Objective: Radiofrequency catheter ablation (RFCA) is the curative treatment of choice for many cardiac arrhythmias and may cause myocardial injury and inappropriate sinus tachycardia. This study aimed to determine the delayed injury of autonomic nerve after RFCA.
Methods: Spectral analysis of heart rate variation on 24-hour Holter electrocardiogram recordings was carried out in 86 cases (39 women, 47 men; mean age, 42 years; range, 17-67 years) with paroxysmal supraventricular tachycardia 1 hour before and 1 year after successful RFCA (WPW type A = 31; Wolf-Pakinson-White Syndrome type B = 9; atrioventricular [AV] nodal tachycardia = 46; group A: septal accessory pathway + AV nodal tachycardia [n = 52], group B: free wall accessory pathway [n = 34]).
Results: Heart rate variation data (time domain and frequency domain) in group A 1 year after RFCA; including very low frequency; low frequency (LF); high frequency (HF); R-R interval; root mean squared successive difference interval; the percentage of sinus cycles differing from preceding cycle by more than 50 milliseconds (PNN50); and delta very low frequency, delta LF, delta HF, delta root mean squared successive difference interval and delta PNN50 significantly decreased, compared with that before the procedure. LF/HF, SD of all normal-to-normal intervals, and SD of 5-minute average normal-to-normal intervals were not significantly changed after RFCA. Heart rate variation data in group B 1 year after RFCA was not significantly changed, compared with that before the procedure.
Conclusion: Radiofrequency catheter ablation operation in site of septal accessory pathway and AV node slow pathway can cause delayed injury of autonomic nerves. Heart rate variation decrement 1 year after RFCA and persistent inappropriate sinus tachycardia post RFCA resulted from delayed injury of cardiac vagus nerve by radiofrequency current.