Heart Failure and Atrial Fibrillation Flashcards
How many people over 40 have heart failure in their lifetime?
1 in 5
What increases the prevalence of heart failure?
Age
What are the two primary risk factors for heart failure?
- coronary artery disease
2. hypertension
What is heart failure?
An abnormal condition involving impaired cardiac pumping/lifting
With heart failure, the heart is unable to produce adequate ____?
cardiac output (CO)
What does decreased cardiac output result in?
Decreased perfusion and therefore decreased oxygenation to the body
What are some of the causes of heart failure?
- acute MI and CAD
- dysrhythmias
- infection (endocarditis, myocarditis)
- hypertension
- pulmonary disease
What is preload?
- the volume of blood in the ventricle at the end of diastole, before the next contraction
- determines the amount of stretch placed on the myocardial fibers
- too much stretch, unable to pump effectively
What is afterload?
- the peripheral resistance against which the left ventricle must pump
What is myocardial contractility?
- the ability of the heart muscle to contract and move blood to the lungs or body
- can be impacted by electrolyte levels (calcium) and myocardial oxygen supply
What is heart rate?
- amount of blood that is circulated is impacted by the rate in which the ventricles contract
- lower blood volumes can increase heart rate which increases the workload on the heart
- heart failure patients have a decrease in heart’s ability to pump which causes a decrease in cardiac output
What is cardiac output?
- the amount of blood pumped by each ventricle in 1 minute
- CO = heart rate X stroke volume
- normal range is 4-8 L/min for adults at rest
What is stroke volume?
- the volume of blood pumped from the left ventricle per beat
- ## calculated from ventricle measurements taken from an echocardiogram
What is ejection fraction?
- the measurement of the percentage of blood leaving the heart each time it contracts
- normal range is 50-70%
- patient’s with heart failure often have decreased ejection fraction (impaired left ventricle function = decreased cardiac output)
What is the term used for when the heart makes up for heart failure by activating the sympathetic nervous system?
Compensation
What hormone is released in response to a decrease in cardiac output?
Epinephrine
What does epinephrine do to compensate for heart failure?
- increases heart rate
- increases cardiac contractility
- vasoconstriction
What does long term heart compensation increase?
The workload of the heart (worsening left ventricle performance
What does decreased cardiac out put do to the kidneys?
Causes less blood flow to the kidneys (normally 40% CO)
What system do the kidneys activate when cardiac output decreases and there is less blood flow to the kidneys
RAAS system
What does activating the RAAS system do?
Results in vasoconstriction and sodium and water retention
What receptor in the brain and what part of the brain detects decreased cardiac output and decreased blood flow to the brain?
Osmoreceptors in the hypothalamus
What does activation of the osmoreceptors in the hypothalamus trigger?
Triggers the posterior pituitary to release antidiuretic hormone (ADH)
What does ADH hormone?
Increases water reabsorption in the renal tubules which leads to fluid retention and increased blood volume
What is ventricular dilation a result of?
compensation
What is ventricular dilation?
- decreased CO—> compensation —> increased CO
- increased pressure in left ventricle causes enlargement of the chambers of the heart
- initially an adaptive mechanism
- too much stretch in the ventricle = reduced ability of the myocardium to contract
What is hypertrophy a result of?
Compensation
What is hypertrophy?
- when there is chronic dilation (from increased pressure), it causes an increase in muscle mass and cardiac wall thickness
- causes poor contractility
- higher O2 needs
- poor coronary artery circulation
- risk for ventricular dysrhythmias
What are natriuretic peptides?
Hormones produced by the heart muscle in response to increase atrial and ventricular blood volumes (compensation)
What are the two types of natriuretic peptides?
- atrial natriuretic peptide (ANP)
2. B-type natriuretic peptide (BNP)
What do natriuretic peptides do?
- promote venous and arterial vasodilation, reducing preload and afterload
- increase glomerular filtration = diuresis
Does chronic heart failure lead to a surplus or depletion of natriuretic peptides?
Depletion
What is the normal value for B natriuretic peptide (BNP)?
