Showing papers on "QRS complex published in 2009"

Cardiac-resynchronization therapy for the prevention of heart-failure events.

Abstract: During a 4.5-year period, we enrolled and followed 1820 patients with ischemic or nonischemic cardiomyopathy, an ejection fraction of 30% or less, a QRS duration of 130 msec or more, and New York Heart Association class I or II symptoms. Patients were randomly assigned in a 3:2 ratio to receive CRT plus an implantable cardioverter– defibrillator (ICD) (1089 patients) or an ICD alone (731 patients). The primary end point was death from any cause or a nonfatal heart-failure event (whichever came first). Heartfailure events were diagnosed by physicians who were aware of the treatment assignments, but they were adjudicated by a committee that was unaware of assignments. Results During an average follow-up of 2.4 years, the primary end point occurred in 187 of 1089 patients in the CRT–ICD group (17.2%) and 185 of 731 patients in the ICD-only group (25.3%) (hazard ratio in the CRT–ICD group, 0.66; 95% confidence interval [CI], 0.52 to 0.84; P = 0.001). The benefit did not differ significantly between patients with ischemic cardiomyopathy and those with nonischemic cardiomyopathy. The superiority of CRT was driven by a 41% reduction in the risk of heart-failure events, a finding that was evident primarily in a prespecified subgroup of patients with a QRS duration of 150 msec or more. CRT was associated with a significant reduction in left ventricular volumes and improvement in the ejection fraction. There was no significant difference between the two groups in the overall risk of death, with a 3% annual mortality rate in each treatment group. Serious adverse events were infrequent in the two groups. Conclusions CRT combined with ICD decreased the risk of heart-failure events in relatively asymptomatic patients with a low ejection fraction and wide QRS complex. (ClinicalTrials.gov number, NCT00180271.)

Pulmonary Valve Replacement in Tetralogy of Fallot Impact on Survival and Ventricular Tachycardia

Abstract: Background— Pulmonary valve replacement (PVR) in repaired tetralogy of Fallot (TOF) reduces pulmonary regurgitation and decreases right ventricular (RV) dilation, but its long-term impact on ventricular tachycardia (VT) and mortality is unknown. This study aimed to determine the incidence of death and VT in TOF after PVR and to test the hypothesis that PVR leads to improvement in these outcomes. Methods and Results— A total of 98 patients with TOF and late PVR for RV dilation were identified. Matched control subjects were identified for 77 of these patients; control subjects had TOF with RV dilation but no PVR. Matching was done by age (±2 years) and baseline QRS duration (±30 ms). No significant differences were found in age, QRS duration, type or decade of initial repair, age at TOF repair, or presence of pre-PVR VT between the 2 groups; limited echocardiographic and magnetic resonance imaging data showed no difference in left ventricular function but more RV dilation among PVR patients than control sub...

Surface electrocardiogram to predict outcome in candidates for cardiac resynchronization therapy: a sub-analysis of the CARE-HF trial.

Abstract: Aims In CARE-HF, cardiac resynchronization therapy (CRT) lowered morbidity and mortality in patients with moderate to severe heart failure. We examined whether baseline and follow-up electrocardiographic characteristics might predict long-term outcome. Methods and results CARE-HF randomly assigned 409 patients to medical therapy (MT) plus CRT, and 404 patients to MT alone. Electrocardiographic measurements were made at baseline during sinus rhythm, and at 3 months during paced or spontaneous rhythm depending on treatment assignment. Favourable outcome was defined as freedom from death, urgent transplantation, or cardiovascular hospitalization. Among patients assigned to CRT, 39% had unfavourable outcomes including 55 deaths. By single variable analysis, (i) prolonged PR interval, left QRS axis (but not QRS duration), and left bundle branch block (BBB) at baseline, and (ii) heart rate, PR, and QRS duration at 3 months predicted unfavourable outcome. By multiple variable analysis, treatment assignment (P = 0.0001), PR (P = 0.0004), and right BBB (P < 0.00013) at baseline predicted outcome, whereas baseline JTc and QRS duration at 3 months predicted all-cause mortality and heart failure hospitalization (P = 0.0071). Conclusion In CARE-HF, QRS duration at baseline did not predict outcome, but QRS at 3 months was a predictor by single variable analysis. Patients with prolonged PR interval and the 5% of patients with right BBB had a particularly high event rate.

