A STEMI (ST-Segment Elevation Myocardial Infarction) is a specific type of myocardial infarction (MI) which demonstrates characteristic ECG changes including marked elevation in the ST segment in the cardiac cycle. Each year, one person in 2,300 in Toronto will suffer a STEMI.

Unlike some “heart attacks”, STEMIs are treatable by new techniques that rapidly restore perfusion to the heart muscle by removing blockages in the coronary arteries. Clot-busting drugs and mechanical re-expansion of the blocked artery are both available as reperfusion therapies at specialized cardiac centres in Toronto. Rapid restoration of blood flow dramatically reduces deaths and improves long term outcomes.

Urgent access to reperfusion therapy, particularly PCI, has been proven to dramatically improve survival from STEMI. Toronto EMS treats about 7,000 chest pain patients per year with nitroglycerine and/or ASA and between 5 and 10% of those are likely to be having a STEMI. Once we are fully involved both in taking patients directly to the 24-hour PCI lab and in bringing STEMI patients from Toronto hospitals to the PCI labs, Toronto EMS paramedics will be involved in the care of the majority of the estimated 1,000 -1,200 annual STEMI patients.

No. It is a change in practice. Timely 12-lead acquisition is the standard of Level III Paramedic care for patients with symptoms of myocardial ischemia.

Although Advanced Care Paramedics already receive 12- lead acquisition instruction in their Level III training, 24-hour PCI has not been available in Toronto and no system for direct EMS access to PCI has been in place. Now, with a 24-hour PCI lab at St. Michael’s Hospital, we are finally able to provide this service, and we are working with Toronto General and Sunnybrook to implement similar processes in the near future.

This is a very complex system with many components which must be in place both in hospitals and in the EMS system. We are starting with a limited roll-out so we can adjust procedures as required and to ensure that the system is working smoothly before going city-wide.

To facilitate the transition to this changed system, only Level III Paramedic crews will be utilized as they have already received formal 12-lead acquisition training. Furthermore, many STEMI patients will require medications that only a Level III Paramedic can administer in the field. Instead of short trips to local EDs, STEMI patients will now have to be managed for longer as they will be diverted to PCI centres some distance away. In other centres where Level I Paramedics are performing 12-lead acquisition, ALS is either not available at all or the local cardiac program does not involve the same extensive ALS pre-hospital STEMI interventions.

Level I crews should treat their chest pain patients as per standard medical directives taking the patient to the closest appropriate ED with advanced notification as necessary.