Electrocardiographic predictors of sudden and non-sudden cardiac death in patients with ischemic cardiomyopathy

-The ECG is a simple and valuable tool to identify patients at greater risk for adverse cardiac events-Novel approaches to analyze the ECG in the presence of interpretation confounders are needed

ObjectiveThis study evaluated the prognostic value of electrocardiogram (ECG)-based predictors in the primary prevention of sudden cardiac arrest (SCA) among ischemic cardiomyopathy patients with depressed left ventricular ejection fraction (LVEF ≤35%).BackgroundThe prediction of cause-specific mortality in high-risk patients offers the potential for targeting specific therapies (i.e., implantable cardioverter-defibrillator [ICD]).MethodsSubjects were recruited from the Prediction of Arrhythmic Events with Positron Emission Tomography (PAREPET) study. Continuous Holter 12-lead ECG recordings were obtained at the start of study and used to compute 15 clinically-important ECG abnormalities (e.g., atrial fibrillation).ResultsAmong 197 patients (age 67 ± 11 years, 93% male, mean follow-up 4.1 years) enrolled, 30 (15%) were SCA cases and 35 (18%) cardiac non-sudden deaths (C/NS). In multivariate analysis, only heart-rate-corrected QT interval (QTc) predicted SCA (hazard ratio 2.9 [1.2–7.3]) and only depressed heart rate variability (HRV) predicted C/NS (hazard ratio 5.0 [1.5–17.1]) independent of demographic and clinical parameters.ConclusionsAmong patients with depressed LVEF, prolonged QTc suggests greater potential benefit from ICD therapy to prevent SCA; depressed HRV suggests potential benefit from bi-ventricular pacing to prevent C/NS.