Severe obstructive sleep apnea elicits concentric left ventricular geometry.

BACKGROUND: Obstructive sleep apnea (OSA) has several negative effects on the heart including increase in myocardial end-systolic stress, venous return and sympathetic activity, all potential stimuli of left ventricular (LV) hypertrophy. The impact of the severity of OSA on LV geometry is unknown. We hypothesized that OSA is related to concentric LV geometry.
METHODS: One hundred and fifty-seven patients with suspected OSA underwent echocardiography, ambulatory 24-h blood pressure and ECG monitoring. On the basis of the severity of OSA, patients were divided into controls, mild OSA and moderate/severe OSA (apnea-hypopnea index <5, 5-15 and >15/h, respectively). Patients with LV hypertrophy were defined as LV mass at least 49.2 g/m2.7 for men and at least 46.7 for women. Relative wall thickness of at least 0.43 identified patients with concentric LV geometry.
RESULTS: Patients with moderate/severe OSA (n = 86) had a higher body mass index and a higher prevalence of paroxysmal atrial fibrillation than those (n = 51) with mild OSA and controls (n = 20). Prevalence of hypertension, diabetes, obesity, LV mass and blood pressure did not differ between the groups. Relative wall thickness was positively related to apnea-hypopnea index (r = 0.30; P = 0.003) and the prevalence of concentric LV geometry was 20% in controls, 12% in mild OSA and 58% in moderate/severe OSA (P < 0.001). In logistic regression analysis concentric LV geometry was associated with moderate/severe OSA [odds ratio (OR) 7.6, P < 0.001], low stress-corrected midwall shortening (OR 3.38, P = 0.004), and higher body mass index (OR 1.09, P = 0.03).
CONCLUSIONS: Moderate/severe OSA is associated with high prevalence of concentric LV geometry. This increased prevalence may in part explain the increased rate of cardiovascular events in these patients.