Incidence of sustained ventricular tachyarrhythmias in patients with non-ischemic cardiomyopathy in a multicenter multinational WCD cohort

Abstract

Abstract Background Defibrillator use in patients with non-ischemic cardiomyopathy (NICM) and HFrEF remains controversial after the DANISH study. The new ESC guidelines recommend individualized risk stratification in these patients. The wearable cardioverter-defibrillator (WCD) seems to be appropriate to both protect and screen patients with HFrEF at risk for sudden cardiac death (SCD). Puropose: To evaluate the rate of ventricular tachyarrhythmias (VT/VF) in NICM vs. ICM patients receiving a WCD for temporary SCD protection. Methods 1157 patients were included in a multicenter registry from eight European centers. Among these patients, 602 patients received a WCD due to ischemic cardiomyopathy (ICM) and 555 patients for non-ischemic cardiomyopathy (NICM). Incidence of VT/VF and/or appropriate WCD shock discharge during WCD use were evaluated. The mean follow-up (FU) time of the whole cohort was 620.2±607.8 days. Results NICM patients were younger (mean 56.5±14.8a vs 63.9±11.6a; p<0.001) and less often male (75% vs. 87.2%; p<0.001) compared to ICM patients. Heart failure medication at hospital discharge did not differ between the two groups except for a higher prescription rate of aldosterone-antagonists in NICM compared to ICM patients (73.8% vs. 66.7%; p=0.02). The index left ventricular ejection fraction (LVEF) was significantly lower in NICM compared to ICM patients (mean 26.1±9.1% versus 29.5±9.2%; p<0.001). A larger extent of LVEF recovery was detected in NICM patients compared to ICM patients up to the end of WCD use (mean LVEF post WCD: 45.7±35.4% vs. 40.2±11.8%; p=0.02). Average daily WCD wear-time was significantly lower in NICM patients compared to ICM patients (mean 20.7±4.9h vs. 21.6±3.7h; p=0.01). NICM patients had a significantly lower incidence of sustained ventricular tachyarrhythmia (VT/VF) compared to ICM patients (3.4% vs. 6.6%; p=0.02). Consistently, rate of appropriate WCD shock was significantly lower in NICM vs. ICM patients (0.7% vs. 3.7%; p< 0.001), as was rate of re-hospitalization (30.2% vs. 46.1%; p<0.001). Both groups showed a similar mortality rate during FU. Conclusions Patients at risk for SCD with NICM showed a more pronounced LVEF recovery, significantly lower incidence of VT/VF with concomitant shocks and hospitalization, while overall mortality was unchanged compared to ICM patients. These results indicate that WCD use might facilitate individual SCD risk stratification in NICM patients.