Abstract 14643: Benefits and Risks of Single- vs. Dual- Chamber Implantable Cardioverter Defibrillators for Primary Prevention of Sudden Cardiac Death

Introduction: Implantable cardioverter defibrillator (ICD) is the more effective and safer treatment for the primary prevention of sudden cardiac death. It remains unclear whether dual-chamber ICD offers the clinical benefits over single-chamber ICD without increasing complications. Hypothesis: The study aimed to evaluate the benefits and risks of dual-chamber ICD compared with single-chamber ICD for primary prevention of sudden cardiac death in clinical practice. Methods: Using the Korean National Health Insurance Service database from January 2008 to December 2019, we include patients with primary prevention ICD and no documented indication for pacing. The propensity score matching method was used to balance covariates across single- and dual-chamber ICDs. Primary outcomes were all-cause mortality, hospitalization of heart failure, and hospitalization of cardiovascular cause. Results: Among 1,929 patients, 1,098 (56.9%) received a single-chamber ICD and 831 (43.1%) received a dual-chamber ICD. In 752 pairs of patients after propensity matching baseline characteristics were balanced between the 2 groups (median age 62 years; male 72%). Over a mean follow-up of 2.7±2.4 years, 1- and 5-year all-cause mortality (5.5% vs. 5.6%, P=0.910; 19.4% vs. 19.3%, P=0.948), 1- and 5-year hospitalization for cardiovascular cause (14.9% vs. 14.9%, P=1.000; 23.9% vs. 22.6%, P=0.542), and 1- and 5-year hospitalization for heart failure (10.8% vs. 8.6%, P=0.163; 16.8% vs. 14.0%, P=0.133) were similar in both groups. However, cardiac tamponade in the rates of device-related complications was 0.1% in the single-chamber ICD vs. 1.1% in dual-chamber ICD groups (P=0.013). Conclusions: In the real-world population receiving a primary prevention ICD, dual-chamber ICD was associated with higher rates of cardiac tamponade than single-chamber ICD. One and five-year rates of all-cause mortality and hospitalization did not differ significantly between the two groups.