# High incidence of permanent pacemaker after Cox-maze IV and mitral valve surgery: a nationwide registry-based study

## TL;DR

This study found that patients who had Cox-maze IV surgery with mitral valve surgery were more likely to need a permanent pacemaker compared to those who had mitral valve surgery alone.

## Contribution

The study provides new evidence on the increased long-term risk of permanent pacemaker implantation following Cox-maze IV and mitral valve surgery.

## Key findings

- CMIV patients had a doubled adjusted risk of requiring a pacemaker after 8 years compared to patients without CMIV.
- Sinus node dysfunction was the main reason for late pacemaker implantation in CMIV patients.
- Atrioventricular block II/III was the most common early pacemaker indication in both groups.

## Abstract

This study evaluated the long-term risk of permanent pacemaker implantation following Cox-maze IV (CMIV) and concurrent mitral valve surgery.

A retrospective, nationwide, registry-based analysis was conducted on postoperative permanent pacemaker implantation in 397 patients with symptomatic mitral valve insufficiency and atrial fibrillation who underwent CMIV and mitral valve surgery in Sweden between 2009 and 2017. They were compared to a registry group of 346 patients with atrial fibrillation who underwent mitral valve surgery without surgical ablation during 2014–2017. The follow-up ended on 30 September 2022.

CMIV patients were on average 4 years younger and had lower surgical risk than registry patients. More CMIV patients underwent early (<30 days) pacemaker implantation (13.3% vs. 5.5%, P = 0.002). CMIV patients had a doubled adjusted risk of requiring a pacemaker compared to registry patients after 8 years [HR 1.96, 95% CI 1.27–3.04]. In the CMIV group, 22% (95% CI 18–26%) had a pacemaker by 5 years, increasing to 27% (95% CI 22–31%) by 8 years, compared to 13% (95% CI 10–17%) at both time intervals in the registry group. Atrioventricular block II/III accounted for >60% of early pacemaker indications in both groups, and sinus node dysfunction was the indication for late pacemaker implantation in 48% in the CMIV group.

Patients undergoing CMIV concomitant with mitral valve surgery have a higher rate of postoperative pacemaker implantation compared to patients with atrial fibrillation undergoing mitral valve surgery alone. Sinus node dysfunction was the main indication for late pacemaker among CMIV patients.

Atrial fibrillation is associated with an increased risk of stroke, heart failure and mortality [1–3].