ACC: No pre-hospital ECG = 62% longer D2B times
NEW ORLEANS--For those with a suspected ST-elevation MI (STEMI), calling an ambulance as opposed to arriving at the hospital by other means, can fast-track access to care. Also, patients who have an electrocardiogram (ECG) in the ambulance en-route to the hospital receive first-line care in half the time, yet nearly half of patients elect not to take an ambulance and among those who do, many do not get an ECG, according to data from the ACTIVATE-SF registry presented April 2 at the American College of Cardiology (ACC) scientific sessions.

“Getting an ECG by first responders greatly improves the speed of effective care at the hospital,” said the study’s principal investigator James M. McCabe, MD, University of California, San Francisco.

The ACTIVATE-SF registry examined all possible STEMI referrals (360 patients) to the cath lab of an urban trauma center and tertiary care hospital in San Francisco through central paging systems.

Even after adjusting for demographic factors, traditional cardiovascular risk factors, severity of illness and extent of ECG changes (e.g., how “positive” the diagnostic ECG test was), merely not presenting to the emergency room (ER) by ambulance and therefore not getting a pre-hospital ECG lengthens the total time in the ER before getting referred to the cath lab by 62 percent, McCabe said.

While the PCI procedural time did not vary based on how the patient arrived at the hospital, the improved efficiency of managing patients in the ER largely due to getting a pre-hospital ECG reduced door-to-balloon time (D2B) by more than a quarter.

A patient’s likelihood of dying “more than doubles (3 to 7.5 percent) if D2B times increase from 90 to 150 minutes, according to McCabe, adding that previous studies have shown that for every 30-minute delay, the chances a patient will die within one year of the heart attack increases by 7.5 percent.

“What’s really striking is that patients who took an ambulance were generally sicker than those who did not, and despite the fact that these patients needed more intensive care upon arriving at the hospital, they were still able to get through the emergency department to the catheterization lab more than twice as fast as people who didn’t take an ambulance and didn’t get a pre-hospital ECG.”

McCabe and colleagues found that Asian race was associated with delays in the ER for those requiring a translator but not with significant differences in total time to reperfusion. However, no delays were seen for other racial groups.

The researchers concluded that pre-hospital ECGs are associated with significant decreases in time spent in the ER despite more critical illness among ambulance users requiring initial stabilization.

“Despite these quality controls, and in some cases redundancies in our processing of patients, we are still seeing marked improvements in door-to-balloon times,” McCabe said. “It reinforces the importance of dialing 9-1-1 when a heart attack is suspected.”

As a next step, San Francisco will be implementing city-wide remote transmission of ECGs, and McCabe and his team plan to study the effect to determine whether this technology might result in even more efficient transfer of STEMI patients to the cath lab.