Further Observations on Aorta to Coronary Sinus Anastomosis of Beck in Dogs.

Measurements of retrograde circumflex artery flow, peripheral coronary artery pressure, and electrocardiographic changes induced by circumflex artery ligation were evaluated in an additional 5 Beck #2 operated dogs. 2. Twenty-six Beck #2 operated dogs studied from 4 weeks to one year after the second stage of the operation have been compared with: 1) 41 control dogs, 2) sham Beck #2 operated dogs, 3) defibrillated dogs, and 4) Beck #2 operated dogs 3 months after ligation of the graft. 3. Beck #2 operation results in a significant development of intercoronary arterial communications which persist for at least one year in the presence of a functioning graft and for at least 3 months after ligation of the graft. 4. Sham Beck #2 operated dogs develop intercoronary arterial communications which is in contrast to the lack of such communications following ventricular defibrillation. 5. Further substantiation is provided for previous evidence that in a majority of the Beck #2 operated dogs both functional and anatomical contacts between the perfused venous system and a capillary bed are eventually lost. Consequently earlier conclusions are supported that after about 5 weeks the Beck #2 operation protects normal dogs from the effects of coronary artery ligation by means of intercoronary arterial communications.