The need for permanent pacemaker after restoration of conduction following atrioventricular block: a retrospective cohort study

OBJECTIVE
A permanent pacemaker (PPM) is necessary for patients with a symptomatic third-degree or advanced second-degree atrioventricular (AV) block. An AV block due to medication use can often be reversed; however, subsequent relapse can occur and necessitate subsequent PPM implantation. The aim of this study was to explore the course and prognosis of patients with an AV block.

METHODS
This historical cohort study was conducted between January 2013 and June 2018. A total of 1900 patient records were analyzed and 1123 subjects with an AV block on admission were enrolled. The patients were categorized into 2 groups: Group 1 comprised patients with an AV block due to medication use (n=316, 28%) and Group 2 included patients with an AV block caused by other etiologies (n=807, 72%). Data of the cause of AV block, recurrence, and PPM implantation were analyzed. Patients in both groups who did not require a PPM during the index admission were followed up regarding subsequent implantation of a PPM.

RESULTS
AV conduction was recovered in 38 (12%) patients in Group 1 and 48 (6%) patients in Group 2 during the index hospitalization. However, recurrence of the AV block was observed in 18% of Group 1 patients and 40% of Group 2 patients. Only 25 patients in each group (4.5% of the whole study population) remained PPM-free during a median 3-year follow-up period.

CONCLUSION
The study findings suggest that drug-induced AV blocks may not be as benign as previously thought. The high relapse rate indicates that watchful follow-up may be required despite discontinuation of the responsible medication and that consideration of earlier PPM implantation in cases of early recurrence may be warranted.