By Steven Schiff, MD, as told to Stephanie Booth
My patients’ concerns about heart failure are usually, “What’s my prognosis?” “What treatments, such as drugs and surgery, are available to me? But some people will ask me for their ejection fraction (EF) number if they’ve read about it or discussed it with them. This is especially true if they want to know if it changes over time.
What is EF?
EF is one of many measures of how well your heart is working. It measures your heart’s active pump function as it contracts and pumps blood out of your heart and into your arteries.
Technically, EF is the percentage (fraction) of blood that is ejected from your heart when it contracts. (This is also known as stroke volume).
Mathematically, EF is the amount of blood pumped with each beat, divided by the amount of blood in the chamber when it is full.
Your heart has two phases for each heartbeat:
- A filling phase (diastole)
- A phase of contraction or emptying (systole)
Therefore, EF is the trait [contracted] volume/diastolic volume.
What does EF have to do with heart failure?
A weak the ejection fraction lets the doctor know that the active pumping phase of the heart is not working. It is usually linked to some types of heart failure, but not all.
Heart failure with a low EF is called “systolic” heart failure.
How is EF measured?
EF is usually measured, with an echocardiogram or cardiac ultrasound. It can also be measured during cardiac angiography and catheterization. This is when catheters (tubes) are placed inside you through an artery, into your heart chambers.
Other measurement techniques include:
- Cardiac MRI
- Cardiac nuclear scans
- Cardiac scans
All of these techniques are estimates and may show slightly different results in the same person.
What do EF numbers mean?
Normal EF is between 55% and 70%. As the percentage decreases, this tells the doctor that the heart failure is getting worse. In general, if the EF falls below 30%, it is relatively serious. A reading of 20% or less is very serious heart failure.
It is important to know that there is not always a perfect correlation between symptoms and EF. In addition, an EF above 75% is considered too high and can also be a problem.
How can your EF help you manage your heart health?
Your EF can be a way to assess the status and progression of heart failure over time, as well as a way to track the benefits of various heart failure treatments.
For example, you may be told your EF, then start taking medication or having surgery, and you may want to know, “Has my EF increased or decreased?” We can follow serial EF measurements (usually by echocardiogram) to see if your treatment is helping you.
How can you have normal EF and heart failure?
Heart failure with normal EF is occurring more and more often. It is usually related to the filling phase of the core filling and emptying cycle. This is called “diastolic heart failure”.
Normal hearts are very compliant. This means they fill easily, at relatively low pressures. Sometimes, even though the heart is contracting normally (normal EF), it may need higher pressure to fill with each beat.
If so, you may have symptoms of heart failure even though your heart is contracting normally, with a normal EF. You could have fluid buildup and overload. We see it most often in people with untreated high blood pressure.
Should you know your EF?
Most people without heart problems do not need to know their EF.
If you’re just worried about it, ask your doctor if you should be worried. A simple echocardiogram will provide a good estimate.
The most important thing to know, if you have been told about heart failure, is what the underlying cause is. This will affect your prognosis, treatment, tests and follow-up.
Among the most common causes [of heart failure] are:
- coronary artery disease
- heart attacks
- High blood pressure
- Heart valve problems
Once you have been diagnosed with heart failure, you should be seen by a cardiologist for a careful review of your underlying causes, the status of your heart failure, your current treatment, follow-up and prognosis. .