Left Ventricular Strain in Systemic Diseases

Systemic diseases consist of various pathological conditions with a wide range of symptoms, often with progressive clinical worsening. Cardiac involvement is not uncommon in many of these conditions. Subclinical myocardial dysfunction is the common manifestation during the early stages of the disease and recognition of early myocardial dysfunction is very important for diagnosis and future prognosis. Left ventricular ejection fraction (LVEF) is considered less sensitive to detect early LV myocardial dysfunction. Strain imaging, performed using speckle-tracking echocardiography (STE), has emerged as a robust tool for detecting early subclinical myocardial dysfunction. The longitudinal muscle fibres are predominantly found in the sub-endocardium and are more susceptible to damage since the sub-endocardium is comparatively less perfused. Hence, longitudinal strain is impaired early in the course of the disease and helps in detecting subtle cardiac involvement in various systemic diseases. Global longitudinal strain, which is the average longitudinal strain of all the LV myocardial segments, is currently the most useful strain parameter for this purpose.