Abstract
A 55-year-old woman with stage IV breast cancer was diagnosed with heart failure. Her left ventricular ejection fraction (LVEF) had decreased to 37.2%. Chemotherapy-related cardiac dysfunction (CTRCD) was suspected, and standard treatment for heart failure was initiated. After five months, her LVEF remained below 50% since she could not tolerate beta-blockers. Ivabradine was introduced, which remarkably improved her LVEF to 72.6% in only three months. Her myocardium was not dilated, which may be the reason that ivabradine was effective. Ivabradine has shown to be safe and effective in the treatment of CTRCD, and improved activities of daily living of an advanced-stage cancer patient.