Automated versus observer blood pressure as determinants of left ventricular structure

We studied the contribution of automated blood pressure measurements to the variation in left ventricular structural characteristics, independent of pressure measured by an observer. Thirty eight patients referred for hypertension underwent 24 h blood pressure monitoring. Echocardiography and repeated blood pressure measurements were taken on 2 different days by an observer and by the use of the Dinamap 845 device. Blood pressure by the observer averaged 157/101 mmHg, Dinamap pressure 152/94 mmHg, 24 h pressure 137/92 mmHg, left ventricular mass 218 g and mean wall thickness 12.7 mm. Left ventricular mass and wall thickness were related (P < 0.05) to systolic observer (r = +0.46; r = +0.47), Dinamap (r = +0.42; r = +0.41) and 24 h blood pressure (r = +0.46; r = +0.53); the correlation coefficients were lower (r = +0.35 to +0.51; P < 0.05) for diastolic pressure. These relations were independent of age, gender, height, weight and heart rate. The Dinamap pressure did not contribute to the difference in the left ventricular structural characteristics, independent of the observer pressure. The 24 h ambulatory pressure explained a small but significant (P < 0.05) fraction of the variation in mean wall thickness in addition to the observer pressure. Left ventricular mass and mean wall thickness were not related to the day-night difference in blood pressure (P > 0.25). In conclusion, observer, Dinamap and ambulatory pressures are significantly related to cardiac structural variables. Ambulatory pressure, but not Dinamap pressure, explains a small part of wall thickness variance in addition to well-standardized pressure measured by an observer.