It is recently shown that the majority of acromegalic patients without concomitant heart disease have diastolic dysfunction at rest. The aim of this study is to evaluate left ventricular diastolic function in normotensive acromegalic patients without any evidence of heart disease. Eleven acromegalic patients and 16 normal subjects of comparable age and sex distribution were studied by echocardiography. Left ventricular end-diastolic diameter, interventricular septal thickness, left ventricular posterior wall thickness, left ventricular end-diastolic volume and stroke volume were found to be significantly higher in acromegalic patients. Left ventricular mass and left ventricular mass index increased significantly in acromegalics in comparison with controls (229.16+/-46.41 g versus 167.17+/-24.57 g and 124.99+/-26.91 g/m(2) versus 95.09+/-13.29 g/m(2) respectively, p<0.001). Mitral A wave desceleration rate and isovolumetric relaxation time (IVRT) -two of the studied parameters of left ventricular diastolic filling-were significantly prolonged in patients as compared with controls (p-0.03 and p<0.001 respectively), Four (36%) of the acromegalic patients had peak early/late diastolic mitral velocity ratio lower than 1, indicating diastolic dysfunction. All of the patients had IVRT longer than 90 ms (mean + 2 standart deviations of normals). It is concluded that in acromegalic patients without any other evidence of heart disease left ventricular diastolic function is impaired. This indicates a specific cardiomyopathy exists in the subclinical stage. IVRT is found to De more sensitive than other studied parameters for detecting diastolic dysfunction at this stage. (C) 1997, Editrice Kurtis.