(MHD) CHF

Question 1

Name the (2) general types of CHF

Answer 1

Forward and Backward Failure

Question 2

Define Forward Failure

Answer 2

The inability of the heart to pump blood forward at a sufficent rate to meet the metabolic demands of the body

Question 3

Define Backward Failure

Answer 3

The ability to pump blood at a sufficent rate only if the cardiac fillling pressures are abnormally high.

Question 4

Name the 3 general groups of disorders that lead to CHF

Answer 4

1. Disorders of Impaired Contractility (ex. MI, dilated cardiomyopathy, etc.)
2. Disorders of Markedly Increased Afterload (ex. severe aortic stenosis, uncontrolled hypertension, etc.)
3. Disorders with Impaired Ventricular Relaxation/Decreased Filling (ex. restrictive cardiomyopathy, constrictive pericarditis, etc.)

Question 5

How can EF be effected in heart failure?

Answer 5

You can have heart failure with reduced ejection fraction (HFrEF) or HF with preserved ejection fraction (HFpEF)

Question 6

HFpEF is associated with what part of the heart contraction cycle?

Answer 6

Heart Failure with Preserved EF is associated with Diastole. It is aka Diastolic Heart Failure. There is decreased compliance so filling is lower, but EF is not changed.

Question 7

HFrEF is associated with what part of the heart contraction cycle?

Answer 7

Heart Failure with Reduced Ejection Fraction is associated with systole. It is aka Systolic Heart Failure.

Question 8

Describe the relationship between design of the RV and its ability to deal with pressure changes.

Answer 8

sThe RV is much more compliant than the LV and as such can tolerate much larger changes in filling without a major change in pressure.

The RV has thin walls and was not designed for large pressure work (due to the much lower pressure in the pulmonary circulation) and as a result is very susceptible to acute changes in pulmonary vascular resistance.

Question 9

The (3) major causes of right-sided heart failure

Answer 9

1. Cardiac causes (primarily LV failure)
2. Pulmonary parenchymal disease (ex. COPD)
3. Pulmonary vascular disease (ex. PE)

Question 10

The (4) Compensatory mechanisms to maintain CO in CHF

Answer 10

1. Frank-Starling Mechanism (length-dependent activation)
2. Autonomic Nervous System (Baroreceptor response)
3. Renal-compensation (RAA)
4. Ventricular Remodeling

Question 11

Where does Post-MI Ventricular remodeling occur?

Answer 11

It can occur in either the infarcted or the noninfarcted regions of the heart

Question 12

What occurs to ventricular shape and size in the long term following acute MI

Answer 12

Hypertrophy/dilation of noninfarcted segments, as they attempt to compensate for the dead areas.

Question 13

Concentric vs Eccentric Hypertrophy

Answer 13

Concentric: there is no overall growth in outward dimensions, but the wall gets thick and lumen gets small.

Eccentric: Overall size and volume of heart grow

Question 14

What ultimately serves as the stimulus for the increased cardiac muscle growth associated with hypertrophy?

Answer 14

Increased wall stress.

Some sort of volume/pressure overload or Post-MI dysfunction causes an increase in systolic or diastolic wall stress, and this utimately leads to hypertrophy.

Question 15

Name (3) major risk factors for the development of Post-MI ventricular remodeling.

Answer 15

1. Increased infarct size
2. Decreased EF
3. An MI which is anterior

Question 16

Relationship between ventricular remodeling and CHF

Answer 16

Remodeling often precedes the development of symptoms of CHF by months/years. If you prevent/ slow remodeling, you can prevent/delay CHF.

Question 17

Name (3) major drug classes which prevent ventricular remodeling

Answer 17

1. ACE Inhibitors
2. Beta Blockers
3. Aldosterone Antagonists