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15,000 | The role of photon scattering in voltage-calcium fluorescent recordings of ventricular fibrillation. | Recent optical mapping studies of cardiac tissue suggest that membrane voltage (V(m)) and intracellular calcium concentrations (Ca) become dissociated during ventricular fibrillation (VF), generating a proarrhythmic substrate. However, experimental methods used in these studies may accentuate measured dissociation due to differences in fluorescent emission wavelengths of optical voltage/calcium (V(opt)/Ca(opt)) signals. Here, we simulate dual voltage-calcium optical mapping experiments using a monodomain-Luo-Rudy ventricular-tissue model coupled to a photon-diffusion model. Dissociation of both electrical, V(m)/Ca, and optical, V(opt)/Ca(opt), signals is quantified by calculating mutual information (MI) for VF and rapid pacing protocols. We find that photon scattering decreases MI of V(opt)/Ca(opt) signals by 23% compared to unscattered V(m)/Ca signals during VF. Scattering effects are amplified by increasing wavelength separation between fluorescent voltage/calcium signals and respective measurement-location misalignment. In contrast, photon scattering does not affect MI during rapid pacing, but high calcium dye affinity can decrease MI by attenuating alternans in Ca(opt) but not in V(opt). We conclude that some dissociation exists between voltage and calcium at the cellular level during VF, but MI differences are amplified by current optical mapping methods. |
15,001 | Outpatient approach to palpitations. | Palpitations are a common problem seen in family medicine; most are of cardiac origin, although an underlying psychiatric disorder, such as anxiety, is also common. Even if a psychiatric comorbidity does exist, it should not be assumed that palpitations are of a noncardiac etiology. Discerning cardiac from noncardiac causes is important given the potential risk of sudden death in those with an underlying cardiac etiology. History and physical examination followed by targeted diagnostic testing are necessary to distinguish a cardiac cause from other causes of palpitations. Standard 12-lead electrocardiography is an essential initial diagnostic test. Cardiac imaging is recommended if history, physical examination, or electrocardiography suggests structural heart disease. An intermittent event (loop) monitor is preferred for documenting cardiac arrhythmias, particularly when they occur infrequently. Ventricular and atrial premature contractions are common cardiac causes of palpitations; prognostic significance is dictated by the extent of underlying structural heart disease. Atrial fibrillation is the most common arrhythmia resulting in hospitalization; such patients are at increased risk of stroke. Patients with supraventricular tachycardia, long QT syndrome, ventricular tachycardia, or palpitations associated with syncope should be referred to a cardiologist. |
15,002 | Effects of the novel amiodarone-like compound SAR114646A on cardiac ion channels and ventricular arrhythmias in rats. | Amiodarone is the "gold standard" for current antiarrhythmic therapy because it combines efficacy with good hemodynamic and electrophysiological tolerance. Amiodarone is effective against both atrial and ventricular arrhythmias by intravenous (i.v.) or oral route. However, the i.v. formulation has limitations. Therefore, we identified SAR114646A, an amiodarone-like antiarrhythmic agent with good aqueous solubility suitable for i.v. application. Patch-clamp experiments were performed with isolated cardiomyocytes from guinea pigs and rats. In guinea pig ventricular cardiomyocytes, the fast Na(+) channel and the L-type Ca(2+) channels were blocked by SAR114646A with half-maximal concentrations (IC(50)) of 2.0 and 1.1 μM, respectively. The tail current of the fast activating rectifying potassium channel I(Kr) was blocked with an IC(50) value of 0.6 μM, whereas the IC(50) values for inhibition of the I(Ks) and I(K1) channels was >10 μM. ATP-sensitive K(+) channels were evoked by application of the channel opener rilmakalim (3 μM). SAR114646A blocked this current with an IC(50) value of 2.8 μM. In guinea pig atrial cardiomyocytes, carbachol (1 μM) was used to activate the I(KACh) and SAR114646A inhibited this current with IC(50) of 36.5 nM. The transient outward current I(to) and the sustained current I(sus) were investigated in rat ventricular myocytes. SAR114646A blocked these currents with IC(50) of 1.8 and 1.2 μM, respectively. When expressed in Chinese hamster ovary cells, the currents hKv1.5 and hHCN4 were inhibited with IC(50) values of 1.1 and 0.4 μM, respectively. Micropuncture experiments in isolated rabbit left atria revealed that SAR114646A prolonged the 50% repolarization significantly at 3 and 10 μM. In guinea pig papillary muscle, the APD at 90% of repolarization was slightly prolonged at 3 and 10 μM. SAR114646A demonstrates antiarrhythmic activity in anaesthetised rats, subjected to 5 min ischemia followed by 10 min reperfusion, where 1 mg/kg of SAR114646A applied as i.v. bolus 5 min prior to ischemia, decreased mortality to 0% compared to 80% under control conditions. In conclusion, SAR114646A is a multichannel blocker with improved water solubility, compared to amiodarone. In contrast to amiodarone, SAR114646A also blocks the K(+) channels I(to) and I(sus). A potent antiarrhythmic effect as observed in rats can also be expected in other animal models. |
15,003 | Aortic bifurcation rupture after blunt abdominal trauma in a child: a case report. | Blunt trauma to the abdomen resulting in aortic injury is rare in children with only a few case reports in the past 40 years. We describe the diagnosis and management of a 2-year-old boy who survived an aortic bifurcation rupture after blunt trauma. |
15,004 | Global epidemiology and demographics of commotio cordis. | The commotio cordis literature has largely focused on events occurring in the United States. However, with enhanced public awareness, commotio cordis has been increasingly recognized internationally as a cause of cardiac arrest and sudden death due to blunt nonpenetrating chest blows.</AbstractText>This study sought to characterize the demographics of commotio cordis globally in comparison to the U.S. experience.</AbstractText>This study used interrogation of the Commotio Cordis Registry (Minneapolis, Minnesota).</AbstractText>We report 60 cases of commotio cordis occurring outside the United States from 19 countries (most commonly the United Kingdom and Canada) on 5 continents and compared these events to 2:3 occuring in the U.S. In the 2 groups, events were largely similar demographically, including frequency of survival (26% in U.S. vs 25%; P = .84), and the striking male predominance evident in both groups (i.e., 95%), although non-U.S. victims were somewhat older (19 ± 13 vs 15 ± 9; P = .002). Not unexpectedly, the groups differed with baseball/softball and football predominant in the United States (55% of events) and soccer, cricket, and hockey most common internationally (47% of events). Notably, the frequency with which soccer participation caused commotio cordis was much more common than expected, particularly in non-U.S. athletes (20% vs 3% U.S.; P < .001).</AbstractText>Commotio cordis demonstrates a global occurrence, very similar demographically in the United States and internationally. However, the frequency with which chest blows from soccer balls caused commotio cordis events (particularly during sports played internationally) seems to contradict the prevailing notion that air-filled projectiles convey less risk for ventricular fibrillation than do those with solid cores (e.g., baseball or lacrosse balls).</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,005 | The impact of increased chest compression fraction on return of spontaneous circulation for out-of-hospital cardiac arrest patients not in ventricular fibrillation. | Greater chest compression fraction (CCF, or proportion of CPR time spent providing compressions) is associated with better survival for out-of-hospital cardiac arrest (OOHCA) patients in ventricular fibrillation (VF). We evaluated the effect of CCF on return of spontaneous circulation (ROSC) in OOHCA patients with non-VF ECG rhythms in the Resuscitation Outcomes Consortium Epistry.</AbstractText>This prospective cohort study included OOHCA patients if: not witnessed by EMS, no automated external defibrillator (AED) shock prior to EMS arrival, received >1 min of CPR with CPR process measures available, and initial non-VF rhythm. We reviewed the first 5 min of electronic CPR records following defibrillator application, measuring the proportion of compressions/min during the resuscitation.</AbstractText>Demographics of 2103 adult patients from 10 U.S. and Canadian centers were: mean age 67.8; male 61.2%; public location 10.6%; bystander witnessed 32.9%; bystander CPR 35.4%; median interval from 911 to defibrillator turned on 8 min:27 s; initial rhythm asystole 64.0%, PEA 28.0%, other non-shockable 8.0%; median compression rate 110/min; median CCF 71%; ROSC 24.2%; survival to hospital discharge 2.0%. The estimated linear effect on adjusted odds ratio with 95% confidence interval (OR; 95%CI) of ROSC for each 10% increase in CCF was (1.05; 0.99, 1.12). Adjusted (OR; 95%CI) of ROSC for each CCF category were: 0-40% (reference group); 41-60% (1.14; 0.72, 1.81); 61-80% (1.42; 0.92, 2.20); and 81-100% (1.48; 0.94, 2.32).</AbstractText>This is the first study to demonstrate that increased CCF among non-VF OOHCA patients is associated with a trend toward increased likelihood of ROSC.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
15,006 | The prevalence and the prognostic value of microvolt T-wave alternans in patients with hypertrophic cardiomyopathy. | Nonsustained ventricular tachycardia (nVT) may have ominous implications for patients with hypertrophic cardiomyopathy (HCM). The microvolt T-wave alternans (TWA) has been proposed as a noninvasive tool-identifying patients at risk of sudden cardiac death and ventricular tachycardia/fibrillation (VT/VF). The aim of the study was to determine the significance of TWA in predicting nVT episodes and compare how other electrocardiographic parameters can predict the occurrence of nVT.</AbstractText>The study group consisted of 88 patients with HCM. TWA was assessed during exercise test using the CH2000 system. All patients underwent Holter monitoring (HM) within 2-4 weeks before TWA test (preexercise HM1) and immediately after (postexercise HM2). During HM, we analyzed: arrhythmias, QT intervals, the presence of late ventricular potentials (LP), heart rate variability, heart rate turbulence.</AbstractText>Depending on TWA results, the patients were divided into two groups: TWA+; 46 patients (52.3%) with positive/indeterminate results, and TWA-; 42 patients (47.7%) with negative results. The nVT episodes were more frequent among TWA(+) both in HM1 and HM2. The presence of TWA increases the risk of postexercise nVT over twenty times (OR = 21.03). Moreover, in HM1, QTc and LP, and in HM2, again QTc and N-terminal precursor of brain natriuretic peptide proved to be significant predictors of nVT. The addition of TWA to the models did not improve the arrhythmia risk assessment.</AbstractText>Repolarization abnormality plays an important role in generating nVT in patients with HCM, but TWA does not specifically predict the risk of arrhythmic end point.</AbstractText>©2011, Wiley Periodicals, Inc.</CopyrightInformation> |
15,007 | Usefulness of acute delirium as a predictor of adverse outcomes in patients >65 years of age with acute decompensated heart failure. | Delirium is an acute confusional state that is very prevalent in older patients hospitalized with acute decompensated heart failure (ADHF). The association between delirium and ADHF outcome has not been well described. We analyzed 883 consecutive patients >65 years of age admitted with ADHF. Acute delirium was diagnosed based on the Confusion Assessment Method. Delirious patients (total n = 151) had an increased in-hospital all-cause death compared to nondelirious patients (n = 17, 11%, vs n = 45, 6%; adjusted odds ratio [OR] 1.93, 95% confidence interval [CI] 1.07 to 3.48, p = 0.02). Of those surviving to discharge (n = 821), on multivariable logistic regression analysis, delirium was independently associated with increased risk of 30-day (adjusted OR 4.24, 95% CI 2.77 to 6.47, p <0.001) and 90-day (adjusted OR 3.72, 95% CI 2.51 to 5.54, p <0.001) rehospitalizations for ADHF and higher nursing home placement (adjusted OR 2.70, 95% CI 1.59 to 5.30, p <0.001) after adjusting for age, gender, cardiac risk factors, dementia, activities of daily living, instrumental activities of daily living, coronary artery disease, atrial fibrillation, left ventricular ejection fraction, angiotensin-converting enzyme inhibitor and/or angiotensin receptor blocker, β blockers, Charlson co-morbidity index, and other potential confounders. Furthermore, delirium was strongly associated with 90-day all-cause mortality in patients discharged from the hospital (adjusted hazard ratio 2.10, CI 1.53 to 2.88, p <0.0001). In conclusion, acute delirium serves as an important prognostic determinant of in-hospital and posthospital discharge outcomes including increased ADHF readmission risk in older hospitalized patients with ADHF. Thus, delirium plays an important role in the risk stratification and prognosis of patients with ADHF. |
15,008 | [The driver's illness as a cause of traffic accidents]. | Fatal motor vehicle accidents (fMVAs) as well as accidents involving pedestrians or bicyclists in Uusimaa county in 2008 were reviewed. Of the fMVAs, acute disease attacks while driving caused 26.5% (9/34) of the drivers' deaths. This equalled with the number of alcohol-related fatal accidents. Heart attack was the main cause (7/9 disease attacks). Three bicyclists (3/14; 21%) died for health reasons; two for ventricular fibrillation and one for alcohol intoxication probably combined with cardiac arrhythmia. Diseases served also as background causes for fMVAs. Education of health care personnel on medical conditions and driving should be improved. |
15,009 | Ablation of Atrial Fibrillation in the Elderly: Current Evidence and Evolving Trends. | Management of atrial fibrillation in the elderly presents unique challenges, including deciding upon the best treatment strategy: rate control versus rhythm control. The decision to pursue one treatment strategy over another is based on understanding the underlying disorder: symptomatology from atrial fibrillation itself versus symptoms due to a rapid ventricular response from atrial fibrillation. The ablation strategies for the treatment of atrial fibrillation include atrioventricular junction ablation and pulmonary vein isolation. This review discusses the data on ablation of atrial fibrillation in the elderly, with an emphasis on issues regarding safety and efficacy in this population. |
15,010 | Left ventricular hypertrophy: major risk factor in patients with hypertension: update and practical clinical applications. | Left ventricular hypertrophy is a maladaptive response to chronic pressure overload and an important risk factor for atrial fibrillation, diastolic heart failure, systolic heart failure, and sudden death in patients with hypertension. Since not all patients with hypertension develop left ventricular hypertrophy, there are clinical findings that should be kept in mind that may alert the physician to the presence of left ventricular hypertrophy so a more definitive evaluation can be performed using an echocardiogram or cardiovascular magnetic resonance. Controlling arterial pressure, sodium restriction, and weight loss independently facilitate the regression of left ventricular hypertrophy. Choice of antihypertensive agents may be important when treating a patient with hypertensive left ventricular hypertrophy. Angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers followed by calcium channel antagonists most rapidly facilitate the regression of left ventricular hypertrophy. With the regression of left ventricular hypertrophy, diastolic function and coronary flow reserve usually improve, and cardiovascular risk decreases. |
15,011 | Low-energy control of electrical turbulence in the heart. | Controlling the complex spatio-temporal dynamics underlying life-threatening cardiac arrhythmias such as fibrillation is extremely difficult, because of the nonlinear interaction of excitation waves in a heterogeneous anatomical substrate. In the absence of a better strategy, strong, globally resetting electrical shocks remain the only reliable treatment for cardiac fibrillation. Here we establish the relationship between the response of the tissue to an electric field and the spatial distribution of heterogeneities in the scale-free coronary vascular structure. We show that in response to a pulsed electric field, E, these heterogeneities serve as nucleation sites for the generation of intramural electrical waves with a source density ρ(E) and a characteristic time, τ, for tissue depolarization that obeys the power law τ ∝ E(α). These intramural wave sources permit targeting of electrical turbulence near the cores of the vortices of electrical activity that drive complex fibrillatory dynamics. We show in vitro that simultaneous and direct access to multiple vortex cores results in rapid synchronization of cardiac tissue and therefore, efficient termination of fibrillation. Using this control strategy, we demonstrate low-energy termination of fibrillation in vivo. Our results give new insights into the mechanisms and dynamics underlying the control of spatio-temporal chaos in heterogeneous excitable media and provide new research perspectives towards alternative, life-saving low-energy defibrillation techniques. |
15,012 | Atrial selective effects of intravenously administered vernakalant in conscious beagle dogs. | Vernakalant is a relatively atrial-selective antiarrhythmic drug approved for the conversion of recent onset atrial fibrillation in Europe and is under regulatory review in the United States. In this study, we examined the effects of intravenously administered vernakalant (5, 10, and 20 mg/kg) on blood pressure, heart rate, and the electrocardiogram in conscious male beagle dogs and compared them with those of orally administered dl-sotalol (32 mg/kg). Vernakalant had no consistent dose-dependent effects on the heart rate or mean arterial pressure. Although vernakalant inhibits I(Kr), it tended to decrease the QTc interval but only at the top dose and later time points. The most striking effect of vernakalant on the electrocardiogram was a dose-dependent and selective slowing of atrial conduction (P-wave duration), with no effect on ventricular conduction (QRS duration). In contrast, treatment with dl-sotalol resulted in a marked and statistically significant prolongation of PR and QTc intervals with no effect on QRS or P-wave duration, consistent with its known class II and III antiarrhythmic actions. These results provide further evidence that vernakalant is unlikely to alter ventricular refractoriness or conduction at plasma concentrations in excess of those necessary for conversion of atrial fibrillation to sinus rhythm in patients. |
15,013 | Outcomes of cardiac perforation complicating catheter ablation of ventricular arrhythmias. | Cardiac perforation is a recognized complication of catheter ablation procedures, most commonly encountered during ablation of atrial fibrillation. The study aims to investigate the incidence, management, and hospital outcomes of cardiac perforation complicating catheter ablation for ventricular arrhythmias.</AbstractText>Consecutive patients undergoing catheter ablation for ventricular arrhythmias at a tertiary referral center were included in this retrospective analysis. Of 1152 consecutive catheter ablation procedures in 892 patients over 12 years, 11 procedures (1.0%) were complicated by ventricular perforation. Emergent pericardial drainage and surgical repair were required in 10 (91%) and 6 (55%) cases, respectively. No perforation was apparent in patients with prior cardiac surgery. More than half of the perforations (6 of 11) occurred in the context of steam pops during radiofrequency ablation and were more likely to require surgical repair (P=0.07). Intra-aortic balloon counterpulsation, left ventricular assist device, and biventricular assist device were used in 2 patients, 1 patient, and 1 patient, respectively. Of 6 cases in which the site of perforation could be determined at cardiac surgery, 5 were in the right ventricle (4 outflow tract, 1 free wall) and only 1 was located in the left ventricle. All patients survived to discharge.</AbstractText>Ventricular perforation and tamponade occurs in 1% of ventricular ablation procedures and in this series, occurred only in patients without a history of prior cardiac surgery. More than half the patients required surgical repair. Perforation is often associated with steam pops and emergent surgical repair is often required when perforation occurs after a steam pop.</AbstractText> |
