Diastolic function is involved early during the undetermined form of Chagas' disease (Ch). Pulsed Doppler tissue imaging (DTI) is a new technique to evaluate diastolic function recording myocardial velocities in the longitudinal axis. To evaluate the relevance of DTI in patients with Ch, we studied, with Doppler and echocardiography, 49 patients (average age 49 +/- 12 years) and 20 normal subjects (average age 45 +/- 15 years) as a control group (C). Patients were divided in four groups according to the pattern of their mitral and pulmonary vein flows: Normal diastolic function (N), prolonged relaxation (PR), pseudonormal (PN) and restrictive (R). Peak velocity of the E wave of the lateral mitral annulus (Ea) was diminished in PR, PN, and R patients (0.11 +/- 0.02 m/s, 0.10 +/- 0.02 m/s and 0.12 +/- 0.06 m/s, respectively) as compared to group C (0.18 +/- 0.07 m/s, p < 0.01) but not with respect to group N (0.15 +/- 0.03 m/s, N.S.). In this latter group only peak E velocity of transmitral flow/Ea ratio was useful to detect diastolic abnormalities as compared to group C (4.92 +/- 0.98 vs 4.14 +/- 1.26, p < 0.05). DTI was useful in the assessment of diastolic function in Ch, including those patients in whom mitral and pulmonary vein flows were normal.