Reduced Heart Rate Variability May Predict Left Atrial Appendage Thrombus or Spontaneous Echo Contrast in Patients With Non- Valvular Atrial Fibrillation

Objectives: Heart rate variability (HRV) has been associated with cardiovascular disease risk factors and adverse outcomes. Current evidence suggests that the presence of left atrial appendage thrombus (LAAT) or spontaneous echo contrast (SEC) is associated with an increased risk for subsequent stroke in patients with non-valvular atrial fibrillation (NVAF). This study aimed to investigate the relationship between HRV and LAAT/SEC in patients with NVAF. Methods 347 patients with NVAF treated at Nanfang Hospital in China from Jan 2019 to Dec 2021 were retrospectively analyzed. All patients recruited underwent laboratory evaluation, Transesophageal echocardiography (TEE) and 24h Holter electrocardiography .We explored the differences in demographic, clinical characteristics and HRV parameters between the two groups with and without LAAT/SEC. Results In this study, 82 patients (23.6%) had LAAT/SEC. The LAAT/SEC group had lower HRV parameters. After controlling for confounding factors, both SDNN (OR 0.973, 95%CI 0.959–0.987, P < 0.001) and SDANNI (OR 0.985, 95%CI 0.971–0.99, P < 0.001) were found to be independent predictors of LAAT/SEC. Receiver operating characteristic curve analysis revealed that the optimal cutoff value of the SDNN and SDANNI for predicting LAAT/SEC were 132 and 91, respectively. The risk of LAAT/SEC in patients with SDNN ≤ 132 and SDANNI ≤ 91 was 4.064 and 4.083-fold higher than in patients with SDNN > 132 and SDANNI > 91, respectively. Conclusion Reduced HRV was inversely correlated with LAAT/SEC in patients with NVAF, suggesting it has huge prospects for clinical application to predict the presence of LAAT/SEC. Early identification and intervention in NVAF patients with decreased HRV may help to decrease the risk of thrombosis.