hello by closed heart valve i beleive that one of your heart valves has become tight enough to slow the flow.what we call stenotic valve. such valve disease can get complications in which your valve gets infected.may be the chest infection you got few months back led to a similar major complication of the heart valve infection. such infections can become life threatening. apart from treating such infections wih antibiotics it is also important to know the source of such infections. the ct scan , endoscopy must have been planned to find the source of infection to prevent such life threatening situations. hope this helps