardiopulmonary resuscitation, hypothermia was induced with evaporative intranasal cooling using a perfluorochemical. If spontaneous circulation was not restored after defibrillation, cardiopulmonary resuscitation was resumed for 1 min before the next defibrillation attempt until the animal was either successfully resuscitated or for a total of 15 mins. The target core temperature was 34 degrees C. Control animals were identically treated except for hypothermia.</AbstractText>Five seconds of ventricular fibrillation waveform were recorded immediately preceding delivery of a shock. The ventricular fibrillation waveforms were analyzed using the amplitude spectrum area algorithm. A smaller epinephrine dose (60 +/- 32.1 vs. 30 +/- 0 mg/mL, p = .01) and shorter cardiopulmonary resuscitation duration (365 +/- 42 sec vs. 600 +/- 243 sec, p = .01) were required to achieve return of spontaneous circulation in the hypothermia group, compared with control. Five minutes after starting cardiopulmonary resuscitation, head temperature was reduced from 38 degrees C to 34 degrees C in the hypothermia group (p = .028). Hypothermia improved the success of electrical shocks before return of spontaneous circulation (88 +/- 18% vs. 66 +/- 19%, p = .034). Both the amplitude spectrum area values of initial shock (26.1 +/- 5.3 vs. 21.4 +/- 2.16 mV-Hz, p = .049) and total shocks (26.1 +/- 5.3 vs. 21.4 +/- 2.16 mV-Hz, p = .006) were significantly higher in the hypothermia group than control.</AbstractText>Amplitude spectrum area served as a useful predictor for improved resuscitation and facilitated defibrillation in the setting of rapid head cooling initiated coincident with cardiopulmonary resuscitation.</AbstractText> |
7,232 | From laboratory science to six emergency medical services systems: New understanding of the physiology of cardiopulmonary resuscitation increases survival rates after cardiac arrest. | The purpose of this study is to: 1) describe a newly mechanism of blood flow to the brain during cardiopulmonary resuscitation using the impedance threshold device in a piglet model of cardiac arrest, and 2) describe the survival benefits in humans of applying all of the highly recommended changes in the 2005 guidelines related to increasing circulation during cardiopulmonary resuscitation, including use of the impedance threshold device, from six emergency medical services systems in the United States.</AbstractText>Animal studies prospective trial with each piglet serving as its own control. Historical controls were used for the human studies.</AbstractText>Piglets and patients with out-of-hospital cardiac arrest.</AbstractText>Piglets (10-12 kg) were treated with an active (n = 9) or sham (n = 9) impedance threshold device after 6 mins of ventricular fibrillation. Humans were treated with cardiopulmonary resuscitation per the American Heart Association 2005 guidelines and the impedance threshold device.</AbstractText>The primary endpoint in the piglet study was carotid blood flow which increased from 59 mL/min without an impedance threshold device to 91 mL/min (p = 0.017) with impedance threshold device use. Airway pressures during the chest recoil phase decreased from -0.46 mm Hg to -2.59 mm Hg (p = 0.0006) with the active impedance threshold device. Intracranial pressure decreased more rapidly and to a greater degree during the decompression phase of cardiopulmonary resuscitation with the active impedance threshold device. Humans: Conglomerate quality assurance data were analyzed from six emergency medical services systems in the United States serving a population of approximately 3 million people. There were 920 patients treated for cardiac arrest after implementation of the 2005 American Heart Association guidelines, including impedance threshold device use, and 1750 patients in the control group during the year before implementation. Demographics were similar between the two groups. Survival to hospital discharge was 9.3% in the control group versus 13.6% in the intervention group. The odds ratio, 95% confidence interval, and p value were 1.54 (1.19-1.99) and p = 0.0008, respectively. This survival advantage was conferred to patients with a presenting cardiac arrest rhythm of ventricular fibrillation (28.5% vs. 18.0%, p = 0.0008).</AbstractText>Use of the impedance threshold device in piglets increased carotid blood flow and coronary and cerebral perfusion pressures and reduced intracranial pressure during the decompression phase of cardiopulmonary resuscitation at a faster rate than controls, resulting in a longer duration of time when intracranial pressures are at their nadir. Patients in six emergency medical services systems treated with the impedance threshold device together with the renewed emphasis on more compressions, fewer ventilations, and complete chest wall recoil had a nearly 50% increase in survival rates after out-of-hospital cardiac arrest compared with historical controls.</AbstractText> |
7,233 | Determinants of plasma NT-pro-BNP levels in patients with atrial fibrillation and preserved left ventricular ejection fraction. | The present study aimed to investigate the clinical and echocardiographic determinants of plasma NT-pro-BNP levels in patients with atrial fibrillation (AF) and preserved left ventricular ejection fraction (LVEF).</AbstractText>NT-pro-BNP levels were measured in 45 patients with paroxysmal AF, 41 patients with permanent AF and 48 controls.</AbstractText>NT-pro-BNP levels were found significantly elevated in patients with paroxysmal (215+/-815 pg/ml) and permanent AF (1,086+/-835 pg/ml) in relation to control population (86.3+/-77.9 pg/ml) (P<0.001). According to the univariate linear regression analysis, age, hypertension, beta-blocker use, left atrial diameter (LAD), LVEF and AF status (paroxysmal or permanent or both) were significantly associated with NT-pro-BNP levels (P<0.05). In multiple linear regression analysis, LVEF (B coefficient: -53.030; CI: -95.738 to -10.322; P: 0.015) and LAD (B coefficient: 285.858; CI: 23.731-547.986; P: 0.033) were significant and independent determinants of NT-pro-BNP levels.</AbstractText>Plasma NT-pro-BNP levels were significantly higher in patients with paroxysmal and permanent AF compared to those with sinus rhythm in the setting of preserved left ventricular systolic function. LVEF and LAD were independent predictors of NT-pro-BNP levels.</AbstractText> |
7,234 | Cardiac arrhythmia during propofol sedation. | Recent articles have described the increasing frequency of use of propofol as a sedating agent in the ED, and praise the safety profile of propofol when used in this manner. We describe a patient who developed torsade de pointes followed by ventricular fibrillation while undergoing propofol sedation for closed reduction of a mid-shaft fracture of the tibia and fibula. Possible reasons for the event are discussed, and suggestions are made for areas of further research. |
7,235 | T-wave alternans: reviewing the clinical performance, understanding limitations, characterizing methodologies. | Accurate recognition of individuals at higher immediate risk of sudden cardiac death (SCD) is still an open question. The fortuitous nature of acute cardiovascular events just does not seem to fit the well-known model of ventricular tachycardia/fibrillation induction in a static arrhythmogenic substrate by a synchronous trigger. On the mechanism of SCD, a dynamical electrical instability would better explain the rarity of the simultaneous association of a correct trigger and an appropriate cardiac substrate. Several studies have been conducted trying to measure this cardiac electrical instability (or any valid surrogate) in an ECG beat stream. Among the current possible candidates we can number QT prolongation, QT dispersion, late potentials, T-wave alternans (TWA), and heart rate turbulence. This article reviews the particular role of TWA in the current cardiac risk stratification scenario. TWA findings are still heterogeneous, ranging from very good to nearly null prognostic performance depending on the clinical population observed and clinical protocol in use. To fill the current gaps in the TWA base of knowledge, practitioners, and researchers should better explore the technical features of the several technologies available for TWA evaluation and pay greater attention to the fact that TWA values are responsive to several factors other than medications. Information about the cellular and subcellular mechanisms of TWA is outside the scope of this article, but the reader is referred to some of the good papers available on this topic whenever this extra information could help the understanding of the concepts and facts covered herein. |
7,236 | [Short time ECG signal analysis based on the reconstruction of phase space]. | Based on the reconstruction of two-dimension phase space of time series of short ECG signals, the variation of the strange attractor geometry is described and two indices, VMI and VAI, are derived in this paper. The two indices can distinguish clearly the ECG signals of sinus rhythm, tachycardia and ventricular fibrillation. Stable results of VMI and VAI can be obtained by analyzing ECG signals of several seconds. They are expected to be used in the development of medical instruments for a fast realtime display of analysis results. |
7,237 | Acute coronary syndromes in patients with prosthetic heart valves-a case-series. | There are few reports regarding acute coronary syndromes (ACS) in patients with prosthetic heart valves (PHV), mostly attributing the ACS to a PHV-derived coronary embolus.</AbstractText>To characterize a case-series of ACS patients with PHV.</AbstractText>All patients in our institution with previous PHV surgery and ACS during 1996-2005 were retrospectively analysed.</AbstractText>We identified 40 patients from the 15,878 patient database, whose mean age was 72.5 +/- 12.5 years and of whom 21 were male. The majority (n=28) had mechanical valves; 24 patients (60%) had an aortic prosthetic valve, 9 patients (22.5%) had a mitral valve prosthesis and 7 patients (17.5%) had both. The majority of patients had > or = 2 risk factors for atherosclerotic disease. The median time from the PHV implantation to the subsequent ACS was 8.0 (4.7-12.1) years. Most patients had non-ST-segment elevation ACS rather than ST-segment elevation ACS (32 patients versus 8 patients). 12 patients (30%) had moderate to severe left ventricular dysfunction and 2 of them presented with cardiogenic shock. Atrial fibrillation on hospital admission was noted in 13 patients (32.5%). ACS management included coronary angiography in 32 patients (80%) which revealed coronary disease in 93%. Only 2 patients had normal coronary arteries and PHV-derived coronary emboli. The most frequent in-hospital complication was heart failure (n=11, 27.5%).</AbstractText>Patients with PHV and ACS are a rare subgroup, more likely to be elderly with risk factors for atherosclerotic disease and to present with non-ST-segment-elevation ACS. The pathogenesis for ACS is commonly coronary atherosclerotic disease rather than PHV-derived emboli.</AbstractText> |
7,238 | Safety of the novel atrial-selective K+-channel blocker AVE0118 in experimental heart failure. | Congestive heart failure (CHF) is often associated with atrial fibrillation. The safety of many antiarrhythmic drugs in CHF is limited by proarrhythmic effects. We aimed to assess the safety of a novel atrial-selective K(+)-channel blocker AVE0118 in CHF compared to a selective (dofetilide) and a non-selective IKr blocker (terfenadine). For the induction of CHF, rabbits (n = 12) underwent rapid right ventricular pacing (330-380 bpm for 30 days). AVE0118 (1 mg/kg) dofetilide (0.02 mg/kg) and terfenadine (2 mg/kg) were administered in baseline (BL) and CHF. A six-lead ECG was continuously recorded digitally for 30 min after each drug administration. At BL, dofetilide and terfenadine significantly prolonged QTc interval (218 +/- 30 ms vs 155 +/- 8 ms, p = 0.001 and 178 +/- 23 ms vs. 153 +/- 12 ms, p = 0.01, respectively) while QTc intervals were constant after administration of AVE0118 (p = n.s.). In CHF, dofetilide and terfenadine caused torsades de pointes and symptomatic bradycardia, respectively, and prolonged QTc interval (178 +/- 30 ms vs. 153 +/- 14 ms, p = 0.02 and 157 +/- 7 ms vs. 147 +/- 10 ms, p = 0.02, respectively) even at reduced dosages, whereas no QTc-prolongation or arrhythmia was observed after full-dose administration of AVE0118. In conclusion, atrial-selective K(+)-channel blockade by AVE0118 appears safe in experimental CHF. |
7,239 | Recurrent perimesencephalic subarachnoid hemorrhage during antithrombotic therapy. | In patients with non-aneurysmal perimesencephalic hemorrhage, spontaneous rebleeding does not occur. The lack of reported recurrences may lead to less cautious administration of antithrombotic therapy.</AbstractText>Case report.</AbstractText>A 57-year-old woman with a perimesencephalic pattern of hemorrhage and negative CT angiography was treated with carbasalate calcium and intravenous heparin because of an acute coronary syndrome. Three days after installment of this antithrombotic therapy she experienced a recurrent perimesencephalic hemorrhage leading to hydrocephalus and a decrease in consciousness. She died the same day as a result of ventricular fibrillation.</AbstractText>In the early phase after perimesencephalic hemorrhage, anticoagulant therapy may lead to rebleeding. The risks and benefits of antithrombotic therapy should be carefully weighed in patients with a perimesencephalic pattern of hemorrhage and negative CT angiography.</AbstractText> |
