Normal Values
Measure
|
Typical value | Normal range |
|---|---|---|
| end-diastolic volume (EDV) | 120 mL | 65–240 mL |
| end-systolic volume (ESV) | 50 mL | 16–143 mL |
| stroke volume (SV) | 70 mL | 55–100 mL |
| ejection fraction (Ef) | 58% | 55–70% |
| heart rate (HR) | 75 bpm | 60–100 bpm |
| cardiac output (CO) | 5.25 L/minute | 4.0–8.0 L/min |
In a healthy 70-kg (154-lb) man, the SV is approximately 70 ml and the left ventricular EDV is 120 ml, giving an ejection fraction of 70/120, or 0.58 (58%).
Right ventricular volumes being roughly equal to those of the left ventricle, the ejection fraction of the right ventricle is normally equal to that of the left ventricle within narrow limits.
Healthy individuals typically have ejection fractions between 50% and 65%. However, normal values depend upon the modality being used to calculate the ejection fraction, and some sources consider an ejection fraction of 55-75% to be normal. Damage to the muscle of the heart (myocardium), such as that sustained during myocardial infarction or in atrial fibrillation or a plurality of etiologies of cardiomyopathy, compromises the heart's ability to perform as an efficient pump (ejecting blood) and therefore reduces ejection fraction. This reduction in the ejection fraction can manifest itself clinically as heart failure. A low ejection fraction has its cutoff below 40% with symptomatic manifestations constant at 25%. In the USA, a chronically low ejection fraction less than 30% is qualifying support for eligibility of disability benefits from the Social Security Administration.
Healthy older adults favorably adapt as the ventricles become less compliant and are routinely echocardiographically proven to have an EF from 55-85% with the help of good genetics and a healthy lifestyle. Compliance changevolume /changepressure is a property of the heart that allows Contractility. Encyclopedic documentation of the commonly documented "Hyperdynamic" ventricle remains sparse.
The ejection fraction is one of the most important predictors of prognosis; those with significantly reduced ejection fractions typically have poorer prognoses. However, recent studies have indicated that a preserved ejection fraction does not mean freedom from risk.
The QT interval as recorded on a standard electrocardiogram or "EKG" represents ventricular depolarazation and ventricular repolarazation and is rate dependent.
Read more about this topic: Injection Fraction
Famous quotes containing the words normal and/or values:
“Normality highly values its normal man. It educates children to lose themselves and to become absurd, and thus to be normal. Normal men have killed perhaps 100,000,000 of their fellow normal men in the last fifty years.”
—R.D. (Ronald David)
“Parents ought, through their own behavior and the values by which they live, to provide direction for their children. But they need to rid themselves of the idea that there are surefire methods which, when well applied, will produce certain predictable results. Whatever we do with and for our children ought to flow from our understanding of and our feelings for the particular situation and the relation we wish to exist between us and our child.”
—Bruno Bettelheim (20th century)