Randomized trial of a hospital-based exercise training program after acute myocardial infarction: cardiac autonomic effects

Department of Medicine, John Hunter Hospital, University of Newcastle, Australia. jleitch@ozemail.com.au

OBJECTIVES: This study sought to determine whether a moderate intensity supervised exercise training program, performed immediately after an uncomplicated acute myocardial infarction, improves recovery in cardiac autonomic function compared with standard advice about activity at home. BACKGROUND: Exercise training has beneficial effects on cardiac autonomic function and may improve prognosis after acute myocardial infarction. METHODS: Thirty-nine male and 10 female patients, mean (+/-SE) age 57 +/- 1 years, with an uncomplicated acute myocardial infarction were randomized to either a 6-week moderate intensity supervised hospital-based exercise training program (exercise group) or to an unsupervised low intensity home walking program (control group). Outcome measures included changes in baroreflex sensitivity (phenylephrine bolus method) and heart rate variability (24-h Holter monitoring) and the endurance time at 85% of peak oxygen consumption. RESULTS: At baseline, there were no significant differences in left ventricular ejection fraction (57 +/- 2% vs. 53 +/- 2%), frequency of anterior infarction (27% vs. 18%) and peak creatine kinase (1,256 +/- 170 vs. 2,599 +/- 295 IU) between the exercise and control groups. Baroreflex sensitivity (10.5 +/- 1.0 vs. 8.4 +/- 1.2 ms/mm Hg) and time domain measures of heart rate variability were also similar. After completion of the program, the exercise group exercised for a median of 15 min (interquartile range 12 to 25) at a workload of 104 +/- 7 W compared with 7 min (interquartile range 3.5 to 12) at a workload of 89 +/- 8 W in the control group (p < 0.01). There were significant (p < 0.001) improvements in baroreflex sensitivity and heart rate variability for the 49 patients combined but no differences between the exercise and control groups. Baroreflex sensitivity improved by 3.4 +/- 1.0 and 1.7 +/- 1.0 ms/mm Hg and the standard deviation of 24-h RR intervals by 36 +/- 6 and 40 +/- 10 ms, respectively (p > 0.1). CONCLUSIONS: A hospital-based exercise training program increased endurance capacity but did not improve recovery of cardiovascular antonomic function after uncomplicated acute myocardial infarction.

This article has been cited by other articles:

				G. E. Billman and M. Kukielka Effect of endurance exercise training on heart rate onset and heart rate recovery responses to submaximal exercise in animals susceptible to ventricular fibrillation J Appl Physiol, January 1, 2007; 102(1): 231 - 240. [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]

				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]

				A. S. Leon, B. A. Franklin, F. Costa, G. J. Balady, K. A. Berra, K. J. Stewart, P. D. Thompson, M. A. Williams, and M. S. Lauer Cardiac Rehabilitation and Secondary Prevention of Coronary Heart Disease: An American Heart Association Scientific Statement From the Council on Clinical Cardiology (Subcommittee on Exercise, Cardiac Rehabilitation, and Prevention) and the Council on Nutrition, Physical Activity, and Metabolism (Subcommittee on Physical Activity), in Collaboration With the American Association of Cardiovascular and Pulmonary Rehabilitation Circulation, January 25, 2005; 111(3): 369 - 376. [Abstract] [Full Text] [PDF]

				A. Loimaala, H. V. Huikuri, T. Koobi, M. Rinne, A. Nenonen, and I. Vuori Exercise Training Improves Baroreflex Sensitivity in Type 2 Diabetes Diabetes, July 1, 2003; 52(7): 1837 - 1842. [Abstract] [Full Text] [PDF]

				P. A. Lanfranchi and V. K Somers Arterial baroreflex function and cardiovascular variability: interactions and implications Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2002; 283(4): R815 - R826. [Abstract] [Full Text] [PDF]

				M. T. La Rovere, C. Bersano, M. Gnemmi, G. Specchia, and P. J. Schwartz Exercise-Induced Increase in Baroreflex Sensitivity Predicts Improved Prognosis After Myocardial Infarction Circulation, August 20, 2002; 106(8): 945 - 949. [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]

				F. Iellamo, J. M. Legramante, M. Massaro, G. Raimondi, and A. Galante Effects of a Residential Exercise Training on Baroreflex Sensitivity and Heart Rate Variability in Patients With Coronary Artery Disease : A Randomized, Controlled Study Circulation, November 21, 2000; 102(21): 2588 - 2592. [Abstract] [Full Text] [PDF]

				A. Loimaala, H. Huikuri, P. Oja, M. Pasanen, and I. Vuori Controlled 5-mo aerobic training improves heart rate but not heart rate variability or baroreflex sensitivity J Appl Physiol, November 1, 2000; 89(5): 1825 - 1829. [Abstract] [Full Text] [PDF]

				A. Stahle, R. Nordlander, and L. Bergfeldt Aerobic group training improves exercise capacity and heart rate variability in elderly patients with a recent coronary event. A randomized controlled study Eur. Heart J., November 2, 1999; 20(22): 1638 - 1646. [Abstract] [PDF]