After-effects of exercise on haemodynamics and muscle sympathetic nerve activity in young patients with dilated cardiomyopathy.

K. Hara, J. S. Floras

Division of Cardiology, University of Toronto, Ontario, Canada.

OBJECTIVE: To determine the after-effects on sympathetic nerve activity and calf and systemic haemodynamics of symptom-limited exercise in young patients with dilated cardiomyopathy. PATIENTS: 14 young patients with dilated cardiomyopathy (mean (SEM) age 35 (2) yr) and 17 healthy controls (age 29 (2) yr). METHODS: Blood pressure, muscle sympathetic nerve activity, calf blood flow, plasma noradrenaline, and stroke volume were recorded during baseline rest and an hour after symptom-limited treadmill exercise (up to 45 min) at 70% of resting heart rate reserve. RESULTS: Before exercise, sympathetic nerve activity (45 (6) v 21 (2) bursts.min-1; P = 0.001) and calf vascular resistance (55 (5) v 31 (3) units; P < 0.0005) were higher in the dilated cardiomyopathy group, and there was a significant correlation between these two variables (r = +0.64; P < 0.001). Patients with ventricular dysfunction exercised for 31 (3) min. In both groups there were significant and similar reductions in diastolic blood pressure, total peripheral resistance, and calf vascular resistance after exercise. Sympathetic nerve activity and plasma noradrenaline were unchanged and there was no longer any relation between muscle sympathetic nerve activity and calf vascular resistance. Cardiac output increased in both groups but, in contrast to healthy controls, mean values for systolic blood pressure and stroke volume (P < 0.005) did not decrease in the cardiomyopathy group. For similar reductions in total peripheral resistance, there were two to three fold greater increases in stroke volume after exercise in patients with left ventricular dysfunction (P < 0.03). There was no relation between exercise duration and the magnitude of these after-effects of exercise in these patients. CONCLUSIONS: In young patients with dilated cardiomyopathy the haemodynamic after-effects of submaximal symptom-limited exercise resemble responses to pharmacological afterload reduction but are not accompanied by reflex sympathetic activation. Sustained calf and systemic vasodilation after exercise were not attenuated, as compared with healthy controls. These cardiac, peripheral, and sympathoneural after-effects provide further support for exercise training as a non-pharmacological adjunct to the management of chronic stable heart failure.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Floras, J. S., Mak, S. (2009). Muscle sympathetic nerve activity in women and men following acute myocardial infarction: a meaningful difference?. Eur Heart J 30: 1692-1694 [Full Text]  
• Oneda, B., Forjaz, C. L. M., Bernardo, F. R., Araujo, T. G., Gusmao, J. L., Labes, E., Abrahao, S. B., Mion, D. Jr., Fonseca, A. M., Tinucci, T. (2008). Low-dose estrogen therapy does not change postexercise hypotension, sympathetic nerve activity reduction, and vasodilation in healthy postmenopausal women. Am. J. Physiol. Heart Circ. Physiol. 295: H1802-H1808 [Abstract] [Full Text]  
• Kleiber, A. C., Zheng, H., Schultz, H. D., Peuler, J. D., Patel, K. P. (2008). Exercise training normalizes enhanced glutamate-mediated sympathetic activation from the PVN in heart failure. Am. J. Physiol. Regul. Integr. Comp. Physiol. 294: R1863-R1872 [Abstract] [Full Text]  
• Watson, A. M. D., Hood, S. G., Ramchandra, R., McAllen, R. M., May, C. N. (2007). Increased cardiac sympathetic nerve activity in heart failure is not due to desensitization of the arterial baroreflex. Am. J. Physiol. Heart Circ. Physiol. 293: H798-H804 [Abstract] [Full Text]  
• Usui, K., Bradley, T. D., Spaak, J., Ryan, C. M., Kubo, T., Kaneko, Y., Floras, J. S. (2005). Inhibition of Awake Sympathetic Nerve Activity of Heart Failure Patients With Obstructive Sleep Apnea by Nocturnal Continuous Positive Airway Pressure. J Am Coll Cardiol 45: 2008-2011 [Abstract] [Full Text]  
• Chan, C. T., Harvey, P. J., Picton, P., Pierratos, A., Miller, J. A., Floras, J. S. (2003). Short-Term Blood Pressure, Noradrenergic, and Vascular Effects of Nocturnal Home Hemodialysis. Hypertension 42: 925-931 [Abstract] [Full Text]  
• Notarius, C.F., Azevedo, E.R., Parker, J.D., Floras, J.S. (2002). Peak oxygen uptake is not determined by cardiac noradrenaline spillover in heart failure. Eur Heart J 23: 800-805 [Abstract] [Full Text]  
• Kubo, T., Azevedo, E. R., Newton, G. E., Parker, J. D., Floras, J. S. (2001). Lack of evidence for peripheral alpha1- adrenoceptor blockade during long-term treatment of heart failure with carvedilol. J Am Coll Cardiol 38: 1463-1469 [Abstract] [Full Text]  
• Notarius, C. F., Atchison, D. J., Rongen, G. A., Floras, J. S. (2001). Effect of adenosine receptor blockade with caffeine on sympathetic response to handgrip exercise in heart failure. Am. J. Physiol. Heart Circ. Physiol. 281: H1312-H1318 [Abstract] [Full Text]  
• Notarius, C. F., Atchison, D. J., Floras, J. S. (2001). Impact of heart failure and exercise capacity on sympathetic response to handgrip exercise. Am. J. Physiol. Heart Circ. Physiol. 280: H969-H976 [Abstract] [Full Text]  
• Notarius, C. F., Floras, J. S. (2001). Limitations of the use of spectral analysis of heart rate variability for the estimation of cardiac sympathetic activity in heart failure. Europace 3: 29-38 [Abstract]  
• Notarius, C.F., Ando, S., Rongen, G.A., Floras, J.S. (1999). Resting muscle sympathetic nerve activity and peak oxygen uptake in heart failure and normal subjects. Eur Heart J 20: 880-887 [Abstract]  
• Abramson, B. L., Ando, S.-i., Notarius, C. F., Rongen, G. A., Floras, J. S. (1999). Effect of Atrial Natriuretic Peptide on Muscle Sympathetic Activity and Its Reflex Control in Human Heart Failure. Circulation 99: 1810-1815 [Abstract] [Full Text]