Ventricular arrhythmias and sudden death in adults after a Mustard operation for transposition of the great arteries

Abstract: Aims To examine the prevalence of sustained ventricular tachycardia (VT) and sudden death (SD) in adults with atrial repair of transposition of the great arteries (TGA) and to determine associated risk factors. Methods and results In a single-centre review, we studied the outcome of 149 adults (mean age 28 ± 7 years) who had undergone a Mustard operation for TGA. During a mean follow-up of 9 ± 6 years, sustained VT and/or SD occurred in 9% (13/149) of the cohort. Sustained VT/SD was more likely to occur in patients with associated anatomic lesions [hazard ratio (HR) 4.9, 95% CI 1.5–16.0], with NYHA class ≥III (HR 9.8, 95% CI 3.0–31.6) and with an impaired subaortic right ventricular (RV) ejection fraction (EF) (HR 2.2, 95% CI 1.2–4.0 per 10% decrease in EF). There was an inverse correlation between the RV-EF and both age and QRS duration. Patients with a QRS duration ≥140 ms were at highest risk of sustained VT/SD (HR 13.6, 95% CI 2.9–63.4). Atrial tachyarrhythmia was detected in 66 (44%) patients, but was not a statistically significant predictor of sustained VT/SD in our adult population (HR 2.7, 95% CI 0.6–13.0). Conclusion Sustained VT/SD in adults after a Mustard operation for TGA are more common than previously described. Age, systemic ventricular function, and QRS duration are interrelated and are associated with VT/SD. A QRS duration ≥140 ms helps to identify the high risk patient.

Usefulness of Fragmented QRS on a 12-Lead Electrocardiogram in Acute Coronary Syndrome for Predicting Mortality

Abstract: Electrocardiographic signs of a non–ST elevation myocardial infarction (NSTEMI) are nonspecific, and therefore the diagnosis of NSTEMI during acute coronary syndromes (ACS) depends mainly on cardiac biomarker levels. Fragmented QRS (fQRS) represents myocardial conduction abnormalities due to myocardial infarction (MI) scars in patients with coronary artery disease. However, the time of appearance of fQRS during ACS has not been investigated. It was postulated that in patients with ACS, fQRS on 12-lead electrocardiography occurs within 48 hours of presentation with NSTEMI as well as ST elevation MI and that fQRS predicts mortality. Serial electrocardiograms from 896 patients with ACS (mean age 62 ± 11 years, 98% men) who underwent cardiac catheterization were studied. Four hundred forty-one patients had MIs, including 337 patients with NSTEMIs, and 455 patients had unstable angina (the control group). Serial electrocardiograms were obtained every 6 to 8 hours during the first 24 hours after the diagnosis of MI and the next day (

Predicting ventricular arrhythmias in patients with ischemic heart disease: clinical application of the ECG-derived QRS-T angle.

Abstract: Background— In patients with primary prevention implantable cardioverter-defibrillators (ICDs), the incidence of life-threatening ventricular arrhythmias resulting in ICD therapy is relatively low,...

Clinical features in poisonings by tricyclic antidepressants with special reference to the ECG.

Abstract: Clinical variables, and especially their relation to the ECG, have been studied in 153 cases of poisonings by tricyclic antidepressants (TCA). The mean age of the patients was 34 years. Amitriptyline poisoning accounted for 112 (73%) of the cases and the mean dose ingested was about 1 000 mg. Coma was present in 87 patients (57%) and on admission 40 (26%) had a systolic blood pressure (BP) below 100 mmHg. The systolic BP on admission was significantly lower (p less than 0.001) and the heart rate (HR) higher (p less than 0.001) than when the patients left the ward. Apart from an increased HR (greater than or equal to 90 beats/min), which was present in 73% of the cases, the most characteristic ECG change was a QRS prolongation (greater than or equal to 0.11 sec), this being found in 42% of the cases. About the same proportion displayed a QT prolongation and 28% had a prolonged PQ time. The mean of the QRS times was 0.11 sec. Unlike the QT time, the QRS time was not correlated to HR. Statistical analysis of the material with regard to clinical variables (dose of TCA, BP, coma duration, etc.) showed that the QRS time was closely related to the severity of poisoning. Five patients (3) died, all of whom already on admission demonstrated advanced ECG changes with arrhythmias and a mean QRS time of 0.19 sec. Excluding dibenzepine poisonings (4 cases, all fatal), the mortality rate was 0.7%. The importance of high initial preparedness for cardiac complications is pointed out, as is the value of the QRS time as a guide to the severity of poisoning.

