OBJECTIVE The purpose of this study was to examine the relation of the central arterial pressure waveform to left ventricular and carotid structure. BACKGROUND The pressure waveform in the central arteries is affected by reflection of the pressure wave from the periphery. When reflected waves merge with the incident wave during systole, a late systolic peak and increment in systolic blood pressure are observed. The consequent increase in hemodynamic load may stimulate left ventricular and vascular adaptive changes. METHODS Sixty-seven normotensive adults were studied by noninvasive techniques. Anatomy and function of the left ventricle and carotid artery were investigated by ultrasonography. Pressure waveforms were recorded by an external tonometer applied to the carotid artery, and waveform shape was expressed by the augmentation index, calculated from the difference between the maximal systolic pressure and that at the inflection between early and late systolic pressure peaks divided by the pulse pressure. Subjects were assigned to groups with a dominant early (group 1, augmentation index < or = 0) or dominant late systolic peak (group 2, augmentation index > 0). RESULTS Left ventricular mass index was significantly higher in group 2 than in group 1, a difference that persisted after controlling for the confounding effects of gender, age and blood pressure. Carotid wall thickness and regional arterial stiffness were significantly increased in group 2, but differences disappeared in the analysis of covariance for age. CONCLUSIONS Left ventricular and carotid artery structure are related to the shape of the central pressure waveform. Although the increase in left ventricular mass seen in subjects with a dominant late systolic peak pressure appears to be directly related to the shape of the pressure waveform, changes in the structural and physical properties of the carotid artery appear to be more closely related to the aging process.