The pulmonary venous systolic flow pulse--its origin and relationship to left atrial pressure.
OBJECTIVE
The 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.


BACKGROUND
The 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).


METHODS
In 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.


RESULTS
Systolic 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.


CONCLUSIONS
Pulmonary 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.
Smiseth
O A
OA
St. Paul's Hospital, Vancouver, British Columbia, Canada. o.a.smiseth@rh.uio.no
Thompson
C R
CR
Lohavanichbutr
K
K
Ling
H
H
Abel
J G
JG
Miyagishima
R T
RT
Lichtenstein
S V
SV
Bowering
J
J
D000368:Aged; D016279:Atrial Function, Left / Q000502:physiology*; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods / Q000706:statistics & numerical data; D011667:Pulmonary Veins / Q000502:physiology*; D011673:Pulsatile Flow / Q000502:physiology*; D012044:Regression Analysis; D013599:Systole / Q000502:physiology