Aims: This study investigated whether abnormal cardiac sympathetic nerve activity (SNA) is associated with the severity of central sleep apnoea (CSA) and whether adaptive servo-ventilation (ASV) therapy can improve cardiac SNA in heart failure (HF) patients with predominant CSA.
Methods and results: Overnight polysomnography was conducted to diagnose CSA. Cardiac SNA was analysed by [123I]metaiodobenzylguanidine scintigraphy in 26 consecutive HF patients with predominant CSA. Of the 26 patients, 10 agreed to ASV therapy. Cardiac SNA was analysed 6 months after initiating ASV based on a non-randomized protocol. The apnoea-hypopnoea index and central apnoea index were significantly correlated with the washout rate (WR) and a delayed heart to mediastinal (H/M) ratio, suggesting that SNA is associated with abnormal breathing patterns. The WR, H/M ratio, plasma BNP level, and LVEF were significantly improved (WR, 40.0 ± 11.6% vs. 34.6 ± 11.4%, P = 0.046; H/M ratio, 1.5 ± 0.1 vs.1.8 ± 0.3, P = 0.013; ln BNP, 5.4 ± 1.0 vs. 4.6 ± 1.2, P = 0.007; and LVEF, 43.8 ± 10.4% vs. 47.0 ± 10.6%, P < 0.001) in the ASV group patients, but not in the non-ASV group patients. Multiple linear regression analyses showed that a decreased WR was strongly associated with an increased LVEF (coefficient = -0.454, P = 0.013).
Conclusions: Abnormal cardiac SNA could be significantly correlated with the severity of CSA in HF patients. ASV therapy might improve cardiac function in these patients by partially mediating cardiac SNA regulation.
Keywords: Adaptive servo-ventilation; Cardiac sympathetic nerve activity; Heart failure; Sleep-disordered breathing; [123I]MIBG cardiac scintigraphy.