Heart Failure

Question 1

“definition” of heart failure

Answer 1

inability of the heart to meet the metabolic needs of the body

• to be distinguished from cardiac dysfunction with successful adaptation
• when adaptation fails and becomes part of the problem
• clinical diagnosis w/ no one single finding, but a complex of findings

Question 2

what are 2 causes of heart failure and examples?

Answer 2

1. decreased circulatory supply to the body
   - coronary heart disease (myocardial infarction, ischemic cardiomyopathy)
   - valvular heart disease (aortic stenosis, mitral regurgitation)
   - cardiomyopathy
2. increased circulatory demand from the body
   - HTN (increased resistance)
   - thyrotoxicosis (overactive thyroid)
   - anemia (decreased O2 carrying capacity)
   - AV fistula (manmade or on dialysis)

Question 3

what are 3 adaptive mechanisms for heart failure?

Answer 3

compensations that maintain pump function in presence of heart disease or increased demand

1. Frank-Starling (short term)
2. Neuro-hormonal (intermediate; renal)
3. Hypertrpohy (long term)

Question 4

how does Frank-Starling help heart failure?

Answer 4

if one exercises or increases sympathetic stimulation with heart failure, the decreased contractile state of the myocardium can increase ventricular performance, not as good as normal non-exercising, but much better than plain heart failure

Question 5

what happens to B1 receptors in sympathetic stimulation in heart failure?

Answer 5

B1 receptors are exhausted due to chronic stimulation

-receptor synthesis decreases

Question 6

plasma NE levels and heart failure survival

Answer 6

increasing levels of PNE are associated with decreasing length of survival in heart failure
-since PNE is a rough estimate of the sympathetic stimulation, increasing sympathetic stimulation can still be bad

Question 7

how does blood flow to muscles compare in heart failure?

Answer 7

less CO to muscle if CHF
-less CO in general, but from what is left, maintain flow to the heart and brain at expense of skin, skeletal muscle, gut, and kidneys

Question 8

what are the renal adaptations to heart failure?

Answer 8

stimuli: less GFR and renal blood flow, more aldosterone (there is also more AII)
response: increased Na and H2O retention, plasma volume, venous return, and venous pressure

Question 9

how do beta1 and beta2 receptor density differ in heart failure?

Answer 9

B1 receptor density is reduced by heart failure, but not B2 receptor densities

Question 10

atrial and brain natriuretic factors in heart failure

Answer 10

both are counter-regulatory (BNF is actually from ventricles)
-both promote vasodilation, natriuresis, and suppress RAS

Question 11

what are 5 hormones that are higher in heart failure than normal?

Answer 11

plasma NE
plasma renin-angiotensin
vasopressin
atrial natriuretic factor
endothelin

Question 12

hypertrophy and heart failure

Answer 12

increase in myocardial mass - remodeling

• if abnormality can be corrected, hypertrophy will regress
• if not corrected, myocardial dysfunction will worsen and become permanent
• poorer contractile function

Question 13

2 causes of hypertrophy

Answer 13

pressure overload (stenosis w/ increased systolic wall stress) and volume overload (regurgitation with increased diastolic wall stress)

• effort to return wall stress toward normal
• though individual muscles show reduced contractility, maintained pump function (CO) by keeping wall stress near normal

Question 14

types of ventricular remodeling (3 kinds and what they’re caused by)

Answer 14

parallel sarcomeres - concentric hypertrophy (shorter and fatter, with smaller lumen; from pressure overload)
series sarcomeres - eccentric hypertrophy (longer and skinnier, with thinner walls; from volume overload)
physiologic hypertrophy (longer; from volume overload)
CH and EH cause increased expression of embryonic genes

Question 15

what are heart failure adaptation disadvantages for:

1. Frank-Starling
2. Neurohumoral
3. Renal
4. Myocardial hypertrophy remodeling

Answer 15

1. high left ventricle end diastolic pressure causes pulmonary edema
2. increased myocardial O2 consumption, arrythmias, diminished response to sympathetic stimulation, blunted baroreceptor function, increased systemic vascular resistance
3. peripheral/organ edema, decreased renal function
4. decreased contractility, necrosis/apoptosis, decreased coronary reserve, changes in diastole (matrix)

Question 16

right VS left ventricle heart failure diseases

Answer 16

RV: pulmonary embolism, cor pulmonale, mitral stenosis
LV: mitral insufficiency, aortic stenosis/insufficiency, HTN, cardiomyopathy

Question 17

acute VS chronic CHF in heart failure diseases

Answer 17

acute: myocardial infarction, endocarditis
chronic: cardiomyopathy, HTN

Question 18

low VS high cardiac output in heart failure diseases

Answer 18

low: cardiomyopathy, coronary heart disease
high: thyrotoxicosis, anemia, and AV fistula

Question 19

forward VS backward flow in heart failure diseaes

Answer 19

forward: due to low CO
backward: due to high venous pressure

Question 20

systolic VS diastolic in heart failure diseases

Answer 20

S: myocardial infarction
D: preserved EF of 40-5-% in patients
-delayed relaxxation (elterly, HTN), early ischemia
-increased stiffness (rare), infiltrative disease, amyloidosis

Question 21

therapy choices for heart failure

Answer 21

1. treat underlying cause (surgery/transplantation)
2. inotropic agents
3. diuretics
4. venodilator (reduce pre-load)
5. atrial vasodilation (reduce afterload)
6. beta-blockers (blunt sympathetic stimulation)
7. aldosterone antagonists
8. resynchronization (bi or uni-ventricular pacing)
9. internal cardiac defibrillator
10. LV assist device (LVAD)

Question 22

examples of inotropic agents

Answer 22

used to treat heart failure

-digitalis, dobutamine

Question 23

examples of diuretics

Answer 23

used to treat heart failure

• loop
• distal tubule
• furosemide
• thiazide

Question 24

examples of venodilators and arterial vasodilators

Answer 24

used to treat heart failure

• venodilators: nitrates, brain natrial peptide
• vasodilators: ACE inhibitors, angiotensin receptor blockers