Introduction
Mitral stenosis (MS) is a cardiac disorder generally caused by Rheumatic Fever (RF) and characterized by morphological changes in the mitral valve such as commissural fusion, retraction, thickening and narrowing of the mitral valve apparatus and leaflets 1. Right Ventricular (RV) failure has a critical role in the onset and progression of clinical symptoms and the prognosis of MS patients, but the exact role, effect, and pathophysiology of RV dysfunction in MS is still controversial 2.. Some theories suggest that the pathophysiological and structural changes that are caused by MS lead to pulmonary hypertension (PH) and increased pulmonary artery pressure (PAP), which eventually result in RV dysfunction 3. It is still not known whether the degree of MS severity has a correlation with RV dysfunction independent of PH and high PAP.
Furthermore, echocardiographic markers are able to predict rehospitalization rates in MS patients4. Since a delayed diagnosis can result in high rates of morbidity and mortality, while early interventions have immensely improved clinical outcomes, early detection of RV dysfunction is critical for the patients5. Various imaging methods have been employed to evaluate RV function such as radionuclide angiography, contrast right ventriculography, and novel modalities like magnetic resonance imaging; however, most are confined by restrictions 6. Although cardiac imaging has remarkably improved in recent years, measuring the size and function of RV has remained a complex process due to the special crescent structure of the RV and morphological differences between the Left Ventricle (LV) and RV 7-9. Tissue Doppler imaging (TDI) is a simple, safe, cost-effective, and accurate modality for detecting both RV and LV dysfunction 10. Even though TDI enhanced the diagnostic yield of echocardiography, the reliability of its data is controversial due to its angle dependency11. Velocity Vector Imaging (VVI) is among the more novel and more reliable means of investigating LV and RV function using strain imaging, due to being angle-independent 12-16.
In order to assess the correlation of the degree of MS severity with RV dysfunction and to discover the echocardiographic markers that can be used as early diagnostic features of subclinical RV dysfunction, we aimed to investigate the echocardiographic signs of systolic RV dysfunction using TDI and VVI in patients with severe and very severe mitral stenosis.