7,240 | [Impact of electrical shock waveform and paddle positions on efficacy of direct current cardioversion for atrial fibrillation]. | Direct-current electrical cardioversion is the main method for the conversion of atrial fibrillation. Its success depends on many factors. In several studies, biphasic shock waveforms have been demonstrated to be superior to monophasic shocks for termination of atrial fibrillation; however, information about impact of paddle position is controversial. Initial energy level is an object of discussions. The aim of the study was to compare a truncated exponential biphasic waveform with monophasic damped sine waveform and antero-lateral with antero-posterior paddle positions for cardioversion of atrial fibrillation, to determine its impact on early reinitiation of atrial fibrillation.</AbstractText>A total of 224 consecutive patients with atrial fibrillation underwent electrical cardioversion with biphasic (Bi, n=112) or monophasic (Mo, n=112) shock waveform in a randomized fashion. The position of hand-held paddle electrodes was randomly selected in both groups to be anterior-lateral and anterior-posterior. Energies used were 100-150-200-300-360 J (Bi) or 100-200-300-360 J (Mo). If monophasic shock of 360 J was ineffective, we used biphasic shock of 360 J. Early recurrent atrial fibrillation (ERAF) was defined as a relapse of atrial fibrillation within 2 min after a successful cardioversion, acute recurrent - within 24 h.</AbstractText>Two study groups (Bi vs Mo) did not differ with regard to age, body mass index, duration of AF episode (mean 98+/-147 days for the Bi group and 80+/-93 days for the Mo group, P=0.26), underlying heart disease, left atrial diameter, left ventricular ejection fraction. In the Mo group, more patients used amiodarone (59.82% vs 41.97%, P=0.002), in the Bi group more patients used propafenone (16.07% vs 8.93%, P=0.033). Cardioversion success rate was 97.32% in the Bi group and 79.46% in the Mo group (P<0.001). After biphasic shock of 360 J in Mo group, the cumulative success rate was 99.11%. Mean delivered energy and mean number of shocks were significantly lower in the Bi group (198.5+/-204.4 J, 1.5+/-0.9 shocks vs 489.1+/-464.2 J, 2.4+/-1.5 shocks). The efficacy of first shock was 66.96% in the Bi group and 37.5% in the Mo group (P<0.0001). Incidence of ERAF was 4.46% in both groups. Paddle position had no impact on efficacy of cardioversion and ERAF.</AbstractText>For the cardioversion of atrial fibrillation, biphasic shock waveform has a higher success rate than monophasic shock waveform. We did not observe the influence of paddle positions on efficacy of cardioversion. Shock waveform and paddle position had no impact on ERAF. We recommend starting with biphasic energy of 150 J and monophasic of not less than 200 J for cardioversion of atrial fibrillation.</AbstractText> |
7,241 | Defibrillation testing and early neurologic outcome. | During implantable cardioverter-defibrillator (ICD) implantation, ventricular defibrillation testing (DFT) is considered a standard procedure. This procedure often requires multiple ventricular fibrillation (VF) inductions. These repeated short episodes of circulatory arrest with global cerebral ischemia may cause neurological damage. In the present study, patients undergoing initial ICD implantation and limited induction of VF for defibrillation safety margin testing were evaluated for pre- and postoperative cognitive and neurologic functions. In addition, the serum neuron specific enolase (NSE) level, which is a biochemical marker of cerebral injury, was evaluated. The study was performed on 16 patients undergoing initial elective transvenous insertion of an ICD. A neurologic examination and cognitive assessment tests were performed 24 to 48 hours before and after ICD. NSE was determined before (NSE 1) and at the end of the surgery (NSE 2), as well as 2 hours (NSE 3), 24 hours (NSE 4), and 48 hours (NSE 5) after implantation. A total of 29 internal shocks (average, 1.8 +/- 0.4) with energy ranging from 14 to 41 J (mean, 20 +/- 5; median, 20 J ) were delivered in the ICD group patients. In one patient, 3 external (50, 200 and 360 J) shocks were required for fast VT induced during ICD lead positioning. The mean duration of VF was 10 +/- 4 seconds and the mean cumulative time in VF was 16 +/- 5 seconds. The mean recovery time between VFs was 5.3 +/- 0.6 minutes. NSE levels were not different from the baseline at any time point in the patients of the group that completed the 48-hour observation period (P > 0.05). The patients did not report any new neurological symptoms after ICD implantation, and repeat examination after the procedure showed no abnormal findings other than those detected in the previous one. There were no statistically significant differences between the preoperative and postoperative scores obtained in the cognitive assessment. Single or two VF inductions and the brief arrest of cerebral circulation during ICD implantation are not associated with permanent neurological injury. However, further studies are needed to confirm this finding. |
7,242 | Atrial pacing, the forgotten pacing mode. | In patients with sick sinus syndrome and normal atrioventricular conduction, physiological pacing can be accomplished with either a single chamber atrial pacemaker AAI/R or a dual chamber pacemaker DDD/R. The single chamber device has the advantages of simpler implantation and lower initial costs, while the dual chamber device offers protection in case atrioventricular conduction disturbances develop in the future. When rigorous attention is paid to the pre-implantation selection criteria, the incidence of reported second- or third-degree atrioventricular block varied between 0.4 and 1.8% per annum. Medical practice, however, has shifted to predominant implantation of DDD/R pacemakers in more than 95% of patients with sick sinus syndrome. Recent publications have reported an increase in left atrial diameter, decrease in left ventricular fractional shortening and increased incidence of atrial fibrillation in patients with DDD/R pacing as compared with patients with single chamber atrial devices. These changes were proportional to the percentage of ventricular paced beats.New algorithms in dual chamber devices have been developed in order to minimise ventricular stimulation. These are being evaluated at present. In my opinion there is still a place for atrial pacing in selected patients with sick sinus syndrome with a minimum risk of developing complete atrioventricular block. (Neth Heart J 2008;16(Suppl1):S25-S27.). |
7,243 | Atrial Fibrillation and Congestive Heart Failure: should we aim to control the heart's rate or its rhythm? | The Atrial Fibrillation and Congestive Heart Failure trial, which was conducted in patients with a reduced left ventricular ejection fraction, demonstrates that prognosis is independent of whether treatment is targeted towards controlling the heart's rate or its rhythm. The study also showed that other factors, such as use of beta-blockers, angiotensin-converting-enzyme inhibitors, angiotensin-receptor blockers, oral anticoagulants, and implantable cardioverter-defibrillators, can have a major influence on prognosis. Antiarrhythmic drugs (primarily amiodarone) were well tolerated, and adequate rate control was achieved with adjusted doses of beta-blockers combined with digoxin. Future studies should focus on the clinical importance of radiofrequency ablation for atrial fibrillation, versus that of traditional approaches to treatment. |
7,244 | The early minutes of in-hospital cardiac arrest: shock or CPR? A population based prospective study. | In the early minutes of cardiac arrest, timing of defibrillation and cardiopulmonary resuscitation during the basic life support phase (BLS CPR) is debated. Aims of this study were to provide in-hospital incidence and outcome data, and to investigate the relation between outcome and time from collapse to defibrillation, time to BLS CPR, and CPR quality.</AbstractText>Resuscitation attempts during a 3-year period at St. Olav's University Hospital (960 beds) were prospectively registered. The times between collapse and initiation of BLS CPR, and defibrillation were determined. CPR quality was assessed by the resuscitation team. The relation between these variables and outcome (short term survival and discharge) was explored using non-parametric correlation and logistic regression.</AbstractText>CPR was started in a total of 223 arrests, an incidence of 77 episodes per 1000 beds per year. Return of spontaneous circulation occurred in 40%, and 29 patients (13%) survived to discharge. Median time from collapse to BLS CPR was 1 minute; CPR was judged to be of good quality in half of the episodes. CPR during the first 3 minutes in ventricular fibrillation (VF/VT) was negatively associated with survival, but later proved beneficial. For patients with non-shockable rhythms, we found no association between outcome and time to BLS or CPR quality.</AbstractText>Our findings indicate that defibrillation should have priority during the first 3 minutes of VF/VT. Later, patients benefit from CPR in conjunction with defibrillation. Patients presenting with non-shockable rhythms have a grave prognosis, and the outcome was not associated with time to BLS or CPR quality.</AbstractText> |
7,245 | Cardiac arrest with pulseless electrical activity associated with methylphenidate in an adolescent with a normal baseline echocardiogram. | Recent concerns of adverse cardiac events associated with drugs used to treat attention-deficit-hyperactivity disorder (ADHD) have prompted debate over whether these drugs are truly safe. We describe a 17-year-old boy with a normal baseline echocardiogram who had been taking methylphenidate for ADHD for 18 months and experienced cardiac arrest. Emergency personnel attempted to resuscitate him, performing defibrillation twice for ventricular fibrillation, with subsequent pulseless electrical activity. The patient was immediately taken to the hospital where he received continued resuscitation, intravenous boluses of cardiac drugs, and additional defibrillation. A persistent pulsatile rhythm returned about 2 minutes after arrival. Overall, the patient was pulseless for 22 minutes. Emergency cardiac catheterization revealed wall motion abnormalities without coronary lesions. He was mechanically ventilated and was transferred to the intensive care unit, where he remained comatose. Neurologic studies performed the next day revealed diffuse encephalopathy due to anoxic brain injury. An echocardiogram on day 3 showed slightly improved left ventricular systolic function, which improved further by day 15. As the patient did not regain purposeful movement, he was discharged to a rehabilitation facility on day 33. The patient's methylphenidate therapy had been started at an appropriate dose of 18 mg/day and titrated over a period of 3 months up to 36 mg/day, which he continued until the event. The drug had been discontinued on admission, was not restarted, and for the next 2 years, the patient experienced no further cardiac events, although his severe mental deficiencies persisted. Use of the Naranjo adverse drug reaction probability scale indicated a probable relationship (score of 6) between the patient's adverse cardiac event and methylphenidate. To our knowledge, this is the first case report of a patient with documentation of a normal baseline echocardiogram who experienced cardiac arrest with pulseless electrical activity while taking methylphenidate for ADHD. Clinicians should be aware that despite performing a comprehensive cardiac examination before prescribing a stimulant for ADHD, patients may still be at risk for a serious cardiac event. The risks and benefits of using these drugs must be assessed by clinicians, parents, and patients. |
7,246 | Role of microvolt T-wave alternans in assessment of arrhythmia vulnerability among patients with heart failure and systolic dysfunction: primary results from the T-wave alternans sudden cardiac death in heart failure trial substudy. | Sudden cardiac death remains a leading cause of mortality despite advances in medical treatment for the prevention of ischemic heart disease and heart failure. Recent studies showed a benefit of implantable cardioverter defibrillator implantation, but appropriate shocks for ventricular tachyarrhythmias were noted only in a minority of patients during 4 to 5 years of follow-up. Accordingly, better risk stratification is needed to optimize patient selection. In this regard, microvolt T-wave alternans (TWA) has emerged as a potentially useful measure of arrhythmia vulnerability, but it has not been evaluated previously in a prospective, randomized trial of implantable cardioverter defibrillator therapy.</AbstractText>This investigation was a prospective substudy of the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT) that included 490 patients at 37 clinical sites. TWA tests were classified by blinded readers as positive (37%), negative (22%), or indeterminate (41%) by standard criteria. The composite primary end point was the first occurrence of any of the following events: sudden cardiac death, sustained ventricular tachycardia/fibrillation, or appropriate implantable cardioverter defibrillator discharge. During a median follow-up of 30 months, no significant differences in event rates were found between TWA-positive or -negative patients (hazard ratio 1.24, 95% confidence interval 0.60 to 2.59, P=0.56) or TWA-negative and nonnegative (positive and indeterminate) subjects (hazard ratio 1.28, 95% confidence interval 0.65 to 2.53, P=0.46). Similar results were obtained with the inclusion or exclusion of patients randomized to amiodarone in the analyses.</AbstractText>TWA testing did not predict arrhythmic events or mortality in SCD-HeFT, although a small reduction in events (20% to 25%) among TWA-negative patients cannot be excluded given the sample size of this study. Accordingly, these results suggest that TWA is not useful as an aid in clinical decision making on implantable cardioverter defibrillator therapy among patients with heart failure and left ventricular systolic dysfunction.</AbstractText> |
