Ventricular hypertrophy in sleep apnoea.
Ventricular hypertrophy is associated with an increased risk of cardiovascular death and cardiac events. In response to a haemodynamic load, ventricular hypertrophy may either be eccentric (dilation in response to volume overload) or concentric (increase in wall thickness in response to pressure overload). Ventricular hypertrophy increases with age, weight, blood pressure, and the presence of cardiovascular disease. It is greater in men than in women when adjusting for other variables. Echocardiography is the best method for accurate quantification of left ventricular mass and for detecting right ventricular hypertrophy. In obstructive sleep apnoea there are reports of both eccentric and concentric hypertrophy of the left ventricle. However, many of these reports have failed to control for patient weight or age. More recent reports indicate that much of the hypertrophy of the left ventricle reported in obstructive sleep apnoea can be related to patients' age, blood pressure, or size. However, right ventricular hypertrophy appears to be distinctly associated with the presence and severity of obstructive sleep apnoea. Right ventricular hypertrophy secondary to obstructive sleep apnoea may be the substrate for the eventual development of cor pulmonale and right heart failure. Its pathophysiological significance and potential use as a marker of severe OSA requires further investigation. Further investigation into left ventricular hypertrophy and sleep apnoea must control for the potentially confounding variables listed above and will require population-based and/or carefully matched case control studies.
Davidson
WR
Cardiology Division, The Pennsylvania State University College of Medicine, Hershey, USA.