Systematic review and meta-analysis of the benefits of out-of-hospital 12-lead ECG and advance notification in ST-segment elevation myocardial infarction patients

Study objective: To present a review of out-of-hospital identification of ST-segment elevation myocardial infarction patients transported by emergency medical services with 12-lead ECG and advance notification versus standard or no cardiac monitoring.

Methods: EMBASE, PubMed, and the Cochrane Library were searched, using controlled vocabulary and keywords. Randomized controlled trials and observational studies were included. Outcomes included short-term mortality (≤30 days), door-to-balloon/needle time and/or first medical contact-to-balloon/needle time. Pooled estimates were determined, where appropriate. Results were stratified by percutaneous coronary intervention or fibrinolysis.

Results: The search yielded 1,857 citations, of which 68 full-texts were reviewed and 16 studies met the final criteria: 15 included data on percutaneous coronary intervention and 3 on fibrinolysis (2 included both). Where percutaneous coronary intervention was performed, out-of-hospital 12-lead ECG and advance notification was associated with a 39% reduction in short-term mortality (8 studies; n=6,339; risk ratio 0.61; 95% confidence interval 0.42 to 0.89; P=.01; I(2)=30%) compared with standard or no cardiac monitoring. Where fibrinolysis was performed, out-of-hospital 12-lead ECG and advance notification was associated with a 29% reduction in short-term mortality (1 study; n=17,026; risk ratio 0.71; 95% confidence interval 0.54 to 0.93; P=.01). First medical contact-to-balloon, door-to-balloon, and door-to-needle times were consistently reduced, though large heterogeneity generally precluded pooling.

Conclusion: The present study adds to previous reviews by identifying and appraising the strength and quality of a larger body of evidence. Out-of-hospital identification with 12-lead ECG and aadvance notification was found to be associated with reductions in short-term mortality and first medical contact-to-balloon, door-to-balloon, and door-to-needle time.