Fentanyl, Na-pentobarbital and halothane influence myocardial infarct size

Abstract

We investigated the effects of three anesthetics on the size of myocardial infarction and on blood flow distribution within the myocardial wall. Myocardial infarcts were induced in 34 dogs by ligating a coronary artery for 90 minutes, and permitting reflow for 90 minutes. The anesthetics used were fentanyl, Na-pentobarbital, and halothane. Under halothane the mean blood pressure (BP) during coronary artery ligation was 113 +/- 2/82 +/- 2 mm Hg and the heart rate (HR) was 135 +/- 2/min. Under fentanyl, the BP was 143 +/- 3/91 +/- 2 mm Hg and HR 99 +/- 3/min. Under Na-pentobarbital, BP was 141 +/- 2/104 +/- 2 mm Hg and HR 146 +/- 2/min. A higher mean BP combined with a slower HR, as seen under fentanyl, was associated with the smallest infarct (24 +/- 8%). Low BP and higher HR, as seen under halothane, was associated with the largest infarct (51 +/- 5%). Na-pentobarbital, with a higher BP but also a faster HR, resulted in an infarct size of 32 +/- 5%. We conclude that a higher mean BP combined with a slower HR might favor the preservation of a larger mass of vulnerable myocardial tissue in a totally occluded coronary artery.

Acute hemodynamic effects of coronary artery ligation in conscious rats

“…In ether-anesthetized rats, Pfeffer et al (22) reported a reduced MAP but unchanged HR 3 weeks after CAL. Similarly conflicting results have been obtained in cats (19) and dogs (15,16,18).…”

“…General anesthetics have been shown to suppress cardiovascular nervous reflexes like the carotid sinus baroreflexes (7) and chemoreflexes (28). This could, obviously, influence hemodynamie responses to CAL as was shown in a study by Mergner et al (18) in dogs, where CAL, using three different general anesthetics, resulted in three different hemodynamic response patterns. In addition, we avoided effects of acute surgery since thorax surgery itself has been found to have a cardiac depressive effect, which may mask the effects of CAL (26).…”

Cardioprotective effects of desflurane: effect of timing and duration of administration in rat myocardium

“…Pentobarbital reduces myocardial infarction after 90 min of ischaemia in dogs. 21 Another study shows that infarcts were larger in dogs treated with pentobarbital as compared with a conscious dog model. 22 Moreover, Cope and colleagues 1 have shown that pentobarbital does not increase the extent of myocardial infarction in the rabbit myocardium.…”