Characteristics and prognosis of patients with implantable cardioverter defibrillator for secondary prevention of out-of-hospital cardiac arrest due to vasospastic angina

Abstract Background Vasospastic angina (VSA) is one of major causes of out-of-hospital cardiac arrest (OHCA), especially in young patients. Implantable cardioverter-defibrillator (ICD) in addition to coronary vasodilators might be considered for secondary prevention in patients with VSA and aborted sudden cardiac death (SCD). However, consensus is lacking on the selection between subcutaneous ICD (S-ICD) or transvenous ICD (TV-ICD) for the secondary prevention with VSA. Purpose The purpose of this study was to investigate the clinical characteristics and prognosis of the VSA patients with ICD implantation as secondary prevention, and to clarify the selection of ICD type and management of ICD in the long-term follow-up. Methods Consecutive twenty-three VSA patients (20 males, 52.1 ± 12.0 years) who received ICD implantation for the secondary prevention of SCD were retrospectively evaluated between January 2011 and September 2024. Results Ventricular fibrillation was analyzed by automated external defibrillator in 22 patients (95.7%) and successfully defibrillated in 20 before hospital arrival. Two out of those 22 patients returned to sinus rhythm after additional mechanical circulation support. These cardiac events occurred during the daytime (AM6-PM6 hours) in 21 patients (91.3%) and on exertion in 5 (21.7%). TV-ICD was implanted in 14 patients and S-ICD was in 9. TV-ICD was considered preferrable to S-ICD for 3 cases. One patient suffered from not only OHCA by sustained ventricular tachycardia but also from bradycardia due to paroxysmal atrioventricular block (Figure 1). The others had dramatic ST-T changes during VSA attack (Figure2). One patient with TV-ICD had appropriate ICD shock 10 years after ICD implantation. The other patients had neither appropriate ICD shock nor syncope during median follow-up of 85.2 ± 54.8 months. Nine out of 14 patients with TV-ICD had ventricular high-rate episodes due to atrial fibrillation or sinus tachycardia, and 3 had inappropriate ICD therapies. Beta-blockers could not be used to control heart rate in these patients because of the influence of beta-blocker to VSA. Conclusions Although appropriate ICD shock is rare under strict use of vasodilators, the electrocardiogram during VSA attack may play a role for selecting TV-ICD or S-ICD. Heart rate control is crucial problem to avoid inappropriate therapies.Patient 1 Patient 2