Rapid initial reduction of hyperenhanced myocardium after reperfused first myocardial infarction suggests recovery of the peri-infarction zone: one-year follow-up by MRI.

Abstract: Background— The time course and magnitude of infarct involution, functional recovery, and normalization of infarct-related electrocardiographic (ECG) changes after acute myocardial infarction (MI) are not completely known in humans. We sought to explore these processes early after MI and during infarct-healing using cardiac MRI. Methods and Results— Twenty-two patients with reperfused first-time MI were examined by MRI and ECG at 1, 7, 42, 182, and 365 days after infarction. Global left ventricular function and regional wall thickening were assessed by cine MRI, and injured myocardium was depicted by delayed contrast-enhanced MRI. Infarct size by ECG was estimated by QRS scoring. The reduction of hyperenhanced myocardium occurred predominantly during the first week after infarction (64% of the 1-year reduction). Furthermore, during the first week the amount of nonhyperenhanced myocardium increased significantly ( P <0.001), although the left ventricular mass remained unchanged. Left ventricular ejection fraction increased gradually, whereas the greater the regional transmural extent of hyperenhancement at day 1, the later the recovery of regional wall thickening. Regional wall thickening decreased progressively with increasing initial transmural extent of hyperenhancement ( P trend<0.0001). The time course and magnitude of decrease in QRS score corresponded with the reduction of hyperenhanced myocardium. Conclusions— The early reduction of hyperenhanced myocardium may reflect recovery of hyperenhanced, reversibly injured myocardium, which must be considered when predicting functional recovery from delayed contrast-enhanced MRI findings early after infarction. Also, the time course and magnitude for reduction of hyperenhanced myocardium were associated with normalization of infarct-related ECG changes. Received June 26, 2008; accepted November 19, 2008. # CLINICAL PERSPECTIVE {#article-title-2}

Usefulness of baseline electrocardiographic QRS complex pattern to predict response to cardiac resynchronization.

Abstract: Cardiac resynchronization therapy (CRT) improves morbidity and mortality in patients with heart failure with QRS >120 ms, yet most patients studied in clinical trials manifested baseline left branch bundle block (LBBB). It is unclear whether benefits of CRT extend to patients with right branch bundle block (RBBB) or a paced QRS at baseline despite QRS >120 ms. Orthotopic heart transplantation– and ventricular assist device–free survival, symptomatic response, and echocardiographic response were evaluated in the 636 patients who underwent CRT at our institution from 2000 to 2007 in whom the baseline electrocardiogram showed LBBB (n = 412; 65%), paced QRS (n = 162; 26%), or RBBB (n = 62; 10%). Mortality was assessed using the Social Security Death Index, and the medical record was analyzed for clinical data. A decrease in New York Heart Association class ≥0.5 after ≥6 months of CRT defined symptomatic response. Echocardiographic evidence of improved left ventricular function and reverse remodeling was evaluated after ≥6 months of CRT. Survival free from orthotopic heart transplantation and ventricular assist device placement was best in patients with LBBB and worst in those with RBBB, whereas patients with paced QRS had an intermediate prognosis (p = 0.003). This finding remained significant after controlling for baseline differences among the 3 groups. Symptomatic response was observed most often in patients with LBBB (60%), occurred least often in patients with RBBB (14%), and was intermediate in patients with paced QRS (46%; p

Electrocardiographic and cardiac magnetic resonance imaging parameters as predictors of a worse outcome in patients with idiopathic dilated cardiomyopathy.

Abstract: Aims Clinical parameters are weak predictors of outcome in patients with idiopathic dilated cardiomyopathy (IDC). We assessed the prognostic value of cardiac magnetic resonance (CMR) parameters in addition to conventional clinical and electrocardiographic characteristics. Methods and results One hundred and forty-one IDC patients were studied. QRS and QTc intervals were measured in 12-lead surface electrocardiogram. Patients were followed for median 1339 days, including 483 patient-years. The primary endpoint—cardiac death or sudden death—occurred in 25 (18%) patients, including 16 patients with cardiac death, 3 patients with sudden cardiac death (SCD), and 6 patients with ICD shock. Late gadolinium enhancement (LGE) was detected in 36 patients (26%). Kaplan–Meier survival analysis displayed QRS >110 ms ( P = 0.010), the presence of LGE ( P = 0.037), and diabetes mellitus ( P 110 ms ( P = 0.045) as significant predictors for the primary endpoint. Conclusion Cardiac index and RVEDVI derived from CMR imaging in addition to QRS duration >110 ms from conventional surface ECG and diabetes mellitus provide prognostic impact for cardiac death and SCD in patients with IDC.

