From the Guidelines
Ejection fraction cannot be measured on an ECG (electrocardiogram). ECGs only record the electrical activity of the heart and cannot directly assess cardiac function or blood flow. To measure ejection fraction, which is the percentage of blood that leaves the left ventricle when it contracts, imaging studies are required. The most common tests used to measure ejection fraction are echocardiograms (ultrasound of the heart), cardiac MRI, nuclear stress tests, or cardiac catheterization. An echocardiogram is typically the first-line test due to its non-invasive nature, wide availability, and absence of radiation. If you need to assess a patient's ejection fraction, you should order an echocardiogram rather than relying on ECG findings. While ECGs can show evidence of prior heart attacks or electrical abnormalities that might suggest heart dysfunction, they cannot quantify ejection fraction or directly measure the heart's pumping ability. Understanding this distinction is important for proper cardiac assessment and management of patients with suspected heart failure or other cardiac conditions, as highlighted in the 2022 AHA/ACC/HFSA guideline for the management of heart failure 1.
Key Points to Consider
- ECGs are limited to assessing electrical activity and cannot measure ejection fraction directly 2.
- Imaging studies such as echocardiograms, cardiac MRI, and nuclear stress tests are necessary for measuring ejection fraction 1.
- The choice of imaging study may depend on the patient's specific condition, availability, and the need for additional information such as valvular function or cardiac structure 2.
- The most recent guideline from 2022 emphasizes the importance of accurately measuring ejection fraction for the classification and management of heart failure 1.
Clinical Implications
- Clinicians should not rely solely on ECG findings to assess cardiac function or diagnose heart failure 3.
- Ordering an appropriate imaging study is crucial for accurate diagnosis and management of patients with suspected heart failure or other cardiac conditions 1.
- Understanding the limitations of ECGs and the importance of imaging studies can improve patient outcomes by ensuring timely and appropriate interventions 1.
From the Research
Ejection Fraction on ECG
- Ejection fraction is a measurement of the heart's ability to pump blood, and it is typically measured using echocardiography, not electrocardiography (ECG) 4.
- A reduced ejection fraction, typically defined as an ejection fraction of 40% or less, is a characteristic of heart failure with reduced ejection fraction (HFrEF) 4, 5.
- HFrEF is a clinical syndrome characterized by dyspnea or exertional limitation due to impairment of ventricular filling or ejection of blood or both, and it is often accompanied by progressive left ventricular dilatation and adverse cardiac remodeling 4.
- The diagnosis of HFrEF typically involves a combination of medical history, physical examination, elevated natriuretic peptides, and identification of left ventricular systolic dysfunction with an ejection fraction of 40% or less as measured by echocardiography 4.
Treatment of Heart Failure with Reduced Ejection Fraction
- The treatment of HFrEF typically involves a combination of pharmacological and device therapies, including diuretics, beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor-neprilysin inhibitors, and mineralocorticoid receptor antagonists 4, 5.
- Recent developments in the treatment of HFrEF include the use of sodium-glucose cotransporter 2 (SGLT2) inhibitors, vericiguat, and transcatheter mitral valve repair, which have been shown to improve disease outcomes and reduce mortality 4, 5.
- The management of HFrEF should be individualized, and patients should be treated with a combination of therapies that are tailored to their specific needs and circumstances 5, 6.
ECG and Ejection Fraction
- While ECG is not typically used to measure ejection fraction, it can be used to diagnose other conditions that may be related to HFrEF, such as arrhythmias or conduction abnormalities 4.
- Echocardiography is the preferred method for measuring ejection fraction, as it provides a direct measurement of the heart's pumping function 4.