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 suggest that the incidence of STEMIs in Ontario is about 7,000 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 (such as fibrinolysis therapy)

Effective reperfusion requires timely diagnosis, transportation and treatment when STEMI is diagnosed or suspected, and the timeliness of the intervention is measured in minutes. Canadian Cardiovascular Society and American College of Cardiology/American Heart Association 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.

Drivers of the STEMI System of Care in Ontario

The STEMI Network Working Group, comprised of cardiologists, interventional cardiologists, emergency department physicians, base hospital medical directors, paramedic chiefs, paramedics and administrators works to standardize the STEMI care across Ontario.

• Recommendations for Best-Practice STEMI management in Ontario
• Best Practice Recommendations for Remote Communities

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.

Ontario Emergency Department Protocol

The Ontario Emergency Department Protocol 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:

• Emergency Department STEMI Algorithm
• Emergency Department Pocket Cards
• STEMI Education

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: Less than 60-minute drive time to a PCI hospital from a Non-PCI hospital ED with a target D2B of less than 120 minutes.
• Pharmacoinvasive: Greater than 60-minute drive time to a PCI hospital from a Non-PCI hospital ED. Pharmacoinvasive is a reperfusion strategy which requires two steps to achieve the target a D2N time of less than 30 minutes and emergent transfer to a PCI centre in less than 24 hours for a coronary angiography.

Ontario Paramedic 12-Lead ECG Guidelines

The Ontario Paramedic 12-Lead ECG Guidelines were developed by the STEMI Working Group to support standard learning objectives related to 12-Lead (ECG) acquisition, interpretation and pre-hospital STEMI management for the basic paramedic college curriculum. Use this document as a guideline as you plan your program curriculum.

Sharing Best Practices

• Sharing Best Practices – Timely Access to Reperfusion Therapy for STEMI in Ontario
• Program Quality Improvement Initiatives to Address STEMI Indicators