Do beta-blockers reduce sympathetic activity in patients with mild sleep breathing disorder without CPAP therapy?

Background: Sympathetic overdrive after apnea and hypopnea events is thought of as a mechanism that increases the risk of cardiovascular morbidity in patients with sleep breathing disorder (SBD). This study questioned if beta-blocker (BB) therapy without CPAP therapy could decrease sympathetic drive in patients with mild SBD. Method: Retrospectively, the medical data of 90 patients with mild SBD, AHI: 5-15 who had PSG in the sleep lab including demographic co-morbidities, medications affecting heart rate variability and central respiratory drive, PSG parameters, average RR interval, low and high-frequency powers (LF, HF) were collected. The two-tailed t-test was applied to the interested data. Results: There were 90 patients (38 females) who had a mild SDB with a mean AHI of 9.37. 24 patients (13 females) were taking BB. In patients on BB therapy compared with patients, not on BB, AHI, PLMS index, arousal index, Oxygen desaturation index, sleep efficiency and total sleep time were not significantly different. The low-frequency power, an indicator of sympathetic activity, was 8180 ms2 vs 13572 ms2in patients on BB vs patients not on BB. (P-value: 0.003, mean of -5392, 95% CI: -8838 to 1947). Conclusion: Our data suggest that beta-blocker therapy without CPAP therapy in patients with mild SBD can significantly reduce sympathetic activity after apneas and hypopneas.