Cardiovascular Physiology and Pharmacology Flashcards

In a patient with aortic stenosis, which hemodynamic pattern is expected?

Answer: High transaortic gradient, concentric LV hypertrophy

Severe aortic stenosis creates a high pressure gradient across the valve and leads to concentric left ventricular hypertrophy from chronic pressure overload.

The coronary perfusion pressure is defined as:

Answer: Aortic diastolic pressure minus LVEDP

Coronary perfusion pressure = aortic diastolic pressure minus left ventricular end-diastolic pressure, as most LV coronary flow occurs during diastole.

Which receptor subtype mediates vasodilation when activated by dopamine at low doses (1-3 mcg/kg/min)?

Answer: DA1 dopaminergic receptors

At low doses, dopamine activates DA1 receptors in renal and splanchnic vasculature, causing vasodilation and increased renal blood flow.

What is the primary mechanism by which volatile anesthetics cause myocardial depression?

Answer: Reducing intracellular calcium availability and sensitization

Volatile anesthetics impair calcium release from the sarcoplasmic reticulum and reduce myofilament calcium sensitivity, depressing myocardial contractility.

In the pressure-volume loop of the left ventricle, the width of the loop represents:

Answer: Stroke volume

The horizontal width of the LV pressure-volume loop represents stroke volume (the difference between end-diastolic and end-systolic volumes).

Which of the following best describes the effect of milrinone on cardiac physiology?

Answer: Positive inotropy and vasodilation via PDE3 inhibition

Milrinone inhibits phosphodiesterase III, increasing cAMP, causing positive inotropy in the heart and vasodilation in peripheral vessels (inodilator).

Vasopressin (ADH) causes vasoconstriction primarily through which receptor?

Answer: V1 receptors on vascular smooth muscle

V1 receptors on vascular smooth muscle mediate vasopressin-induced vasoconstriction via the phospholipase C/IP3 pathway and intracellular calcium release.