Sudden cardiac arrest: ECG repolarization after resuscitation.

Introduction: Early repolarization (ERep) abnormalities on electrocardiogram (ECG) are common immediately following cardiac arrest. We characterized and correlated electrocardiographic repolarization abnormalities immediately after cardiac arrest with acute coronary angiography.

Methods And Results: We studied 225 consecutive patients presenting with out-of-hospital cardiac arrest. All these patients had successful cardiopulmonary resuscitation and acute coronary angiography. The first ECG recorded after successful resuscitation was analyzed by two independent cardiologists. Patients were categorized according to their repolarization pattern. Pattern 1: No ST segment elevation or ERep. Pattern 2: ST segment elevation without ERep. Pattern 3: ST segment elevation and ERep. Pattern 4: ERep only. Patterns 1, 2, 3, and 4 were found in 112 (50%), 74 (33%), 19 (8%), and 20 (9%) patients, respectively. Cardiac arrest was due to acute myocardial ischemia in 45%, 82%, 39%, and 15% of patients in groups 1, 2, 3 and 4, respectively (P < 0.0001). Sensitivity and specificity of pattern 2 was 50% and 88%, respectively, for acute coronary lesion, whereas isolated ERep pattern occurred in 9% of cases and was associated with a nonischemic event (80%). Among 65 patients (29%) who survived, 7% of patients with pattern 1, 13% with pattern 2, 60% with pattern 3, and 88% with pattern 4 exhibited ERep on ECG during the follow-up.

Conclusion: In the context of cardiac resuscitation, an ECG with ST elevation favors acute myocardial infarction, whereas the presence of ERep is a marker of a nonischemic event and future ERep syndrome.