Upsloping ST depression: Is it acute ischemia?

Area of Science:

• Cardiology
• Interventional Cardiology
• Diagnostic Electrocardiography

Background:

• Acute coronary syndrome (ACS) requires accurate diagnosis for timely intervention.
• Electrocardiogram (ECG) findings are crucial in differentiating myocardial infarction (MI) types.
• Left circumflex artery (LCx) dissection is a rare but serious cause of ACS.

Observation:

• A patient presented with ACS, showing specific ECG changes: upsloping ST depression in leads I, II, V3-V6 and ST elevation in lead aVR.
• Coronary angiography identified a spontaneous dissection in a large, dominant LCx artery as the sole coronary lesion.
• During percutaneous coronary intervention (PCI) of the LCx dissection, distal occlusion occurred, supplying the posterior descending artery.

Findings:

• The distal LCx occlusion resulted in ST elevation myocardial infarction (STEMI).
• The ECG pattern of STEMI showed ST elevation in leads III and aVF, but notably not in lead II.
• This specific ECG manifestation was interpreted as indicative of a right coronary artery (RCA) territory MI, despite the primary event being in the LCx artery.

Implications:

• This case highlights the importance of recognizing atypical ECG presentations in complex coronary artery pathologies.
• It underscores the potential for misattribution of MI location based solely on standard ECG criteria when non-coronary artery disease (non-CAD) events or complex anatomical variations are involved.
• Understanding these nuances is critical for guiding appropriate therapeutic strategies and improving patient outcomes in interventional cardiology.