Subjects
This cross-sectional study was performed on 46 patients with isolated MS and 23 healthy controls (matched by sex and age) at the Echocardiography Center of Qaem Hospital, Mashhad, Iran. Patients who had a history of more-than-moderate mitral insufficiency, LV failure, Ejection Fraction (EF) of <50%, valvular surgery, stenosis or insufficiency in other cardiac valves, were not included in the study. Additionally, patients with a history of atrial fibrillation (AF), underlying respiratory disease, coronary artery disease (CAD), or smoking were excluded before the start of the study. According to the latest guideline (at the time of the study) for the management of patients with valvular heart disease, patients were categorized into two groups of 23 severe (mitral valve area (MVA) between 1-1.5 cm) and 23 very severe MS subjects (MVA ≤1.0 cm) 2.