Gap between guideline-based indications and real-world implementation of wearable cardioverter-defibrillators after acute myocardial infarction

BACKGROUND: To prevent sudden cardiac death after acute myocardial infarction (AMI), current guidelines recommend the use of a wearable cardioverter-defibrillator (WCD) as bridging therapy before implantable cardioverter-defibrillator implantation in patients with left ventricular ejection fraction ≤35% and New York Heart Association class ≥ II at discharge. However, real-world data regarding the implementation of guideline-based indications for WCD therapy-and the reasons for their underuse-remain limited in Japan. PURPOSE: This study aimed to evaluate the gap between guideline-based indications and real-world implementation of WCD therapy after AMI, and to identify physician- and system-related barriers contributing to WCD underuse. METHODS AND RESULTS: We analyzed data from the SING (Shizuoka Catheter INtervention Group)-AMI registry, a prospective multicenter cohort of patients with AMI who underwent primary percutaneous coronary intervention at seven hospitals in Shizuoka Prefecture, Japan. Among 229 patients (mean age, 70.7 years; 76.3% male), 15 sustained ventricular arrhythmia events (ventricular tachycardia/ventricular fibrillation [VT/VF]) occurred in 15 patients (6.6%) during hospitalization. At discharge, 12 patients (5.2%) met guideline-based WCD eligibility; however, no WCDs were prescribed. Although physicians identified 10 patients as WCD candidates, 8 were misclassified due to misinterpretation of eligibility criteria. Furthermore, WCD use was not discussed with 19 of 20 eligible or potentially eligible patients, primarily due to lack of recognition of eligibility, limited physician familiarity, or patient-related concern. CONCLUSIONS: In this prospective Japanese registry, 5.2% of AMI patients met guideline-based indications for WCD therapy; however, no WCDs were prescribed. While these findings are limited by the small sample size, they suggest a potential gap between clinical guidelines and their implementation in real-world practice.