Therapeutic advances in cancer management have improved patients’ prognosis. Nevertheless, these treatments come with a price including cardiac toxicity. Arrhythmias were reported as a side effect of several chemotherapeutic drugs but still remain a rare complication. The aim of this study was to assess the prevalence of cancer-treatment induced arrhythmias and conduction disorders in our unit.

We conducted a prospective longitudinal study in the cardio-oncology unit of Casablanca from January 2017 to December 2019 where all the patients, all types of cancer confounded, were followed-up according to the ESC 2016 guidelines, with clinical, electrical, biological and echocardiographic evaluation of cardiac tolerance to cardiotoxic cancer-treatments.

Out of a total number of 1318 patients (mean age= 53±9 yo, 91.2% female), the most frequent neoplasy was breast cancer in 84.6%, followed by ENT, kidney and colon cancers (6,2%, 3,1%, 1,8%). 77.6% received a chemotherapy based on anthracyclines (AC60 protocol in 62,8% and FEC100 protocol in 37,2%), 69,7% on cyclophosphamide, 39,8% on 5-Flurouracil (5FU), 56,1% on taxanes and 17.3% on cisplatin. 53.7% breast cancer patients were under HER2 inhibitors and 56.8% had radiotherapy. A total of 107 patients developed cardiotoxicity (8,1%) with 13 cases of arrhythmias (12,1%). Atrial fibrillation (AF) was found in 5 patients (4 under anthracyclines and 1 under cisplatin), sinusal bradychardia in 2 patients, ventricular hyperexcitability in 1 patient under 5-FU. Conduction disorders in our serie were prolonged QT interval in 4 patients under anthracyclines and cyclophosphamide, and 1 complete atrioventricular block in 1 patient under anthracyclines and taxanes.

Arrhythmias and conduction disorders secondary to chemotherapeutic drugs are a rare but possible complication, hence the importance of clinical and electrical evaluation of patients under cardiotoxic treatments.