Sudden Cardiac Death Prediction in Chronic Heart Failure Patients by Periodic Repolarization Dynamics

Abstract

Chronic heart failure (CHF) is a clinical syndrome associated with high mortality due to pump failure death (PFD) resulting from heart failure progression as well as to ventricular arrhythmias leading to sudden cardiac death (SCD). CHF involves autonomic nervous system imbalance, which is expected to be reflected in the electrocardiogram (ECG). Periodic Repolarization Dynamics (PRD) quantifies low-frequency oscillations in the T wave of the ECG and has been related to sympathetic modulation of ventricular repolarization. We assessed the capacity of PRD to predict PFD and SCD in a CHF population. 3-lead ECG recordings of 569 patients with symptomatic CHF were analyzed. PRD values were measured by analyzing 5-minute segments with 4-minute overlap. The minimum PRD value over the analyzed segments was assigned to each patient. PRD was higher in SCD victims than in PFD victims and than in survivors and non-cardiac death victims, although differences were not statistically significant. Low- and high-risk groups were defined by dichotomization according to median PRD in the population. Hazard ratio [95% Confidence Interval] for SCD from univariate Cox regression was 1.808 [1.031-3.169] deg (p=0.039). In conclusion, high PRD predicts SCD in a CHF population, with SCD victims presenting enhanced sympathetic-induced oscillations of ventricular repolarization.