emergency medicine iceland

Dec 7, 2013

Chest pain with subtle yet serious ECG changes

Following is a classic case underlining the importance of "STEMI equivalents" or ECG patterns requiring prompt attendance and cath lab activation as if it were a true STEMI.
A 74 year-old previously healthy woman presented to the emergency department by ambulance with chest tightness and left arm numbness following exercise. She was stable on arrival, BP was 140/65 and pulse regular 65/min and pain free after receiving nitroglycerin.
Describe the T waves shown on the ECG
This ECG mainly shows prominent inverted T waves in V2-5.
What are they indicative of?
Biphasic or inverted T waves in precordial leads strongly suggest critical left anterior descending coronary artery stenosis. This pattern is referred to as Wellens syndrome or "LAD coronary T-wave syndrome". Generally, there is a history of angina and troponin levels are either normal or mildly elevated. ST elevations are rarely present. The majority of patients with this ECG pattern will develop extensive anterior myocardial infarction within weeks if no intervention is taken. Therefore, recognizing this pattern is of critical importance and cardiac catheterization should be performed promptly, despite a pain free patient.
Which test could be lethal for this patient?
This patient is likely to have very limited circulation to the anterior myocardium. A stress test could easily induce arrhythmias or in worst case cardiac arrest.
What are STEMI equivalents?
Patients with STEMI equivalents have acute coronary artery occlusion without the classic ST elevation patterns we have all been taught not to miss.
A paper by Rokos et al published in the American Heart Journal in 2010* reviewed STEMI equivalents requiring cath lab activation:
1) Posterior (V1-3) ST depressions
2) ST elevation >1mm in aVR along with depression of anterior leads
3) de Winter ST/T wave complexes anteriorly

This article is free to view in link below but our great colleague and emergency physician Andy Neill in Ireland has reviewed the article nicely on his blog.

Wellens syndrome is a chronic coronary artery occlusion and therefore not a STEMI equivalent. It is nonetheless a serious and unstable condition that requires prompt intervention and every physician should be able to recognize it.

Our patient was admitted to the cardilogy ward and was scheduled for cardiac catheterization the following day. She was stable and pain free on admission. A few hours later she developed a circulatory collapse and underwent acute catheterization which revealed critical stenosis of the left main coronary artery, LAD, circumflex artery and right coronary artery.

* IC Rokos, WJ French, A Mattu, G Nichol, ME Farkouh, J Reiffel, GW Stone. Appropriate Cardiac Cath Lab activation: Optimizing electrocardiogram interpretation and clinical decision-making for acute ST-elevation myocardial infarction. Am Heart J, 160 (2010), pp. 995–1003.

Read more about Wellens at LITFL What is Wellens syndrome?

Maria Reynisdottir (stud. med.)

No comments:

Post a Comment