Systolic heart failure occurs when the heart muscle becomes weak and cannot pump blood effectively. Common causes include heart attacks, high blood pressure, heart valve disease, and cardiomyopathy. Symptoms often include shortness of breath, fatigue, leg swelling, and difficulty exercising.
As a board-certified internist, I often tell patients that systolic heart failure sounds frightening, but understanding it is the first step toward managing it well. Many people live long, meaningful lives with this condition once they know what is happening inside their heart and why.
Systolic heart failure happens when the heart muscle becomes weak and cannot pump blood out to the body the way it should. The heart still fills with blood, but it does not squeeze strongly enough. Because of this, the body and vital organs may not get the oxygen and nutrients they need.
Doctors often call systolic heart failure heart failure with reduced ejection fraction, or HFrEF. The “ejection fraction” is the percentage of blood the heart pushes out with each beat. A normal ejection fraction is usually 55% or higher. In systolic heart failure, that number is lower.
What Happens to the Heart in Systolic Heart Failure
Think of the heart as a strong pump. In systolic heart failure, the pump becomes stretched, damaged, or weakened. When the heart cannot squeeze well, blood backs up in the lungs and body. This backup causes many of the symptoms people notice, such as breathing problems and swelling.
Over time, the heart may enlarge as it tries to compensate. Unfortunately, this usually makes the pumping problem worse instead of better.
Common Symptoms of Systolic Heart Failure
Symptoms can start slowly and may be mild at first. Some people think they are just “getting older” or “out of shape.” Common symptoms include:
- Shortness of breath, especially with activity or when lying flat
- Feeling tired or weak most of the time
- Swelling in the feet, ankles, legs, or abdomen
- Rapid weight gain from fluid buildup
- Coughing or wheezing, especially at night
- Trouble exercising or doing daily activities
- Feeling lightheaded or dizzy
- Fast or irregular heartbeat
Symptoms often worsen over time if the condition is not treated.
The Most Common Causes of Systolic Heart Failure
Systolic heart failure does not usually happen overnight. It develops after years of damage or strain on the heart.
One of the most common causes is a prior heart attack. When a heart attack occurs, part of the heart muscle is damaged due to lack of blood flow. Scar tissue replaces healthy muscle, and scar tissue cannot pump. The more muscle damaged, the weaker the heart becomes.
High blood pressure is another major cause. When blood pressure stays high for many years, the heart must work harder to pump blood. Over time, the heart muscle thickens and then weakens, leading to systolic failure.
Coronary artery disease can also cause systolic heart failure. Narrowed arteries reduce blood flow to the heart muscle. Even without a full heart attack, poor blood flow over time weakens the heart.
Cardiomyopathy is a disease of the heart muscle itself. It can be inherited or caused by infections, toxins, or unknown reasons. In dilated cardiomyopathy, the heart chambers stretch and become thin, making it hard for the heart to pump effectively.
Heart valve disease is another important cause. Valves that are too narrow or leaky force the heart to work harder. Over time, this extra work weakens the heart muscle.
Long-term heavy alcohol use can damage heart muscle cells directly. This condition is sometimes called alcoholic cardiomyopathy. The good news is that stopping alcohol early can sometimes improve heart function.
Certain infections, especially viral infections of the heart muscle (myocarditis), can lead to systolic heart failure. Some people recover fully, while others are left with permanent damage.
Chemotherapy drugs and toxins may damage the heart muscle. This is why heart function is often monitored during cancer treatment.
Abnormal heart rhythms, especially fast rhythms that last for long periods, can weaken the heart. When the heart beats too fast for too long, it does not have time to fill properly, leading to reduced pumping strength.
Congenital heart disease, meaning heart problems present at birth, can also cause systolic heart failure later in life. Even repaired defects may place long-term stress on the heart.
Risk Factors That Make Systolic Heart Failure More Likely
Certain factors increase the chance of developing systolic heart failure. These include:
- High blood pressure
- Diabetes
- Smoking
- Obesity
- High cholesterol
- Family history of heart disease
- Sleep apnea
- Lack of physical activity
Many of these risk factors are preventable or treatable, which is why early care is so important.
Why Symptoms Often Get Worse Over Time
When the heart cannot pump well, the body tries to compensate. Hormones are released to tighten blood vessels and retain salt and water. At first, this helps maintain blood pressure. Over time, however, these changes make heart failure worse by increasing fluid buildup and strain on the heart.
That is why medications are so important in systolic heart failure. They block these harmful hormone effects and protect the heart.
When to Seek Medical Help
You should seek medical care if you notice new or worsening shortness of breath, sudden weight gain, swelling in your legs, or chest pain. Early diagnosis allows treatment to begin before the heart becomes more damaged.
Living With Systolic Heart Failure
While systolic heart failure is a serious condition, treatment has improved dramatically. Medications, lifestyle changes, and sometimes devices can improve symptoms and extend life. Many patients feel better and stay active with proper care.
Understanding the cause of systolic heart failure helps guide treatment and gives patients a sense of control over their health.