II - Cardiovascular

Question 1

Inotropy

Answer 1

Intrinsic property of the sarcomere to shorten (actin-myosin interaction) or contract

Question 2

Chronotropy

Answer 2

Affecting the heart rate
Constant flux between sympathetic and parasympathetic tone
Congestive heart failure increases sympathetic tone

Question 3

Preload

Answer 3

The pressure that stretches the right or left ventricles prior to contraction (systole).

Both pressure and volume dependent.

Increased preload elicits the Frank-Starling mechanism (increases the force of contraction).

Question 4

Afterload

Answer 4

Force that opposes ventricular ejection.

Afterload is not the same as blood pressure, but we often use as a clinical surrogate.

Afterload can also be “fixed” as in an obstruction like pulmonic stenosis.

Question 5

Systolic function

Answer 5

Collective contribution of all cardiac cells; the function of the chamber as a whole to squeeze

Question 6

Diastolic function

Answer 6

The ability of the chambers to relax after contraction and to fill with blood (active and passive components of relaxation).

Relaxation is also referred to as lusitropy.

Question 7

Congestive heart failure

Answer 7

Fluid accumulation in tissues (lungs or cavities) as decompensation from the blood volume augmenting effects of the RAAS system trying to maintain cardiac output.

Often referred to as backward failure.

Question 8

Forward failure signs are related to poor cardiac output: _________________, ______________, _______________.

Answer 8

Hypotension
Hypothermia
Pallor/poor perfusion

Question 9

List five categories of cardiovascular drugs.

Answer 9

Positive inotropes
Preload reducers
Afterload reducers
Antiarrhythmics and heart rate modification (chronotropy)
Anti-hemostatic drugs

Question 10

What can we do to help the heart?

Answer 10

Change contractile properties
Change loading (volume or resistance in the system)
Change heart rate responses
Suppress abnormal rhythms

Question 11

Positive inotropy mechanisms of action

Answer 11

Increasing the quantity of intracellular calcium
Increasing the sensitivity of contractile proteins to calcium
Combination of both

Question 12

List the two major drugs used in general practice for heart disease and heart failure.

List 2-3 additional drugs.

Answer 12

Pimobendan
Digoxin

Dobutamine, Dopamine, Milrinone (same class as Pimobendan)