Electrocardiographic Findings in Patients With Acute Coronary Syndrome Presenting With Out-of-Hospital Cardiac Arrest

Abstract

We sought to characterize presenting electrocardiographic findings in patients with acute coronary syndromes (ACSs) and out-of-hospital cardiac arrest (OHCA). In the Global Registry of Acute Coronary Events and Canadian ACS Registry I, we examined presenting and 24- to 48-hour follow-up ECGs (electrocardiogram) of ACS patients who survived to hospital admission, stratified by presentation with OHCA. We assessed the prevalence of ST-segment deviation and bundle branch blocks (assessed by an independent ECG core laboratory) and their association with in-hospital and 6-month mortality among those with OHCA. Of the 12,040 ACS patients, 215 (1.8%) survived to hospital admission after OHCA. Those with OHCA had higher presenting rates of ST-segment elevation, ST-segment depression, T-wave inversion, precordial Q-waves, left bundle branch block (LBBB), and right bundle branch block (RBBB) than those without. Among patients with OHCA, those with ST-segment elevation had significantly lower in-hospital mortality (20.9% vs 33.0%, p = 0.044) and a trend toward lower 6-month mortality (27% vs 39%, p = 0.060) compared with those without ST-segment elevation. Conversely, among OCHA patients, LBBB was associated with significantly higher in-hospital and 6-month mortality rates (58% vs 22%, p <0.001, and 65% vs 28%, p <0.001, respectively). ST-segment depression and RBBB were not associated with either outcome. Sixty-three percent of bundle branch blocks (RBBB or LBBB) on the presenting ECG resolved by 24 to 48 hours. In conclusion, compared with ACS patients without cardiac arrest, those with OHCA had higher rates of ST-segment elevation, LBBB, and RBBB on admission. Among OHCA patients, ST-segment elevation was associated with lower in-hospital mortality, whereas LBBB was associated with higher in-hospital and 6-month mortality.

Focused cardiac ultrasound after return of spontaneous circulation in cardiac-arrest patients

“…In OHCA patients ECG findings of LBBB and RBBB are more frequent than in patients with myocardial infarction without cardiac arrest 85 . In Study I the proportion of cases of RBBB was 12.5%, consistent with figures in other studies 85 .…”

“…In OHCA patients ECG findings of LBBB and RBBB are more frequent than in patients with myocardial infarction without cardiac arrest 85 . In Study I the proportion of cases of RBBB was 12.5%, consistent with figures in other studies 85 . Bundle-branch block is often transient in cardiac-arrest patients which could be explained by global hypoxia during the arrest, differing from the situation in patients without cardiac arrest, where a bundle branch block should increase the suspicion of a coronary culprit lesion.…”

“…In a study describing angiographic findings in relation to ECG, LBBB had the same proportion (40%) of normal coronary findings as normal ECG 84 . Both LBBB and right bundle branch block (RBBB) are frequent on the first ECG after cardiac arrest but seems to be transient 85,86 . In a Danish study it was observed that >90% of the LBBB´s and RBBB´s had resolved after four hours 86 .…”

Prognostic value of transient conduction disturbance in out‐of‐hospital cardiac arrest

“…We speculate that CLBBB should occur at the presence of a localized injury of the left bundle branch, such as myocardial infarction. 13,16 Therefore, the presence of CLBBB might indicate a limited injury of the myocardium rather than the severity of hypoperfusion associated with the cardiac arrest itself.…”

“…Although the presence of bundle branch block had been reported to be associated with high mortality following OHCA, these investigations had been undertaken in selected populations, such as the subgroup of the hypothermia trial. [9][10][11][12][13] Furthermore, the majority of cases of bundle branch block following OHCA resolve during the acute phase, 9,10 but the prognostic value of these transient electrocardiographic changes have not been explored well.…”