Prediction of sudden cardiac death in chronic heart failure patients by analysis of restitution dispersion

An increase in the dispersion of action potential duration restitution (APDR) has been associated with higher propensity to suffer from ventricular arrhythmias and sudden cardiac death (SCD). Recently, a marker, Δα, was proposed to non-invasively quantify APDR dispersion from the electrocardiogram (ECG) by computing the ratio between differences in the T-peak-to-T-end (T_pe) and RR intervals at different steady-state conditions. Holter ECG recordings of patients with chronic heart failure divided into two groups, one consisting of victims of SCD and the other of victims of other causes and survivors, were analyzed. ECGs were delineated using a single-lead procedure over the first principal component calculated to emphasize the T-wave. Δα discriminated between the groups formed by SCD and non-SCD victims, respectively, with mean ± SEM values of: Δα = 0.052 ± 0.013 for the former and Δα = 0.026 ± 0.003 for the latter (p <; 0.048). In a survival analysis where a threshold on the third quartile of Δα values was set, statistically significantly different event probabilities were obtained in both stratas of the population (p = 0.003). The marker Δα stratifies patients according to their risk of suffering from ventricular arrhythmias that could lead to SCD, with larger restitution dispersion indicating lower survival probability.