[Laevo-cardiography for the functional evaluation of the ventricle. I. The normal left ventricle].

The possibility of evaluating left ventricular function from lateral laevo-cardiogram has been investigated. A planimetric comparison of the end-diastolic and end-systolic areas of a normal left ventricle shows a 50 to 60% reduction of the systolic area, compared with the diastolic value. Assuming concentric contraction of the left ventricle, the systolic/diastolic reduction in area is proportional to the ejection fraction. This provides a measure for the quantitative evaluation of myocardial function.