Radionuclide assessment of right and left ventricular function during bicycle exercise in young patients with cystic fibrosis.

Right and left ventricular performance during exercise was evaluated in 31 patients with cystic fibrosis using equilibrium radionuclide cineangiography. There were 21 males and 10 females (mean age 17, range 10.4 to 34.9 yr) with a wide range of clinical involvement. Thirteen patients had arterial desaturation at rest and an additional 4 became desaturated with exercise. Nine patients (29%) were unable to increase their right ventricular ejection fraction more than 5% during exercise. Left ventricular ejection fraction at rest was normal (greater than 55%) in all but 2, and with exercise, performance was impaired in 9 (29%). No relationship was found between resting or exercise radionuclide ejection fraction, M-mode echocardiography or pulmonary function studies. This study suggests that both right and left ventricular dysfunction may occur during stress in patients with cystic fibrosis without other conventional clinical signs or symptoms. Radionuclide cardiac angiography appears to be a safe method of assessing cardiac response to exercise in patients with chronic lung disease, and may be useful in evaluating therapeutic interventions.