Perfusion: Cardiac Dysrhythmias Flashcards
What is athletic heart syndrome?
When athletes have a lower heart rate because all of their training makes the heart beat more slowly and forcefully.
How does age affect cardiac rhythms?
- The natural pacemaker of the heart loses some of its cells= slower heart rates
- The left ventricle increases in size
- the heart size increases by decreases in filling capacity
How does electrical activity spread through the heart?
SA node (atrium)-> Right and left atrial cells -> Internodal pathways -> Atrioventricular (AV) node -> Bundle of His -> Right and Left bundle branches -> Purkinje Fibers -> Ventricular cells
What is the AV node?
The atrioventricular node
What is the SA node?
The sinus atrial node (pacemaker)
What does the AV node do?
- Delays so that the atria can contract and give an extra bolus of blood to the ventricles
- Controls the number of impulses that reach the ventricles, preventing extremely rapid heart rates
Why do dysrhythmias occur?
Because of anything that could cause a disruption of the electrical activity of the heart.
What can cause ectopic beats?
Abnormal impulses that may originate outside normal conduction pathways
What is an ectopic beat?
impulses that interrupt the normal conductions sequence and may not initiate a normal muscle conduction
What is a heart block?
A block in the normal electrical conduction of the heart
What is MI?
Myocardial Injury
What types of heart blocks are common with acute MI’s
bundle branch blocks
What is a major cause of tachydysrhytmia?
Reentry phenomenon
How does the reentry phenomenon work?
- it is triggered by an ectopic beat
- The impulse is delayed in one area of the heart (area of the ischemia or injury
- Muscle that has been depolarized (activated) by the impulse is repolarized by the time the impulse traveling through the area of slow conduction reaches it.
- Thus, another cycle of depolarization (activation) occurs
What are some types of reentry phenomenons?
atrial dysrhythmias (e.g. atrial flutter, atiral fibrillation)
How are cardiac rhythms classified?
- the site of the impulse formation
2. the site and degree of conduction block
Where do Supraventricular rhythms arise?
above the ventricles
Give some examples of supraventricular rhythms?
- sinus rhythms
- atrial rhythms
- junctional rhythms (arising from the AV junction)
Who are at the most risk for cardiac dysrhythmias?
hx of heart disease:
- CAD
- prior heart surgery
- high BP
- congenital heart disease
- heart attacks
- other heart damage
What other populations are at risk for heart dysrhythmias?
- endocrine issues (thyroid problems, diabetes, and electrolyte imbalances)
- sleep apnea
- alcohol stimulants (caffeine and nicotine)
What are some methods used to increase heart health?
- heart-healthy diet
- moderate physical exercise
- maintaining a healthy weight
- following treatment recommendations
- limiting alcohol and caffeine consumptions
- refraining from tobacco use
- avoid medications that can cause dysrhythmias
What is a Normal sinus rhythm?
The normal heart rhythm
What are the most common symptoms of cardiac dysrhythmias?
- lightheadedness
- dizziness
- fluttering
- a racing or slow heartbeat
- shortness of breath
- chest discomfort or pain
- syncope
What is PAC?
Premature Atrial Contractions
What is PSVT?
Paroxysmal Supraventricular Tachycardia (tachycardia of sudden onset and termination)
What does paroxysmal mean?
occurring in bursts with an abrupt onset and termination
What is atrial flutter?
A rapid and regular atrial rhythm thought to result from an intra-atrial reentry mechanism
What is atrial fibrillation?
Disorganized atrial activity without discrete atrial contractions
What are PVCs?
Premature Ventricular Contractions: ectopic ventricular beats that occur before the next expected beat of the underlying rhythm
What is a couplet?
two PVCs in a row
What is a triplet or salvo?
three consecutive PVCs in a row
What is ventricuar bigeminy?
A PVC following each normal beat
What is ventricular trigeminy?
A PVC noted every third beat
What is Ventricular Tachycardia?
Rapid ventricular rhythm define as three or more consecutive PVCs
What is another name for Ventricular fibrillation?
Cardiac arrect
What are the clinical manifestations of Decreased Cardiac Output?
- changes in LOC ranging from dizziness to complete loss of consciousness
- ischemia
- Reduced tissue perfusion
- hypotension
What are the clinical therapies for Decreased CO?
- administer antidysrhythmic medications
- perform defibrillation or cardioversion (external or implanted)
- Install pacemaker (external or implanted)
- Reduce cardiac workload
What are the clinical manifestations of alterations in oxygenation?
- cyanosis
- SOB
- hypoxemia
- Hypercapnia
- Altered LOC
- Death
What are the clinical therapies for alterations in oxygenation?
- administer oxygen
- provide mechanical ventilation
- Reduce activity to decrease oxygen demands on the body
What are the clinical manifestations of stasis blood in the heart?
- increased risk of emboli formation that manifests differently depending on where the thrombus occurs
- may result in MI, stroke, or DVT
What are the clinical therapies for the stasis of blood in the heart?
