ARB refers to angiotensin ll receptor antagonists and ACEI refers to angiotensin converting enzyme inhibitors, both of which are first-line antihypertensive drugs in clinical practice. Angiotensin II receptor antagonists, by blocking the tissue angiotensin II receptor subtype angiotensin I, thereby blocking the vasoconstriction, water and sodium retention, and remodeling effects of angiotensin II. Angiotensin-converting enzyme inhibitors inhibit angiotensin-converting enzyme, resulting in a decrease in angiotensin II production, and also inhibit bradykinin causing a decrease in bradykinin degradation. Angiotensin II receptor antagonists and angiotensin-converting enzyme inhibitors, in addition to their antihypertensive effects, can also inhibit myocardial remodeling, so they are commonly used in the treatment of chronic heart failure and post-myocardial infarction, and can improve the prognosis of patients.