<prompt> Most common hea valve involved in IV drug user is:Mitral valveAoic valvePulmonary valveTricuspid valve  <response>: Answer is D Tricuspid valve Most common hea valve involved in IV drug layers is tricuspid valve. In almost 50 of patients who have endocarditis associated with injection drug use, infection is limited to the tricuspid valve - Harrisons Endocarditis in drug abusers: most common age of patients affected - young malese most often source of infecting microorganisms is: skine most common agent is staphylococcus aureus most common valve involved is Tricuspid valve. tricuspid valve 50 aoic valve 25 mitral valve 20 multiple valves rest murmurs are frequently absent9 Cardiac murmurs are almost always present in infective endocarditis except in patients with: - early acute endocarditis intravenous drug abuse with tricuspid valve infection 