Cox-Maze IV Procedure Concomitant with Valvular Surgery In Situs Inversus Dextrocardia: A Single-center Experience in China.

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The use of ablation technologies made the Cox-Maze IV procedure (CMP-IV) technically easier, faster, becoming the gold standard for the surgical treatment of AF. However, the efficacy and safety of CMP-IV in situs inversus dextrocardia are largely unknown. This paper summarizes the CMP-IV procedure performed concomitantly with valvular surgery in patients with situs inversus dextrocardia at this institution. From February 2016 to September 2020, three dextrocardia patients with persistent AF and valvular diseases were referred to this institution for valvular and CMP-IV surgery. CMP-IV was performed using either cryoablation with a nitrous oxide (N2O)-based cryoprobe or a bipolar radiofrequency clamp and bipolar radiofrequency pen. Mechanical valve replacement or mitral vavuloplasty was performed in another patient in addition to tricuspid annuloplasty. Transmurality of the ablated atrial tissues was evaluated by electron microscopy. Heart function was assessed by transthoracic echocardiography. Cardiac rhythm was monitored by 24 h Holter at 3, 6, 12, 18, 24, and 48 months follow-up. All the AF was successfully eliminated in the ablation procedure without recurrence or other complications during hospitalization. The mean bypass and crossclamp times were similar in all the patients. The postoperative ventilator support time, the duration of stay in the ICU, and postoperative residence time were also not significantly different among the patients. Transmural atrial necrosis was detected in the ablated atrial tissues. Sinus rhythm maintenance was achieved at 3, 6, 12, 18, 24, and 48 months follow-up in all the patients. All valve protheses switched freely; no tricuspid regurgitation was observed. The results of the present study demonstrate that the CMP-IV is safe and effective in eliminating AF in dextrocardia patients concomitant with valvular surgery.