Delayed Trastuzumab-induced Cardiotoxicity Leading to Severe Left Ventricular Dysfunction

An 81-year-old woman presented to our hospital with dyspnea. She had been treated with trastuzumab for nine years. Chest radiography revealed pleural effusion. Transthoracic echocardiography revealed dyskinesis of the interventricular septum (IVS). Cardiac magnetic resonance imaging revealed increased native T1 values at the interventricular septum and apex, indicating myocardial edema or fibrosis in these areas. A transthoracic echocardiogram after half a year revealed an increase in LVEF from 25% to 48%. Serial transthoracic echocardiography and cardiac magnetic resonance imaging were useful for evaluating the cardiac structure and function in the present case of delayed trastuzumab-induced myocardial injury.