Myocardial Infarction

Previously at SMACC, Steve talked about NonSTEMI that needed the cath lab immediately and showed many ECGs which represented acute coronary occlusion (Myocardial Infarctions) but present on the ECG as very subtle findings (http://hqmeded-ecg.blogspot.com/search?q=subtle), particularly as subtle ST segment elevation that does not meet “STEMI” criteria and is diagnosed as NonSTEMI.

Now, he builds on that idea and challenges the whole idea of a dichotomy between STEMI and NonSTEMI. These are NOT distinct pathologies, but rather exist on a continuum of intracoronary thrombus. Nevertheless, this false dichotomy is rarely recognised by emergency physicians or cardiologists, and patients suffer because of it. There are obvious STEMI, which always need the cath lab emergently, and for which time is myocardium.

On the other hand, there are patients whose symptoms are resolved, ECG is non-diagnostic, shows no active ischemia nor subtle ST elevation, but whose troponin is positive and their resolved chest pain is due to an MI with an open artery and no ongoing myocardial cell death. These are NonSTEMI that can be treated with antiplatelet and antithrombotic therapy and get their angiogram the next day. And then there are the patients who have subtle ST elevation representing acute coronary occlusion, or who have active symptoms and/or persistent ECG ischemia. These patients do NOT have STEMI but do need the cath lab now. 25% of occlusions do NOT have diagnostic ST elevation and they do not get their angiogram until 24-36 hours later; their outcomes are worse: they have worse LV function, higher biomarkers, and higher mortality than NonSTEMI whose arteries are open at next-day cath.

Steve advocates for an end to another dichotomy: activate the cath lab (Pathway A) or do NOT activate. Instead, he advocates what they, at Hennepin County Medical Center, call “Pathway B”: emergent consultation with cardiology, including a high quality emergency contrast echocardiogram to look for wall motion abnormality. Finally, he shows a variety of ECGs which represent subtle coronary occlusion or ongoing ischemia.

For more head to: codachange.org/podcasts