|
| HOME | SUBSCRIPTIONS | CURRENT ISSUE | PAST ISSUES | CARDIOSOURCE | SEARCH | HELP | FEEDBACK |
|
|
|
|||||||||
|
|||||||||||
|
J Am Coll Cardiol, 1997; 29:590-596 © 1997 by the American College of Cardiology Foundation |
Division of Circulatory Physiology, Columbia Presbyterian Medical Center, New York, New York 10032, USA.
OBJECTIVES: This study investigated whether maximal exercise performance can be improved by acutely decreasing the work of breathing in these patients. BACKGROUND: Exertional dyspnea is a frequent limiting symptom in patients with heart failure. It may result from increased work of breathing. METHODS: Fifteen patients with heart failure and nine age-matched normal subjects underwent two maximal exercise tests. Subjects exercised twice in randomized, single-blind manner using room air (RA) and a 79% helium/21% oxygen mixture (He). Respiratory gas analysis, Borg scale recordings of perceived dyspnea and near infrared spectroscopy of an accessory respiratory muscle were obtained during exercise. RESULTS: In normal subjects there was no significant difference in peak oxygen uptake (Vo2) ([mean +/- SD] RA 38 +/- 8 vs. He 35 +/- 7 ml/kg per min), exercise duration (RA 724 +/- 163 vs. He 762 +/- 123 s) or peak minute ventilation (RA 97 +/- 27 vs. He 97 +/- 28 liters/min, all p = NS). Only three of nine control subjects thought that exercise with the He mixture was subjectively easier. In contrast, patients with heart failure exercised an average of 146 s longer with the He mixture (RA 868 +/- 293 vs. He 1,014 +/- 338, p < 0.01). Peak Vo2 (RA 19 +/- 4 vs. He 18 +/- 5 ml/kg per min) and peak minute ventilation (RA 53 +/- 12 vs. He 53 +/- 15 liters/min) were unchanged (both p = NS). The respiratory quotient at peak exercise was lower with the He mixture (RA 1.05 +/- 0.08 vs. He 0.98 +/- 0.06, p < 0.05). Thirteen of the 15 patients thought that exercise with the He mixture was subjectively easier (p < 0.02 vs. control group). CONCLUSIONS: In patients with heart failure, pulmonary factors, including respiratory muscle work and airflow turbulence, contribute to limiting exercise performance. Therapeutic interventions aimed at attenuating work of breathing may be beneficial.
This article has been cited by other articles:
|
|
 |
|
  A. Borghi-Silva, C. Carrascosa, C. C. Oliveira, A. C. Barroco, D. C. Berton, D. Vilaca, E. B. Lira-Filho, D. Ribeiro, L. E. Nery, and J. A. Neder Effects of respiratory muscle unloading on leg muscle oxygenation and blood volume during high-intensity exercise in chronic heart failure Am J Physiol Heart Circ Physiol, June 1, 2008; 294(6): H2465 - H2472. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. L. Fleg Improving Exercise Tolerance in Chronic Heart Failure: A Tale of Inspiration? J. Am. Coll. Cardiol., April 29, 2008; 51(17): 1672 - 1674. [Full Text] [PDF]
|
|
|
|
 |
|
 L. M. Romer and M. I. Polkey Exercise-induced respiratory muscle fatigue: implications for performance J Appl Physiol, March 1, 2008; 104(3): 879 - 888. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. D. Witt, J. A. Guenette, J. L. Rupert, D. C. McKenzie, and A. W. Sheel Inspiratory muscle training attenuates the human respiratory muscle metaboreflex J. Physiol., November 1, 2007; 584(3): 1019 - 1028. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. D. Miller, C. A. Smith, S. J. Hemauer, and J. A. Dempsey The effects of inspiratory intrathoracic pressure production on the cardiovascular response to submaximal exercise in health and chronic heart failure Am J Physiol Heart Circ Physiol, January 1, 2007; 292(1): H580 - H592. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. D. Miller, S. J. Hemauer, C. A. Smith, M. K. Stickland, and J. A. Dempsey Expiratory threshold loading impairs cardiovascular function in health and chronic heart failure during submaximal exercise J Appl Physiol, July 1, 2006; 101(1): 213 - 227. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Laghi and M. J. Tobin Disorders of the Respiratory Muscles Am. J. Respir. Crit. Care Med., July 1, 2003; 168(1): 10 - 48. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
ATS/ACCP Statement on Cardiopulmonary Exercise Testing Am. J. Respir. Crit. Care Med., January 15, 2003; 167(2): 211 - 277. [Full Text] [PDF]
|
|
|
|
|
|
P. D. HUGHES, N. HART, C.-H. HAMNEGÅRD, M. GREEN, A. J. S. COATS, J. MOXHAM, and M. I. POLKEY Inspiratory Muscle Relaxation Rate Slows during Exhaustive Treadmill Walking in Patients with Chronic Heart Failure Am. J. Respir. Crit. Care Med., May 1, 2001; 163(6): 1400 - 1403. [Abstract] [Full Text]
|
|
|
|
|
|
C. A. Harms, T. J. Wetter, C. M. St. Croix, D. F. Pegelow, and J. A. Dempsey Effects of respiratory muscle work on exercise performance J Appl Physiol, July 1, 2000; 89(1): 131 - 138. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Y. Sue Exertional Dyspnea in Congestive Heart Failure : Living Longer and Doing More? Chest, July 1, 2000; 118(1): 5 - 7. [Full Text] [PDF]
|
|
|
|
|
|
A. Chauhan, G. Sridhar, R. Clemens, B. Krishnan, D. D. Marciniuk, and C. G. Gallagher Role of Respiratory Function in Exercise Limitation in Chronic Heart Failure Chest, July 1, 2000; 118(1): 53 - 60. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. D. Johnson, K. C. Beck, L. J. Olson, K. A. O'Malley, T. G. Allison, R. W. Squires, and G. T. Gau Ventilatory Constraints During Exercise in Patients With Chronic Heart Failure Chest, February 1, 2000; 117(2): 321 - 332. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Opasich, N. Ambrosino, G. Felicetti, R. Aquilani, E. Pasini, D. Bergitto, A. Mazza, F. Cobelli, and L. Tavazzi Heart failure-related myopathy. Clinical and pathophysiological insights Eur. Heart J., August 2, 1999; 20(16): 1191 - 1200. [Abstract] [PDF]
|
|
|
|
|
|
P. D. HUGHES, M. I. POLKEY, M. LOU HARRIS, A. J. S. COATS, J. MOXHAM, and M. GREEN Diaphragm Strength In Chronic Heart Failure Am. J. Respir. Crit. Care Med., August 1, 1999; 160(2): 529 - 534. [Abstract] [Full Text]
|
|
| HOME | SUBSCRIPTIONS | CURRENT ISSUE | PAST ISSUES | CARDIOSOURCE | SEARCH | HELP | FEEDBACK |
