Emergency medical services management of ST-segment elevation myocardial infarction in the United States--a report from the American Heart Association Mission: Lifeline Program

Objective: ST-segment elevation myocardial infarction (STEMI) is a major cause of morbidity and mortality in the United States. Emergency medical services (EMS) agencies play a critical role in its initial identification and treatment. We conducted this study to assess EMS management of STEMI care in the United States.

Methods: A structured questionnaire was administered to leaders of EMS agencies to define the elements of STEMI care related to 4 core measures: (1) electrocardiogram (ECG) capability at the scene, (2) destination protocols, (3) catheterization laboratory activation before hospital arrival, and (4) 12-lead ECG quality review. Geographic areas were grouped into large metropolitan, small metropolitan, micropolitan, and noncore (or rural) by using Urban Influence Codes, with a stratified analysis.

Results: Data were included based on responses from 5296 EMS agencies (36% of those in the United States) serving 91% of the US population, with at least 1 valid response from each of the 50 states and the District of Columbia. Approximately 63% of agencies obtained ECGs at the scene using providers trained in ECG acquisition and interpretation. A total of 46% of EMS systems used protocols to determine hospital destination, cardiac catheterization laboratory activation, and communications with the receiving hospital. More than 75% of EMS systems used their own agency funds to purchase equipment, train personnel, and provide administrative oversight. A total of 49% of agencies have quality review programs in place. In general, EMS systems covering higher population densities had easier access to resources needed to maintain STEMI systems of care. Emergency medical services systems that have adopted all 4 core elements cover 14% of the US population.

Conclusions: There are large differences in EMS systems of STEMI care in the United States. Most EMS agencies have implemented at least 1 of the 4 core elements of STEMI care, with many having implemented multiple elements.