7,247 | High-throughput analysis of drug binding interactions for the human cardiac channel, Kv1.5. | The voltage-gated potassium channel Kv1.5 is one of the key regulators of membrane potential repolarization in human atrial myocytes and is considered a potential drug target to treat atrial fibrillation. In this study we sought to determine molecular mechanism of action of DPO-1, a diphenylphosphine oxide derivative recently shown to terminate experimental atrial arrhythmia without affecting ventricular refractory period. In addition, we provided similar analysis for additional two small molecule blockers, representing different structural classes: cyclohexanones (PAC) and nor-triterpenoids (correolide). To rapidly identify the residues within the Kv1.5 channel critical for blocking activity of these molecules, two functional high-throughput ion channel assays were employed together with site-directed mutagenesis. Our study revealed that the residues critical for blocking activity of for DPO-1 include T480, localized at the outer mouth of the pore, and two residues along S6 helix: V505 and I508. The overlapping site was identified for PAC and included residues T480 and V505. In contrast to DPO-1, the I508A mutation resulted in only a modest reduction in the block of Kv1.5 by PAC (9-fold). Correolide, the largest molecule examined, made widespread interactions along the entire length of the pore (from T480 to V516). In summary, we have identified multiple residues involved in forming high affinity binding site for Kv1.5 blockers. Similar approaches of high-throughput ion channel technologies, combined with site-directed mutagenesis, may allow for parallel, rapid and accurate analysis of ion channel interactions with multiple compounds and could facilitate the design of more potent and selective ion channel blockers. |
7,248 | The central nervous system cytokine response to global ischemia following resuscitation from ventricular fibrillation in a porcine model. | Pro-inflammatory cytokines have been implicated as culprits in neurotoxicity following ischemia in small animal models of stroke. The aim of this study was to measure the central nervous system (CNS) cytokine response following resuscitation from ventricular fibrillation (VF) in a porcine model of cardiac arrest and global hypoxic ischemia.</AbstractText>VF was induced electrically in 11 anesthetized swine. Following 7 min of untreated VF, animals were resuscitated. Cerebrospinal fluid (CSF) and serum was sampled prior to VF and at 60, 120, and 180 min post-resuscitation from which levels of TNF-alpha, IL-1 beta, and IL-6 were measured. Levels were also drawn in three sham pigs, instrumented but not fibrillated.</AbstractText>CSF levels of TNF-alpha rose following resuscitation and were associated with CSF levels of IL-1 beta (p=0.0002). CSF levels of all cytokines except TNF-alpha were associated with their serum counterparts.</AbstractText>Measurable increases in pro-inflammatory cytokines in the CSF follow resuscitation from cardiac arrest in this porcine model. The CNS response TNF-alpha and IL-1 beta are associated. However, serum levels of TNF-alpha did not seem to predict CSF levels in this study, consistent with the concept of immune privilege of the CNS.</AbstractText> |
7,249 | Predictive power of serum NSE and OHCA score regarding 6-month neurologic outcome after out-of-hospital ventricular fibrillation and therapeutic hypothermia. | To determine the predictive power of the out-of-hospital cardiac arrest (OHCA) score and serum neuron-specific enolase (NSE) in patients resuscitated from ventricular fibrillation treated with therapeutic hypothermia (TH) and glucose control.</AbstractText>An analysis of prospectively collected data of 90 TH patients. Serum NSE was measured at 24 and 48 h. Outcome was measured by neurologic exam 6 months after cardiac arrest with good outcome defined as a Cerebral Performance Category (CPC) of 1 or 2.</AbstractText>In multiple logistic regression analysis, age (odds ratio [OR], 95% confidence interval 1.1 [1.03-1.18]/year), NSE at 48 h (OR 1.1 [1.02-1.26]/microg/l), and increase in NSE levels (OR 7.2 [1.7-31.3]) were predictors of poor outcome, but the OHCA score was not. Cut-off points with 100% specificity in predicting poor outcome were 33microg/l for NSE at 48h (sensitivity 43% [28-60%]) and 6.4microg/l for delta NSE 24-48 h (sensitivity 44% [28-60%]).</AbstractText>Increase in NSE between 24 and 48h and NSE at 48h is specific but only moderately sensitive markers of 6-month outcome. Outcome prediction at ICU admission using the OHCA score was not possible in this selected patient population.</AbstractText> |
7,250 | Improving countershock success prediction during cardiopulmonary resuscitation using ventricular fibrillation features from higher ECG frequency bands. | Countershock outcome prediction using ventricular fibrillation (VF) feature analysis needs undisturbed electrocardiogram (ECG) signals and therefore requires interruption of cardiopulmonary resuscitation (CPR). Features that originate from higher frequency bands of the VF power spectrum may be less affected by CPR artefacts and as such reduce cumulative hands-off intervals.</AbstractText>From 192 patients with in-hospital and out-of-hospital cardiac arrest, four countershock outcome prediction features (peak-peak amplitude, mean slope, median slope, power spectrum analysis) were analysed in 550 short time ECG records, each including a CPR corrupted and a subsequent undisturbed sequence. ECG features calculated from the main frequency band (0-26Hz) and from bandpass-filtered subbands (>10-26Hz) were compared using the similarity level method and differences in shock advice numbers.</AbstractText>The feature similarity between ECG periods with and without CPR artefacts was higher in bandpass-filtered (Sim=0.79, 0.8, 0.78, 0.66) than in unfiltered ECG traces (Sim=0.58, 0.69, 0.68, 0.47). For the features evaluated, the difference in number of shock advices between subsequent traces with and without CPR artefact was significantly reduced using VF analysis from higher frequency bands.</AbstractText>The accuracy of shock outcome prediction during CPR could be increased by using filtered ECG features from higher ECG subbands instead of features derived from the main ECG spectrum.</AbstractText> |
7,251 | Clinical outcome of patients with heart failure and preserved left ventricular function. | Patients with heart failure have a poor prognosis. However, it has been presumed that patients with heart failure and preserved left ventricular function (LVF) may have a more benign prognosis.</AbstractText>We evaluated the clinical outcome of patients with heart failure and preserved LVF compared with patients with reduced function and the factors affecting prognosis.</AbstractText>We prospectively evaluated 289 consecutive patients hospitalized with a definite clinical diagnosis of heart failure based on typical symptoms and signs. They were divided into 2 subsets based on echocardiographic LVF. Patients were followed clinically for a period of 1 year.</AbstractText>Echocardiography showed that more than one third (36%) of the patients had preserved systolic LVF. These patients were more likely to be older and female and have less ischemic heart disease. The survival at 1 year in this group was poor and not significantly different from patients with reduced LVF (75% vs 71%, respectively). The adjusted survival by Cox regression analysis was not significantly different (P=.25). However, patients with preserved LVF had fewer rehospitalizations for heart failure (25% vs 35%, P<.05). Predictors of mortality in the whole group by multivariate analysis were age, diabetes, chronic renal failure, atrial fibrillation, residence in a nursing home, and serum sodium < or = 135 mEq/L.</AbstractText>The prognosis of patients with clinical heart failure with or without preserved LVF is poor. Better treatment modalities are needed in both subsets.</AbstractText> |
7,252 | Ibutilide therapy for atrial fibrillation: 5-year experience in a community hospital. | Many institutions restrict the use of ibutilide because of the potential risk of polymorphic ventricular tachycardia (PMVT). Over a 5-year period from June 2000 to May 2005, 238 patients, 151 men and 87 women, with a mean age of 67.1 years (range, 22-94 years), received intravenous ibutilide at our institution. Ibutilide was administered by nurses or physicians in 4 clinical settings: emergency department (n = 80), intensive care unit (n = 11), patient room on telemetry (n = 107), and in the cardiac catheterization/electrophysiology laboratory (n = 40). Conversion to sinus rhythm occurred in 59% of patients outside the catheterization/electrophysiology laboratory. The incidence of PMVT was 1.7%. Three patients had brief nonsustained PMVT and 1 patient had a sustained PMVT. There was no difference in outcome whether a physician was present at the time of ibutilide administration. Our data suggest that ibutilide is a safe and efficacious drug when ordered by experienced physicians in properly selected patients in a variety of monitored settings. |
7,253 | Relationship between New York Heart Association class change and ventricular tachyarrhythmia occurrence in patients treated with cardiac resynchronization plus defibrillator. | In patients with advanced heart failure (HF) and prolonged QRS interval, cardiac resynchronization therapy (CRT) reduces symptoms and risk of death. The added benefit of an implantable cardioverter defibrillator (ICD) remains questionable in some patients.</AbstractText>In 332 HF patients treated with CRT-D (CRT with ICD) [65 +/- 10 years, 86% men, 23% New York Heart Association (NYHA) class II, 65% class III, and 11% class IV, 70% primary prevention, 55% ischaemic cardiomyopathy, left ventricular ejection fraction 25 +/- 7.5%, and QRS width 167 +/- 32 ms], we evaluated the relationship between functional status change, death at 6-month follow-up (FU), and the occurrence of ventricular tachyarrhythmia/ventricular fibrillation (VT/VF). A total of 68 patients (20.5%) experienced 1266 spontaneous episodes of VT/VF during FU. There was no difference in baseline characteristics between patients with or without VT/VF, except for ICD indication (primary or secondary prevention). Improvement in NYHA class was significantly associated with a decreased occurrence of VT/VF (P = 0.004). Sixteen patients who died had significantly more often VT/VF than the survivors (50 vs. 19%, P = 0.007).</AbstractText>Within the initial 6-month post-CRT therapy, 20% of patients received an appropriate ICD therapy. Patients improving on NYHA class (responders to CRT) have less VT/VF episodes than non-responders. Discriminant criteria for CRT response are awaited to optimize the choice of the device (CRT alone, defibrillator alone, or CRT-D).</AbstractText> |
7,254 | Analysis of atrial fibrillation: from electrocardiogram signal processing to clinical management. | The analysis of atrial fibrillation in non-invasive ECG recordings has received considerable attention in recent years, spurring the development of signal processing techniques for more advanced characterization of the atrial waveforms than previously available. The present paper gives an overview of different approaches to the extraction of atrial activity in the ECG and to the characterization of the resulting atrial signal with respect to its spectral properties. So far, the repetition rate of the atrial waves is the most studied parameter and its significance in clinical management is briefly considered, including the identification of pathomechanisms and prediction of therapy efficacy. |
7,255 | Rhythmic abdominal compression CPR ventilates without supplemental breaths and provides effective blood circulation. | Standard chest-compression CPR has an out-of-hospital resuscitation rate of less than 10% and can result in rib fractures or mouth-to-mouth transfer of infection. Recently, we introduced a new CPR method that utilizes only rhythmic abdominal compressions (OAC-CPR). The present study compares ventilation and hemodynamics produced by chest and abdominal compression CPR.</AbstractText>Twelve swine (29-34kg) were anesthetized, intubated and allowed to breathe spontaneously. Physiologic dead space, resting tidal volume, compression-induced lung air flow, and blood pressures were recorded. Ventricular fibrillation (VF) was electrically induced and subjects were treated with either standard CPR or OAC-CPR at various force and rate settings. Minute alveolar ventilation (MAV) and mean coronary perfusion pressure (CPP) were compared.</AbstractText>For OAC-CPR, ventilation per compression tended to increase with increasing force and decreasing rate. Chest only compressions produced no MAV, while OAC-CPR at 80cycles/min or less, matched the MAV for spontaneous respiration. For all rates, abdominal compressions met, or exceeded, the CPP of chest compressions performed at 100lbs.</AbstractText>OAC-CPR generated ventilatory volumes significantly greater than the dead space and produced equivalent, or larger, CPP than with chest compressions. Thus, OAC-CPR ventilates a subject, eliminating the need for mouth-to-mouth breathing, and effectively circulates blood during VF without breaking ribs. Furthermore, this technique is simple to perform, can be administered by a single rescuer, and should reduce bystander reluctance to administer CPR.</AbstractText> |
7,256 | Vigilance, awareness and a phone line: 20 years of expediting CPR for enhancing survival after out-of-hospital cardiac arrest. The 'SHL'-Telemedicine experience in Israel. | The only large-scale report (1988) by the Israeli national ambulance service Magen David Adom (MDA) on the outcome of cardiac arrest victims who underwent cardiopulmonary resuscitation (CPR) by paramedics called for more frequent and more promptly initiated CPR and shorter time to arrival of paramedic care to improve survival. We report the 1987-2007 experience of resuscitation of out-of-hospital cardiac arrest victims who were 'SHL'-Telemedicine subscribers and who underwent CPR by SHL-Telemedicine mobile intensive care units (MICUs) personnel or under their instructions.</AbstractText>'SHL's records of MICU reports and specifics of CPR maneuvers and outcome of resuscitated patients, as recorded by its MICU physicians, were analyzed to determine whether the system enhanced survival.</AbstractText>A total of 1810 'SHL'-Telemedicine subscribers (mean age 76+/-12 years [16-104], 67% males) were resuscitated after cardiac arrest, 597 (33%) were hospitalized and 279 (15.4%) were discharged alive. Factors associated with successful resuscitation included witnessed collapse and documented ventricular fibrillation upon MICU arrival. A history of diabetes, hyperlipidemia, stroke or advanced age adversely affected the outcome. Time from collapse to CPR initiation and duration of CPR correlated significantly with survival. Laymen instructed telephonically by the 'SHL'-Telemedicine center performed CPR on 121 patients: 13 (10%) survived to hospital discharge.</AbstractText>'SHL'-Telemedicine's policy of bi-monthly contact with its subscribers led to heightened awareness of warning signs and need for rapid summoning of medical assistance in the setting of out-of-hospital sudden cardiac arrest.</AbstractText> |
