Abstract 15258: Associations Between HV Interval and Incident Pacemaker Implant in Over 3,000 Patients

Introduction: The His Bundle-Ventricular (HV) interval is a measure of the conduction time between the bundle of His and the ventricular myocardium and has been shown to predict atrioventricular block (AV) in patients with conduction disease. Routine HV interval measurement during electrophysiology (EP) studies affords an opportunity to assess the utility of the HV interval as a marker for future conduction disease in a broader sample.

Methods: We analyzed consecutive EP studies from over 600,000 primary care and cardiology patients in the Mass General Brigham network. We assessed associations between HV interval and incident pacemaker (PPM) implantation in Cox proportional hazard models adjusted for age, sex, hypertension, hyperlipidemia, diabetes mellitus, coronary artery disease, heart failure, atrial fibrillation, and stroke. Person-time began 30 days after index EP study to exclude PPM implant triggered by study findings. Cumulative risk was plotted using Kaplan-Meier curves and the functional form of the relationship between HV and PPM was fit using multivariable-adjusted splines.

Results: Of 22,019 individuals with at least one EP report, we identified 3,283 patients (age 61.1±13.6, 63% male, 91.6% White) with an HV interval measurement. In multivariable-adjusted models, a longer HV interval was associated with increased risk of PPM implant (hazard ratio [HR] 1.24 per 10ms increase, 95% CI 1.08-1.43). When assessed at binary cutoffs, there were progressively larger increases in risk of incident PPM implantation (HV ≥55: HR 1.94 (1.28-2.93); HV ≥70: HR 2.18 (1.04-4.56); HV ≥100: HR 7.75 (2.18-27.5)). PPM implant risk increased linearly until 90ms, above which risk increased sharply (Figure).

Conclusions: Among patients undergoing EP study, a prolonged HV interval was a strong risk marker for incident PPM implantation. Patients found to have a prolonged HV interval during EP study merit close observation for the development of overt conduction disease.