Heart Failure

Question 1

What does the term heart failure refer to?

Answer 1

The inability of the CO to keep pace with the body’s demands for supply of nutrients and removal of wastes

Question 2

What does most causes of heart failure result from?

Answer 2

Dysfunction of the left ventricle (systolic and diastolic heart failure)

Question 3

When might the right ventricle be dysfunctional?

Answer 3

In right ventricular failure - pulmonary disease dysfunction

Question 4

What are the 2 most common reasons for heart failure?

Answer 4

Damage to the heart muscle

Prolonged pumping against a chronically increased afterload

Question 5

What are the two major compensatory mechanisms to help restore SV to normal in the early stages of heart failure?

Answer 5

1. Sympathetic activity to the heart is reflexively increased
2. When CO is reduced, the kidneys try to compensate to improve their blood flow by retaining extra salt and water in the body during urine formation to increase blood volume

Question 6

How is heart failure normally functionally classified?

Answer 6

Class I - no limitations; no symptoms from ordinary activities
Class II - slight, mild limitation of activity; pt. comfortable at rest or with mild exertion
Class III - marked limitation of any activity; pt. only comfortable at rest
Class IV - any physical activity brings on discomfort and symptoms occur at rest

Question 7

What are the FOUR stages of heart failure?

Answer 7

Stage A - a high risk HF in the future but NO structural disorder
Stage B - a structural heart disorder but no symptoms at any stage
Stage C - previous or current symptoms of heart failure in the context of an underlying structural heart problem; managed with treatment
Stage D - advanced disease requiring hospital-based support, a heart transport or palliative care

Question 8

What is decompensated heart failure?

Answer 8

As disease progresses and contractility of the heart declines further, the heart reaches a point at which it can no longer pump out a normal SV despite the compensatory measures

Question 9

What does left sided heart failure commonly lead to?

Answer 9

Leads to pulmonary edema because blood dams up in the lungs - Left side > right side heart failure

Question 10

What is systolic heart failure?

Answer 10

This is defined as an inability of the heart to generate an adequate CO to perfuse vital tissues

Question 11

What is the most common cause of decreased contractility and what is disrupted leading to the decrease?

Answer 11

MI is the most common cause of the decreased contractility and this disrupts (or results from the disruption of) myocyte activity

Question 12

What does preload increase with?

Answer 12

Preload, or LVEDV, increases with decreased contractility or when there is an excess of plasma volume (IV administration, renal failure, mitral valvular disease)

Question 13

What is the most common cause of increased afterload?

Answer 13

Increased afterload is most commonly a result of increased peripheral vascular resistance (PVR) such that as seen with hypertension

Question 14

What do catecholamines do in heart failure?

Answer 14

SNS activation initially compensates for a decrease in CO by increasing HR and PVR

Question 15

What does angiotensin II do in heart failure?

Answer 15

Activation of the RAA system not only causes increases in preload and afterload but also causes direct toxicity to the myocardium

Question 16

What does aldosteron do in heart failure?

Answer 16

Aldosterone not only causes salt and water retention by the kidney but also contributes to myocardial fibrosis, autonomic dysfunction, and dysrhyhtmias

Question 17

What does arginine vasopressin (ADH) do in HF?

Answer 17

ADH causes both peripheral vasoconstriction and renal fluid retention which exacerbate hyponatremia and edema in CHF

Question 18

What effects may atrial and brain natriuretic peptides have in CHF?

Answer 18

They are increased in CHF and may have some proactive effect by decreasing preload

Question 19

What is endothlin and what is it associated with in regards to CHF?

Answer 19

Endothelin is a potent vasoconstrictor and it is associated with a poor prognosis in individuals with CHF

Question 20

What does endotoxin to in CHF?

Answer 20

Increased serum levels of endotoxin have been found in many individuals with CHF, especially those with significant peripheral edema, and has been linked to myocoyte apoptosis and release of TNF and interleukins

Question 21

What does TNF do in CHF? What is it?

Answer 21

TNF is a cytokine and is elevated in CHF and contributes to myocardial remodeling, downregulates the synthesis of vasodilator NO, induces myocoyte apoptosis, and may contribute to weight loss and weakness in individuals with CHF - cardiac cachexia

Question 22

What is cardiac cachexia?

Answer 22

Sudden and severe weight loss in individuals with heart disease

Question 23

What is IL-6 and what role does it play in CHF?

Answer 23

IL-6 is a cytokine and is high in pts. with severe CHF and cardiogenic shock, and may contribute to further deleterious immune activation responses

Question 24

What are the clinical manifestations of left heart failure a result of and what are they?

Answer 24

Left heart failure symptoms are a result of pulmonary vascular congestion and inadequate pefusion of the systemic circulation. Pts. may present with:

• Dyspnea
• Orthopnea - shortness of breath lying flat - need pillows
• Cough of frothy sputum
• Fatigue
• Decreased urine output
• Edema

Question 25

How is left heart failure managed?

