Left-ventricular cavity dimensions in children with normal and dilated hearts

Area of Science:

• Cardiology
• Biomedical Engineering
• Pediatric Cardiology

Background:

• Understanding left-ventricular (LV) geometry is crucial for assessing cardiac function.
• Previous studies have explored LV dimensions but lacked comprehensive analysis across a wide age and body size range.
• The relationship between LV dimensions, body size, and dilation requires further elucidation.

Purpose of the Study:

• To investigate the relationship between left-ventricular length and length/diameter ratio with body size and the degree of cardiac dilation.
• To establish predictive formulas for LV dimensions based on body surface area (BSA) and echocardiographic measurements.
• To explore factors influencing the end-systolic length/diameter ratio.

Main Methods:

• Utilized M-mode and two-dimensional echocardiography to measure diastolic and systolic LV dimensions in subjects aged 2 to 23 years.
• Measured diastolic cavity long axis (Led), diastolic cavity diameter (Ded), systolic cavity long axis (Les), systolic cavity diameter (Des), fractional shortening (SFL), and fractional shortening (SFD).
• Analyzed correlations between LV dimensions, BSA (0.5-2.1 m2), and SFD values across various volume loads and pathologies.

Main Results:

• In normal subjects, the Led/Ded ratio was approximately 1.9.
• Led consistently correlated with BSA (Led = 3.9 + 3.2 BSA), showing minimal change with pathological dilation.
• Established linear relations for Led/Ded vs BSA/D2ed and end-systolic dimensions, including a formula relating end-systolic L/D ratio to end-diastolic L/D ratio and SFD.

Conclusions:

• LV length demonstrates a consistent correlation with BSA, suggesting relative stability during dilation.
• Developed quantitative relationships that can aid in the interpretation of echocardiographic images.
• LV length/diameter ratio may be influenced by myocardial anisotropy and external factors affecting LV shape.