Exercise-induced pulmonary edema in heart failure.
BACKGROUND
In heart failure (HF) patients, exercise may increase pulmonary capillary hydrostatic pressure and thereby generate pulmonary edema. If pulmonary edema developed, alveolar-capillary membrane conductance (Dm), measured immediately after exercise, would decrease. To test this hypothesis, we measured Dm before and at 2 and 60 minutes after exercise.


RESULTS
We studied 10 HF patients with exercise-induced periodic breathing, 10 with peak o2 < or =15 mL x min(-1) x kg(-1) (severe HF), 10 with o2=15 to 20 mL x min(-1) x kg(-1) (moderate HF), and 10 normal subjects (control). Using the Roughton-Forster technique, we measured carbon monoxide diffusion capacity (DLco) and its components, capillary blood volume (Vc) and Dm, at rest and 2 and 60 minutes after exercise. At rest, DLco and Dm were lowest in periodic breathing and highest in control subjects. Dm decreased in periodic breathing, severe HF, and moderate HF (-7.83+/-3.98, -5.57+/-2.03, and -3.85+/-3.53 mL x min(-1) x mm Hg(-1), respectively; P<0.01) at 2 minutes after exercise but not in control subjects. Vc increased in all groups at 2 minutes and remained elevated at 60 minutes only in periodic breathing. Dm/Vc was decreased in periodic breathing, severe HF, and moderate HF at 2 minutes but not in control subjects. Dm and Dm/Vc remained low at 60 minutes only in periodic breathing.


CONCLUSIONS
Dm decreases after exercise in HF patients but not in control subjects, which suggests a decrease in conductance across the alveolar-capillary barrier, as with pulmonary edema. The reductions were most marked in HF patients with periodic breathing and less reduced in less severe HF.
Centro Cardiologico Monzino, IRCCS, Istituto di Cardiologia, Università di Milano, Via Parea 4, 20138 Milan, Italy. Piergiuseppe.agostoni@CCFM.it
Piergiuseppe
P
Agostoni
Gaia
G
Cattadori
Michele
M
Bianchi
Karlman
K
Wasserman
D000368:Aged; D001810:Blood Volume; D002248:Carbon Monoxide / Q000378:metabolism; D002462:Cell Membrane / Q000502:physiology; D003935:Diagnostic Techniques, Cardiovascular; D004058:Diffusion; D004553:Electric Conductivity; D005080:Exercise Test / Q000009:adverse effects*; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D011650:Pulmonary Alveoli / Q000098:blood supply / Q000503:physiopathology; D011652:Pulmonary Circulation; D011654:Pulmonary Edema / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D012016:Reference Values; D013997:Time Factors
D002248:Carbon Monoxide