Complete atrioventricular block and torsade de pointes due to dose-dense epirubicin and cyclophosphamide therapy.

The dose-dense epirubicin and cyclophosphamide (EC) therapy for breast cancer decreases the risk of cancer recurrence and death. However, epirubicin and cyclophosphamide also cause cardiotoxicity, and cardiomyopathy is the most well-known related adverse effect. A 58-year-old woman presented to our hospital with palpitations 2 weeks after her final dose-dense EC therapy for breast cancer. Holter electrocardiogram (ECG) showed transitory complete atrioventricular block (CAVB) and torsade de pointes. A 12-lead ECG showed QT prolongation in addition to CAVB. Patients receiving dose-dense EC therapy should be monitored more carefully with ECG due to their risk of fatal arrhythmias.