This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Posel, D. Articles by Opie, L. H. Search for Related Content PubMed PubMed Citation Articles by Posel, D. Articles by Opie, L. H.

Circulation, Vol 80, 138-145, Copyright © 1989 by American Heart Association

ARTICLES

Exercise training after experimental myocardial infarction increases the ventricular fibrillation threshold before and after the onset of reinfarction in the isolated rat heart

D Posel, T Noakes, P Kantor, M Lambert and LH Opie
MRC Ischaemic Heart Disease Research Unit, Department of Medicine, South Africa.

Previous work has shown that exercise training increases the ventricular fibrillation threshold of the isolated perfused rat heart. The aim of our study was to determine whether exercise training that begins after myocardial infarction can similarly increase the ventricular fibrillation threshold. Rats that had suffered an experimental myocardial infarction were subject to a running training program. Thereafter, the ventricular fibrillation threshold was measured before and after the onset of acute reinfarction induced by a second coronary artery ligation. Ventricular fibrillation thresholds were significantly elevated in trained rats during normoxia (13.7 +/- 2.2 vs. 4.7 +/- 0.8 mA, p less than 0.01) and during acute ischemia (6.8 +/- 1.6 vs. 3.0 +/- 0.7 mA, p less than 0.02). The myocardial cyclic AMP level was lower in the nonischemic zone of the trained hearts (0.21 +/- 0.01 vs. 0.28 +/- 0.01 nmol/g, p less than 0.05), which also had lower cyclic AMP levels after epinephrine challenge (0.50 +/- 0.05 vs. 0.73 +/- 0.09 nmol/g, p less than 0.01; 1.41 +/- 0.11 vs. 1.85 +/- 0.09 nmol/g, p less than 0.02 after epinephrine 10(- 7) M and 5 x 10(-6) M injection, trained vs. untrained). Both propranolol 10(-6) M and epinephrine 5 x 10(-7) M attenuated the difference in ventricular fibrillation thresholds before and after second coronary artery ligation and eliminated any difference in cyclic AMP content of both the nonischemic and ischemic myocardial tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				G. E. Billman Cardiac autonomic neural remodeling and susceptibility to sudden cardiac death: effect of endurance exercise training Am J Physiol Heart Circ Physiol, October 1, 2009; 297(4): H1171 - H1193. [Abstract] [Full Text] [PDF]

				H. L. Lujan, S. L. Britton, L. G. Koch, and S. E. DiCarlo Reduced susceptibility to ventricular tachyarrhythmias in rats selectively bred for high aerobic capacity Am J Physiol Heart Circ Physiol, December 1, 2006; 291(6): H2933 - H2941. [Abstract] [Full Text] [PDF]

				G. E. Billman, M. Kukielka, R. Kelley, M. Moustafa-Bayoumi, and R. A. Altschuld Endurance exercise training attenuates cardiac beta2-adrenoceptor responsiveness and prevents ventricular fibrillation in animals susceptible to sudden death Am J Physiol Heart Circ Physiol, June 1, 2006; 290(6): H2590 - H2599. [Abstract] [Full Text] [PDF]

				M. Kukielka, D. R. Seals, and G. E. Billman Cardiac vagal modulation of heart rate during prolonged submaximal exercise in animals with healed myocardial infarctions: effects of training Am J Physiol Heart Circ Physiol, April 1, 2006; 290(4): H1680 - H1685. [Abstract] [Full Text] [PDF]

				G. E. Billman and M. Kukielka Effects of endurance exercise training on heart rate variability and susceptibility to sudden cardiac death: protection is not due to enhanced cardiac vagal regulation J Appl Physiol, March 1, 2006; 100(3): 896 - 906. [Abstract] [Full Text] [PDF]

				H. L. Collins, A. M. Loka, and S. E. DiCarlo Daily exercise-induced cardioprotection is associated with changes in calcium regulatory proteins in hypertensive rats Am J Physiol Heart Circ Physiol, February 1, 2005; 288(2): H532 - H540. [Abstract] [Full Text] [PDF]

				G. E. Billman Aerobic exercise conditioning: a nonpharmacological antiarrhythmic intervention J Appl Physiol, February 1, 2002; 92(2): 446 - 454. [Abstract] [Full Text] [PDF]