The ECG after out-of-hospital cardiac arrest is a reliable tool to guide immediate triage? Analysis of 88 patients matched with acute coronary angiography

Abstract

Background: In comatose patients resuscitated (ROSC) after out-of-hospital cardiac arrest (OHCA) the ECG is not considered a reliable tool to predict acute coronary-artery occlusion. Thus, immediate coronary angiography (CA) has been suggested for diagnostic and therapeutic purposes. However, CA could delay therapeutic hypothermia (TH), when indicated, and has other logistics drawbacks. Therefore, aim of the study was to evaluate in survivors of OHCA the reliability of ECG to triage to immediate or delayed CA and interventions. Methods: Observational prospective analysis of patients (pts) with ROSC after OHCA admitted alive to the Emergency Room (ER) of a tertiary center from March 27, 2004 to December 31, 2012 treated with TH and undergoing early CA and PCI. Results: We analysed 142 pts patients with ROSC after OHCA, admitted alive to our hospital, that underwent early CA (median age: 66.5 (IQR 55-74) yrs, males: 70%, shockable rhythm: 71%, interval OHCA-resuscitation ≤20 min: 69%) with at least 2 consecutive ECGs post ROSC available. 88 pts fulfilled the study criteria and ECG were analyzed from two different operators. The mean time between ROSC and the first ECG was 5±4 min. 36 pts (41%) meet the ECG criteria for ST elevated myocardial infarction (STEMI, Group A), 28 pts (32%) for subendocardial ischemia (Group B), and in 24 (27%) pts there were no ECG signs of ischemia (Group C). In the Group A at early CA 23 pts (64%) had acute coronary occlusion, 7 pts (19%) subocclusion of at least one vessel, and 6 (17%) 3 vessels disease or no lesions. 30 (83%) pts underwent successful PCI. In the Group B 7 pts (25%) underwent to PCI (1 case 100% acute occlusion of distal right coronary artery and 6 cases of stenosis 70-90%). As opposed in the Group C, no one patient had acute coronary occlusion at CA. Notably, only 1 case in the Group B and 1 case in the Group C developed elevated Troponin I (one case of myocarditis and one case ofhypertrophic cardiomyopathy, respectively). The in-hospital crude mortality of patients was 20% in Group A, 15% in Group B and 22% in Group C; 60% of survivors were discharged with a good neurological outcome. Conclusions: Our preliminary data suggest that a simple ECG after ROSC in OHCA survivors could be a good predictor for acute coronary occlusion. Therefore, ST elevation cases could be triage to immediate CA (Group A), in the presence of ECG ischemia the CA can be considered (Group B), while in the absence of ECG ischemia CA could be delayed (Group C). These findings, if confirmed by adequately sized studies, could simplify the triage of ROSC pts after OHCA to CA.