High frame rate Doppler echocardiography in the rat: an evaluation of the method.
OBJECTIVE
In small animal models, two-dimensional (2D) and Doppler echocardiography should provide more information than M-mode, especially in animals with infarcted and distorted left ventricles, but has been limited by low frame rates and poor near field resolution. New, high frame rate echo-Doppler equipment with digital processing was tested for accuracy of measurements.


RESULTS
Fourteen normal Wistar rats (232-328 g) were examined under halothane anaesthesia. Pulsed Doppler recordings from both left ventricular outflow tract(LVOT) and right ventricular outflow tract (RVOT) cor-responded well with simultaneous ultrasound transit time measurements of aortic flow (LVOT: v=0.99x+4.8, min R=0.93. Standard error of estimate (SEE)=8.3 ml x min(-1), and RVOT: v=0.97x -4.3. R=0.93. SEE =8.4 ml x min(-1). No systematic differences were observed over a flow range of 20-90 ml x min(-1). Left ventricular (LV) dimensions assessed by 2D parasternal long-axis and short-axis views were equal to M-mode measurements with LV diameter 6.6 + 0.44 mm, anterior wall 1.8 +/- 0.18 mm, and posterior wall 1.5 + 0.56 mm. Mean absolute difference 4.4-8.5%. Intra- and interobserver variability was 4.6 +/- 4.1% and 6.7 +/- 7.0% for Doppler measurements, and 4.3 +/- 3.8% and 3.8 +/- 4.6% for dimensions, respectively.


CONCLUSIONS
High frame rate Doppler echocardiography provides accurate non-invasive measurements of cardiac structure and function in the rat.
Bjornerheim
R
R
Department of Cardiology, Rikshospitalet, University of Oslo, Norway.
Grogaard
H K
HK
Kjekshus
H
H
Attramadal
H
H
Smiseth
O A
OA
D000818:Animals; D001021:Aortic Valve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D002302:Cardiac Output / Q000502:physiology; D003971:Diastole / Q000502:physiology; D015150:Echocardiography, Doppler / Q000379:methods / Q000592:standards; D006339:Heart Rate / Q000502:physiology; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008297:Male; D008943:Mitral Valve / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D023421:Models, Animal; D008955:Models, Cardiovascular; D015588:Observer Variation; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D013599:Systole / Q000502:physiology; D013997:Time Factors