We must identify patients at risk for pre-hospital sudden cardiac arrest at the early phase of myocardial infarction

Abstract

Global coronary heart disease mortality has markedly decreased for the last 4 decades thanks to primary prevention. More than half of the total reduction has been achieved by controlling cardiovascular risk factors (1). Concurrently, effective therapeutic modalities have contributed to reducing further in-hospital fatal events, obtaining a 6-8% reduction (1,2). Meanwhile, out-of-hospital sudden cardiac arrest (SCA) secondary to myocardial infarction remains high, and still represents the majority of all fatal cardiac events (3). Although there is a large amount of literature regarding this sudden and unexpected complication, there is still need for a better understanding of associated risk factors and to identify patients at highest risk for SCA at the pre-hospital phase. Early recognition of the risk of this grim complication could permit a better triage of high-risk patients and consequently improve their outcome.Concerned by the high pre-hospital mortality in STsegment-elevation myocardial infarction (STEMI), Karam et al. have recently performed a landmark study aimed at identifying characteristics of STEMI patients presenting with out-of-hospital SCA (4). Using a prospective population-based design, they included patients from the e-MUST (Evaluation en Médecine d'Urgence des Stratégies Thérapeutiques des infarctus du myocarde) registry between 2006 and 2010, which includes all the out-of-hospital STEMI patients managed by the Emergency Medical Service (EMS) in Paris area. In short, it combines data collected by the EMS dispatch call center and the EMS physician in the field. They included patients that were primarily managed by the EMS, alive at EMS arrival, with typical angina and a STEMI-compatible electrocardiogram (ECG). Pre-hospital SCA was defined as a "sudden and unexpected pulseless event without obvious extracardiac cause occurring before hospital arrival and witnessed by the EMS". Patients with SCA prior to EMS arrival were excluded because of ECG's poor predictive value for STEMI diagnosis after resuscitation.Eight thousand one hundred and twelve STEMI patients {median age [interquartile range]: 60 years, 78% male} were managed by the EMS within 60 [26-165] minutes after pain onset. Four hundred and fiftytwo patients (5.6%) presented EMS-witnessed out-ofhospital SCA, with ventricular tachycardia or ventricular fibrillation as the most frequent initial rhythms (348 patients, 76.9%). Survival in this population was 63.9%, which was significantly lower than reported in the non-SCA population (95.9%). SCA patients with complete data were randomly split into two cohorts, namely a derivation cohort (two thirds of the population) and a validation cohort (one third of the population). From the derivation cohort, pre-hospital risk factors of SCA were Editorial

Incidence and predictors of sudden cardiac arrest in the immediate post-percutaneous coronary intervention period for ST-elevation myocardial infarction: a single-center study

“…Notably, OHCA was the most significant predictor of SCA in the immediate post-PCI period for STEMI. The association of OHCA and poor outcomes in STEMI has previously been described [12–14,19,22,23]. In the e-MUST study, investigating the incidence and prognosis of pre-hospital SCA among STEMI patients and patients with OHCA from STEMI were nine times more likely to die compared to the non-OHCA group [14].…”