A child develops carditis from rheumatic fever. Which areas of the heart are affected by carditis?

Choice A reason: Rheumatic carditis primarily affects the mitral valve and myocardium, not aortic and pulmonic valves, which are less commonly involved. Inflammation targets endocardium and myocardium, making this incorrect, as it does not accurately reflect the primary cardiac structures affected in rheumatic fever. Choice B reason: Rheumatic fever carditis causes inflammation of the heart muscle (myocardium) and mitral valve, leading to myocarditis and valvulitis, often causing mitral regurgitation. This is the correct choice, as these are the primary areas affected, contributing to long-term complications like rheumatic heart disease. Choice C reason: Contractility of the ventricles may be indirectly affected by myocarditis, but carditis primarily involves the myocardium and mitral valve. Focusing on contractility alone is too narrow, making this incorrect, as it does not fully capture the structures targeted in rheumatic carditis. Choice D reason: Coronary arteries are not primarily affected in rheumatic carditis, which targets the myocardium and mitral valve. Coronary involvement is rare and not characteristic, making this incorrect, as the nurse should recognize the heart muscle and mitral valve as the primary areas.