[Is thoracic epidural anesthesia beneficial to myocardial ischemia?--Influence of hemodynamics].

The effects of thoracic epidural anesthesia (TEA) on regional myocardial blood flow (RMBF) and hemodynamics were evaluated in open-chest dogs with coronary artery stenosis. In the 6 dogs with pressure-rate quotients (PRQ) of greater than 0.8, TEA caused a significant increase of the ratio of endocardial to epicardial RMBF in the ischemic region and tended to increase the ratio of RMBF in the ischemic to normal area, resulting in improved myocardial ischemia. There was no reduction of myocardial ischemia in the 11 dogs with PRQ of less than 0.8. The hemodynamic effects determine whether TEA is favorable for the ischemic heart or not. It appears that PRQ is useful as an indicator of myocardial oxygen balance during TEA.