Most common heart valve involved in IV drug user is –
**Core Concept**
The question is testing knowledge about the clinical consequences of intravenous (IV) drug abuse, specifically the involvement of heart valves in infective endocarditis. Infective endocarditis is a serious infection of the heart valves, often caused by bacterial or fungal organisms.
**Why the Correct Answer is Right**
Infective endocarditis is a well-known complication of IV drug abuse. The most common heart valve involved is the tricuspid valve, due to the direct injection of drugs into the veins, which can lead to bacterial seeding and colonization of the valve. The tricuspid valve is more susceptible to infection because of its proximity to the venous system and the high pressure of blood flowing through it.
**Why Each Wrong Option is Incorrect**
* **Option A:** The mitral valve is not the most common valve involved in IV drug users. While it can be affected, the tricuspid valve is more commonly involved due to the mechanism of infection.
* **Option B:** The aortic valve is not the most common valve involved in IV drug users. Although it can be affected, the tricuspid valve is more susceptible to infection due to its proximity to the venous system.
* **Option C:** The pulmonary valve is not typically involved in IV drug users. The tricuspid valve is more commonly affected due to the direct injection of drugs into the veins.
**Clinical Pearl / High-Yield Fact**
In IV drug users, the tricuspid valve is the most common valve involved in infective endocarditis, often leading to right-sided heart failure and other complications. This is a classic exam trap, as the mitral valve is often the valve of choice in other scenarios.
**Correct Answer: D. Tricuspid valve.**