Pulmonary vein flow pattern in man during thoracotomy.

Pulmonary vein flow (PVF) pattern was traced with an electromagnetic flowmeter in 10 patients with normal hearts undergoing operations for pulmonary diseases. Instantaneous pulmonary artery flow, ECG, pulmonary artery pressure and left atrial pressure were recorded simultaneously. The pulsatile flow patterns obtained ocrresponded well to those previously found in dogs, and were remarkably similar to caval flow pattern. A constant and inverse relationship between the contour of the right atrial pressure andthe PVF pattern was found. In 3 patients, PVF was reversed by atrial systole; otherwise the flow was forward throughout the cardiac cycle. The influence of positive pressure ventilation was small, consisting of a slight initial inspiratory increase followed by a decrease during the latter half of inspiration.