Respiratory Medicine CME
Volume 2, Issue 1 , Pages 33-35, 2009

Exercise-induced cardiac costraint by the lungs

  • Roberto Cassandro

      Affiliations

    • Unità Operativa di Pneumologia, Ospedale San Giuseppe, Milano Cuore, via San Vittore 12, 20123 Milano, Italy
    • ,
  • Sergio Harari

      Affiliations

    • Unità Operativa di Pneumologia, Ospedale San Giuseppe, Milano Cuore, via San Vittore 12, 20123 Milano, Italy
    • Corresponding Author InformationCorresponding author. Tel.: +39 02 85994580; fax: +39 02 85994400.
    • ,
  • Achille Bianchi

      Affiliations

    • Unità Operativa di Pneumologia, Ospedale San Giuseppe, Milano Cuore, via San Vittore 12, 20123 Milano, Italy
    • ,
  • Piergiuseppe Agostoni

      Affiliations

    • Centro Cardiologico Monzino, IRCCS, Istituto di Cardiologia Univerisità di Milano, Italy

Received 10 June 2008; accepted 1 July 2008.

Article Outline

Summary 

A patient of fourty-five years old male, with severe emphysema, underwent bullectomy. He was studied, before and one year after surgery, by standard pulmonary function test and cardiopulmonary exercise test. We found that before bullectomy, tidal volume increases up to 45W and flattens thereafter. After bullectomy tidal volume increases trough the entire exercise.

 

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Introduction 

Cardiopulmonary interactions during exercise have been extensively studied.1, 2, 3 The presence of a pulmonary constrain on the heart has been suggested in several disease such as COPD and heart failure.2, 4, 5, 6 However, the possibility to show a therapeutic intervention able to increase the cardiac function by acting on the pulmonary constrain forces has been suggested but never proved.3 We report a case of a subject with severe emphysema who, after surgical bullectomy, improved his exercise capacity through a reduction of the cardiac constraint by the lungs.

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Clinical report 

Fourty-five years old male, with severe emphysema, who underwent bullectomy, was studied, before and one year after surgery, by standard pulmonary function test and cardiopulmonary exercise test. The latter was performed on a cyclo-ergometer, with a ramp protocol (15W/min). After bullectomy pulmonary function and exercise capacity improved (Table 1). The VO2/work relationship is of specific interest. Before bullectomy (Fig. 1, panel A), above 45W, the VO2 increase flattens. After bullectomy (Fig. 1, panel B) the VO2/work relationship is a constant straight line even when a higher workload is achieved. Also ventilation kinetics are of some interest. Ventilation and tidal volume are higher after bullectomy (Table 1). Before bullectomy, tidal volume increase up to 45 Watts and flattens thereafter (Fig. 2). After bullectomy tidal volume increases trough the entire exercise.

Table 1. Pulmonary function and cardiopulmonary exercise results before (pre) and 1 year after bullectomy (post).
PrePost
FVC [L (%)]3.99 (84)4.81 (103)
FEV1 [L (%)]1.89 (49)2.74 (72)
TLC [L (%)]7.57 (106)7.39 (105)
RV [L (%)]3.58 (171)2.59 (123)
pVO2 [L/min]0.8441.374
pVE [L/min]40.559.1
pVT [L]1.5932.131

FVC=forced vital capacity, FEV1=forced expiratory volume in 1 second, TLC=total lung capacity, RV=residual volume, pVO2=oxygen consumption at peak exercise, pVE=ventilation at peak exercise, pVT=tidal volume at peak exercise.

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Discussion 

The VO2/work relationship is an index of efficiency of the O2 delivery toward the working muscles. The flattening of the relationship means a reduction of cardiac output usually due to exercise induced cardiac ischemia.7, 8 In the present case the flattening of the VO2/work relationship observed before bullectomy is due to exercise induced increase in lung stiffness which interfere with either right and left ventricle preload as well as the external work of the heart. The latter is the work performed by the heart to “push and pull” against the lungs during systole and diastole.1 In the presurgical exercise tidal volume increase flattens when VO2/work relationship flattens suggesting that the lungs are unable to further expand and act as a cardiac constrictor. Furthermore, the disappearance of the flattening of both VO2/work and tidal volume/work relationships after surgery, even at higher work rate, is another evidence that in this case the lung constrains the heart. The present is the first documentation of lung constraint forces on the heart which reduces cardiac performance in the absence of a primitive cardiac disease.3

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References 

  1. Butler J. The heart is in good hands. Circulation. 1985;67:1163–1168
  2. Butler J. The heart in not always in good hands. Chest. 1990;97:453–460
  3. Agostoni PG, Marenzi GC, Sganzerla P, Assanelli E, Guazzi M, Perego GB, et al. Lung-heart interaction as a substrate for the improvement in exercise capacity after body fluid volume depletion in moderate congestive heart failure. Am J Cardiol. 1995;76:793–798
  4. O'Donnell DE, Webb KA, Bertley JC, Chau LK, Conlan AA. Mechanisms of relief of exertional breathlessness following unilateral bullectomy and lung volume reduction surgery in emphysema. Chest. 1996;110:18–27
  5. Agostoni PG, Marenzi GC, Pepi M, Doria E, Salvioni A, Perego G, et al. Isolated ultrafiltration for moderate heart failure. J Am Coll Cardiol. 1993;21:424–431
  6. Agostoni G, Cattadori G, Guazzi M, Palermo P, Bussotti M, Marenzi G. Cardiomegaly as a possibile cause of lung dysfunction in patients with heart failure. Am Heart J. 2000;140:e24
  7. Berardinelli R, Lacalaprice F, Carle F, Minnucci A, Cianci G, Perna G, et al. Exercise-induced myocardial ischemia detected by cardiopulmonary exercise testing. Eur Heart J. 2003;24:1304–1313
  8. Bussotti M, Apostolo A, Andreini D, Palermo P, Contini M. Agostoni PG Cardiopulmonary evidence of exercise-induced silent ischaemia. Eur J Cardiovasc Prev Rehabil. 2006;13:249–253

PII: S1755-0017(08)00078-X

doi:10.1016/j.rmedc.2008.07.017

Respiratory Medicine CME
Volume 2, Issue 1 , Pages 33-35, 2009

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