Exercise tissue Doppler echocardiography with strain rate imaging in healthy young individuals: feasibility, normal values and reproducibility.
ABSTRACT The study was done to determine the clinical feasibility and reproducibility of tissue Doppler echocardiography (TDE) with strain rate imaging (SRI) at rest and under physical exercise in healthy young individuals and to report normal values for parameters of regional myocardial function under exercise.
Forty-five young volunteers (age 9-29 years) underwent echocardiography with TDE/SRI at rest and during a bicycle exercise test (2 W/kg body weight).
Velocities could be obtained in 93% of segments, whereas strain rate was measurable at least in 80% of segments. Inter- and intraobserver variability for measurement of velocities under exercise was 14% and 9%, respectively for strain rate 28% and 20%. Except for peak strain, values for all other parameters were higher during exercise with the clearest response in the left lateral and the right ventricular wall.
(1) Tissue Doppler with strain rate imaging is a practical and robust method for assessment of regional function of both ventricles under exercise. (2) Systolic motion, local myocardial relaxation and contractility increased significantly under physical exercise. These normal values obtained from healthy young subjects can serve as a reference database for further clinical studies.