[Function of the left ventricle in the acute phase of myocardial infarct]

In the acute phase of myocardial infarction in 22 patients intraventricular pressure measurements (left and right heart catheters) were performed. In addition to this in 17 cases a qualitative and quantitative angiocardiographical judgment of the function of the left ventricle was done. A group of 9 patients with healthy heart served as control group. The group with infarction showed typical findings deviating from the normal. Stroke volume, cardiac output and stroke work of the left ventricle were significantly decreased. The systolic ejection fraction which was highly significantly reduced in contrast to the normal value proved as a particularly sensitive index. The contractility parameters dp/dt max. and VCE(dp/dt max.) were also highly significantly reduced; aortic mean pressure and heart rate did not show any significant changes. A compensation of the decrease of the heart function depending on contractility is achieved in the acute phase of the myocardial infarction by a significant increase of the wall stiffness, in which case apparently the ventricle practically exclusively by this means strives for an optimum filling pressure in order to maintain a sufficiently large stroke volume. The practically unchanged enddiastolic ventricle volume excluded at least for the uncomplicated infarction in the acute stage an essential participation of Frank-Starling's compensation mechanism.