Early Detection of Right Ventricular Dysfunction by Myocardial Performance Index in Diabetic Patients

Abstract

Introduction :Diabetes mellitus is one of the most common endocrine disorders. The incidence of diabetes mellitus is continuously increasing and about 90% of patients of diabetes mellitus have type 2 diabetes mellitus . 1 Reports from the Framingham study and other studies have established diabetes as a strong risk factor for cardiovascular morbidity and mortality. [2][3][4] Diabetes mellitus has direct effects on the heart, independent of obstructive disease and hypertension and causes development of a specific cardiomyopathy. 5 Several studies using echocardiography have demonstrated deterioration in left ventricular diastolic properties in diabetic patients. [6][7][8][9] RV function has proven to be of importance for risk stratification in heart failure and is associated with sudden death and exercise limitation . 10 RV function has not been studied in depth yet in diabetic patients although the RV has an important contribution to the overall cardiac function . 11 RV dysfunction especially diastolic dysfunction may play a role in diabetic cardiomyopathy. 10 The majority of proposed methods of echocardiographic assessment of RV function are based on volumetric approximations of RV .Such approaches have inherent limitations ,first as volume related measures such as ejection fraction (EF) are load dependant; second because of the complex geometry of RV . 12 The issue of RV geometry is usually overcome using geometry -independent parameters such as tricuspid annular velocity and MPI .MPI is calculated using Doppler as the ratio of the isovolumic contraction and relaxation times to the ejection time which encompasses both systolic and diastolic functions. 13 In systolic dysfunction ,the isovolumic contraction time increases ,whereas the ejection time decreases and ,consequently , the MPI increases. In diastolic dysfunction, there is prolongation of isovolumic relaxation time that also results in an increased MPI .Tei et al. 14 proposed a Tei index (or myocardial performance index ) ,obtained from Doppler time intervals, which allows simple noninvasive and nongeometric estimation of global ventricular functions. It has been found to have prognostic value for various cardiac conditions .Yeo et al. 15 reported Doppler right ventricular index to be a useful noninvasive parameter that correlates with symptoms and survival in patients with pulmonary hypertension .Data regarding RV performance in patients with diabetes are incomplete. Some studies have been shown right ventricular dysfunction. Myocardial dysfunction in patients with diabetes mellitus is not confined to the left ventricle, but also involves the right ventricle, and the impairment of RV function encompasses both systolic and diastolic abnormalities. Abstract:In diabetes mellitus (DM) patients, left ventricular dysfunction is widely evaluated and established by conventional diagnostic methods, whereas right ventricular (RV) function is not sufficiently evaluated. The aim of this study was to assess the right ventricular function in type 2 diabetic patients...