Cardiac pacing in congenitally corrected transposition of the great arteries: technique, challenges, and outcome

Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart disease characterized by atrioventricular and ventriculoarterial discordance, frequently associated with ventricular L-looping, abnormal conduction anatomy, and a high burden of atrioventricular block. In patients without prior double-switch repair, standard transvenous pacemaker implantation may resemble conventional implantation in some respects; however, procedural challenges arise when ccTGA is accompanied by dextrocardia, situs inversus, prior intracardiac repair, prosthetic valves, abnormal venous access, or the need to target the subpulmonary morphologic left ventricular septum for physiologic pacing. In the present cohort, dextrocardia and mirror-image anatomy were major contributors to procedural complexity. We retrospectively reviewed patients with ccTGA who underwent pacemaker implantation at Beijing Anzhen Hospital between 2018 and 2024. Clinical characteristics, pacing strategies, procedural details, and follow-up outcomes were analyzed. A total of 12 patients (mean age 34.5 years [range: 12–53 years]; 6 with dextrocardia) underwent pacemaker implantation for atrioventricular block. Eleven patients underwent transvenous pacemaker implantation, including 2 with left bundle branch pacing supported by documented implantation criteria, and 1 patient underwent leadless pacemaker implantation. Preprocedural cardiac CT and intraoperative angiography were critical for lead navigation within the subpulmonary morphologic left ventricle and abnormal septal anatomy. Over a mean follow-up of 3.5 years (range: 0.4-7 years), one patient experienced atrial lead dislodgement; no major complications occurred. Pacemaker implantation in patients with ccTGA is feasible when guided by careful anatomical assessment and a tailored pacing strategy. A pacing-strategy classification that distinguishes conventional morphologic LV septal pacing, morphologic LV apical pacing, documented left bundle branch pacing, deep septal pacing, and leadless septal pacing may better describe procedural outcomes in this challenging population, although interpretation of systemic morphologic right ventricular function and systemic tricuspid regurgitation during follow-up is limited by incomplete echocardiographic data.