7,257 | Blood pressure and heart rate immediately after termination of short-term ventricular fibrillation. | Implantable cardioverter/defibrillators (ICDs) can detect ventricular fibrillation (VF) and terminate it. For determining the optimal defibrillation threshold, ventricular fibrillation is repetitively induced and terminated with DC shocks. Depending on the protocol, several fibrillation/defibrillation sequences are mandatory before the final implantation of an ICD. This procedure provides an elegant human model of circulatory arrest and resuscitation.</AbstractText>In anesthetized 73 patients (15 females) of on the average 60+/-11 years, the end-expiratory pressure was set to zero. Left ventricular pressure (LVP) was monitored with a microtip-catheter, central venous pressure (CVP) through a cannula which was advanced into the superior V. cava. ECG was recorded. After testing, a monoexponential function was found to best fit the time courses of LVP, CVP and heart rate. Data are mean+/-S.D.</AbstractText>After termination of circulatory arrest, peak LVP increased with a time constant tau of 9.2+/-4.2 beats, CVP decreased with tau=2.8+/-1.5 beats, and RR-intervals decreased with tau=4.3+/-3.5 beats. Correlations between prefibrillatory values and steady-state values after termination of fibrillation were high: peak LVP: r=0.78; CVP: r=0.95; RRI: r=0.82.</AbstractText>After DC termination of VF, the heart 'finds' relatively quickly a steady-state rhythm at the prefibrillatory level (22 beats), thereby normalizing CVP almost in parallel (14 beats). Peak LVP plateaus only after about 40 beats, although reasonable arterial pressures are reached within the first beats. Our data are limited to periods of ventricular fibrillation of no longer than 60s, which limits the generalisability to the setting of clinical cardiac arrest.</AbstractText> |
7,258 | Precordial thump efficacy in termination of induced ventricular arrhythmias. | Reports about the efficacy of precordial thump (PT) in the termination of ventricular arrhythmias (VA) vary widely. Very little recent data about the mechanical termination of VA induced during programmed ventricular stimulation are available.</AbstractText>We prospectively studied 485 consecutive patients (May 2001 to December 2007) who underwent electrophysiology study with programmed ventricular stimulation as part of their assessment for primary or secondary prevention of sudden cardiac death. In cases of induction of sustained non-tolerated VA, one of two experienced cardiologists applied a precordial thump for termination of these arrhythmias immediately after the onset of unconsciousness. When PT was ineffective, the arrhythmia was terminated by electrical cardioversion. Tolerated VA was terminated by antitachycardic pacing.</AbstractText>Sustained VA was induced in 237 patients. In 82 patients with tolerated VA, overdriving was used successfully. Sustained induced VA was not tolerated in 155 patients (mean age 64 years (32-82), 133 males and 22 females, 126 patients with coronary artery disease, left ventricular ejection fraction 30+/-11%). Mean RR interval of induced VA was 226+/-47ms. Mean time to termination of arrhythmia (by PT or DC shock) was 26s (12-280s). PT terminated VA (polymorphic ventricular tachycardia) in only two patients; in 153 patients (98.7%), PT was ineffective. We did not observe any complication of PT application.</AbstractText>Efficacy of PT in termination of induced non-tolerated VA is very low even with early application after VA onset.</AbstractText> |
7,259 | Effects of pre-arrest and intra-arrest hypothermia on ventricular fibrillation and resuscitation. | Hypothermia has been shown to improve survival and neurological outcomes for ventricular fibrillation (VF) cardiac arrest. The electrophysiological mechanisms of hypothermia are not well-understood, nor are the effects of beginning cooling during the resuscitation.</AbstractText>We hypothesized that inducing hypothermia prior to the onset of VF would slow the deleterious changes seen in the ECG during VF and that inducing hypothermia at the start of resuscitation would increase the rates of ROSC and short-term survival in a porcine model of prolonged VF. We randomly assigned 42 domestic swine (27.2+/-2.3 kg) to either pretreatment with hypothermia before induction of VF (PRE), normothermic resuscitation (NORM) or intra-resuscitation hypothermia (IRH). During anesthesia, animals were instrumented via femoral cutdown. Lead II ECG was recorded continuously. PRE animals were cooled before the induction of VF, with a rapid infusion of 4 degrees normal saline (30mL/kg). VF was induced electrically, left untreated for 8min, then mechanical CPR began. During CPR the NORM animals got 30mL/kg body-temperature saline and the IRH animals got 30mL/kg 4 degrees saline. In all groups first rescue shocks were delivered after 13min of VF. We calculated the VF scaling exponent (ScE) for the entire 8min period (compared using GEE). ROSC and survival were compared with Fisher's exact test. Mean temperature in degrees C at the onset of VF was PRE=34.7 degrees (+/-0.8), NORM=37.8 (+/-0.9), and IRH=37.9 (+/-0.9). The ScE values over time were significantly lower after 8min in the PRE group (p=0.02). ROSC: PRE=10/14 (71%), NORM=6/14 (43%) and IRH=12/14 (86%); p for IRH vs. NORM=0.02. Survival: PRE=9/14 (64%), NORM=5/14 (36%), IRH 8/14 (57%).</AbstractText>Hypothermia slowed the decay of the ECG waveform during prolonged VF. IRH improved ROSC but not short-term survival compared to NORM. It is possible to rapidly induce mild hypothermia during CPR using an IV infusion of ice-cold saline.</AbstractText> |
7,260 | Spontaneous gasping increases cerebral blood flow during untreated fatal hemorrhagic shock. | Gasping has been found to be associated with improved ventilation, stroke volume, and cerebral blood flow (CBF) during untreated ventricular fibrillation. However, its effects have not been thoroughly assessed during fatal hemorrhagic shock. In this study, we hypothesized that gasping increases CBF during fatal hemorrhagic shock.</AbstractText>Ten male Wistar rats (body weight: 195-225g) were intraperitoneally anesthetized with sodium pentobarbital (50mg/kg). Arterial pressure was recorded in the left femoral artery. Respiratory thoracic movements were recorded with a pressure sensor placed under the animal's back. The left carotid artery was cannulated to continuously withdraw blood (0.1ml/min) as a means of inducing hemorrhagic shock. CBF was measured with a laser flow meter.</AbstractText>The arterial pulse wave was lost after withdrawing 7.3+/-0.9ml of blood and at that point, spontaneous gasping developed in all of the animals. CBF averaged 48.8+/-8.8ml/(min100g-brain) under control conditions before the start of blood withdrawal, and it decreased significantly to 4.4% of baseline during the pulseless state (P<0.01). The gasping, observed during in the pulseless state increased CBF to an average of 54.2% of baseline (P<0.01).</AbstractText>Gasping was observed during fatal hemorrhagic shock and generated large increases in CBF. The forceful contraction of the inspiratory muscles during gasping may increase CBF by decreasing intrathoracic pressure, which increases venous return to the heart.</AbstractText> |
7,261 | Cardiac catheterization is underutilized after in-hospital cardiac arrest. | Indications for immediate cardiac catheterization in cardiac arrest survivors without ST elevation myocardial infarction (STEMI) are uncertain as electrocardiographic and clinical criteria may be challenging to interpret in this population. We sought to evaluate rates of early catheterization after in-hospital ventricular fibrillation (VF) arrest and the association with survival.</AbstractText>Using a billing database we retrospectively identified cases with an ICD-9 code of cardiac arrest (427.5) or VF (427.41). Discharge summaries were reviewed to identify in-hospital VF arrests. Rates of catheterization on the day of arrest were determined by identifying billing charges. Unadjusted analyses were performed using Chi-square, and adjusted analyses were performed using logistic regression.</AbstractText>One hundred and ten in-hospital VF arrest survivors were included in the analysis. Cardiac catheterization was performed immediately or within 1 day of arrest in 27% (30/110) of patients and of these patients, 57% (17/30) successfully received percutaneous coronary intervention. Of those who received cardiac catheterization the indication for the procedure was STEMI or new left bundle branch block (LBBB) in 43% (13/30). Therefore, in the absence of standard ECG data suggesting acute myocardial infarction, 57% (17/30) received angiography. Patients receiving cardiac catheterization were more likely to survive than those who did not receive catheterization (80% vs. 54%, p<.05).</AbstractText>In patients receiving cardiac catheterization, more than half received this procedure for indications other than STEMI or new LBBB. Cardiac catheterization was associated with improved survival. Future recommendations need to be established to guide clinicians on which arrest survivors might benefit from immediate catheterization.</AbstractText> |
7,262 | Effect of cooling after human cardiac arrest on myocardial infarct size. | The Hypothermia after Cardiac Arrest (HACA) trial assessed whether mild therapeutic hypothermia improved the rate of good neurological recovery in patients after ventricular fibrillation cardiac arrest of presumed cardiac origin. We evaluated the impact of hypothermia on myocardial injury.</AbstractText>Re-analysis of a HACA trial subset for our department (cooling, n=55; controls, n=56). Plasma levels of CK, CKMB and ST-scores were used as a measure of infarct size.</AbstractText>Area under the curve (AUC) for CK was 28,786U/l x 24 h (IQR 5646-44,998) in the cooling group and 20,373U/l x 24 h (IQR 8211-30,801) for controls (p=0.40), for CKMB AUC was 1691U/l x 24 h (IQR 724-3330) and 1187U/l x 24 h (IQR 490-2469), respectively (p=0.18). The ST score was -40% (IQR [-55]-[+16]) in the cooling group (n=23) and -22% (IQR [-84]-[+33]) for controls (n=24) (p=0.76). When the cooling group was stratified into early (< or =8h) and longer (>8h) time to target temperature, the early group displayed a significantly lower CK 7340U/l x 24 h (IQR 3921-33,753) vs. 38,986U/l x 24 h (IQR 23,945-57,514, p=0.007) and a lower CKMB.</AbstractText>Cooling after successful resuscitation for ventricular fibrillation cardiac arrest did not influence infarct size. Cautious interpretation of the subgroup analysis may indicate a favourable trend for early cooling.</AbstractText> |
7,263 | Benchmarking ventricular arrhythmias in the mouse--revisiting the 'Lambeth Conventions' 20 years on. | The isolated Langendorff-mode perfused heart has become a valuable experimental model, used extensively to examine cardiac function, pathophysiology and pharmacology. For the clinical cardiologist an ECG is often a simple practicality, however in experimental circumstances, particularly with ex vivo murine hearts it is not always possible to obtain an ECG due to experimental recording constraints. However, the mechanical record of ventricular contractile function can be highly informative in relation to electrical state. It is difficult though to achieve consistency in these evaluations of arrhythmia as a validated common reference framework is lacking. In 1988, a group of investigators developed the 'Lambeth Conventions'--a standardised reference for the definition and classification of arrhythmias in animal experimental models of ischaemia, infarction and reperfusion in vivo. Now, two decades later it is timely to revisit the Lambeth Conventions, and to update the guidelines in the context of the marked increase in murine heart study in experimental cardiac pathophysiology. Here we describe an adjunct to the Lambeth Conventions for the reporting of ventricular arrhythmias post-ischaemia in ex vivo mouse hearts when ECG recordings are not employed. Of seven discrete and identifiable patterns of mechanical dysrhythmia observed in reperfusion, five could be classified using conventional ECG terminology: ventricular premature beat, bigeminy, trigeminy, ventricular tachycardia and ventricular fibrillation. Two additional rhythm variations detected from the pressure record are described (potentiated contraction and alternans). |
7,264 | A randomized trial of the effect of automated ventricular capture on device longevity and threshold measurement in pacemaker patients. | An automatic capture (AC) algorithm adjusts ventricular pacing output to capture the ventricle while optimizing output to 0.5 V above threshold. AC maintains this output and confirms capture on a beat-to-beat basis in bipolar and unipolar pacing and sensing.</AbstractText>To assess the AC algorithm and its impact on device longevity.</AbstractText>Patients implanted with a pacemaker were randomized 1:1 to have the AC feature on or off for 12 months. Two threshold tests were conducted at each visit- automatic threshold and manual threshold. Average ventricular voltage output and projected device longevity were compared between AC on and off using nonparametric tests.</AbstractText>Nine hundred ten patients were enrolled and underwent device implantation. Average ventricular voltage output was 1.6 V for the AC on arm (n = 444) and 3.1 V for the AC off arm (n = 446) (P < 0.001). Projected device longevity was 10.3 years for AC on and 8.9 years for AC off (P < 0.0001), or a 16% increase in longevity for AC on. The proportion of patients in whom there was a difference between automatic threshold and manual threshold of <or=0.5 V through follow-up was 99.0% (95% CI: 98.6, 99.3). The average difference between automatic threshold and manual threshold was 0.07 V (P = 0.002).</AbstractText>This study showed that automatic threshold testing at follow-up provided comparable information to manually measured threshold testing. AC provided a significant increase in projected device longevity compared to standard programing.</AbstractText> |