Answer 25

The treatment is aimed at interrupting the worsening cycle of decreasing contractility, increasing preload and increasing afterload, as well as blocking the neurohumoral mediators of myocardial toxicity.

Question 26

What improves myocardial oxygenation in left sided heart failure?

Answer 26

Oxygen, nitrates, and morphine administration

Question 27

What can help raise BP in hypotensive pts. in left sided heart failure?

Answer 27

IV inotropic drugs which increases contractility to help raise BP

Question 28

What drugs reduces preload in left sided heart failure?

Answer 28

Diuretics reduce preload and ACE inhibitors reduce BOTH preload and afterload by decreasing aldosterone levels and reducing PVR

Question 29

What can improve preload and contractility in left sided heart failure?

Answer 29

Short acting IV beta blockers can reduce mortality | IV adminstration of brain natiuretic peptide (nesiritide) also improves preload and contractility

Question 30

What surgical treatments may help pts. in left sided heart failure?

Answer 30

Acute coronary bypass or PCI

Question 31

What is diastolic HF?

Answer 31

Isolated diastolic HF is defined as pulmonary congestion despite a normal SV and CO

Question 32

What causes diastolic HF?

Answer 32

Decreased compliance of the left ventricle and abnormal diastolic relaxation such that a normal LVEDV results in an increased left ventricular end diastolic pressure (LVEDP)

Question 33

What does the LVEDP in diastolic HF normally result in?

Answer 33

Pulmonary edema

Question 34

What are the major causes of diastolic dysfunction?

Answer 34

Hypertension-induced myocardial hypertropy and myocardial ischemia with resultant ventricular modeling

Question 35

How do pts. with diastolic dysfunction present and what may there be evidence of?

Answer 35

Present with dyspnea on exertion, fatigue, evidence of pulmonary edema (rales on auscultation, pleural effusions). There may also be evidence of underlying coronary disease, hypertension, or valvular disease

Question 36

How is diastolic dysfunction diagnosed by?

Answer 36

ECG demonstrating poor ventricular filling with normal ejection fractions

Question 37

What can right HF result from and what happens?

Answer 37

Right HF can result from left HF when the increase in left ventricular filling pressure that is reflected back into the pulmonary circulation is severe enough. As pressure in pulmonary circulation rises, the resistance to right ventricular emptying increases. The right ventricle is poorly equipped to handle this increased workload, will dilate and fail.

Question 38

What happens when right ventricle begins to fail in right HF?

Answer 38

Pressure will rise in the systemic venous circulation which results in peripheral edema and hepatosplenomegaly

Question 39

What is high-output failure?

Answer 39

It is the inability of the heart to adequately supply the body with blood borne nutrients, despite adequate blood volume and normal or elavated myocardial contactility

Question 40

What are common causes of high-output failure?

Answer 40

Anemia Septicemia Hyperthyroidism Beriberi

Question 41

What does anemia do?

Answer 41

Decreases the oxygen-carrying capacity of the blood Metabolic acidosis occurs as body cells switch to anaerobic metabolism and in response to the acidosis the HR and SV increase in an attempt to circulate blood faster

Question 42

What happens if anemia is severe?

Answer 42

Maximum CO will be unable to supply cells with enough O2 for metabolism = bad

Question 43

What is septicemia?

Answer 43

Disturbed metabolism, bacterial toxins, and the inflammatory process cause systemic vasodilation and fever - the heart may not be able to increase CO enough to compensate for vasodilation. Body tissue will show signs of inadequate blood supply despite a very high CO

Question 44

What does hyperthyroidism do?

Answer 44

Accelerates cellular metabolism through the actions of elevate levels of thyroxine from the thyroid gland which may occur chronically (thryotoxicosis) or acutely (thyroid storm)

Question 45

What is beriberi?

Answer 45

Thiamine deficiency usually caused by malnutrition secondary to chronic alcoholism. It impairs cellular metabolism in all tissues, including the myocardium

Question 46

What does the treatment of CHF focus on?

Answer 46

Treating the symptoms and signs of CHF and preventing disease progression . If there is a reversible cause then obviously address that. Reversible cause treatments can include exercise, eating healthy foods, reduction in salty foods, and abstinence of drinking/smoking

Question 47

What are non-pharmacologic methods for CHF treatment?

Answer 47

Moderate physical activity Weight reduction Sodium restriction Fluid restriction

Question 48

What are drugs used to treat CHF?

Answer 48

``` Diuretic agents Vasodilator agents Positive inotropes ACE inhibitors Beta blockers Aldosterone antagonists ```

Question 49

What would pts. with NYHA class III or IV, left ventricular ejection fraction <35% or less, and a QRS interval of 120ms or less benefit from?

Answer 49

CRT - cardiac resynchronization therapy - pacing both the left and right ventricles - through bi-ventricular pacemaker or surgical remodeling of the heart