Abstract
BACKGROUND: Atrial high-rate episodes (AHREs) detected by cardiac implantable electronic devices are associated with a higher risk of developing subsequent atrial fibrillation. Thus, risk stratification for AHREs is essential to guide patient management and improve outcome. Left atrial strain (LAS) parameters have been proposed as markers of atrial mechanical dysfunction, but their predictive value for AHRE prediction is not definitely established. METHODS: We performed a retrospective, single-center study on consecutive patients undergoing pacemaker implantation. Pre-implant echocardiographic assessment included the measurement of LAS parameters. AHREs were defined as asymptomatic episodes with atrial rate > 175 bpm lasting ≥ 5 min by pacemaker evaluation. Primary endpoint was the predictive accuracy of LAS values for AHRE occurrence during follow-up. RESULTS: A total of 269 patients (age 78.0 ± 11.2 years; CHA₂DS₂-VASc score 3.8 ± 1.6) were included. Median follow-up was 28 months. ROC analysis showed that LAS contraction had superior predictive value for AHREs than LAS reservoir (AUC 0.75 vs. 0.63, p = 0.001). A 10.2% cutoff of LAS contraction had sensitivity of 77%, specificity of 64%, and negative predictive value (NPV) of 90% for AHRE occurrence. Kaplan-Meier analysis showed a higher AHRE incidence in patients with LAS contraction < 10.2% (45% vs. 10% in those with LAS contraction ≥ 10.2%; log-rank p < 0.001). Multivariate analysis confirmed LAS contraction < 10.2% as an independent predictor of AHREs (adjusted hazard ratio [aHR] 5.0 (95% CI 2.7-9.3); p < 0.001). The risk increase was even higher when a LAS contraction < 10.2% was associated with age ≥ 70 years (aHR 16.3; 95% CI 2.0-131.7; p = 0.009). CONCLUSIONS: In patients with a permanent pacemaker, pre-implant LAS contraction by echocardiography is an independent predictor of future AHRE development, with a very high NPV. The evaluation of LAS contraction may represent a valuable tool for identifying in clinical practice those individuals at low risk for AHREs.