Furthermore, severalβ1-AR blockers have been reported to exert cardiodepressant actionunder physiological conditions but improve cardiac function in heart failure[27, 28, 29, 30, 31, 34, 35, 36, 37, 38, 39, 40, 41, 59, 60, 61, 62, 63]. This evidence concerns the gene AR and heart failure.