Original Article

Submaximal Cardiopulmonary Exercise Testing for the Evaluation of Unexplained Dyspnea

Authors: Digant V. Bhatt, MD, MPH, Abraham G. Kocheril, MD

Abstract

Objectives: Gas exchange measurements obtained during submaximal exercise have been shown to provide prognostic and diagnostic information in patients with heart failure (HF) and to differentiate heart versus lung limitations in patients with unexplained dyspnea. The aim of our study was to assess the clinical utility of submaximal cardiopulmonary exercise testing using the Shape-HF equipment in identifying the cause of unexplained dyspnea.

Methods: A total of 65 patients underwent Shape-HF tests from September 2010 to June 2011 for unexplained dyspnea at our center.

Results: Of 65 patients, 39 were men and 26 were women. In this study, 23 patients had preexisting asthma or chronic obstructive pulmonary disease (COPD); 19 patients had a pacemaker (8), an implantable cardioverter defibrillator (2), or a cardiac resynchronization therapy defibrillator (CRT-D) (9). The study revealed that submaximal cardiopulmonary exercise testing provided supportive clinical data for deconditioning, pulmonary limitations (eg, COPD, interstitial lung disease, sleep apnea), pulmonary hypertension, and chronotropic incompetence in 21.5%, 23.1%, 13.8%, and 6.2% of patients, respectively. Pulmonary hypertension was confirmed in 55% of patients by echocardiography and lung problems were confirmed in 40% of patients by pulmonary function test and sleep study. Of nine patients with an implanted CRT-D, optimization of atrioventricular and interventricular programming was performed in seven (78%) using gas exchange monitoring while performing a steady state, low-level treadmill walk.

Conclusions: Submaximal cardiopulmonary exercise testing has strongly suggested the diagnosis of COPD, interstitial lung disease, pulmonary hypertension, and deconditioning and has led to appropriate testing. Based on prior studies, we also used Shape-HF for its approved purpose of optimizing CRT-D programming in patients with HF, leading to clinical improvement.

This content is limited to qualifying members.

Existing members, please login first

If you have an existing account please login now to access this article or view purchase options.

Purchase only this article ($25)

Create a free account, then purchase this article to download or access it online for 24 hours.

Purchase an SMJ online subscription ($75)

Create a free account, then purchase a subscription to get complete access to all articles for a full year.

Purchase a membership plan (fees vary)

Premium members can access all articles plus recieve many more benefits. View all membership plans and benefit packages.

References

1. American Thoracic Society, American College of Chest Physicians. ATS/ACCP statement on cardiopulmonary exercise testing. Am J Respir Crit Care Med 2003;167:211-277.
 
2. Gibbons RJ, Balady GJ, Beasley JW, et al. ACC/AHA Guidelines for Exercise Testing. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Exercise Testing). J Am Coll Cardiol 1997;30:260-311.
 
3. Kleber FX, Vietzke G, Wernecke KD, et al. Impairment of ventilatory efficiency in heart failure: prognostic impact. Circulation 2000;101:2803-2809.
 
4. Johnson RL Jr. Gas exchange efficiency in congestive heart failure. Circulation 2000;101:2774-2776.
 
5. Arena R,Myers J, Aslam SS, et al. Peak VO2 and VE/VCO2 slope in patients with heart failure: a prognostic comparison.Am Heart J 2004;147:354-360.
 
6. Yasunobu Y, Oudiz RJ, Sun XG, et al. End-tidal PCO2 abnormality and exercise limitation in patients with primary pulmonary hypertension. Chest 2005;127:1637-1646.
 
7. Sun XG, Hansen JE, Oudiz RJ, et al. Exercise pathophysiology in patients with primary pulmonary hypertension. Circulation 2001;104:429-435.
 
8. Miller AD, Woods PR, Olson TP, et al. Validation of a simplified, portable cardiopulmonary gas exchange system for submaximal exercise testing. TOSMJ 2010;4:34-40.
 
9. Galie N, Hoeper MM, Humbert M, et al. Guidelines for the diagnosis and treatment of pulmonary hypertension: the Task Force for the Diagnosis and Treatment of Pulmonary Hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS), endorsed by the International Society of Heart and Lung Transplantation (ISHLT). Eur Heart J 2009;30:2493-2537.
 
10. Miyamoto S, Nagaya N, Satoh T, et al. Clinical correlates and prognostic significance of six-minute walk test in patients with primary pulmonary hypertension. Comparison with cardiopulmonary exercise testing. Am J Respir Crit Care Med 2000;161:487-492.
 
11. Woods PR, Frantz RP, Taylor BJ, et al. The usefulness of submaximal exercise gas exchange to define pulmonary arterial hypertension. J Heart Lung Transplant 2011;30:1133-1142.
 
12. Woods PR, Frantz RP, Johnson BD. The usefulness of submaximal exercise gas exchange in pulmonary arterial hypertension: a case series. Clin Med Insights Circ Respir Pulm Med 2010;4:35-40.
 
13. Badesch DB, Champion HC, Sanchez MA, et al. Diagnosis and assessment of pulmonary arterial hypertension. J Am Coll Cardiol 2009;54:S55-S66.
 
14. McNicholl DM, Megarry J, McGarvey LP, et al. The utility of cardiopulmonary exercise testing in difficult asthma.Chest2011;139:1117-1123.
 
15. Martinez FJ, Stanopoulos I, Acero R, et al. Graded comprehensive cardiopulmonary exercise testing in the evaluation of dyspnea unexplained by routine evaluation. Chest 1994;105:168-174.
 
16. Pratter MR, Curley FJ, Dubois J, et al. Cause and evaluation of chronic dyspnea in a pulmonary disease clinic. Arch Intern Med 1989;149:2277-2282.
 
17. MacCarter DJ, Miler FC, Gilmet KB, et al. Acute and chronic improvement in breathing efficiency with exercise based AV/VV CRT optimization. J Card Fail 2008;14:S63.
 
18. Ellenbogen KA, Gold MR, Meyer TE, et al. Primary results from the SmartDelay determined AV optimization: a comparison to other AV delay methods used in cardiac resynchronization therapy (SMART-AV) trial: a randomized trial comparing empirical, echocardiography-guided, and algorithmic atrioventricular delay programming in cardiac resynchronization therapy. Circulation 2010;122:2660-2668.
 
19. Wasserman K, Sun XG, Hansen JE. Effect of biventricular pacing on the exercise pathophysiology of heart failure. Chest 2007;132:250-261.