Answer :
Final answer:
The mitral valve area is estimated using the formula "220 ÷ pressure half-time." This method is important for diagnosing conditions like mitral stenosis. The ejection fraction, also a key cardiac metric, is calculated by dividing stroke volume by end-diastolic volume.
Explanation:
To determining the area of the mitral valve using the Doppler echocardiography technique. The correct formula to calculate the mitral valve area is: A. 220 ÷ pressure half-time.
Pressure half-time (PHT) refers to the time it takes for the pressure gradient across the mitral valve to reduce to half its maximum value after the onset of diastole. The standard number 220 in the formula comes from empirical data and provides a simplified method of estimating mitral valve area, which is important for diagnosing and managing conditions such as mitral stenosis.
The ejection fraction is another important cardiac measure, expressed as a percentage, that indicates the volume of blood pumped out of the heart's left ventricle with each contraction. To calculate ejection fraction, stroke volume (SV) is divided by end-diastolic volume (EDV), and a normal range is typically between 55-70 percent.