In congestive heart failure, the ability of the heart to pump enough blood to satisfy the physiological needs of the body is reduced. This condition has a variety of causes, including damaged heart valves, myocardial infarction, hypertension, vitamin B deficiency, and genetic mutations. When subsequent blood flow to the kidneys is reduced, the kidneys respond by increasing the secretion of renin from the juxtaglomerular apparatus. Renin converts the inactive angiotensinogen into angiotensin I, which is converted to angiotensin II (AII) by angiotensin converting enzyme (ACE).  AII can have negative effects on the cardiovascular system after events such as heart failure and myocardial infarction. AII causes arterial vasoconstriction and hypertension, resulting in an increase in afterload, increasing the resistance against which the heart works. Additionally, chronic increase in production of AII is associated with structural changes to the myocardium which reduces the functionality of the heart.
In heart failure patients, fosinopril increases exercise tolerance and lowers the frequency of events associated with worsening heart failure, such as dyspnea, the need for supplemental diuretics, fatigue, and hospitalizations.