Strategies for Reducing Sudden Cardiac Death by Raising Public Awareness　― A Statement From the Education and Implementation for Cardiac Emergency Committee of the Japanese Circulation Society ―

1.2 Cases of OHCA Caused by ACS 1.2.1 Current Status of OHCA Caused by ACS CAD has emerged as the primary reversible cause among OHCA patients with shockable rhythms, such as ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT). 12,13Acute coronary occlusion accounts for >85% of cases with ST-segment elevation (STE) on electrocardiography (ECG), regardless of shockable rhythms. 13pproximately 60-65% of OHCA patients with an initial shockable rhythm who do not achieve a return of spontaneous circulation (ROSC) have acute coronary lesions.In contrast, patients without STE exhibit a markedly lower incidence of acute coronary occlusion, regardless of shockability. 13pproximately 6-9% of patients treated with primary percutaneous coronary intervention (PCI) are reported to have concomitant OHCA. 14-16Several studies have identified risk factors for OHCA in patients with AMI, including younger age, male sex, the absence of calcium channel blocker therapy, larger infarct size, left main trunk lesion, chronic total occlusion, and a history of heart failure. 17-19Another cause of OHCA due to ACS is vasospastic angina.A questionnaire survey conducted in Japan reported that vasospastic angina was responsible for 14% of sudden deaths. 20Possible mechanisms of cardiac arrest include repolarization abnormalities caused by ischemia due to coronary spasm and the formation of myocardial scar as a result of ischemia. 21 1. Diagnosis and Treatment Strategies forResuscitated Patients With OHCA Current guidelines strongly support emergency coronary angiography (CAG) for all successfully resuscitated OHCA patients with STE on pre-or postarrest ECG and an expected reasonable neurological prognosis (Table 1). [22][23]][24] However, the benefit of immediate CAG in patients without STE on post-ROSC ECG is less clear owing to heterogeneity in study designs and findings.Although early observational studies 24a,24b suggested a possible benefit, recent randomized trials 25-27 comparing immediate and delayed angiography in patients with cardiac arrest without STE found no significant differences in survival outcomes. 25-27Collectively, these randomized trials 25-27 suggest that routine early CAG is not beneficial in patients with cardiac arrest without STE.Consequently, the latest European Society of Cardiology (ESC) guidelines published in 2023 downgraded the recommendation for early CAG from Class 2A to Class 3 for patients with resuscitated cardiac arrest without persistent STE. 22