Regional myocardial XXXX concentration determines the antidysrhythmic effect in @entity235 after coronary artery occlusion.

@entity296 @entity63 @entity235 @entity3303 @entity943
Ischemic @entity943 were produced in 40 of 47 anesthetized mongrel @entity235 by high ligation of the left anterior descending coronary artery. @entity943 were treated with a single iv bolus of 20, 40, 80, or 120 mg of @entity3303 (L) in order to determine the dose at which approximately 50% of animals had an antidysrhythmic response. Cardiac output and @entity296 ( @entity296 ) were measured by using radionuclide labeled microspheres. @entity3303 concentration [( L]) was measured from samples of arterial and venous blood and normal and @entity63 . All @entity235 treated with 40, 80, or 120 mg of L had an antidysrhythmic effect. However, with 20 mg of L the @entity943 persisted in 12 and resolved in 14. With 20 mg of L, @entity63 myocardial [L] was greater in @entity235 with an antidysrhythmic effect than in those with persistent @entity943 (1.14 +/- 0.12 vs. 0.76 +/- 0.04 micrograms X g-1), but no difference was seen for arterial, venous, and normal myocardial [L]. Ischemic @entity296 was higher in the @entity235 that had an antidysrhythmic effect than in those that did not, 9.8 +/- 1.5 versus 6.9 +/- 1.3% of normal. With 20 mg of L, [L] in @entity63 correlated well with @entity63 @entity296 . The antidysrhythmic response to L had a threshold at a tissue concentration of greater than or equal to 1.0 microgram X g-1 (chi-square = 8.55, P less than 0.005). For this model, the [L] in @entity63 during acute @entity63 correlates with the antidysrhythmic response to L, while the concentration in normal myocardium or blood does not.