- administer anticoagulants
2. treat the underlying dysrhythmia to promote movement of blood through the chambers of the heart
What are the clinical manifestations of sudden cardiac death?
- pulselessness
- absence of respirations
- Death
What are the clinical therapies of Sudden cardiac death?
- perform CPR
- administer antidysrhythmic meds
- administer oxygen
- Conduct cardiorespiratory monitoring after successful resuscitation
What indicates that cardiac monitoring is needed?
- perioperative monitor of heart rate and rhythm
- detecting and identifying dysrhythmias
- Monitoring the effects of cardiac and noncardiac disease on the heart
- Monitoring patients with potentially life-threatening conditions: major trauma (especially cardiac trauma), dissecting aneurysm, acute MI, heart failure, shock, and other emergency conditions
- Evaluating responses to procedures and interventions such as drug therapies, diagnostic procedures, ablative techniques, angioplasty, cardiac catheterization, cardiac surgery, pacemaker function, and automated ICD function
What is the most common type of medication used for dysrhythmias?
antidysrhythmic drugs
What are the nursing considerations to remember before giving antidysrhythmic medications?
- obtain thorough drug and medical history
- measure baseline vital signs
- measure cardiac rhythm
- labs should be reviewed
What are class I antidysrhythmic drugs?
fast sodium channel blockers
What are Class II antidysrhythmic drugs?
beta-adrenergic blockers
What are Class III antidysrhythmic drugs?
potassium channel blockers
What are Class IV antidysrhythmic drugs?
Calcium channel Blockers
What is synchronized cardioversion?
delivery of direct electrical current synchronized with the patient’s heart rhythm
What does a nurse do to help with cardioversion?
- preparing the patient
- obtaining lab tests
- obtaining and documenting ECG strips before, during, and after treatment
- setting up equipment
- monitoring the patient’s response
What are electrophysiology studies?
Diagnostic tests that are used to identify dysrhythmias and their causes as well as treat dysrhythmias
How are electrophysiology procedures conducted?
- electrode catheters are guided by fluoroscopy into the heart through the femoral or brachial veins
- The timing and sequence of electrical activation during normal and abnormal rhythms are observed and measured
Give an example of how electrophysiology procedures can be used to treat dysrhythmia
- stimulating the patient’s heart to a rate faster than that of the tachydysrhythmia to break the cycle
- ablative therapy to destroy the ectopic site
What is the job of the nurse for electrophysiology procedures?
- explain the procedure and expected sensations
- give antianxiety meds or sedatives if needed
- Assist with IV heparin therapy to reduce the risk of thromoembolism
What is defibrillation?
An emergency procedure that delivers an electrical shock to stop ventricular fibrillation and return to a rhythm that promotes cardiac output sufficient to sustain life
What is a pacemaker?
An external or implanted pulse generator used to provide an electrical stimulus to the heart when the heart fails to generate or conduct its own stimulus at a rate that maintains the cardiac output
What are pacemakers used to treat?
- acute and chronic conduction defects (third-degree AV block)
- Bradydysrhythmias and tachydysrhythmias
How can you tell if someone has a pacemaker by their ECG?
They will have a sharp spike before the P wave fr atrial pacing, and a spike before the QRS if being used for ventricular pacing
How could you prevent lead dislodgement of a pacemaker?
examine active and passive fixation mechanisms
How would you prevent a pneumothorax, hemothorax, or air embolism with a pacemaker?
- Use fluoroscopic guidance of the subclavian puncture with careful technique
- Use introducers with hemostatic valves
How would you prevent myocardial perforation during lead placement with a pacemaker?
- consider lead design prior to implantation
- Ensure physician experience
- Examine the patient’s condition
How would you prevent extracardiac stimulation with a pacemaker?
- decrease voltage output or pulse width
2. the pacemaker may need to be reprogrammed or the leads repositioned
How would someone prevent venous thrombosis and superior vena cava syndrome?
- asymptomatic patients are usually not treated. Specific treatment for thrombosis or fibrosis is causative
- Treatment varies from heparin therapy to percutaneous angioplasty or open surgical procedure. Surgery is the last resort
How would twiddler syndrome (leads become displaced due to the pacemaker box) be prevented?
- the size of the pacemaker pocket should be limited, with the device sutured to the fascia
- patients should be instructed not to manipulate device pockets
How would post pacemaker implant pericarditis be prevented?
- use of anti-inflammatory meds
2. consider repositioning pacemaker leads and/or removing them
What are some safety measures that should be taken with patients that have a pacemaker?
- ensure that all electrical equipment in use has a grounded plug; do not use adapters or extension cords
- Encourage the use of battery-powered equipment (electric razor)
- Remove any damaged electrical equipment from the unit, including equipment that has been abused (dropped in liquid, has had liquid spilled on it; has given anyone a shock; frayed, worn, or otherwise damaged electrical cords or plugs; or has evidence of impaired function, hot smell during use, loose knobs
- wear gloves when handling the pacemaker electrodes or wires
- Insulate pacemaker terminals and pacing wires with nonconductive, moisture-proof material
- test the pacemaker battery before use
- Keep a spare pacemaker, cable, batteries, and battery tester available at all times
- Immediately report any apparent deviation from expected pacemaker function
How does an implantable cardioverter-defibrillator work?