< 100mcg/L
Is left sided or right sided heart failure more common?
Left (left ventricular dysfunction)
Where does blood back up into in left sided heart failure?
The lungs
What are the signs of left sided heart failure?
- shortness of breath, tachypnea
- cough, restlessness, fatigue
- exertional dyspnea, cyanosis
What is right sided heart failure caused by?
- left sided heart failure
- right ventricular injury (MI)
Where does blood back up into in right sided heart failure?
The venous systemic circulation
What are the signs of right sided heart failure?
- jugular venous distension (JVD)
- hepatomegaly, splenomegaly, anorexia, GI discomfort
- dependent peripheral edema weight gain
What are the diagnostic tests for heart failure?
- echocardiogram
- chest x-ray
- ECG
- lab studies
- stress test
What does an echocardiogram measure?
The ability to pump; calculate ejection fraction
What does a chest x-ray look at?
Lung status
What does an ECG measure?
Rate and rhythm
What do lab studies look at for heart failure?
- cardiac enzymes
- BNP
What does a stress test measure?
Cardiac function
What does decompensated heart failure often manifest as?
Pulmonary edema
What is pulmonary edema?
Abnormal and life threatening accumulation of fluid in the alveoli and interstitial spaces of the lungs
What are some early signs of pulmonary edema?
- mild increase in respiratory rate
- decrease in pulse oximetry (SpO2) levels
What are some nursing interventions for decompensated heart failure?
- place patient in high Fowlers position
- provide supplemental oxygen
- diuretics (furosemide, monitor potassium levels)
- morphine sulfate can decrease myocardial oxygen demands (monitor for respiratory depression)
- reduce anxiety (monitor for sedation)
- frequent focused respiratory and cardiac assessments
- strict intake and output monitoring
What do the signs and symptoms of heart failure depend on?
- the patient’s age
- extent of the disease
- type pf heart failure (right vs left)
- any co-morbidities
What should be included in a nursing assessment for heart failure?
- past health history
- risk factors; MI, hypertension, valve disorders
- family history of heart disease
- functional health patterns (ability to do ADL’s (fatigue), changes over time (last 6 months))
- medications (use of diuretics, OTC, herbal remedies)
What are some early signs of heart failure?
- fatigue after activities that are normally not tiring
- dyspnea with mild exertion or at rest
- orthopnea (SOB when lying down)
- paroxysmal nocturnal dyspnea (wakes patient at night with feelings of suffocation)
- cough (begins as a dry cough, not relieved by position change) (an attempt to open airways and improve oxygenation)
What are some other signs and symptoms of chronic heart failure?
- tachycardia
- edema; peripheral edema (lower extremities), abdomen (ascites), weight gain 3-4 lbs over 2 days = exacerbation of HF
- nocturia (cardiac workload is lessened at night = increased perfusion to the kidneys = diuresis
- skin changes (skin may appear dusky; hair growth diminished, chronic swelling leads to pigment changes
What are the later stages of chronic heart failure?
- restlessness, confusion
- inability to concentrate (poor gas exchange)
- chest pain (angina) (decreased coronary artery perfusion - poor cardiac output)
How do thiazide diuretics work?
- they inhibit sodium reabsorption in the tubules which promotes water loss
- potassium and magnesium loss
How do loop diuretics work?
- promotes sodium, chloride, and water secretion in the ascending loop of Henle
What interventions need to be done when a patient is on diuretics?
- I & O
- daily weights
- electrolyte monitoring
What do ACE inhibitors do?
- inhibit the conversion of angiotensin I to II which prevents vasoconstriction
- less pressure in the vascular system, easier for the heart to pump
What needs to be monitored when a patient is taking ACE inhibitors?
- BP and renal function
- potassium levels
Name two ACE inhibitors:
- ramipril
2. lisinopril
What do Neprilysin inhibitors do? (sacubitril)
- cause an increase in levels of natriuretic peptides
- ANP’s are synthesized and secreted by cardiac muscle cells (which also contain volume receptors)
- ANP is released into the bloodstream via capillary beds when the atria is stretched due to increases in fluid volume
- the ANP then triggers the kidney to excrete sodium which results in fluid loss
- effect is reduction in blood pressure and fluid volume
What needs to be monitored when patients are taking Neprilysin inhibitors?
