Cardioneuroablation affects the cardiorespiratory coupling through the interference with baroreflex function

Background Cardioneuroablation (CNA) is used to treat reflex syncope by means of parasympathetic denervation of the cardiac conduction system. Cardiorespiratory coupling (CRC) plays an important role in optimizing pulmonary gas exchange and is believed to be vagally mediated. The acute impact of CNA on CRC remains unclear. Methods We studied 11 patients without structural heart or lung disease who underwent CNA for the treatment of cardioinhibitory vagally mediated syncope. We analyzed CRC using the following indices: a) amplitude, reflecting the overall magnitude of changes in heart rate (HR) during the respiratory cycle (Amp, ms), and b) efficiency, defined as the percentage of inspirations accompanied by HR increase (HRinc-ins, %), and expirations accompanied by HR decrease (HRdec-exp, %). For CRC analysis, we used continuous respiratory flow measurement and an electrocardiogram. Baroreflex sensitivity (BRS, ms/mmHg) was assessed with a sequential method using noninvasive hemodynamic monitoring. Both CRC and BRS were captured 48 hours apart, before and after CNA. Results After CNA, a significant reduction was observed in Amp (57 [30–131] vs 13 [7–16] ms, p=0.003, Figure 1), HRinc-ins (97.0 [77.8–100.0] vs 36.0 [14.3–63.2] %, p=0.003), and HRdec-exp (88.0 [78.1–97.6] vs 31.1 [21.4–65.8] %, p=0.008). Similarly, we noted a decrease in BRS (18.7 ± 17.4 vs 2.9 ± 1.2 ms/mmHg, p=0.010). Importantly, we observed a strong relationship between ΔBRS and ΔAmp following CNA (r=0.77, p=0.005). Conclusions Our findings indicate a substantial role of the cardiac parasympathetic system in the development of CRC and suggest an involvement of the baroreflex in this phenomenon. The marked decrease in all measures of CRC after CNA may help explain certain side effects of CNA (e.g., worsening of exercise tolerance seen in some patients) and highlights the need for further research into its long-term clinical effects.Fig 1.Bold line indicates average value