Unusual trifurcation of left main coronary artery in a patient with hypertrophic obstructive cardiomyopathy: Issues in management strategy.

Background: Hypertrophic cardiomyopathy (HCM) and anomalous coronary artery arising from the opposite sinus are independently associated with increased risk of sudden cardiac death (SCD). Their coexistence in a single patient further complicates the issue by affecting management strategy and increasing the risk of sudden death.

Case report: A 21-year-old woman with hypertrophic obstructive cardiomyopathy (HOCM) having strong family history of SCD presented with exertional fatigue and palpitation. Cardiac catheterization and computed tomography (CT) coronary angiography revealed single left coronary artery where left main trunk was trifurcating into left anterior descending (LAD), left circumflex (LCX), and right coronary artery (RCA). The course of RCA was retro-aortic. There were no appreciable septal arteries to be ablated by alcohol injection. The patient was managed with implantable cardioverter-defibrillator (ICD) and metoprolol.

Conclusion: Single coronary artery (SCA) and HOCM are of great clinical significance as both of these conditions are independently associated with SCD. Medical management in form of beta blocker and ICD is an acceptable treatment strategy in appropriately selected symptomatic obstructive HCM. To the best of our knowledge, this is the first ever case report of RCA following a retro-aortic course arising from left main in a patient with obstructive HCM.