CARDIAC DYSFUNCTION LATE AFTER CARDIOTOXIC THERAPY FOR CHILDHOOD-CANCER

Despite a wealth of data documenting acute cardiac injury from anthrac ycline therapy and/or mediastinal radiotherapy used for childhood canc er, little information Is available on the long term consequence of th ese insults. Twenty nine patients (mean age 15 +/- 4.3 years) from The Late Effects Follow-Up Clinic For Childhood Cancer study, who had bee n in continuous, complete remission and off: chemotherapy for a minimu m 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. Syst olic and diastolic functions were assessed by 2-dimensional echocardio graphy, Doppler flow velocity, and radionuclide angiography, and resul ts were compared with normal control subjects. Left ventricular mass a nd mass index were significantly reduced in the patient population. Fr actional 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 onl y 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 su ggest a pattern consistent with a thin walled, compliant left ventricl e with reduced muscle mass performing under above-normal levels of wal l stress. Contractility measurements were normal or increased in the g roup, but some patients clearly demonstrated development of reduced co ntractile function. Close follow-up of survivors of aggressive cancer therapy will be necessary as the natural history of these cardiac func tion abnormalities becomes known.