Final answer:
An incompetent tricuspid valve leads to reduced efficiency in blood delivery to the lungs, as it causes tricuspid regurgitation, with the backflow of blood into the right atrium during ventricular contraction.
Step-by-step explanation:
An incompetent tricuspid valve would directly cause reduced efficiency in the delivery of blood to the lungs. The tricuspid valve is located between the right atrium and the right ventricle of the heart. Its main function is to prevent the backflow of blood when the right ventricle contracts, pushing blood towards the lungs for oxygenation through the pulmonary valve. If the tricuspid valve is incompetent or fails to close properly, it can lead to tricuspid regurgitation. This means that some blood would flow backward into the right atrium each time the right ventricle contracts, instead of all of it moving on to the lungs. This backflow reduces the volume of blood being sent to the lungs for oxygenation, ultimately decreasing the oxygenated blood available to be delivered to the rest of the body, including the myocardium.