[Study of changes in myocardial contraction and left ventricular diastolic regidity after aortocoronary bypass]

Eighteen patients with coronary insufficiency underwent a left ventricular cineangiography before and an average of four months after aorta-to-coronary bi-pass in order to assess the post-operative changes of myocardial contractility and diastolic rigidity. The contractility indices (VCF: mean speed, and VCF max: maximum shortening speed of the equatorial diameter of the left ventricle (% delta theta) were unmodified in the group (I) of fourteen patients with at least one pervious by-pass. On the contrary, a decreased % delta theta was observed in the group (II) of four patients in whom all the by-passes were occluded. The left ventricular end-diastolic pressure (LVEDP), the end-diastolic volume (LVEDV) and the "normalized" rigidity index (K) were unmodified in both groups after operation. The cardiac rate increased in the post-operative period in the group I (p less than 0.01) and the whole of the 18 patients (p less than 0.001); there was a positive correlation (p less than 0.02) between this variation and that of VCF, VCF max. and % delta theta, the significance of which is discussed. Besides there was a negative correlation between the variations of LVEDV and the VCF, and between the equatorial end diastolic diameter of the left ventricle and VCF, VCF max. and % delta theta, both in the pre-operative and the post-operative periods.