There is no single test for heart failure. Blood tests and imaging like echocardiograms, chest x-rays and electrocardiograms (ECG or EKG) are often used to diagnose heart failure, while tests like exercise tolerance testing or angiograms can help identify the cause of your heart failure. Some devices used to manage heart failure include pacemaker, implantable cardioverter-defibrillator, and cardiac resynchronization therapy.