Aims: The purpose of our study was to evaluate the usefulness of the isovolumetric relaxation time in both ventricles when diagnosing acute rejection in transplanted patients.
Method: 68 endomyocardial biopsies were performed on a total of 38 patients. An echocardiographic study was carried out within the first 24 hours of each biopsy. All registrations were made by the same person. The isovolumetric relaxation time was measured in the left and right ventricles. The patients were divided according to two criteria: according to the degree of rejection (0-I, II, III) and according to whether the rejection was treatable (III) or non-treatable (0, I and II).
Results: In both ventricles, there was a progressive decrease of the isovolumetric relaxation time corresponding to higher degrees of rejection: in the left ventricle (0-I = 90 +/- 16; II = 74 +/- 16; III = 70 +/- 26; significant differences of II and III in relation to 0-I) as well as in right ventricle (0-I = 43 +/- 16; II = 37 +/- 14; III = 29 +/- 8; significant difference of III in relation to 0-I). The patients with treatable and non-treatable rejection were compared: no differences were found in the isovolumetric relaxation time of the left ventricle (0, I and II = 85 +/- 16 vs III = 70 +/- 26), but they were found in the right ventricle (0, I and II = 41 +/- 15 vs III = 29 +/- 8).
Conclusions: Acute heart rejection induces a decrease of the isovolumetric relaxation time in both the left ventricle and the right ventricle. However, the isovolumetric relaxation time of the right ventricle seems to be a more useful parameter than isovolumetric relaxation time of the left ventricle, as it permits to detect whether an acute heart rejection is treatable or non-treatable.