12/9/2014 Medical Physiology CC: Heart Failure Harold Smulyan

Question 1

What is the definition of heart failure?

Answer 1

Inability of the heart to meet the metabolic needs of the body at normal filling pressures

Question 2

What is important to distinguish HF from?

Answer 2

Cardiac dysfunction with successful adaptation

Question 3

HF happens when…

Answer 3

…adaptation fails and becomes part of the problem

Question 4

What is the clinical diagnosis of HF?

Answer 4

• no single finding

* a complex of findings

Question 5

What are the 2 different diagnosis of which HF becomes the final common pathway?

Answer 5

1. Decreased circulatory supply to the body

2. Increased circulatory demand from the body

Question 6

What are some of the conditions that can decrease circulatory supply to the body?

Answer 6

• coronary heart disease
  
  • MI
  • ischemic cardiomyopathy
• valvular heart disease
• cardiomyopathy

Question 7

What are some of the conditions that can increase circulatory demand from the body?

Answer 7

• hypertension
• thyrotoxicosis
• anemia
• A-V fistula

Question 8

Adaptive mechanisms

Answer 8

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

Question 9

What are the 3 main adaptive mechanisms of HF?

Answer 9

1. Frank – Starling
   (short term)
2. Neuro-hormonal (intermediate)
   a. Renal
3. Hypertrophy
   (long term)

Question 10

In a ventricular EDV vs. ventricular performance diagram (F-S mechanism):

Answer 10

1. Normal curve shows improved ventricular performance when the end-diastolic volume is increased (increased pre-load or venous return)
2. Normal curve moves upward and to the left with exercise or increased sympathetic stimulation.
3. Abnormal curve (in green) moves down and to the right with impaired ventricular performance.

Question 11

In a LV filling pressure (left atrial pressure in diastole) vs. LV stroke work diagram:

Answer 11

1. groups above and to the left of normal show the effects of exercise and/or sympathetic stimulation
2. groups down and to the right of normal show progressive reduction of the change in stroke work with increasing LV filling pressure
3. with increasingly severe LV dysfunction the LV filling pressure reaches 25mmHg, where the oncotic pressure of the plasma is exceeded and fluid crosses the alveolar membrane and enters the pulmonary alveoli

Question 12

The neurohumoral adaptive mechanism of HF is related to:

Answer 12

Sympathetic stimulation -increased plasma NE

• redistribution of CO
• maintains flow to the brain and heart at expense of skin, skeletal muscle, gut and kidneys

Question 13

What are the adaptive mechanisms of HF in the renal system?

Answer 13

Stimuli:

• decrease GFR
• decrease RBF
• increase aldosterone

Response:

• increase sodium and water retention
• increase plasma volume
• increase venous return
• increase venous pressure

Question 14

Beta 1 receptor density is ___ and Beta 2 receptor density is ___ by HF

Answer 14

reduced; not reduced

Question 15

LV contractility (dp/dt) ___ with addition of intracoronary dobutamine in patients with HF

Answer 15

decreases

Question 16

What is the common theme between the stuff listed below and HF?

PNE = Plasma norepinephrine 
PRA = Plasma renin activity 
AVP = Arginine vasopressin 
ANP = Atrial natriuretic peptide 
ENDO = Endothelin

Answer 16

They are all increased with HF

Question 17

1. If abnormality can be corrected, hypertrophy will ___

2. If abnormality is not corrected, myocardial dysfunction will ___

Answer 17

1. regress

2. worsen and become permanent

Question 18

Ejection Fraction equals

Answer 18

(EDV-ESV)/EDVx100

Question 19

What are two responses to hemodynamic overload?

Answer 19

Pressure overload

Volume overload

Question 20

How does hypertrophy maintain pump function (CO)?

Answer 20

By keeping wall stress near normal

Question 21

Pressure overload ___ systolic wall stress

Answer 21

increases

Question 22

Volume overload ___ diastolic wall stress

Answer 22

increases

Question 23

Both pressure and volume overloads lead to ___

Answer 23

ventricular remodeling

Question 24

In pressure overload, sarcomeres arranged in ___

Answer 24

parallel

Question 25

In volume overload, sarcomeres arrange in ___

Answer 25

series

Question 26

Pressure overload leads to ___

Answer 26

concentric hypertrophy

thicker LV

Question 27

Volume overload leads to ___

Answer 27

eccentric hypertrophy

greater LV volume

Question 28

h/R: ratio of wall thickness to chamber radius –> ___ in pressure
overload

Answer 28

greater

Question 29

Adaptation disadvantage of F-S response

Answer 29

High LVEDP -pulmonary edema

Question 30

Adaptation disadvantages of neuro-humoral response

Answer 30

1. increased myocardial O2 consumption
2. arrhythmias
3. diminished response to sympathetic stimulation
4. blunted baroreceptor function
5. increased systemic vascular resistance

Question 31

Adaptation disadvantages of renal response

Answer 31

1. peripheral/organ edema

2. decreased renal function

Question 32

Adaptation disadvantages of myocardial hypertrophy response

Answer 32

1. decreased contractility
2. necrosis and apoptosis
3. decreased coronary reserve
4. changes in matrix (diastole)

Question 33

What are some of the main failure maladaptations?

Answer 33

• worsening LV function
• fluid retention (pulmonary edema)
• excessive increase in vascular resistance
• renal failure

Question 34

Therapies range:

Answer 34

• addressing underlying cause
• medications such as diuretics, vasodilators and beta blockers
• LVAD
• transplantation