Question 1

Nitroglycerin is a mainstay for treatment of angina pectoris because:&#10;A) Redistributes intracardiac blood flow to the subendocardium&#10;B) It causes venodilation, reducing venous return to the heart&#10;C) Causes an increase in LV end-diastolic pressure&#10;D) Decreases afterload through precapillary vasodilation&#10;E) A, B, and D

Accepted Answer

NTG dilates both arterial and venous circulations, reducing preload and afterload and thereby reducing cardiac oxygen consumption.

Question 2

Clinical problems with vasodilators include&#10;A) Renin release&#10;B) A phenomenon where blood flow is shunted from ischemic tissues to healthier tissues&#10;C) Activation of the sympathetic nervous system&#10;D) B and C&#10;E) All of the above

Accepted Answer

Administration of vasodilators initiates an increase in sympathetic tone, increasing heart rate and contractility; it also increases renin-angiotensin system activity. Tissues that are already ischemic have a developed vasodilation pattern, so vasodilation within healthy tissues will tend to "steal" perfusion from those tissues that need it most.

Question 3

Phosphodiesterase type 5 inhibitors&#10;A) Are primarily used in congestive heart failure&#10;B) Cause increased levels of cGMP in certain tissues, which leads to increased NO concentrations and vasodilation&#10;C) A and B&#10;D) Are vasodilators used in the treatment of hypertension&#10;E) A, B, and D

Accepted Answer

PDE5 is primarily found in the corpus cavernosum of the male as well as the retina. Inhibition of this enzyme leads to increased NO and cGMP, leading to smooth muscle relaxation and filling of the blood vessels.

Deck 24: Vasodilators and Nitric Oxide Synthase