Normal ranges of left ventricular strain: a meta-analysis

Area of Science:

• Cardiology
• Medical Imaging
• Echocardiography

Background:

• Defining normal left ventricular strain values (GLS, GCS, GRS) is crucial for clinical applications.
• Significant variations exist in reported normal strain ranges.
• A meta-analysis was conducted to determine normal ranges and identify sources of variation.

Purpose of the Study:

• To perform a meta-analysis of normal ranges for left ventricular global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS).
• To identify factors contributing to the reported variations in normal strain values.

Main Methods:

• A systematic search of MEDLINE, Embase, and Cochrane Library databases was performed through August 2011.
• Included studies reported left ventricular strain using 2D speckle-tracking echocardiography in healthy subjects.
• A random-effects model was used for data combination, with meta-regression to assess influencing factors.

Main Results:

• The analysis included 2,597 subjects from 24 studies.
• Reported normal GLS ranged from -15.9% to -22.1%, GCS from -20.9% to -27.8%, and GRS from 35.1% to 59.0%.
• Significant heterogeneity was observed; systolic blood pressure was associated with variations in normal GLS values.

Conclusions:

• While GLS and GCS showed narrower confidence intervals, individual studies reported broad normal strain ranges.
• Variations in normal strain ranges appear linked to differences in systolic blood pressure.
• Systolic blood pressure should be considered when interpreting echocardiography-derived strain values.