Use of myocardial strain to assess global left ventricular function: a comparison with cardiac magnetic resonance and 3-dimensional echocardiography.
BACKGROUND
Ejection fraction (EF) plays a prominent role in clinical decision making but remains dependent on image quality and left ventricular geometry. Using magnetic resonance imaging (MRI-EF) as the reference standard, we sought whether global longitudinal strain (GLS) could be an alternative to the measurement of EF.


METHODS
Manual and semi-automated tracing was used to measure Simpson's biplane ejection-fraction (2D-EF) and 3D ejection fraction (3D-EF) and MRI in 62 patients with previous infarction. Global longitudinal strain was measured by 2-dimensional strain (2DS) in the apical views. Automated EF was calculated using speckle tracking to detect the end-diastolic and end-systolic endocardial border.


RESULTS
Strain curves were derived in all segments, with artifactual curves being excluded. The correlation of GLS with MRI-EF (r = -0.69, P < .0001) was comparable to that between 3D-EF and MRI (r = 0.80, P < .0001), and better than that between 2D-EF (r = 0.58, P < .0001) or automated EF and MRI (r = 0.62, P < .0001). To convert GLS into an equivalent MRI-EF, linear regression was used to develop the formula EF = -4.35 (strain + 3.9). Of the 32 patients with a normal MRI-EF (> or =50%), 75% had normal systolic function by GLS, whereas 85% of patients were recognized as having a normal 3D-EF. Fewer patients were recognized as normal by 2D-EF (70%, P = .14) and automated-EF (61%, P = .04). In those with >6 abnormal segments, the correlation of GLS with MRI-EF improved significantly (r = -0.77, P < .0001) and was similar to 3D-EF (r = 0.76, P < .0001).


CONCLUSIONS
Global longitudinal strain is an effective method for quantifying global left ventricular function, particularly in patients with extensive wall motion abnormalities.
Brown
Joseph
J
University of Queensland, Brisbane, Queensland, Australia.
Jenkins
Carly
C
Marwick
Thomas H
TH
D000368:Aged; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology; D013318:Stroke Volume; D016277:Ventricular Function, Left / Q000502:physiology*