Non-ischemic compared to ischemic cardiomyopathy is associated with increasing recurrent ventricular tachyarrhythmias and ICD-related therapies.

Objective: The study sought to assess the impact of ischemic (ICMP) compared to non-ischemic cardiomyopathy (NICMP) on recurrences of ventricular tachyarrhythmias in implantable cardioverter defibrillator (ICD) recipients.
Background: Data comparing recurrences of ventricular tachyarrhythmias in ICD recipients with ischemic or non-ischemic cardiomyopathy is limited.
Methods: A large retrospective registry was used including all consecutive ICD recipients with first episodes of ventricular tachycardia (VT) or fibrillation (VF) from 2002 to 2016. Patients with ICMP were compared to patients with NICMP. The primary prognostic endpoint was first recurrences of ventricular tachyarrhythmias at one year. Secondary endpoints comprised ICD-related therapies, rehospitalization and all-cause mortality at one year. Statistics Kaplan-Meier survival and multivariable Cox regression analyses.
Results: A total of 387 consecutive ICD recipients were included retrospectively (ICMP: 82%, NICMP: 18%). At one year of follow-up, freedom from first recurrences of ventricular tachyarrhythmias was lower in NICMP (81% vs. 71%, log-rank p = 0.063; HR = 1.760; 95% CI 0.985-3.002; p = 0.080), mainly attributed to higher rates of sustained VT (20% versus 12%, p = 0.054). Accordingly, freedom from first appropriate device therapies was lower in NICMP (74% vs. 85%, log rank p = 0.004; HR = 1.951; 95% CI 1.121-3.397; p = 0.028), especially in patients with sustained VT or VF at index. Both groups revealed comparable rates of rehospitalization and all-cause mortality at one year.
Conclusion: NICMP was associated with higher rates of recurrent ventricular tachyarrhythmias and appropriate ICD therapies compared to ICMP at one year of follow-up, whereas rates of rehospitalization and all-cause mortality were comparable.
Condensed Abstract: This study retrospectively compared the impact of cardiomyopathy types (ICMP versus NICMP) on recurrences of ventricular tachyarrhythmias in 387 ICD recipients. Freedom from first episodes of ventricular tachyarrhythmias and first appropriate device therapies were lower in patients with NICMP compared to ICMP.
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