Successful transvenous implantable cardioverter-defibrillator implantation supported by preceding 3D electro-anatomical mapping for a ventricular fibrillation survivor with surgically repaired congenitally corrected transposition of the great arteries: a case report.

Background: The atrial sites suitable for lead placement are limited after complex surgical atrial procedures, and lead placement can be challenging in patients with congenitally corrected transposition of the great arteries (ccTGA) after intracardiac repair.

Case summary: A 34-year-old man with ccTGA, who had undergone a double-switch operation with combined Senning and Jatene operations at the age of 14 was transferred to us. He experienced faintness and suffered cardiopulmonary arrest, and electrocardiography revealed ventricular fibrillation. After conversion to sinus rhythm by urgent external defibrillation, sinus bradycardia was revealed. Electrophysiological study was done using a three-dimensional (3D) mapping system (Ensite®) to evaluate the electrical condition of atria and to decide whether atrial lead can be transvenously placed. The electrical potential of the functional right atrium was good in the lateral or posterior wall, but the threshold was high. By contrast, the roof of the functional right atrium beyond cavoatrial junction was characterized by low voltage, but in a limited region of the roof of right atrium, the threshold was satisfactory and the electrical potential was normal. Thus, 3 weeks later, we implanted a transvenous implantable cardioverter-defibrillator (ICD). We used a 3D mapping system to place the atrial lead in the limited region of the roof of the right atrium mentioned above, the threshold was 0.7 V.

Discussion: Electrophysiological examination using a 3D mapping system before implantation of a dual-chamber ICD is useful because atrial sites suitable for lead placement are limited in patients.