15,014 | Asymmetric dimethylarginine predicts appropriate implantable cardioverter-defibrillator intervention in patients with left ventricular dysfunction. | More precise characterization of risk factors for occurring ventricular arrhythmia in patients (pts) with primary prevention implantable cardioverter-defibrillator (ICD) therapy is critical. We sought to investigate whether biomarkers of nitric oxide metabolism can predict the occurrence of ventricular tachyarrhythmias and might be used as risk markers in these pts.</AbstractText>Plasma levels of l-arginine (Arg), asymmetric dimethylarginine (ADMA), symmetrical dimethylarginine (SDMA), monomethyl l-arginine, and nitrite/nitrate were examined in 106 consecutive pts (mean age 65 years, 97 male, mean LV-EF 24 ± 6%), with ischaemic (n= 82) or non-ischaemic cardiomyopathy (n= 24) who underwent ICD implantation for primary prevention of SCD. Appropriate ICD intervention was assessed during a mean follow-up of 344 days, and occurred in 18 of 106 (17%) pts. Asymmetric dimethylarginine plasma levels were significantly higher in pts with appropriate ICD intervention compared with those without any ICD intervention (0.564 ± 0.083 μmol/L vs. 0.513 ± 0.088 μmol; P= 0.027). The Arg/ADMA ratio was found lower in pts with appropriate ICD intervention than in those without ICD intervention (144.71 ± 32.50 vs. 175.29 ± 41.29; P= 0.002). Univariate Cox regression showed that ADMA (P = 0.028) and the Arg/ADMA ratio (P = 0.003) were associated with a higher incidence of appropriate ICD intervention. In a multivariable Cox regression analysis, an ADMA concentration above the 50th centile was independently associated with appropriate ICD intervention, revealing a hazard ratio (HR) of 4.21 (CI 95 %: 1.14-15.63; P = 0.028, Table 4). An Arg/ADMA ratio below the 25th centile had a HR of 3.83 (1.360-10.87; P = 0.011).</AbstractText>Asymmetric dimethylarginine and the Arg/ADMA ratio seem to be new biomarkers for the prediction of ventricular tachycardia/ventricular fibrillation episodes and of appropriate ICD intervention in pts with left ventricular ejection fraction dysfunction (LV-EF ≤ 35%), suggesting a value for risk stratification in these pts.</AbstractText> |
15,015 | Live 3D TEE demonstrates and guides the management of prosthetic mitral valve obstruction. | A 43-year-old woman, with a remote history of rheumatic mitral stenosis and a St. Jude prosthetic mitral valve replacement, presented with shortness of breath and palpitations, shortly after a long flight. On admission, atrial fibrillation with a rapid ventricular response was noted in the setting of a long history of noncompliance with her anticoagulation. Transesophageal echocardiography (TEE) demonstrated multiple laminated thrombi in the left atrial appendage. Live three-dimensional (3D) TEE confirmed this diagnosis and demonstrated an immobile posterior leaflet of the mitral prosthesis, which had direct implications in her management. She successfully underwent surgery for mitral valve replacement, left atrial appendage ligation, and a Maze procedure on the following day. The multiple thrombi within the atrial appendage were confirmed intraoperatively and pannus formation was determined to be the etiology of the leaflet immobility. |
15,016 | Intramural activation during early human ventricular fibrillation. | We investigated patterns of intramural activation in early human ventricular fibrillation (VF) and hypothesized that intramural reentry colocalizes to sites with increased intramural fibrosis.</AbstractText>Thirteen human Langendorff hearts were used for this study. Twenty-five plunge needles (4 unipoles/needle) were used to map 100 intramural sites. For the global mapping component, 11 20-s episodes of early VF were studied in 6 hearts. Simultaneous activation of all 4 electrodes was the most common pattern observed in 48.7% of needles, followed by an endocardial-to-epicardial activation pattern (9.8% of needles) and epicardial-to-endocardial activation pattern (5.5% of needles); 19.3% of needles had nonuniform multidirectional patterns. In 2 orthogonal planes, 1 parallel and 1 perpendicular to the epicardium and endocardium, reentry was detected in 14.3% of beats at any 1 level, and 5.8% of these were transmural. Simultaneous mapping of the epicardium and endocardium in 5 hearts detected concurrently rotating rotors with similar chirality and cycle length, suggesting the presence of transmural scroll waves (n=6), which was confirmed by high-resolution fixed-space mapping in 2 of those hearts plus 1 additional heart. Transmural optical mapping in 1 additional heart confirmed simultaneous epicardial and endocardial activation. Histopathology revealed greater fibrosis at sites of reentry compared to areas without (53.3±11.9% versus 27.5±2.4%, P=0.02).</AbstractText>Intramural activation patterns suggest that early human VF does not organize as multiple reentrant wavefronts but is best explained by transmural scroll wave activation. Intramural reentry localizes to regions of greater intramural fibrosis.</AbstractText> |
15,017 | [Effects of Chinese herbal medicines Shengmai injection and Xuesaitong injection on ventricular fibrillation threshold and connexin 43 expression in rats with myocardial infarction]. | To explore the effects of Shengmai injection and Xuesaitong injection, compound Chinese herbal medicines for replenishing qi and activating blood, on ventricular fibrillation threshold, heart structure and connexin 43 (Cx43) expression in rats with myocardial infarction (MI).</AbstractText>One hundred male SD rats were randomly divided into sham operation group, model group, Yiqi Huoxue (YQHX) group (Shengmai injection plus Xuesaitong injection) and captopril group. MI model of rats was established by ligating left anterior descending coronary artery, and rats in sham operation group were prepared in the same way except for the ligation of coronary artery. Rats were treated with corresponding drugs for 1 month from next day after modeling. After treatment ventricular fibrillation threshold was detected, and heart weight index, left ventricular internal diameter and percentage of myocardial infarction were measured. Expression of Cx43 mRNA in myocardium was detected by real-time fluorescent quantitative polymerase chain reaction, and expression of Cx43 protein was observed by immunohistochemical method.</AbstractText>Compared with the sham operation group, ventricular fibrillation threshold decreased significantly, heart weight index and left ventricular internal diameter increased, while expressions of Cx43 mRNA and protein decreased remarkably in the model group (P<0.01). Compared with the model group, ventricular fibrillation threshold was increased significantly, heart weight index, left ventricular internal diameter and percentage of myocardial infarction were decreased significantly in the YQHX group and captopril group (P<0.05 or P<0.01). When it comes to expression of Cx43, both Cx43 mRNA and protein expressions were increased remarkably in the YQHX group compared with the model group (P<0.05 or P<0.01), while only density mean and integral optical density of Cx43 protein expression were increased significantly in the captopril group (P<0.05). The enhancements on Cx43 mRNA and positive area sum of Cx43 protein induced by YQHX drugs were stronger than those induced by captopril (P<0.05).</AbstractText>Shengmai injection and Xuesaitong injection have beneficial effects on ventricular fibrillation threshold in rats with MI. The mechanism is related with improving heart structure and reducing Cx43 expression after MI.</AbstractText> |
15,018 | Plitidepsin has a safe cardiac profile: a comprehensive analysis. | Plitidepsin is a cyclic depsipeptide of marine origin in clinical development in cancer patients. Previously, some depsipeptides have been linked to increased cardiac toxicity. Clinical databases were searched for cardiac adverse events (CAEs) that occurred in clinical trials with the single-agent plitidepsin. Demographic, clinical and pharmacological variables were explored by univariate and multivariate logistic regression analysis. Forty-six of 578 treated patients (8.0%) had at least one CAE (11 patients (1.9%) with plitidepsin-related CAEs), none with fatal outcome as a direct consequence. The more frequent CAEs were rhythm abnormalities (n = 31; 5.4%), mostly atrial fibrillation/flutter (n = 15; 2.6%). Of note, life-threatening ventricular arrhythmias did not occur. Myocardial injury events (n = 17; 3.0%) included possible ischemic-related and non-ischemic events. Other events (miscellaneous, n = 6; 1.0%) were not related to plitidepsin. Significant associations were found with prostate or pancreas cancer primary diagnosis (p = 0.0017), known baseline cardiac risk factors (p = 0.0072), myalgia present at baseline (p = 0.0140), hemoglobin levels lower than 10 g/dL (p = 0.0208) and grade ≥2 hypokalemia (p = 0.0095). Treatment-related variables (plitidepsin dose, number of cycles, schedule and/or total cumulative dose) were not associated. Electrocardiograms performed before and after plitidepsin administration (n = 136) detected no relevant effect on QTc interval. None of the pharmacokinetic parameters analyzed had a significant impact on the probability of developing a CAE. In conclusion, the most frequent CAE type was atrial fibrillation/atrial flutter, although its frequency was not different to that reported in the age-matched healthy population, while other CAEs types were rare. No dose-cumulative pattern was observed, and no treatment-related variables were associated with CAEs. Relevant risk factors identified were related to the patient's condition and/or to disease-related characteristics rather than to drug exposure. Therefore, the current analysis supports a safe cardiac risk profile for single-agent plitidepsin in cancer patients. |
15,019 | Arrhythmias in the coronary care unit. | Symptomatic sustained cardiac arrhythmias are frequently observed in in the coronary care unit and often lead to hemodynamic compromise, especially in the presence of multisystem disease. The predominant arrhythmias noted in intensive care units are tachyarrhythmias, particularly atrial fibrillation and flutter, and ventricular tachycardia. Bradycardias, arguably less life-threatening than tachyarrhythmias, can arise from sinus node dysfunction or atrioventricular conduction block; transient vagally-mediated bradycardias are frequently encountered as well. Prompt diagnosis of the patient with tachycardia is critical as treatment depends on the accurate diagnosis of tachycardia mechanism. The electrocardiogram remains the most important diagnostic tool for the evaluation of both wide and narrow complex tachycardia. The electrocardiographic diagnosis of wide complex tachycardia is based on evaluation of atrioventricular relationship and QRS morphology while the diagnosis of narrow complex tachycardia is based on the location and morphology of P waves. It is important for critical care specialists to understand the principles of cardiac arrhythmia diagnosis and remain current with the recent advances in the pharmacologic and non-pharmacologic management of patients with arrhythmias. |
15,020 | Therapeutic hypothermia after out-of-hospital cardiac arrest: evaluation of a regional system to increase access to cooling. | Therapeutic hypothermia (TH) improves survival and confers neuroprotection in out-of-hospital cardiac arrest (OHCA), but TH is underutilized, and regional systems of care for OHCA that include TH are needed.</AbstractText>The Cool It protocol has established TH as the standard of care for OHCA across a regional network of hospitals transferring patients to a central TH-capable hospital. Between February 2006 and August 2009, 140 OHCA patients who remained unresponsive after return of spontaneous circulation were cooled and rewarmed with the use of an automated, noninvasive cooling device. Three quarters of the patients (n=107) were transferred to the TH-capable hospital from referring network hospitals. Positive neurological outcome was defined as Cerebral Performance Category 1 or 2 at discharge. Patients with non-ventricular fibrillation arrest or cardiogenic shock were included, and patients with concurrent ST-segment elevation myocardial infarction (n=68) received cardiac intervention and cooling simultaneously. Overall survival to hospital discharge was 56%, and 92% of survivors were discharged with a positive neurological outcome. Survival was similar in transferred and nontransferred patients. Non-ventricular fibrillation arrest and presence of cardiogenic shock were associated strongly with mortality, but survivors with these event characteristics had high rates of positive neurological recovery (100% and 89%, respectively). A 20% increase in the risk of death (95% confidence interval, 4% to 39%) was observed for every hour of delay to initiation of cooling.</AbstractText>A comprehensive TH protocol can be integrated into a regional ST-segment elevation myocardial infarction network and achieves broad dispersion of this essential therapy for OHCA.</AbstractText> |
15,021 | Success of ablation for atrial fibrillation in isolated left ventricular diastolic dysfunction: a comparison to systolic dysfunction and normal ventricular function. | The efficacy of radiofrequency ablation for atrial fibrillation (AF) in patients with left ventricular (LV) systolic dysfunction and isolated diastolic dysfunction is uncertain.</AbstractText>A prospective cohort of patients with normal and abnormal LV function underwent ablation for antiarrhythmic drug (AAD)-refractory AF. Three groups were compared: 111 patients with systolic dysfunction, defined as LV ejection fraction (LVEF) ≤40%; 157 patients with isolated diastolic dysfunction but preserved LVEF ≥50%; and 100 patients with normal LV function. The primary end point was AAD-free AF elimination at 1 year after ablation. This end point was achieved in 62% of patients with systolic dysfunction, 75% of those with diastolic dysfunction, and 84% of controls (P=0.007). AF control on or off AADs was achieved in 76% of patients with systolic dysfunction, 85% of those with diastolic dysfunction, and 89% of controls (P=0.08). In the systolic dysfunction group, 49% experienced an increase in LVEF by ≥5% after ablation, of which 64% achieved normal LVEF. In the diastolic dysfunction group, 30% of patients demonstrated at least 1 grade improvement in diastolic dysfunction. Multivariable analysis demonstrated an increased relative risk of arrhythmia recurrence of 1.8 (95% CI, 1.1 to 3.1; P=0.02) in systolic dysfunction and 1.7 (1.0 to 2.7; P=0.04) in isolated diastolic dysfunction compared with normal function.</AbstractText>Although an ablative approach for AF in patients with systolic or diastolic dysfunction is associated with an increased long-term recurrence risk, there is potential for substantial quality-of-life improvement and LV functional benefit.</AbstractText> |
15,022 | An unfortunate case of Pendred syndrome. | To report a patient with Pendred syndrome who developed life-threatening hypokalaemia as an unpredicted consequence of implant-induced imbalance and alcohol dependency, leading to multiple cardiac arrests.</AbstractText>Addenbrooke's Hospital, Cambridge, UK.</AbstractText>Case report and review of the English language literature concerning Pendred syndrome and cochlear implantation in Pendred syndrome patients.</AbstractText>Pendred syndrome is an autosomal recessive disorder which mainly affects the inner ear, thyroid and kidneys. It accounts for 10 per cent of syndromic hearing loss cases. The majority of Pendred syndrome patients are referred to cochlear implant programmes for hearing assessment and therapy. They may also have an underlying metabolic abnormality which is not clinically apparent.</AbstractText>Providing cochlear implants to patients with Pendred syndrome demands extensive knowledge of this condition, in order to avoid potential morbidity.</AbstractText> |
15,023 | Fluoroscopic left ventricular lead position and the long-term clinical outcome of cardiac resynchronization therapy. | To determine the effects of left ventricular (LV) lead tip position on the long-term outcome of cardiac resynchronization therapy (CRT).</AbstractText>Cardiac device therapy center.</AbstractText>Five hundred and fifty-six patients (age 70.4 ± 10.7 years [mean ± standard deviation]).</AbstractText>CRT-pacing or CRT-defibrillation device implantation.</AbstractText>Cardiovascular mortality and events over a maximum follow-up period of 9.1 years.</AbstractText>Hazard ratios (HRs [95% 785]797) for cardiovascular mortality, adjusted for age, gender, QRS duration, heart failure etiology, New York Heart Association class, and presence of diabetes and atrial fibrillation, were derived for LV lead tip positions in terms of veins, circumferential, and longitudinal positions with respect to the LV chamber. For vein position, these were 1.07 (0.74-1.56) for anterolateral vein position and 1.24 (0.79-1.95) for the middle cardiac vein, compared with a posterolateral vein. For circumferential lead tip position, HRs were 1.56 (0.73-3.34) for anterolateral and 1.57 (0.76-3.25) for lateral, compared with posterior positions. For longitudinal lead tip positions, HRs were 1.02 (0.72-1.46) for basal and 1.21 (0.68-2.17) for apical, compared with mid-ventricular positions. The risk of meeting the composite endpoints of cardiovascular death or hospitalizations for heart failure and death from any cause or hospitalizations for major adverse cardiovascular events was similar among the various LV lead tip positions.</AbstractText>The position of the LV lead over the LV free wall, assessed by fluoroscopy, has no influence over the long-term outcome of CRT.</AbstractText>©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.</CopyrightInformation> |
15,024 | Syncope during exercise: just another benign vasovagal event? | In general, syncope in children and adolescents is a benign event. Syncope during exercise may identify patients with a potentially fatal condition. Catecholaminergic polymorphic ventricular tachycardia is characterized by life-threatening ventricular arrhythmias, usually polymorphic ventricular tachycardia or ventricular fibrillation, occurring under conditions of exercise or emotional stress. Catecholaminergic polymorphic ventricular tachycardia is a familial condition that presents with exercise-induced syncope or sudden death in children or young adults. Detailed evaluation should be considered for patients who have syncope during exercise, injure themselves during the fall (i.e., unprotected faint with no antecedent warning prodrome), or who have a family history of syncope, early sudden cardiac death, myocardial disease, or arrhythmias. |
15,025 | Atrial fibrillation and mortality in African American patients with heart failure: results from the African American Heart Failure Trial (A-HeFT). | Atrial fibrillation (AF) is common in patients with heart failure (HF) and portends a worsened prognosis. Because of the low enrollment of African American subjects (AAs) in randomized HF trials, there are little data on AF in AAs with HF. This post hoc analysis reviews characteristics and outcomes of AA patients with AF in A-HeFT.</AbstractText>A total of 1,050 AA patients with New York Heart Association class III/IV systolic HF, well treated with neurohormonal blockade (87% β-blockers, 93% angiotensin-converting enzyme inhibitor and/or angiotensin receptor blocker), were randomized to an added fixed-dose combination of isosorbide dinitrate/hydralazine (FDC I/H) or placebo. Atrial fibrillation was confirmed in 174 (16.6%) patients at baseline and in an additional 9 patients who developed AF during the study, for a final cohort of 183 (17.4%). Comparison of patients with AF versus no AF revealed the following: mean age 61 ± 12 versus 56 ± 13 years (P < .001), systolic blood pressure (BP) 124 ± 18 versus 127 ± 18 mm Hg (P = .044), diastolic BP 74 ± 11 versus 77 ± 10 mm Hg (P = .002), creatinine level 1.4 ± 0.5 versus 1.2 ± 0.5 mg/dL (P < .001), and brain natriuretic peptide 431 ± 443 versus 283 ± 396 pg/mL (P < .001). No significant difference was observed in ejection fraction, left ventricular end-diastolic diameter, or quality-of-life scores. However, AF increased the risk of mortality significantly among AA patients (P = .018), and the use of FDC I/H reduced the risk of mortality in patients with AF (HR 0.21, P = .002).</AbstractText>African Americans with HF and AF (vs no AF) were older, had lower BP, and had higher creatinine and brain natriuretic peptide levels. Mortality and morbidity were worse when AF was present, and these data suggest that there may be an enhanced survival benefit with the use of FDC I/H in AA patients with HF and AF.</AbstractText>Copyright © 2011 Mosby, Inc. All rights reserved.</CopyrightInformation> |
15,026 | Experiment-model interaction for analysis of epicardial activation during human ventricular fibrillation with global myocardial ischaemia. | We describe a combined experiment-modelling framework to investigate the effects of ischaemia on the organisation of ventricular fibrillation in the human heart. In a series of experimental studies epicardial activity was recorded from 10 patients undergoing routine cardiac surgery. Ventricular fibrillation was induced by burst pacing, and recording continued during 2.5 min of global cardiac ischaemia followed by 30 s of coronary reflow. Modelling used a 2D description of human ventricular tissue. Global cardiac ischaemia was simulated by (i) decreased intracellular ATP concentration and subsequent activation of an ATP sensitive K⁺ current, (ii) elevated extracellular K⁺ concentration, and (iii) acidosis resulting in reduced magnitude of the L-type Ca²⁺ current I(Ca,L). Simulated ischaemia acted to shorten action potential duration, reduce conduction velocity, increase effective refractory period, and flatten restitution. In the model, these effects resulted in slower re-entrant activity that was qualitatively consistent with our observations in the human heart. However, the flattening of restitution also resulted in the collapse of many re-entrant waves to several stable re-entrant waves, which was different to the overall trend we observed in the experimental data. These findings highlight a potential role for other factors, such as structural or functional heterogeneity in sustaining wavebreak during human ventricular fibrillation with global myocardial ischaemia. |
