See below. A heart valve infection or endocarditis is usually caused by a bacterial infection of the valve. There are also not infectious causes of endocarditis. A normal CBC means that the complete blood count ie. Red blood cells, white blood cells and platelets are all normal. This is unusual in bacterial endocarditis but does occur.
Not much. Valvular endocarditis is an infection needing systemic antibiotics and possible surgery. A normal CBC does not have any relationship to the infection. It may be normal or high WBC or low wbc. There may be anemia or not. Same with platelets. If there is an abnormality of CBC with onset of endocarditis a normal CBC may reflect the pt is responding to treatment.