Week 8: Chp 30: Heart Failure Flashcards
Heart failure is more common in?
- age >65
- African Americans
- overweight
- people who have had a heart attack
Risk Factors associated with development
-Coronary Artery Disease (CAD)
-Hypertension
-Diabetes Mellitus
-Metabolic Syndrome
-Obesity
-Smoking
-High Sodium Dietary Intake
>other conditions: valvular dysfunction; cardiomyopathies; infectious and inflammatory heart disorders such as pericarditis and endocarditis, dysrhythmias, and cardiotoxic substance exposure, such as alcohol, chemotherapy, and illicit drugs
Other conditions that can cause HF
- valvular dysfunction
- cardiomyopathies
- infectious and inflammatory heart disorders such as pericarditis and endocarditis
- dysrhythmias
- cardiotoxic substances such as alcohol, chemotherapy, and illicit drugs
What is Heart Failure?
progressive disease characterized by myocardial cell dysfunction, resulting in the inability of the heart to pump enough cardiac output to meet the demands of the body
Pathophysiology
- normal physiology of the heart is governed by the Frank-Starling Law, which states that the contractility of the myocardial muscle is influenced by the amount of blood within the ventricle prior to systole; in other words, high end diastolic volume stretches the myocardium, increasing the force of each contraction
- in people with risk factors for HF, such as hypertension, the constant demands on the myocardial muscles over time cause them to become weakened and unable to pump effectively
What is activated in response to decreased stroke volume and cardiac output?
compensatory mechanisms
-these responses are actions that enable the body to maintain function
Compensatory mechanisms
actions that enable the body to maintain function
- activated in response to decreased stroke volume and cardiac output
- SNS and neurohormonal compensatory Reponses
Compensatory Mechanism: Sympathetic Nervous System
the SNS releases epinephrine and norepinephrine, resulting in an increased heart rate, increased myocardial contractility, and increased vasoconstriction in an effort to increase cardiac output
- this additional workload stimulates ventricular remodeling, which results in hypertrophy or stiffening of the ventricular walls
- long-term effects of SNS responses are damaging; they produce an increase in cardiac workload and cardiac oxygen consumption, worsening the failure
Compensatory Mechanisms: Neurohormonal compensatory response: renin-angiotensin-aldosterone system (RAAS)
- this is done in reaction to decreased blood flow to the kidneys
- the kidneys interpret this as decreased volume and release an enzyme, renin
- renin converts angiotensin, an inactive peptide released by the liver, to angiotensin I
- Angiotensin I is enzymatically converted to angiotensin II by angiotensin-converting enzyme released by the lungs
- Angiotensin II produces peripheral vasoconstriction, which helps increase blood pressure and venous return to the heart
- Angiotensin II also stimulates the release of aldosterone from the adrenal cortex, which results in sodium and water retention
- mechanism is effective in the short-term, but in the long term, they overtax an already weak heart with increased volume and workload
Angiotensin II produces?
peripheral vasoconstriction
-can increase BP and venous return to the heart
The release of aldosterone can result in?
sodium and water retention (where sodium goes, water goes)
Compensatory Mechanisms: Neurohormonal response: Natriuretic peptide
Brain natriuretic peptide, or B-type natriuretic peptide (BNP, is a hormone produced by the ventricular cardiac muscle
- it is released in reaction to “overstretching” of the ventricle in response to increased pressure and volume
- the result is a natural diuresis as well as arterial and venous dilation
- this action decreases both preload and afterload, which decreases the workload on the heart
What hormone is produced by the ventricular cardiac muscle and is released in reaction to “over stretching” of the ventricle in response to increased pressure and volume?
BNP (brain natriuretic peptide/ B-type natriuretic peptide
-results in natural diuresis as well as arterial and venous dilation; decreases both preload and afterload decreasing the workload of the heart
Heart Failure is Classified based on?
> ejection fraction
-percentage of blood that is ejected from the ventricle with each contraction
Ejection Fraction
percentage of blood that is ejected from the ventricle with each contraction
- normal: 55 to 70% of the total volume
- this is how heart failure is classified
Ejection Fraction ranges
- (HFrEF): patient with low EF have HF and reduced EF; systolic heart failure; have weakened contractions with an EF of 45% or less
- (HFpEF): patients with clinical manifestations of HF but an EF of greater than 45% are diagnosed with HF with preserved ejection fraction (EF); diastolic HF; inability of the ventricles to fill
HF is described according to?