7,265 | Nonischemic dilated cardiomyopathy: results of noninvasive and invasive evaluation in 310 patients and clinical significance of bundle branch block. | The survival of patients with idiopathic dilated cardiomyopathy (IDCM) at III and IV stages of New York Heart Association (NYHA) is decreased in those with a bundle branch block (BBB) compared to those without BBB. Less is known on the prognosis of patients at earlier stages of NYHA and who had a left BBB (LBBB) or right BBB (RBBB). We sought to evaluate the prevalence and the clinical significance of LBBB or RBBB in patients with IDCM and classes I and II of NYHA.</AbstractText>Clinical data, noninvasive, and invasive studies were consecutively collected in 310 patients, with IDCM, followed up to 4.8+/-3.7 years.</AbstractText>Seventy-six patients (25%) had LBBB, 21 (7%) had RBBB, and 212 had no BBB. Patients with BBB were older than other patients (P < 0.009). Left ventricular ejection fraction (LVEF) was lower in LBBB than in RBBB and other patients (P < 0.05). Syncope was more frequent in BBB than in absence (P < 0.05). Incidence of spontaneous ventricular tachycardia (VT) and atrial fibrillation, VT induction, total cardiac events, and sudden death were similar in the presence or absence of BBB. Deaths by heart failure and heart transplantations tended to be more frequent in BBB than in absence.</AbstractText>LBBB was present in 25% of patients with IDCM; RBBB was rare. Patients with BBB were older and had more frequent syncope than patients without BBB; LVEF was lower in LBBB than in RBBB or in absence of BBB. BBB did not increase the risk of spontaneous VT, VT induction, or sudden death, and tended to increase deaths by heart failure and the indications of heart transplantation.</AbstractText> |
7,266 | Insulin sensitivity measured by the euglycaemic insulin clamp and proinsulin levels as predictors of stroke in elderly men. | <AbstractText Label="AIMS/HYPOTHESIS" NlmCategory="OBJECTIVE">Our aim was to investigate the predictive power of a panel of variables in glucose and insulin metabolism for the incidence of stroke or transient ischaemic attacks (TIA). We hypothesised that proinsulin and insulin resistance contributes to an increase of risk for fatal and non-fatal stroke/TIA, independently of diabetes and established risk factors.</AbstractText>The study is based on the Uppsala Longitudinal Study of Adult Men cohort. The examinations were performed at age 70 years.</AbstractText>In 1,151 men free from stroke at baseline, 150 developed stroke or TIA during a median follow-up of 8.8 years. In unadjusted Cox proportional hazards analyses, a 1 SD increase of a predictor variable was associated with an increased risk for stroke/TIA, e.g. plasma insulin (HR 1.19, 95% CI 1.01-1.40), fasting intact proinsulin (HR 1.28, 95% CI 1.09-1.49); whereas a 1 SD increase in insulin sensitivity measured by the euglycaemic insulin clamp method decreased the risk for stroke/TIA (HR 0.81, 95% CI 0.68-0.96). The predictive values of fasting intact proinsulin and insulin sensitivity endured but not that of plasma insulin when adjusting for diabetes. In models adjusting for diabetes, hypertension, atrial fibrillation, electrocardiographic left ventricular hypertrophy, serum cholesterol and smoking, proinsulin remained as a significant predictor of later stroke/TIA (HR 1.22, 95% CI 1.00-1.48) whereas clamp insulin sensitivity did not (HR 0.87, 95% CI 0.71-1.07).</AbstractText><AbstractText Label="CONCLUSIONS/INTERPRETATION" NlmCategory="CONCLUSIONS">Fasting intact proinsulin level and insulin sensitivity at clamp predicted subsequent fatal and non-fatal stroke/TIA, independently of diabetes in elderly men whereas fasting insulin did not.</AbstractText> |
7,267 | Early results of off-pump coronary artery bypass graft surgery using bilateral internal thoracic artery grafts in octogenarian patients during ten years. | The aim of this study is to review the outcome of OP-CABG using bilateral internal thoracic artery (BITA) grafts in these patients in terms of morbidity and mortality.</AbstractText>Retrospective data from consecutive 64 octogenarian patients who underwent this surgery in the period between April 1998 and December 2007 were taken. Demographic data, risk factors, and details of surgical intervention and postoperative complications were analysed.</AbstractText>The mean age was 81.8+/-1.8 years (males=78.1%). Expected mortality calculated by additive EuroSCORE was 7.1+/-1.9%. The mean of left ventricular ejection fraction was 57.3+/-12.3%. Unstable angina was the main presenting symptom in 70.3% of patients and 18.7% had recent acute myocardial infarction. Hospital morbidity and mortality rates were 60.9 and 6.2%, respectively. The most frequent complications were: respiratory (25%) and atrial fibrillation (17.2%). The means of stay in intensive care unit and total hospital stay were 2.4+/-1.9 and 7.6+/-3.7 days, respectively.</AbstractText>Realizing OP-CABG using BITA grafts had a high rate of postoperative morbidity, however, the mortality rate was low.</AbstractText> |
7,268 | Diagnosis and treatment of pulmonary arterial hypertension and atrial fibrillation in an adult chimpanzee (Pan troglodytes). | This report describes the diagnosis and treatment of pulmonary arterial hypertension (PAH) in an adult male captive chimpanzee. Although cardiovascular disease in general is common in human and great apes, diagnosis and treatment of PAH in nonhuman primates are uncommon. In the case we present, the adult chimpanzee was diagnosed with an arrhythmia during an annual physical examination and later with PAH during a scheduled cardiovascular evaluation. PAH can either be primary or secondary and can lead to right ventricular overload and heart failure. This description is the first case study of pulmonary arterial hypertension in a great ape species. |
7,269 | The heme oxygenase inducer hemin protects against cardiac dysfunction and ventricular fibrillation in ischaemic/reperfused rat hearts: role of connexin 43. | Cardiac expression of cytoprotective gene heme oxygenase-1 (HO-1) is modulated by ischaemia and reperfusion (I/R). We therefore hypothesized that pretreatment with hemin, an inductor of HO-1, would precondition the heart against post-ischaemic dysfunction and ventricular fibrillation (VF). Male Wistar rats were given either hemin or HO enzyme inhibitor zinc protoporphyrin IX (ZnPP IX). Isolated hearts were subjected to 30 min global ischaemia followed by 120 min of reperfusion or were aerobically perfused in a time-matched non-ischaemic protocol. Control animals received no pretreatment. Compared to non-perfused controls, pretreatment with hemin increased HO-1 mRNA 13-fold (p<0.001) and HO-1 protein 3.5-fold (p<or=0.001), improved post-ischaemic aortic flow, coronary flow, LVDP and -Dp/dt (p<0.01) and decreased LVEDP (p<0.001) and the incidence of VF (p = 0.001). The improved post-ischaemic cardiac function and reduction of VF were accompanied by a higher total connexin 43 (Cx43) level compared to non-pretreated and ZnPP IX pretreated hearts, and accumulation of non-phosphorylated gap junction protein Cx43 in intercalated discs and lateral plasma membrane of cardiomyocytes. Cardioprotection by HO-1 appeared to be independent of cGMP. Administration of ZnPP IX had no effect on cardiac function or VF. Our results show that pharmacological modulation of HO-1 pathway may provide a new therapeutic approach to protect the heart against post-ischaemic dysfunction and I/R-induced VF possibly by a Cx43 dependent mechanism. |
7,270 | Adaptive singular value cancelation of ventricular activity in single-lead atrial fibrillation electrocardiograms. | The proper analysis and characterization of atrial fibrillation (AF) from surface electrocardiographic (ECG) recordings requires to cancel out the ventricular activity (VA), which is composed of the QRS complex and the T wave. Historically, for single-lead ECGs, the averaged beat subtraction (ABS) has been the most widely used technique. However, this method is very sensitive to QRST wave variations and, moreover, high-quality cancelation templates may be difficult to obtain when only short length and single-lead recordings are available. In order to overcome these limitations, a new QRST cancelation method based on adaptive singular value cancelation (ASVC) applied to each single beat is proposed. In addition, an exhaustive study about the optimal set of complexes for better cancelation of every beat is also presented for the first time. The whole study has been carried out with both simulated and real AF signals. For simulated AF, the cancelation performance was evaluated making use of a cross-correlation index and the normalized mean square error (nmse) between the estimated and the original atrial activity (AA). For real AF signals, two additional new parameters were proposed. First, the ventricular residue (VR) index estimated the presence of ventricular activity in the extracted AA. Second, the similarity (S) evaluated how the algorithm preserved the AA segments out of the QRST interval. Results indicated that for simulated AF signals, mean correlation, nmse, VR and S values were 0.945 +/- 0.024, 0.332 +/- 0.073, 1.552 +/- 0.386 and 0.986 +/- 0.012, respectively, for the ASVC method and 0.866 +/- 0.042, 0.424 +/- 0.120, 2.161 +/- 0.564 and 0.922 +/- 0.051 for ABS. In the case of real signals, the mean VR and S values were 1.725 +/- 0.826 and 0.983 +/- 0.038, respectively, for ASVC and 3.159 +/- 1.097 and 0.951 +/- 0.049 for ABS. Thus, ASVC provides a more accurate beat-to-beat ventricular QRST representation than traditional techniques. As a consequence, VA cancelation is optimized and the AA can be extracted more precisely. Finally, the study has proven that optimal VA cancelation is achieved when a number between 20 and 30 complexes is selected following a correlation-based strategy. |
7,271 | Early repolarization phenomenon in arrhythmogenic right ventricular dysplasia-cardiomyopathy and sudden cardiac arrest due to ventricular fibrillation. | The case of a 26-year-old male with sudden cardiac arrest due to ventricular fibrillation and the final diagnosis of arrhythmogenic right ventricular dysplasia-cardiomyopathy (ARVD/C) and initial early repolarization phenomenon is presented in detail. An additional analysis of early repolarization in additional 359 patients with ISFC/ESC diagnostic criteria of ARVD/C revealed a frequency within the threshold in healthy volunteers with 3% in isolated lateral leads and 7% in inferolateral leads. The high frequency of electrocardiographic early repolarization limited to inferior leads (22%) is probably due to late depolarization and represents an already reported typical feature of ARVD/C. |
7,272 | [Acute heart failure and preserved systolic function: can we explain all only by the diastolic dysfunction? A prospective study on 145 patients hospitalized for acute pulmonary edema]. | Heart failure with conserved systolic function is frequent and attributed to the diastolic dysfunction. The diagnosis of diastolic heart failure requires the association of clinical signs of heart failure, a conserved left ventricular systolic function and a diastolic dysfunction.</AbstractText>To determine the proportion of cases of isolated diastolic heart failure among patients hospitalized for acute pulmonary edema.</AbstractText>The left ventricular ejection fraction (LVEF), the diastolic function and levels of NT-proBNP have been assessed at admission of 145 patients hospitalized for acute pulmonary edema.</AbstractText>49% of patients included were older than 80 years (mean age 78.6 + 0.9 years). Among the 83 patients with conserved LVEF, 25% had an ischemic heart disease, 24% a severe valvular disease, 22% an atrial fibrillation, 5% a severe bradycardia, 2% a severe hypertrophic obstructive cardiomyopathy. Only 15 patients presented an isolated diastolic heart failure. The level of NT-proBNP was correlated to LVEF but was not able to identify those with isolated diastolic heart failure in the group with "conserved systolic function".</AbstractText>Among patients hospitalized for acute pulmonary edema, the prevalence of heart failure with conserved systolic function is high, but only 10% of them presented an isolated diastolic heart failure. The NT-proBNP levels do not permit to identify them.</AbstractText> |
7,273 | Management of high defibrillation threshold. | The implantable cardioverter defibrillator (ICD) has become the primary therapy for the treatment of potentially lethal ventricular arrhythmias. Ventricular arrhythmias encompass a spectrum of rhythm disturbances ranging from the occasional monomorphic ventricular premature complex to the almost universally fatal ventricular fibrillation. Our understanding of the mechanisms of ventricular fibrillation and defibrillation is still in evolution. At present, the most common ICD configuration consists of a pectoral pulse generator (active-can) with a bipolar transvenous dual coil lead. A transvenous system with an active-can has improved defibrillation thresholds and the ease of implantation. However, there are various clinical scenarios in which patients with high defibrillation threshold (DFT) are encountered. Although the incidence of high DFT patients is low, it is of significant concern since it may account for sudden cardiac death in patients with ICDs. At present, there are few clinical trials that are rigorous and well designed, and which can define a perfect methodology for the treatment of high DFT patients. In this review, in the context of commonly encountered clinical scenarios, we discuss therapeutic strategies to help manage patients with high DFT. |
