Heart Failure with Reduced Ejection Fraction

Heart failure with reduced ejection fraction, known internationally as HFrEF, is a type of heart failure that occurs because the muscle of the left ventricle has weakened and cannot contract strongly. Ejection fraction is the percentage of blood in the left ventricle that is pumped out each time the heart beats. In a healthy heart the value is 50% or more, while in this type it is 40% or less.

A weak muscle is usually followed by enlargement of the left ventricle. An enlarged heart pumps less and less efficiently, the mitral valve can start to leak, and the body holds on to salt and water. This change in shape is called remodeling, and the majority of heart failure medicines work by slowing it. The symptoms are the same as heart failure in general: shortness of breath, tiring easily, and swelling in the legs. How severe the symptoms are does not always match the ejection fraction number, so even people with mild symptoms still need full treatment.

Common Causes

The main cause is coronary artery disease, especially after a heart attack, covered on the Ischemic Cardiomyopathy page. Other causes are dilated cardiomyopathy, including inherited forms, long-standing hypertension, valve disease, excessive alcohol use, side effects of cancer treatment, myocarditis, and a heart rate that stays too fast for a long time.

Four Main Classes of Medicine

The ESC 2021 and AHA/ACC/HFSA 2022 guidelines recommend four classes of medicine for almost everyone with this type: an ACE inhibitor or ARNI, a beta blocker, a mineralocorticoid receptor antagonist (MRA), and an SGLT2 inhibitor. Each has been proven to reduce hospital stays and deaths, and the benefits add up when they are used together. Your doctor starts them and raises the doses gradually while monitoring blood pressure, heart rate, kidney function, and potassium. Diuretics are added to relieve shortness of breath and swelling.

Pumping Function Can Improve

In some patients, the ejection fraction rises above 40% after several months of treatment. This is called heart failure with improved ejection fraction. Even with improvement, medicines are generally continued, because research shows that stopping them can cause pumping function to fall again. If the ejection fraction stays at 35% or less, your doctor will discuss devices such as an ICD, which prevents sudden death from dangerous ventricular rhythms, or resynchronization therapy, which coordinates the contraction of both ventricles.

Diagnosis starts with your symptoms, a physical examination, an ECG, and an NT-proBNP or BNP test. Echocardiography confirms an ejection fraction of 40% or less, while also assessing the size of the ventricles, wall motion, and the valves. The next step is to look for the cause, because treating the cause can improve pumping function.

If coronary artery disease is suspected, your doctor will recommend coronary angiography or CT coronary angiography. Cardiac MRI helps distinguish scarring from a past heart attack from other cardiomyopathies, inflammation, or buildup of substances in the heart muscle. Blood tests assess kidney function, potassium, complete blood count, thyroid, and iron levels. The ECG is also used to measure the width of the QRS complex, which determines whether resynchronization therapy will help. Echocardiography is repeated after about three months of medication as the basis for deciding on an ICD.

See a cardiologist if shortness of breath, tiredness, or swelling appears for the first time, especially if you have had a heart attack or have family members with cardiomyopathy. If you have already been diagnosed, contact your doctor early if any of the following occur.

• You gain 2 kg or more in 3 days.
• Shortness of breath or swelling is worse than usual.
• You feel dizzy when standing up or your blood pressure is much lower than usual.
• You receive a shock from your ICD.
• Go to the emergency room right away if you have severe shortness of breath at rest, fainting, or chest pain.