Reduced resistances of septal artery collateral channels after cardiac sympathectomy.

We have shown that chronic cardiac sympathectomy reduces coronary collateral resistances. The present experiments in isolated dog hearts delineated the role of intramyocardial collateral channels from the septal (SEP) to the circumflex (CIRC), left anterior descending (LAD), and right (RT) coronary arteries in this phenomenon. In 11 controls and 8 2-wk sympathectomized hearts, a retrograde flow technique was used to determine collateral resistances between the epicardial arteries (CIRC, LAD, RT). Collateral resistances between the CIRC and LAD and between the LAD and RT were 42-68% less in sympathectomized hearts (P less than 0.05). Collateral resistances from the SEP to each epicardial artery were determined from retrograde flows simultaneously collected on each epicardial artery when the SEP was the only vessel perfused. Collateral resistances from the SEP to the CIRC and LAD were 51-59% less in the sympathectomized hearts (P less than 0.05). Thus, intramyocardial channels from the SEP to the left coronary arteries show reduced resistances after sympathectomy and can provide a substantial portion of the increased collateral flow to these vessels.