- blood pressure
- I & O and weight monitoring
- Na+ and K+ levels
What do B-adrenergic blockers do?
- blocks stimulus from the SNS
- reduces heart rate and allows the heart to increase its ability to contract = more output
Name 2 B-adrenergic blockers?
- Carvedilol
2. Metoprolol
What needs to be monitored when a patient is taking B-adrenergic blockers?
- hypotension
- bradycardia
- bronchospasm
- frequent vital signs initially
How much should fluid intake be restricted to with heart failure?
1.5-2L/day
What nutritional changes should be made for heart failure patients?
- stop using salt shaker
- do not add salt to food during preparation
- choose low sodium options
- eat fresh fruits and vegetables
- avoid prepared and processed foods
What time of day should daily weights be taken?
First thing in the morning
What is a synchronized cardioversion?
A device that helps get the heart back in rhythm
What is a pacemaker?
A device that helps regulate heart rate, prevents tachycardia, and maximizes medication therapy
An ejection fraction of _____ or less can lead to myocardial ischemia:
35%
What device can be used in heart failure patients with a low ejection fraction who are at increased risk of ventricular dysthymias?
An implantable cardioverter defibrillator (ICD)
What is an implantable cardioverter defibrillator?
- a lead system that is placed via the subclavian vein to the endocardium
- monitors the patients heart rate and rhythm and will identify abnormal ventricular rhythms such as ventricular tachycardia (VT) and or ventricular fibrillation (V-fib)
- detects abnormal ventricular rhythm and it will send a 25 joules of electricity (shock) to the heart to reset the heart back to the normal rhythm
What is the patient teaching for someone with a ICD or a pacemaker?
- monitor the site for signs of infection
keep the incision dry for 1 week post procedure - avoid lifting the operative site for 1 week (will lift the leads off the heart)
- avoid direct blows to the ICD site
- do not drive until cleared by your physician
- if ICD fires; lie or sit down, if you are feeling unwell or have repeated firing, contact your physician and or go to the ER
What are cardiac dysrhythmias?
Abnormal heart rhythms that affect the ability of the heart to effectively pump oxygenated blood throughout the body
Can cardiac dysrhythmias be life threatening?
Yes
What happens when the heart can not pump effectively?
- perfusion to vital organs and peripheral tissue can be impaired
- oxygenation and perfusion problems
What type of cells regulate the heart’s rhythm and possess unique properties
Myocardial cells
What is automaticity?
Ability of cardiac cells to generate an electric impulse spontaneous and repetitively (pacing function)
What is excitability?
The ability of non-pacemaker heart cells to respond to an electrical impulse and depolarize (react)
What is depolarization
When the normally negatively charged cells within the heart muscle develop a positive charge
What is conductivity?
The ability to send an electrical stimulus from cell membrane to cell membrane
What is the result of conductivity?
Excitable cells depolarize in a rapid succession; sees as a P wave and a QRS complex on a ECG recording
What is contractility?
The ability of the atrial and ventricular muscle cells to shorten their fiber length in response to electrical stimulation (the muscle contracts and move blood forward through the heart)
Where is the SA node located?
Right atrium
The SA node is the hearts, primary ____?
Pacemaker
What is the SA node reflected as on a ECG?
P wave
What systems are connected with the SA node?
Sympathetic and parasympathetic nervous systems
What happens after the SA node is activated?
Atrial muscle contraction follows
Where is the AV node located?
Beneath the right atrial endocardium between the tricuspid valve and ostium of coronary sinus
What is the zone called in which the AV node is activated?
Transitional zone - impulses slow down (delay)
What interval is the transitional zone reflected on a ECG?
PR interval
What’s an atrial kick?
When the atria contract and the ventricles fill
What systems are connected to the AV node?
Sympathetic and parasympathetic nervous systems
What is the Bundle of His?
