Left ventricular ejection fraction

Left Ventricular Ejection Fraction

Theleft ventricular ejection fraction (LVEF) is a measurement, expressed as a percentage, of how much blood the left ventricle pumps out with each contraction. It is a key indicator of heart function and is used to diagnose and monitor heart failure and other cardiac conditions.

Physiology

The heart is a muscular organ that pumps blood throughout the body. The left ventricle is the main pumping chamber of the heart, responsible for delivering oxygen-rich blood to the systemic circulation. During each heartbeat, the left ventricle contracts and ejects blood into the aorta. The ejection fraction is calculated by dividing the stroke volume (the amount of blood pumped out of the ventricle with each beat) by the end-diastolic volume (the total amount of blood in the ventricle before contraction) and multiplying by 100 to get a percentage.

Normal and Abnormal Values

A normal LVEF ranges from 55% to 70%. An LVEF below 55% may indicate heart dysfunction, while an LVEF below 40% is often associated with heart failure. An LVEF above 70% can also be abnormal, potentially indicating hypertrophic cardiomyopathy or other conditions.

Clinical Significance

LVEF is a critical parameter in the assessment of cardiac function. It is used to:

• Diagnose heart failure and determine its severity.
• Guide treatment decisions, such as the use of medications like beta-blockers and ACE inhibitors.
• Monitor the effectiveness of treatment in patients with heart failure or after a myocardial infarction.
• Assess the risk of complications in patients undergoing surgery.

Measurement Techniques

LVEF can be measured using several imaging techniques, including:

• Echocardiography: The most common method, using ultrasound waves to create images of the heart.
• Magnetic Resonance Imaging (MRI): Provides detailed images and is useful in certain clinical situations.
• Nuclear Medicine Scans: Such as the MUGA scan, which uses radioactive tracers to evaluate heart function.
• Cardiac Catheterization: An invasive procedure that can provide precise measurements.

Factors Affecting LVEF

Several factors can influence LVEF, including:

• Heart Rate: Tachycardia or bradycardia can affect the measurement.
• Blood Pressure: Hypertension or hypotension can alter cardiac output.
• Valvular Heart Disease: Conditions like aortic stenosis or mitral regurgitation can impact LVEF.
• Myocardial Infarction: Damage to the heart muscle can reduce LVEF.

Also see

• Heart failure
• Echocardiography
• Cardiac output
• Myocardial infarction
• Hypertrophic cardiomyopathy

Cardiovascular disease A-Z

Most common cardiac diseases

• Cardiac arrhythmia‎
• Cardiogenetic disorders‎
• Cardiomegaly‎
• Cardiomyopathy‎
• Cardiopulmonary resuscitation‎
• Chronic rheumatic heart diseases‎
• Congenital heart defects‎
• Heart neoplasia‎
• Ischemic heart diseases‎
• Pericardial disorders
• Syndromes affecting the heart‎
• Valvular heart disease‎

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A

• Accelerated idioventricular rhythm
• Acute decompensated heart failure
• Arteriosclerotic heart disease
• Athletic heart syndrome
• Atrial flutter
• Atrioventricular fistula
• Cardiovascular disease in Australia
• Autoimmune heart disease

B

• Brown atrophy of the heart

C

• Ebb Cade
• Cardiac allograft vasculopathy
• Cardiac amyloidosis
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D

• Duke Treadmill Score
• Duroziez's disease

E

• Eisenmenger's syndrome
• Embryocardia
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• Eosinophilic myocarditis

H

• Heart attack
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• Heart to Heart (1949 film)
• High-output heart failure
• Hyperdynamic precordium

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I

• Idiopathic giant-cell myocarditis
• Interventricular dyssynchrony
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• Isolated atrial amyloidosis

K

• Keshan disease

L

• Loeffler endocarditis

M

• Mydicar
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N

• Nonbacterial thrombotic endocarditis

O

• OLR1
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P

• Papillary fibroelastoma
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• Pulmonary vein stenosis

R

• Right axis deviation
• Roemheld syndrome

S

• Saturated fat and cardiovascular disease
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T

• Traumatic cardiac arrest

V

• Ventricular aneurysm
• Vibroacoustic disease
• Viral cardiomyopathy

W

• Waon therapy