Adverse left ventricular mechanics in adults with repaired tetralogy of Fallot.

Abstract: Left ventricular (LV) dysfunction is a predictor of adverse outcomes in patients with repaired tetralogy of Fallot (TOF). However, the mechanisms for LV dysfunction are not well understood. The aim of the study was to determine whether the prolonged QRS duration of right branch bundle block was associated with adverse LV mechanics. Seventy-five patients (mean age 31 +/- 2 years) with repaired TOF were studied. LV and right ventricular (RV) volumes and ejection fractions (EFs) were assessed using cardiac magnetic resonance imaging. Vector velocity imaging was used to assess longitudinal strain and intraventricular dyssynchrony. Prolonged QRS duration was associated with increased RV and LV dimensions (p = 0.01) and decreased function (RVEF r = -0.60, p <0.001 and LVEF r = -0.77, p <0.001). In addition, prolonged QRS duration was associated with heterogeneous ventricular mechanical activation and reduced strain in the lateral and septal left ventricle walls. Degree of intraventricular dyssynchrony correlated with LVEF (r = -0.59, p <0.001), QRS duration (r = 0.74, p <0.001), and septal strain (r = 0.70, p <0.001). In conclusion, LV dysfunction and dyssynchrony were observed in patients with TOF and were associated with QRS duration. It was possible that abnormal LV mechanics in combination with RV dysfunction may explain the relation between QRS duration and adverse cardiac outcomes.

Ability of Terminal QRS Notching to Distinguish Benign from Malignant Electrocardiographic Forms of Early Repolarization

Abstract: Recent studies have suggested that early repolarization (ER) might be associated with up to 1/3 of idiopathic ventricular tachycardia/ventricular fibrillation (VT/VF) cases ("malignant" ER). We sought to identify electrocardiographic features to distinguish benign from malignant variants of ER. We reviewed the medical records for implantable-cardioverter defibrillators implanted at a single institution (1988 to 2008) to identify cases of idiopathic VT/VF. The electrocardiograms were scored for ER, defined as a >or=0.1-mV elevation of the QRS-ST junction manifesting as J-point slurring or notching in 2 contiguous leads. We also identified a cohort of 200 healthy age- and gender-matched controls with electrocardiographic findings previously identified as normal ER ("benign" ER cohort). Of 1,224 consecutive implantable-cardioverter defibrillator implants, we identified 39 cases of idiopathic VT/VF. Of the 39 cases, 9 (23%) demonstrated ER. During a mean follow-up of 7.2 +/- 4.6 years, the combined end point of appropriate implantable-cardioverter defibrillator shocks or all-cause mortality occurred less frequently in cases of idiopathic VT/VF with ER than in those without ER (11% vs 30%, odds ratio 0.29, 95% confidence interval 0.03 to 2.69, p = 0.40). A comparison of the electrocardiograms between those with malignant ER and controls demonstrated that QRS notching was significantly more prevalent among cases when present in leads V4 (44% vs 5%, p = 0.001) and V5 (44% vs 8%, p = 0.006), with a similar trend in lead V6 (33% vs 5%, p = 0.013). In conclusion, left precordial terminal QRS notching is more prevalent in malignant variants of ER than in benign cases. These findings could have important implications for risk stratification of patients with ER.

Effect of Long-Term Resynchronization Therapy on Left Ventricular Remodeling in Pacemaker Patients Upgraded to Biventricular Devices