7,274 | Hypoglycaemia as a possible cause of transient ischaemic attack in a patient with multiple vascular risk factors. | An elderly, fibrillating, diabetic hypertensive patient in heart failure is at risk of stroke from all her cardiovascular morbidities. When such a patient presents with stroke, it is usually difficult to squarely incriminate one. Consequently, precious time is lost while care givers conduct expensive investigations to make a definitive diagnosis. This case report is on one such patient, in whom hypoglycaemia was a plausible cause. Treatment resulted in dramatic recovery. Had neurological complication of drug induced hypoglycaemia not been suspected, the hemiplegia might have become permanent; and any of her risk factors given as a rational explanation. Therefore when a diabetic on treatment presents with stroke, care givers should perform immediate blood glucose test to exclude hypoglycaemia; not withstanding the existence of other risk factors. |
7,275 | [Ventricular arrhythmias of catecholaminergic origin and sudden death]. | The hereditary disease known as polymorphic catecholaminergic ventricular tachycardia (PCVT) is highly lethal. Almost 30% of the affected patients die before 40 years old, mainly due to sudden cardiac death. We have used isolated hearts from mutant mice (type 2 ryanodine receptors, RyR2/RyR2(R4496C)) to investigate arrhythmia mechanisms that are adrenergic- and intracellular calcium ([Ca2+]o) levels-dependent. Our results corroborate that polymorphic and bidirectional ventricular arrhythmias, as well as ventricular fibrillation, occurs in 50% of RyR2/ RyR2(R4496C) mice, and in less than 12% of the non-affected mice. Our hypothesis suggests that the origin of catecholaminergic arrhythmias in animals, and possibly in humans, is conditioned by the focal activity that begins by late post-potentials in the Purkinje fibers. |
7,276 | [Cardiothyrotoxicosis in the young adult in Marrakech. A report of 36 cases]. | Thyrotoxicosis is underdiagnosed because of its low occurrence in series from Africa. The aim of this study was to evaluate the frequency, the demographic data, and the etiological aspects of thyrotoxicosis among hyperthyroidy. Thirty-six patients with thyrotoxicosis (group I) gathered during a period of four years was analysed, as well as 180 hyperthyroidy cases (group II). Cardiothyrotoxicosis was observed with a frequency of 16.6%. The mean age was respectively of 44.5+/-13.3 versus 32.8+/-11.4 years (p<10(-6)). Cardiothyrotoxicosis was related to multinodular goitres (18 cases), a Basedow disease (14 cases), a toxic adenoma (four cases), while the principal cause of hyperthyroidy was toxic adenoma followed by the Basedow disease (72 cases, 40%). Different modes of presentation of cardiothyrotoxicosis were found: cardiac heart failure in 27 cases (75%), permanent atrial fibrillation in 22 cases (61.1%), atrial flutter in two cases, coronary insufficiency in four cases, ventricular extrasystoli (trigeminism) in two cases, second auriculoventricular block in two cases, dilated myocardiopathy in 10 cases (27.7%), ischemic myocardiopathy in four cases, severe mitral regurgitation in one case. This study confirms the relative frequency of cardiothyrotoxicosis, the proportionally weak place of Basedow disease among hyperthyroidy's causes, and role of associated cardiac disease to the hyperthyroid. |
7,277 | Paroxysmal atrial fibrillation is associated with increased intra-atrial conduction delay. | A novel electrophysiological technique, paced electrogram fractionation analysis (PEFA), which measures activation delay of stimulated beats through the myocardium, has shown that long delays in activation are strongly associated with sudden cardiac death due to ventricular fibrillation. The aim of our study was to determine whether there are differences in intra-atrial conduction in patients with and without paroxysmal atrial fibrillation (PAF) using PEFA. Twenty patients (15 women) in the mean age 54.7 +/- 16.6 years, scheduled for transcatheter ablation of their arrhythmias, were divided into two groups: 10 controls without PAF and 10 patients with PAF.</AbstractText>During PEFA, pacing and recording catheters were placed in the coronary sinus (three sites: distal, mid, and proximal) and at four right atrium sites: crista terminalis (one site), RA isthmus (one site), and interatrial septum (two sites). The PEFA protocol involves pacing from one site and recording electrograms from other six sites. A decremental sequence, delivered at one site, had a cycle length of 490 ms (S1S1) with an extrastimulus inserted every third beat whose coupling interval (S1S2) is reduced by 1 ms on each occasion. This process is repeated from each atrial site. The S1S2 at which electrogram duration starts to prolong, and the increase in electrogram duration is determined at all sites. In three patients from the PAF group, atrial fibrillation was induced during PEFA and it was terminated by electrical cardioversion. No other complications were noted. The patients with PAF, compared with the control group, have abrupt increases in the electrogram duration, which occur, at significantly longer S1S2 (P < 0.0001). There were also significantly longer intra-atrial delays in the intrinsic deflection of the electrogram in PAF patient vs. control group (P < 0.0001).</AbstractText>Comparison of PAF and non-AF patient groups showed that intra-atrial conduction delay start in the PAF group earlier (with longer S1S2 intervals) and they are significantly longer in the PAF group. This suggests that atria in patients with PAF are diffusely diseased and that the measured activation delays form one component of an arrhythmogenic substrate.</AbstractText> |
7,278 | Atrial fibrillation with rapid ventricular response in pregnancy. | To report a case of atrial fibrillation with rapid ventricular response occurring during pregnancy.</AbstractText>A 35-year-old woman, gravida 3, para 1, abortus 1, with a history of persistent supraventricular arrhythmia, presented at 22 weeks' gestation. After adenosine administration, electrocardiography revealed atrial fibrillation with rapid ventricular response. The episode was complicated by hemodynamic instability and was refractory to verapamil. Sinus rhythm was restored after synchronized electrical cardioversion under sedation. Sotalol (80 mg) was given for arrhythmia and to control heart rate. The patient experienced a second episode of supraventricular arrhythmia at 26 weeks' gestation, which was also reversed after cardioversion. She delivered a healthy male baby at 38 weeks' gestation via scheduled cesarean section.</AbstractText>Arrhythmias with underlying heart disease can result in serious hemodynamic deterioration. Electrical cardioversion is well-tolerated and effective in pregnant women and should not be withheld if clinically indicated.</AbstractText> |
7,279 | Outcome of patients with haemodynamically stable ventricular tachycardia treated with an implantable cardioverter-defibrillator. | The benefit of implantable cardioverter defibrillator (ICD) therapy in patients with haemodynamically stable ventricular tachycardia (VT) is not well documented.</AbstractText>In this single-centre observational study, we examined the medical records of 53 patients (48 men, mean age 66 +/- 1 years) treated with an ICD. The patients were classified into four groups with comparable clinical and electrophysiological characteristics, as follows: patients presenting with (a) stable VT, (b) unstable VT, (c) cardiac arrest, and (d) non-sustained VT and induced sustained VT or ventricular fibrillation (VF) on electrophysiological study. Kaplan-Meier event-free survival curves were constructed and the incidence of appropriate device therapy was compared among the four groups.</AbstractText>All patients had structural heart disease with a mean ejection fraction of 32.5 +/- 1.3%. During a mean follow-up period of 35.5 +/- 2.7 months, event-free survival was similar in the four groups. However, appropriate device therapy occurred in 9 (81.8%) patients with stable VT, in 6 (44.4%) patients with unstable VT, in 2 (33.3%) patients with cardiac arrest and in 6 (33.3%) patients with non-sustained VT and induced sustained VT/VF. Compared to the total patient cohort, appropriate therapy was significantly (p = 0.024) more common in patients presenting with stable monomorphic VT. In 2 (22.2%) of these patients, the tachycardia rate was faster than the presenting VT.</AbstractText>High recurrence rates are observed in patients with structural heart disease and stable VT, with a considerable proportion being faster than the presenting VT. ICD therapy is beneficial and should be offered in these patients.</AbstractText> |
7,280 | Heart rhythm and cardiac pacing: an integrated dual-chamber heart and pacer model. | Modern cardiac pacemaker can sense electrical activity in both atrium and ventricle, and deliver precisely timed stimulations to one or both chambers on demand. However, little is known about how the external cardiac pacing interacts with the heart's intrinsic activity. In this study, we present an integrated dual-chamber heart and pacer (IDHP) model to simulate atrial and ventricular rhythms in the presence of dual chamber cardiac pacing and sensing. The IDHP model is an extension and improvement of a previously developed open source model for simulating ventricular rhythms in atrial fibrillation and ventricular pacing. The new model takes into account more realistic properties of atrial and ventricular rhythm generators, as well as bi-directional conductions in atrium, ventricle, and the atrio-ventricular junction. Moreover, an industry-standard dual-chamber pacemaker timing control logic is incorporated in the model. We present examples to show that the new model can generate realistic cardiac rhythms in both physiologic and pathologic conditions, and simulate various interactions between intrinsic heart activity and extrinsic cardiac pacing. Among many applications, the IDHP model provides a new simulation platform where it is possible to bench test advanced pacemaker algorithms in the presence of different types of cardiac rhythms. |
7,281 | Rhabdomyolysis after liver transplantation: a case report. | Our aim was to present the case of a pediatric biliary atresia patient who experienced rhabdomyolysis with severe cardiac arrhythmias associated with hyperkalemia, metabolic acidosis, and myoglobulinemia during liver transplantation. A 5-year-old girl, weighing 16.5 kg, with end-stage liver disease due to biliary atresia underwent living donor liver transplantation. A sudden onset of atrial fibrillation with rapid ventricular response was noted during the transplantation. The cardiac arrhythmia was associated with hyperkalemia, metabolic acidosis, and myoglobulinemia. Rhabdomyolysis was suspected. Hyperkalemia and metabolic acidosis were not corrected despite treatment with 10 mL of 50% glucose plus 6 U of regular insulin in 4 succeeding boluses and 110 mEq sodium bicarbonate before sending the patient to the intensive care unit. A corresponding decrease and normalization in serum potassium and correction of metabolic acidosis were noted as responses to a single dose of intravenous (20 mg) dantrolene. The patient was extubated 5 days after transplantation. The kidney function remained within normal limits during the rhabdomyolysis and the entire hospital stay. The patient was discharged 7 weeks later and is surviving with the original liver graft and satisfactory kidney function to date. |
7,282 | U-waves and T-wave peak to T-wave end intervals in patients with catecholaminergic polymorphic ventricular tachycardia, effects of beta-blockers. | Catecholaminergic polymorphic ventricular tachycardia (CPVT) is characterized by risk of polymorphic ventricular tachycardia (pVT) and sudden death during stress. Experimental CPVT models show that delayed afterdepolarization (DAD)-induced triggered activity is the initiating mechanism of pVT, whereas an increase in transmural dispersion of repolarization (TDR) controls degeneration of pVT to ventricular fibrillation. U-wave and T-wave peak to T-wave end interval (TPE) are regarded as electrocardiographic counterparts of DAD and TDR, respectively.</AbstractText>We tested hypotheses that patients with CPVT might show abnormal U-waves and TPE intervals and that beta-blockers could suppress appearance of these repolarization abnormalities.</AbstractText>We reviewed Holter recordings from 19 CPVT patients with a RyR2 mutation (P2328S or V4653F) and from 19 healthy unaffected subjects to record U-waves and TPE intervals as well as to measure beta-blockers' effects on ventricular repolarization by use of an automated computerized program.</AbstractText>The maximal U-wave to T-wave amplitude ratio was 0.8 +/- 0.6 in CPVT patients and 0.4 +/- 0.3 in unaffected subjects (P = .009). Patients with most ventricular extrasystoles had a higher U-wave to T-wave amplitude ratio than those with fewest extrasystoles. Treatment with beta-blockers decreased U-wave amplitude at high heart rates. CPVT patients had longer TPE intervals than unaffected subjects at high heart rates, and beta-blocker treatment shortened their TPE intervals.</AbstractText>Present data support the hypothesis that U-waves associate with the DAD-triggered extrasystolic activity in CPVT patients. Patients with a RyR2 mutation show increased TPE at high heart rates. Beta-blocker treatment suppresses observed repolarization abnormalities in CPVT patients.</AbstractText> |
