Pulmonary Venous Flow in Normal Dogs Recorded by Transthoracic Echocardiography: Techniques, Anatomic Validations and Flow Characteristics

Abstract

To observe pulmonary venous flow in dogs, the echocardiographic imaging planes and the techniques for examination, and the validations of anatomic location were investigated. Then, the velocity pattern of pulmonary venous flow was recorded in normal conscious dogs. Six imaging planes were available for observing the right or left caudal lobe pulmonary venous flow with two-dimensional or pulsed Doppler echocardiography. Of these, the left lateral apical 4-chamber view can be applied as standard view, because the pulmonary venous flow and transmitral flow could be recorded in this view simultaneously with small sampling angle. The velocity pattern of pulmonary venous flow demonstrated two forward waves in 19 of 20 dogs examined, with one peak occurring during ventricular systole and another during ventricular diastole. A reversed flow during atrial contraction was also seen in 11 dogs. In the two forward waves, the mean peak velocity and velocity-time integral of ventricular diastolic forward flow were significantly higher than those of systolic forward flow (46.49 ± 6.79 vs. 31.13 ± 4.92 cm/s, p<0.0001 and 8.18 ± 1.84 vs. 5.14 ± 0.82 cm, p<0.0001, respectively). The deceleration time of diastolic forward flow shortened with the increase of heart rate (r=^-0.87, p<0.0001). Pulmonary venous flow in dogs can be observed under transthoracic two-dimensional or pulsed Doppler echocardiography.