Cardioneuroablation changes the type of vasovagal response in patients with asystolic reflex syncope.

Abstract Background Cardioneuroablation (CNA) has been recently proposed as a new therapy in patients with asystolic vasovagal syncope (VVS) caused by parasympathetic overactivity. Objective To assess the impact of CNA on the type of VV response during tilt testing (TT). Methods The study group consisted of 20 patients (7 males, mean age 38 ± 9). All patients had a history of syncope due to asystole and confirmed asystolic VVS at baseline TT (TT1). CNA was performed in the right and left atrium. The second TT (TT2) and Holter ECG were performed three months later. All patients completed one-year follow up. Results At TT1, twenty patients had cardioinhibitory syncope and 1 had mixed VVS with asystole > 3 s. During one-year follow-up no spontaneous syncopal episodes were noted. At TT2, 6 patients had no syncope whereas the remaining 13 had syncope – twelve due to vasodepressor mechanism and only one due to asystole. Mean heart rate after CNA was significantly faster and heart rate variability parameter (SDNN) lower than before the procedure (82 ± 9 vs 69 ± 11 beats/min, p = 0.0003 and 74 ± 22 vs 143 ± 40 ms, p = 000001, respectively). These changes were similar in those who fainted during TT2 and those who did not (84 ± 10 vs 81 ± 5 beats/min, p = NS and 72 ± 24 vs 72 ± 19 ms, p = NS, respectively). Conclusions CNA profoundly affects type of VV reaction causing normalization of the response to tilting or changing cardiodepression to vasodepression. Changes in heart rate and heart rate variability are consistent with attenuation of parasympathetic activity.