Nocturnal blood pressure predicts left ventricular mass index in normotensive elderly

Blood pressure (BP) predictors of left ventricular mass index (LVMI) were studied in 40 healthy normotensive (71.4 +/- 4.4 years) and 31 hypertensive (73.5 +/- 4.8 years) elderly community-dwelling subjects using short-axis cardiac cine magnetic resonance imaging and 24-h ambulatory BP monitoring. Mean night-time BPs were calculated from the average of readings during sleep and mean daytime BPs were calculated from the remaining recordings. The hypertensive subjects were all receiving anti-hypertensive therapy with angiotensin-converting enzyme (ACE) inhibitors, calcium-channel blockers, beta-blockers or diuretics. Nocturnal systolic BP was a strong predictor of LVMI in both normotensive (beta = 0.38, p = 0.02) and treated hypertensive (beta = 0.39, p = 0.03) subjects. By contrast, daytime systolic BP was a weaker predictor of LVMI in the treated hypertensives (beta = 0.36, p = 0.04) and did not predict LVMI in the normal subjects (beta = 0.27, NS). Nocturnal BP may partly explain the increase in LVMI with ageing in subjects thought to be normotensive on the basis of daytime clinic BP recordings.