Pressures at an All-Time High | Circulation
Ejection Fraction: How Is It Measured?
Ejection fraction (EF) measures the amount of blood pumped out of your heart's lower chambers, or ventricles. It's the percentage of blood that leaves your ventricle when your heart contracts. The term usually refers to just the left ventricle.
Measuring your ejection fraction can help doctors figure out whether you have certain heart problems, especially one type of heart failure. Despite the scary-sounding name, heart failure doesn't mean your heart stops; it just means it can't pump as much blood as your body needs. Your ejection fraction will also help the doctor decide which treatments are best for you and whether your treatment is working.
Left Ventricular Ejection Fraction (LVEF)
Your left ventricle pumps blood that's been enriched with oxygen through your aorta to the rest of your body. The LVEF can show the extent of damage from a heart attack, long-term high blood pressure, left-sided heart failure, or chemotherapy.
Right Ventricular Ejection Fraction (RVEF)
Your right ventricle takes blood that's come back to your heart and pumps it into your lungs where it picks up oxygen. Your doctor will measure RVEF if you have right-sided heart failure, which is less common.
If your heart is healthy, your EF should be between 55% and 70%. Below 50% is a sign of a problem. Below 40% could indicate heart failure. (Photo Credit: Claus Lunau/Science Source)
There are a few ways your doctor can find out your EF percentage. You'll probably have one of these tests:
Your ejection fraction is a percentage. It's calculated by dividing the volume of blood pumped out of the ventricle each time your heat beats (called stroke volume, or SV), by the total amount of blood in the ventricle (called end-diastolic volume, or EDV). Then you multiply the result by 100.
The formula looks like this: EF = (SV/EDV) x 100.
Many doctors consider a normal ejection fraction to be 55%-75%. If yours is 50% or lower, it's a sign that your heart--usually your left ventricle--may not pump out enough blood.
There's a gray area when your EF is between 50% and 55%. Some experts call this borderline.
A normal EF doesn't always mean your heart is healthy. You could have heart failure with preserved ejection fraction (HFpEF). It happens when your heart muscle thickens to the point that the left ventricle holds less than the usual amount of blood. Even if that chamber pumps the way it should, it doesn't release as much oxygen-rich blood as your body needs.
HFpEF Causes
The health conditions that can lead to HFpEF include:
It's more common in women, smokers, and older people.
HFpEF Treatment
Medication options include diuretics and other medicines that lower your blood pressure.
If your doctor says your ejection fraction is too low, under 50%, it means there may be a problem with your heart.
With a low ejection fraction, you might have symptoms like:
A low ejection fraction could be a sign of a condition such as:
Medications can raise your ejection fraction and make you feel better. Your doctor may suggest:
You might also need to make lifestyle changes such as:
A device like an implantable biventricular pacemaker or cardiac defibrillator can help your heart work better. It may also help some people who have a low EF live longer.
What to ask your doctorTake an active role in your health, especially if you have a low EF. Keep up with your appointments. Have your doctor explain your condition and treatment options. Here's a list of questions you may want to ask:
If your ejection fraction is higher than 75%, it could be a sign of a condition called hypertrophic cardiomyopathy. It causes the walls of your heart to beat harder. They become thick and stiff, and your heart doesn't take in or pump out as much blood as usual.
Can ejection fraction improve in 3 months?
Yes. If you get treatment, like medication and exercise, for the problem that's causing your injection fraction to be low, you can see improvement within 3 months.
What is the lowest ejection fraction you can live with?
According to experts, you can survive if your ejection fraction is as low as 5%. But your life expectancy at that point is quite low.
How serious is a 25 ejection fraction?
It's very serious. With an EF of 25% or lower, your heart function is considered seriously impaired.
Two Common Biomarkers Predict Heart Risk In Asymptomatic Childhood Cancer Survivors
image:
First and corresponding author Matthew Ehrhardt, MD, MS, St. Jude Department of Oncology
view moreCredit: St. Jude Children's Research Hospital
(MEMPHIS, Tenn. – January 11, 2024) Data from the St. Jude lifetime cohort study (St. Jude LIFE) revealed that two common biomarkers of cardiac function and damage could better predict cardiomyopathy within five years than routine clinical evaluations in high-risk, asymptomatic childhood cancer survivors. Early detection through screening using these two biomarkers may lead to earlier treatment to prevent and protect against further heart damage. The findings were published today in the Journal of Clinical Oncology.
Cardiomyopathy is often asymptomatic at onset and thus "invisible" to routine clinical evaluations. St. Jude Children's Research Hospital scientists found that two common biomarkers, global longitudinal strain (GLS) and N-terminal-pro-B-type natriuretic peptide (NT-proBNP), could identify survivors with otherwise normal appearing heart function who are at elevated risk of decline in heart muscle function.
