Predictive value of left atrial strain for new-onset atrial high-rate episodes in patients with permanent cardiac pacing

Introduction Atrial high-rate episodes (AHRE) are asymptomatic episodes of elevated atrial rate detected by implantable cardiac devices (CIEDs); AHRE are associated with increased risk of atrial fibrillation (AF) and AF-related clinical complications. Identifying patients at higher risk of developing AHRE is crucial for optimizing management and improving outcomes. Purpose To evaluate the predictive value of left atrial strain (LAS) parameters on future development of AHRE in patients undergoing pacemaker implantation. Methods This was a retrospective, single-center study including consecutive patients who underwent single- or dual-chamber pacemaker implantation between January 2021 and December 2023. Baseline pre-implantation echocardiographic assessment included speckle-tracking analysis of LAS and phasic functions, namely reservoir strain (LAS reservoir) and contraction strain (LAS contraction). AHRE were defined as asymptomatic episodes with an atrial rate >175 bpm lasting ≥5 minutes, detected through CIED monitoring. Primary endpoint was the accuracy of LAS reservoir and LAS contraction in predicting AHRE incidence during follow-up. Results A total of 283 patients (mean age 78.3±11.2 years, 32.8% female) were included. Mean CHA2DS2-VASc score was 3.77±1.62. Pacing indications were second- or third-degree atrioventricular block (62%) and sinoatrial node dysfunction (19%). At a mean follow-up of 28 months, AHRE occurred in 23% of patients. ROC analysis showed that LAS contraction had a greater area under the curve (AUC) for AHRE occurrence compared to LAS reservoir (0.76 [95% CI 0.70-0.83] vs. 0.65 [95% CI 0.57-0.73], p=0.001). The optimal cutoff value for LAS contraction was 10.2%, having sensitivity of 78%, negative predictive value (NPV) of 91%, specificity of 65% and positive predictive value (PPV) of 40%. Kaplan-Meier analysis revealed a higher incidence of AHRE in patients with LAS contraction <10.2% vs those with LAS contraction ≥10.2% (42% vs 10%; log-rank p<0.001). Multivariate analysis confirmed LAS contraction <10.2% as an independent predictor of AHRE (HR 5.8 [95% CI 3.1–10.7], p<0.001). Conclusion In patients with CIED, pre-implant LAS contraction is an independent predictor of future AHRE development, with high NPV. LAS contraction represents a very useful tool for identifying in clinical practice individuals at low risk for AHRE. Pre-implantation atrial mechanics assessment may enhance risk stratification and optimize clinical management.