Background: Obstructive sleep apnoea (OSA) has the potential to cause heart failure. We aimed to determine the effects of nasal continuous positive airway pressure (CPAP) therapy on left ventricular structure and myocardial performance index (MPI) in severe OSA patients.
Methods: Sixty-seven subjects without any cardiac or pulmonary disease had overnight polysomnography and echocardiography. In 33 males with severe OSA, thickness of interventricular septum (IVS) and posterior wall (LVPW) were measured by M-mode. Left ventricular MPI was calculated as (isovolumic contraction time+isovolumic relaxation time)/aortic ejection time by Doppler.
Results: Eight males were non-compliant with CPAP. Mean age was 47.9+/-8.2 years, and 20 of 25 patients (80.0%) were hypertensive. Patients had high body mass index (BMI: 31.0+/-3.9 kg/m(2)), but there was no change in BMI from baseline after 6 months. Thickness of IVS (11.0+/-1.1mm) and LVPW (11.0+/-1.0mm) at baseline were significantly decreased after 6 months of CPAP therapy (10.5+/-0.9 mm, P<0.001 and 10.4+/-0.7 mm, P<0.0001, respectively). Left ventricular MPI (60.1+/-13.8%) significantly decreased (53.0+/-10.7%, P<0.0001) after CPAP usage.
Conclusions: In male patients with severe OSA, CPAP therapy significantly decreases left ventricular wall thickness and improves global function even with 6 months of usage.