15,027 | Clinical study of the electrophysiological effects of ischemic post-conditioning in patients with acute myocardial infarctions. | Ischemic "pre"-conditioning has been shown to have antiarrhythmic effects. The aim of this study was to investigate whether ischemic "post"-conditioning (post-CON) also has antiarrhythmic effects in ST-segment elevation myocardial infarction (STEMI) patients undergoing coronary angioplasty (PCI) as a clinical model of post-CON.</AbstractText>A total of 61 patients suffering from an acute myocardial infarction (AMI) were included. The QT dispersion (QTd) was measured before each balloon inflation (BI) and after deflation (BD) during PCI. The hemodynamic parameters and electrocardiogram were also assessed during PCI. All data were analyzed using a logistic regression analysis. A total of 36 of 61 STEMI patients could be analyzed according to the protocol. The QTd shortened significantly as the BI and BD were repeated (p<0.05). Prior to the PCI, frequent premature ventricular contractions (PVCs) were observed in 5 patients, and the PVCs were remarkably suppressed or disappeared entirely as the BI and BD were repeated. Non-sustained ventricular tachycardia was observed prior to the PCI in 2 patients; this also disappeared as the BI and BD were repeated. Ventricular fibrillation (VF) occurred in 1 patient prior to PCI, necessitating D-C cardioversion. After repeating the BI and BD during PCI, VF no longer recurred.</AbstractText>In the majority of the AMI patients studied, post-CON exhibited significant antiarrhythmic effects as assessed by the change in the QTd. The ventricular dysarrhythmias were also suppressed during the PCI.</AbstractText>Copyright © 2011 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.</CopyrightInformation> |
15,028 | Ranolazine reduces Ca2+ overload and oxidative stress and improves mitochondrial integrity to protect against ischemia reperfusion injury in isolated hearts. | Ranolazine is a clinically approved drug for treating cardiac ventricular dysrhythmias and angina. Its mechanism(s) of protection is not clearly understood but evidence points to blocking the late Na+ current that arises during ischemia, blocking mitochondrial complex I activity, or modulating mitochondrial metabolism. Here we tested the effect of ranolazine treatment before ischemia at the mitochondrial level in intact isolated hearts and in mitochondria isolated from hearts at different times of reperfusion. Left ventricular (LV) pressure (LVP), coronary flow (CF), and O2 metabolism were measured in guinea pig isolated hearts perfused with Krebs-Ringer's solution; mitochondrial (m) superoxide (O2·-), Ca2+, NADH/FAD (redox state), and cytosolic (c) Ca2+ were assessed on-line in the LV free wall by fluorescence spectrophotometry. Ranolazine (5 μM), infused for 1 min just before 30 min of global ischemia, itself did not change O2·-, cCa2+, mCa2+ or redox state. During late ischemia and reperfusion (IR) O2·- emission and m[Ca2+] increased less in the ranolazine group vs. the control group. Ranolazine decreased c[Ca2+] only during ischemia while NADH and FAD were not different during IR in the ranolazine vs. control groups. Throughout reperfusion LVP and CF were higher, and ventricular fibrillation was less frequent. Infarct size was smaller in the ranolazine group than in the control group. Mitochondria isolated from ranolazine-treated hearts had mild resistance to permeability transition pore (mPTP) opening and less cytochrome c release than control hearts. Ranolazine may provide functional protection of the heart during IR injury by reducing cCa2+ and mCa2+ loading secondary to its effect to block the late Na+ current. Subsequently it indirectly reduces O2·- emission, preserves bioenergetics, delays mPTP opening, and restricts loss of cytochrome c, thereby reducing necrosis and apoptosis. |
15,029 | Autoantibodies and cardiac arrhythmias. | Autoimmune diseases are associated with significant morbidity and mortality, afflicting about 5% of the US population. They encompass a wide range of disorders that affect all organs of the human body and have a predilection for women. In the past, autoimmune pathogenesis was not thought to be a major mechanism for cardiovascular disorders, and potential relationships remain understudied. However, accumulating evidence suggests that a number of vascular and cardiac conditions are autoimmune mediated. Recent studies indicate that autoantibodies play an important role in the development of cardiac arrhythmias, including atrial fibrillation, modulation of autonomic influences on heart rate and rhythm, conduction system abnormalities, and ventricular arrhythmias. This article will review the current evidence for the role of autoantibodies in the development of cardiac arrhythmias. |
15,030 | Ischemic ventricular arrhythmias: experimental models and their clinical relevance. | In the United States, sudden cardiac death accounts for an estimated 300,000 to 350,000 cases each year, with 80,000 presenting as the first manifestation of a preexisting, sometimes unrecognized, coronary artery disease. Acute myocardial infarction (AMI)-induced ventricular fibrillation frequently occurs without warning, often leading to death within minutes in patients who do not receive prompt medical attention. Identification of patients at risk for AMI-induced lethal ventricular arrhythmias remains an unmet medical need. Recent studies suggest that a genetic predisposition may significantly contribute to the vulnerability of the ischemic myocardium to ventricular tachycardia/ventricular fibrillation. Numerous experimental models have been developed for the purpose of advancing our understanding of the mechanisms responsible for the development of cardiac arrhythmias in the setting of ischemia and with the aim of identifying antiarrhythmic therapies that could be of clinical benefit. While our understanding of the mechanisms underlying AMI-induced ventricular arrhythmias is coming into better focus, the risk stratification of patients with AMI remains a major challenge. This review briefly discusses our current state of knowledge regarding the mechanisms of ischemic ventricular arrhythmias and their temporal distribution as revealed by available experimental models, how these correlate with the clinical syndromes, as well as prospective prophylactic therapies for the prevention and treatment of ischemia-induced life-threatening arrhythmias. |
15,031 | Can death unrelated to secondary causes be predicted in intubated comatose tricyclic antidepressant-poisoned patients? | It has been stated that the level of consciousness at presentation is the most sensitive clinical predictor of dysrhythmia and seizure in patients with tricyclic antidepressant (TCA) overdose.</AbstractText>To assess the prognostic value of the clinical characteristics and electrocardiographic (ECG) parameters in intubated comatose TCA-poisoned patients for predicting death.</AbstractText>In this retrospective, unmatched case-control study--conducted in Loghman-Hakim Poison Hospital in Tehran, Iran, between March 2005 and September 2010--the medical charts of 25 non-survived (cases) and 72 survived (controls) TCA-poisoned patients, initially presenting with deep coma (GCS ≤ 8) and being intubated before or after hospital presentation, were evaluated. Exclusion criteria were multiple drug ingestion, head trauma, underlying heart diseases, history of previous convulsive disorders, and late death. Age, gender, specific TCA ingested, manner of poisoning, time between ingestion and presentation, occurrence of seizure, and the patient's initial emergency department vital signs were extracted and recorded. The first 12-lead ECG performed after hospital presentation was evaluated.</AbstractText>Ten cases and none of the controls had advanced ECG changes (ventricular fibrillation, torsades des pointes, or asystole). Using a logistic regression model, from variables with a statistically significant difference between the two groups (i.e. ingestion of nortriptyline and amitriptyline, pulse and respiratory rates at presentation, occurrence of seizure [before and after presentation or both], height of R wave in lead aVR, T40-ms frontal plane QRS axis, and occurrence of premature ventricular contraction), only seizure after hospital presentation reached significance regarding prediction of death (OR = 40.88; 95% CI = 9.93-168.39; p < 0.001).</AbstractText>Neither ECG parameters nor clinical characteristics of the intubated comatose patients with TCA toxicity predicts death in patients who had not died due to the secondary causes. The only prognostic indicator of death in such patients is seizure after hospital presentation.</AbstractText> |
15,032 | Effects of quinidine on the action potential duration restitution property in the right ventricular outflow tract in patients with brugada syndrome. | On a cellular level, Brugada syndrome has been attributed to a deep phase 1 notch and subsequent shallow and prolonged repolarization in the right ventricular outflow tract (RVOT). A sodium channel mutation that leads to early inactivation of the late sodium current has been identified in some patients. Thus, drugs that inhibit the transient outward current (I(to)) responsible for the phase 1 notch and/or enhance the late sodium current might suppress arrhythmic events in patients with Brugada syndrome. The effects of quinidine gluconate, a potent inhibitor of I(to), on RVOT action potential duration (APD) restitution kinetics in patients with Brugada syndrome were evaluated.</AbstractText>Programmed ventricular stimulation was performed in 9 Brugada syndrome patients by delivering up to 3 extrastimuli from the right ventricular apex and RVOT. RVOT monophasic action potentials (MAPs) were recorded before and after intravenous administration of quinidine (n=6) or ibutilide (n=3). All patients had inducible ventricular fibrillation (VF) before drug administration. Both quinidine and ibutilide increased steady-state and minimum RVOT MAP duration during programmed stimulation. Quinidine decreased the maximum slope of the RVOT APD restitution curve and VF could not be induced after administration of quinidine in 5 of the 6 patients.</AbstractText>Quinidine appears to suppress the induction of VF by increasing RVOT MAP duration and decreasing the maximum slope of the restitution curve.</AbstractText> |
15,033 | Prevalence of J-point elevation in sudden arrhythmic death syndrome families. | The purpose of this study was to assess the prevalence of J-point elevation among the relatives of sudden arrhythmic death syndrome (SADS) probands.</AbstractText>J-point elevation is now known to be associated with idiopathic ventricular fibrillation. We hypothesized that this early repolarization phenomenon is an inherited trait responsible for a proportion of otherwise unexplained SADS cases.</AbstractText>Families of SADS probands were evaluated in an inherited arrhythmia clinic. Twelve-lead electrocardiograms were analyzed for J-point elevation defined as >0.1 mV from baseline present in 2 or more of the inferior (II, III, and aVF) or lateral (1, aVL, V(4) to V(6)) leads. Electrocardiographic data were compared with those of 359 controls of a similar age, sex, and ethnic distribution.</AbstractText>A total of 363 first-degree relatives from 144 families were evaluated. J-point elevation in the inferolateral leads was present in 23% of relatives and 11% of control subjects (odds ratio: 2.54, 95% confidence interval: 1.66 to 3.90; p < 0.001).</AbstractText>J-point elevation is more prevalent in the relatives of SADS probands than in controls. This indicates that early repolarization is an important potentially inheritable pro-arrhythmic trait or marker of pro-arrhythmia in SADS.</AbstractText>Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,034 | Atrial electrical and structural changes associated with longstanding hypertension in humans: implications for the substrate for atrial fibrillation. |  </AbstractText>Hypertension (HT) is the most common modifiable risk factor for atrial fibrillation (AF), yet little is known of the atrial effects of chronic HT in humans. We aimed to characterize the electrophysiologic (EP) and electroanatomic (EA) remodeling of the right atrium (RA) in patients with chronically treated systemic HT and left ventricular hypertrophy (LVH) without a history of AF.</AbstractText>Twenty patients with (systolic BP 145 ± 10 mmHg) and without (BP 119 ± 11 mmHg, P < 0.01) systemic HT underwent detailed conventional EP and EA voltage and activation mapping. We measured RA refractoriness at the coronary sinus and high septum at cycle lengths (CLs) 600 and 450 ms, and RA conduction velocities, activation times, and voltages at a global and regional level at CLs 600 ms and 300 ms. HT was associated with slowing of global (73 ± 17 cm/s vs 96 ± 12 cm/s in controls, P < 0.01) and regional conduction velocity particularly in the posterior RA (70 ± 17 cm/s vs 96 ± 12 cm/s in controls, P < 0.01) at the crista terminalis (fractionation and double potentials in HT 72%± 4 vs 43%± 23 in controls, P = 0.04). Mean RA voltage was similar between the 2 groups, however HT was associated with an increase in areas of low voltage (<0.5 mV; HT 13% vs controls 9%, P = 0.04). Sustained AF was induced in 30% HT patients and no controls.</AbstractText>Chronically treated systemic HT with LVH is accompanied by atrial remodeling characterized by: (i) global conduction slowing, (ii) regional conduction delay particularly at the crista terminalis, and (iii) increased AF inducibility. These changes may in part be responsible for the increased propensity to AF associated with systemic HT.</AbstractText>© 2011 Wiley Periodicals, Inc.</CopyrightInformation> |
15,035 | Outcomes of cardiac catheterization and percutaneous coronary intervention for in-hospital ventricular tachycardia or fibrillation cardiac arrest. | This study examined outcomes of patients with sudden cardiac death attributable to primary ventricular tachycardia (VT) or ventricular fibrillation (VF) that underwent cardiac catheterization with or without percutaneous coronary intervention (PCI).</AbstractText>The decision to perform cardiac catheterization and PCI in resuscitated patients with sudden cardiac death remains controversial. Prior data suggest a potential benefit from percutaneous revascularization.</AbstractText>All patients with an in-hospital pulseless VT or VF cardiac arrest from August 2002 to February 2008 who underwent cardiac catheterization were included. Retrospective chart review was performed to obtain clinical, neurologic, and angiographic data. Primary endpoints were all-cause mortality and neurologic outcome.</AbstractText>Two thousand and thirty-four patients had in-hospital cardiac arrest, of these 116 had pulseless VT or VF and were resuscitated and 93 (80%) underwent coronary angiography. The median time to follow-up was 1.3 years (IQR: 0.5-2.9 years). Obstructive coronary artery disease (CAD) was observed in 74 (79%) individuals, of whom 37 underwent PCI. Thirty-five patients with obstructive CAD (47%) died compared to 41% with nonobstructive CAD. In unadjusted and multivariable adjusted analysis PCI was not associated with lower mortality (adjusted hazard ratio: 1.54, 95% CI, 0.79-3.02, P = 0.20). No significant differences were noted in neurologic status at discharge (P = 0.49).</AbstractText>In this study, an aggressive revascularization strategy with PCI did not confer a survival advantage nor was it associated with improved neurologic outcomes. There was no suggestion of harm with PCI and further studies are necessary to identify potential subgroups that may benefit from revascularization.</AbstractText>Copyright © 2011 Wiley Periodicals, Inc.</CopyrightInformation> |
15,036 | Atrial ectopic tachycardia in a patient with marfan syndrome. | The fibrillin defect central to Marfan syndrome is believed to affect myocardial conduction and predispose affected patients to various arrhythmias, including ventricular tachycardia, atrial fibrillation, and atrioventricular nodal reentry tachycardia. Here we describe an adult Marfan patient with atrial ectopic tachycardia. To our knowledge, this is the first reported case of atrial ectopic tachycardia in the setting of Marfan syndrome. |
15,037 | The phosphatonin fibroblast growth factor 23 links calcium-phosphate metabolism with left-ventricular dysfunction and atrial fibrillation. | High serum phosphate is linked to cardiovascular morbidity and mortality in the general population. Fibroblast growth factor 23 (FGF-23) is a critical phosphate regulating hormone, potentially reflecting phosphate load better than a single serum phosphate measurement. Recent pioneering echocardiographic studies associated FGF-23 with left-ventricular morphology. However, the association between FGF-23 and left-ventricular function is unknown, prompting us to investigate this relationship in our HOM SWEET HOMe study.</AbstractText>We studied the association between C-terminal FGF-23, coronary artery disease, and left-ventricular function in 885 subjects undergoing elective coronary angiography. Left-ventricular function was assessed with ventriculography. More, pro-brain natriuretic peptide (pro-BNP) plasma levels were measured. The presence of left-ventricular hypertrophy and atrial fibrillation was assessed by electrocardiography. Patients with an ejection fraction <40% had significantly higher FGF-23 levels compared with patients with the ejection fraction >40% (P< 0.001). In multivariable regression analysis, the observed relationship between FGF-23 and left-ventricular function remained significant after adjustment for estimated glomerular filtration rate, presence of left-ventricular hypertrophy, and other confounding variables. In accordance, FGF-23 significantly correlated with pro-BNP plasma levels (r = 0.31; P< 0.001). Prevalent atrial fibrillation was associated with elevated FGF-23 levels, while the presence of coronary artery disease was not.</AbstractText>Fibroblast growth factor 23 levels are associated with left-ventricular function and atrial fibrillation even in the absence of renal function impairment. Of note, these cross-sectional data cannot prove causality; therefore, future studies will have to discern whether FGF-23 exerts a direct untoward effect on the myocardium, or rather represents an 'innocent bystander' which reflects a high phosphate burden.</AbstractText> |
15,038 | Assessment of sotalol prescribing in a community hospital: opportunities for clinical pharmacist involvement. | Due to risk of serious adverse drug events (ADEs) sotalol use is limited in renal insufficiency and heart failure. To reduce potential life-threatening ADEs, medication safety initiatives that ensure appropriate dosing of sotalol are necessary. Pharmacist-managed renal dosing assessment programmes ensure appropriate dosing of renally eliminated medications. A prospective medication safety evaluation was conducted to assess the need to include sotalol in an existing renal dosing assessment programme as well as the impact of clinical pharmacist assessment on sotalol prescribing.</AbstractText>Patients in a 736-bed community hospital, receiving sotalol during a 6-week period, were prospectively evaluated. Information was collected on indication, dosing, concomitant disease states and medications, renal function, QTc length, symptoms of toxicity and readmissions. Pharmacist recommendations were made when necessary and were followed to determine acceptance rate and patient outcomes.</AbstractText>Thirty-six patients were prescribed sotalol for atrial tachyarrhythmias. Thirty-two (89%) were dosed inappropriately with respect to renal function. Twenty (56%) had left-ventricular dysfunction as defined by an ejection fraction of ≤ 40%. At time of initial assessment, 15 (42%) were exhibiting signs of potential sotalol toxicity. Pharmacists provided recommendations regarding discontinuation or dosage adjustment on 32 patients with a 38% full and a 12% partial acceptance rate. All-cause readmission rates for patients receiving appropriate therapy, including those after pharmacist recommendations were accepted (Group A; n=16), were compared to those remaining on inappropriate therapy (Group B; n=20). Readmission rates within 6 months differed between groups (31% for Group A, 55% for Group B; P=0.095, odds ratio 3.7).</AbstractText>This medication safety evaluation suggests the need for pharmacist assessment in patients receiving sotalol. Dosage adjustment or avoidance in patients with renal insufficiency, heart failure and other relative contraindications is often necessary to avoid toxicity. Sotalol was inappropriately prescribed in the majority of patients secondary to renal insufficiency. Based on this evaluation, it was recommended to add sotalol to the institution's pharmacist-managed renal dosing adjustment programme. Ensuring clinical pharmacist assessment when sotalol is prescribed can help reduce potential life-threatening ADEs and hospital readmissions.</AbstractText>© 2011 The Authors. IJPP © 2011 Royal Pharmaceutical Society.</CopyrightInformation> |
