In a population of 43 primary hypertensive patients we investigated the mitral and tricuspid valve flow in order to test whether: a) hypertension, as compared to normotension (Group 0, 10 normotensive subjects), alters the ventricular filling; b) changes are shared by the left and the right side of the heart; c) the structural characteristics (ultrasounds) of the left ventricle (LV) correlate with these changes. Hypertensives were divided into: Group 1, 11 patients in whom thickness (th) of both the ventricular septum (VS) and LV posterior wall (PW) was within a normal range (mean +/- 1 SD of values derived from 145 normal subjects); Group 2, 8 patients whose VSth exceeded normal values by more than 1 SD; Group 3, 24 patients in whom both VSth and PWth exceeded normal values by more than 1 SD. Groups 0, 1, 2 and 3 were homogeneous regarding gender, age, heart rate, LV cavity dimensions and systolic function. Blood pressure was slightly increased from Group 1 to Group 2 to Group 3. Mitral peak flow velocity in early diastole (PFVE) was similar in the 4 groups; in late diastole peak flow velocity (PFVA) through the same valve in each of the 3 hypertensive groups was significantly higher than in Group 0; as a consequence, PFVE/PFVA and E'/A' areas in hypertensives were significantly smaller than in normotensives. The flow pattern through the tricuspid valve was quite similar to this in each group.(ABSTRACT TRUNCATED AT 250 WORDS)