ST Elevation Myocardial Infarction (STEMI)


ST-segment elevation myocardial infarction (STEMI) is a form of heart attack that can cause death if not treated quickly. Approximately one-third of acute coronary syndromes are classified as STEMI (Fitchett, 2011). Data from the Canadian Institute for Health Information (CIHI) Discharge Abstract Database (DAD) suggest that the incidence of STEMI in Ontario is approximately 68 of every 100,000 adult residents, a total of about 7,000 STEMIs per year.

STEMIs are treated through the restoration of blood flow in the coronary artery through one of two treatment options or “reperfusion” modalities:

  • Percutaneous coronary intervention (PCI), a procedure in which the coronary arteries are mechanically reopened using a balloon or aspiration catheter and the placement of a stent in the blocked arteries.
  • Clot-busting drugs (i.e., fibrinolysis therapy).

Timely reperfusion requires timely diagnosis, transportation and treatment when STEMI is diagnosed or suspected, and the timeliness of the intervention is measured in minutes. The Canadian Cardiovascular Society (CCS) and  American College of Cardiology/ American Heart Association (ACC/AHA) guidelines recommend that STEMI patients treated by primary PCI presenting to a PCI capable hospital have a door-to-balloon (D2B) time of less than 90 minutes and patients treated with fibrinolysis therapy have a door-to-needle (D2N) time of less than 30 minutes; patients presenting to a non-PCI capable hospital should have a D2B time of less than 120 minutes (CCS 2004,ACC/AHA 2013).

Drivers of the STEMI System of Care in Ontario

  • In 2011 CCN established the STEMI Network Working Group, comprised of cardiologists, interventional cardiologists, emergency department physicians, base hospital medical directors, paramedic chiefs, paramedics, and administrators to address variation by standardizing STEMI care across the province of Ontario.
  • June 2013, Recommendations for Best-Practice STEMI management in Ontario were developed:
    • focused on the development of regional networks, and the development of timely protocols
  • September 2013, Management for Acute Coronary Syndromes: Best Practice Recommendations for Remote Communities
  • December 2013, the Auditor General also identified a number of opportunities: Land Ambulance Services
    • The opportunity to reinforce integrated protocols to ensure timely access to best practice care for all STEMI patients to receive optimal reperfusion therapy regardless of where they present.
  • 2016 CCN  launched STEMI Implementation Plan

STEMI System of Care Update February 2017

The Ontario STEMI Bypass Protocol

This STEMI bypass protocol enables paramedics to bypass local hospitals and transport patients with STEMI directly to a PCI capable centre.

The Ontario Emergency Department Protocol

Was developed to reinforce STEMI best practices management and reperfusion targets. To support the implementation of the protocol several clinical tools and resources have been developed and are available for use:

PCI and Non PCI Hospital Partnership Maps:

The PCI and Non PCI partnership geographical maps were designed to designate the reperfusion strategy for each Ontario hospital emergency department (ED) as either:

Primary PCI ≤ 60 minutes’ drive time to a PCI hospital from a Non PCI hospital ED with a target:

  • Door to Balloon Time (D2B) ≤ 120 minutes

Pharmacoinvasive > 60 mins drive time to a PCI hospital from a Non PCI hospital ED. The pharmacoinvasive is a reperfusion strategy which requires two steps to achieve the target:

  • Door to Needle Time (D2N) ≤  30 minutes
  • Emergent transfer to PCI center ≤24 hours for a coronary angiography

Ontario Paramedic 12-Lead ECG Guidelines

The STEMI WG’s mandate is to address variation in STEMI management and to standardize STEMI care across the province. The WG informs recommendations through best practice, published literature and expert consensus. In June 2013, the document Recommendations for Best-Practice STEMI Management in Ontario clearly defined the goals for STEMI care in Ontario including the following priority recommendation:

Priority Recommendation 6: Ensure that the appropriate infrastructure is in place in Ontario to support timely diagnosis for STEMI patients through:

  • Supporting the existing provincial paramedic education program for electrocardiogram (ECG) acquisition and STEMI identification for all paramedics.

The WG was asked by Paramedic college coordinators to help develop standardized guidelines for the 12-Lead ECG component of the paramedic college curriculum across Ontario. The guideline document has been developed for the purpose of supporting standard learning objectives related to 12-Lead (ECG) acquisition, interpretation and pre-hospital STEMI management for the basic Paramedic college curriculum.

Please feel free to utilize this document as a guideline as you plan your program curriculum.

Sharing Best Practices