A new method for quantification of left ventricular systolic function using a corrected ejection fraction.

Area of Science:

• Cardiology
• Biomedical Engineering
• Mathematical Modeling

Background:

• Left ventricular ejection fraction (EF) is a standard but potentially suboptimal measure of systolic function.
• Increasing end-diastolic wall thickness can lead to an overestimation of ventricular function by EF.
• Concentric left ventricular hypertrophy (LVH) complicates the accurate assessment of systolic function using EF.

Purpose of the Study:

• To propose a new measure, the corrected ejection fraction (EF(c)), to account for left ventricular hypertrophy (LVH).
• To develop a method for more accurately assessing left ventricular systolic function in the presence of LVH.

Main Methods:

• Utilized a novel two-layer, three-dimensional mathematical model of ventricular contraction.
• Modeled changes in end-diastolic wall thickness, long-axis, and mid-wall circumferential strain.
• Developed iso-strain lines to visualize the relationship between strain and EF with varying wall thickness.

Main Results:

• Demonstrated that EF increases with increasing end-diastolic wall thickness when myocardial shortening (strain) is constant.
• Showed an example where a measured EF of 60% with 20 mm wall thickness corresponds to a corrected EF (EF(c)) of 37%.
• Provided a nomogram for comparing EF values in the presence of LVH.

Conclusions:

• The study highlights that EF is influenced by absolute wall thickening, not just myocardial shortening.
• The corrected EF (EF(c)) is proposed as a potentially more accurate index of left ventricular systolic function.
• Further validation of EF(c) in mortality trials is recommended.