THE PRESSURE WAVE FORM IN THE PULMONARY ARTERY

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Abstract
The pulmonary artery wave form during diastole has been studied in 43 patients using a catheter-tip micromanometer. A small presystolic wave was seen in 30 patients, and from its timing it seems likely that it reflected contraction of the right atrium. A clear dicrotic wave was present in 35 of the subjects. It was large in patients with an increased pulmonary blood flow due to an atrial or ventricular septal defect, and small or absent in patients with pulmonary hypertension or pulmonary stenosis. A small secondary pressure wave was seen to follow the dicrotic wave in 18 patients. These extra waves were only seen in patients who had large dicrotic waves, and both they and the dicrotic waves tended to be smaller in pressure tracings obtained from the branches of the pulmonary artery. The findings imply that the dicrotic and secondary waves have a common origin in the main pulmonary trunk, and possible mechanisms for their production are discussed. In the presence of a normal pulmonary valve, the size of the dicrotic wave and the presence or absence of secondary pressure waves depend upon the hemodynamic characteristics of the pulmonary vascular system.