15,039 | Angiotensin II does not acutely regulate conduction velocity in rat atrial tissue. | Atrial angiotensin II (Ang II) levels are increased in atrial fibrillation and are believed to be important in the pathogenesis of atrial arrhythmias. Ang II reduces intercellular coupling by inhibiting gap junctions (connexins) and may thereby increase the risk of reentry arrhythmia. The aim of the current study was to investigate the acute effect of Ang II on conduction velocity (CV) in atrial tissue from normal and chronically infarcted rats.</AbstractText>Contractile force was measured and CV was determined from the conduction time between electrodes placed on the tissue preparation. Expression of AT1a and AT1b receptors was examined by real-time PCR.</AbstractText>Acute stimulation with Ang II did not affect CV in tissue from auricle or atrial free wall. A transient 6.5 ± 3.6% increase in resting tension was observed in atrial free wall preparations, indicating that receptors are present and functional in the free wall preparation. The difference between free wall and auricle was probably not caused by differences in receptor expression since equal amounts of AT1 mRNA were present. To test if myocardial infarction (MI) sensitizes the atrium to Ang II, free atrial wall from rats subjected to 4-5 weeks ventricular MI was examined. Although CV was significantly reduced by MI, no effect on CV of Ang II was seen.</AbstractText>Ang II does not acutely regulate CV in tissue preparations from the free wall of the left atria or the left auricle. Although ventricular MI reduces CV, this does not sensitize the atria to Ang II.</AbstractText> |
15,040 | The value of a family history of sudden death in patients with diagnostic type I Brugada ECG pattern. | We sought to investigate the value of a family history of sudden death (SD) in Brugada syndrome (BS).</AbstractText>Two hundred and eighty consecutive patients (mean age: 41 ± 18 years, 168 males) with diagnostic type I Brugada ECG pattern were included. Sudden death occurred in 69 (43%) of 157 families. One hundred and ten SDs were analysed. During follow-up VF (ventricular fibrillation) or SD-free survival rate was not different between patients with or without a family history of SD of a first-degree relative, between patients with or without a family history of multiple SD of a first-degree relative at any age and between patients with or without a family history of SD in first-degree relatives ≤35 years. One patient had family history of SD of two first-degree relative ≤35 years with arrhythmic event during follow-up. In univariate analysis male gender (P = 0.01), aborted SD (P < 0.001), syncope (P = 0.04), spontaneous type I ECG (P < 0.001), and inducibility during electrophysiological (EP) study (P < 0.001) were associated with worse prognosis. The absence of syncope, aborted SD, spontaneous type I ECG, and inducibility during EP study was associated with a significantly better prognosis (P < 0.001).</AbstractText>Family history of SD is not predictive for future arrhythmic events even if considering only SD in first-degree relatives or SD in first-degree relatives at a young age. The absence of syncope, aborted SD, spontaneous type I ECG, and inducibility during EP study is associated with a good five-year prognosis.</AbstractText> |
15,041 | The impact of body mass index on the efficacy and safety of catheter ablation of atrial fibrillation. | Obesity is a well established risk factor for atrial fibrillation (AF) development. Our purpose was to determine the impact of body mass index (BMI) on the safety and efficacy of radiofrequency catheter ablation of AF.</AbstractText>Two hundred and twenty-six consecutive patients with symptomatic, drug-refractory paroxysmal (59.3%) and persistent (40.7%) AF underwent wide circumferential electrical pulmonary vein isolation. Patients were classified according to BMI as normal (<25kg/m(2)); overweight (25 to 29.9kg/m(2)); and obese (≥30kg/m(2)).</AbstractText>Patients with high BMI were younger and displayed a higher rate of hypertension, increased left atrial diameter, increased left ventricular end-diastolic and end-systolic diameters, and increased levels of several conventional markers of inflammation and oxidative stress including white blood cell count, fibrinogen, uric acid, alanine aminotransferase, and gamma-glutamyltransferase (p<0.05). After a mean follow-up period of 432.32±306.09days from the index procedure, AF recurrence rate was 34.9% for normal weight, 46.2% for overweight, and 46.2% for obese patients (p: 0.258). Subjects classified above the 50th percentile for BMI displayed a trend toward a higher AF recurrence rate (p: 0.08). In univariate Cox regression survival analysis, BMI was not predictive of AF recurrence. Radiation exposure was significantly higher in overweight and obese patients in relation to normal weight patients (p: 0.003). No significant differences regarding major complications were observed among BMI groups.</AbstractText>In this study population, BMI was not an independent predictor of AF recurrence following left atrial catheter ablation.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
15,042 | Biomarkers of structural remodelling and endothelial dysfunction for prediction of cardiovascular events or death in patients with atrial fibrillation. | Atrial fibrillation (AF) is associated not only with inflammation but also with structural remodelling and altered endothelial activation which may contribute to clot formation, embolization and mortality. We aimed to determine the predictive value of single-time biomarker analysis for prediction of outcome in patients with AF.</AbstractText>We conducted a prospective study to evaluate if biomarkers of structural, electrical or endothelial remodelling are predictive of cardiovascular events (composite primary endpoint of myocardial infarction, stroke, peripheral embolism or death). Secondary endpoint was all-cause mortality. Patients with any type of AF and without active inflammatory conditions were eligible. Plasma samples were collected for ELISA analysis of biomarkers (inflammation [hsCRP, sCD40L], structural [MMP-2] and endothelial remodelling [vWF, sVCAM-1]) at enrolment. Patients (n = 278) were followed for 28 ± 12 (median 32) months. Eighty-eight individuals (32%) experienced a primary outcome event, including 8 (2.9%) with myocardial infarction, 13 (4.8%) with stroke and 4 (1.5%) with peripheral embolism. Predictors of the primary endpoint were age >75 years, CHADS(2)-score >2, LVEF <35%, diabetes, presence of an ICD/pacemaker, elevated vWF, sVCAM-1 and MMP-2 levels. On multivariate regression analysis, only age >75 years, sVCAM-1 and MMP-2 levels remained independently associated with the endpoint. There were 75 deaths during follow-up. Age >75 years, reduced LVEF, elevated sVCAM-1 and MMP-2 levels were predictors of all-cause mortality.</AbstractText>In this cohort of AF patients, old age, elevated sVCAM-1 and MMP-2 levels were associated with cardiovascular events. Our data indicate that single-time biomarker assessment may be a useful tool to improve risk stratification schemes.</AbstractText> |
15,043 | Sodium nitroprusside-enhanced cardiopulmonary resuscitation improves resuscitation rates after prolonged untreated cardiac arrest in two porcine models. | Sodium nitroprusside-enhanced cardiopulmonary resuscitation consists of active compression-decompression, an impedance threshold device, abdominal binding, and large intravenous doses of sodium nitroprusside. We hypothesize that sodium nitroprusside-enhanced cardiopulmonary resuscitation will significantly increase carotid blood flow and return of spontaneous circulation compared to standard cardiopulmonary resuscitation after prolonged ventricular fibrillation and pulseless electrical activity cardiac arrest.</AbstractText>Prospective randomized animal study.</AbstractText>Hennepin County Medical Center Animal Laboratory.</AbstractText>Forty Yorkshire female farm-bred pigs weighing 32 ± 2 kg.</AbstractText>In protocol A, 24 isoflurane-anesthetized pigs underwent 15 mins of untreated ventricular fibrillation and were subsequently randomized to receive standard cardiopulmonary resuscitation (n = 6), active compression-decompression cardiopulmonary resuscitation + impedance threshold device (n = 6), or sodium nitroprusside-enhanced cardiopulmonary resuscitation (n = 12) for up to 15 mins. First defibrillation was attempted at minute 6 of cardiopulmonary resuscitation. In protocol B, a separate group of 16 pigs underwent 10 mins of untreated ventricular fibrillation followed by 3 mins of chest compression only cardiopulmonary resuscitation followed by countershock-induced pulseless electrical activity, after which animals were randomized to standard cardiopulmonary resuscitation (n = 8) or sodium nitroprusside-enhanced cardiopulmonary resuscitation (n = 8).</AbstractText>The primary end point was carotid blood flow during cardiopulmonary resuscitation and return of spontaneous circulation. Secondary end points included end-tidal CO2 as well as coronary and cerebral perfusion pressure. After prolonged untreated ventricular fibrillation, sodium nitroprusside-enhanced cardiopulmonary resuscitation demonstrated superior rates of return of spontaneous circulation when compared to standard cardiopulmonary resuscitation and active compression-decompression cardiopulmonary resuscitation + impedance threshold device (12 of 12, 0 of 6, and 0 of 6 respectively, p < .01). In animals with pulseless electrical activity, sodium nitroprusside-enhanced cardiopulmonary resuscitation increased return of spontaneous circulation rates when compared to standard cardiopulmonary resuscitation. In both groups, carotid blood flow, coronary perfusion pressure, cerebral perfusion pressure, and end-tidal CO2 were increased with sodium nitroprusside-enhanced cardiopulmonary resuscitation.</AbstractText>In pigs, sodium nitroprusside-enhanced cardiopulmonary resuscitation significantly increased return of spontaneous circulation rates, as well as carotid blood flow and end-tidal CO2, when compared to standard cardiopulmonary resuscitation or active compression-decompression cardiopulmonary resuscitation + impedance threshold device.</AbstractText> |
15,044 | Hypothermia after cardiac arrest: beneficial, but slow to be adopted. | Survivors of cardiac arrest due to ventricular tachycardia or ventricular fibrillation have improved neurologic outcomes if they are cooled to a core body temperature of 32°C to 34°C for 24 hours as soon as possible after reaching the hospital. |
15,045 | Update in hospital medicine: studies likely to affect inpatient practice in 2011. | Dabigatran (Pradaxa) will likely start to replace warfarin (Coumadin) both to prevent stroke in patients with atrial fibrillation and to prevent recurrent venous thromboembolism. Using a checklist during insertion of central venous catheters can decrease the rate of catheter-related bloodstream infections in the intensive care unit. The overall survival rate of patients who undergo cardiopulmonary resuscitation in the intensive care unit is approximately 16%; the rate is lower in patients who are receiving pressor drugs and higher in those with ventricular tachycardia or ventricular fibrillation. Patients lacking follow-up with a primary care physician within 30 days of discharge are at high risk of readmission and have a trend for longer length of hospital stay. Preoperative stress testing for patients undergoing noncardiac surgery should be done selectively, i.e., in patients at high risk. |
15,046 | Remodeling of atrial ATP-sensitive K⁺ channels in a model of salt-induced elevated blood pressure. | Hypertension is associated with the development of atrial fibrillation; however, the electrophysiological consequences of this condition remain poorly understood. ATP-sensitive K(+) (K(ATP)) channels, which contribute to ventricular arrhythmias, are also expressed in the atria. We hypothesized that salt-induced elevated blood pressure (BP) leads to atrial K(ATP) channel activation and increased arrhythmia inducibility. Elevated BP was induced in mice with a high-salt diet (HS) for 4 wk. High-resolution optical mapping was used to measure atrial arrhythmia inducibility, effective refractory period (ERP), and action potential duration at 90% repolarization (APD(90)). Excised patch clamping was performed to quantify K(ATP) channel properties and density. K(ATP) channel protein expression was also evaluated. Atrial arrhythmia inducibility was 22% higher in HS hearts compared with control hearts. ERP and APD(90) were significantly shorter in the right atrial appendage and left atrial appendage of HS hearts compared with control hearts. Perfusion with 1 μM glibenclamide or 300 μM tolbutamide significantly decreased arrhythmia inducibility and prolonged APD(90) in HS hearts compared with untreated HS hearts. K(ATP) channel density was 156% higher in myocytes isolated from HS animals compared with control animals. Sulfonylurea receptor 1 protein expression was increased in the left atrial appendage and right atrial appendage of HS animals (415% and 372% of NS animals, respectively). In conclusion, K(ATP) channel activation provides a mechanistic link between salt-induced elevated BP and increased atrial arrhythmia inducibility. The findings of this study have important implications for the treatment and prevention of atrial arrhythmias in the setting of hypertensive heart disease and may lead to new therapeutic approaches. |
15,047 | Left atrial 'sludge' during vagally mediated pause triggered by pulmonary vein antral ablation. | We report a case of a patient with long-standing persistent atrial fibrillation (AF) who had rapid formation of spontaneous echo-contrast in the left atrium during pulmonary vein antrum isolation set off by a vagally mediated pause despite standard anticoagulation protocol. Spontaneous echo contrast resolved with ventricular pacing, representing visual evidence for dependence of some AF patients with poor atrial transport function on ventricular emptying with potential greater risk of thromboembolism related to a long ventricular pause. |
15,048 | Safety of nerve conduction studies in patients with implantable cardioverter-defibrillators. | A patient with an implantable cardioverter-defibrillator (ICD) may suffer from neuromuscular disorders and may need to undergo a nerve conduction study (NCS). However, a NCS may be a source of electromagnetic interference (EMI). The aim of the present study was to investigate whether the interference from NCS used in a standardised test protocol affects ICD function.</AbstractText>Twenty patients (19 males; mean age of 59.8±9.9 years) with implantable ICDs (eight with integrated and 12 with true bipolar leads), treated with amiodarone and with symptoms suggesting neuropathy were included. NCS were conducted using repetitive stimulation with frequency of 2 Hz and single, rectangular pulses of intensity up to 100 mA. Stimulation was performed in standard sites including proximal sites in the arm.</AbstractText>The impulses generated NCS were not detected by the ICD, irrespective of the site, rate or stimulus intensity.</AbstractText>Standardised test protocol for an NCS is safe in patients with an ICD regardless of the leads type.</AbstractText>Current guidelines which limitate the NCS in patients with ICD may be the subject of revision.</AbstractText>Copyright © 2011 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
15,049 | Usefulness of left ventricular diastolic dysfunction assessed by pulsed tissue Doppler imaging as a predictor of atrial fibrillation recurrence after successful electrical cardioversion. | The impact of left ventricular (LV) diastolic dysfunction on risk of atrial fibrillation (AF) recurrence is still unknown. The aim of this study was to assess the role of LV diastolic dysfunction in predicting AF recurrence after successful electrical cardioversion in patients with nonvalvular AF. In 51 patients with a first episode of nonvalvular AF undergoing successful electrical cardioversion, tissue Doppler echocardiography was performed to measure peak early diastolic mitral annulus velocity (E(m)) and the ratio of mitral inflow to mitral annulus velocity at end-diastole (E/E(m)). Clinical end points were recurrent persistent AF at 2-week follow-up (early AF recurrence [ERAF]) and at 1-year follow-up (including ERAF and late AF recurrence). Seventeen patients showed evidence of ERAF, whereas late AF recurrence occurred in another 5 patients. In time-independent analysis E/E(m) (odds ratio [OR] 1.746, p = 0.0084) and indexed LV end-systolic volume (OR 1.083, p = 0.040) were independent predictors of ERAF. Based on a logistic model risk of ERAF was 25% for an E/E(m) of 5.6 but increased to 50% for an E/E(m) of 8.1 and to 75% for an E/E(m) of 10.5. In time-dependent analysis E/E(m) emerged as the only predictor of ERAF (OR 1.757, p = 0.0078). E/E(m) also independently predicted risk of recurrence at 1 year in time-independent (OR 1.757, p = 0.0078) and time-dependent (OR 1.319, p = 0.0003) analyses. In conclusion LV diastolic dysfunction independently predicts AF recurrence in patients with nonvalvular AF undergoing successful electrical cardioversion. |
15,050 | The effect of heart rhythm on patient radiation dose with dual-source cardiac computed tomography. | To lower the radiation exposure associated with cardiac CT, it is essential to identify all factors that influence radiation dose.</AbstractText>We explored the effect of heart rhythm during scan acquisition on radiation dose with a 64-slice dual-source cardiac CT.</AbstractText>Patient and scan data were collected prospectively in 302 consecutive patients referred for a clinical dual-source cardiac CT. Electrocardiograms recorded during acquisition were interpreted by a cardiologist and categorized as (1) normal sinus rhythm (NSR), (2) premature atrial contraction (PAC) or premature ventricular contraction (PVC), or (3) atrial fibrillation or flutter.</AbstractText>Of the 302 patients, 227 (75.2%) were in NSR and had no ectopy, 55 (18.2%) had PAC/PVC, and 20 (6.6%) had atrial fibrillation or flutter during the scan. Patients with irregular rhythm (PAC/PVC and atrial fibrillation or flutter) were older than patients with regular rhythm (61.0 vs 54.8 years; P = 0.006). Patients with NSR had the lowest estimated radiation dose, followed by PAC/PVC and atrial fibrillation/flutter (9.4, 14.5, 20.9 mSv; P < 0.001). The difference remained significant after adjustments for differences in examination type, tube current and voltage, scan length, pitch, and use of tube current modulation (9.8, 14.1, 17.9 mSv; P < 0.001). No significant association was observed between heart rhythm and subjective image quality although scans with regular rhythm and no ectopy had higher signal-to-noise and contrast-to-noise ratios (P < 0.01).</AbstractText>Compared to patients with NSR, patients with atrial fibrillation/flutter had the highest radiation exposure, followed by those with PAC/PVC. Even after adjustment for factors associated with radiation exposure, a significant difference in radiation dose persisted. These findings can be used to identify patients who are more likely to receive higher radiation dose when undergoing cardiac CT and to develop future more-efficient scanner algorithms for use in patients with arrhythmias.</AbstractText>Copyright © 2011 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,051 | High-frequency powers hidden within QRS complex as an additional predictor of lethal ventricular arrhythmias to ventricular late potential in post-myocardial infarction patients. | Ventricular late potentials (VLPs) have been known to be a predictor of lethal ventricular arrhythmias (L-VAs); however, detection of other arrhythmogenic signals within the QRS complex remains obscure.</AbstractText>The aim of this study was to evaluate whether abnormal intra-QRS high-frequency powers (IQHFP) within the QRS complex become a new predictor of L-VAs in addition to VLPs.</AbstractText>Both 12-lead electrocardiograms (ECG) and VLPs were recorded from 142 subjects, including 37 patients without heart diseases, 97 patients post-myocardial infarction (MI), and 45 post-MI patients with L-VAs. Time-frequency analysis of ECG (leads V(1) or II) using wavelet transform with the Morlet function was performed. After the time-frequency powers were calculated, the ratios of the peak of signal power during the QRS complex in high-frequency bands against the peak power at 80 Hz (b/a ratio; P100, P150, P200, P250, or P300Hz/P80Hz) were measured. Abnormal IQHFP was defined when the b/a ratio exceeded the optimal cut-off values estimated by receiver-operator characteristic curves.</AbstractText>The combination of abnormal IQHFP appearing at 200, 250, and 300 Hz with positive VLPs increased the sensitivity for prediction of L-VAs from 53.3% by VLPs to 89.5%, and the negative predictive value from 74.7% by VLPs to 87.7%.</AbstractText>The combined use of VLPs and IQHFP hidden within the QRS complex improved the prediction of L-VAs in post-MI patients.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,052 | Double-valve Libman-Sacks endocarditis causing ventricular fibrillation cardiac arrest. | Libman-Sacks endocarditis is a well-known and rather common cardiac manifestation of systemic lupus erythematosus. Transesophageal and transthoracic echocardiography are the definitive imaging methods used to evaluate cardiac valvular involvement in this disease. Valvular masses (vegetations) and valvular thickening are 2 common morphologic echocardiographic patterns. Libman-Sacks lesions are typically characterized by single-valve involvement and their small size of 1 to 4 mm.Herein, we present the unusual case of a 22-year-old woman with newly diagnosed systemic lupus erythematosus who had large, sterile vegetations of Libman-Sacks endocarditis that involved the mitral and aortic valves. This compromised coronary blood flow and resulted in ventricular fibrillation cardiac arrest. The vegetations were surgically excised, and the patient's cardiac function recovered. We discuss the treatment of the patient and that of Libman-Sacks endocarditis. |