- connects the AV node and through the interventricular septum
- right bundle; leads to the apex of right ventricle
- left bundle; leads to the apex of left ventricle
What are the Purkinje cells?
- fibers located on the endocardial surface of both ventricles
- apex to base; threaded through myocardium
- conducts the electrical impulses throughout the ventricles
- lead to ventricle depolarization = muscle contraction
What is a ECG?
- a graphic representation of the heart’s electrical activity
- leads placed on the patient’s chest sense electrical activity and are transmitted to monitor which displays the heart’s electrical rhythm
- direction of the current can have a positive deflection or a negative deflection in relation to the baseline (depends on the placement of the lead)
- 5 lead, 3 lead, and 12 lead systems that are used to diagnose ischemia or rhythm disturbances
What is a normal sinus rhythm?
- originates in the SA nodes
- atrial and ventricular rate is between 60-100 beats/min
- rhythm is regular
- P waves present and consistent (one before each QRS complex)
- PR interval is 0.12-020 seconds and consistent
- QR duration between 0.04-0.10 and consistent
What is bradycardia?
- heart rate is less than 60 bpm
- cardiac output is decreased = perfusion problem
- if patient has an adequate BP then they may be able to tolerate the slow rate (elite athlete)
- if the BP is too low = problems with oxygenation which can lead to myocardial ischemia
What is a permanent pacemaker?
- placed in patient’s with conduction disorders
- the generator is placed in a subcutaneous pocket near right or left subclavian site
- leads follow the cephalic or subclavian veins to the endocardium on the right side of the heart
- pulse sent via leads to the heart to stimulate cells for depolarization
What is sinus tachycardia?
- heart rate is over 100 beats/min
- short cardiac cycle, ventricles do not have time to fill properly, which leads to decreased cardiac output
- short diastolic time which means less time for blood to perfuse the coronary arteries which can lead to increases in heart rate
What happens when cardiac output decreases?
- increased heart rate, decreased bp, decreased urinary output
- diminished pulses, decreased SpO2
- weakness, restlessness, anxiety, and confusion
How to treat tachycardia?
- treat the cause
- frequent vital signs
- supplemental oxygen
- IV access
- cardiac monitor
- medications
- decrease caffeine, nicotine, cocaine, etc…)
What is an atrial dysrhythmia?
- focus of the impulse shifts away from the SA node and is generated from atrial tissues
- changes the depolarization of the tissues and P wave shape is changed (atrial fibrillation)
- most common dysrhythmia; associated with hypertension, heart failure, CAD
- increased risk of stroke, heart failure, thromboembolic events
- risk factors: obesity, advanced age, Caucasian, excessive alcohol use
- multiple rapid impulses from many different foci depolarize the atria in a disorganized manner (rate = 300-600 bpm, resulting in a ventricular response of 120-200 bpm)
- rhythm is chaotic, no clear P waves, no atrial kick (atria quiver which results in a rapid and irregular ventricular rate, decreased filling time, poor cardiac output, poor perfusion)
What is drug therapy used for in patients with atrial fibrillation?
To slow ventricular conduction or to convert to NSR
Name two drugs used to treat atrial fibrillation?
- Cardizem
- bolus and infusion, followed by PO therapy
- calcium channel blocker
- monitor heart rate, bp, and rhythm - Multag
- used to treat chronic A fib
- tolerated better than amiodarone for maintenance
- monitor heart rate and rhythm (bradycardia), shortness of breath
- monitor BUN, CR, and liver enzymes
- take with meals and not with grapefruit juice
Name another drug used for atrial fibrillation and what it does?
Digoxin
- IV for acute and PO for maintenance
- prolongs refractory period in AV node and increases contractility of myocardial contraction = slows heart rate and increases CO
- monitor heart rate
- teach patients to report anorexia, nausea, vomiting, confusion, or vision changes
- monitor potassium levels (hypokalemia results in digoxin toxicity and ventricular dysthymias
What should be known about anticoagulants that are given for atrial fibrillation?
- aspirin or warfarin can be used
- alternatives include; xarelto and eliquis
- patient is to monitor for bleeding in nose or gums and bruising
