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

Abstract

Objective: This 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%).

Background: The prediction of cause-specific mortality in high-risk patients offers the potential for targeting specific therapies (i.e., implantable cardioverter-defibrillator [ICD]).

Methods: Subjects 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).

Results: Among 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.

Conclusions: Among 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.

Keywords: Electrocardiogram; Implantable cardioverter defibrillator; Ischemic cardiomyopathy; Sudden cardiac arrest.

Copyright © 2014 Elsevier Inc. All rights reserved.

Figures

Figure 1. Prevalence of High Risk ECG Parameters

An illustration of the prevalence of high-risk ECG parameters within the groups. Refer to Table 2 for abbreviations.

Figure 2. Probability Curves for Predicting Sudden Cardiac Arrest and Cardiac Non-Sudden Death

Panel 1: Kaplan-Meier events probability curves showing that QTc interval (≥ 440 ms), not HRV or persistent pacing, predicts sudden cardiac arrest or the equivalent. Panel 2: Kaplan-Meier events probability curves showing that HRV (SDNN