Conduction disturbance requiring permanent pacemaker implantation after TAVR was associated with the anatomical localization of MAC rather than its overall severity. A retrospective analysis published in the European Journal of Cardio-Thoracic Surgery evaluated the impact of MAC severity and segmental distribution on clinical outcomes after TAVR.

The study included 642 consecutive patients who underwent TAVR between 2016 and 2021. Patients with prior permanent pacemaker implantation were excluded. Preprocedural computed tomography was used to assess MAC severity and segmental distribution. Patients were classified as having no MAC, mild or moderate MAC, or severe MAC. The median follow-up duration was 2.1 years.

Severe MAC was present in 15% of patients. New permanent pacemaker implantation due to complete atrioventricular block occurred in 10.9% of the cohort. All-cause mortality within three years occurred in 24.6% of patients. Three-year survival rates were comparable across MAC severity groups (68.7%, 68.0%, and 69.6%; p not significant). Neither MAC severity nor overall segmental distribution independently predicted mortality.

Pacemaker implantation occurred more frequently in patients with severe MAC at 20%. In multivariable analysis, MAC localized to the A3 segment, rather than overall MAC severity, independently predicted permanent pacemaker implantation after TAVR (odds ratio 5.10; p < 0.001).