A 47-year-old woman presented for mastectomy and immediate latissimus dorsi flap reconstruction having been diagnosed with carcinoma of the breast 6 months previously. In the preceding months she had received neo-adjuvant chemotherapy with epirubicin, paclitaxel (Taxol) and cyclophosphamide. This had been apparently uncomplicated and she had maintained a remarkably high level of physical activity. She was found to be bradycardic at pre-operative assessment but had no cardiac symptoms. Second degree Mobitz type II atrioventricular block was diagnosed on electrocardiogram, and temporary transvenous ventricular pacing instituted in the peri-operative period. We discuss how evidence-based guidelines would not have been helpful in this case, and how chemotherapy can exhibit substantial cardiotoxicity that may develop over many years. We suggest that patients who have received chemotherapy at any time should have a pre-operative electrocardiogram even if they are asymptomatic.