Predictors and Prognostic Significance of Appropriate Implantable Cardioverter-Defibrillator Therapy in Primary...

Background: In the population of patients with ischemic cardiomyopathy (IC) and reduced left ventricular ejection fraction, the benefits of prophylactic implantable cardioverter-defibrillator (ICD) therapy are not uniform. Identifying predictors of ventricular arrhythmias to estimate the risk of appropriate therapy is crucial. Methods: Patients with IC and an ICD for primary prevention implanted between 2006 and 2019 were retrospectively analyzed for appropriate therapy (ATh). The primary objective was to assess predictors of ATh development. The secondary objective was to assess the impact of ATh on survival. Results: Overall, 260 patients (age 67.3 ± 9.4 years, 15.4% female) were analyzed with a follow-up of 4.47 ± 3.02 years. ATh occurred in 79 patients (30.4% of the study group). Independent risk factors for ATh were as follows: non-sustained ventricular tachyarrhythmias (nsVTs) detected before ICD implantation, extensive area of ischemic left ventricular damage on echocardiographic assessment, left ventricular end-diastolic dimension (LVEDd) ≥ 68 mm, history of coronary artery bypass grafting (CABG), and presence of chronic total occlusion (CTO). A multiparameter logit model was created to estimate the probability of ATh. Patients with a score ≥ 0.6 had more than a six-fold higher risk of developing ATh compared with patients with a score < 0.6. Patients after ATh had significantly lower survival compared to patients without intervention (HR 1.69, p = 0.008). Conclusions: Patients with the independent risk factors listed above are at higher risk for ATh. A multiparameter logit model based on these risk factors is effective in estimating the risk of ATh. The occurrence of ATh was associated with a significantly higher risk of all-cause mortality.