Heart Failure (General)

Question 1

What is Heart Failure

Answer 1

Cardiac Output is not enough to meet metabolic demands of body

Progressive Syndrome

Question 2

Causes of Heart Failure

Answer 2

Decreased Contractility:
- Diseases of Myocardium
- Cardiotoxic Drugs
- Pressure Overload
- Volume Overload

Restriction in Ventricular Filling:
- Diastolic Dysfunction
–> Ventricle Stiffness

Question 3

Compensatory Mechanism during Heart Failure and their effect

Answer 3

When cardiac function significantly decreases compensatory mechanisms are triggered to maintain adequate CO
–> These mechanism make situation worse instead of better (Counter Regulatory)

Question 4

Heart Failure
(Counter Regulatory Mechanisms)

Answer 4

Kidney interprets reduced prefusion as ineffective blood volume
- Kidney thinks body is bleeding
–> Stimulate Na+ and H2O retention (RAS)

Vasoconstriction
- Redistribute blood flow from non-essential organs to coronary and cerebral circulations

Ventricular Hypertrophy
- Remodeling of Heart and Hypertrophy

Question 5

What are the two types of RAS Inhibitors

Answer 5

ACE Inhibitors
Angiotensin Receptor Blockers (ARBs)

Question 6

RAS Inhibitors Mechanism of Action

Answer 6

Blocks formation of Ang II
- Inhibits release of aldosterone
- Reduced vascular resistance and afterload
- Improve tissue perfusion
- Reduces Na+ reabsorption

Question 7

Beta-Adrenoceptor Antagonist Mechanism of Action

Answer 7

Reduces heart rate and blood pressure
- Prolongs Diastolic Filling
- Reduces Detrimental remodeling of heart
- Inhibits Renin

Question 8

Beta-Adrenoceptor Antagonist Dosage

Answer 8

Normal Dose Beta-Adrenoceptor Antagonists reduce CO
- Need to be started at low doses and slowly increased

Question 9

Aldosterone Receptor Antagonists Mechanism of Action

Answer 9

Competitive Antagonists of Aldosterone Receptor in Kidney
- Inhibits expression of transporters (Changes nuclear receptor’s gene expression)

Overall Effect: Inhibits Na+ reabsorption and Water Retention

Question 9

What kind of Receptor are Aldosterone Receptors

Answer 9

Mineral Corticoid Receptor (Class 1 Nuclear)

Question 10

Furosemide Mechanism of Action

Answer 10

Inhibits Na+/K+/2Cl- transporters in loop of Henle
- Potent Diuretic, more water eliminated
–> Decrease Na+ Reabsorption
–> Decrease Water Reabsorption
–> Decrease Blood Volume

Question 11

Digoxin
- When to use?

Answer 11

Used in heart failure patients with:
- Chronic atrial fibrillation
- Remain symptomatic after ACEI and Diuretic treatments

Question 12

Digoxin
- What class?

Answer 12

Cardiac Glycoside with Positive Inotropic Effect
- Changes the force of contraction of the heart

Question 13

Digoxin
- Mechanism of Action

Answer 13

Inhibits Na+/K+ ATPase pump
- Increases Contraction Force
- Slows Heart Beat
- Increases Ventricular Filling

Less Na+ Influx and Less transport of Ca2+
- More Ca2+ in Cardiac Myocyte
–> Stronger Contractions
–> Slower Heartbeat
–> Increased Ventricular Filling

Question 14

Isosorbide Mononitrate
- Mechanism of Action

Answer 14

Metabolized with release of NO
- Relax veins and Reduces central Venous Pressure
–> Reduces Preload

Question 15

NO Mechanism

Answer 15

Nitric Oxide diffuses into smooth muscle
- Activates GC –> Converts GTP into cGMP
–> Causes Relaxation

Question 16

Hydralazine
- Mechanism of Action

Answer 16

Causes a fall in BP (Reduces Afterload)
- Inhibits IP-mediated intracellular Ca2+ release in SMC of arteries and arterioles
–> Imhibits Calcium release