Short- and Mid-Term Effects of Transcatheter Aortic Valve Replacement on Heart Rate Variability in Patients With Aortic Valve Stenosis

Background Heart rate variability (HRV) reflects autonomic nervous system balance and has emerged as a potential prognostic marker in cardiovascular diseases. However, the relationship between HRV and mortality following transcatheter aortic valve replacement (TAVR) remains unclear. Method This prospective cohort study included 230 patients with symptomatic severe aortic stenosis who underwent TAVR between June 2022 and June 2024. Twenty-four-hour Holter electrocardiography recordings were obtained one day before and at 3 months after the procedure to assess HRV using both time- and frequency-domain parameters. Results Among the 230 patients enrolled, the 12-month all-cause mortality rate was 14.3%. Among frequency-domain parameters, the pre-TAVR low frequency/high frequency (LF/HF) ratio improved markedly from 2.20±1.45 to 1.54±0.85 (p<0.001). In the time domain, standard deviation of NN intervals (89-103 ms, p=0.027), standard deviation of the averages of NN intervals (68-83 ms, p=0.003), and percentage of successive RR intervals (10.0%-12.0%, p=0.036) all showed significant improvements, while root mean square of successive RR interval differences remained unchanged. The pre-TAVR LF/HF ratio was significantly lower in survivors and provided the best discrimination for 1-year mortality prediction (area under the curve 0.815; 95% confidence interval [CI] 0.750-0.881). Calibration analysis confirmed excellent predictive accuracy (C-index, 0.81; Brier score, 0.104; pseudo-R2, 0.285). Patients with a pre-TAVR LF/HF ratio>1.34 had significantly lower mortality at follow-up (hazard ratio [HR] 0.103; 95% CI 0.042-0.250; log-rank p<0.001), and this association remained significant in landmark analysis beyond 3 months (HR 0.163; log-rank p<0.001). Conclusions HRV parameters provide meaningful prognostic information in patients undergoing TAVR. Among them, a reduced pre-TAVR LF/HF ratio is independently associated with increased 1-year mortality and may serve as a practical, non-invasive marker for risk stratification.