Ejection fraction (EF) is a measurement used by cardiologists to assess how well the heart pumps blood. It is defined as the percentage of blood that is ejected from the left ventricle with each contraction. A normal ejection fraction ranges from 55% to 70%. When the EF falls below 40%, it is considered low and indicates heart failure or cardiomyopathy, which can lead to serious health complications.
Understanding the causes of low ejection fraction is crucial for effective treatment and management of heart conditions.
This article explores the various factors that can lead to a decrease in ejection fraction, including heart diseases, lifestyle factors, and other medical conditions.
Heart Diseases And Conditions
Coronary Artery Disease (CAD)
CAD is the most common cause of low ejection fraction. It occurs when the coronary arteries, which supply blood to the heart muscle, become narrowed or blocked due to plaque buildup (atherosclerosis). This reduces blood flow to the heart, causing damage to the heart muscle and decreasing its ability to pump effectively.
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Myocardial Infarction (Heart Attack)
A heart attack occurs when a coronary artery is completely blocked, cutting off blood supply to a part of the heart muscle.
The affected muscle tissue can become damaged or die, leading to a reduction in the heart’s pumping ability and, consequently, a lower ejection fraction.
Cardiomyopathy
Cardiomyopathy refers to diseases of the heart muscle. There are several types:
Dilated Cardiomyopathy: The heart’s chambers enlarge and weaken, reducing its ability to pump blood.
Hypertrophic Cardiomyopathy: The heart muscle thickens abnormally, making it harder for the heart to pump blood.
Restrictive Cardiomyopathy: The heart muscle becomes rigid and less elastic, limiting the heart’s ability to fill with blood between beats.
Heart Valve Diseases
Malfunctioning heart valves can also cause low ejection fraction. For instance, aortic stenosis (narrowing of the aortic valve) or mitral regurgitation (leakage of the mitral valve) can lead to increased workload on the heart, weakening the heart muscle over time.
Congenital Heart Defects
Some people are born with structural heart defects that can affect the heart’s pumping efficiency. These congenital heart defects can lead to a lower ejection fraction if not corrected.
Other Medical Conditions
High Blood Pressure (Hypertension)
Chronic high blood pressure forces the heart to work harder to pump blood against the increased resistance. Over time, this extra effort can weaken the heart muscle, reducing its efficiency and leading to a lower ejection fraction.
Diabetes
Diabetes can damage blood vessels and increase the risk of coronary artery disease and high blood pressure. Both conditions can contribute to heart muscle damage and a reduced ejection fraction.
Obesity
Obesity increases the risk of developing heart disease, high blood pressure, and diabetes. Additionally, excess body weight puts extra strain on the heart, which can weaken the heart muscle and lower the ejection fraction.
Thyroid Disorders
Both hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) can affect heart function.
Hypothyroidism can slow down the heart rate and reduce the force of heart contractions, while hyperthyroidism can lead to an irregular heartbeat and heart failure.
Chronic Kidney Disease
Chronic kidney disease can lead to fluid buildup in the body, including around the heart, making it harder for the heart to pump effectively.
This can contribute to a lower ejection fraction.
What Causes Low Ejection Fraction of The Heart
Lifestyle Factors
Smoking
Smoking damages blood vessels, increases blood pressure, and reduces oxygen supply to the heart muscle. These effects can weaken the heart and lower the ejection fraction over time.
Alcohol Abuse
Excessive alcohol consumption can lead to a condition known as alcoholic cardiomyopathy, where the heart muscle becomes weakened and enlarged. This reduces the heart’s ability to pump blood and can significantly lower the ejection fraction.
Sedentary Lifestyle
Lack of physical activity can contribute to obesity, high blood pressure, and diabetes, all of which can negatively impact heart function and lead to a lower ejection fraction.
Poor Diet
Diets high in saturated fats, trans fats, and cholesterol can contribute to the development of coronary artery disease and high blood pressure, which can weaken the heart and reduce its ejection fraction.
Infections and Inflammatory Conditions
Myocarditis is an inflammation of the heart muscle, often caused by viral infections. This condition can damage the heart muscle and impair its ability to pump blood, resulting in a lower ejection fraction.
Endocarditis
Endocarditis is an infection of the inner lining of the heart chambers and valves. This infection can damage heart valves and the heart muscle, leading to a decreased ejection fraction.
Pericarditis
Pericarditis is inflammation of the pericardium, the sac surrounding the heart. Severe or chronic pericarditis can lead to constrictive pericarditis, where the pericardium becomes thickened and rigid, restricting the heart’s ability to fill with blood and reducing the ejection fraction.
Medications and Treatments
Chemotherapy
Certain chemotherapy drugs used to treat cancer can have toxic effects on the heart muscle, leading to a condition known as cardiotoxicity. This can weaken the heart and lower the ejection fraction.
Radiation Therapy
Radiation therapy to the chest area, especially when treating cancers such as lymphoma or breast cancer, can damage the heart muscle and blood vessels, reducing the heart’s pumping efficiency and ejection fraction.
Drugs and Substance Abuse
The use of certain recreational drugs, such as cocaine and methamphetamine, can cause severe damage to the heart muscle, leading to cardiomyopathy and a decreased ejection fraction.
Genetic Factors
Inherited Cardiomyopathies
Some forms of cardiomyopathy are inherited and can lead to a lower ejection fraction. Genetic mutations can affect the structure and function of the heart muscle, predisposing individuals to heart failure and other cardiac conditions.
Familial Hypercholesterolemia
This genetic disorder leads to high levels of cholesterol in the blood, increasing the risk of coronary artery disease and myocardial infarction, which can ultimately result in a lower ejection fraction.
Conclusion
Low ejection fraction of the heart is a serious medical condition that can result from a variety of causes, including heart diseases, lifestyle factors, infections, and genetic predispositions. Understanding these causes is essential for the prevention, diagnosis, and treatment of heart failure and other related conditions.