Immediate and short-term effects of pulmonary artery banding on left ventricular performance in foetal sheep.
OBJECTIVE
To evaluate foetal left ventricular performance when its preload was increased by banding the pulmonary artery, a study design where a simultaneous change in left ventricular afterload is unlikely.


METHODS
Nine ovine foetuses were studied with real-time images and Doppler echocardiography before, 3-4 and 6-8 d after surgery. Seven of these foetuses were also studied during the surgical intervention, immediately before and within 2 min after banding.


RESULTS
The immediate effects of a 90-95% reduction of the pulmonary artery cross-sectional area were: a 53 +/- 20% (mean +/- SD) decrease and a 38 +/- 10% increase of right (RvQ) and left ventricular output (LvQ), respectively. Comparing measurements before and 3-4 d after operation, there was a 64 +/- 16% decrease of RvQ and a 64 +/- 25% increase of LvQ. The increase in LvQ was due to an increase in both heart rate (19 +/- 10%) and stroke volume (38 +/- 18%). After an additional 3-4 postoperative days, heart rate remained increased to the same extent, but there was a more pronounced increase of LvQ (93 +/- 19%) and stroke volume (59 +/- 22%).


CONCLUSIONS
The parallel foetal circulation has a capacity to handle a severely increased afterload for the right ventricle by immediately improving and maintaining an increased left ventricular performance. This improvement was in part accomplished by an increase in stroke volume.
Sonesson
S E
SE
Foetal Cardiology Unit, Paediatric Cardiology Service, Department of Paediatrics, St. Justine Hospital. University of Montreal, Montreal, Quebec, Canada.
Fouron
J C
JC
Teyssier
G
G
Skoll
A
A
Chartrand
C
C
D000704:Analysis of Variance; D000818:Animals; D015150:Echocardiography, Doppler; D005318:Fetal Heart / Q000000981:diagnostic imaging / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D011184:Postoperative Period; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000601:surgery*; D012756:Sheep; D013318:Stroke Volume / Q000502:physiology; D013997:Time Factors; D014656:Vascular Surgical Procedures / Q000379:methods*; D016277:Ventricular Function, Left / Q000502:physiology*