15,053 | In-treatment stroke volume predicts cardiovascular risk in hypertension. | To evaluate whether lower stroke volume during antihypertensive treatment is a predictor of cardiovascular events independent of left ventricular geometric pattern.</AbstractText>The association between left ventricular stroke volume and combined cardiovascular death, stroke and myocardial infarction, the prespecified primary study endpoint, was assessed in Cox regression analysis using data from baseline and annual follow-up visits in 855 patients during 4.8 years of randomized losartan-based or atenolol-based treatment in the Losartan Intervention For Endpoint reduction in hypertension (LIFE) echocardiography substudy.</AbstractText>During follow-up, a total of 91 primary endpoints occurred. At baseline, lower left ventricular stroke volume was associated with smaller body size, female sex, lower left ventricular mass and stress-corrected midwall shortening, higher relative wall thickness and total peripheral resistance, more concentric left ventricular geometry and impaired diastolic relaxation (all P < 0.01). Baseline stroke volume did not predict outcome. However, in time-varying multivariable Cox regression analysis, lower in-treatment left ventricular stroke volume indexed for height was associated with higher risk of cardiovascular events {hazard ratio 1.69 per 1 SD (6 ml/m) lower stroke volume [95% confidence interval (CI) 1.35-2.11], P < 0.001} independent of in-treatment left ventricular mass and concentric geometry and in a secondary model also independent of stress-corrected midwall shortening, impaired diastolic relaxation, heart rate, new-onset atrial fibrillation and study treatment [hazard ratio 1.46 per 1 SD (6 ml/m) lower stroke volume (95% CI 1.13-1.88)].</AbstractText>Assessment of in-treatment left ventricular stroke volume may reflect cardiac and vascular remodeling and impairment and, hence, adds information on cardiovascular risk in treated hypertensive patients beyond assessment of left ventricular structure alone.</AbstractText>NCT 00338260.</AbstractText> |
15,054 | Clinical characteristics and cardiovascular outcomes of hemodialysis patients with atrial fibrillation: a prospective follow-up study. | <AbstractText Label="BACKGROUND/AIMS" NlmCategory="OBJECTIVE">Among the cardiovascular complications in dialysis patients, atrial fibrillation (AF) is the most common arrhythmia. The purpose of this study was to clarify the characteristics and mortality of hemodialysis patients with AF, which are not completely elucidated.</AbstractText>The prevalence of AF in patients undergoing hemodialysis in our institutions was assessed. Patients with AF (AF group) and without AF (control group) were included in this study. Patients in the control group were matched for several important clinical risk factors. For further analysis, AF patients were divided into two groups on the basis of the type of AF (chronic AF (CAF) and paroxysmal AF (PAF) groups). These patients were evaluated for their clinical characteristics, laboratory data and echocardiographic parameters and prospectively followed up for 48 months.</AbstractText>Among 328 study patients, 30 had AF (9.1%). Left atrial diameter (LAD) and the left ventricular mass index were significantly greater in the AF group than in the control group. Furthermore, cardiovascular and all-cause mortality and cumulative incidence of cardiovascular events were significantly higher in the AF group than in the control group, and tended to be higher in the CAF group.</AbstractText>Our findings demonstrated that the prevalence of AF as 9.1% in hemodialysis patients, and that AF, especially CAF, were associated with high mortality.</AbstractText>Copyright © 2011 S. Karger AG, Basel.</CopyrightInformation> |
15,055 | Holter monitoring in syncope: diagnostic yield in octogenarians. | To determine the diagnostic yield of Holter monitoring in very old adults (≥80) with syncope.</AbstractText>A Holter study was considered diagnostic if the arrhythmia explained syncope (atrioventricular (AV) block, sinus node dysfunction, atrial fibrillation with severe bradycardia or tachycardia, supraventricular or ventricular tachycardia).</AbstractText>A tertiary care center in Switzerland over a period of 10 years.</AbstractText>Four hundred seventy-five Holter studies were performed in individuals aged 80 and older (median age 84, 65% female, mean left ventricular ejection fraction (LVEF) 0.56 ± 0.1%).</AbstractText>Fifty-three Holter studies (11%) were diagnostic. The detected arrhythmias were AV block (n=13), sinus node dysfunction (n=13), binodal disease (n=2), atrial fibrillation with slow or rapid ventricular response (n=21), ventricular tachycardia (n=3) and supraventricular tachycardia (n=1). Forty participants (8%) received a pacemaker, and one received an implantable cardioverter-defibrillator because of the results of Holter monitoring. The yield of Holter monitoring was significantly greater (all P<.01) in the presence of heart disease (17%) and low LVEF (22%), in men (17%) and in participants aged 90 and older (20%). Heart disease (odds ratio (OR)=3.2, 95% confidence interval (CI)=1.7-6.1), male sex (OR=2.1, 95% CI=1.1-3.8), and aged 90 and older (OR=2.4, 95% CI=1.2-5.1) remained independent predictors for a high diagnostic yield of Holter monitoring. Furthermore, Holter monitoring was helpful in excluding arrhythmias as a cause of syncope in an additional 10% of cases.</AbstractText>The diagnostic value of Holter monitoring in participants aged 80 and older with syncope was 11.2%. Its yield was higher in men and in the presence of structural heart disease and was 20% in individuals aged 90 and older.</AbstractText>© 2011, Copyright the Authors. Journal compilation © 2011, The American Geriatrics Society.</CopyrightInformation> |
15,056 | Cerebral air emboli with atrial-esophageal fistula following atrial fibrillation ablation: a case report and review. | Atrial-esophageal fistula (AEF) is a rare and early complication of radiofrequency ablation for medically refractory atrial fibrillation, but has devastating consequences when the diagnosis is delayed or difficult to make.</AbstractText>Single case in a neurosciences critical care center.</AbstractText>A 69-year-old man with significant cardiac and neurologic medical history who underwent atrial fibrillation ablation 50 days prior to admission to the neurocritical care unit presented with acute left-sided weakness and gram-positive bacterial sepsis. This is an exceptional case discussing the need for early detection of AEF presenting with sepsis, neurologic deficit along with complicated decision-making in the neurocritical care setting. His hospital course was complicated by acute stroke, left ventricular (LV) aneurysm with thrombus, gastrointestinal (GI) bleed discovered to be from left atrial esophageal fistula, and subsequent cerebral air emboli leading to death.</AbstractText>This is the most delayed presentation of AEF following atrial fibrillation ablation reported in the literature to date. We emphasize the need for awareness of this complication even after such an unexpected time-frame postprocedure as well as the unintended complications of cerebral air emboli following upper endoscopy.</AbstractText> |
15,057 | Cardioprotective activity of alcoholic extract of Tinospora cordifolia (Willd.) Miers in calcium chloride-induced cardiac arrhythmia in rats. | The present study investigated the antiarrhythmic activity of alcoholic extract of Tinospora cordifolia (T. cordifolia) in CaCl2 induced arrhythmia. CaCl2 (25 mg/kg) was administered by intravenous infusion (iv) to produce arrhythmia in rats. The animals were then treated with T. cordifolia extract (150, 250, and 450 mg/kg) and verapamil (5 mg/kg,iv). Lead II electrocardiogram was monitored. Plasma calcium, sodium and potassium levels were measured. In CaCl2 induced arrhythmia, heart rate was decreased by 41.10%, T. cordifolia at 150, 300, and 450 mg/kg decreased the heart rate by 26.30%, 29.16%, and 38.29%, respectively, and verapamil reduced the heart rate by 9.70% compared to the normal group. The PQRST waves were normalized and atrial and ventricular fibrillation was controlled in rats treated with verapamil and T. cordifolia. CaCl2 increased calcium and sodium levels and decreased potassium levels in blood. T. cordifolia dose-dependently decreased calcium and sodium levels and increased potassium levels. Hence, T. cordifolia can be used in antiarrhythmic clinical settings and beneficial in atrial and ventricular fibrillation and flutter and may be indicated in ventricular tachyarrhythmia. |
15,058 | Increase in survival and bystander CPR in out-of-hospital shockable arrhythmia: bystander CPR and female gender are predictors of improved outcome. Experiences from Sweden in an 18-year perspective. | In a national perspective, to describe survival among patients found in ventricular fibrillation or pulseless ventricular tachycardia witnessed by a bystander and with a presumed cardiac aetiology and answer two principal questions: (1) what are the changes over time? and (2) which are the factors of importance?</AbstractText>Observational register study.</AbstractText>Sweden.</AbstractText>All patients included in the Swedish Out of Hospital Cardiac Arrest Register between 1 January 1990 and 31 December 2009 who were found in bystander-witnessed ventricular fibrillation with a presumed cardiac aetiology. Interventions Bystander cardiopulmonary resuscitation (CPR) and defibrillation.</AbstractText>Survival to 1&emsp14;month.</AbstractText>In all, 7187 patients fulfilled the set criteria. Age, place of out-of-hospital cardiac arrest (OHCA) and gender did not change. Bystander CPR increased from 46% to 73%; 95% CI for OR 1.060 to 1.081 per year. The median delay from collapse to defibrillation increased from 12 min to 14 min (p for trend 0.0004). Early survival increased from 28% to 45% (95% CI 1.044 to 1.065) and survival to 1 month increased from 12% to 23% (95% CI 1.058 to 1.086). Strong predictors of early and late survival were a short interval from collapse to defibrillation, bystander CPR, female gender and OHCA outside the home.</AbstractText>In a long-term perspective in Sweden, survival to 1 month after ventricular fibrillation almost doubled. This was associated with a marked increase in bystander CPR. Strong predictors of outcome were a short delay to defibrillation, bystander CPR, female gender and place of collapse.</AbstractText> |
15,059 | Survival does not improve when therapeutic hypothermia is added to post-cardiac arrest care. | We investigated whether the use of therapeutic hypothermia improves the outcome after cardiac arrest (CA) under routine clinical conditions.</AbstractText>In a retrospective study, data of CA survivors treated from 2003 to 2010 were analysed. Of these, 143 patients were treated with hypothermia at 33 ± 0.5°C for 24h according to predefined inclusion criteria, while 67 who did not fulfil these criteria received comparable therapy without hypothermia.</AbstractText>210 patients were included, 143 in the hypothermia group (HG) and 67 in the normothermia group (NG). There was no significant difference in mortality between the groups; 69 (48.2%) in the HG died in the first four weeks, compared to 30 patients (44.8%) in the NG (p=0.659). Patients in the NG were older and more seriously ill, and CA occurred more often in-hospital. Binary logistic regression revealed ventricular fibrillation (p=0.044), NSE serum level < 33 ng ml⁻¹ (p<0.001), age (p=0.035) and witnessed cardiac arrest (p=0.043) as independent factors significantly improving survival after CA, whereas hypothermia was not (p=0.69). The target temperature was maintained for a significantly longer time (19.5h vs. 15.2h; p=0.003) in hypothermia patients with a favourable outcome than in those with an unfavourable outcome.</AbstractText>There was no improvement in survival rates when hypothermia was added to standard therapy in this case series, as compared to standard therapy alone. The time at target temperature may be of relevance. We need better evidence in order to expand the recommendations for hypothermia after CA.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
15,060 | Beta-blocker therapy for valvular disorders. | Valvular disorders are common, and result in a neurohormonal milieu similar to the heart failure state. Although valve surgery is the therapy of choice in symptomatic severe lesions, many patients do not receive surgery for a variety of reasons. Beta-blockers have a role in the management of many patients with valvular disorders, especially in the case of patients with mitral stenosis, where they reduce the transmitral gradient. They may also serve as life-saving therapy in pregnant women with pulmonary edema. Other uses of beta-blockers include the reduction of valve-related hemolysis, the prevention of atrial fibrillation, and the relief of dynamic left and right ventricular outflow tract obstruction. The prevention of aortic root dilation, potentially with beta-receptor blockade, may reduce the risk of aortic insufficiency in Marfan syndrome, and also in those with bicuspid aortic valves or following the Ross procedure. In this review, the potential role of beta-blockers is explored for the treatment of severe mitral and aortic regurgitation and asymptomatic severe aortic stenosis. |
15,061 | Impact of left ventricular ejection fraction on occurrence of ventricular events in defibrillator patients with coronary artery disease. | Primary preventive implantable cardioverter defibrillator (ICD) therapy is indicated in patients with coronary artery disease (CAD) and left ventricular ejection fraction (LVEF) of ≤ 35%, but some patients in the major trials had LVEF in the range of 30-35%. We hypothesized that these patients constitute a lower-risk population and might derive less benefit from ICD therapy.</AbstractText>In this retrospective study, patients with CAD in whom an ICD was implanted for primary prevention were studied. We determined the incidence of ICD therapies in two predefined LVEF cut-off groups (≤/>20%; ≤/>30%), predictors of ICD therapies, and overall mortality. A total of 536 patients were included: 88% male, age 63 ± 10 years, follow-up 30 ± 25 months. In all, 115 patients (22%) experienced appropriate ICD interventions; in 36% of them, the arrhythmia was treated with shock. Inappropriate therapy was delivered in 8%. Cumulative mortality at 5 years was 20%. Using our two cut-off levels, more ICD-therapies occurred in patients with poorer LVEF, but the difference was significant only with the cut-off value of ≤/>20%. Only 2 of 12 parameters were predictors of appropriate ICD therapy: age, odds ratio (OR) 1.047 (1.015-1.079) per year and QRS width, OR 1.014 per ms (1.004-1.024).</AbstractText>Refined risk stratification using different LVEF cut-off levels is not helpful in patients with CAD and LVEF ≤ 35%. Mortality was lower than in randomized trials in this real-world setting, probably due to better drug treatment at implant.</AbstractText> |
15,062 | Right ventricular lead positioning does not influence the benefits of cardiac resynchronization therapy in patients with heart failure and atrial fibrillation. | Little is known about the optimal right ventricular (RV) pacing site in cardiac resynchronization therapy (CRT). This study compares bi-ventricular pacing at the left ventricular (LV) free wall combined with two different RV stimulation sites: RV outflow tract (RVOT+LV) vs. RV-apex (RVA+LV).</AbstractText>Thirty-three patients (32 males) with chronic heart failure, NYHA class III-IV, optimal drug therapy, QRS-duration ≥150 ms, and chronic atrial fibrillation (AF) received CRT with two different RV leads, in the apex (RVA) or outflow tract (RVOT), together with an LV lead, all connected to a bi-ventricular pacemaker. Randomization to pacing in RVOT+LV or RVA+LV was made 1 month after implantation and cross-over to the alternate pacing configuration occurred after 3 months. The median age of patients was 69 ± 10 years, the mean QRS was 179 ± 23 ms, and 58% of patients had ischaemic heart disease. Seven patients had pacemaker rhythm at inclusion and 60% were treated with atrioventricular-junctional ablation before randomization. In the RVA+LV and RVOT+LV pacing modes, 67 and 63% (nonsignificant) responded symptomatically with a decrease of at least 10 points in the Minnesota Living with Heart Failure score. The secondary end-points (6-min walk test, peak oxygen uptake, N-Terminal fragment of B-type Natriuretic Peptide, and left ventricular ejection fraction) showed significant improvement between baseline and CRT, but not between RVOT+LV and RVA+LV.</AbstractText>In this randomized controlled study, the exact RV pacing site, either apex or outflow tract, did not influence the benefits of CRT in a group of patients with chronic heart failure and AF. ClinicalTrials.gov ID: NCT00457834.</AbstractText> |
15,063 | [Case of ventricular fibrillation in patients with brugada type electrocardiogram during surgery]. | We described a case of ventricular fibrillation in patients with Brugada type electrocardiogram (ECG) during surgery. A 63-year-old man underwent lung lobectomy under combined general and epidural anesthesia. His preoperative ECG showed Brugada type, but he was asymptomatic and did not have a family history of sudden death. Anesthesia was induced using propofol, vecuronium and fentanyl, and maintained using propofol and lidocaine via epidural catheter. One hour into operation, ventricular fibrillation developed. After cardiac compression in a few seconds, sinus rhythm was restored and blood pressure was elevated. When the wound was sutured, ventricular fibrillation occurred again. Defibrillation was attempted immediately and sinus rhythm was restored. We diagnosed coronary spastic angina after acetylcholine challenge test. Previous report describes that the incidence of vasospasm in Brugada type ECG cases is relatively higher than those with the normal ECG. In addition, ventricular fibrillation might be induced by local anesthetics because these agents were administrated 10 minutes before the few events and balance of autonomic nervous system was changed. We conclude that strict monitoring and immediate treatment for ventricular fibrillation are important for anesthetic management in asymptomatic patient with Brugada type ECG. |
15,064 | [Case of coronary vasospasm during lumbar discectomy in prone position]. | A 62-year-old man with hypertension was scheduled for discectomy at L4-5 in prone position. Anesthesia was induced with propofol 70 mg, fentanyl 0.75 mg and rocuronium 40 mg and maintained with sevoflurane 0.8-2.0% in oxygen 2 l x min(-1) and nitrous oxide 2 l x min(-1). Just before the end of surgery, ST elevation with hypotension on the ECG was observed for only a few seconds, followed by ventricular fibrillation (Vf). Immediately, lidocaine 50 mg, nitroglycerine 0.5 mg and methoxamine 6 mg were administered intravenously, and sinus rhythm and normal blood pressure returned from Vf within one minute. This case achieved a complete response to quick administration of the coronary vasodilator and antiarrhythmic agent, in this case whose coronary spasm was suspected on the basis of ST elevation in the first place. We have to be careful of various initiating factors for coronary spasm each time during anesthesia as it is difficult to assess its clinical risk, especially in prone position because actual coronary flow is much lower and cardiac resuscitation is difficult in a sudden cardiac complication. |
