Heart Failure - Auchampach Flashcards Preview

M2 Cardiovascular > Heart Failure - Auchampach > Flashcards

Flashcards in Heart Failure - Auchampach Deck (43):
1

What is heart failure?

Inability of the heart to pump blood equal to the metabolic rate of the body

2

What is the formula for cardiac output?

CO=heart rate*stroke volume

3

What factors influence stroke volume? Do they increase or decrease stroke volume?

Contractility- Increase
Preload-Increase
Afterload-Decrease

4

How is 'preload' measured?

Left Ventricle End Diastolic Volume (or pressure?)

IE: how much blood can be loaded into the left ventricle

5

What is afterload?

Resistance the ventricle overcomes to empty it's contents

IE: the pressure in the aorta

6

What can change contractility?

Availability of intracellular calcium

7

What is compliance?

The change in pressure caused by an increase in volume

8

When does isovolumic contraction occur?
(answer for the left side of the heart)

After the closure of the mitral valve

9

When does isovolumic relaxation occur?
(answer for the left side of the heart)

After the closure of the aortic valve

10

What are three general causes of heart disease?

Impaired Ventricular Contractility
Increased Afterload
Impaired Relaxation/Filling

11

What are two ways to classify heart failure? Which typically combine?

Diastolic dysfunction vs Systolic dysfunction
Reduced Ejection Fraction vs Preserved Ejection Fraction

Diastolic dysfunction usually pairs with preserved EF
Systolic dysfunction usually pairs with reduced EF

12

What are some causes of increased afterload?

Hypertension
Aortic Stenosis

13

What are some causes of impaired contractility?

Coronary Ischemias (transient or infarction)
Overload caused by regurgitations
Cardiomyopathy

14

What are some causes of impaired relaxation/filling?

Left ventricle hypertrophy
Myocardial fibrosis
Pericardial constriction/tamponade

15

What is unique about the right side of the heart? What does this mean in terms of heart failure?

RV has high compliance

Right-sided heart failure typically due to an increase in afterload and is SECONDARY TO LUNG DYSFUNCTION

16

What are some examples of neurohormonal activation in response to decrease cardiac output?

Sympathetic activation
Renin-Angiotensin-Aldosterone activation
Anti-diuretic hormone

17

Why is neurohormonal control not a viable long-term solution to heart failure?

CV system is a closed loop! You can not increase preload without eventually increasing afterload, leading to decrease cardiac output.

18

What are some (very general) causes of heart failure?

Increased metabolic demand
Increased circulating volume
Increased afterload
Decreased contractility
Bradycardia

19

What would increase metabolic demand?

Fever
Infection
Anemia
Hyperthyroidism
Pregnancy

20

How does the heart association classify heart failure?

Class I- no limitation in physical activity
Class II- dyspnea, fatigue with moderate exertion
Class III- dyspnea with minimal exertion
Class IV- dyspnea at rest

21

What is the prognosis of heart disease?

5 year mortality rate is 45-60%

Class II or high is 60% mortality rate

22

What are the 4 goals of treating systolic heart failure?

Fix underlying causes
Manage symptoms
Modulate neurohormonal response
prolong survival

23

What are 5 classes of drugs used to treat heart failure with preserved ejection fraction? Why are these used?

Diuretics
Renin-Angiotensin-Aldosterone Inhibitors
Beta-blockers
Vasodilators
Positive Inotropic agents

Decrease afterload

24

What is an example of a positive inotrope?

Digoxin

25

What are Digoxin's primary effects? Secondary effects?

Primary
-Increases contractility
-Increases Stroke Volume
-Slows Heart Rate

Secondary
-Arterial and Venous Dilation
-Normalized Arterial Baroreceptors

26

What is the mechanism of action for digoxin?

Inhibits the Na/K ATPase

The decreased Na gradient decreases the power for the Ca/Na exchanger, meaning that Ca stays in the cell longer

27

How does digoxin affect heart rate?

Increased activity of the vagal nerve leading to reduced firing at the SA node and decreased conduction at the AV node.

28

What is seen on an ECG of a patient taking Digoxin?

Increased PR interval

29

What are some negative effects of Digoxin?

-Affects all electrical systems (GI, visual, neuro, muscular)
-Increased toxicity with hypokalemia
-Multiple drug interactions

30

When is Digoxin used?

-Heart failure patients with LV systolic dysfunction AND atrial fibrillation
-Heart failure patients who have sinus rhythm despite maximal doses of other therapies

31

How does Milrinone work?

Phosphodiesterase Inhibitor

Positive inotrope that also produces vasodilation

32

How do dobutamine and dopamine work?

Dobutamine
-Beta1 receptor agonist, positive inotrope

Dopamine
-Simpathomimetic, positive inotrope

33

Why are diuretics used to treat heart failure?

-reduced preload
-reduced heart size
-reduced edema

34

What are three classes of diuretics? What is the main drug associated with each class?

-Loop diuretics (furosemide)
-Thiazide diuretics (chlorothiazide)
-K sparing diuretics (amiloride, triamterene)

35

What is the main side effect of diuretic therapy? What can be done to prevent it?

hypokalemia

prescribe K-sparing diuretics

36

What does angiotensin do? What does aldosterone do?

Angiotensin causes aldosterone secretion; aldosterone causes water and sodium retention

37

What are common ace inhibitors? Why are they prescribed for heart failure?

captopril, lisinopril, enalapril

Decrease afterload and preload
Increase survival rate

38

What are some potential side effects of ACE inhibitors?

Dry cough
Decreased renal function
hyperkalemia when used with aldosterone antagonists

39

What is an alternative for patients who can not tolerate ACE inhibitors?

Angiotensin Receptor blockers

40

What do aldosterone antagonists do? What are some examples?

Block aldosterone to reduce edema, decrease fibrosis

Spironolactone, eplerenone

41

What do beta-adrenergic receptors antagonists do?

Decrease BP, arrythmias
Increase ventricular function
Decrease mortality rate

42

What is important about dosing for beta-adrenergic receptor antagonists?

They can initially worsen cardiac function, so dose must start low and then increase.

43

What is Neprolysin?

peptidase that degrades vasoactive peptides