Congestive Heart Failure

Question 1

What is heart failure?

Answer 1

Heart fails to meet the metabolic demands of tissues

Question 2

What is Congestive Heart Failure?

Answer 2

-Increased LV pressure at end diastole

-Increased pulmonary pressure and results in pulmonary edema

Question 3

What is the most common cause for CHF?

Answer 3

CAD - Coronary artery disease

Question 4

What are the 2 types of CHF?

Answer 4

Systolic - ejection problem
Diastolic - filling problem

Question 5

What type of medication do you give for systolic HF?

Answer 5

Diuretics
positive iontropes

Question 6

What type of medication do you give for diastolic HF?

Answer 6

CCB

not positive iontrops

Question 7

What are the 4 factors of cardiac performance? How are these altered in HF?

Answer 7

1. Preload
2. Afterload
3. Contractility
4. HR

Question 8

Define the Starling law

Answer 8

Strength of contraction increases when stretched

The more blood is in the heart because it is congested… the harder its gonna have to pump

Question 9

Describe the strategies and list the major drug groups used in the treatment of acute heart failure and chronic failure.

Answer 9

• Calcium (Ca-Cl; Ca-gluconate)
• Diuretics
• Cardiac glycosides (digoxin)
• Positive inotropes
• PDE3 Inhibitors (milrinone) — >Prevents breakdown of cAMP = More cAMP = more forceful contraction

Question 10

Draw the molecular mechanisms controlling normal cardiac contractility.

Answer 10

a. Voltage-gated calcium channels open
b. calcium enters cell
c. Ca binds to channel in SR,
d. Ryanodine receptors open causing release of stored calcium
e. Bathes troponin-tropomyosin complex in Ca
i. Dissociates from actin
f. Frees actin to interact with myosin
i. ATP; cross-bridge cycling
ii. Contraction
g. SERCA pumps Ca back into SR
h. Na/Ca exchanger on cell membrane
i. 3 Na in for 1 Ca out
ii. Restores Ca balance to normal to pepare for next AP
i. Na/K/ATPase
i. Restores Na balance

Question 11

Drugs: Digoxin

Answer 11

Cardiac glycoside
Positive inotrope

PROTOTYPE

Digitalis family - foxglove plant

Narrow therapeutic index
Inhibits Na+/K+ ATPase pump
Reverses Na/Ca exchange pump

65-80 PO bioavailability

Decreases QT

Tx: Heart failure , Afib

Question 12

What plant is digoxin from?

Answer 12

Foxglove plant

Question 13

What drug inhibits Na/K ATPase pump?

Answer 13

Digoxin

Question 14

How does Digoxin affect ions?

Answer 14

Hyperkalemia
Hypercalcemia
Hypomagnesia

Question 15

Drugs: Milrinone

Answer 15

Phosphodiesterase Inhibitors
PDE3: enzyme that inactivates cAMP and cGMP

Positive inotropic without inhibiting Na/K/ATPase

Increases/prolongs Ca
Main action from vasodilation

Question 16

Explain the beneficial effects of diuretics, vasodilators, ACE inhibitors, and other drugs that lack positive inotropic effects in heart failure

Answer 16

• ACE inhibitors (-pril): Reduce compensatory responses to failure; Reduce afterload
• ARBs (-sartan): Reduce afterload
• Vasodilators: Reduction in preload & afterload

Question 17

Discuss the reasoning behind giving beta-blockers for heart failure.

Answer 17

Beneficial for patients with diastolic failure. diastolic HF is a filling problem. Decreasing heart rate allows more time for filling the ventricles.

Question 18

What do diuretics do?

Answer 18

Reduce salt and water retention –>
- reduces preload
- edema
- cardiac size

improves overall heart efficiency

Question 19

-pril

Answer 19

ACE inhibitor

Question 20

-sartan

Answer 20

ARBs

Question 21

What does a vasodilator do in heart failure?

Answer 21

reduce preload/afterload

Question 22

What medications do you want to avoid in HF?

Answer 22

NSAIDs
Thiazolidinediones
Metformin

Question 23

Why cant you take metformin when you have HF?

Answer 23

Lethal lactic acidosis

Question 24

Tx for acute HF include IV:

Answer 24

Diuretics
Dobutamine
Vasodilators