Heart failure is a serious, long-term condition where the heart muscle cannot pump enough blood to meet the body’s demands, leading to inadequate circulation. Systolic heart failure, also known as heart failure with reduced ejection fraction (HFrEF), is a specific type where the heart’s ability to contract effectively is impaired. The left ventricle, the heart’s main pumping chamber, becomes too weak to squeeze blood forcefully enough during the contraction phase. This inability to eject a sufficient volume of blood affects the entire body.
The Mechanism of Reduced Pumping Power
Systolic heart failure involves a fundamental loss of the heart’s contractile strength in the left ventricle. The term “systole” refers to the phase when the ventricles contract to eject blood into the circulation. When this muscle is weakened, the force of contraction is significantly reduced, meaning less blood is pushed out with each beat.
This mechanical inefficiency is measured by the Ejection Fraction (EF), which is the percentage of blood leaving the left ventricle with each contraction. A normal EF is 50% or higher. In systolic heart failure, the EF drops to 40% or lower, which is why it is formally termed Heart Failure with Reduced Ejection Fraction (HFrEF).
When the heart cannot pump blood forward efficiently, pressure builds up backward into the circulatory system. Insufficient emptying of the left ventricle causes fluid to back up first into the lungs, leading to pulmonary congestion. This fluid backup eventually extends to the rest of the body, creating systemic congestion.
Primary Causes and Risk Factors
The underlying cause of systolic heart failure is damage to the heart muscle that impairs its ability to contract. The most frequent cause is Coronary Artery Disease (CAD), where narrowed or blocked coronary arteries limit the blood supply to the heart muscle. This lack of oxygen can cause portions of the muscle to die, resulting in a Myocardial Infarction, or heart attack.
Chronic high blood pressure (hypertension) is another leading cause because it forces the heart to pump against increased arterial resistance. Over time, this sustained overwork causes the heart muscle to stretch and weaken, eventually leading to failure. Conditions like diabetes can also contribute by causing long-term damage to the heart muscle and blood vessels.
Other conditions that weaken the ventricular muscle include viral infections causing inflammation (myocarditis), heart valve diseases, and long-standing irregular heart rhythms (arrhythmias). Excessive alcohol or drug use can also be toxic to the heart muscle, leading to cardiomyopathy. These varied causes all result in a damaged, poorly functioning left ventricle.
Recognizing Common Symptoms
The physical manifestations of systolic heart failure stem from the body’s inability to circulate blood and manage fluid effectively. The most common symptom is dyspnea (shortness of breath), which occurs due to fluid congestion in the lungs. This breathlessness may initially only happen during activity, but later occurs even at rest or when lying flat (orthopnea).
Chronic fatigue and generalized weakness are frequently reported, resulting from the poor delivery of oxygenated blood to the muscles and organs. Fluid retention (edema) is another hallmark sign, typically appearing as swelling in the legs, ankles, and feet.
This fluid buildup occurs because blood backing up from the heart forces liquid out of the capillaries and into the surrounding tissues. Patients may also experience a persistent cough, sometimes producing pink-tinged or frothy mucus, which signals advanced pulmonary fluid. A sudden, unexplained weight gain of three or more pounds in a single day indicates worsening fluid retention.
Diagnostic Procedures and Ejection Fraction Measurement
Systolic heart failure is confirmed through physical examination, laboratory work, and specialized imaging tests. The most essential diagnostic tool is the echocardiogram (echo), which uses sound waves to create a moving image of the heart. This test allows physicians to visualize the heart’s structure and measure the Left Ventricular Ejection Fraction (LVEF).
The LVEF value defines systolic heart failure, with a measurement of 40% or less confirming the diagnosis of HFrEF. The echocardiogram also provides details on the size of the heart chambers, wall thickness, and heart valve function. Other supporting tests include blood work, such as measuring B-type natriuretic peptide (BNP) or N-terminal pro-BNP (NT-proBNP).
These natriuretic peptides are hormones released by the heart muscle when it is stressed; elevated levels suggest heart failure. A chest X-ray may also be performed to look for signs of an enlarged heart or fluid in the lungs. An electrocardiogram (ECG) records the heart’s electrical activity, helping to detect irregular rhythms or evidence of past heart attacks.
Comprehensive Management and Treatment Strategies
Management of systolic heart failure focuses on reducing the heart’s workload, controlling symptoms, and preventing the condition from worsening. Pharmacological treatment uses specific classes of medications to interrupt the harmful hormonal responses that occur when the heart is damaged. Foundational therapy for HFrEF includes a combination of four core drug classes:
- Angiotensin Receptor-Neprilysin Inhibitors (ARNIs), Angiotensin-Converting Enzyme (ACE) Inhibitors, or Angiotensin Receptor Blockers (ARBs), which relax blood vessels and lower blood pressure.
- Beta-blockers, which slow the heart rate and decrease the force of contraction, allowing the heart to rest.
- Mineralocorticoid Receptor Antagonists (MRAs), which help block harmful hormones.
- Sodium-Glucose Co-transporter 2 (SGLT2) Inhibitors, which are used to reduce fluid retention and improve cardiovascular outcomes.
Diuretics (water pills) are utilized to manage fluid buildup associated with heart failure symptoms, decreasing swelling and breathlessness. Beyond medication, significant lifestyle modifications are necessary for effective long-term management. Patients are advised to restrict daily sodium intake to reduce fluid retention and monitor their daily body weight.
A sudden weight increase can indicate fluid retention and signal the need for a medication adjustment. Regular physical activity, often guided by a cardiac rehabilitation program, is encouraged for stable patients to improve heart function and quality of life. In advanced cases where medication is insufficient, advanced therapies may be considered, such as implanting a specialized pacemaker or an Implantable Cardioverter Defibrillator (ICD) to manage dangerous heart rhythms.