- ejection fraction
- anatomical dysfunction
- disease progression
- and severity of symptoms
Biventricular failure
when both sides of the heart are affected
Left-sided HF
dysfunction of the left ventricle
Right-sided HF
inability of the right side of the heart to effectively pump blood to the pulmonary vasculature
Common signs of HF
-fatigue
-weight gain
-faster heart rates
-and hypo or hypertension
>heart murmur may be present if the cause of HF is valve dysfunction
>when auscultating heart tones, a third sound S3 may be a warning sign of worsening heart failure
-S4 is common in chronic HF
>the point of maximal intensity may be enlarged or displaced when ventricles enlarge
Left-Sided HF clinical manifestations
the weakened contraction results in poor peripheral perfusion and backflow of blood that causes fluid accumulation in the lungs
- SOB (dyspnea), orthopnea, fatigue, and crackles heard on auscultation
- pale color, weak pulses, cool temperature in extremities, delayed capillary refill
- fatigue, weakness
Right-Sided HF clinical manifestations
the weakened contraction of the right ventricle, results in backflow of blood into the right atrium and venous circulation
- jugular vein distention (JVD)
- generalized dependent edema
- hepatomegaly (enlarged liver)
- ascites (abdominal swelling)
Diagnosing of HF
dependent on history and physical assessment
-symptoms are nonspecific so diagnostic tests are done to rule out other disorders and determine the underlying cause
Diagnostic Tools
- chest x-ray, echocardiogram, and ECG to assess the presence of structural disease, ejection fraction, heart size, pulmonary congestion, or dysrhythmias
- multigated acquisition (MUGA) scans can also determine ejection fraction (EF)
- nuclear imaging studies, stress testing, and coronary angiography to evaluate blood flow to the heart are performed when coronary artery disease is suspected
Diagnostic Tests: Laboratory Tests
- cardiac biomarkers
- serum electrolytes
- CBC
- urinalysis
- glucose level
- fasting lipid profile
- liver function testing
- renal function test
Laboratory Tests: Serum electrolytes
electrolytes can be outside the normal range as a result of decreased kidney perfusion or medication
-Ex: potassium might be low because of diuretic therapy
Laboratory Tests: Renal Function
inadequate flow to the kidneys may impair renal function, resulting in elevated creatinine and blood urea nitrogen (BUN) levels
Laboratory Tests: CBC
decreased hemoglobin and hematocrit levels may indicate anemia, which may be a result of decreased blood flow to the kidneys that reduces the production of erythropoietin in the kidneys
Laboratory Tests: Cardiac Biomarkers
such as Troponin I or T, are used to rule out an acute ischemic event
-BNP and N-terminal pro-B-type natriuretic peptide (NT-proBNP), are increased because of the overstretching of the ventricles
>increased values in these tests can be used to diagnose HF
>BNP and NT-proBNP can also guide clinical decision making and track a patients response to therapy as well as indicate disease progression
Goal of HFrEF management
reduction of risk factors, manipulation of the critical components of cardiac output (preload, afterload, contractility), and control of the compensatory mechanisms
What does successful management do?
slows disease progression, prevents complications, reduces morbidity and mortality, and improves quality of life
Risk factor management may include
- blood pressure and glucose control
- weight loss
- optimizing serum lipids
- smoking cessation
Medications: Beta Blockers
beta blockers are used to control the sympathetic nervous system compensatory response in HF, such as tachycardia, in order to decrease cardiac workload
Medication: Ivabradine
a new medication that slows sinus-node firing, can be added for greater control of heart rate in patients taking maximal doses of beta blockers or who do not tolerate beta blockers
Preload
amount of stretch in the heart at the end of diastole (filling) and is affected by the amount and pressure of blood returning to the heart
-aldosterone antagonists diuretics such as spironolactone (Aldactone) and loop diuretics such as Furosemide (Lasix) are essential medications to decrease preload in patients with fluid retention
Medication: Aldosterone antagonists
spironolactone (Aldactone)
>as well as loop diuretics such as Furosemide (Lasix) are essential medications to decrease preload in patients with fluid retention
>spironolactone should be cautioned in patients with renal insufficiency because of the potential complication of hyperkalemia
>furosemide can cause hypokalemia and is often paired with a potassium replacement therapy