7,283 | Omega-3 fatty acid: a role in the management of cardiac arrhythmias? | The objective of this study was to review and evaluate published evidence on the use of omega-3 fatty acid in the prevention and treatment of atrial and ventricular arrhythmias. Postulated mechanisms of the antiarrhythmic effects of omega-3 fatty acid are discussed.</AbstractText>Peer-reviewed articles/abstracts published in English language were identified from MEDLINE and Current Content databases (both 1966 to May 15, 2008) using the search terms fish oil, omega-3 fatty acid, sudden death, ventricular arrhythmia, and atrial fibrillation. Citations from available articles were also reviewed for additional references. Abstracts presented at recent professional meetings are also reviewed.</AbstractText>Observational studies and interventional clinical studies published on omega-3 fatty acid or fish consumption and atrial or ventricular arrhythmias and sudden cardiac death are selected. The design and results of the studies are evaluated.</AbstractText>Several mechanisms have been postulated to explain the antiarrhythmic effect of omega-3 fatty acid. It is believed that omega-3 fatty acid has an indirect effect on the autonomic nervous system, inhibits the fast, voltage-dependent sodium and L-type calcium channels, restores a favorable omega-6 fatty acid/omega-3 fatty acid balance, and exerts anti-inflammatory effects. While the majority of observational evidence demonstrated that increased consumption of omega-3 fatty acid was associated with reduction in risk of sudden cardiac death, in ventricular arrhythmia, there was evidence suggesting that omega-3 fatty acid in patients experiencing nonischemic ventricular arrhythmia may be proarrhythmic. Other studies demonstrated a neutral effect. In terms of management of atrial fibrillation, short-term small-scale studies demonstrated that the use of omega-3 fatty acid preoperatively may reduce the incidence of postoperative atrial fibrillation. However, such observations were not consistent with those reported from retrospective cohorts.</AbstractText>Additional studies are needed to evaluate the effect of omega-3 fatty acid before it can be routinely recommended for the management of arrhythmia.</AbstractText> |
7,284 | New horizons in antiarrhythmic therapy: will novel agents overcome current deficits? | Pharmacologic antiarrhythmic therapy is the most commonly used treatment in most patients with atrial fibrillation (AF), but currently available agents are limited by risks that may offset the benefits of sinus rhythm. The development of antiarrhythmic agents with the potential for fewer adverse ventricular effects and less extracardiac toxicity is a primary aim of current investigations. At present, pharmacologic research is actively focused on developing antiarrhythmic agents with multiple or novel ion channel effects. There are 4 agents that act by simultaneously blocking multiple ion channels that are currently under regulatory review: azimilide dihydrochloride, tedisamil, dronedarone, and vernakalant (RSD-1235). In addition, agents with mechanisms of action that differ from those of existing agents (eg, gap junction modulators) are under review, as is the use of nonantiarrhythmic agents (eg, renin-angiotensin system antagonists, statins, n-3 polyunsaturated fatty acids) to alter the cardiac substrate and suppress AF in some patient subtypes. |
7,285 | Atrial fibrillation in Mediterranean spotted fever. | Mediterranean spotted fever (MSF) is a tick-borne acute febrile disease caused by Rickettsia conorii and characterized by fever, maculo-papular rash and a black eschar at the site of the tick bite ('tache noir'). We describe the case of a 58-year-old man affected by MSF who developed atrial fibrillation. The patient presented himself to the hospital after 7 days of fever, malaise and severe headache. Cardiac auscultation revealed a chaotic heart rhythm and an electrocardiogram confirmed atrial fibrillation with a fast ventricular response. Diagnosis of MSF was made after the appearance of a maculo-papular skin rash, and treatment with oral doxycycline was started. An immunofluorescence antibody test confirmed R. conorii infection. The patient recovered after 7 days of treatment. Cardiac arrhythmia is a rare complication of MSF. Inflammation may play a role in the pathogenesis of atrial fibrillation. R. conorii is an intracellular bacterium which could trigger atrial fibrillation. Our patient was previously healthy and had no reported history of cardiac disease. This suggests that heart function should be monitored in MSF patients even in the absence of underlying risk factors. |
7,286 | Patient with hypofibrinolysis-mediated thromboembolism converted to a hypercoagulable/hyperfibrinolytic state via ventricular assist device placement. | Mechanical circulatory support with ventricular assist devices (VADs) for end-stage heart failure has been a focus of intense interest for nearly four decades. Despite improvements in VAD design and biomaterial composition, it is common to administer anti-coagulation (e.g., warfarin, anti-platelet agents) to prevent both device thrombosis and thromboembolism. We present a patient with pre-operative thrombophilia (pulmonary embolism, intracardiac thrombus) and hypofibrinolysis, who subsequently developed hypercoagulability with hyperfibrinolysis with normalization of clot lifespan after left VAD placement. Such complex patient-VAD-hemostatic-state interactions serve as the rationale for continuing investigation of the effects of mechanical circulation on the fibrinolytic system and thrombophilia. |
7,287 | Long-term outcome and risk stratification in dilated cardiolaminopathies. | The aim of this study was to analyze the long-term follow-up of dilated cardiolaminopathies.</AbstractText>Lamin A/C (LMNA) gene mutations cause a variety of phenotypes. In the cardiology setting, patients diagnosed with idiopathic dilated cardiomyopathy (DCM) plus atrioventricular block (AVB) constitute the majority of reported cases.</AbstractText>Longitudinal retrospective observational studies were conducted with 27 consecutive families in which LMNA gene defects were identified in the probands, all sharing the DCM phenotype.</AbstractText>Of the 164 family members, 94 had LMNA gene mutations. Sixty of 94 (64%) were phenotypically affected whereas 34 were only genotypically affected, including 5 with pre-clinical signs. Of the 60 patients, 40 had DCM with AVB, 12 had DCM with ventricular tachycardia/fibrillation, 6 had DCM with AVB and Emery-Dreifuss muscular dystrophy type 2 (EDMD2), and 2 had AVB plus EDMD2. During a median of 57 months (interquartile range 36 to 107 months), we observed 49 events in 43 DCM patients (6 had a later event, excluded from the analysis). The events were related to heart failure (15 heart transplants, 1 death from end-stage heart failure) and ventricular arrhythmias (15 sudden cardiac deaths and 12 appropriate implantable cardioverter-defibrillator interventions). By multivariable analysis, New York Heart Association functional class III to IV and highly dynamic competitive sports for >or=10 years were independent predictors of total events. By a bivariable Cox model, splice site mutations and competitive sport predicted sudden cardiac death.</AbstractText>Dilated cardiomyopathies caused by LMNA gene defects are highly penetrant, adult onset, malignant diseases characterized by a high rate of heart failure and life-threatening arrhythmias, predicted by New York Heart Association functional class, competitive sport activity, and type of mutation.</AbstractText> |
7,288 | J-point elevation in survivors of primary ventricular fibrillation and matched control subjects: incidence and clinical significance. | The purpose of this study was to determine whether J-point elevation is a marker of arrhythmic risk.</AbstractText>J-point elevation has been considered an innocent finding among healthy young individuals (the "early repolarization" pattern). However, this electrocardiogram (ECG) finding is increasingly being associated with idiopathic ventricular fibrillation (VF).</AbstractText>In a case-control study, the ECG of 45 patients with idiopathic VF were compared with those of 124 age- and gender-matched control subjects and with those of 121 young athletes. We measured the height of J-point and ST-segment elevation and counted the presence of slurring in the terminal portion of the R-wave.</AbstractText>J-point elevation was more common among patients with idiopathic VF than among matched control subjects (42% vs. 13%, p = 0.001). This was true for J-point elevation in the inferior leads (27% vs. 8%, p = 0.006) and for J-point elevation in leads I to aVL (13% vs. 1%, p = 0.009). J-point elevation in V(4) to V(6) occurred with equal frequency among patients and matched control subjects (6.7% vs. 7.3%, p = 0.86). Male subjects had J-point elevation more often than female subjects and young athletes had J-point elevation more often than healthy adults but less often than patients with idiopathic VF. The presence of ST-segment elevation or QRS slurring did not add diagnostic value to the presence of J-point elevation.</AbstractText>J-point elevation is found more frequently among patients with idiopathic VF than among healthy control subjects. The frequency of J-point elevation among young athletes is intermediate (higher than among healthy adults but lower than among patients with idiopathic VF).</AbstractText> |
7,289 | Symptomatic ventricular tachyarrhythmia is associated with delayed gadolinium enhancement in cardiac magnetic resonance imaging and with elevated plasma brain natriuretic peptide level in hypertrophic cardiomyopathy. | Delayed gadolinium enhancement (DGE) in cardiac magnetic resonance (CMR) imaging indicates the areas with myocardial fibrosis, which are suggested to be arrhythmogenic substrate in hypertrophic cardiomyopathy (HCM). Elevated brain natriuretic peptide (BNP) is associated with cardiovascular events in HCM. We investigated the grade of DGE in CMR and plasma BNP levels in HCM patients with or without symptomatic ventricular tachycardia (VT) or ventricular fibrillation (VF).</AbstractText>We recruited 26 consecutive untreated HCM patients without any symptoms of heart failure. They were divided into 2 groups: (1) patients with symptomatic VT/VF [VT/VF(+) group, n=6]; (2) patients without symptomatic VT/VF [VT/VF(-) group, n=20]. CMR was performed to evaluate left ventricular geometry and the grade of DGE. Plasma BNP levels, left ventricular mass index, and the number of segments with positive DGE were greater in the VT/VF(+) group than in the VT/VF(-) group (698.1+/-387.6 vs. 226.9+/-256.8 pg/ml, p=0.006; 152.3+/-49.5 vs. 89.5+/-24.1 g/m(2), p=0.003; 9.7+/-5.7 vs. 3.5+/-3.3, p=0.013). On logistic regression, adjusted odds ratio for symptomatic VT/VF was 214 for logBNP (95% confidence interval [CI] 1.2-37,043, p=0.04) and 1.54 for DGE score (95% CI 1.01-2.34, p=0.04).</AbstractText>High plasma BNP levels and the enlarged area of DGE in CMR were associated with symptomatic ventricular tachyarrhythmia. These factors may be useful markers for detecting high-risk patients of sudden cardiac death in HCM.</AbstractText> |
7,290 | Improvement in prognosis of dilated cardiomyopathy in the elderly over the past 20 years. | Although dilated cardiomyopathy (DCM) had a poor prognosis in the past, recent studies have shown better survival. However, little is known about the improvement of prognosis in the elderly. This study sought to clarify the changes in prognosis in elderly patients with DCM over the past 20 years.</AbstractText>We studied 54 consecutive patients with DCM (38 men and 16 women, aged 65-83 years) who were diagnosed at over 65 years of age. The patients were divided into two groups (group A: 12 patients diagnosed before 1990; group B: 42 patients diagnosed after 1990) because after 1990, based on growing evidence from large-scale, randomized clinical studies, we intentionally increased the use of angiotensin-converting enzyme inhibitors (ACEI) and then beta-blockers at our hospital.</AbstractText>There were no significant differences in age, gender, NYHA functional class, and the prevalence of atrial fibrillation and ventricular tachycardia between the two groups. Left ventricular (LV) size assessed by echocardiography was larger (LV end-diastolic diameter, 67+/-5.9 versus 62+/-6.6 mm; p=0.039) and LV ejection fraction measured by left ventriculography was lower (ejection fraction, 24+/-9 versus 35+/-10%; p=0.004) in group A. ACEI/angiotensin II type 1 receptor blockers (ARB) (0% versus 88%) or beta-blockers (0% versus 52%) were more frequently used in group B. Antiarrhythmics (class Ia or Ib) (75% versus 14%) were less often used in group B. The 5- and 10-year event-free survival rates for cardiac death were 75.4% and 22.0% in group A versus 81.2% and 71.3% in group B (log-rank test, p=0.014).</AbstractText>The prognosis of DCM patients in the elderly has significantly improved over the past 20 years. The advances in the pharmacologic treatment and earlier diagnosis may have contributed to the better survival.</AbstractText> |
7,291 | Association between serum C-reactive protein elevation and atrial fibrillation after first anterior myocardial infarction. | Elevated inflammatory markers have been found to correlate with higher risk for cardiac events in patients with acute myocardial infarction (AMI). It has been suggested that C-reactive protein (CRP) may be involved in the initiation process of atrial fibrillation (AF). However, the role of CRP levels in the occurence of AF in patients with AMI has not been studied. This study investigated whether CRP is a risk factor for AF in patients with acute anterior MI.</AbstractText>We prospectively evaluated 92 consecutive patients (25 women and 67 men; aged 58 +/- 11 y) with a first acute anterior wall MI. Blood samples were obtained at the time of admission to the hospital, and serum CRP levels were measured by an ultrasensitive immunonephelometry method. All patients were evaluated by echocardiography to measure the left ventricular (LV) diameter and functions. All patients were monitored continuously for the detection of AF in the coronary care unit.</AbstractText>Atrial fibrillation occured in 19 (20%) of 92 patients. Univariate analysis showed that patients with AF had an advanced age (63 +/- 9.9 versus 56.7 +/- 11.7 y, p = 0.034), higher serum CRP level (2.95 +/- 2.5 versus 1.71 +/- 2.12 mg/dL, p = 0.034), larger LV end-systolic volume (74 +/- 15 versus 63 +/- 19, mL p = 0.02), higher LV ejection fraction (31.1 +/- 6.2 versus 38.4 +/- 10%, p = 0.001), and larger left atrial (LA) diameter (37.1 +/- 4.2 versus 34.7 +/- 3.3 mm, p = 0.01). In multivariate analysis, only age (odds ratio [OR]: 1.05, 95% confidence interval [CI]: 1-1.11, p = 0.036) and CRP levels (OR: 1.27, 95% CI: 1-1.59, p = 0.039) were independent predictors of AF.</AbstractText>These results suggest that CRP may be a risk factor for AF in patients with acute anterior wall MI.</AbstractText>Copyright (c) 2008 Wiley Periodicals, Inc.</CopyrightInformation> |
