WHEN GETTING EJECTED IS A GOOD THING
Ejection Fraction is a physiological calculation based on stroke volume and end diastolic volume that represents the efficiency of ventricular function. It examines how much blood was actually pumped out of the left ventricle (SV, stroke volume) compared to how much could potentially be pumped out (EDV, end diastolic volume).
The more blood pumped out, the greater cardiac efficiency is. Since efficiency means getting more for the same, getting more blood pumped for the same mechanical cycle of the heart, translates to greater cardiac efficiency. The same analysis can be done comparing the blood pumped out to the cardiac contractile force produced by thee ventricle walls.
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Accordingly, Ejection Fraction (EF, %) = (100 x Stroke Volume)/ End Diastolic Volume or
EF (%) = (100 x SV)/ EDV. Since Stroke Volume = (End Diastolic Volume - End Systolic Volume), it can be used interchangeably with SV in any equation that includes stroke volume (SV). Thus, Ejection Fraction (EF, %) = 100 x (EDV - ESV)/EDV.
Different ejection fraction values (%) correlate with different fitness and/or health levels and conditions. The higher the ejection fraction, the better. With that said, since EDV is always greater than SV, EF can never be 100%. In elite athletes or well-trained people (exercising yet not competing as athletes) EF can be as great as 90%, meaning that 90% of the blood that filled the left ventricle was pumped out.
If a person is trained (exercising), yet is not an elite athlete, their EF should range from 70% to 90%, depending on how trained they are. The more trained they are, the higher EF should be. The average person is untrained with an ejection fraction that ranges from 50% to 70%. People with an ejection fraction between 40% and 49% are considered at risk or high risk for Heart Failure (HF) and Chronic Heart Failure (CHF) if not treated or the causes are not addressed.
People with an ejection fraction of less than 39% meet the medical criteria to be diagnosed with Heart Failure (HF) or Chronic Heart Failure (CHF). In essence, any factor that negatively influences cardiac ventricular filling (the amount of blood in the ventricle) and cardiac contraction force will decrease ejection fraction and could possibly cause heart failure or chronic heart failure.
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