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a) Pre-Ejection Period (PEP) – measured from beginning of QRS to opening of aortic valve. Corresponds to isovolumetric contraction (close association with dP/dt)
An accurate ejection fraction is no justification for the Teichholz formula in veterinary medicine. It's certainly true that the more measured information is included, the better chance there is for an accurate volume determination.
Ejection fraction is simple to calculate; if the left ventricle contains 100 ml of blood at the end of diastole and 40 ml is pumped out during systole, then the ejection fraction is 40%. Thus, the ejection fraction is the stroke volume (SV) divided by the end-diastolic volume (EDV):
Calculating an ejection fraction involves tracing around the endocardium of the left ventricle in diastole and systole. If your machine has a full cardiac package, it will then automatically calculate the ejection fraction (EF) for you using Simpson’s method of disks.
Machine will calculate Ejection fraction (will also display EDV and ESV – End diastolic volume and End systolic volume) Normal value – >50% in normal dog Decreased in DCM (heart contracting poorly during systole)
Ejection fraction (EF) reflects both cardiac function and remodeling, and is widely recognized as a valuable diagnostic and prognostic tool. Its use in a variety of settings, ranging from heart failure and myocardial infarction to valvular heart disease, has made it a cornerstone of modern cardiology, pervading guidelines and practice.
The ejection volume divided by the end-diastolic volume is the ejection fraction. The formula used is the Tiecholz formula which is based upon the spherical volume of the heart multiplied by a correction factor.
