Tachycardia Therapy Outcomes of Ischemic Versus Nonischemic Cardiomyopathy on Cardiac Resynchronization Therapy: A Propensity Score-matched Analysis

Objective: This investigation aimed to investigate differences between dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) patients treated with cardiac resynchronization therapy with defibrillator (CRT-D) for tachy-cardia therapy-related outcomes as well as mortality during follow-up of at least 1 year. Methods: Seventy-eight patients with DCM (n = 42) and ICM (n = 36) with implantation or upgradation to CRT-D were included in this study and analyzed for incidence of non-sustained ventricular tachycardia (NSVT), non-sustained ventricular fibrillation (NSVF), defibrillator therapies, anti-tachycardia pacing (ATP), and mortality. Results: DCM was the underlying etiology in 42 (53.84%) and ICM in 36 (46.15%). Time to first therapy was numerically longer in DCM than in ICM (9.5 +/- 2.4 vs. 7.1 +/- 3.2; P-value = 0.088). DCM patients had significantly higher therapy-free survival and mortality compared with ICM patients (OR (95%CI): 0.238 (0.155-0.424); log-rank P = 0.017) and (OR (95% CI): 0.612 (0.254-0.924); log-rank P = 0.029). ICM (HR (95%CI): 0.529 (0.243-0.925); P-value = 0.014) CAD (HR (95%CI): 0.326 (0.122-0.691): P-value = 0.003), and NSVT (HR (95%CI): 0.703 (0.513-0.849): P-value = 0.005) were demonstrated as independent predictors of the primary endpoint of appropriate therapy in CRT-D and ICM (HR (95%CI): 0.421 (0.321-0.524); P-value = 0.037), chronic kidney disease (CKD; HR (95%CI): 0.289 (0.198-0.380); P-value = 0.013), and CAD (HR (95%CI): 0.786 (0.531-0.967); P-value = 0.003) were predictors of mortality. Conclusion: The clinical course of ICM and DCM cohorts who were treated with CRT-D differs significantly during follow-up, with increased tachycardia therapy and increased incidence of mortality in ICM patients.