[Changes of the characteristics of sleep apnea in heart failure patients and the associated factors].

OBJECTIVE

To investigate the changes of the characteristics of sleep apnea in heart failure patients with periodic breathing disorder and to explore the influencing factors.

METHODS

According to the characteristics of sleep apnea after polysomnography (PSG) for 2 nights, 54 patients with heart failure were divided into 3 groups: obstructive sleep apnea (OSA), central sleep apnea (CSA) and OSA-CSA switching groups, with 18 patients each. t test was used for comparison between the first and the second PSG data, left ventricular ejection fraction (LVEF), periodic breathing cycle length (PBCL) and lung to finger circulation time (LFCT) in the same patient. Analysis of variance was performed for comparison within groups and Pearson correlation test was used for correlation analysis between 2 variables.

RESULTS

When the events of sleep apnea changed from OSA to CSA, the mean wake and sleep stage II (S2) PtcCO(2) decreased significantly [(41.0 +/- 1.3) cm H(2)O vs (34.9 +/- 1.0) cm H(2)O, 1 cm H(2)O = 0.098 kPa, P < 0.01;(42.1 +/- 1.2) cm H(2)O vs (36.3 +/- 1.1) cm H(2)O, P < 0.01], while PBCL and LCFT increased significantly [(51.9 +/- 2.1) s vs (62.3 +/- 1.9) s, P < 0.01, (54.4 +/- 1.8) s vs (65.3 +/- 1.6) s, P < 0.01]. Furthermore, there was a significant decrease in LVEF [(32.1 +/- 2.5)% vs (19.9 +/- 3.5)%, P < 0.05], and LVEF was negatively correlated with PBCL and LFCT (r = 0.687, P < 0.05;r = -0.591, P < 0.05). When sleep apnea changed from CSA to OSA, the mean wake and S2 PtcCO(2) increased significantly [(39.2 +/- 0.5) cm H(2)O vs (42.7 +/- 1.0) cm H(2)O, P < 0.05], while PBCL and LFCT decreased significantly [(61.5 +/- 3.4) s vs (49.7 +/- 2.8) s, P < 0.05, (66.1 +/- 2.1) s vs (52.1 +/- 1.6) s, P < 0.01)]. In addition, there was a negative correlation between PtcCO(2) and PBCL (r = -0.586, P < 0.05). However, PtcCO(2) showed no significant correlation with LFCT (r = -0.381, P > 0.05). There were no statistical differences between the first and the second mean wake and S2 PtcCO(2), PBCL and LFCT in the OSA and the CSA group, but AHI showed a significant correlation with LVEF in the CSA group (r = -0.474, P < 0.05).

CONCLUSIONS

The characteristics of sleep apnea can change when periodic breathing happens in heart failure patients with OSA or CSA. The change can be affected by wake and sleep PtcCO(2), PBCL and LFCT, and possibly by heart function.