• O A Smiseth, C R Thompson, K Lohavanichbutr, H Ling, J G Abel, R T Miyagishima, S V Lichtenstein, and J Bowering.
• St. Paul's Hospital, Vancouver, British Columbia, Canada. o.a.smiseth@rh.uio.no
• J. Am. Coll. Cardiol. 1999 Sep 1; 34 (3): 802-9.

ObjectivesThe purpose of this study was to determine the origin of the pulmonary venous systolic flow pulse using wave-intensity analysis to separate forward- and backward-going waves.BackgroundThe mechanism of the pulmonary venous systolic flow pulse is unclear and could be a "suction effect" due to a fall in atrial pressure (backward-going wave) or a "pushing effect" due to forward-propagation of right ventricular (RV) pressure (forward-going wave).MethodsIn eight patients during coronary surgery, pulmonary venous flow (flow probe), velocity (microsensor) and pressure (micromanometer) were recorded. We calculated wave intensity (dP x dU) as change in pulmonary venous pressure (dP) times change in velocity (dU) at 5 ms intervals. When dP x dU > 0 there is a net forward-going wave and when dP x dU < 0 there is a net backward-going wave.ResultsSystolic pulmonary venous flow was biphasic. When flow accelerated in early systole (S1), pulmonary venous pressure was falling, and, therefore, dP x dU was negative, -0.6 +/- 0.2 (x +/- SE) W/m2, indicating a net backward-going wave. When flow accelerated in late systole (S2), pressure was rising, and, therefore, dP x dU was positive, 0.3 +/- 0.1 W/m2, indicating a net forward-going wave.ConclusionsPulmonary venous flow acceleration in S1 was attributed to a net backward-going wave secondary to a fall in atrial pressure. However, flow acceleration in S2 was attributed to a net forward-going wave, consistent with propagation of the RV systolic pressure pulse across the lungs. Pulmonary vein systolic flow pattern, therefore, appears to be determined by right- as well as left-sided cardiac events.

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