Objectives: Although trastuzumab therapy is known to be associated with congestive heart failure, its arrhythmogenic potential has not been studied in detail. The purpose of this study was to determine the acute influence of trastuzumab infusion on electrocardiogram (ECG) parameters in patients with metastatic breast cancer.
Patients and methods: Twenty patients with HER2 overexpressing metastatic breast cancer and normal cardiac function were enrolled in this single-centre prospective study. Standard 12-lead ECG recordings were performed at baseline and after trastuzumab infusion (2 mg/kg given over 30 min). P-wave durations, QT and RR intervals were measured and QT dispersion (QTd) and P-wave dispersion (Pd) were calculated.
Results: In comparison with baseline, no statistically significant change in any ECG parameters, including QT and RR intervals, P wave durations, Pd and QTd, was observed after infusion of trastuzumab.
Conclusion: In this study, no abnormality of atrial and ventricular depolarisation and repolarisation, indicated by Pd and QTd, was detected after infusion of trastuzumab. As Pd and QTd are both known to be associated with increased risk of serious arrhythmias and sudden death, it would appear that trastuzumab has no acute arrhythmogenic potential related to cardiac depolarisation and repolarisation.