Electrocardiographic abnormalities in childhood cancer survivors treated with cardiotoxic therapy: a systematic review

Purpose The purpose of this study is to assess the available literature on the prevalence and risk factors of electrocardiographic (ECG) abnormalities after cardiotoxic treatment in childhood cancer survivors (CCS). Methods A literature search was performed within MEDLINE, EMBASE, and CENTRAL (1966‐11/2020) and reference lists of relevant studies. Studies were eligible for inclusion if they reported ECG abnormalities ≥2 years after cancer diagnosis in ≥50 CCS treated with anthracyclines, RT involving the heart region and/or mitoxantrone. Information about population, treatment, outcome, and risk factors were extracted and risk of bias was assessed. Results Of 934 identified publications, 10 studies were included. Outcome definitions, treatment regimens, follow‐up period, and risk of bias varied. These ECG abnormalities and prevalences were reported: major (5%‐23%) and minor (12%) abnormalities according to the Minnesota Code, rhythm abnormalities (0%‐12%), conduction abnormalities (0.3%‐7.1%), depolarization abnormalities (0%), and repolarization abnormalities (0%‐65%). The reported risk factors of ECG abnormalities (two studies) are male sex, anthracyclines, RT involving the heart region, and hypertension, although results were not univocal between studies and abnormalities. Conclusions Multiple ECG abnormalities have been described in CCS ≥2 years from diagnosis, some of which can have important implications. Future research is needed to evaluate the exact long‐term incidence and risk factors, and to investigate their clinical relevance and relation with cardiac dysfunction or future cardiac events. This could improve cardiac surveillance for CCS.