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.
Agostoni
Piergiuseppe
P
Centro Cardiologico Monzino, IRCCS, Istituto di Cardiologia, Università di Milano, Via Parea 4, 20138 Milan, Italy. Piergiuseppe.agostoni@CCFM.it
Cattadori
Gaia
G
Bianchi
Michele
M
Wasserman
Karlman
K
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