The association of trastuzumab with atrial fibrillation and heart failure in breast cancer patients in routine clinical practice: a population-based propensity score matching and competing risk model analysis.

Trastuzumab in real-world practice was associated with an increased risk of HF, but was not associated with an increased risk of Af in BC patients. Trastuzumab-induced arrhythmogenic effects may be masked by concurrent heart-protecting measures, more prominent roles of comorbidities or concurrent medications under real-world settings. Further studies are required.