Week 8 Flashcards
Heart failure is a disease with two major forms:
- Heart failure with left ventricular systolic dysfunction
- Diastolic heart failure
How is HF characterized?
HF is a progressive, often fatal disorder characterized by ventricular dysfunction, reduced cardiac output, insufficient tissue perfusion, and signs of fluid retention (e.g., peripheral edema, shortness of breath)
Drugs recommended for Heart Failure:
- diuretics,
- inhibitors of the renin-angiotensin-aldosterone system (RAAS),
- beta blockers, and
- digoxin
HF
HF is a syndrome in which the heart is unable to pump sufficient blood to meet the metabolic needs of tissues.
Underlying causes of HF
- Chronic hypertension
- Myocardial infarction
What is the initial phase of heart failure?
In the initial phase of failure, the heart undergoes remodeling, a process in which the ventricles dilate (grow larger), hypertrophy (increase in wall thickness), and become more spherical (less cylindrical).
High-output failure
High-output failure is the inability of the heart to adequately supply the body with blood-borne nutrients, despite adequate blood volume and normal or elevated myocardial contractility.
Common causes of high-output failure
Common causes of high-output failure are anemia, septicemia, hyperthyroidism, and beriberi
Drugs for heart failure
Diuretics
RAAS inhibitors
Beta Blockers
Digoxin
Dopamine
Hydralazine
RAAS inhibitors for Heart Failure:
Angiotensin-converting enzyme inhibitor
Angiotensin II receptor blockers
Aldosterone antagonists
Direct Renin inhibitors
What are diuretics for?
Diuretics are first-line drugs for all patients with signs of volume overload or with a history of volume overload.
By reducing blood volume, diuretics do what?
By reducing blood volume, these drugs can decrease venous pressure, arterial pressure (afterload), pulmonary edema, peripheral edema, and cardiac dilation.
What happens if excessive diuresis occurs?
If blood volume drops too low, cardiac output and blood pressure may fall precipitously, thereby further compromising tissue perfusion.
Types of Diuretics for Heart Failure:
Thiazide Diuretics
Loop Diuretics
Potassium Sparing Diuretics
Thiazide diuretics:
Thiazide diuretics (e.g., hydrochlorothiazide) produce moderate diuresis.
oral agents are used for long-term therapy of HF when edema is not too great.
Principle adverse effect of Thiazides
The principal adverse effect of thiazides is hypokalemia, which increases the risk of digoxin-induced dysrhythmias
Why are loop diuretics the drug of choice for severe HF?
Because they can mobilize large volumes of water and because they work when GFR is low, loop diuretics are drugs of choice for patients with severe HF.
Loop diuretics for Heart Failure
Loop diuretics (e.g., furosemide) produce profound diuresis.
Loop diuretics can cause what issues?
- These drugs can cause hypokalemia, thereby increasing the risk of digoxin toxicity.
- loop diuretics can cause severe hypotension secondary to excessive volume reduction.
Shock
In shock the cardiovascular system fails to perfuse the tissues adequately, resulting in widespread impairment of cellular metabolism.
What does shock progress to?
shock progresses to organ failure and death
multiple organ dysfunction syndrome (MODS)
multiple organ dysfunction syndrome (MODS) describes the failure of two or more organ systems after severe illness and injury and is a frequent complication of severe shock.
In all types of shock what happens to cells?
In all types of shock, the cell either is not receiving an adequate amount of oxygen or is unable to use oxygen.
Types of shock:
cardiogenic (caused by heart failure),
hypovolemic (caused by insufficient intravascular fluid volume),
neurogenic (caused by neural alterations of vascular smooth muscle tone),
anaphylactic (caused by immunologic processes), or
septic (caused by infection).
Cardiogenic shock
Cardiogenic shock is defined as decreased cardiac output and evidence of tissue hypoxia in the presence of adequate intravascular volume.
