Pulsus and electrical alternans due to the presence of a mitral caged ball-valve prosthesis

Almost 2 years after a successful mitral valve replacement with a ball-valve prosthesis, a 54-year-old patient was found to have mechanical and electrical alternans. Evidence is presented to suggest that strong left ventricular contraction and, therefore, a small early diastolic chamber size can interfere with the functioning of the ball-valve and produce pulsus alternans. This is the first report of such a case.