Incessant Refractory Polymorphic Ventricular Tachycardia After Coronary Artery Bypass Graft

Abstract

Polymorphic ventricular tachycardia (PVT) post coronary artery bypass (CABG) surgery is associated with acute myocardial ischemia, hemodynamic instability, and metabolic derangements. When acute ischemia is suspected, a comprehensive investigation for reversible causes is justified to improve patient outcomes. We present a curious case of incessant, refractory PVT in a patient with an unknown etiology requiring percutaneous coronary intervention (PCI) post CABG. The patient was a 73-year-old female with multiple comorbidities who presented to the hospital with anginal chest pain for one day. Initial electrocardiogram (EKG) showed sinus tachycardia with ST-segment depressions in the inferior-lateral leads. Initial cardiac troponin I was elevated at 28.280 ng/mL. Dual antiplatelet therapy and heparin were started. Urgent coronary angiography revealed significant triple-vessel disease, and she subsequently underwent three-vessel CABG. Her postoperative course was complicated by PVT refractory to all antiarrhythmic therapy and ventricular fibrillatory (VF) arrest with the recovery of spontaneous circulation after defibrillation and amiodarone bolus. Despite normal electrolytes and discontinuation of all QT-prolonging agents, PVT persisted. Urgent coronary angiography revealed a patent venous graft to a previously underappreciated severely stenotic distal segment of the left anterior descending artery (LAD). She underwent PCI of the culprit lesion with the termination of PVT. Although acute graft failure is regularly the culprit for acute myocardial infarction perioperatively, emergent coronary angiography post coronary bypass surgery revealed patent grafts and a previously underestimated severe coronary lesion contributing to ongoing ischemia. Post CABG percutaneous coronary intervention (PCI) yielded a complete resolution of her arrhythmia.