Some patients with a failing heart can experience tingling
of the extremities, and you are at increased risk given your complex congenital heart history and current mitral valve regurgitation; my advise would be to visit again your pediatric cardiologist and probably repeat an echocardiogram to see the severity of the "leak" and the function of the ventricle; sometimes, if we suspect that the leak is worse than it looks, we suggest a transesophageal echocardiogram
which can give better images of the mitral valve.
Dr Brenes-Salazar MD
Mayo Clinic MN