Use of emergency medical services in acute myocardial infarction and subsequent quality of care: observations from the National Registry of Myocardial Infarction 2.
BACKGROUND
National practice guidelines strongly recommend activation of the 9-1-1 Emergency Medical Systems (EMS) by patients with symptoms consistent with an acute myocardial infarction (MI). We examined use of the EMS in the United States and ascertained the factors that may influence its use by patients with acute MI.


RESULTS
From June 1994 to March 1998, the National Registry of Myocardial Infarction 2 enrolled 772 586 patients hospitalized with MI. We excluded those who transferred in, arrived at the hospital >6 hours from symptom onset, or who were in cardiogenic shock. We compared baseline characteristics and initial management for patients who arrived by ambulance versus self-transport. EMS was used in 53.4% of patients with MI, a proportion that did not vary significantly over the 4-year study period. Nonusers of the EMS were on average younger, male, and at relatively lower risk on presentation. In addition, payer status was significantly associated with EMS use. Use of EMS was independently associated with slightly wider use of acute reperfusion therapies and faster time intervals from door to fibrinolytic therapy (12.1 minutes faster, P<0.001) or to urgent PTCA (31.2 minutes faster, P<0.001).


CONCLUSIONS
Only half of patients with MI were transported to the hospital by ambulance, and these patients had greater and significantly faster receipt of initial reperfusion therapies. Wider use of EMS by patients with suspected MI may offer considerable opportunity for improvement in public health.
Canto
John G
JG
Chest Pain Center and Division of Cardiovascular Diseases, University of Alabama at Birmingham, 35294-0012, USA.
Zalenski
Robert J
RJ
Ornato
Joseph P
JP
Rogers
William J
WJ
Kiefe
Catarina I
CI
Magid
David
D
Shlipak
Michael G
MG
Frederick
Paul D
PD
Lambrew
Costas G
CG
Littrell
Katherine A
KA
Barron
Hal V
HV
D000368:Aged; D000552:Ambulances / Q000706:statistics & numerical data; D003430:Cross-Sectional Studies; D003710:Demography; D004632:Emergency Medical Services / Q000592:standards* / Q000706:statistics & numerical data*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000628:therapy*; D015425:Myocardial Reperfusion / Q000706:statistics & numerical data*; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D011787:Quality of Health Care / Q000706:statistics & numerical data*; D012042:Registries / Q000706:statistics & numerical data; D013997:Time Factors; D014187:Transportation of Patients / Q000706:statistics & numerical data*; D014481:United States