15,065 | Electrocardiographic changes in hospitalized patients with leptospirosis over a 10-year period. | The aim of this study was to investigate the incidence and type of ECG changes in patients with leptospirosis regardless of clinical evidence of cardiac involvement.</AbstractText><AbstractText Label="MATERIAL/METHODS" NlmCategory="METHODS">A total of 97 patients with serologically confirmed leptospirosis treated at the University Hospital for Infectious Diseases "Dr. Fran Mihaljević" in Zagreb, Croatia, were included in this retrospective study. A 12-lead resting ECG was routinely performed in the first 2 days after hospital admission. Thorough past and current medical history was obtained, and careful physical examination and laboratory tests were performed.</AbstractText>Abnormal ECG findings were found in 56 of 97 (58%) patients. Patients with abnormal ECG had significantly elevated values of bilirubin and alanine aminotransferase, lower values of potassium and lower number of platelets, as well as more frequently recorded abnormal chest x-ray. Non-specific ventricular repolarization disturbances were the most common abnormal ECG finding. Other recorded ECG abnormalities were sinus tachycardia, right branch conduction disturbances, low voltage of the QRS complex in standard limb leads, supraventricular and ventricular extrasystoles, intraventricular conduction disturbances, atrioventricular block first-degree and atrial fibrillation. Myopericarditis was identified in 4 patients. Regardless of ECG changes, the most commonly detected infection was with Leptospira interrogans serovar Australis, Leptospira interrogans serovar Saxkoebing and Leptospira kirschneri serovar Grippotyphosa.</AbstractText>The ECG abnormalities are common at the beginning of disease and are possibly caused by the direct effect of leptospires or are the non-specific result of a febrile infection and metabolic and electrolyte abnormalities. New studies are required for better understanding of the mechanism of ECG alterations in leptospirosis.</AbstractText> |
15,066 | The effects of acute amiodarone on short- and long-duration ventricular defibrillation threshold in canines. | Some studies have shown that the defibrillation threshold (DFT) differs between short-duration ventricular fibrillation (SDVF, <1 minute) and long-duration ventricular fibrillation (LDVF > 1 minute). The goal of this study is to evaluate the effects of acute intravenous amiodarone on SDVF-DFT and LDVF-DFT and its possible mechanism as well.</AbstractText>Twelve open-chest dogs were randomly divided into 2 groups (control group, normal saline, 10 mL·kg·h maintenance, n = 6; amiodarone group, loading dose 10 mg/kg over 10 minutes, maintenance dose 5 mg·kg·h, n = 6). VF was electrically induced and recorded with a 12 × 12 unipolar electrode plaque (2-mm spacing) sutured on the left ventricular epicardium and a plunge needle (6 unipolar electrode) inserted in the left ventricular apex. The DFTs of SDVF and LDVF were determined 20 seconds and 3 minutes after VF induction, respectively. Restitution was estimated from activation recovery intervals during pacing from the plaque and plunge needle electrodes. The activation rate was estimated by Fast Fourier Transform analysis of VF at same electrodes. The VF cycle length was defined as the reciprocal of the activation rate. The epicardial and transmural dispersion of the maximal slope of the restitution curve and VF cycle length of SDVF and LDVF were calculated, respectively.</AbstractText>: In controls, LDVF-DFT was higher than SDVF-DFT (645 ± 61 vs. 520 ± 63 V, P < 0.01). Amiodarone did not significantly alter SDVF-DFTs (496 ± 49 vs. 552 ± 69 V, P > 0.05) but decreased LDVF-DFT by 31% (P < 0.01). Compared with control, amiodarone significantly reduced the maximum slope of the restitution curve (1.12 ± 0.35 vs. 0.81 ± 0.25, P = 0.03) and its epicardial dispersion (0.32 ± 0.07 vs. 0.24 ± 0.04,coefficient of variation, P = 0.017). Amiodarone significantly increased the SDVF-CL (92 ± 8 vs. 99 ± 10 milliseconds, P < 0.01) and epicardial dispersion 0.14 ± 0.06 vs. 0.18 ± 0.05, P < 0.01. Amiodarone did not change the LDVF-CL (228 ± 12 vs. 226 ± 10 milliseconds, P > 0.05) or epicardial dispersion (0.17 ± 0.03 vs. 0.15 ± 0.02, P > 0.05) compared with control. However, the drug significantly decreased the transmural dispersion of LDVF-CL (68 ± 28 vs. 39 ± 14 milliseconds, P < 0.01) without changing the transmural dispersion of SDVF-CL (29 ± 22 vs. 32 ± 30 milliseconds, P > 0.05).</AbstractText>Acute amiodarone significantly decreased the LDVF-DFT. The decreased transmural dispersion of LDVF-CL by amiodarone might contribute to the decreased LDVF-DFT.</AbstractText> |
15,067 | Cholecystokinin octapeptide induces hypothermia and improves outcomes in a rat model of cardiopulmonary resuscitation. | To investigate the effects of cholecystokinin octapeptide on thermoregulation, postresuscitation myocardial function, neurologic outcome, and duration of survival in a rat model of cardiopulmonary resuscitation.</AbstractText>: Prospective, randomized, placebo-controlled experimental study.</AbstractText>University-affiliated animal research laboratory.</AbstractText>Ten male Sprague-Dawley rats.</AbstractText>Ventricular fibrillation was induced and untreated for 6 mins. Defibrillation was attempted after 8 mins of cardiopulmonary resuscitation. Animal temperature was adjusted to 37.0 °C with the aid of a heating lamp. At 30 mins after resuscitation, animals were randomized to receive an intravenous injection of either cholecystokinin octapeptide (200 μg/kg in 0.3 mL saline) or vehicle placebo (0.3 mL saline). The ambient temperature settings and that of the distance of the heating lamp from the animal remained the same in both groups throughout the entire experiment.</AbstractText>Body temperature, hemodynamic measurements, and postresuscitation myocardial function, including cardiac output, left ventricular ejection fraction, and myocardial performance index, were measured together with neurologic deficit scores and duration of survival.</AbstractText>After injection of cholecystokinin octapeptide, blood temperature decreased progressively from 37.0 °C to 34.8 °C 5 hrs after resuscitation and returned to 37.0 °C at 9 hrs after injection. In the control group, blood temperature was sustained at 37.0 °C ± 0.2 °C during the same period of observation. Myocardial and neurologic function and duration of survival were significantly better in the cholecystokinin octapeptide-treated animals when compared to the control group.</AbstractText>: In a rat model of cardiopulmonary resuscitation, cholecystokinin octapeptide induced mild hypothermia, attenuated postresuscitation myocardial dysfunction, and improved neurologic outcome and duration of survival.</AbstractText> |
15,068 | Mild therapeutic hypothermia is associated with favourable outcome in patients after cardiac arrest with non-shockable rhythms. | Mild therapeutic hypothermia (32-34°C) improves neurological recovery and reduces the risk of death in comatose survivors of cardiac arrest when the initial rhythm is ventricular fibrillation or pulseless ventricular tachycardia. The aim of the presented study was to investigate the effect of mild therapeutic hypothermia (32-34°C for 24h) on neurological outcome and mortality in patients who had been successfully resuscitated from non-ventricular fibrillation cardiac arrest.</AbstractText>In this retrospective cohort study we included cardiac arrest survivors of 18 years of age or older suffering a witnessed out-of-hospital cardiac arrest with asystole or pulseless electric activity as the first documented rhythm. Data were collected from 1992 to 2009. Main outcome measures were neurological outcome within six month and mortality after six months.</AbstractText>Three hundred and seventy-four patients were analysed. Hypothermia was induced in 135 patients. Patients who were treated with mild therapeutic hypothermia were more likely to have good neurological outcomes in comparison to patients who were not treated with hypothermia with an odds ratio of 1.84 (95% confidence interval: 1.08-3.13). In addition, the rate of mortality was significantly lower in the hypothermia group (odds ratio: 0.56; 95% confidence interval: 0.34-0.93).</AbstractText>Treatment with mild therapeutic hypothermia at a temperature of 32-34°C for 24h is associated with improved neurological outcome and a reduced risk of death following out-of-hospital cardiac arrest with non-shockable rhythms.</AbstractText>Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.</CopyrightInformation> |
15,069 | The prevalence of early repolarization in Wolff-Parkinson-White syndrome with a special reference to J waves and the effects of catheter ablation. | We determined the prevalence of J waves in the electrocardiograms (ECG) of 120 patients with Wolff-Parkinson-White syndrome in comparison with J-wave prevalence in a control group of 1936 men and women with comparable demographic and ECG characteristics and with normal atrioventricular conduction. J waves were present only during manifest preexcitation in 22 of 120 patients (18.3%), disappearing after catheter ablation and suggesting that J waves were associated with the presence of preexcitation. J waves were present in 19 (15.8%) of 120 patients only after ablation, apparently having been masked by early depolarization of the preexcited myocardial region, and in 22 patients (18.3%), J waves were not altered significantly by preexcitation. Thus, the overall J-wave prevalence was 52.5% (63/120) and, excluding those apparently due to preexcitation, 34.8% (41/120), both substantially higher than the prevalence (11.5%) in the control group (P < .001 for both). The patients with J waves appearing only during preexcitation were younger, predominantly females. The presence of J waves after ablation was associated with a history of atrial fibrillation and shorter ventricular effective refractory period. It is concluded that the prevalence of J waves is high in patients with Wolff-Parkinson-White syndrome and is influenced by manifest preexcitation. |
15,070 | Tissue Doppler atrial conduction times and electrocardiogram interlead P-wave durations with varying severity of obstructive sleep apnea. | Obstructive sleep apnea (OSA) has been reported to be associated with an increased risk of atrial fibrillation. The aim of this study was to investigate atrial electromechanical couplings in patients with OSA and the relationship between these parameters and P-wave dispersion (Pd).</AbstractText>One hundred twenty-six patients were enrolled in this study. All patients underwent polysomnographic examination. The apnea-hypopnea index (AHI) was defined as the number of apneas and hypopneas per hour of sleep. An AHI score of 5 or more was diagnosed as OSA, and an AHI score of less than 5 was diagnosed as OSA (-). Thirty-nine of the patients had an AHI score of less than 5 (group 1), 42 of the patients had AHI score between 5 and 30 (mild and moderate, group 2), 45 of the patients had an AHI score more than 30 (severe, group 3). Atrial electromechanical coupling (PA), intra-atrial, and interatrial electromechanical delay were measured with tissue Doppler imaging. P-wave dispersion was calculated from 12-lead electrocardiogram.</AbstractText>Maximum P-wave duration was higher in group 3 compared with groups 2 and 1 (126.0 ± 16.7 vs 111.0 ± 12.5 [P < .001] and 126.0 ± 16.7 vs 99.9 ± 10.0 [P < .001], respectively). Maximum P-wave duration was higher in group 2 than in group 1 (111.0 ± 12.5 vs 99.9 ± 10.0, P < .001). P-wave dispersion was higher in group 3 compared with groups 2 and 1 (50.9 ± 11.5 vs 37.0 ± 8.6 [P < .001] and 50.9 ± 11.5 vs 27.9 ± 6.8 [P < .001], respectively). P-wave dispersion was higher in group 2 than in group 1 (37.0 ± 8.6 vs 27.9 ± 6.8, P < .001). Minimum P-wave duration did not differ between the groups. Atrial PA at the left lateral mitral annulus (lateral PA), septal mitral annulus (septal PA), and right ventricular tricuspid annulus (RV PA) were significantly higher in group 3 than in group 2 (P < .001, P = .001, and P = .009, respectively). Lateral PA, septal PA, and RV PA were higher in group 2 compared with group 1 (P < .001, P = .003, and P = .009, respectively). Interatrial electromechanical delay (lateral PA - RV PA) was significantly longer in group 3 compared with groups 2 and 1 (33.6 ± 12.1 vs 22.4 ± 9.4 [P < .001] and 33.6 ± 12.1 vs 14.9 ± 9.2 [P < .001], respectively). Interatrial electromechanical delay was longer in group 2 than in group 1 (22.4 ± 9.4 vs 14.9 ± 9.2, P = .001). There was a positive correlation between AHI and Pd, lateral PA, septal PA, RV PA, interatrial electromechanical delay, and left-sided intra-atrial electromechanical delay.</AbstractText>Prolongation of electromechanical delay and increased Pd are associated with apnea-hypopnea index (AHI) and hence the severity of disease.</AbstractText>Copyright © 2011 Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,071 | Heart failure with recovered ejection fraction: a distinct clinical entity. | A subset of patients with heart failure (HF) and preserved left ventricular ejection fraction (EF) previously had EF <40%. We postulated that such "recovered" EF patients would be prevalent in a referral HF population and clinically distinct from those with persistently preserved or reduced EF.</AbstractText>We identified all subjects with a clinical diagnosis of HF seen in the advanced heart disease practice at our center from March to October 2008. Patients were classified into 1 of 3 groups based on retrospective review of the medical record: EF persistently ≥40% (HF-PEF), EF recovered to ≥40% (HF-REF) and low EF, <40% (HF-LEF). Clinical and echocardiographic characteristics were compared across groups using standard chi-square and analysis of variance tests. A total of 358 heart failure patients were identified, including 56 with HF-PEF, 121 with HF-REF, and 181 with HF-LEF. Compared with HF-PEF, HF-REF patients were younger with less atrial fibrillation, hypertension, and diabetes. Also, they tended to have lower systolic blood pressure, better renal function, and larger left ventricular diameter at end diastole. HF-REF patients were more similar to HF-LEF, but were younger and had lower rates of coronary artery disease. Of the 3 groups, HF-REF patients had the mildest reported HF symptoms and fewest previous HF hospitalizations.</AbstractText>Patients with HF-REF comprise a substantial proportion of those with HF and EF ≥40% followed in an ambulatory referral practice. These patients appear to be clinically distinct from the residual HF population and should be specifically targeted for further research.</AbstractText>Copyright © 2011 Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,072 | Reconstituted high-density lipoprotein shortens cardiac repolarization. | We hypothesize that increasing high-density lipoprotein cholesterol (HDL-C) shortens cardiac repolarization.</AbstractText>HDL-C is inversely associated with sudden death. The relation between HDL-C and repolarization of the heart is unexplored.</AbstractText>HDL-C was elevated with reconstituted high-density lipoprotein (rHDL). Cardiac repolarization was studied by recording cardiac transmembrane potentials with the patch clamp technique from isolated rabbit cardiomyocytes that were superfused with rHDL. Infusions with rHDL (40 mg/kg body weight) were performed in dyslipidemic patients and healthy volunteers. Electrocardiograms were recorded to assess cardiac repolarization before and 24 h after infusion with rHDL.</AbstractText>rHDL as well as purified human apolipoprotein AI shortened repolarization of isolated rabbit cardiomyocytes by ∼25% (p < 0.05). rHDL infusion shortened the heart rate-corrected QT interval on surface electrocardiograms in all participants (p < 0.001).</AbstractText>rHDL shortens cardiac repolarization. These data provide evidence for a novel mechanism of HDL infusion that may contribute to reduction of sudden cardiac death.</AbstractText>Copyright © 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,073 | Incidence and predictors of major complications from contemporary catheter ablation to treat cardiac arrhythmias. | Updated understanding of the risks of catheter ablation is important because techniques have evolved for procedures treating non-life-threatening as well as potentially lethal arrhythmias.</AbstractText>This prospective study sought to assess the incidence and predictors of major complications from contemporary catheter ablation procedures at a high-volume center.</AbstractText>Over a 2-year period, 1,676 consecutive ablation procedures were prospectively evaluated for major complications throughout 30 days postprocedure. Predictors of major complications were determined in a multivariate analysis adjusted for demographics, clinical variables, ablation type, and procedural factors.</AbstractText>Rates of major complications differed between procedure types, ranging from 0.8% for supraventricular tachycardia, 3.4% for idiopathic ventricular tachycardia (VT), 5.2% for atrial fibrillation (AF), and 6.0% for VT associated with structural heart disease (SHD). Ablation type (ablation for AF [odds ratio (OR) 5.53, 95% confidence interval (CI) 1.81 to 16.83], for VT with SHD [OR 8.61, 95% CI 2.37 to 31.31], or for idiopathic VT [OR 5.93, 95% CI 1.40 to 25.05] all referenced to supraventricular tachycardia ablation), and serum creatinine level >1.5 mg/dl (OR 2.48, 95% CI 1.07 to 5.76) were associated with increased adjusted risk of major complications, whereas age, gender, body mass index, international normalized ratio level, hypertension, coronary artery disease, diabetes, and prior cerebrovascular accident were not associated with increased risk.</AbstractText>In a large cohort of contemporary catheter ablation, major complication rates ranged between 0.8% and 6.0% depending on the ablation procedure performed. Aside from ablation type, renal insufficiency was the only independent predictor of a major complication.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,074 | Postpacing abnormal repolarization in catecholaminergic polymorphic ventricular tachycardia associated with a mutation in the cardiac ryanodine receptor gene. | Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an arrhythmogenic disease for which electrophysiological studies (EPS) have shown to be of limited value.</AbstractText>This study presents a CPVT family in which marked postpacing repolarization abnormalities during EPS were the only consistent phenotypic manifestation of ryanodine receptor (RyR2) mutation carriers.</AbstractText>The study was prompted by the observation of transient marked QT prolongation preceding initiation of ventricular fibrillation during atrial fibrillation in a boy with a family history of sudden cardiac death (SCD). Family members underwent exercise and pharmacologic electrocardiographic testing with epinephrine, adenosine, and flecainide. Noninvasive clinical test results were normal in 10 patients evaluated, except for both epinephrine- and exercise-induced ventricular arrhythmias in 1. EPS included bursts of ventricular pacing and programmed ventricular extrastimulation reproducing short-long sequences. Genetic screening involved direct sequencing of genes involved in long QT syndrome as well as RyR2.</AbstractText>Six patients demonstrated a marked increase in QT interval only in the first beat after cessation of ventricular pacing and/or extrastimulation. All 6 patients were found to have a heterozygous missense mutation (M4109R) in RyR2. Two of them, presenting with aborted SCD, also had a second missense mutation (I406T- RyR2). Four family members without RyR2 mutations did not display prominent postpacing QT changes.</AbstractText>M4109R- RyR2 is associated with a high incidence of SCD. The contribution of I406T to the clinical phenotype is unclear. In contrast to exercise testing, marked postpacing repolarization changes in a single beat accurately predicted carriers of M4109R- RyR2 in this family.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,075 | Reduced diameter spheres increases the risk of chest blow-induced ventricular fibrillation (commotio cordis). | Sudden death due to low-energy blunt trauma to the precordium (commotio cordis) has been described with a variety of sporting objects. However, the risk of ventricular fibrillation (VF) relative to the shape of the impact object is not known.</AbstractText>The objective of the current experiment is to test whether the impact object shape is a clinical variable that affects the risk for commotio cordis.</AbstractText>In a juvenile swine model, impacts were given in random order with two different spherical shapes (72 mm diameter, equivalent to a baseball; 42 mm diameter, equivalent to a golf ball) and a flat round object 72 mm in diameter. Objects were equal in weight (150 g), thrown at 30 mph, and gated to the vulnerable portion of the cardiac cycle.</AbstractText>Sixteen swine received 144 impacts. The flat object did not cause VF (P = .01 compared with the two spherical objects), nonsustained VF, ST elevation, or bundle branch block. The smaller diameter sphere caused VF in nine of 48 impacts (19%), and the larger diameter sphere caused VF in five of 48 impacts (10%; P = .25). The smaller diameter sphere was associated with a greater increase in left ventricular pressure (P <.0001 and P = .001 compared with larger sphere only) and a higher likelihood of ST segment elevations (P <.001 and P = .08 compared with larger sphere only) and bundle branch block (Fisher's exact P = .008, and Fisher's exact P = .18 compared with larger sphere only).</AbstractText>The shape of the projectile markedly influences the risk of VF from chest wall impact. This effect is likely mediated via a greater increase in left ventricular pressure with smaller diameter objects. Spreading the impact force over a larger area may decrease the risk of sudden death and has implications for the design of protective athletic equipment.