Maximal exercise testing and gas exchange in patients with chronic atrial fibrillation.
To evaluate the response of patients with chronic atrial fibrillation to exercise, 50 men (mean age 65 +/- 8 years) with atrial fibrillation underwent a maximal exercise test using respiratory gas exchange techniques. Patients were classified by the presence (n = 29) or absence ("lone atrial fibrillation," n = 21) of underlying heart disease. Responses were evaluated at a standard submaximal work load (3.0 mph, [4.8 km/h] 0% grade), at the gas exchange anaerobic threshold and at maximal exercise. For all 50 patients, the mean maximal oxygen uptake was 20.6 ml/kg per min, which approximates 85% of the aerobic capacity predicted for age-matched normal individuals. Patients with lone atrial fibrillation demonstrated normal exercise capacity in contrast to patients with atrial fibrillation and known heart disease (22.7 +/- 5 versus 19.1 +/- 5.0 ml/kg per min, p less than 0.05). The mean maximal heart rate (176 +/- 30 beats/min) was approximately 20 beats/min higher than that expected for age, was extremely variable and accounted for only 8% of the variance in maximal oxygen uptake. Maximal heart rate in subjects with lone atrial fibrillation was higher than that of subjects with atrial fibrillation and known heart disease (189 +/- 32 versus 166 +/- 24 beats/min, p less than 0.01). Stepwise regression analysis revealed that maximal systolic blood pressure accounted for 19% of the variance in maximal oxygen uptake (VO2 max), suggesting that systolic function is an important determinant of exercise performance in atrial fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)
Atwood
J E
JE
Cardiology Section, Veterans Administration Medical Center, Long Beach, California 90822.
Myers
J
J
Sullivan
M
M
Forbes
S
S
Friis
R
R
Pewen
W
W
Callaham
P
P
Hall
P
P
Froelicher
V
V
D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000150:complications / Q000503:physiopathology*; D002908:Chronic Disease; D003327:Coronary Disease / Q000150:complications; D005080:Exercise Test; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D011659:Pulmonary Gas Exchange; D012044:Regression Analysis