CAD in Adults With CHD

A 29-year-old man with double outlet right ventricle, transposition of the great arteries, ventricular septal defect, and pulmonary stenosis was treated with the Rastelli procedure as an infant. He underwent right ventricle (RV) to pulmonary artery (PA) conduit replacement in his teenage years and successfully underwent Melody transpulmonary valve (Medtronic, Inc., Minneapolis, MN) implantation 3 months prior to presentation due to conduit stenosis with a gradient of 70 mm Hg in the presence of New York Heart Association Class III symptoms. The patient presented (3 months post-surgery) with near syncope and significant chest pain while exercising on his treadmill at home. He was diaphoretic, felt unwell, and presented to the emergency department with hypotension and wide complex tachycardia at a rate of 200 bpm. The emergency department physician cardioverted the patient electrically into sinus rhythm. A physical exam revealed displaced apex and a precordial heave. He had rales bilaterally, a single S2, and an S3. His pertinent laboratory findings included troponin of I7.8 ng/ml and creatine kinase of 530 units/L. A post-cardioversion electrocardiogram showed q waves inferiorly but no evidence of ST-segment elevation myocardial infarction (MI).

What was the most likely missed step in work-up of this patient prior to transpulmonary valve implantation?

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