Pulmonary artery velocity patterns in ductus arteriosus

SUMMARY In 12 patients with ductus arteriosus a characteristic velocity pattern in the pulmonary artery was identified using pulsed Doppler echocardiography. This pattern, which was absent in 52 normal control subjects and 200 consecutive patients with cardiac lesions other than ductus, con-sisted of a pandiastolic velocity directed away from the transducer. This pattern is thought to represent the diastolic component of flow into the pulmonary tree which occurs as a result of the left to right shunt. Pulmonary artery velocity patterns, determined by Doppler echocardiography and analysed by time interval histography, have previously been reported for patients with ductus arteriosus.'-3 Doppler examination of a patient with ductus arteriosus is per-formed by imaging the main and branch pulmonary arteries from a left parasternal short axis position. Previous reports suggest that with the sample volume placed into the main pulmonary artery just proximal to the bifurcation the usual systolic velocity pattern is of flow directed away from the transducer (which we subsequently refer to as negative velocity). This nega-tive velocity is said to be followed by disturbed flow generally directed toward the transducer (which we refer to as positively directed velocity). This diastolic pattern probably represents detection of the ductal jet. The disturbed feature, as registered by time inter-val histography, could be due to either alinear spectral analysis or detection of disturbed flow. One previous report2 mentions the presence of diastolic negatively directed velocity in the pulmonary artery, but the accepted Doppler criterion for the presence of a duc-tus arteriosus remains the demonstration of positively directed pulmonary artery velocity.3 In this report we describe a velocity pattern which we found in patients with ductus arteriosus and which is different from the commonly accepted pattern