Temporal Changes in Nonlinear Heart Rate Variability Following Pulmonary Vein Isolation for Paroxysmal Atrial...

Heart rate variability (HRV) provides insights beyond standard electrocardiography (ECG). Although prior studies have shown altered short-term linear HRV in patients with paroxysmal atrial fibrillation (PAF) after pulmonary vein isolation (PVI), long-term nonlinear changes are unclear. This study aimed to investigate longitudinal nonlinear HRV changes before and after PVI in PAF patients.

Forty-two drug-refractory PAF patients (55.50 ± 9.53 years old, 11 females) undergoing PVI were enrolled. Holter ECG was recorded before, at 1-3 months, and at 6-12 months post-PVI. Nonlinear HRV variables including multi-scale entropy (MSE), detrended fluctuation analysis (DFA), and Poincaré plot analysis, were analyzed.

Significant reductions in standard deviation (SD)1, SD1/SD2, MSE _1-5, and MSE _6-20 were found 6-12 months post-PVI compared to baseline. SD2, MSE _{slope 5}, and DFA _{slope 1} decreased at 1-3 months post-PVI but showed significant increases at 6-12 months post-PVI. DFA _{slope 2} increased significantly after PVI.

Long-term fractal correlation properties (DFA _{slope 2}) increased significantly following PVI. Heart rate complexity (MSE _1-5 and MSE _6-20) and vagal activity (SD1) decreased significantly after PVI, whereas short-term fractal correlation properties (DFA _{slope 1}) and short-term heart rate complexity dynamics (MSE _{slope 5}) decreased at 1-3 months post-PVI and then increased by 6-12 months post-PVI. These results highlight the significant and varied effects of PVI on cardiac neuromodulation and complexity, as demonstrated by HRV parameters.