Mechanical valves: a silent worry

Mr KD is a 63-year-old schoolteacher who sees you regularly to monitor his warfarin therapy and cardiovascular risk profile. He takes warfarin for atrial fibrillation (AF) and the mechanical mitral valve replacement that he received 25 years ago for rheumatic mitral stenosis, with a target INR of between 2.5 and 3.5. He takes regular metoprolol for heart rate control, which was shown to be adequate on Holter monitoring a few years ago. He is overweight and has hypertension, as well as a family history of premature coronary artery disease. He has no other medical problems. He is married with three adult children and enjoys playing cards at his bridge club.

Today, Mr KD asks to see you because he has developed breathlessness on exertion. He first noticed this two months ago. The breathlessness occurs on mild to moderate exertion outside the house (corresponding to NYHA Class II symptoms). He denies experiencing chest pain, orthopnoea, leg swelling or palpitations. There is also no sputum production, fever or rigors. He is not usually an anxious person but reports being worried about his heart valve. In particular, one of his bridge partners noticed that the valve has fallen silent, having lost its regular ‘click’. Mr KD cannot recall this happening before and thought it should be checked.

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