In order to explore the relations between left ventricularmass (LVM) and the pulsatile (pulse pressure) andsteady (mean pressure) components of the bloodpressure (BP) curve, 304 young and middle-agedessential hypertensive patients were studied by meansof 24-h ambulatory BP monitoring and echocardio-graphy. In the overall study population, both the BPcomponents showed significant correlations with LVM.These correlations were unevenly distributed in thesubgroups of subjects younger and in those older than50 years. While in this latter subgroup, in multivariateanalysis, both 24-h mean BP (24-MBP) (b¼0.27;P¼0.008) and 24-h pulse pressure (24-h PP) (b¼0.23;P¼0.02) were associated with LVM, in the subset ofyounger hypertensives only 24-h MBP (b¼0.21;P¼0.009) was related to LVM, independent of othercovariates. The relations observed between 24-h PP andLVM in the entire study population and in the patientsolder than 50 years lost statistical significance when theeffect of 24-h systolic blood pressure (24-h SBP) wastaken into account, in a multiple regression model inwhich 24-h MBP was replaced by 24-h SBP. Our findingsseem to suggest that the association of PP with LVM inmiddle-aged hypertensives may partially explain theincreased cardiovascular risk, documented in subjectswith high PP. However, this relation is not independent,but is mediated by SBP.Journal of Human Hypertension (2003) 17, 231–238.doi:10.1038/sj.jhh.1001542Keywords: pulse pressure; mean blood pressure; ambulatory blood pressure; left ventricular mass