Same-same, but different? Postoperative rhythm disturbances and other analysis after rotational Z-flap vs. patch...

Surgical correction of sinus venosus atrial septal defects (SVASD), often associated with partial anomalous pulmonary venous return (PAPVR), is characterized by low mortality but carries a risk of postoperative rhythm disturbances due to the proximity of the sinus node. This study aimed to compare the clinical outcomes and incidence of postoperative arrhythmias between two surgical techniques: the conventional patch repair (baffle) and the rotational "Z" flap technique.

A retrospective, single-center non-inferiority analysis was conducted on 110 patients (adult and pediatric) who underwent isolated SVASD correction between 2000 and 2025 in northern Bavaria, Germany. Patients with preoperative arrhythmias or concomitant procedures were excluded. Subjects were divided into two cohorts: the baffle group (n = 70) and the "Z" flap group (n = 40). The primary endpoint was documented postoperative rhythm disturbance at 3-6 months follow-up on EKG. Secondary endpoints included operative times, residual shunts, and SVC (Superior vena cava) stenosis.

Operative times were significantly shorter in the "Z" flap group compared to the baffle group (Total time: 182.6 vs. 209 min; Bypass time: 71.4 vs. 96.1 min; Cross-clamp time: 35.7 vs. 46 min; all p < 0.05). Postoperative rhythm disturbances occurred in 54.5% of the total population, with the right bundle branch block (40.1%) being the most frequent. Notably, the "Z" flap group showed a significantly higher incidence of sinoatrial block with atrio-ventricular junctional rhythm (17.5% vs. 4.3%; p = 0.035; OR = 4.47). No patients required permanent pacemaker implantation, and no significant differences were found regarding residual shunts or superior vena cava stenosis.

Both surgical methods are effective and contain inherent advantages and disadvantages for SVASD correction. While the "Z" flap technique is surgically more efficient with shorter ischemic times, it is associated with a significantly higher risk of developing postoperative junctional rhythms compared to the conventional baffle repair.