Purpose: Risk stratification of serious arrhythmic events in patients with nonischemic heart failure (HF), beyond estimates of left ventricular ejection fraction (LVEF), remains an important clinical challenge. This study aims to determine the clinical value of different noninvasive and invasive tests as predictors of serious arrhythmic events in patients with nonischemic HF.
Methods: A prospective observational study was conducted including 106 nonischemic HF patients who underwent a comprehensive clinical and laboratory evaluation including two-dimensional echocardiography, 24-h Holter monitoring, cardiopulmonary exercise testing (CPX), and an invasive electrophysiological study. The study's primary end-point was either syncope, appropriate therapy by implantable cardioverter-defibrillators, or sudden cardiac death.
Results: During a mean follow-up of 704 ± 320 days, the primary end-point occurred in 15 patients (14.2%). In multivariable analysis, LV end-diastolic diameter >73 mm (hazard ratio [HR] 3.7; p = 0.016), exercise periodic breathing (EPB) on CPX (HR 2.88; p = 0.045), and non-sustained ventricular tachycardia (NSVT) ≥10 beats (HR 8.2; p < 0.01) remained independently associated with serious arrhythmic events. The positive predictive value of the presence of two of these predictors ranged from 44 to 100%. The absence of all three factors (n = 65, 61% of the sample) identified a subset of patients with low risk of future arrhythmic events, with a negative predictive value of 96.9%.
Conclusions: In this cohort study of nonischemic HF patients, LV dimension, EPB, and NSVT ≥10 beats were independent predictors of serious arrhythmic events. The presence or absence of these characteristics identified sub-groups of high and low risk of serious arrhythmic events, respectively.
Keywords: Arrhythmia; Heart failure; Risk stratification; Sudden cardiac death.