Cell phone technology transmits pre-hospital ECG, improves time-to-treatment
Paramedics equipped with pre-hospital ECG devices that wirelessly transmit critical information to emergency rooms while in route to the hospital can reduce the time it takes to diagnose and treat patients by more than 30 percent, according to a study presented at the annual Heart Rhythm Society (HRS) meeting held in San Francisco last week.

The researchers from the University of California, San Francisco (UCSF), said the study is the first to prospectively evaluate hospital time-to-treatment and outcomes in individuals, who were randomized to receive a pre-hospital ECG versus the usual method of obtaining an ECG after hospital arrival.

Beginning in 2003, all 29 paramedic vehicles in Santa Cruz County, Calif., were equipped with special ECG devices, marking the launch of the Synthesized Twelve-lead ST Monitoring & Real-time Tele-electrocardiography (ST SMART) study. These modified machines wirelessly transmit an ECG reading to the hospital through mobile phone technology, with an audible voice alarm stating an incoming ECG from the field. They also continuously monitor the patient’s status and re-transmit information to the hospital if changes are detected.

The ST SMART study measured two critical windows of time that directly link to survival and long-term well-being of an acute MI patient. Results showed that pre-hospital ECG transmissions shortened the time to diagnosis, the time it took to receive the first ECG after the patient dialed 911 and the door-to-balloon time.

“By utilizing mobile phone/ECG technology, physicians are able to diagnose patients faster and mobilize resources in anticipation of a patient’s arrival, rather than reacting once the patient is already in the door,” said lead author Barbara Drew, PhD, from UCSF.
More than 730 patients have been enrolled in the ST SMART study (acute MI, 92; unstable angina, 91). Mean scene time increased from 15 minutes pre-implementation to 17 minutes post-implementation. The difference was significant.

The mean time from the 911 call to the first ECG was 75 minutes less in patients with versus without pre-hospital ECG (19 vs. 94 minutes, respectively). The difference was significant. The mean door-to-balloon time in STEMI patients was 36 minutes less in patients with versus without pre-hospital ECG (79 vs. 116 minutes, respectively).

A greater proportion of patients who received a pre-hospital ECG received PCI within 90 minutes versus those without a pre-hospital ECG (65 vs. 36 percent).

Drew concluded that pre-hospital ECG results in a small but statistically significant increase in scene time of two minutes. “However, this is negated by a much greater time savings of greater than 36 minutes in door-to-balloon time.”