Aim: Limited data are available about the use of Doppler myocardial imaging (DMI) in small animals. We intend to provide reference values for velocity, strain and strain rate in a large group of healthy rats and studied the reproducibility and repeatability of these parameters.
Methods and results: A total of 33 male Wistar rats (503+/-41g) underwent baseline transthoracic echocardiography with DMI of the anterior and inferior wall in a short-axis view using a 13MHz linear probe. Adequate tissue Doppler measurements could be obtained in 30 rats. On average 10+/-4 consecutive cycles were studied in post-processing using dedicated software (SPEQLE). Mean radial peak systolic velocity, strain and strain rate were respectively -0.8+/-0.3cm/s, 38+/-8% and 9.1+/-2.0/s in the anterior wall and 3.1+/-0.6cm/s, 49+/-10% and 13.7+/-3.7/s in the inferior wall. The reproducibility and repeatability of the DMI measurements assessed in 10 rats was good.
Conclusion: DMI is feasible and reproducible in healthy rats. Establishing reference values opens new perspectives towards the use of strain and strain rate imaging in small rodents in the assessment of myocardial diseases.