Abstract: Right ventricular pacing resulted in abnormal ventricular depolarization and an activation pattern similar to left branch bundle block. In some circumstances, it may exacerbate symptoms of heart failure and increase hospital admission rates. The objective of this study was to assess the effects of long-term ventricular resynchronization therapy on echocardiographic parameters of left ventricular (LV) remodeling in patients with moderate to severe heart failure who were upgraded from single- to biventricular pacing. Twenty-six consecutive pacemaker-dependent patients (20 men; mean age 61 +/- 20 years) who underwent placement of an LV lead to upgrade their conventional pacing system to biventricular pacing were included in the study. All patients had heart failure symptoms, received the maximum tolerated medical therapy, and were stable for >or=1 month before the upgrade. Echocardiography and electrocardiography were performed before the pacemaker upgrade and at follow-up (mean duration 15 +/- 9 months). QRS duration decreased significantly from 176 +/- 23 to 154 +/- 19 ms (p <0.001). LV end-diastolic volume (p = 0.006) and LV end-systolic volume (p = 0.004) decreased at follow-up compared with baseline. The decrease in LV volumes observed during follow-up was accompanied by a significant increase in ejection fraction (39 +/- 11% to 46 +/- 10%; p = 0.001) and decrease in LV myocardial performance index (0.84 +/- 0.18 to 0.68 +/- 0.14; p = 0.001). The upgrade of conventional pacing to biventricular pacing resulted in significant prolongation of normalized LV filling time (p = 0.01) and shortening of isovolumic contraction time (p 0.002). In addition, biventricular pacing significantly (V-V interval = 0) reduced intra- (44 +/- 11 vs 18 +/- 12 ms; p <0.001) and interventricular dyssynchrony (78 +/- 33 vs 49 +/- 22 ms; p <0.001). In conclusion, these findings suggested that in patients with advanced heart failure and continuous right ventricular pacing, upgrading to biventricular system resulted in significant reverse LV remodeling in the long-term follow-up and improvement in overall synchronicity of ventricular function.

Impact of Cardiac Contractility Modulation on Left Ventricular Global and Regional Function and Remodeling

Abstract: OBJECTIVES This study aimed to evaluate the impact of cardiac contractility modulation (CCM) on left ventricular (LV) size and myocardial function. BACKGROUND CCM is a device-based therapy for patients with advanced heart failure. Previous studies showed that CCM improved symptoms and exercise capacity; however, comprehensive assessment of LV structure, function, and reverse remodeling is not available. METHODS Thirty patients (60 11 years, 80% male) with New York Heart Association (NYHA) functional class III heart failure, ejection fraction 35%, and QRS 120 ms were assessed at baseline and 3 months. LV reverse remodeling was measured by real-time 3-dimensional echocardiography. Using tissue Doppler imaging, the peak systolic velocity (Sm) and peak early diastolic velocity (Em) were calculated for LV function, while the standard deviation of the time to peak systolic velocity (Ts-SD) and the time to peak early diastolic velocity (Te-SD) were calculated for mechanical dyssynchrony.

Prospective, multicentre validation of a simple, patient-operated electrocardiographic system for the detection of arrhythmias and electrocardiographic changes.

Abstract: Aims Electrocardiographic changes, e.g. arrhythmias causing syncope or palpitations, are often transient and therefore difficult to diagnose. Systematic and symptom-activated ECG recordings can increase diagnostic yield in such patients. We evaluated the diagnostic accuracy of a simple, leadless, patient-operated ECG device compared with a standard 12-lead ECG. Methods and results We recorded a standard 12-lead surface ECG and a patient-activated ECG in direct succession in 508 consecutive patients enrolled in four centres. All ECGs were analysed by a single, blinded observer. ECGs were analysable in 505 (99.4%) patients (66% male, age 61 ± 15 years, and body mass index 27 ± 4). Analysis of the patient-activated ECG adequately detected a normal ECG (sensitivity 91% and specificity 95%), atrial fibrillation (AF) (sensitivity 99% and specificity 96%), and even T-wave abnormalities (sensitivity 90% and specificity 75%). Diagnostic accuracy for atrioventricular nodal block was moderate (sensitivity 79% and specificity 99%). Continuous parameters correlated well: ( r 2 = 0.89 for heart rate, 0.83 for PR interval, 0.78 for QRS duration, and 0.89 for QTc). Conclusion Recordings made by this patient-operated ECG device allow to detect arrhythmias and other ECG changes with high accuracy compared with a standard ECG. It may help to improve accurate diagnosis of transient ECG changes such as paroxysmal AF in palpitations or other unexplained cardiac symptoms.

