Clinical Research
Acute Myocardial Infarction
The Pre-Hospital Electrocardiogram and Time to Reperfusion in Patients With Acute Myocardial Infarction, 2000–2002: Findings From the National Registry of Myocardial Infarction-4

https://doi.org/10.1016/j.jacc.2005.10.077Get rights and content
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Objectives

The aim of this study was to determine the use of pre-hospital electrocardiogram (ECG) in patients with ST-segment elevation myocardial infarction (STEMI) undergoing reperfusion therapy, and evaluate the effect of pre-hospital ECG on door-to-reperfusion times.

Background

Although national guidelines recommend the use of pre-hospital ECG, there is limited contemporary information about its current use and effectiveness.

Methods

Using data from the National Registry of Myocardial Infarction-4, we studied patients with STEMI or left bundle branch block who received acute reperfusion with either fibrinolytic therapy (n = 35,370) or primary percutaneous coronary intervention (PCI) (n = 21,277) within 6 h of admission. We determined the prevalence of pre-hospital ECG use, evaluated the association between pre-hospital ECG and door-to-reperfusion time, and estimated the incremental reduction in time to reperfusion using hierarchical models to adjust for differences in patient and hospital characteristics.

Results

A pre-hospital ECG was performed in 4.5% of the fibrinolytic therapy cohort and in 8.0% of the PCI cohort. After adjusting for patient and hospital characteristics, the use of pre-hospital ECG was associated with a significantly shorter geometric mean door-to-drug time: 24.6 min (95% confidence interval [CI]: 23.7 to 25.5) vs. 34.7 min (95% CI: 34.2 to 35.3; p < 0.0001), and a significantly shorter geometric mean door-to-balloon time (94.0 min [95% CI: 91.8 to 96.3] vs. 110.3 min [95% CI: 108.7 to 112.0]; p < 0.0001).

Conclusions

The national use of pre-hospital ECG to diagnose and facilitate the treatment of STEMI remains low. When used, however, pre-hospital ECG is associated with a significantly shorter time to reperfusion.

Abbreviations and Acronyms

AMI
acute myocardial infarction
ECG
electrocardiogram
EMS
Emergency Medical Services
LBBB
left bundle-branch block
NRMI
National Registry of Myocardial Infarction
PCI
percutaneous coronary intervention
STEMI
ST-segment elevation myocardial infarction

Cited by (0)

This research was supported by the National Heart, Lung, and Blood Institute, grant R01 HL72575-04. Dr. Blaney is employed by Genentech, Inc., South San Francisco, California. Genentech approved the study and provided access to the NRMI database at no charge; however, Genentech did not provide any direct support for the study. The first two authors contributed equally to this work. Dr. Blaney is employed by Genentech, Inc., South San Francisco, California.