ERBB2 and breast cancer: In HER2-positive disease, HER2-directed therapies have improved outcomes, though they can cause cardiac side effects, potentially leading to emergency department (ED) visits.<h4>Objectives</h4>To assesses reasons for ED presentations in breast cancer patients, highlighting subtype-specific differences in reason for presentation, 3-month mortality (3 MM) and the possible association of cardiologic visits with HER2-directed therapy.<h4>Methods</h4>In this retrospective study, visits by breast cancer patients at an Austrian tertiary care ED were analysed.