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Figure 10 Wall Stress–Volume Diagram in Severe Mitral Regurgitation With Depressed Ventricular Function

Chronic volume overload shifts the wall stress–volume relation to the right, and severe myocardial depression displaces it further to the right and reduces its slope. Pre-operatively, the ejection fraction (EFx) is only slightly reduced (50%) because of the large leak into the left atrium. If the mitral valve is replaced in this setting, the EFx can decrease sharply (37%) because the weakened left ventricle must now eject entirely into the high impedance of the aorta (afterload mismatch). Reprinted with permission from Ross (19).