Firing patterns of muscle sympathetic neurons during short-term use of continuous positive airway pressure in healthy subjects and in chronic heart failure patients

Muscle sympathetic nerve activity (MSNA), hemodynamic and ventilatory parameters were obtained from 8 healthy middle aged subjects and 7 CHF patients. Action potentials (APs) were extracted from MSNA neurograms, quantified as AP frequency and classified into different sized clusters. While on CPAP at 10 cm H2O, multi-unit MSNA, AP frequency and mean burst area/min increased in healthy middle aged subjects (p < 0.05) whereas CPAP had no effect on these variables in CHF patients. In conclusion, the impact of CPAP on central hemodynamics in healthy individuals elicited a moderate activation of sympathetic neurons through increased AP firing frequency, whereas in CHF patients both hemodynamics and MSNA remained unaltered.