Shark-Fin Pattern in aVR Lead as First Manifestation of Acute Left Main Coronary Artery Occlusion

"Shark-fin" is a rare but serious electrocardiogram (ECG) pattern often suggestive of proximal left anterior descending or left main coronary artery (LMCA) involvement.

A 66-year-old man came to our hospital for acute chest pain and cardiogenic shock. ECG showed a shark-fin waveform in aVR lead along with diffuse ST-segment depression. Urgent coronary angiography demonstrated complete thrombotic LMCA occlusion and primary percutaneous coronary intervention with stent implantation allowed for hemodynamic stabilization and ECG normalization.

Shark-fin is one of a series of patterns described as "ST-segment elevation myocardial infarction equivalent." It usually affects the anterior leads, expressing a left anterior descending artery critical lesion or occlusion. Here, the presence of this sign in the aVR lead was associated with LMCA acute, total, occlusion and a rapid diagnosis was crucial to enable the most appropriate treatment.

Shark-fin sign is an "ST-segment elevation myocardial infarction equivalent" pattern. When involving the aVR lead, it should raise immediate suspicion for LMCA occlusion. Rapid recognition and emergent reperfusion can be lifesaving.