Background: Atrial fibrillation (AF), whether paroxysmal or persistent, can cause stroke and mortality and impact on the quality of life. These days, permanent pacemakers can provide intracardiac electrograms; any tachyarrhythmias detected are reported as atrial high-rate events (AHRE), which could lead to the identification of subclinical AF. However, there are still no data on the prevalence of AHRE or on their correlation with stroke in the Thai population.

Objective: The primary and secondary outcomes were to evaluate the prevalence of AHRE in patients who underwent cardiac implantable electronic device (CIED) surgery in the Thai population, and the correlation of AHRE with stroke, respectively.

Materials and Methods: The authors conducted a retrospective, cohort, descriptive study on patients who had undergone a dual-chamber CIED implantation during a 7-year period, with a median follow-up of 5.8 years.

Results: One hundred ninety-six patients who had undergone a dual-chamber CIED implantation and been followed up for 5.8 years were retrospectively reviewed. In the case of the primary outcome, AHRE were detected in 82 of the patients (41.8%). As to the secondary outcomes, 20 patients (10.2%) were lost to follow-up during the study period. Stroke occurred in five out of the 78 patients in the AHRE group (6.4%), whereas stroke occurred in one out of the 98 patients in the non-AHRE group (1.0%); however, there was no statistically significant difference (p=0.089) between the two groups. The mortality rates of the AHRE and non-AHRE groups were also nearly equal (23.4% vs. 23.5%; p=0.989).

Conclusion: The present study examined AHRE, which were assumed to be indicative of subclinical AF. They were found in a sizeable proportion (41.8%) of the Thai study population who had been implanted with a dual-chamber CIED. No statistically significant association was found between AHRE and either stroke or the mortality rate.

Keywords: CIED, Atrial fibrillation, Prevalence