Left-to-right systolic and diastolic ventricular interactions are dependent on right ventricular volume.
Three-compartment elastance modeling predicts that the magnitude of gain is solely dependent on the ratio of free wall and septal elastances. However, when nonlinearities in pressure-volume relationships are considered, the same model predicts that gain is load dependent. We therefore studied left-to-right ventricular interactions in the isolated cross-perfused canine heart preparation to determine whether, in fact, right ventricular volume modulates left-to-right ventricular interaction. We found that left-to-right systolic gain increased from 0.035 +/- 0.022 to 0.073 +/- 0.017 (P = 0.003) and left-to-right diastolic gain increased from 0.067 +/- 0.050 to 0.186 +/- 0.097 (P = 0.03) in response to increased right ventricular volume. This degree of volume dependency of gain is predicted by the three-compartment model when measured nonlinearities in time-varying elastance are taken into account. Future studies will need to account for changes in loading conditions when interpreting changes in systolic and diastolic interactions.
Dickstein
M L
ML
Department of Anesthesiology, Columbia University, New York, New York 10032, USA.
Todaka
K
K
Burkhoff
D
D
D000818:Animals; D001794:Blood Pressure; D001810:Blood Volume; D003971:Diastole; D004285:Dogs; D008955:Models, Cardiovascular; D013318:Stroke Volume; D013599:Systole; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right