Left Ventricular Function After Formation of Myocardial Tunnels Used for Internal Mammary Artery Implantation
Left ventricular function curves and maximum dp/dt were determined at constant heart rate and aortic pressure in 20 dogs before and after the formation of myocardial tunnels used for internal mammary artery implantation. In five dogs, the internal mammary arteries were implanted in anterior and posterior myocardial tunnels developed by blunt dissection midway between endocardium and epicardium and extending one-half the ventricular length. In five dogs, tunnels of similar length and location were made with a scalpel. In ten additional dogs, myocardial infarction was produced by left anterior descending artery ligation six weeks prior to the time of study. Tunnels were created in these animals by blunt dissection and, after the inscription of function curves, the tunnels were enlarged with a scalpel. A repeat function curve was then inscribed. In 19 of the 20 animals, neither the creation of long myocardial tunnels nor the implantation of freely bleeding internal mammary arteries produced significant immediate alteration in the function of the normal or the functionally impaired myocardium.
- © 1969 American Heart Association, Inc.