Field ECGs Improve Time-to-Treatment Balloon Time

A new study has found that heart attack victims who undergo electrocardiograms (ECGs) in the field experience significantly reduced time-to-treatment or door-to-balloon (D2B) time.

Researchers at Providence Hospital and Medical Center (Southfield, MI, ISA) conducted a prospective, observational study of D2B time in three hospitals in Southeast Michigan (USA) from October 1, 2003 through April 30, 2008. At each center, a protocol was initiated where emergency medical services (EMS) personnel obtained a 12-lead ECG during initial assessment in the field from patients with symptoms suggestive of ST segment elevation myocardial infarction (STEMI). The prehospital ECG data was transmitted via cellular link to an emergency room (ER) computer receiving station where physicians interpreted the information and upon diagnosis of STEMI, and activated the cardiac catheterization laboratory (CCL) team prior to the patient's arrival. Similar data were collected for all patients who came to the ER without prehospital ECGs (the control group). Baseline characteristics including cardiac risk factors were similar between the groups.

The results showed that 241 patients with STEMI received in-hospital ECGs and 108 patients received prehospital ECGs. In-hospital mortality was 2% for the control group (7 out 241) compared with no deaths in those patients with prehospital ECG. Patients in the in-hospital ECG group who presented during working hours waited 75 minutes prior to reperfusion treatment, while those presenting during off-hours (weekends and holidays) experienced a 98-minute wait time. In the prehospital ECG group there was a significant reduction in D2B time independent of presentation time, with 98% of patients in this group who were admitted during off-hours having treatment within 90 minutes. The study was published in the January 2010 issue of Catheterization and Cardiovascular Interventions.

"Our results reemphasize the importance of early activation of the CCL in order to improve time-to-reperfusion in patients with STEMI,” said lead author cardiologist Shukri David, M.D., section chief of cardiology at Providence Hospital.

STEMI occurs when a blood clot totally obstructs a coronary artery, and is treated with reperfusion therapy to reestablish blood flow as quickly as possible. Prior studies have shown that rapid D2B with angioplasty was associated with lower mortality rates and that for each 30 minutes of delay, the relative risk of 1-year mortality increases by 7.5%. In an effort to improve patient survival rates, the American College of Cardiology (ACC, Washington, DC, USA) and the American Heart Association (AHA, Dallas, TX, USA) developed U.S. national guidelines that state hospitals treating STEMI patients should strive to achieve a median D2B time of less than 90 minutes.

Related Links:
Providence Hospital and Medical Center
American College of Cardiology
American Heart Association