Komsing Methavigul, MD¹

Objective: To study the effect of COVID-19 infection on ventricular pacing threshold among patients with pacemakers.

Materials and Methods: Patients with pacemakers were retrospectively recruited at the device clinic, Central Chest Institute of Thailand between January 2022 and September 2023. Those patients were classified into two groups according to a history of previous COVID-19 infection. The primary outcome was the proportion of patients with high ventricular pacing threshold, and the secondary outcome was the mean ventricular pacing threshold between both groups. The chi-square or Fisher’s exact test was used to compare the primary outcome between both groups. The independent t-test was used to compare the secondary outcome between both groups.

Results: One hundred twenty-two patients were enrolled. The average age was 69.4 years. Nearly 60% of these patients were implanted with pacemakers because of atrioventricular block. Of the 122 patients, there were 54 patients in the COVID-19 group and 68 patients in the non- COVID-19 group. The present study demonstrated that two patients (3.7%) in the COVID-19 group and two patients (2.9%) in the non-COVID-19 group had high ventricular pacing threshold, respectively. There were more patients with high ventricular pacing threshold in the COVID-19 group than those in the non-COVID-19 group with no statistical significance (adjusted odds ratio 1.55, 95% confidence interval [CI] 0.19 to 12.81, p=0.69). Compared with the non-COVID-19 group, there were comparable mean ventricular pacing threshold in the COVID-19 group, with a mean absolute difference of –0.03 (95% CI –0.14 to 0.09, p=0.65).

Conclusion: Patients with pacemakers had no significant increase in ventricular pacing threshold after recovering from COVID-19 infection.

Received 17 June 2025 | Revised 8 December 2025 | Accepted 9 December 2025

DOI: 10.35755/jmedassocthai.2026.2.03206