OBJECTIVE--To study possible disturbances in left ventricular long axis function in patients with a restrictive filling pattern. DESIGN--Prospective examination of the left ventricular transverse and longitudinal axes, transmitral flow, and the apexcardiogram. SETTING--A tertiary referral centre for cardiac diseases. SUBJECTS--21 normal subjects, age (SD) 51(11); 30 patients of similar age with a restrictive left ventricular filling pattern, defined as short early diastolic deceleration time less than the lower 95% confidence limit of the normal value (120 ms). 20 patients had a normal and 10 had an increased left ventricular end diastolic cavity size. RESULTS--Mitral Doppler echocardiography: E wave velocity was high only in patients with a normal cavity size. A wave velocity was greatly reduced in the two groups (P < 0.001) so that the E/A ratio was abnormally high. The relative A wave amplitude on the apexcardiogram was greatly increased in the two groups: 46(15)% (mean (SD)) and 54(4)% v 15(5)%. Minor axis: Fractional shortening was reduced from 30(10)% to 17(7)% in patients with normal cavity size and to 13(4.2)% in those with a dilated cavity (P < 0.001), as was the posterior wall thickening fraction from 100(30)% to 42(20)% and 50(25)% respectively (P < 0.001). Total systolic epicardial motion was normal and isovolumic relaxation time was short in the two groups. Long axis: Left ventricular abnormalities included reduced total amplitude of motion and its component during atrial systole (P < 0.001 for the two groups at both sites). Peak long axis shortening and lengthening were decreased at both left ventricular sites (P < 0.001). The time intervals from q wave of the electrocardiogram and A2 (aortic valve closure) to the onset of shortening and lengthening respectively were increased (both P < 0.001). Right ventricular long axis function was similarly affected but to a lesser extent. CONCLUSION--Left ventricular long axis function is consistently abnormal in patients with restrictive disease whether or not cavity size is increased. Not only are the extent and peak velocity of shortening reduced, but during diastole the peak early diastolic lengthening rate and amplitude during atrial systole are impaired. Early diastolic long axis motion is asynchronous with respect to transmitral flow and left ventricular minor axis. These effects will impair the overall left ventricular systolic and diastolic function independently of any decrease in passive cavity compliance. Unlike fibrosis, these long axis abnormalities are potentially amenable to treatment.