Last Updated: 2008-07-16 15:07:04 -0400 (Reuters Health)

Nasal continuous positive airway pressure (nCPAP) improves global left ventricular performance and decreases brain natriuretic peptide (BNP) levels in men with obstructive sleep apnea syndrome, Japanese researchers report in the June 15 issue of the American Journal of Cardiology.

Effects can be seen within 1 month of the initiation of nCPAP, they found.

Dr. Satoshi Ikeda and colleagues at Nagasaki University School of Medicine measured the myocardial performance index (Tei index) on echocardiography, as well as BNP concentrations, in 27 male patients with obstructive sleep apnea syndrome and 22 age-matched men who served as controls.

The patients had a mean apnea-hypopnea index of 42.2 events per hour and were started on nCPAP.

Global left ventricular dysfunction was defined as a Tei index of 0.50 or greater, and a high BNP as 20 pg/mL or higher.

At baseline, the mean Tei index was significantly higher in patients than controls, at 0.43 and 0.35, respectively. There was a roughly linear increase in apnea-hypopnea index with increases in Tei index in the study group.

The prevalence of global left ventricular dysfunction was 19% in the study group and absent in controls.

BNP levels were high in 37% of sleep apnea patients at baseline compared with 9% of controls, a difference that did not reach statistical significance, the investigators note.

BNP decreased significantly after 3 months of nCPAP therapy. The Tei index decreased significantly within 1 month of nCPAP therapy and it decreased further after 3 months of nCPAP therapy.

The prevalence of global left ventricular dysfunction decreased significantly with nCPAP, from 19% at baseline to 4% after 3 months of therapy.

Summing up, the team concludes: "Patients with moderate to severe obstructive sleep apnea syndrome frequently have impaired global left ventricular myocardial performance, which can be reversed at the early stage after starting nCPAP."

Am J Cardiol 2008;101:1796-1800.