Abstract 1768: Effect of Pre-Hospital 12-Lead ST-Segment Monitoring on Time to Treatment in Acute Coronary Syndrome: The ST SMART Study
The ST SMART Study (Synthesized Twelve-lead ST Monitoring & Real-time Tele-electrocardiography) is a randomized clinical trial ending in 2008 to determine whether individuals who call 911 with acute coronary syndromes (ACS) will have more timely hospital treatment & better outcomes if emergency department (ED) clinicians receive ischemia monitoring ECGs from the field.
Study Aim: Determine effect of the pre-hospital ECG intervention on:
scene time (vs. pre-study),
time from 911call to 1st ECG, &
door to balloon time in ST elevation myocardial infarction (STEMI).
Methods: All 29 emergency vehicles in Santa Cruz County, CA are equipped with portable monitor-defibrillators with special study software that:
synthesizes a 12-lead ECG from 5 electrodes,
measures ST amplitudes every 30 secs, &
automatically transmits an ECG to the target ED if there is a change in ST amplitude of 200 μV in ≥1 lead or 100 μV in ≥2 contiguous leads.
If ECG transmission fails, automatic redialing occurs for a total of 3 attempts. Experimental group patients have their pre-hospital ECGs printed out in the target ED with an audible voice alarm. Control group patients have their first ECG after hospital arrival.
Results: 501 patients (mean age, 70 yrs, 53% male) have been enrolled. A total of 200 had ACS (STEMI, 28; non-STEMI, 46; unstable angina, 126). Mean pre-study vs post-study scene times were 14.7 vs 15.8 mins (p = 0.03). Time from 911 call to 1st ECG was 18 mins (± 8) in the experimental group vs 61 mins (± 48) in the control group (p < .001). Door to balloon time in the 25 STEMI patients who had percutaneous coronary intervention averaged 83 mins (± 25) in experimental vs 160 mins (± 138) in control patients (p = .062).
Conclusions: Pre-hospital 12-lead ST segment monitoring results in a minimal increase in scene time (1 min) and a maximal decrease in time to first ECG (43 mins). Whether the observed reduction in door to balloon time is sufficient to provide a clinical benefit will be the focus of the ongoing ST SMART trial.