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,076 | Protein kinase C downregulates I(Ks) by stimulating KCNQ1-KCNE1 potassium channel endocytosis. | The slow-activating cardiac repolarization K(+) current (I(Ks)), generated by the KCNQ1-KCNE1 potassium channel complex, is controlled via sympathetic and parasympathetic regulation in vivo. Inherited KCNQ1 and KCNE1 mutations predispose to ventricular fibrillation and sudden death, often triggered by exercise or emotional stress. Protein kinase C (PKC), which is activated by α1 adrenergic receptor stimulation, is known to downregulate I(Ks) via phosphorylation of KCNE1 serine 102, but the underlying mechanism has remained enigmatic. We previously showed that KCNE1 mediates dynamin-dependent endocytosis of KCNQ1-KCNE1 complexes.</AbstractText>This study sought to determine the potential role of endocytosis in I(Ks) downregulation by PKC.</AbstractText>We utilized patch clamping and fluorescence microscopy to study Chinese hamster ovary (CHO) cells coexpressing KCNQ1, KCNE1, and wild-type or dominant-negative mutant (K44A) dynamin 2, and neonatal mouse ventricular myocytes.</AbstractText>The PKC activator phorbol 12-myristate 13-acetate (PMA) decreased I(Ks) density by >60% (P < .05) when coexpressed with wild-type dynamin 2 in CHO cells, but had no effect when coexpressed with K44A-dynamin 2. Thus, functional dynamin was required for downregulation of I(Ks) by PKC activation. PMA increased KCNQ1-KCNE1 endocytosis in CHO cells expressing wild-type dynamin 2, but had no effect on KCNQ1-KCNE1 endocytosis in CHO cells expressing K44A-dynamin 2, determined using the Pearson correlation coefficient to quantify endosomal colocalization of KCNQ1 and KCNE1 with internalized fluorescent transferrin. KCNE1-S102A abolished the effect of PMA on I(Ks) currents and endocytosis. Importantly, PMA similarly stimulated endocytosis of endogenous KCNQ1 and KCNE1 in neonatal mouse myocytes.</AbstractText>PKC activation downregulates I(Ks) by stimulating KCNQ1-KCNE1 channel endocytosis.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,077 | Short-term variability of repolarization predicts ventricular tachycardia and sudden cardiac death in patients with structural heart disease: a comparison with QT variability index. | Monitoring arrhythmic risk may improve management of patients with implantable cardioverter-defibrillators (ICD) and prevent ICD shocks. Changes in repolarization duration between subsequent beats quantified as short-term variability (STV) is associated with ventricular arrhythmias in several animal models.</AbstractText>We evaluated STV of QT from right ventricular intracardiac ICD electrograms in patients with structural heart disease and compared its predictive value with the QT variability index (QTVI).</AbstractText>In 233 patients, STV over 60 beats for QT and RR intervals and their ratio was calculated (STV(QT), STV(RR), STV(Ratio), respectively). QTVI was derived from mean and SD of QT and heart rate. Follow-up duration was 26 ± 15 months. Predictive value was determined for sudden arrhythmic death (SAD) defined as sudden cardiac death or fast ventricular tachycardia/fibrillation [CL < 240 ms].</AbstractText>In univariate analysis, STV(Ratio), but not STV(QT) or STV(RR), was predictive of SAD. Hazard ratios for highest quartile STV(Ratio) and QTVI were comparable (STV(Ratio): 1.9, 95% confidence interval [CI] 1.1 to 3.3, P = .038, QTVI: 2.2, 95% CI 1.2 to 3.8, P = .010). In a multivariate model, highest quartile STV(Ratio) was predictive of SAD after adjustment for New York Heart Association class, history of ischemia, ICD indication, and use of class I antiarrhythmics (hazard ratio 1.8, 95% CI 1.0 to 3.4, P < .050). A combined criterion of highest quartile for both STV(Ratio) and QTVI identified patients at highest risk (hazard ratio 2.4, 95% CI 1.3 to 4.3, P = .005, positive predictive value 38%, negative predictive value 82%).</AbstractText>STV(Ratio) from ICD electrograms is predictive of SAD. Predictive value is similar for order-based STV(Ratio) and distribution-based QTVI, but the combination of both parameters can further improve results.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,078 | Cardiac resynchronization therapy and the relationship of percent biventricular pacing to symptoms and survival. | With the advent of cardiac resynchronization therapy, it was unclear what percentage of biventricular pacing would be required to obtain maximal symptomatic and mortality benefit from the therapy. The optimal percentage of biventricular pacing and the association between the amount of continuous pacing and survival is unknown.</AbstractText>The purpose of this study was to assess the optimal percentage of biventricular pacing and any association with survival in a large cohort of networked patients.</AbstractText>A large cohort of 36,935 patients followed up in a remote-monitoring network, the LATITUDE Patient Management system (Boston Scientific Corp., Natick, Massachusetts), was assessed to determine the association between the percentage of biventricular pacing and mortality.</AbstractText>The greatest magnitude of reduction in mortality was observed with a biventricular pacing achieved in excess of 98% of all ventricular beats. Atrial fibrillation and native atrial ventricular condition can limit a high degree of biventricular pacing. Incremental increases in mortality benefit are observed with an increasing percentage of biventricular pacing.</AbstractText>Every effort should be made to reduce native atrioventricular conduction with cardiac resynchronization therapy systems in an attempt to achieve biventricular pacing as close to 100% as possible.</AbstractText>Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.</CopyrightInformation> |
15,079 | Anesthetic management of patients with Brugada syndrome: a case series and literature review. | To review the anesthetic management and perioperative outcomes of patients diagnosed with Brugada syndrome (BrS) who were treated at a single centre and to compare those results with a comprehensive review of the existing literature.</AbstractText>A retrospective chart review of anesthesia records from patients diagnosed with BrS at the Mayo Clinic was undertaken with the emphasis on administered drugs, ST segment changes, and occurrence of complications, including death, hemodynamic instability, and dysrhythmias. Eight patients were identified who underwent a total of 17 operative procedures from 2000 through 2010. A total of 20 significant ST segment elevations were recorded in four patients, several of which occurred in close temporal relation to anesthetic drug administration. These elevations resolved uneventfully. There were no recorded dysrhythmias, and recovery from anesthesia proceeded uneventfully. A literature review of patients with BrS yielded 52 anesthetics in 43 patients. The only recorded complications included unmasking of a Brugada ECG pattern, one episode of polymorphic ventricular tachycardia, which converted spontaneously to sinus rhythm, and one episode of postoperative ventricular fibrillation in the setting of epidural anesthesia.</AbstractText>In this series and in the literature, BrS patients tolerated anesthesia without untoward disease-related complications. Propofol and local anesthetics carry a theoretical risk of arrhythmogenic potential in BrS patients, but clear evidence is lacking. However, awareness of their potential to induce arrhythmias warrants caution, especially with propofol infusions. Factors that might exacerbate ST segment elevations and subsequently lead to dysrhythmias (e.g., hyperthermia, bradycardia, and electrolyte imbalances, such as hyper- and hypokalemia and hypercalcemia) should be avoided or corrected.</AbstractText> |
15,080 | Ventricular fibrillation after exposure to air freshener-death just a breath away. | A case of ventricular fibrillation due to butane toxicity after unintentional inhalation of air freshener is reported for its rarity and to create awareness among practitioners and the public. A 25-year-old woman collapsed in the supermarket after unintended exposure to air freshener sprayed into her nostrils. Her husband started cardiopulmonary resuscitation immediately, and she was brought to the hospital. She had coarse ventricular fibrillation. Defibrillation with 360 J was given, and the rhythm reverted to normal sinus rhythm after the third shock. Epinephrine was not administered, and she was treated with esmolol infusion for ventricular ectopy. The patient recovered completely without any sequelae and was discharged on the fifth hospital day. On thin layer chromatography, the chemical content of the spray was identified to be isobutane. Avoiding epinephrine and administering β-adrenergic blockers may protect the catecholamine-sensitized heart early during resuscitation in butane exposure cases. |
15,081 | Left ventricular noncompaction syndrome masquerading or misdiagnosed as congenital long QT syndrome: remember QT prolongation does not equal long QT syndrome. | Distinguishing congenital long QT syndrome from QT prolongation caused by drugs or a different underlying disease process is essential for selecting the proper treatment. Herein, we present a case of a patient referred for left cardiac sympathetic denervation as a last resort treatment option for her 19-year standing diagnosis of long QT syndrome with malignant ventricular fibrillation. However, based on her atypical clinical course and additional imaging studies, a diagnosis of left ventricular noncompaction, rather than long QT syndrome, was made. She left the clinic with a drastically different treatment plan and an improved quality of life. Because many cardiac and noncardiac diseases can demonstrate QT prolongation on electrocardiogram, all possible diagnoses should be considered before diagnosing a patient with congenital long QT syndrome especially with regard to the profound treatment implications and genetic follow-up in family members. |
15,082 | Alterations in adhesion junction precede gap junction remodelling during the development of heart failure in cardiomyopathic hamsters. | The intercalated disc (ID) contains two complexes, the adhesion junction (AJ) and the gap junction (GJ). We studied ID remodelling and its potential role in arrhythmogenesis and investigated the effects of olmesartan on ID remodelling during development of heart failure (HF) in UM-X7.1 cardiomyopathic hamsters.</AbstractText>The UM-X7.1 hamsters showed left ventricular (LV) hypertrophy by the age of 10-15 weeks and a moderate impairment in LV contractility at 20 weeks. At age 10-15 weeks, 10-20% of the hamsters died suddenly without HF, and ventricular tachycardia (VT)/ventricular fibrillation (VF) was induced in ∼30% of hamsters. Electron microscopy showed that density linking cell-to-cell adhesion was irregular and unclearly defined, and filamentous structures attached to electron-dense components were arranged in disorder. Western blotting showed that the total cellular expression level of β-catenin was decreased, and expression of nuclear β-catenin, which functions as a T-cell factor/lymphocyte enhancer binding factor transcriptional activator, was also remarkably decreased. At age 20 weeks, LV connexin43 expression showed a remarkable decrease, and the VT/VF induction rate was ∼90%. In UM-X7.1 hamsters, olmesartan improved abnormal ID ultrastructural changes, attenuated the decrease of total cellular and nuclear β-catenin expression, decreased VT/VF induction, and improved survival rate.</AbstractText>These results suggest that changes in AJ protein precede connexin43 GJ alterations, and ID remodelling might contribute to arrhythmogenesis during the development of HF. Angiotensin receptor blockade might be a new therapy for lethal ventricular arrhythmia by modulating both AJ and GJ remodelling.</AbstractText> |
15,083 | Left stellate ganglion blockade for the management of drug-resistant electrical storm. |   Electrical storm (ES) is a syndrome characterized by rapidly recurrent ventricular fibrillation or tachycardia. The most common precipitants include ongoing or recent myocardial ischemia, exacerbating congestive heart failure, arrhythmogenic medications, and electrolyte disturbances.</AbstractText>  We describe the case of a patient who developed ES seventy-two hours status post triple vessel coronary artery bypass grafting that did not respond to conservative treatment and required approximately 70 electrical shocks.</AbstractText>  The patient was rapidly stabilized following left stellate ganglion blockade.</AbstractText>Wiley Periodicals, Inc.</CopyrightInformation> |
15,084 | Coronary angiography and intervention during hypothermia can be performed safely without cardiac arrhythmia or vasospasm. | Mild therapeutic hypothermia is a neuroprotective procedure after cardiac arrest. Therefore, it is increasingly used. Likewise, there is a growing demand for coronary angiography and percutaneous coronary interventions under hypothermia. Case studies suggested that hypothermia may be associated with coronary vasospasm, heart rhythm events and platelet dysfunction. In this study, it was evaluated whether vasospasm, arrhythmia or bleeding occur to a relevant degree during cardiac catheterization under concomitant hypothermia.</AbstractText>In this prospective, single-center, open-label, non-interventional study, 29 patients after resuscitation for cardiac arrest were treated with mild hypothermia and underwent cardiac catheterization (coronary angiography n = 11, coronary angiography plus percutaneous intervention n = 18). The incidence of vasospasm, cardiac arrhythmia and relevant bleeding at the puncture site were evaluated.</AbstractText>Mean temperature at cardiac catheterization was 33.9 ± 0.76°C. The mean heart rate was 82 ± 26 bpm at hospital admission and 67 ± 17 bpm under hypothermia (p < 0.05). There was no patient with relevant bradycardia beyond the expected hypothermia-induced rate reduction during the procedure. There were no unexpected ventricular tachycardias or episodes of ventricular fibrillation which might have been attributed to hypothermia. Twenty-nine of 29 patients (100%) were free from coronary vasospasm. There was no patient with a relevant bleeding at the puncture site. Potassium levels were low in 52% of the patients, even after resuscitation, which was partially attributed to hypothermia.</AbstractText>Coronary angiography and percutaneous coronary interventions under mild therapeutic hypothermia were safe in this small cohort and were performed without hypothermia-induced vasospasm, relevant rhythm events or bleeding complications. This result has to be confirmed in a large series of patients.</AbstractText> |
15,085 | Impact of renal failure on in-hospital outcomes after coronary artery bypass surgery. | Chronic kidney disease (CKD) is a predictor of increased mortality in patients undergoing coronary artery bypass surgery (CABG).</AbstractText>To evaluate the characteristics and predictors of increased mortality in the CKD population submitted to CABG. To compare in-hospital outcomes between patients with and without CKD, and with and without development of acute renal failure (ARF).</AbstractText>Retrospective analysis of a prospective database of all isolated CABG performed in a single public tertiary hospital from 1999 to 2007. CKD was considered when creatinine > 1.5 mg/dl. Clinical characteristics, mortality and post-operative complications were evaluated according to renal function.</AbstractText>Of 3,890 patients, 362 (9.3%) had CKD. This population was older, presented grater prevalence of hypertension, left ventricular dysfunction, previous stroke, peripheral vascular disease and three-vessel disease. In-hospital outcomes revealed greater incidence of stroke (5.5% vs 2.1%), atrial fibrillation (16 vs 8.3%), low cardiac ouput syndrome (14.4% vs 8.5%), longer stay in intensive care unit (4.04 vs 2.83 days), and greater mortality (10.5% vs 3.8%). Logistic regression: female gender, smoking, diabetes and peripheral vascular disease were associated with higher in-hospital mortality within the CKD group. Patients who did not develop post-operative ARF presented 3.5% mortality; non-dialytic ARF: 35.4%; dialytic ARF: 66.7% mortality. Mortality was directly related to the stage of CKD, according to glomerular filtration rate.</AbstractText>CKD patients submitted to CABG represent a high risk population, with increased incidence of complications and mortality. Post-operative ARF is a strong in-hospital mortality predictor. Glomerular filtration rate was inversely related to mortality.</AbstractText> |
15,086 | [Risk stratification in Brugada syndrome]. | Individuals with type 1 Brugada ECG pattern may suffer from malignant ventricular arrhythmias (Brugada syndrome). Patients with Brugada syndrome and documented cardiac arrest should receive an implantable cardioverter-defibrillator. In the remaining subjects, the best management is controversial. Many data suggest that patients with syncope, particularly if they have a spontaneous type 1 ECG pattern, have a significant risk. In the remaining population of asymptomatic subjects, the risk is lower but not negligible. How to manage these latter cases is an unsolved issue. The usefulness of the electrophysiological study (EPS) in risk stratification, i.e. inducibility of sustained ventricular tachycardia/fibrillation, is controversial. Indeed, some authors strongly support the prognostic value of EPS, while others completely deny its usefulness. We recently published our experience concerning the usefulness of a combined approach that considered both clinical data and EPS results; 320 patients (258 males, mean age 43 years) with type 1 ECG were enrolled. No patient had previous cardiac arrest; 54% of patients had a spontaneous and 46% a drug-induced type 1 ECG. One third had syncope, two thirds were asymptomatic; 245 patients underwent EPS; 110 patients received an implantable defibrillator. Patients were followed up for 40 months. During follow-up, 17 patients had major arrhythmic events (MAE) (14 resuscitated ventricular fibrillations and 3 sudden deaths). Both spontaneous type 1 ECG and syncope significantly increased the risk (8.6% and 10.4% event rates vs 2.8% and 1.3%). MAE occurred in 14% of subjects with positive EPS, in no subjects with negative EPS, and in 5.3% of subjects without EPS. All MAE occurred in subjects who had ≥ 2 risk factors (syncope, family history of sudden death and positive EPS). Among these patients, those with spontaneous type 1 ECG had a 30% event rate. In subjects with drug-induced type 1 MAE were rare. In conclusion, 1) in subjects with the Brugada type 1 ECG neither a single clinical risk factor nor EPS alone are able to identify subjects at the highest risk; 2) a multiparametric approach (including syncope, family history of sudden death and positive EPS) helps to identify populations at the highest risk; 3) subjects at the highest risk are those with a spontaneous type 1 ECG and ≥ 2 risk factors; 4) the remainder is at low risk. |
15,087 | Perishock pause: an independent predictor of survival from out-of-hospital shockable cardiac arrest. | Perishock pauses are pauses in chest compressions before and after defibrillatory shock. We examined the relationship between perishock pauses and survival to hospital discharge.</AbstractText>We included out-of-hospital cardiac arrest patients in the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest who suffered arrest between December 2005 and June 2007, presented with a shockable rhythm (ventricular fibrillation or pulseless ventricular tachycardia), and had cardiopulmonary resuscitation process data for at least 1 shock (n=815). We used multivariable logistic regression to determine the association between survival and perishock pauses. In an analysis adjusted for Utstein predictors of survival, the odds of survival were significantly lower for patients with preshock pause ≥20 seconds (odds ratio, 0.47; 95% confidence interval, 0.27 to 0.82) and perishock pause ≥40 seconds (odds ratio, 0.54; 95% confidence interval, 0.31 to 0.97) compared with patients with preshock pause <10 seconds and perishock pause <20 seconds. Postshock pause was not independently associated with a significant change in the odds of survival. Log-linear modeling depicted a decrease in survival to hospital discharge of 18% and 14% for every 5-second increase in both preshock and perishock pause interval (up to 40 and 50 seconds, respectively), with no significant association noted with changes in the postshock pause interval.</AbstractText>In patients with cardiac arrest presenting in a shockable rhythm, longer perishock and preshock pauses were independently associated with a decrease in survival to hospital discharge. The impact of preshock pause on survival suggests that refinement of automatic defibrillator software and paramedic education to minimize preshock pause delays may have a significant impact on survival.</AbstractText> |
