Coexistence of obstructive sleep apnoea and metabolic syndrome is independently associated with left ventricular hypertrophy and diastolic dysfunction.

Purpose: This study was conducted to investigate the impact of the severity of obstructive sleep apnoea (OSA) and metabolic syndrome (MS) on left ventricular (LV) hypertrophy and LV diastolic function.

Methods: Echocardiography for evaluation of LV hypertrophy (defined by relative wall thickness (RWT) and LV mass index (LVMI)) and for diastolic function (defined by the early rapid/atrial filling velocity (E/A ratio)) was performed on 660 OSA patients.

Results: In patients with both MS and severe OSA, LVMI and RWT were significantly higher and the E/A ratios were significantly lower compared to patients with neither MS nor severe OSA. Multivariate analysis after adjustment for other descriptive variables demonstrated that (1) coexistent MS and severe OSA was independently associated with increased LVMI and RWT and (2) severe OSA, MS and coexistence of both disorders were independently associated with a decreased E/A ratio. Significant interaction between MS and severe OSA was not observed with respect to LVMI and RWT, but was observed for the E/A ratio.

Conclusions: Coexistent severe OSA and MS can exacerbate LV concentric hypertrophy. However, not only the coexistence of these two disorders, but also either severe OSA or MS can impair LV diastolic function.