Left ventricular conduction delays and relation to QRS configuration in patients with left ventricular dysfunction

Abstract: Left ventricular activation delay (LVAT) >100 ms may determine response to cardiac resynchronization therapy, but its prevalence and relation to QRS configuration are unknown. QRS duration and LVAT in control subjects (n = 30) were compared with those in patients with heart failure (HF; LV ejection fraction 23 +/- 8%, n = 120) with a QRS duration or = 120 ms (left bundle branch block [LBBB(HF)], n = 54; right bundle branch block [RBBB(HF)], n = 31). LVAT was estimated by interval from QRS onset to basal inferolateral LV depolarization. In controls, QRS duration was 82 +/- 13 ms and LVAT was 55 +/- 18 ms. LVAT was always <100 ms. In patients with NQRS(HF), QRS duration (104 +/- 10 ms) and LVAT (82 +/- 22 ms) were prolonged versus controls (p <0.001). LVAT exceeded 100 ms in 8 of 35 patients. In patients with LBBB(HF), QRS duration (161 +/- 29 ms) and LVAT (136 +/- 33 ms) were prolonged compared with controls and patients with NQRS(HF) (p <0.001). LVAT exceeded 100 ms in 47 of 54 patients. In patients with RBBB(HF), QRS duration did not differ from that in patients with LBBB(HF), but LVAT (100 +/- 24 ms) was shorter (p <0.001). In 17 of 31 patients with RBBB(HF) LVAT was <100 ms (82 +/- 12), similar to those with NQRS(HF) (p = NS), indicating no LV conduction delay. However, in 7 of 31, LVAT (135 +/- 13 ms) was similar to that in patients with LBBB(HF) (p = NS). LVAT correlation with QRS duration varied (control p = 0.004, NQRS(HF) p = 0.15, RBBB(HF) p = 0.01, LBBB(HF) p <0.001). In conclusion, LV conduction delays in patients with HF varied with QRS configuration and duration, exceeding 100 ms in only 23% of patients with narrow QRS configuration and 45% with RBBB(HF) compared with 87% with LBBB(HF). Fewer than 25% of patients with RBBB(HF) demonstrated delays equivalent to those in patients with LBBB(HF.) These variations may affect efficacy to cardiac resynchronization therapy.

System and Method for Distinguishing Between Hypoglycemia and Hyperglycemia Using an Implantable Medical Device

Abstract: Techniques are described for detecting and distinguishing among ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. In one technique, these conditions are detected and distinguished based on an analysis of: the interval between the QRS complex and the peak of a T-wave (QTmax), the interval between the QRS complex and the end of a T-wave (QTend), alone or in combination with a change in ST segment elevation. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo/hyperglycemia can be properly distinguished from changes caused by cardiac ischemia. In another technique, hyperglycemia and hypoglycemia are predicted, detected and/or distinguished from one another based on an analysis of the amplitudes of P-waves, QRS-complexes and T-waves within the IEGM. Appropriate warning signals are delivered and therapy is automatically adjusted.

Micro-Electrocardiograms to Study Post-Ventricular Amputation of Zebrafish Heart

Abstract: The zebrafish (Danio rerio) is an emerging model for cardiovascular research. The zebrafish heart regenerates after 20% ventricular amputation. However, assessment of the physiological responses during heart regeneration has been hampered by the small size of the heart and the necessity of conducting experiments in an aqueous environment. We developed a methodology to monitor a real-time surface electrocardiogram (ECG) by the use of micro-electrodes, signal amplification, and a low pass-filter at a sampling rate of 1 kHz. Wavelet transform was used to further remove ambient noises. Rather than paralyzing the fish, we performed mild sedation by placing the fish in a water bath mixed with MS-222 (tricane methanesulfonate). We recorded distinct P waves for atrial contraction, QRS complexes for ventricular depolarization, and QT intervals for ventricular repolarization prior to, and 2 and 4 days post-amputation (dpa). Sedation reduced the mean fish heart rate from 149 ± 18 to 90 ± 17 beats/min. The PR and QRS intervals remained unchanged in response to ventricular apical amputation (n = 6, p > 0.05). Corrected QT intervals (QTc) were shortened 4 dpa (n = 6, p < 0.05). In a parallel study, histology revealed that apical thrombi were replaced with fibrin clots and collagen fibers. Atrial arrhythmia was noted in response to prolonged sedation. Unlike the human counterpart, ventricular tachycardia or fibrillation was not observed in response to ventricular amputation 2 and 4 dpa. Taken together, we demonstrated a minimally invasive methodology to monitor zebrafish heart function, electrical activities, and regeneration in real-time.

