Transthyretin amyloid cardiomyopathy (ATTR-CM) is an underdiagnosed cause of heart failure and arrhythmia. This differential diagnosis should particularly be considered in older patients with left ventricular hypertrophy (LVH) who are also suffering from heart failure with preserved ejection fraction (HFpEF) or aortic valve stenosis. ATTR-CM is caused either by a genetic variation or by aging processes. The extracellular accumulation of amyloid fibrils in the heart causes a restrictive cardiomyopathy, which leads to typical heart failure symptoms as well as cardiac conduction and repolarization disturbances. Extracardiac problems such as a carpal tunnel syndrome can also be indicative for ATTR-CM. The disease can be diagnosed either by a myocardial biopsy or alternatively by a positive bone scintigraphy with the simultaneous exclusion of monoclonal proteins in blood and urine. Besides a symptomatic treatment, the transthyretin (TTR) stabilizer tafamidis is now available, which can significantly delay the disease progress. In the coming years, the approval of further drugs for the treatment of ATTR-CM is to be expected.