The relation between mitral annulus motion and ejection fraction changes with age and heart size.

Area of Science:

• Cardiology
• Echocardiography
• Medical Imaging

Background:

• Mitral annulus motion (MAM) is a novel echocardiographic index for assessing left ventricular (LV) function.
• Previous studies suggested a conversion factor of 5 to relate MAM (mm) to ejection fraction (EF, %).
• These studies primarily included older patient cohorts (mean age > 60 years).

Purpose of the Study:

• To investigate the age-specific relationship between MAM and EF.
• To determine if the conversion factor from MAM to EF is constant across different age groups.
• To evaluate the influence of patient height and LV diameter on the EF/MAM ratio.

Main Methods:

• Echocardiographic assessment of 102 patients.
• Measurement of mitral annulus motion (MAM) and calculation of ejection fraction (EF).
• Analysis of the conversion factor (EF/MAM) across different age groups (20-40, 41-60, 61-80 years) and correlation with height and LV diameter.

Main Results:

• The conversion factor from MAM to EF significantly varies with age: approximately 4.3 for ages 20-40, 4.6 for 41-60, and 5.0 for 61-80 years.
• The ratio EF/MAM decreases with increasing patient height and left ventricular diameter.
• These findings indicate that heart size and age influence the relationship between MAM and EF.

Conclusions:

• The established conversion factor of 5 between MAM and EF is not universally applicable and is inaccurate in younger individuals.
• Using MAM as a direct index of ventricular function with age- and height-referenced values is preferable.
• If EF is reported, age-dependent conversion factors are necessary for accurate estimation from MAM.