- Concept of ejection fraction
- How to test the ejection fraction?
- Who is the ejection fraction rated for?
- Ejection fraction - correct values
- Practical importance of the ejection fraction
- Heart rate
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Ejection fraction (LVEF - left ventricle ejection fraction), or rather left ventricular ejection fraction, is the basic parameter assessed in echocardiography. It is the percentage of change in the volume of the left ventricle with the heartbeat. Find out what exactly is an ejection fraction and what its practical significance is.
Ejection fraction(EF - ejection fraction, LVEF - left ventricle ejection fraction) is the basic parameter assessed in cardiology, it tells about the efficiency of the heart and determines the percentage of blood that is ejected from the left ventricle during each contraction. Normal values are above 50%, and in most cases 60% is considered the norm.
The most important clinically is a decrease in the ejection fraction below 50% - it allows to diagnose heart failure with a reduced ejection fraction and below 35% - in this case, implantation of a cardioverter-defibrillator may be necessary. Thus, the assessment of the ejection fraction is crucial in most cardiological diseases - both for diagnostic purposes and for disease progress control and treatment planning.
Concept of ejection fraction
Ejection fraction is the ratio of stroke volume to end-diastolic volume. What exactly does this mean?
Ejection fraction is most often estimated by subtracting the end-systolic volume - the smallest left ventricular volume from the end-diastolic volume - its largest volume.
The result of this action is the volume of blood that has been pumped out of the chamber into the aorta. This volume is then divided by the end-diastolic volume (the largest volume of the ventricle). The obtained fraction is multiplied by 100%, so the ejection fraction is determined as a percentage.
In the vast majority of cases, the ejection fraction is determined for the left ventricle. It is theoretically possible to calculate it for the right ventricle, but it has no practical significance.
How to test the ejection fraction?
The basic test that allows for the assessment of the ejection fraction is a transthoracic echocardiography, i.e. heart ultrasound (USG). The examination is painless and harmless. There are many methods of estimating this parameter in the echo of the heart, including the method of Simpson or Teicholz. Some echocardiography machines also have an imaging functionin three dimensions, this way you can also calculate the ejection fraction.
Another test useful in the assessment of this parameter is cardiac magnetic resonance, but in the assessment of the ejection fraction it is performed very rarely due to the accuracy of the echocardiographic examination.
Ventriculography is an invasive test with the use of contrast agent. It consists in administering a contrast agent to the left ventricle and assessing its ejection by the heart. Due to the availability of non-invasive methods, ventriculography is currently practically not performed.
Who is the ejection fraction rated for?
The assessment of the ejection fraction allows for the diagnosis of e.g. heart failure, as well as for the assessment of changes in the heart caused by e.g. a previous infarction. There are many indications for the assessment of heart function, including:
- suspicion and evaluation of heart failure progression
- heart attack
- valvular disease
- perennial hypertension
The doctor - cardiologist decides about the indications for this examination.
It is obvious that the ejection fraction may change throughout life depending, among other things, on cardiovascular diseases or treatment.
Ejection fraction - correct values
It is not possible for the ejection fraction to be 100% as it is not possible for the hearts to pump out all the blood in the ventricles.
The correct values of the ejection fraction are not precisely defined, most often the result is 60% as correct.
The most important from a practical point of view isdecrease of the ejection fraction :
- values of 45-55% are referred to as a gentle reduction
- 30-45% - moderate reduction
- below 30% - heavy reduction
Due to the possibilities of cardiac imaging and the variety of echocardiography machines available, the value of the ejection fraction may vary by several percent between tests.
It is important to know that the result of the measurement of the ejection fraction depends, among others, on the heart rate, the presence of arrhythmia (e.g. atrial fibrillation), or hydration.
Practical importance of the ejection fraction
As mentioned earlier, the ejection fraction assesses the efficiency of the work performed by the heart, and thus the percentage of its efficiency. This indicator shows how much blood is pumped during each contraction of the heart. The practical importance of the ejection fraction is enormous.
It is one of the basic parameters assessed in cardiology that says a lot about the condition of the heart and its effectiveness.
ReductionThe ejection fraction indicates too weak and ineffective work of the heart, in such cases heart failure is diagnosed with a reduced ejection fraction. The very term "heart failure" defines the condition of the circulatory system and it is most often caused by another disease of the circulatory system:
- ischemic heart disease
- long-term hypertension
- valvular disease
- or with many other diseases
Therefore, a newly diagnosed decrease in the ejection fraction is often an indication for more detailed cardiological diagnostics in order to look for the cause of this condition.
The effect of the reduced ejection fraction is a reduction in the amount of oxygen and nutrients supplied to all tissues of the body. This results in long-lasting states:
- shortness of breath
and ineffective collection of blood from the venous system:
- edema, including pulmonary edema
If heart failure occurs suddenly it can cause:
- drop in blood pressure
- shock and life-threatening - usually from a heart attack
A slight decrease in the ejection fraction may be asymptomatic.
Regular assessment of the ejection fraction in people with cardiological diseases is very important - it allows to diagnose emerging heart failure and plan treatment.
In the case of a very large drop - below 35%, it may be necessary to implant a cardioverter-defibrillator, i.e. a special device that interrupts dangerous arrhythmias. It has been proven that such a low ejection fraction may be associated with the emergence of life-threatening arrhythmias.Worth knowing
During the relaxation of the heart muscle, the volume of the ventricles and atria increases, the atrioventricular valves open (with the aortic and pulmonary trunk closed) and blood flows passively into all chambers due to the pressure difference.
The atria contract, and as a result, the pressure rises in them, which leads to the filling of the ventricles with blood. The volume of the ventricles at this point is the largest, we call it the end-diastolic volume and it is approximately 120ml.
Then the heart contracts. It starts with a so-called isovolumentric contraction, which means that the pressure in the heart's ventricles increases, but the volume of blood there is constant. This is due to the closure of the pulmonary and aortic valves.
During isovolumentric contraction, the pressure in the ventricles exceeds that in the atria and the atrioventricular valves are closed:tricuspid and mitral. The muscle of the heart chambers continues to contract, leading to an increase in pressure inside them, when its value exceeds the pressure in the pulmonary trunk and aorta, their valves open and blood is ejected - this is the so-called isometric contraction (the pressure in the left ventricle is constant, but it decreases). its volume). The volume of blood thrown out is approximately 60ml.
After the contraction is over, the pressure in the ventricles begins to drop, as a result of which the valves of the aorta and the pulmonary trunk close to prevent the flow of blood from flowing back. During systole, blood is not completely emptied from the heart chambers - there is a small end-systolic volume, i.e. the amount of blood that is there just before the aortic and pulmonary valve closure - usually about 50 ml.
Then the ventricles relax - the pressure drops, the atrioventricular valves open and the chambers fill with blood again.About the authorBow. Maciej GrymuzaA graduate of the Faculty of Medicine at the Medical University of K. Marcinkowski in Poznań. He graduated from university with an over good result. Currently, he is a doctor in the field of cardiology and a doctoral student. He is particularly interested in invasive cardiology and implantable devices (stimulators).
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