Heart failure is the medical term used to describe ineffective pumping of the heart. It is usually caused by structural damage of the heart muscle via a heart attack, high blood pressure, high cholesterol and many other conditions. When blood is not effectively pumped out of the heart and into the body, it backs up and causes fluid retention, particularly in the legs and in the lungs. Drugs used for heart failure aim to increase the effectiveness of the heart and include ACE inhibitors, digoxin and diuretics. In combination, they help the heart fill with blood adequately and diminish the amount of resistance the heart has to pump against.
ACE Inhibitors
Angiotensin-converting enzyme (ACE) inhibitors are drugs that can help prevent the formation of inflammation inside the heart tissue. Inflammation is a common consequence of heart muscle damage and often leads to scar formation. Scarred heart muscle does not have any ability to contract and thus diminishes the amount of blood pumped per beat. ACE inhibitors thereby inhibit scar formation and in this way may halt progression of the disease.
Digoxin
Digoxin is a medication that both slows down the heart rate and increases the strength with which the heart muscle contracts. Slowing the heart rate allows more blood to fill the heart before it gets pumped out, increasing the circulating volume of blood. Squeezing it out more forcefully provides better delivery to the organs and helps prevent pooling of fluid outside of the blood vessels.
Diuretics
Diuretics are medications that stimulate the kidney to move water out of the body as urine. This helps get rid of excess water that builds up in the rest of the tissues and thus helps with the symptoms of heart failure such as edema of the legs and shortness of breath. It also decreases the amount of pressure against which the heart has to pump.
References
- ACP PIER, Journal Club & AHFS DI® Essentials; "Heart Failure"; American College of Physicians; 2010
- Current Diagnosis & Treatment Critical Care; "Congestive Heart Failure"; Shelley Shapiro, MD et al.; 2008