- detects life-threatening changes in the cardiac rhythm and automatically delivers an electric shock to convert the dysrhythmia back into a normal rhythm
- can store ECG records of tachycardic episodes
What kind of conditions are ICDs used for?
- Used for survivors of sudden cardiac (SCD)
- patients with recurrent VT
- patients with demonstrated risk factors for SCD
How often must the lithium-powered battery on ICDs be replaced?
Every 5 years
What are cardiac mapping and catheter ablation used for?
to locate and destroy an ectopic focus
What is an ectopic focus?
a cardiac stimulus, or pacemaker, that is located somewhere other than the SA node
How is cardiac mapping performed?
- A site of earliest impulse formation in the atria or ventricles is identified
- Intracardiac and extracardiac catheter electrodes and computer technology are used to pinpoint the ectopic site on a map of the heart
- the catheters can deliver the ablative (destroying) intervention
How does ablation work?
- it destroys, removes, or isolates an ectopic focus
- radio-frequency energy produced by high frequency alternating current is used to create heat as it passes through tissue
What conditions are catheter ablation used to treat?
- SVTs
- atrial fibrillation and flutter
- paroxysmal VT
What is usually given after catheter ablation?
anticoagulant therapy to reduce the risk of clot formation at the ablation site
What are some other treatments used to treat dysrhythmias?
Vagal maneuvers that stimulate the parasympathetic nervous system (Carotid sinus massage and Valsalva maneuver)
How does the carotid sinus massage work?
It excessively slows the heart rate and is only performed by a physician during continuous cardiac monitoring
How does the Valsalva maneuver work?
It increases intrathoracic pressure and vagal tone, slowing the pulse rate
When do tachydysrhythmias typically occur with children?
- hypoxia
- anemia
- hypovolemia
- shock
- hyperkalemia or hypokalemia
- hyperthyroidism
- catecholamine meds
- stimulant or illicit drug use
What are the most common causes of bradycardia in children?
- vagal stimulation
- metabolic imbalances
- hypoxia
- hypothyroidism
- hypothermia
- AMI
What are the symptoms of dysrhythmias in infants?
- irritability
- paleness
- difficulty feeding or eating
What are the sx of dysrhythmias in older children?
- lightheadedness
- fluttering feeling in the heart
- weakness
- tiredness
- fainting
- chest pain
- sweating
- SOB
What should children suspected of having dysrhythmias be monitored for?
- LOC, heart rate, VS
- changes in color, weakness, irritability, and feeding patterns (hypoxia)
- abnormal ECG finding, fainting, dizziness, palpitations
What are some nursing interventions for children with dysrhythmias?
- provide support, encourage the parents to promote the child’s normal development between episodes, medication education
- Explain treatment plan/home care
- teach parents on how to take an apical pulse. Parents need to be trained in CPR and use of the Valsalva maneuver
- Telephone #s of emergency medical facilities
- Parents and children with SVT understand to avoid cardiac stimulant drugs such as decongestants
- Describe and provide written instructions about the danger signs indicating an episode
- Prepare the child and family for procedures such as radio-frequency ablation or implantation of a pacemaker or ICD
What is common in pregnancy?
premature atrial beats
What are the sx of sustained dysrhythmias (SVT or PSVT) in pregnant women?
- SOB
- palpitations
- dizziness
Why can dysrhythmias occur in pregnant women?
- hormonal changes
- change is associated hemodynamic, hormonal, and autonomic changes
- changes in circulating blood volume, sleep, and emotion during pregnancy
Pregnant women with what conditions are at risk for dysrhythmias?
congenital heart defects
What are some assessments that should be done for an older adult related to cardiac dysrhythmias?
- ask about hx of cardiovascular disease and current meds
- Ask about sx such as episodes of dizziness, lightheadedness, fainting, palpitation, chest pain, or SOB
- Ask about the relationship between sx such as palpitations and intake of certain foods and caffeine-containing beverages
- Evaluate for other contributing factors, such as smoking or alcohol intake
- inquire about a history of falls, particularly any that occurred without apparent reason
What education should be given to an older patient to reduce the risk of cardiac dysrhythmias and potential adverse consequences of dysrhythmias?
- Emphasize the importance of taking meds as prescribed
- encourage the pt to reduce or eliminate caffeine intake
- Encourage the pt to participate in a smoking cessation program and reduction or elimination of alcohol intake
- Encourage the patient to engage in regular exercise
- Instruct the patient to contact the primary care provider for evaluation of sx such as dizziness, fainting, frequent palpitations, SOB, unexplained falls, or chest pain
