Novel electrocardiogram configurations and transmission procedures in the prehospital setting: effect on ischemia and arrhythmia determination.
OBJECTIVE
The aims of this report are to (1) describe a novel prehospital 12-lead electrocardiogram (ECG) configuration and transmission procedure used in the Synthesized Twelve-lead ST Monitoring and Real-time Tele-electrocardiography Study and to (2) report on the frequency of arrhythmias in field ECGs compared with the first hospital ECG.


METHODS
The Synthesized Twelve-lead ST Monitoring and Real-time Tele-electrocardiography Study is a 5-year randomized clinical trial ending in 2008. All emergency vehicles responding to 911 calls in Santa Cruz County, Calif, have been equipped with portable monitor defibrillators with a special study software that (1) synthesizes a 12-lead ECG from 5 electrodes, (2) measures ST amplitudes in all 12 leads every 30 seconds, and (3) automatically transmits an ECG to the target emergency department if there is a change in ST amplitude of 200 microV in 1 lead or more or 100 microV in 2 contiguous leads or more lasting 2.5 minutes. An initial ECG is transmitted by paramedics, which activates the software. Subsequent transmissions of ST event ECGs occur automatically without paramedic decision making.


RESULTS
Prehospital ECGs had a greater frequency of arrhythmias than the first hospital ECG in the group as a whole (n = 433; 33.3% vs 28.9%; P < or = .001), as well as the subgroup with acute coronary syndrome (n = 185; 30.3% vs 26.5%; P < or = .001). More tachyarrhythmias occurred in the field and slightly more bradyarrhythmias occurred at the time of the first hospital ECG.


CONCLUSIONS
Prehospital continuous 12-lead ST-segment ischemia monitoring with computer-assisted automatic mobile telephone transmission of ST event ECGs to the target hospital is feasible. More arrhythmias occur in the prehospital phase than are evident on the first hospital ECG.
Drew
Barbara J
BJ
Department of Physiological Nursing, N631H, University of California, San Francisco, CA 94143-0610, USA. barbara.drew@nursing.ucsf.edu
Sommargren
Claire E
CE
Schindler
Daniel M
DM
Zegre
Jessica
J
Benedict
Kent
K
Krucoff
Mitchell W
MW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000453:epidemiology*; D004562:Electrocardiography / Q000379:methods / Q000706:statistics & numerical data*; D004632:Emergency Medical Services / Q000379:methods / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007511:Ischemia / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity; D017216:Telemedicine / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology