Dexmeditomedine for mitral valve replacement

This study is testing a medication called dexmedetomidine to see if it can safely and effectively control heart rate in patients with severe mitral stenosis — a condition where the heart's mitral valve has narrowed significantly — before they undergo valve replacement surgery. Controlling heart rate during this time is important because it helps the heart pump blood more efficiently before the surgeon repairs the valve. You may be eligible if: - You are between 18 and 60 years old - You have been diagnosed with tight (severe) mitral stenosis with a valve area less than 1 cm - You are scheduled for mitral valve replacement surgery - You are classified as low-to-moderate surgical risk (ASA I or II) You may NOT be eligible if: - You are under 18 or over 60 years old - Your mitral valve area is greater than 1 cm - You have kidney or liver problems - You take heart medications that affect heart rate Talk to your doctor about whether this trial might be right for you.