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Ventricular contractile interaction following coronary ligation in dogs
1Department of Internal Medicine, Taichung Veterans General Hospital, Taiwan, R.O.C.
Background:
Ventricular interdependence has already been reported. Diastolic ventricular interaction is well studied, but information is rare regarding systolic ventricular interaction and has shown only that maximal acceleration is a sensitive indicator of left ventricular performance. Hence, this study was conducted.
Methods:
Eighteen mongrel dogs were anesthetized and two Millar catheters were advanced from the femoral artery and vein to the left ventricle and pulmonary artery for measurement of pressure, flow and velocity in each. Before and after ligation of the left anterior descending or right coronary artery, both ventricles, dP/dt max, maximum acceleration (MA), time to maximal acceleration (TTMA) were measured simultaneously and the percentage of area change and ventricular wall motion were recorded by two-dimensional echocardiography.
Results:
The percentage of fraction area change decreased significantly when associated with decrease in dP/dt, maximal acceleration and TTMA in both ventricles. The parameters of contractility dP/dt and MA were marked and occurred earlier, after ischemia. In the litigation of LAD, infarct area involved the anteroseptal and apical region and both ventricular dysfunctions were noted. In the litigation of RCA when the interventricular septum motion was preserved, the RV hemodynamic had significant changes including dP/dt and MA, but there was insignificant change in LV.
Conclusions:
Ventricular interaction is less important than the direct effects of coronary occlusion on the myocardium, and the interventricular septum plays a relatively important part in ventricular interaction.