Central sleep apnea (CSA)

Central sleep apnea (CSA)

Central sleep apnea (CSA) is a respiratory disorder that causes difficulties in breathing during sleep, and it affects about 30% of people with congestive heart failure (CHF). Also, heart transplant, which cures CHF and CSA, has proved effective in some patients and ineffective in others. As a result, this study aimed to test whether the normalization of heart function effectively abolished CSA.

The materials and methods applied in this study included patients selected for heart transplantation assessment at a university hospital. A computerized system (polysomnography) monitored and determined signs of respiratory discomfort during sleep among the sampled patients. In addition, urine volume and renal function were also examined from overnight urinary norepinephrine excretion (UNE).

Results showed that 13 patients with severe CHF and who underwent a heart transplant were included in this analysis, and the control group consisted of 9 patients. Moreover, there was a significant reduction in CSA symptoms after transplantation, marked by a shortened cycle length (about 65 to 31 units). The apnea-hypopnea index (AHI) and UNE also dropped significantly due to normalized left ventricular ejection fraction (LVEF). Out of the CSA group that underwent a heart transplant, seven had no sleep-disordered breathing (SDB), three had severe CSA, and four acquired obstructive sleep apnea (OSA). However, none in the control group had CSA or OSA.

In conclusion, Mansfield et al. showed that CSA symptoms might persist even after a successful heart transplant and a normalized sympathetic nerve activity. They also recommend further studies to enhance the understanding of sleep disordered breathing (SDB).

Reference

Mansfield DR, Solin P, Roebuck T, Bergin P, Kaye DM, Naughton MT. The effect of successful heart transplant treatment of heart failure on central sleep apnea. Chest. 2003 Nov 1;124(5):1675-81.