"This may be a much more sensitive way to identify childhood cancer survivors that might benefit from intervention at an earlier stage," said first and corresponding author Matthew Ehrhardt, MD, MS, St. Jude Department of Oncology. "We were somewhat surprised by the magnitude of risk for declining heart function over such a relatively short period in individuals with abnormal GLS and NT-proBNP, suggesting a need for early and effective interventions that we hope will prevent progression to heart failure over time."
The results showed an increase in predicting asymptomatic heart damage in patients treated with potent anthracycline chemotherapy drugs, such as doxorubicin. The study found that these biomarkers did not improve prediction models in patients who only received radiation. This knowledge may help physicians limit testing to only anthracycline-exposed survivors, saving time and resources while maximizing utility.
"This means doing more for patients at greatest risk while avoiding unnecessary tests for patients who will not benefit from them," Ehrhardt said.
Two signs point to invisible heart problems
The key to helping survivors with asymptomatic cardiomyopathy is to detect dysfunction early. Cardiac function is typically assessed using echocardiograms, which look at the volume of blood pumped through part of the heart. The most common measure of that volume is called left ventricular ejection fraction. Many childhood cancer survivors appear to have a normal ejection fraction, only to later develop cardiomyopathy. Findings showed that even in survivors with normal ejection fraction, abnormal GLS and NT-proBNP improved the ability to predict cardiomyopathy risk.
"A survivor with a normal ejection fraction at baseline with abnormal ranges of both biomarkers was at a fourfold increased risk for a worsening ejection fraction in the next five years," Ehrhardt said.
GLS is an additional measure of heart function obtained from an echocardiogram. GLS is more sensitive for detecting cardiac muscle injury than the traditionally reported ejection fraction. It is a software-derived mathematical estimation of the heart muscle fibers' ability to contract, rather than the more rudimentary measure of ejection fraction, or blood volume pumped at a specific time. An institution that performs echocardiograms to measure ejection fraction can theoretically also routinely measure GLS.
NT-proBNP is a serum biomarker, a chemical released into the bloodstream in greater quantities when the heart is injured or overworked. It is frequently used in adult cardiac patients to identify potential heart injury and is thus widely available, though its application in pediatric oncology is relatively novel.
Practical measures to predict and protect the heart earlier
"One of the promising aspects of our findings is that both of these measures are readily available and, therefore, have the potential to impact care more immediately. Most cardiologists are already using GLS," Ehrhardt said, "and NT-proBNP has been around for a long time."
Together, these two common and easy-to-implement measures may help identify survivors at elevated risk of cardiomyopathy earlier, leading to earlier therapeutic interventions. Early detection helps protect against cardiac damage in adults with other diseases; it may extend the same benefits to childhood cancer survivors.
"The exciting part of this study is that it potentially helps to identify a population that we would have otherwise looked at and said, 'You're at risk for abnormal heart function, but everything looks good today. We'll reevaluate your heart in two to five years,'" Ehrhardt said. "Whereas now we have reason to believe those with abnormal biomarkers are a particularly high-risk group that may benefit from closer follow-up or more proactive interventions to reduce risk. The findings set the stage for future studies evaluating novel screening and early intervention strategies that we hope will ultimately improve survivors' cardiac health and well-being."
Authors and funding
The study's other authors are Qi Liu, University of Alberta; Isaac B. Rhea, University of Tennessee Health Science Center; Daniel Mulrooney, Stephanie Dixon, John Lucas, Yadav Sapkota, Kyla Shelton, Kirsten Ness, Deo Kumar Srivastava, Aaron McDonald, Leslie Robison, Melissa Hudson, Yutaka Yasui and Gregory Armstrong, of St. Jude.
The study was supported by grants from the National Cancer Institute (Cancer Center Support (CORE) grant (P30CA21765), U01CA195547 and R01CA216354) and ALSAC, the fundraising and awareness organization of St. Jude.
St. Jude Media Relations Contacts
Chelsea Bryant
Cell: (256) 244-2048
Desk: (901) 595-0564
chelsea.Bryant@stjude.Org
media@stjude.Org
Rae Lyn Hartley
Cell: (901) 686-2597
raelyn.Hartley@stjude.Org
media@stjude.Org
St. Jude Children's Research Hospital
St. Jude Children's Research Hospital is leading the way the world understands, treats and cures childhood cancer, sickle cell disease and other life-threatening disorders. It is the only National Cancer Institute-designated Comprehensive Cancer Center devoted solely to children. Treatments developed at St. Jude have helped push the overall childhood cancer survival rate from 20% to 80% since the hospital opened more than 60 years ago. St. Jude shares the breakthroughs it makes to help doctors and researchers at local hospitals and cancer centers around the world improve the quality of treatment and care for even more children. To learn more, visit stjude.Org, read St. Jude Progress blog, and follow St. Jude on social media at @stjuderesearch.
JournalJournal of Clinical Oncology
Article Publication Date11-Jan-2024
Disclaimer: AAAS and EurekAlert! Are not responsible for the accuracy of news releases posted to EurekAlert! By contributing institutions or for the use of any information through the EurekAlert system.
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