Electrocardiograms of Collegiate Football Athletes

Abstract: Background The prevalence of electrocardiogram (ECG) abnormalities in American collegiate football athletes is virtually unknown. Purpose The purpose of this study was to characterize the type and frequency of ECG abnormalities in a sample of football athletes entering National Collegiate Athletic Association (NCAA) Division I Football Bowl Subdivision university program. Methods Over a 4-y period, resting and exercise 12-lead ECG recordings were analyzed by a cardiologist from 68 freshmen and 9 transfer football athletes (n=77; 54 African-Americans and 23 Caucasians, aged 18 ± 1 y, height=1.89 ± 0.06 m, weight= 104.4 ± 19.8 kg) as part of their entry physical examination. Results A total of 79% of the athletes demonstrated at least 1 abnormal ECG finnding, and significantly more African-America athletes (85%) than Caucasian (65%) athletes. Wolff-Parkinson-White (WPW) syndrome was found in 1 African-American player. Frequencies of various ECG abnormal findings in all athletes were: left ventricular hypertrophy = 64.5%, ST-T wave = 6.5%, interventricular conduction delay = 2.6%, sinus bradycardia = 9.1%, sinus arrhythmia = 15.6%, first-degree atrioventricular (AV) block = 11.7%, left atrial enlargement = 48.1%, early repolarization = 33.8%, and right axis deviation = 20.8%. Average values for the PR (0.17 ± 0.03 s), QRS (0.08 ± 0.02 s), and QT intervals (0.38 ± 0.05 s), P-wave duration (0.10 ± 0.02 s), and QRS axis (79.1 ± 18.2 degrees) were normal. The ECG responses to maximal treadmill exercise stress tests were evaluated as normal without ischemia or arrhythmias. Conclusion Abnormal resting ECG findings are common in a sample of collegiate football athletes, exceeding the rate expected for their age, and are more frequent in African-American athletes as compared with Caucasian athletes. Copyright © 2009 Wiley Periodicals, Inc.

The relationship between disease-related characteristics and conduction disturbances in ankylosing spondylitis.

Abstract: Objectives: Ankylosing spondylitis (AS) is associated with an increased cardiovascular (CV) risk. Conduction disturbances (CD) may explain the CV burden, as they are independently associated with cardiac disease. The aim of this study was (i) to determine the prevalence of CD in AS, and (ii) to evaluate the relationship between CD and demographic and AS-related characteristics.Methods: A rheumatological evaluation assessing demographic and AS-related characteristics and a resting standard 12-lead electrocardiogram (ECG) were performed in 131 consecutive AS patients.Results: A first-degree atrioventricular (AV) block was found in six (4.6%) patients. One (0.8%) patient suffered from a complete right bundle branch block (RBBB) and one (0.8%) patient had a left anterior hemiblock. A prolonged QRS (pQRS) interval was observed in 38 (29.2%) patients, including those with a complete or incomplete BBB. Age, disease duration, and body mass index (BMI) were significantly associated with the PR interval, and male g...

QRS duration predicts sudden cardiac death in hypertensive patients undergoing intensive medical therapy: the LIFE study.

Abstract: Aims To determine whether QRS duration predicts sudden cardiac death (SCD) in patients with left ventricular hypertrophy and treated hypertension. Methods and results Over 4.8 ± 0.9 years follow-up of 9193 hypertensive patients with electrocardiographic evidence of LVH who were treated with atenolol- or losartan-based regimens, 178 patients (1.9%) suffered SCD. In multivariable analysis including randomized treatment, changing blood pressure over time, and baseline differences between patients with and without SCD, QRS duration was independently predictive of SCD (HR per 10 ms increase = 1.22, P < 0.001). Baseline QRS duration remained a significant predictor of SCD even after controlling for the presence or absence of left bundle branch block (HR = 1.17, P = 0.001) and for changes in ECG LVH severity over the course of the study (HR = 1.16, P = 0.017). Conclusion In the setting of aggressive antihypertensive therapy, prolonged QRS duration identifies hypertensive patients at higher risk for SCD, even after controlling for left bundle branch block, other known risk factors for SCD, and changes in blood pressure and severity of left ventricular hypertrophy.

