Aims: The aim of the study was to characterize left ventricular (LV) function by Doppler tissue imaging (DTI) after a first myocardial infarction (MI) where the conventional echo-Doppler parameters showed no abnormalities.
Methods: Out of 202 patients who were referred for an echocardiogram, 19 patients were previously healthy and had a normal ejection fraction and no wall motion abnormalities at echocardiogram. These 19 patients were compared with 16 age-matched healthy subjects (HS). The longitudinal LV function was assessed using the mitral annular velocities (mean value from four different sites of the LV) determined by DTI.
Results: The patients with MI had significantly reduced peak systolic and peak early diastolic mitral annular velocities compared to HS (8.6 v. 9.7 cm/s, P<0.001 for systolic velocity, and 10.9 v. 12.3 cm/s, P<0.01 for diastolic velocity, respectively). The patients had normal diastolic LV function assessed by the conventional Doppler echocardiogram (e.g. transmitral flow, IVRT and pulmonary venous flow patterns). To assess the LV filling pressure, the ratio of the transmitral early wave velocity assessed by conventional echo-Doppler and peak early diastolic mitral annular velocity determined by DTI (E/Edti) was used. The E/Edti was significantly higher in patients than in HS (7.0 v. 5.7, P<0.05).
Conclusion: Previously healthy subjects who are suffering from a first MI and showing normal systolic and diastolic LV function, determined by conventional echo-Doppler methods, show decreased mitral annular systolic and diastolic velocities determined by DTI compared to healthy subjects. This is probably evidence of mild subendocardial damage due to MI that remains undetected by conventional echo-Doppler methods.