The Relationship Between Heart Rate Variability Parameters and Atrioventricular Nodal Reentrant Tachycardia

Introduction: Heart rate variability (HRV) is associated with sympathetic tone. Studies have disputed the interpretation of the low frequency (LF) and low/high frequency (LF/HF) ratio for the indication of sympathetic cardiac control and autonomic balance. This study aims to investigate the association between HRV parameters and atrioventricular nodal reentrant tachycardia (AVNRT) and observe the effect of autonomic nervous system on AVNRT. Patients and Methods: In total, 354 subjects with palpitations underwent the electrophysiological study (EPS). Most (71%; 253/354) patients had at least an ambulatory Holter ECG recording of 24 h. As a consequence of the exclusion criteria, 160 individuals were classified into two groups: control group (no arrhythmia induced, n= 90) and AVNRT group (n= 70). Results: Daytime and nighttime LF and LF/HF ratio were significantly higher in the AVNRT group (p< 0.05) than in the control group. Interestingly, daytime ultra-LF, very LF, and total power were significantly lower in the AVNRT group. Conclusion: AVNRT is associated with altered sympathovagal balance. Furthermore, increased LF and LF/HF may be indicative of enhanced sympathetic activity in patients with AVNRT because of inhomogeneous ventricular activation via the slow accessory pathway