Heart Failure

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Our heart, like the hearts of all vertebrate animals, is an extremely strong pump. The heart keeps blood flowing properly, thereby supplying much needed oxygen and nutrients to the body’s cells and removing toxins and carbon dioxide from the cells. In its resting phase, called diastole, the heart fills with blood, which it pumps out to the body when it contracts during systole. The heart contraction during systole produces a heartbeat. Sometimes the heart muscle becomes stiff or weak which compromises the heart’s ability to pump blood. This condition is called heart failure (HF), aka congestive heart failure (CHF). The term “heart failure” is a bit of a misnomer because the heart has not “failed,” but rather its ability to pump blood efficiently has been compromised. HF causes blood and fluid to back up in the body, including in the lungs, abdomen, and legs.

HF affects about 40 million people worldwide. It can be caused by many things, but the most common risk factors are untreated high blood pressure, coronary artery disease and heart attacks, diabetes, obesity, smoking, and genetic factors. When HF occurs in younger people, it is sometimes caused by a viral illness which attacks the heart muscle, causing it to weaken. This is called a cardiomyopathy. Signs of HF include weakness or decreased energy, trouble breathing on exertion (dyspnea on exertion, or DOE), trouble breathing when lying flat causing one to need to sit up to breathe (orthopnea), weight gain, leg swelling, and abdominal swelling or fullness.

Clinicians may use a number of tools to diagnose HF. A detailed history is performed to look for any changes in overall health and lifestyle. The exam looks for signs of excess fluid such as enlarged neck veins (jugular vein distension or JVD), fluid in the abdomen (ascites), and fluid in the legs (edema). In HF, the heart enlarges which can be seen on chest X ray and detected on EKG. An echocardiogram, or ultrasound of the heart, looks for heart enlargement plus it measures the ejection fraction, or EF. The EF is the amount of blood the heart pumps out during systole. Normally, the heart pumps out between 60 to 65% of the blood that fills it during diastole. The EF in HF may be 40% or below, while severe HF may be below 20%, which often necessitates a defibrillator to be implanted in the chest to correct sudden, often fatal arrythmias and may eventually require a transplant. HF is classified using the NYHA system from class I (mild symptoms) to class IV (severe symptoms with EF < 20%).

Basic HF treatment includes regular exercise, quitting smoking, losing weight, and treating diabetes, high blood pressure, high cholesterol, and sleep apnea. One of the mainstays of treatment is removal of excess fluid with diuretics. Lowering blood pressure, including causing arteries to widen (vasodilation), improves HF. The goal is to keep patients out of the hospital. Treatment includes ACE inhibitors (i.e. lisinopril), ARBs (i.e. losartan), and beta blockers (i.e. metoprolol). More severe cases may benefit from an angiotensin receptor-neprolysin inhibitor (Entresto) or a mineralocorticoid inhibitor (spironolactone and Inspra). Finally, those with type II diabetes and HF may benefit from SGLT2 inhibitors (known as gliflozins) such as Steglatro, Invokana, Jardiance, or Farxiga.

For more information go to the National Library of Medicine at

medlineplus.gov/heartfailure.html

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By Peter Galvin, MD

 

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