EMT Test Speeds Heart Attack Care

Electrocardiograms read by EMTs could improve severe heart attack treatment

(RxWiki News) Time is critical when a patient suffers a severe heart attack, prompting researchers to hunt for methods to speed up care. Training emergency medical technicians to administer electrocardiograms (ECGs) may improve patient survival.

ECGs help paramedics evaluate chest pain and ensure patients receive faster treatment if they have suffered ST-segment elevation myocardial infarction (STEMI), a severe type of heart attack that involves complete blockage of a coronary artery.

"Call 9-1-1 immediately for heart attack symptoms."

Robin A. Ducas, MD, lead investigator from the University of Manitoba in Canada, noted that patient deaths following a heart attack are related to delays in restoring blood flow to the heart. He said that a delay of even 30 minutes has been linked to increased mortality.

Previous research indicated only 14 percent of patients receive life-saving clot-busting drugs within 30 minutes of initial medical contact, the recommended benchmark. Only 11 percent receive angioplasty within the recommended 90-minute time frame.

Dr. Ducas said that training EMTs to administer and interpret ECGs with oversight from an on-call doctor would help reduce the delays and improve treatment time.

During the study, researchers implemented a system to train EMTs to administer and interpret ECGs for signs of STEMI. If STEMI was suspected, medics transmitted the ECG results to a hand-held device monitored by an on-call physician. If STEMI was confirmed, EMTs were directed to begin clot-busting drugs or to alert the hospital to prepare the catheterization laboratory for emergency angioplasty to open the blocked artery.

Patients were then transported directly to the hospital's cardiology department or catheterization lab. Patients were taken to the nearest hospital emergency room if the ECG did not confirm STEMI.

Investigators evaluated 380 patient cases between July 2008 and July 2010 after the training was completed, of which 41 percent of patients were directed to an angioplasty-capable hospital. Of 226 STEMI patients, 70 percent received angioplasty and 21 percent received clot-busting drugs.

Among the group that received clot busters, the average time from first medical contact to treatment was 32 minutes. On average angioplasty patients received treatment within 76 minutes. There were seven missed STEMI cases using the ECG method, and an additional seven cases in which the catheterization lab was falsely activated.

In a related study of 703 audited cases of chest pain, of which 323 were negative for STEMI, slightly over half of patients were discharged from the hospital after a diagnosis of "nonspecific chest pain," while two patients developed STEMI at the hospital and one STEMI case was missed.

"The high level of false positives is a concern, given the risk of treatment," said Dr. Ducas. "We do not have a clear guide as to what are acceptable levels of false positives and negatives. However, we have found both in the literature and in our own study that EMS pre-hospital ECG interpretation is fast, reliable, and plays a pivotal role in the care for patients with STEMI."

In an editorial accompanying the articles, Robert C. Welsh, MD, FRCPC, from the University of Alberta and the Mazankowski Alberta Heart Institute in Canada, said the program is optimal to advance STEMI care.

"Although this approach is dependent on a motivated group of physicians willing to invest additional time and energy to deliver enhanced STEMI care, it allows pre-hospital confirmation of diagnosis, individual patient risk stratification, immediate decision regarding the optimal mode of reperfusion, and expansion of optimal systems of care to rural patients," Dr. Welsh said.

The pair of studies were recently published in the Canadian Journal of Cardiology.

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Review Date: 
July 20, 2012