The aim of this study was to investigate the long-term effects of anthracycline cytostatics upon the frequency-domain characteristics of the signal-averaged electrocardiogram (SAECG) and to evaluate the differences in the frequency content according to gender. At mean follow-up period of 4 years 188 SAECGs were repeatedly performed in 62 childhood cancer survivors, who were in complete remission 1-14 years following anthracycline therapy (mean dose 256 mg/m2). No patient had an abnormal end-of-therapy echocardiogram. The control group consisted of 100 healthy children and young adults. 23% patients vs 5% controls had abnormal area ratio (AR) values (over the 97th percentil of normal controls). Abnormalities in AR remained persistent in 15% of cancer survivors. Frequency-domain analysis revealed significantly higher AR 40-100/0-40 Hz in patients after anthracycline therapy than in controls. Within the patient group significantly higher AR were observed in females than in males. Permanent altered frequency components in SAECGs from cancer survivors, evident particularly in female patients, might signal an increased electrical instability in these patients.

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