A woman in her late 60s presented to the emergency department after an episode of syncope. She described several other episodes occurring at rest over the past several weeks. She denied palpitations, chest pain, and shortness of breath. She was otherwise in excellent health and not taking any medications. She had no family history of syncope or sudden death. Her vital signs and physical examination were unremarkable. The initial electrocardiogram (ECG) results were normal, but premature ventricular contractions (PVCs) were noted on telemetry. Shortly thereafter, 2 episodes of fast polymorphic ventricular tachycardia (PVT), 30 minutes apart, were recorded, both lasting less than 4 seconds (Figure 1A). A repeat ECG showed PVCs (Figure 1B). Laboratory test results including serum potassium and magnesium as well as 3 serial troponin levels were normal. Echocardiography showed normal left ventricular systolic function without wall motion abnormalities or valvular abnormalities. Coronary angiography showed a 50% stenosis of the left circumflex artery. Instant wave-free ratio across the stenosis was 1.0.