Importance and limits of pre-hospital electrocardiogram in patients with ST elevation myocardial infarction undergoing percutaneous coronary angioplasty

Background: The purpose of this study is to present data on the effects of pre-hospital electrocardiogram (PH-ECG) on the outcome of ST elevation myocardial infarction (STEMI) patients treated with percutaneous coronary angioplasty (PCI) included in a registry undertaken in the Italian region of Lombardy. Pre-hospital 12-lead electrocardiogram is recommended by current guidelines in order to achieve faster times to reperfusion in patients with STEMI. Methods: The registry includes 3901 STEMI patients who underwent primary PCI over an 18-month period. Results: Mean age was 63 +/- 12 years. Admission through the emergency medical system (EMS) occurred in 1603 patients (40%): they were older, more frequently had previous MI, TIMI flow = 0 at entry and were more frequently in Killip class > 1 than patients who were not admitted through the EMS. Among the patients admitted through the EMS, PH-ECG was obtained in 475 patients (12%). These patients had less frequently an anterior MI, but more frequently had absence of TIMI flow at entry than patients whose ECG was not teletransmitted. Moreover, they had a significantly shorter first medical contact-to-balloon time and a trend toward a lower 30-day death rate (5.3% vs 7.9 %, p=0.06). However, only patients in Killip class 2-3 had a significantly lower mortality when the diagnostic ECG was transmitted, whereas no difference was found in Killip class 1 or Killip class 4 patients. Conclusions: In this registry, PH-ECG significantly decreased first medical contact-to-balloon time. Attempts to achieve faster reperfusion times should be undertaken, as this may result in improved outcome, particularly in patients with mild to moderate symptoms of heart failure.