Heart failure is a condition where the heart is unable to pump sufficient blood to meet the body’s needs. This can happen if the heart muscle becomes damaged, weakened, or stiff. When blood flow is reduced, muscles and organs do not receive the required oxygen and nutrients, leading to various symptoms. A specific classification of this condition is heart failure with reduced ejection fraction (HFrEF), which identifies a functional problem with the heart’s main pumping chamber.
Defining Reduced Ejection Fraction
Ejection fraction (EF) is a measurement of how much blood the left ventricle pumps out with each contraction. The left ventricle is the heart’s primary pumping chamber, sending oxygen-rich blood to the rest of the body. EF is expressed as a percentage; for instance, an ejection fraction of 60% indicates that 60% of the blood in the left ventricle is pushed out with each heartbeat. It quantifies the heart’s pumping efficiency.
A healthy heart does not eject all the blood from the ventricle with each beat. A normal left ventricular ejection fraction is between 50% and 70%. When the heart muscle weakens, its ability to contract forcefully diminishes, resulting in less blood being pumped out. Heart failure with reduced ejection fraction (HFrEF) is diagnosed when the EF is 40% or less. This is also referred to as systolic heart failure, as it relates to the systole phase when the heart muscle contracts.
An EF measurement between 41% and 49% is classified as mildly reduced. This range may indicate heart damage or the early stages of heart failure. The measurement of ejection fraction is a standard method used to diagnose and track the status of heart failure.
Common Causes and Symptoms
HFrEF is often linked to underlying conditions that have damaged or weakened the heart muscle over time. One of the most prevalent causes is coronary artery disease, where arteries supplying blood to the heart become narrowed. A previous heart attack is another significant cause, as it can lead to permanent damage to the heart muscle, impairing its ability to pump effectively.
Long-standing high blood pressure also contributes to HFrEF by forcing the heart to work harder, which can weaken the muscle over time. Other causes can also lead to a reduced ejection fraction:
- Diseases of the heart valves, such as aortic stenosis where the valve opening is narrowed
- Conditions that directly affect the heart muscle, known as cardiomyopathies
- Viral infections that cause inflammation of the heart muscle (myocarditis)
- Irregular heart rhythms (arrhythmias)
Individuals with HFrEF experience a distinct set of symptoms. Shortness of breath is a primary complaint, which may occur with physical activity or when lying down. Persistent fatigue and weakness are also common. Another frequent symptom is swelling (edema) in the legs, ankles, and feet, caused by fluid retention as the heart’s poor pumping function leads to fluid backing up in the body.
The Diagnostic Process
Diagnosing HFrEF involves a physical examination, a review of symptoms, and several specific tests. The primary diagnostic tool is the echocardiogram, often called an “echo.” This non-invasive test uses sound waves to create moving pictures of the heart, allowing doctors to assess its chambers and valves and directly measure the left ventricular ejection fraction.
Another common test is the electrocardiogram (ECG or EKG), which records the heart’s electrical activity. An ECG can identify irregular heart rhythms or evidence of past heart attacks that could be the underlying cause of the weakened heart muscle. A chest X-ray may also be performed to check the heart’s size and look for fluid buildup in the lungs.
Blood tests are also a component of the diagnostic process. Doctors measure the levels of a hormone called B-type natriuretic peptide (BNP) or its precursor, NT-proBNP. The heart releases these substances in higher amounts when it is under stress, and elevated levels are a strong indicator of heart failure.
Modern Treatment Strategies
Treatment for HFrEF is multifaceted, focusing on medications, lifestyle adjustments, and in some cases, implantable devices. Medical therapy is built upon four main classes of drugs: angiotensin receptor-neprilysin inhibitors (ARNIs), beta-blockers, mineralocorticoid receptor antagonists (MRAs), and sodium-glucose cotransporter-2 (SGLT2) inhibitors. Each class works through different mechanisms to reduce strain on the heart and improve its function.
ARNIs, which often replace older ACE inhibitors or ARBs, work to relax blood vessels and reduce sodium and fluid retention. Beta-blockers help by slowing the heart rate and lowering blood pressure, which decreases the heart’s oxygen demand. MRAs are a type of diuretic that helps the body get rid of excess salt and water while retaining potassium. SGLT2 inhibitors, originally developed for diabetes, have been shown to be effective for HFrEF patients regardless of whether they have diabetes.
Lifestyle changes are also a component of managing HFrEF. A low-sodium diet is recommended to help prevent fluid retention. Monitoring daily fluid intake may also be advised by a healthcare provider. Regular physical activity, tailored to the individual’s ability, can improve functional capacity and quality of life.
For some individuals, implantable devices may be necessary. An implantable cardioverter-defibrillator (ICD) can be used to monitor the heart rhythm and deliver an electrical shock to correct dangerous, fast arrhythmias, which can be a risk in HFrEF. Cardiac resynchronization therapy (CRT), which uses a specialized pacemaker, can help the heart’s ventricles contract in a more coordinated and efficient manner, improving the overall pumping function.
Managing Daily Life with HFrEF
Active participation in one’s own care is a large part of living with HFrEF. Taking all prescribed medications exactly as directed is fundamental, as these drugs are designed to work together to improve heart function and reduce symptoms. Skipping doses or stopping medication can lead to a worsening of the condition.
A key practice for managing HFrEF is monitoring for fluid retention, which can indicate that the condition is worsening. This is done by weighing yourself every morning at the same time, after using the restroom and before eating. A sudden weight gain of two to three pounds in a day or five pounds in a week should be reported to a healthcare provider.
Recognizing and promptly reporting worsening symptoms is another part of daily management. Keeping a log of daily weight and any symptoms can be a helpful tool for discussions with your healthcare team.
Regular follow-up appointments are necessary to monitor the condition and the effectiveness of the treatment plan. These visits allow the healthcare team to make any needed adjustments to medications or other therapies.