Normal range of myocardial layer-specific strain using two-dimensional speckle tracking echocardiography

Area of Science:

• Cardiology
• Medical Imaging
• Biomedical Engineering

Background:

• Layer-specific strain assessment using newer 2D software shows promise.
• Normal reference values for layer-specific strain are currently lacking.
• Establishing these values is crucial for accurate cardiovascular assessment.

Purpose of the Study:

• To establish normal reference ranges for layer-specific longitudinal and circumferential strain.
• To define normal values for endocardial, transmural, and epicardial global longitudinal strain (GLS) and global circumferential strain (GCS).
• To investigate the strain gradient across the myocardium using the endocardial to epicardial strain ratio (Endo/Epi).

Main Methods:

• Retrospective analysis of strain parameters in 235 healthy subjects.
• Utilized layer-specific 2D speckle tracking software.
• Measured endocardial, transmural, and epicardial GLS and GCS, along with the Endo/Epi ratio.

Main Results:

• Normal ranges for endocardial, transmural, and epicardial GLS were -23.1±2.3, -20.0±2.0, and -17.6±1.9, respectively.
• Normal ranges for endocardial, transmural, and epicardial GCS were -28.5±3.0, -20.8±2.3, and -15.3±2.0, respectively.
• Layer-specific strain showed gender dependency (except endocardial GCS) but no age dependency; however, basal/middle endocardial longitudinal strain decreased with age, while apical endocardial longitudinal strain was preserved.

Conclusions:

• Proposed normal reference values for layer-specific strain, stratified by age and gender.
• Detailed strain analysis offers layer-oriented insights.
• Potential to characterize various cardiovascular diseases based on layer-specific myocardial function.