15,088 | Single-center experience with implantable cardioverter-defibrillators in adults with complex congenital heart disease. | Adults with congenital heart disease are at risk of lethal ventricular arrhythmias and are candidates for implantable cardiac defibrillator (ICD) therapy, yet implant risks, long-term outcomes, and rates of appropriate and inappropriate ICD therapies are not well characterized. We reviewed clinical, implantation, and follow-up data on all transvenous ICDs in adults with congenital heart disease at the Mayo Clinic from 1991 through 2008. Seventy-three adults with congenital heart disease received 85 ICDs. Implantation diagnoses included tetralogy of Fallot (44%) and congenitally corrected transposition of the great arteries (17%). Implantation indication was occurrence of sustained ventricular arrhythmias (secondary prevention) in 36% and prophylactic (primary prevention) in the remainder. There were no major implant-related complications. During follow-up (2.2 ± 2.8 years, range 0 to 15) 11 patients died and 4 patients received heart or heart/lung transplants. An appropriate shock for a ventricular arrhythmia was observed in 19% of patients and an inappropriate shock was observed in 15% of patients. Likelihood of an appropriate shock was associated with increased subpulmonic ventricular pressure. In conclusion, implantation of transvenous ICDs in adults with congenital heart disease is associated with a low risk of implant complications. In this high-risk adult population the rate of inappropriate ICD shocks is low, whereas the likelihood of appropriate therapy for potentially lethal ventricular arrhythmias is high. These data suggest overall benefit of ICD therapy in adults with congenital heart disease. |
15,089 | Tissue doppler imaging and plasma BNP levels to assess the prognosis in patients with hypertrophic cardiomyopathy. | In addition to sudden death, heart failure and stroke due to atrial fibrillation are important in patients with hypertrophic cardiomyopathy (HCM). The aim of the present study was to determine whether Doppler tissue imaging findings and plasma B-type natriuretic peptide (BNP) levels, which are widely used for risk stratification in several cardiovascular diseases, are useful for risk stratification in patients with HCM in a regional cohort.</AbstractText>One hundred thirty patients (82 men; mean age, 60 ± 16 years) with HCM were enrolled in this study.</AbstractText>Twenty end points were observed during a mean follow-up period of 3.7 ± 1.7 years. Septal E/e' ratios and BNP levels in patients with events were higher than those in patients without events (17.4 ± 6.3 vs 10.6 ± 4.3, P < .0001, and 441 ± 304 vs 202 ± 174 pg/mL, P < .0001, respectively). By multivariate logistic regression analysis, a high septal E/e' ratio, in addition to a history of syncope and documentation of atrial fibrillation, was a significant predictor of combined end points. In contrast, plasma BNP levels were not a significant predictor of combined end points.</AbstractText>Assessment by Doppler tissue imaging is useful for further risk stratification of patients with HCM.</AbstractText>Copyright © 2011 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.</CopyrightInformation> |
15,090 | Electrocardiographic findings in patients with primary dysmenorrhea. | Primary dysmenorrhea (PD), which is characterized by painful menstrual cycles, is one of the common clinical problems in young adult women. The aim of this study was to investigate the risk of cardiac arrhythmias in PD patients by using the electrocardiographic (ECG) parameters.</AbstractText>Forty patients diagnosed with PD and 30 age-matched normal controls were included in this study. ECGs were performed by using 12-leads with 10 mV amplitude and 25 mm/sec velocity. P and QT waves were manually marked along the isoelectric line. P maximum, P minimum, QT maximum and QT minimum were measured on the surface 12-leads ECG, and the P wave and QT dispersions were calculated.</AbstractText>There was not any significant correlation of P wave dispersion and QT dispersion between the age, sex, body mass index, hemoglobin, fasting blood glucose or any other laboratory parameters. P wave dispersion was significantly longer in the PD group than the control group (61.4 ± 19 msec versus 57 ± 14 msec, P = 0.01). The P minimum duration was significantly shorter in the PD group compared with the control group (36 ± 16 msec versus 41 ± 9 msec, P = 0.03). QT dispersion was significantly higher in the PD group compared with normal controls (76 ± 23 msec versus 58 ± 16 msec, P = 0.02).</AbstractText>These results show that PD can be associated with cardiac arrhythmias, especially atrial fibrillation, by increasing P wave dispersion and ventricular arrhythmia risk because of an increased QT interval.</AbstractText> |
15,091 | RETRACTED: Ventricular Ectopic Beats: An Overview of Management Considerations. | Ventricular ectopic beats are commonly seen in daily clinical practice. Majority of them being asymptomatic, some can cause symptoms. In a normal heart, their occurrence is of no clinical significance. However, in the presence of an underlying heart disease, they signify a susceptibility toward more sinister arrhythmias. In some patients, they are triggered by the same mechanism as ventricular tachycardia and these can be cured by catheter ablation. Recent reports on the use of catheter ablation in cases where focal ventricular ectopics are found to trigger ventricular fibrillation. Clinical evaluation and investigations are important in assessing patients with ventricular ectopic beats so that appropriate treatment can be targeted when necessary. This article discusses the current knowledge and practice in this commonly encountered clinical problem. |
15,092 | Importance of evaluating conduction block in radiofrequency ablation for atrial fibrillation. | Atrial fibrillation (AF) is the most frequently diagnosed cardiac arrhythmia. Anti-arrhythmic drugs may be used to suppress ectopic foci and interrupt reentry circuits, but are often insufficient to treat recurrent AF and have a number of adverse effects. Alternative therapies, such as catheter and surgical ablation, have been explored. This investigation examines the importance of assessing exit block when performing surgical ablation during beating-heart treatment of AF.</AbstractText>This was an evaluation of pooled data from multicenter prospective results obtained in AF patients who received ablation with a new, irrigated, vacuum-integrated device that creates linear lesions during beating-heart/open-chest or minimally invasive, port-access procedures. Electrocardiogram or Holter data were collected intra-operatively and at 1, 3, 6, and 12 months. Outcomes were also evaluated for patients who were or 'were not' tested for exit block following the ablation procedure.</AbstractText>A total of 93 patients were treated (61 open-chest surgeries, 32 port-access procedures). There were no device-related complications and no operative mortality. At 341 days' average follow-up, 71/86 (83%) patients were free from AF, 66/86 (77%) were in sinus rhythm, and 60/86 (70%) were free from AF and off Class I and III anti-arrhythmic drugs (AADs). At 12 months, 23/23 (100%) patients with exit block confirmed were AF free compared with 13/21 (62%) patients with exit block not tested (p≤0.01, Fisher's exact test); 20/23 (87%) were in sinus rhythm compared with 12/21 (57%) patients with exit block not tested (p≤0.05, Fisher's exact test); and 20/23 (87%) were AF free without Class I and III AADs compared with 10/21 (48%) patients with exit block not tested (p≤0.01, Fisher's exact test). Both open-chest and port-access procedures yielded decreases in left-atrial size from baseline to 6 months' follow-up. Patients undergoing port-access procedures also observed an increase in left-ventricular ejection fraction, which was also significant at 6 months.</AbstractText>Patients in whom exit block was confirmed following an ablation procedure were more likely to have successful clinical outcomes. Since testing for exit block must be performed on a beating heart, total epicardial beating-heart ablation may provide an important treatment for AF, providing intra-operative feedback indicative of long-term outcomes.</AbstractText> |
15,093 | Twelve hours of sustained ventricular fibrillation supported by a continuous-flow left ventricular assist device. | Left ventricular assist device (LVAD) therapy improves survival and quality of life by mechanically unloading the left ventricle and maintaining hemodynamics in patients with end-stage heart failure. LVADs can also be lifesaving by maintaining hemodynamics during ventricular arrhythmia. Continuous-flow LVADs have become the preferred LVAD technology. As presented here, a continuous-flow LVAD successfully provided hemodynamic support to a patient in sustained ventricular fibrillation for over 12 hours when the internal defibrillator was unable to terminate the arrhythmia. This case demonstrates that continuous-flow LVADs can be lifesaving in the setting of otherwise certain hemodynamic collapse from sustained ventricular fibrillation. |
15,094 | Acute heart failure with dyspnoea: initial treatment. Furosemide and trinitrine, despite the lack of a proven survival benefit. | For patients with acute heart failure and dyspnoea due to pulmonary congestion, the risk of death in the short term is high. To determine how best to manage these patients, we reviewed the relevant literature using the standard Prescrire methodology. There are few reliable clinical trial data. None of the available drugs has been shown to improve survival. Loop diuretics such as furosemide improve some haemodynamic parameters and dyspnoea due to congestion, i.e., water and salt retention. The dose is adjusted on the basis of clinical response, renal status and previous use of a loop diuretic, especially in chronic heart failure. The main adverse effects of loop diuretics are hypotension, hyponatraemia, hypokalaemia, renal failure and ototoxicity. Compared with repeated injections, continuous infusion seems to carry a lower risk of death and ototoxicity. High doses are associated with excess mortality. Nitrate derivatives such as trinitrine and isosorbide dinitrate are vasodilators. Only intravenous administration has been assessed in acute heart failure. These drugs improve certain haemodynamic parameters, reduce blood pressure and increase coronary flow.Their effect declines rapidly above a certain dose in about 20% of patients. They seem to improve dyspnoea and, according to a difficult-to-interpret trial of isosorbide dinitrate, may reduce the risk of myocardial infarction. There is no firm evidence that nitrate derivatives improve survival in patients with acute heart failure, but they reduce mortality in patients with myocardial infarction, a frequent cause of acute heart failure. The main adverse effect of nitrate derivatives is hypotension, meaning that these drugs should not be used when blood pressure is low and that blood pressure should be closely monitored during treatment. Randomised trials of another vasodilator, nesiritide, showed excess mortality at 30 days. There are no such trials of nitrate derivatives. In patients with cardiogenic shock, inotropes (mainly dopamine, dobutamine and milrinone) improve symptoms and haemodynamic parameters but may increase mortality.These drugs carry a risk of ventricular and supraventricular arrhythmias and tachycardia. Their use requires continuous monitoring in an intensive care unit. Cardiac glycosides, including digoxin, have been used empirically in acute heart failure. The use of digoxin is mentioned in only one clinical practice guideline, in patients with atrial fibrillation and a rapid heart rate. Its narrow therapeutic margin and its frequent interactions with other drugs make digoxin difficult to use. Oxygen is usually recommended in case of hypoxaemia but its clinical value has not been assessed comparatively in acute heart failure. In some trials, routine oxygen delivery, without taking into account the degree of hypoxia, appeared to be harmful in patients with myocardial infarction. Non-invasive ventilation has been assessed in several comparative randomised trials, in which it was found to improve some physiological parameters. In a trial in 1069 patients, it had no impact on mortality at 30 days, or on the need for endotracheal intubation. It is not appropriate for patients with respiratory distress necessitating intubation, or with altered consciousness, severe dementia, major anxiety. It is often poorly tolerated. Its main adverse effects are aggravation of right heart failure, pneumothorax, and aspiration of gastric contents. Early treatment probably improves outcome. Clinical practice guidelines recommend urgent hospitalisation of patients with acute heart failure. In summary, the choice of initial treatment for patients with acute heart failure and dyspnoea depends largely on blood pressure.Treatment is mainly based on loop diuretics, nitrate derivatives (when blood pressure is not too low) and non-invasive ventilation. It should be emphasised that these patients are highly unstable and that there is a narrow margin between beneficial and harmful effects of available treatments. Patients receiving treatment should always be closely monitored. |
15,095 | Appropriate therapy but not inappropriate shocks predict survival in implantable cardioverter defibrillator patients. | Inappropriate implantable cardioverter defibrillator (ICD) shocks have been linked to a worse clinical outcome due to direct myocardial injury.</AbstractText>The occurrence of ventricular tachyarrhythmia indicating progression of the underlying heart disease, but not the ICD shock itself, has prognostic impact in clinical routine.</AbstractText>In a retrospective study, 1117 recipients of an ICD were analyzed with respect to appropriate and inappropriate therapies and survival.</AbstractText>During a mean follow-up of 2.92 years, appropriate therapy occurred in 27.7% and 54.0% of patients who had received an ICD for primary and secondary prevention of sudden cardiac death (SCD), respectively (P<0.0001). Inappropriate shock therapy occurred in 15.0% and 25.4% of patients who had received an ICD for primary and secondary prevention of SCD, respectively (P = 0.122). Appropriate ICD therapy had a strong impact on overall survival (P<0.0001), and this association was found both in primary (P<0.0001) and secondary (P = 0.002) prevention of SCD. Inappropriate ICD shocks had no impact on total mortality, neither in primary nor secondary prevention of SCD.</AbstractText>Inappropriate shocks do not affect survival, in strong contrast to appropriate ICD therapy. Our study does not support the hypothesis that shock therapy in itself worsens clinical outcome. However, it confirms that appropriate ICD therapy is a warning sign and should prompt physicians to consider additional treatment strategies.</AbstractText>© 2011 Wiley Periodicals, Inc.</CopyrightInformation> |
15,096 | [Acute pulmonary embolism following cardiac arrest in a 31 year-old female with long QT syndrome]. | A case of a young female with acute pulmonary embolism following cardiac arrest due to ventricular fibrillation as a result of long QT syndrome is presented. A differential diagnosis has been discussed. |
15,097 | Microvolt T-wave alternans for the risk stratification of dangerous ventricular arrhythmias in patients with previously implanted automatic cardioverter-defibrillator. | Sudden cardiac death (SCD) is the main cause of death in patients with reduced left ventricular ejection fraction (LVEF). Implantation of an automatic cardioverter-defibrillator (ICD) significantly reduces mortality of these patients. T-wave alternans (TWA) analysis is a relatively new method of SCD risk stratification. However, it's prognostic role in patients with ICD has not yet been fully established.</AbstractText>To assess the predictive value of TWA in patients with previously implanted ICD.</AbstractText>The study included 67 patients with properly functioning ICD (54 men and 13 women, aged 62.2 ± 8.4 years). All patients underwent TWA analysis on the treadmill using the Cambridge Heart 2000 system. Results were considered as positive, negative or indeterminate. Each patient had at least 1 clinical control visit with ICD interrogation during the 12 ± ± 6 months of follow-up. The recurrence of sustained ventricular arrhythmias: ventricular tachycardia (VT) or ventricular fibrillation (VF) was analysed.</AbstractText>No significant relationship was found between previous infarction (p = 0.810), aetiology (p = 0.768), LVEF (p = 0.413) or age (p = 0.562) and the incidence of arrhythmia during follow-up. The results of TWA were not significantly different between patients with or without VT or VF. The TWA analysis identified patients with arrhythmia recurrences with a sensitivity of 62%, specificity of 49%, negative predictive value of 81%, and positive predictive value of 28%. The TWA performance was better in patients with non-ischaemic than ischaemic cardiomyopathy (negative predictive value: 100%, positive predictive value: 75%).</AbstractText>The TWA alternans was moderately effective for identification of patients with ICD and ventricular arrhythmia recurrences. The test was most useful for identification of patients with non-ischaemic cardiomyopathy who are of low arrhythmic risk.</AbstractText> |
15,098 | Prolonged P wave dispersion in pre-diabetic patients. | It is known that overt diabetes as well as chronic hyperglycaemia can lead to atrial fibrillation. A P wave dispersion (PWD) represents heterogeneity in atrial refractoriness.</AbstractText>To investigate PWDs in patients with pre-diabetes.</AbstractText>Based on the results of examinations, 84 pre-diabetic patients (the pre-DM group; 50 female, 34 male; mean age 54 ± 8.6 years) who had no overt diabetes, coronary artery disease or hypertension, whose fasting blood glucose was higher than 100 mg/dL and/or whose 2 h glucose concentrations on an oral glucose tolerance test was in the range of 140 to 199 mg/dL, and 48 healthy volunteers (the non-DM group, 30 female, 18 male; mean age 51.7 ± 7.3 years) with no illnesses, were enrolled in this study. Standard 12-lead electrocardiograms of all patients were taken at 50 mm/s and 20 mm/mV standardisation. Maximum (P(max)) and minimum (P(min)) P-wave durations were measured. The PWD was defined as the difference between P(max) and P(min).</AbstractText>The P(max) and PWD values were significantly higher in pre-DM compared to non-DM (104 ± 13 ms vs 98 ± 12 ms; p < 0.05, 42 ± 13 ms vs 34 ± 11 ms; p <0.01 respectively). A positive correlation was found between PWD and fasting blood glucose (r = 0.32; p < 0.01). There was no correlation between PWD and HbA(1c) levels (r = 19; p > 0.05). Multivariate regression analysis showed no relationship between PWD and age, left atrial diameter, E, A, E/A or HbA(1c). However, there was a relationship between PWD and fasting blood glucose.</AbstractText>The P(max) and PWD are increased in pre-diabetic patients who have no coronary artery disease, hypertension or left ventricular hypertrophy</AbstractText> |
15,099 | Intermediate and long-term followup of percutaneous device closure of fossa ovalis atrial septal defect by the Amplatzer septal occluder in a cohort of 529 patients. | The aim of present study is to analyze the intermediate and long-term follow up results of percutaneous closure of fossa ovalis atrial septal defect (ASD) with Amplatzer septal occluder (ASO) in a large cohort of patients including children and adults.</AbstractText>Between May 1998 and July 2008, 529 patients (age group 2-77 years, median 28 years) underwent successful device closure with an ASO at single tertiary referral cardiac center in India.. This was out of an attempted 543 cases. The procedure was carried out in catheterization laboratory under transesophageal echocardiographic and fluoroscopy guidance. The mean size of ASD was 20 mm (7-40 mm) while size of septal occluder was 10-40 mm (mean 24 mm). Two devices were deployed in four patients. Three patients developed transitory pulmonary edema in immediate postprocedure period requiring ICU care for 48 hrs. All patients were advised for Aspirin (3-5 mg/kg, maximum 150 mg) once daily for 6 months. In patients with device 30 mm or larger, Clopidogril ( 75 mg once daily) was given for 3 months in addition to Aspirin. Clinical evaluation, echocardiogram were done on 3 months, 6 months and then at 1, 3, 5, 7 and 10 years of follow up. Transesophageal echocardiography (TEE) was performed in case of any doubt on clinical evaluation or on transthoracic echocardiography (n=10).</AbstractText>Followup data is available for 496 patients (93.7%). Followup period is from 12 months to 120 months (median 56 months). On followup, device was in position in all patients, no residual shunt and no evidence of thrombosis. Interventricular septal motion normalized on day of procedure in 89% patients, in 6% over 3 months while flat septal motion persisted in 5% (n=25, all in age group > 40 years) of cases, though right ventricular dilatation persisted in 10% (n=50, age more than 40 years) of patients. Symptom-free survival was 96.7 % (480/496) in patients who came for followup. Only one 68 year old patient with preexistent tricuspid regurgitation developed congestive heart failure, and one patient (58 years old) had a history of hemiparesis after 1 year of device on telephonic interview. Ten patients were in atrial fibrillation (AF) before the procedure and remained in AF on followup.</AbstractText>Our study showed that percutaneous closure of fossa ovalis ASD is a safe and effective procedure on intermediate and long-term followup in both the children as well as adults.both. Technical factors during the procedure and proper follow up are important. Our single centre intermediate and long term experience in a large number of patients support the use of device closure as an alternative to surgery.</AbstractText> |
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