CARDIAC DYSFUNCTION LATE AFTER CARDIOTOXIC THERAPY FOR CHILDHOOD-CANCER

Despite a wealth of data documenting acute cardiac injury from anthracycline therapy and/or mediastinal radiotherapy used for childhood cancer, little information Is available on the long term consequence of these insults. Twenty nine patients (mean age 15 +/- 4.3 years) from The Late Effects Follow-Up Clinic For Childhood Cancer study, who had been in continuous, complete remission and off: chemotherapy for a minimum of 2 years (mean follow-up 7.2 +/- 3.2) were stud led. All patients had normal ejection fractions before and during cancer therapy and all were in New York Heart Association class I at the time of study. Systolic and diastolic functions were assessed by 2-dimensional echocardiography, Doppler flow velocity, and radionuclide angiography, and results were compared with normal control subjects. Left ventricular mass and mass index were significantly reduced in the patient population. Fractional shortening was decreased overall and end-systolic wall stress was much higher in patients than in controls. However, contractility, as assessed by the relation of wall stress to rate-corrected velocity of shortening, was decreased by greater than or equal to 2 SDs in only 6 of 28 patients, and the force-mass relation was actually increased in the patient group as a whole. Mitral valve inflow velocities were significantly increased but the pattern was abnormal. These results suggest a pattern consistent with a thin walled, compliant left ventricle with reduced muscle mass performing under above-normal levels of wall stress. Contractility measurements were normal or increased in the group, but some patients clearly demonstrated development of reduced contractile function. Close follow-up of survivors of aggressive cancer therapy will be necessary as the natural history of these cardiac function abnormalities becomes known.