The changes of left ventricular (LV) diastolic function associated with cardiac rejection were evaluated. Twenty-one cardiac allograft recipients aged 41 +/- 9 years, 11 with moderate to severe and 10 allograft rejection without rejection at myocardial biopsy underwent serial echo examination, including peak velocity (PEV), pressure half-time (PHT), velocity-time integral (VTI-E) of early mitral flow, and isovolumetric relaxation period (IVRP). In transplant recipients, significantly higher values than in 22 age-matched healthy controls were found for PEV (71 versus 56 cm/s; P less than 0.01), PHT (51 versus 43 ms; P less than 0.001), VTI-E (72 versus 57 mm; P less than 0.001), and IVRP (90 versus 73 ms; P less than 0.001). During rejection, heart rate increased significantly from 78 to 91 beats per minute (P less than 0.01). Furthermore, a significant decrease was found for PEV from 73 to 63 cm/s (P less than 0.01), for PHT from 52 to 40 ms (P less than 0.001), for VTI-E from 75 to 61 mm (P less than 0.001), and for IVRP from 90 to 74 ms (P less than 0.001) during cardiac rejection. Thus, sonographic evaluation of LV diastolic function helps to early detect cardiac rejection and to decrease the frequency of myocardial biopsy.