Sudden death in transposition of the great arteries with atrial switch surgery: Autopsy evidence of acute myocardial ischemia despite normal coronary arteries

Abstract Background Sudden death is the leading cause of mortality in patients with transposition of the great arteries (TGA) and atrial switch surgery. Understanding underlying mechanisms could contribute to identifying high-risk patients and preventing such catastrophic deaths. Methods A total of 144 adults (≥18 years) with TGA and atrial switch surgery were followed at our adult congenital center since 1989. Four patients were excluded: two with double-outlet right ventricles and two with subsequent arterial switch surgery in childhood. Results Of the remaining 140 patients, age 37.6 ± 7.8 years, 37.1% female, 8 (6%) had a cardiac arrest of presumed arrhythmic etiology of whom 3 were resuscitated. The arrests occurred in 3 women and 5 men at age 30.5 ± 8.6 (range 22 to 50) years. None had established coronary artery disease, sustained ventricular arrhythmias, or syncope. Four (50%) had atrial arrhythmias and 6 (75%) had at least moderate systemic right ventricular dysfunction. For 5 patients in whom circumstances surrounding the arrests were documented, 3 occurred on exertion, 1 after consuming recreational methamphetamine, and 1 in the context of an atrial tachyarrhythmia. Autopsies were performed in 2 of 5 patients. Both revealed acute massive myocardial infarction of the hypertrophied systemic right ventricle with normal coronary arteries and chronic subendocardial ischemic lesions. Conclusion This is the first report to provide histopathological evidence in support of a myocardial ischemia hypothesis as a cause of sudden death in this patient population, despite the absence of coronary atherosclerosis.