Clinical CHF

Question 1

What 2 formulas must we absolutely know?

Answer 1

1. BP= CO x TPR

2. CO= HR x SV

Question 2

What dictates the CO?

Answer 2

the filling time (preload), afterload, and inotropism (contractility).

Question 3

Is the systemic vascular resistance high or low when the CO is low?

Answer 3

the systemic vascular resistance is high

Question 4

What are the 2 neurohumoral responses that control systemic vascular resistance?

Answer 4

1. sympathetic nervous system

2. renin-angiotensin aldosterone system (RAAS)

Question 5

What happens to pressure if you increase volume?

Answer 5

you increase pressure also because they are in a direct linear relationship.

Question 6

What happens if you have too little volume?

Answer 6

you stimulate the RAAS system to retain salt and increase volume and thus pressure.
* The body can overshoot though when it does this.

Question 7

**What are the 2 types of heart failure?

Answer 7

1. reduced= systolic dysfunction; EF

2. diastolic dysfunction

Question 8

How do you treat CHF?

Answer 8

find the underlying etiology

Question 9

What are the etiologies of CHF?

Answer 9

The loss of a critical quantity of functioning myocardial cells after injury to the heart due to:

1. IHD
2. hypertension
3. Idiopathic cardiomyopathy
4. Infections (viral myocarditis, Chagas’ disease)
5. Toxins (alcohol or cytotoxic drugs)
6. valvular disease
7. prolonged arrhythmias

Question 10

Where do you begin when a patient comes in?

Answer 10

with the history!

Question 11

**What are the 4 controlling mechanisms of systolic dysfunction or reduced LV function?

Answer 11

1. preload
2. afterload
3. inotropism (contractility)
4. HR

Question 12

What is the initial treatment for CHF?

Answer 12

to relieve the symptoms

Question 13

**What is heart failure?

Answer 13

a complex clinical syndrome in which the heart is incapable of maintaining a CO adequate to accommodate metabolic requirements and the venous return.

Question 14

What is the New York Heart Association (NYHA) classification system for heart failure?

Answer 14

1. SOB with severe exertion
2. SOB with moderate exertion
3. SOB with mild exertion
4. SOB with rest
   * you can go from 1 to 2, 2 to 4, 4 to 1…

Question 15

How does the American College of Cardiology rate heart failure?

Answer 15

A. Have the possibility of developing heart failure because you have risk factors.
B. You’re in heart failure and you don’t know it (due to compensatory mechanisms: RAAS and sympathetic NS).
C. You’re in active heart failure.
D. You have a cardiomyopathy and you will die.

Question 16

What is the incidence (new cases each year) of heart failure?

Answer 16

a million

Question 17

What should you think when end systolic or diastolic volume increases?

Answer 17

• neck vein distention
• hepatojugular reflux
• sacral or lower extremity edema

Question 18

What should you think with pulmonary congestion?

Answer 18

• SOB
• CO is low
• systemic vascular resistance is up
• hypoperfusion
• cool to the touch distally

Question 19

What are the symptoms of left ventricular dysfunction?

Answer 19

• dyspnea
• tachycardia
• cough
• hemoptysis

Question 20

What are the physical signs of left ventricular dysfunction?

Answer 20

• basilar rales
• pulmonary edema
• S3 gallop
• pleural effusion
  Cheyne-Stokes respiration

Question 21

What are the 3 compensatory mechanisms of heart failure?

Answer 21

1. Frank-Starling mechanism= increase volume, increase contractility.
2. Neurohormonal Activation= SNS, RAAS, ADH
3. Ventricular remodeling

Question 22

So what does the body do when we have a decreased MAP?

Answer 22

it will compensate via the sympathetic nervous system (SNS) to increase this by increasing SV, HR, and TPR:
MAP= (HR x SV) x TPR

Question 23

What are ACE inhibitors and ARBs?

Answer 23

afterload reducers. They inhibit the vasoconstriction and sodium retention that occurs in the kidney during sympathetic stimulation.
*Note: ARBs are NOT inferior to ACE inhibitors

Question 24

Why do beta blockers PROLONG LIFE?

Answer 24

because they block the sympathetic stimulation on the heart that occurs during heart failure and would lead to myocardial toxicity, increased arrhythmias, and disease progression without them!

Question 25

What does Vasopressin (ADH) do?

Answer 25

when BP is low, baroreceptors stimulate the hypothalamus to cause the anterior pituitary to release ADH, which travels in the blood to the kidney to cause water retention and vasoconstriction, thus increasing BP.

Question 26

What are the 3 natriuretic peptides (other neurohormones)?

Answer 26

1. atrial natriuretic peptide (ANP)= on the wall of the atrium and is secreted due to overstretch causing diuretic and vasodilatory properties. 2. brain natriuretic peptide (hBNP)= found in the ventricles and has diuretic and vasodilatory properties. * Used mostly to gauge progression after a few days. Because this is a marker for heart failure, if it drops, we know we are on the right path. 3. C-type natriuretic peptide (CNP)= predominantly found in the CNS

Question 27

What are the important endothelium derived relaxing factors (vasodilators)?

Answer 27

- NO - Bradykinin - Prostaglandins

Question 28

What is the endothelium-derived constricting factor?

Answer 28

endothelin 1

Question 29

**How should you approach a class 2 or 3 heart failure patient?

Answer 29

start them on an ACE or ARB and see where they go from there. If their potassium and kidney function are good, but they are still in heart failure, then you can add spirinolactone. If you use beta blockers, the goal is to get to the highest dose recommended (doesn't always work because the pts BP won't tolerate it). If you can't get to the max dose, you shoot for a goal HR of 60-70.

Question 30

**Do diuretics prolong life?

Answer 30

NO! They are just used to relieve symptoms. So you use as little of these as possible, and as much of the ACEs, ARBs and beta blockers that you can!

Question 31

When can you use digoxin?

Answer 31

If you've maxed out on beta blockade and ACEs or ARBs, then if you're still in stage 3 or 4 heart failure, you can add digoxin in SMALL doses.

Question 32

What can cause digoxin toxicity?

Answer 32

hypovolemia (due to drug level going up as volume goes down), or drugs that compete on the myocardial binding sites with digoxin that put it into the serum.

Question 33

What is the half-life of digoxin?

Answer 33

36 hours!

Question 34

Why must we be SOOO careful with digoxin?

Answer 34

because it has a narrow therapeutic index, can cause heart block, or arrhythmias. You will also get yellow vision!

Question 35

If the pts kidney function is impaired, can you use ACE inhibitor or ARBs?

Answer 35

NO! Instead use long acting nitroglycerin (venodilator) and hydralazine (arterial dilator).

Question 36

How do you diagnostically evaluate new onset heart failure?

Answer 36

1. determine the type of cardiac dysfunction (systolic vs. diastolic) 2. determine etiology 3. define prognosis 4. guide therapy

Question 37

What do we do if we've tried all anti-arrhythmic drugs in pts who have reduced LV function (

Answer 37

use a pacemaker= reads and memorizes every beat of your heart! It recognizes the difference between normal beats and ventricular tachycardia. It is programmed at a higher rate than your v-tach, so it will go faster than the v-tach to make the myocardium refractory, preventing the depolarization from going through! If your heart doesn't beat in over 8 seconds, it will defibrillate you, and it feels like you were kicked in the chest by a horse!

Question 38

**How do you treat preserved heart failure (diastolic dysfunction)?

Answer 38

by controlling blood pressure. Use whatever you want, beta blockers, diuretics, ACE inhibitors...