7,292 | Successful conversion of recent-onset atrial fibrillation by sequential administration of up to three antiarrhythmic drugs. | Short-term conversion attempt of recent-onset atrial fibrillation (AF) in the emergency room fails too often. Many patients and doctors still prefer pharmacological to electrical solutions in such cases.</AbstractText>Sequential administration of up to 3 antiarrhythmic drugs of different classes of action (amiodarone, propafenone, and quinidine) may achieve conversion in such patients.</AbstractText>One hundred and forty consecutive patients with recent-onset AF were transferred to the intensive cardiac care unit after a failed 2-h conversion attempt in the emergency room. First-line drug for conversion was continued up to a full dose, and was chosen by AF etiology, or in recurrent AF episodes, empirically. In nonresponders, the failed drug was replaced by a drug of another class, and if the second-line drug failed it was replaced by a drug of the third-line. Electrical cardioversion was the final solution for nonresponders.</AbstractText>Sixty percent of patients reached sinus rhythm by the first-line drug therapy, 34% by the second-line, and 4% by the third-line. Seventy-five percent of patients achieved conversion within 26 h, and 95% of patients achieved conversion within 40 h. Three patients were electrically cardioverted due to hemodynamical instability. Two episodes of Torsade de Pointes ventricular tachycardia were self-terminated.</AbstractText>Sequential usage of up to 3 antiarrhythmic drugs of different classes of action provides almost complete success in conversion of recent-onset AF in patients refractory to short-term conversion attempt in the emergency room.</AbstractText>Copyright (c) 2008 Wiley Periodicals, Inc.</CopyrightInformation> |
7,293 | Catheter ablation of a polymorphic ventricular tachycardia inducing monofocal premature ventricular complex. | Ventricular tachycardia originating from the right ventricular outflow tract (RVOT) is considered benign, but sometimes it causes polymorphic ventricular tachycardia and ventricular fibrillation, resulting in sudden cardiac death. A 58-year-old woman without structural heart disease was admitted for evaluation of recurrent episodes of syncope. Surface ECG showed frequent repetitive premature ventricular contraction (PVC) of RVOT origin. Polymorphic ventricular tachycardia triggered by the same PVC was documented by Holter ECG during an episode of syncope. Radiofrequency catheter ablation was performed to eradicate this PVC. No polymorphic ventricular tachycardia has developed after the procedure, and the patient has had no recurrence of syncope. |
7,294 | Acute myocarditis mimicking lateral myocardial infarction. | We report a case of myocarditis mimicking acute lateral myocardial infarction and treated as such initially, which was complicated by ventricular fibrillation a few hours after admission to the intensive care unit. The correct diagnosis was rapidly made using a low-dose delayed-enhanced cardiac multidetector computed tomography scan performed immediately after a normal coronary angiogram, demonstrating typical myocardial late hyperenhancement and good correlation with delayed enhanced magnetic resonance imaging. This case suggests that myocarditis can be accurately diagnosed by delayed-enhanced cardiac multidetector computed tomography in an emergency setting. The other lesson from this case is that patients presenting with severe clinical symptoms, important ECG signs and high myocardial enzyme levels should be closely monitored for at least 72 hours, even when myocardial infarction has been excluded. |
7,295 | Resveratrol attenuates ventricular arrhythmias and improves the long-term survival in rats with myocardial infarction. | The effects of resveratrol treatment on ventricular arrhythmia, survival, and late cardiac remodeling were evaluated in rats with myocardial infarction (MI).</AbstractText>Three groups of rats (S: ham-operated, MI, and MI pre-treated with resveratrol) were treated in an in vivo MI model by ligation of left anterior descending coronary artery. The electrocardiogram signals were monitored and recorded for 24 h using an implanted telemetry transmitter. The incidence of ventricular arrhythmias during the first 24-h after MI was also evaluated. Meanwhile, invasive in vivo electrophysiology with pacing in the right ventricle was performed in each group to assess the inducibility of ventricular arrhythmias.</AbstractText>Administration of resveratrol significantly suppressed the MI-induced ventricular tachycardia and ventricular fibrillation (0.4 +/- 0.2 in Resv group vs. 7.1 +/- 2.2 in MI group episodes per hour per rat, P < 0.01). Data also showed that the incidence of inducible ventricular tachycardia was lower in the Resv group than the MI group (46% vs. 81%, P < 0.01). The infarct size and mortality in the Resv group at 14 weeks were reduced by 20% and 33%, respectively, compared with the MI groups. Results from patch clamp recording revealed that resveratrol inhibited L-type calcium current (I (Ca-L)), and selectively enhanced ATP-sensitive K(+) current (I (K,ATP)) in a concentration-dependent manner.</AbstractText>These results suggested that the emerging anti-arrhythmic character induced by resveratrol treatment in rat hearts could be mainly accounted for by inhibition of I (Ca-L) and enhancement of I (K,ATP). Administration of resveratrol also improved the long-term survival by suppressing left ventricular remodeling.</AbstractText> |
7,296 | Reduction of right ventricular pacing in patients with sinus node dysfunction through programming a long atrioventricular delay along with the DDIR mode. | Right ventricular (RV) pacing increases the incidence of atrial fibrillation (AF) and hospitalization rate for heart failure. Many patients with sinus node dysfunction (SND) are implanted with a DDDR pacemaker to ensure the treatment of slowly conducted atrial fibrillation and atrioventricular (AV) block. Many pacemakers are never reprogrammed after implantation. This study aims to evaluate the effectiveness of programming DDIR with a long AV delay in patients with SND and preserved AV conduction as a possible strategy to reduce RV pacing in comparison with a nominal DDDR setting including an AV search hysteresis.</AbstractText>In 61 patients (70 +/- 10 years, 34 male, PR < 200 ms, AV-Wenckebach rate at > or =130 bpm) with symptomatic SND a DDDR pacemaker was implanted. The cumulative prevalence of right ventricular pacing was assessed according to the pacemaker counter in the nominal DDDR-Mode (AV delay 150/120 ms after atrial pacing/sensing, AV search hysteresis active) during the first postoperative days and in DDIR with an individually programmed long fixed AV delay after 100 days (median).</AbstractText>With the nominal DDDR mode the median incidence of right ventricular pacing amounted to 25.2%, whereas with DDIR and long AV delay the median prevalence of RV pacing was significantly reduced to 1.1% (P < 0.001). In 30 patients (49%) right ventricular pacing was almost completely (<1%) eliminated, n = 22 (36%) had >1% <20% and n = 4 (7%) had >40% right ventricular pacing. The median PR interval was 161 ms. The median AV interval with DDIR was 280 ms.</AbstractText>The incidence of right ventricular pacing in patients with SND and preserved AV conduction, who are treated with a dual chamber pacemaker, can significantly be reduced by programming DDIR with a long, individually adapted AV delay when compared with a nominal DDDR setting, but nonetheless in some patients this strategy produces a high proportion of disadvantageous RV pacing. The DDIR mode with long AV delay provides an effective strategy to reduce unnecessary right ventricular pacing but the effect has to be verified in every single patient.</AbstractText> |
7,297 | Anticoagulant drugs in noncompaction: a mandatory therapy? | Noncompaction of left ventricular myocardium is a rare congenital cardiomyopathy resulting from an incomplete myocardial morphogenesis that leads to the persistence of the embryonic myocardium. This condition is characterized by a thin compacted epicardial and an extremely thickened endocardial layer with prominent trabeculations and deep intertrabecular recesses. It is not clear, in noncompaction of myocardium, whether intertrabecular recesses could be responsible for thrombi formation and thromboembolic complications.</AbstractText>The prevalence of stroke and echocardiographic finding of thrombus was evaluated in a continuous series of 229 patients (men and women) affected by noncompaction of the left ventricular myocardium, who were included in the SIEC registry. We excluded patients affected by atrial fibrillation.</AbstractText>The mean age of the patients was 49.5 years. Fifty percent of the patients were affected by a ventricular systolic dysfunction. The mean period of follow-up was 7.3 years. Only four patients had a history of ischemic stroke. A large thrombus into the left ventricular chamber was observed in a 1-year-old child affected by Behcet's disease (high risk of thrombi formation).</AbstractText>Noncompaction of the left ventricular myocardium, by itself, does not seem to be a risk factor for stroke or embolic results, so there is no indication for oral anticoagulant therapy.</AbstractText> |
7,298 | Characterization of multiple spiral wave dynamics as a stochastic predator-prey system. | A perspective on systems containing many action potential waves that, individually, are prone to spiral wave breakup is proposed. The perspective is based on two quantities, "predator" and "prey," which we define as the fraction of the system in the excited state and in the excitable but unexcited state, respectively. These quantities exhibited a number of properties in both simulations and fibrillating canine cardiac tissue that were found to be consistent with a proposed theory that assumes the existence of regions we call "domains of influence," each of which is associated with the activity of one action potential wave. The properties include (i) a propensity to rotate in phase space in the same sense as would be predicted by the standard Volterra-Lotka predator-prey equations, (ii) temporal behavior ranging from near periodic oscillation at a frequency close to the spiral wave rotation frequency ("type-1" behavior) to more complex oscillatory behavior whose power spectrum is composed of a range of frequencies both above and, especially, below the spiral wave rotation frequency ("type-2" behavior), and (iii) a strong positive correlation between the periods and amplitudes of the oscillations of these quantities. In particular, a rapid measure of the amplitude was found to scale consistently as the square root of the period in data taken from both simulations and optical mapping experiments. Global quantities such as predator and prey thus appear to be useful in the study of multiple spiral wave systems, facilitating the posing of new questions, which in turn may help to provide greater understanding of clinically important phenomena such as ventricular fibrillation. |
7,299 | The effect of preoperative circadian blood pressure pattern on early postoperative outcomes in patients with coronary artery bypass graft surgery. | The aim of this prospective study was to evaluate the relationship between preoperative circadian blood pressure pattern and early postoperative course in patients undergoing coronary artery bypass graft (CABG) surgery.</AbstractText>One hundred and thirty patients planning to undergo isolated CABG operation were included to the study (80 men; 50 women). All patients were studied with ambulatory blood pressure monitoring performed 24 hours before surgery and were divided into 2 groups according with presence (79 patients) or absence (51 patients) of dipper phenomenon. Non-dippers were defined as those with a nocturnal reduction of systolic and diastolic blood pressures of less than 10% of daytime pressures. Both groups were compared with each other from the aspect of postoperative need for intraaortic balloon counterpulsation (IABP), inotropic drug support, extubation time, length of intensive care unit and hospitalization stays, renal failure, stroke, malignant ventricular arrhythmia, atrial fibrillation, postoperative myocardial infarction and cardiac mortality. Statistical analyses were performed using Chi-square, unpaired t and Mann-Whitney U tests. Logistic regression analysis was performed to establish associations of non-dipper phenomenon with the risk of postoperative complications.</AbstractText>When compared with the dipper patients, need for inotropic medications (37.5% vs. 62.5%), low cardiac output syndrome (30.4% vs. 69.6%), postoperative myocardial infarction (28.6% vs. 71.4%) and malignant ventricular arrhythmias (27.8% vs. 72.2%) were higher in the non-dipper patients (p<0.05 for all). Logistic regression analysis demonstrated that non-dipper phenomenon after CABG was associated with longer cardiopulmonary bypass time (OR=1.038, 95%CI 1.016-1,060, p=0.001), more need for postoperative inotropic agent (OR=4.014, 95%CI 1.235-13,047, p=0.021) and postoperative IABP (OR=6.625, 95%CI 1.564-28.069, p=0.01) support, higher risk of low cardiac output syndrome (OR=4.159, 95%CI 0.921-18.775, p=0.064), malignant ventricular arrhythmia (OR=4.653, 95%CI 0.964-22,456, p=0.056) and postoperative myocardial infarction (OR=7.629, 95%CI 1.448-40.177, p=0.017).</AbstractText>Dipper and non-dipper phenomenon can be used as a simple analysis tool for assessing early postoperative mortality and morbidity.</AbstractText> |
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