AimsTo determine whether risk stratification tests can predict serious arrhythmic events after acute myocardial infarction (AMI) in patients with reduced left ventricular ejection fraction (LVEF ≤ 0.40).Methods and resultsA total of 5869 consecutive patients were screened in 10 European centres, and 312 patients (age 65 ± 11 years) with a mean LVEF of 31 ± 6% were included in the study. Heart rate variability/turbulence, ambient arrhythmias, signal-averaged electrocardiogram (SAECG), T-wave alternans, and programmed electrical stimulation (PES) were performed 6 weeks after AMI. The primary endpoint was ECG-documented ventricular fibrillation or symptomatic sustained ventricular tachycardia (VT). To document these arrhythmic events, the patients received an implantable ECG loop-recorder. There were 25 primary endpoints (8.0%) during the follow-up of 2 years. The strongest predictors of primary endpoint were measures of heart rate variability, e.g. hazard ratio (HR) for reduced very-low frequency component (<5.7 ln ms2) adjusted for clinical variables was 7.0 (95% CI: 2.4–20.3, P < 0.001). Induction of sustained monomorphic VT during PES (adjusted HR = 4.8, 95% CI, 1.7–13.4, P = 0.003) also predicted the primary endpoint.ConclusionFatal or near-fatal arrhythmias can be predicted by many risk stratification methods, especially by heart rate variability, in patients with reduced LVEF after AMI.
This study found that the prevalence of CRT DRI is close to 4.3% at 2.6 years (1.7% per year incidence). Four independent predictive factors of infections were identified including re-intervention, procedure time, dialysis, and primo CRT-ICD implantation. These parameters should be part of the risk-benefit evaluation in patients selected for CRT implantation.
Background-The reentrant mechanism of postinfarct ventricular tachycardia (VT) has been documented by surgical mapping analysis, but little is known about postinfarct VT circuits and the characteristics of their related protected isthmus with the use of 3D catheter mapping systems. Methods and Results-A 3D electroanatomic mapping was performed in 21 patients with well-tolerated, postinfarct, sustained VT. In total, 33 episodes of tachycardia (mean cycle length 432Ϯ74 ms) were induced and mapped. Complete maps demonstrated macroreentrant circuits with 1 loop (nϭ8) or 2 loops (nϭ25) rotating around a protected isthmus bounded by 2 approximately parallel conduction barriers that consisted of a line of double potentials, a scar area, or the mitral annulus. A total of 26 critical isthmi were identified for the 33 VTs mapped, with the same isthmus being shared by 2 to 4 different tachycardic morphologies in 5 patients. On average, isthmi were 31Ϯ7 mm long (ranging from 18 to 41 mm) and 16Ϯ8 mm wide (ranging from 6 to 36 mm) and harbored diastolic electrograms. The isthmus axis was oriented parallel to the mitral annulus plane in perimitral circuits and perpendicular to the mitral annulus plane in all other circuits. Linear radiofrequency ablation performed across the most accessible part of the isthmus prevented the recurrence of tachycardia in 19 patients (90%) with a follow-up at 16Ϯ8 months. Conclusions-Detailed
for the Cardiac Arrhythmias and Risk Stratification After Acute Myocardial Infarction (CARISMA) Study Group Background-Knowledge about the incidence of cardiac arrhythmias after acute myocardial infarction has been limited by the lack of traditional ECG recording systems to document and confirm asymptomatic and symptomatic arrhythmias. The Cardiac Arrhythmias and Risk Stratification After Myocardial Infarction (CARISMA) trial was designed to study the incidence and prognostic significance of arrhythmias documented by an implantable cardiac monitor among patients with acute myocardial infarction and reduced left ventricular ejection fraction. Methods and Results-A total of 1393 of 5869 patients (24%) screened in the acute phase (3 to 21 days) of an acute myocardial infarction had left ventricular ejection fraction Յ40%. After exclusions, 297 patients (21%) (meanϮSD age, 64.0Ϯ11.0 years; left ventricular ejection fraction, 31Ϯ7%) received an implantable cardiac monitor within 11Ϯ5 days of the acute myocardial infarction and were followed up every 3 months for an average of 1.9Ϯ0.5 years. Predefined bradyarrhythmias and tachyarrhythmias were recorded in 137 patients (46%); 86% of these were asymptomatic. The implantable cardiac monitor documented a 28% incidence of new-onset atrial fibrillation with fast ventricular response (Ն125 bpm), a 13% incidence of nonsustained ventricular tachycardia (Ն16 beats), a 10% incidence of high-degree atrioventricular block (Յ30 bpm lasting Ն8 seconds), a 7% incidence of sinus bradycardia (Յ30 bpm lasting Ն8 seconds), a 5% incidence of sinus arrest (Ն5 seconds), a 3% incidence of sustained ventricular tachycardia, and a 3% incidence of ventricular fibrillation. Cox regression analysis with time-dependent covariates revealed that high-degree atrioventricular block was the most powerful predictor of cardiac death (hazard ratio, 6.75; 95% confidence interval, 2.55 to 17.84; PϽ0.001). Conclusions-This is the first study to report on long-term cardiac arrhythmias recorded by an implantable loop recorder in patients with left ventricular ejection fraction Յ40% after myocardial infarction. Clinically significant bradyarrhythmias and tachyarrhythmias were documented in a substantial proportion of patients with depressed left ventricular ejection fraction after acute myocardial infarction. Intermittent high-degree atrioventricular block was associated with a very high risk of cardiac death. Clinical Trial Registration-URL: http://www.ClinicalTrials.gov, Unique identifier: NCT00145119.
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