Predictors of ventricular tachyarrhythmia in patients with implantable cardioverter-defibrillator and non-ischemic systolic heart failure.

Background: The benefit derived from implantable cardioverter-defibrillators (ICD) in subjects with non-ischemic systolic HF (NICM) is less well-established.
Aim: The study aimed to determine the incidence, predictors, and prognostic impact of ventricular arrhythmias in patients with ICD and NICM.
Methods: The study sample included 377 consecutive patients with ICD or cardiac resynchronization cardioverter-defibrillators (CRT-D, 74% of patients) and NICM implanted and monitored remotely in a university hospital.
Results: During the median (interquartile range [IQR]) follow-up of 1645 (960-2675) days, sustained ventricular arrhythmia occurred in 92 patients (24.4%). Of those, ventricular fibrillation (VF), ventricular tachycardia (VT), and both VT and VF occurred in 10 (10.9%), 72 (78.3%), and 10 (10.9%) patients, respectively. Patients with vs. those without ventricular arrhythmia differed concerning sex, left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular ejection fraction (LVEF), post-inflammatory etiology, atrial fibrillation/flutter occurrence, and supraventricular arrhythmia (SVT) other than AF/AFL during follow-up. In multivariable Cox regression, LVEDD (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.003-1.09; P = 0.03), AF/AFL (HR, 1.86; 95% CI, 1.21-2.85; P = 0.004), and SVT (HR, 1.77; 95% CI, 1.10-2.87; P = 0.02) were independent predictors of sustained VT, while AF/AFL (HR, 1.65; 95% CI, 1.07-2.56; P = 0.02) was independent predictor of VF. All-cause mortality in patients with VT/VF was significantly higher than in subjects without sustained ventricular arrhythmias (35.9% vs. 22.4%; P = 0.01).
Conclusions: Ventricular arrhythmia occurred in every fourth patient with NICM and ICD during 4.5 years of observation and was associated with significantly worse prognosis than in subjects free of VT/VF. Higher LVEDD, atrial fibrillation/atrial flutter, and supraventricular tachycardia flag patients at risk of ventricular arrhythmia.