Journey from two-dimensional to four-dimensional strain and left ventricle torsion in the evaluation of coronary artery disease

Abstract

The use of echocardiography in the diagnosis of suspected myocardial infarction has been classified as appropriate. The use of regional strain which is a dimensionless measurement of deformation, expressed as a fractional or percentage change from an object's original dimension, greatly enhances the accuracy of detecting the regional wall motion abnormality in a scale (-20 to +20) ten times that of eye balling. Speckle-tracking echocardiography (STE) is a novel technique which has emerged as one of the best methods that analyses motion and strain by tracking natural acoustic reflections and interference patterns within an ultrasonic window. In patients with acute myocardial infarctions (MIs), accuracy for the prediction of global functional improvement as well as LV remodelling by 2D STE is comparable with that of late gadolinium enhancement cardiac magnetic resonance (CMR) imaging. Global longitudinal strain (GLS) has evolved as one of the most robust parameter, and this has been shown to identify subclinical LV dysfunction.3D STE has emerged as an alternative non -invasive technique to assess LV rotation. In anterior wall myocardial infarction, systolic twist is decreased, and diastolic untwisting is depressed in accordance with LV systolic dysfunction. These results suggest the significant impact of global LV systolic function on LV twist and twist-displacement loops in patients with anterior wall MI. Although to date, no prognostic information exists on the role of rotational parameters of LV function, further ongoing studies would shed more light on this important technique.

Keywords

• coronary artery disease
• echocardiography
• four-dimensional strain