From 60% to 5% in 12 Weeks: A Trastuzumab-Induced Left Ventricular Ejection Fraction Drop.

Trastuzumab is the first-line therapy for human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, trastuzumab is associated with cardiotoxicity. It manifests with an asymptomatic reduction of left ventricular ejection fraction (LVEF) and is reversible after discontinuation.