Ventricular arrhythmia events in heart failure patients with cardiac resynchronization therapy with or without a defibrillator for primary prevention

BACKGROUND: It is uncertain whether cardiac resynchronization therapy with a defibrillator (CRT‐D) provides better survival benefits than a CRT‐pacemaker (CRT‐P) in heart failure patients with a reduced ejection fraction (≦35%, HFrEF) treated with contemporary HF therapy. METHODS: We retrospectively analyzed the ventricular arrhythmia (VAs; sustained ventricular tachycardia/fibrillation) events in HFrEF patients who underwent CRT without a prior history of VAs or aborted sudden cardiac death before the CRT implantation. Between January/2010 and December/2020, a CRT device was implanted in 79 HFrEF patients (mean age: 69 ± 12 years, male: 57, ischemic cardiomyopathy: 16). CRT‐D and CRT‐P devices were implanted in 50 and 29 patients, respectively, at each physician's discretion. CRT‐Ds were indicated in younger patients than were CRT‐Ps (66 ± 12 vs. 73 ± 12 years, p = 0.03), but the gender distribution did not differ (female, 24% [12 of 50] vs. 35% [10 of 29], p = 0.44). The VA events during a median follow‐up of 3.5‐years (interquartile range [IQR]:1.6–5.5) and their predictors were analyzed. RESULTS: VA events occurred in 9 patients with CRT‐Ds (18%) and one with a CRT‐P (3%, p = 0.08). The VA event rate was significantly lower in patients without a prior non‐sustained ventricular tachycardia (NSVT: ≥3 beats; rate, ≥120 bpm; lasting <30 s, HR 0.05; 95% CI 0.01–0.30; p < 0.01) and females (HR 0.11; 95% CI 0.01–0.93; p = 0.04). Of note, no female patients without a prior history of NSVT experienced VA events. CONCLUSION: HFrEF CRT candidates without a prior history of NSVT and females may obtain less benefit from a primary preventive defibrillator indication.