Mid-diastolic opening of the pulmonary valve after right ventricular infarction.

Premature opening of the pulmonary valve in mid-diastole before atrial systole was observed during inspiration in a patient with extensive right ventricular infarction. Transient inspiratory elevation of right ventricular diastolic pressure to a level exceeding pulmonary artery pressure was documented. Although forward flow into the pulmonary artery was seen on Doppler echocardiography after atrial systole, most of the flow continued to be in response to right ventricular contraction, despite extensive infarction.