[Laevo-cardiography for estimating the function of the left ventricle. II Mitral insufficiency]

1. The normal left ventricle is characterised by the relationship between end-diastolic volume and ejection fraction. (Reduction in the lateral projectional area by 50--60% during systole, as compared with the end-diastolic projectional area.)--2. The functionally sufficient left ventricle in the presence of haemodynamically significant mitral insufficiency shows and increasing end-diastolic measurement with increasing volume.--3. End-diastolic projectional area, up to 85 cm.2, and end-diastolic filling pressure, up to 20 mHg are associated, apart from odd exceptions, with normal contraction indeces, i.e. a normal ejection fraction. --4. Within these magnitudes of area and pressure, there is a demonstrable relationship between area/pressure quotient and contracture index. --5. Insufficiency of muscular contraction of the left ventricle in mitral insufficiency is characterised, with reduced normal or enlarged, end-diastolic areas and normal, or increased, end-diastolic filling pressure by an abnormal relationship between ejection fraction and end-diastolic volume (contraction index less than 50%). --6. In mitral insufficiency which is haemodynamically significant, some of the residual blood may be used as a supplement for ventricular filling.