Clinical outcomes of atrial high-rate episodes: an updated meta-analysis

Abstract Background Atrial high-rate episodes (AHRE) are commonly detected in individuals with cardiac implantable electronic devices. Outcomes of atrial high-rate episodes remain unclear in those without a prior history of atrial fibrillation. Purpose This study aims to evaluate clinical outcomes of atrial high-rate episodes in patients who have no prior history of atrial fibrillation. Methods PubMed, EMBASE, and Cochrane databases were searched through February 2024 for studies evaluating clinical outcomes in individuals with cardiac implantable electronic devices who experienced atrial high-rate episodes, compared to those who did not. Individuals who had a prior history of atrial fibrillation were excluded. Outcomes assessed were clinical atrial fibrillation, thromboembolic events, and all-cause mortality. A fixed-effects model was used to calculate risk ratios (RRs) with 95% confidence intervals (CI). A subgroup analysis of thromboembolic events was conducted based on the duration of atrial high-rate episodes. Results A total of 9 studies met inclusion criteria with a combined enrollment of 7440 patients. Compared to those who did not experience atrial high-rate episodes, those who did had significantly increased risks of clinical atrial fibrillation (RR 3.33; 95% CI 1.99 - 5.57; P < 0.0001) and thromboembolic events (RR 2.21; 95% CI 1.72 -2.85; P < 0.0001). The risk of all-cause mortality was similar between both groups (RR 1.19; 95% CI 0.95 – 1.49; P = 0.13). Subgroup analysis revealed an increased risk of thromboembolic events among atrial high-rate episodes ≥ 24 hours (RR 12.34; 95% CI 2.70 – 56.36) while atrial high-rate episodes lasting < 24 hours were insignificantly associated with thromboembolic events (RR 0.83; 95% CI 0.12 – 5.58). Conclusions Our study indicates a heightened risk of clinical atrial fibrillation and thromboembolic events among patients with atrial high-rate episodes, with no observed increase in mortality risk. Furthermore, our findings suggest that the duration of atrial high-rate episodes influences the risk of thromboembolism. Further studies are warranted to confirm our findings.