STRAIN/STRAIN RATE ECHOCARDIOGRAPHY

The characterization of local myocardial deformation, for both local radial and longitudinal function, could be important in heart diseases. Strain and strain rate echocardiography derived tissue Doppler imaging is a new clinical approach to quantifying regional radial and longitudinal myocardial function. Strain is defined as the myocardial tissue deformation induced by the regional contraction and relaxation. Strain rate is defined as the instantaneous rate of change in two velocities divided by the instantaneous distance between the two points. These parameters are much less affected by passive myocardial motion and tend to be uniform throughout the left ventricle in normal subjects. Several groups of investigators have demonstrated the superiority of strain and strain rate over tissue Doppler velocity for tracking local myocardial function. This article revises strain/strain rate imaging technique and its utilization in clinical practice.