Atrioventricular plane displacement (AVPD) study by M-mode echocardiography can supply useful clinical information about left ventricular (LV) long-axis function. We assessed the hypothesis that AVPD estimation could be used to detect early hypertensive cardiomyopathy. The study population included 81 hypertensive patients with normal LV ejection fraction and fractional shortening, and 50 age- and gender-matched healthy controls. By utilizing M-mode and apical views, the following parameters were estimated: early mitral flow peak velocity (E) and deceleration time (DT), peak velocity of late mitral flow (A), A/E ratio, isovolumic relaxation time (IVRT), total AVPD, AVPD motion during atrial systole (At), systolic AVPD (total AVPD-At), and At/total AVPD ratio. Of 81 hypertensive patients, 16 (19.7%) had a normal (Group 1) and 65 (80.3%) an impaired LV relaxation filling pattern (Group 2). Mean total AVPD-At was significantly lower in Group 2 than in Group 1 (7.1 +/- 2 vs. 10.3 +/- 3 mm, p<0.001) and in Group 1 compared with healthy subjects (10.3 +/- 3 vs. 13.1 +/- 1 mm, p<0.001). Mean At and At/total AVPD were significantly higher in Group 2 than in Group 1 (46.9 +/- 8.6 vs. 37.7 +/- 8.7%, p<0.001), but not in Group 1 compared with healthy subjects (37.7 +/- 8.7 vs. 36 +/- 6%, p>0.05). Hypertensive patients without overt systolic dysfunction demonstrate LV long-axis systolic dysfunction, while long-axis diastolic dysfunction always coexists with abnormal diastolic filling patterns. This suggests that long-axis systolic dysfunction precedes diastolic dysfunction at the same axis in hypertensive patients.