Short-Term Hemodynamic Effects of Cardiac Resynchronization Therapy in Patients With Heart Failure, a Narrow QRS Duration, and No Dyssynchrony

Abstract: Background— Cardiac resynchronization therapy produces both short-term hemodynamic and long-term symptomatic/mortality benefits in symptomatic heart failure patients with a QRS duration >120 ms. This is conventionally believed to be due principally to relief of dyssynchrony, although we recently showed that relief of external constraint to left ventricular filling may also play a role. In this study, we evaluated the short-term hemodynamic effects in symptomatic patients with a QRS duration <120 ms and no evidence of dyssynchrony on conventional criteria and assessed the effects on contractility and external constraint. Methods and Results— Thirty heart failure patients (New York Heart Association class III/IV) with a left ventricular ejection fraction ≤35% who were in sinus rhythm underwent pressure-volume studies at the time of pacemaker implantation. External constraint, left ventricular stroke work, dP/dtmax, and the slope of the preload recruitable stroke work relation were measured from the end-dias...

Comparison of functional status, electrocardiographic, and echocardiographic parameters to mortality in endomyocardial-biopsy proven cardiac amyloidosis.

Abstract: Cardiac amyloidosis (CA) is generally associated with a poor prognosis and significantly increased mortality. We sought to identify predictors of longer-term survival in patients with endomyocardial biopsy (EMB)-documented CA. Forty-five consecutive patients with EMB-documented CA were studied from January 1998 to December 2003. Age, gender, New York Heart Association class, medications, presence of light-chain amyloid, and electrocardiographic voltage were recorded. Baseline left ventricular (LV) ejection fraction, deceleration time, diastolic function, LV mass, ventricular septal thickness, and myocardial performance index ([isovolumic contraction time + isovolumic relaxation time]/ejection time) were recorded. Mean age was 66 +/- 10 years with 34 men (76%). New York Heart Association class >II was noted in 26 patients (58%) and low voltage on electrocardiogram (S wave [lead V(1)] + R wave [lead V(5)] 0.6 in 15 (33%). At a median follow-up of 1.7 years, there were 25 deaths (56%). On univariate Kaplan-Meier analysis, New York Heart Association class >II, deceleration time <150 ms, and beta-blocker use were associated with increased mortality (log-rank statistic p values <0.001, <0.05, and 0.01, respectively). On Cox proportional hazard survival analysis, only New York Heart Association class was significantly associated with increased mortality (hazard ratio 3.92, 1.92 to 7.95, p = 0.0002). In conclusion, in patients with EMB-documented CA, longer-term survival is more strongly associated with New York Heart Association functional class compared with electrocardiographic and echocardiographic variables.

Electrocardiogram changes and arrhythmias in venlafaxine overdose.

Abstract: WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • The major clinical effects of venlafaxine overdose are seizures and serotonin toxicity. • There is controversy over the risk of cardiac toxicity in venlafaxine overdose. WHAT THIS STUDY ADDS • Venlafaxine overdose is unlikely to cause clinically significant cardiac toxicity, including QT prolongation or malignant arrhythmias, and the commonest cardiovascular effects are tachycardia and mild hypertension. • Massive ingestions >8 g may result in cardiac toxicity and patients should be observed carefully. AIMS To investigate serial electrocardiogram (ECG) parameters, haemodynamic changes and arrhythmias following venlafaxine overdose. METHODS The study included 369 venlafaxine overdoses in 273 patients presenting to a toxicology unit where an ECG was available. Demographic information, details of ingestion, haemodynamic effects [heart rate and blood pressure (BP)] and complications (arrhythmias and conduction defects) were obtained. ECG parameters (QT, QRS) were measured manually and analysed by visual inspection, including plotting QT–HR pairs on a QT nomogram. RESULTS The median ingested dose was 1500 mg [interquartile range (IQR) 600–3000 mg; range 75–13 500 mg). Tachycardia occurred in 54% and mild hypertension (systolic BP >140 mmHg) in 40%. Severe hypertension (systolic BP >180 mmHg) and hypotension (systolic BP <90 mmHg) occurred in 3% and 5%, respectively. No arrhythmias occurred based on continuous telemetry, and conduction defects were found in only seven of 369 admissions; five of these conduction defects were pre-existing abnormalities. In 22 admissions [6%, 95% confidence interval (CI) 4–10] there was an abnormal QT–HR pair, with larger doses being more likely to be associated with an abnormal QT. The median maximum QRS width was 85 ms (IQR 80–90 ms; range 70–145 ms) and the QRS was greater than 120 ms in only 24 admissions (7%, 95% CI 4–10). CONCLUSIONS Venlafaxine overdose causes only minor abnormalities in the QT and QRS intervals, unlikely to be associated with major arrhythmias, except possibly with large doses.