Mechanisms of actions of ACE inhibitors, Angiotensin receptor blockers (ARBs), Beta-blockers, Aldosterone receptor antagonists (ARAs), Digoxin, Ivabradine, Angiotensin Receptor-Neprilysin Inhibitor, ARNIs (sacubitril/valsartan), Diuretics, Vasodilators. Role of RAAS, sympathetic system and natriuretic peptide system in pathophysiology of Congestive heart failure (CHF) and rational for treatment of HF.