Methods: Data of 241 patients (108 males, 133 females, mean age: 53.7±12.3 years; range, 18 to 82 years) who underwent isolated mitral valve surgery with a median sternotomy between January 2009 and December 2019 were retrospectively analyzed. The patients were divided into three groups according to the surgical approach for mitral valve exploration as left atriotomy (n=47), transseptal (n=131), and superior transseptal (n=63). By scanning the hospital records, the origin of the sinoatrial nodal artery was determined in the coronary angiography images obtained before surgery. Postoperative rhythm changes were analyzed based on electrocardiography and telemetry recordings.

Results: Temporary pacing was required in 31 (49.2%) patients in the superior transseptal group, 40 (30.5%) patients in the transseptal group, and 12 (25.5%) patients in the left atriotomy group, indicating a statistically significantly higher rate in the superior transseptal group (p=0.013). Permanent pacemaker implantation was required in only one patient (superior transseptal), indicating no significant difference among the groups. The first-degree atrioventricular block was seen in 28 (44.4%) patients in the superior transseptal group, 42 (32.1%) patients in the transseptal group, and 13 (27.7%) patients in the left atriotomy group (p=0.130). The PR interval in the postoperative period was longer in the superior transseptal group than in the left atriotomy group in patients with the sinoatrial nodal artery originating from the right coronary artery (p=0.049). No significant difference was observed among the surgical approaches regarding the PR interval in patients with the sinoatrial nodal artery originating from the left circumflex coronary artery after surgery.

Conclusion: We believe that the choice of atriotomy in isolated mitral valve surgery and sinoatrial nodal artery variations do not affect permanent arrhythmia alone. Still, the superior transseptal approach causes the electrical conduction to slow down temporarily more than the left atriotomy and transseptal method.