Deformation imaging (strain imaging) is an echocardiographic method for evaluating myocardial function that is also suitable for clinical use. There are two deformation imaging techniques: Tissue Doppler and 2D strain (speckle tracking). Deformation imaging allows the measurement of regional myocardial deformation in three dimensions. Longitudinal deformation (strain) measures longitudinal myocardial fiber contraction, and reflects subendocardial myocardial function, which is usually the first to deteriorate in patients with heart disease. Reduced longitudinal strain can reveal heart disease even when ejection fraction and cardiac contractility appear normal. Deformation imaging can be used for diagnosing ischemia, distinguishing between pathological and physiological hypertrophy, and early detection of heart disease in hypertension or diabetes. Global longitudinal strain (GLS) is an indicator of overall left ventricular systolic function, and correlates with the prognosis better than ejection fraction.