Faculty Collaboration Database

Interactions of halothane with isoproterenol and epinephrine on canine epicardial conduction velocity at normal and elevated potassium levels. Acta Anaesthesiol Scand 2001 Aug;45(7):885-92

Date

07/27/2001

Pubmed ID

11472292

DOI

10.1034/j.1399-6576.2001.045007885.x

Scopus ID

2-s2.0-0034900132 (requires institutional sign-in at Scopus site)

Abstract

BACKGROUND: Halothane is known to potentiate catecholamine-induced depression of conduction velocity in Purkinje fibers but not endocardial muscle fibers. The purpose of this study was to examine the interactions of halothane with epinephrine and isoproterenol on canine epicardial conduction velocity at moderately elevated extracellular potassium concentration ([K]0).

METHODS: Epicardial muscle strips (10x10x2 mm) were superfused with Tyrode's solution containing 4 or 8 mM [K]0 in the presence of 5 microM epinephrine or 1 microM isoproterenol with or without 0.8 mM halothane. Conduction velocity in the longitudinal and transverse directions relative to epicardial fiber orientation was recorded during alternate stimulation in each direction.

RESULTS: In the presence of halothane, a change from 4 to 8 mM [K]0 decreased (P< or =0.05) longitudinal and transverse conduction velocities by 26% and 21%, respectively. Isoproterenol alone at 4 and 8 mM [K]0 depressed (P<0.05) both longitudinal and transverse conduction velocities. However, the depression of longitudinal conduction velocity by isoproterenol at 4 mM [K]0 was attenuated by halothane. Epinephrine with or without halothane depressed (P<0.05) both longitudinal and transverse conduction velocities at 8 but not at 4 mM [K]0.

CONCLUSION: The results do not support a synergistic interaction between halothane and epinephrine on myocardial conduction but do demonstrate depression of conduction by epinephrine at 8 mM [K+]0, a potassium ion concentration comparable to those reported following epinephrine infusions.

Author List

Camara AK, Turner LA, Bosnjak ZJ

Author

Amadou K. Camara PhD Professor in the Anesthesiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adrenergic beta-Agonists
Anesthetics, Inhalation
Animals
Dogs
Electric Stimulation
Epinephrine
Halothane
Heart Conduction System
Isoproterenol
Myocardium
Pericardium
Potassium
Vasoconstrictor Agents