Which valve is most commonly affected by infective endocarditis?

Infective endocarditis most commonly affects the aortic valve, particularly in individuals with pre-existing heart conditions or those with risk factors such as previous valvular disease or prosthetic heart valves. The aortic valve is subject to higher pressures due to its location between the left ventricle and the aorta, making it more vulnerable to damage and infection.

Additionally, in the context of intravenous drug use, the tricuspid valve becomes more commonly affected due to the direct delivery of pathogens into the bloodstream. However, for the general population and in the absence of specific risk factors, the aortic valve remains the most commonly involved site in infective endocarditis.

While the mitral valve is also a common site of infection, particularly in patients with rheumatic fever or degenerative valve disease, the aortic valve remains the leading candidate overall. The pulmonary valve is the least commonly affected due to the lower pressures and blood flow dynamics associated with the right heart compared to the left side. Understanding the prevalence and variety of affected valves enhances the clinical recognition and management of infective endocarditis.