Congenitally corrected transposition of great vessels with infundibular pulmonary stenosis with ventricular septal defect, presenting with atypical atrioventricular nodal reentrant tachycardia: a rare association

Congenitally corrected transposition of great vessels (CCTGV) is a rare congenital heart disease (CHD) accounting for <1% of CHDs. CCTGV with infundibular pulmonary stenosis (PS) with ventricular septal defect (VSD) is part of Fallot's physiology. It is known to be associated with bradyarrhythmias like atrioventricular (AV) blocks, and acquired complete AV block occurs at a rate of 2% per year. Patients can have left-sided accessory pathways, which may cause atrioventricular reentrant tachycardia (AVRT). Tachyarrhythmias like atrioventricular nodal reentrant tachycardia (AVNRT) are very rare in such patients. A 30-year-old woman, a known case of CCTGV with PS with VSD, not corrected surgically and not on any drugs, presented with the syndrome of paroxysmal supraventricular tachycardia without hemodynamic compromise. Electrocardiogram showed atypical AVNRT. She was pharmacologically cardioverted to normal sinus rhythm with adenosine. CTGV with PS with VSD known to be associated with AV blocks, and preexcitation can sometimes present with atypical AVNRT.