Dr. Piras-Med Surg II-Cardiac Dysrhythmias
turn sync button off and defibrillate
During cardioversion, if the patient becomes pulseless, what do we do?
0.04 seconds
Each tiny block on an EKG represents how many seconds?
Polymorphic Ventricular Tachycardia
Occurs when the QRS complexes gradually change back and forth from one shape, size, and direction to another over a series of beats during v-tach
True
True or False: Heart cells work by themselves, they are not innervated by nerves
False, Q and S waves do not always show up on an EKG
True or False: Q waves and S waves should ALWAYS show up on an EKG
False, the depolarization is the electricity which causes the systole (contraction) so they aren't the same, just related
True or false: depolarization and systole mean the same thing.
Transvenous pacemaker
temporary pulse-generating device that is used to manage transient bradydysrhythmias such as those that occur during acute MIs or after coronary artery bypass graft surgery, or to override tachydysrhythmias
Patient unresponsive, pulseless, apneic
How will a patient experiencing asystole look?
automaticity excitability conductivity contractility
What are the four properties of cardiac cells?
We don't get concerned with these unless they continually happen and then we try to treat the underlying cause first Most of the time these are benign but if they continue then it could turn into a-fib or atrial flutter
Are we always concerned with premature atrial contractions?
More than one lead
Asystole must be assessed in ___________ __________ ___________ ____________.
paroxysmal
Beginning suddenly or abruptly and then goes away
3-5 blocks
How many blocks should the PR interval be between?
(<0.4 seconds)
How many seconds do we like to see the QT interval to last?
Systole or contraction
Depolarization really is saying what?
The PVCs come all in a row for a long string
Describe PVCs and V-tach:
The PVC comes every three beats
Describe Trigeminy PVCs:
Random ectopic foci cause the ventricles to beat early and when the P waves come in early they are widened and bizar appearing
Describe a multifocal PVC:
There is still an irregular rhythm and no p wave so it is still a-fib but the ventricular response is controlled and partially steady. The controlled is referring to any BMP under 100 in a-fib
Describe atrial fib with controlled ventricular response:
The PVC comes every other beat
Describe bigeminy PVCs:
The PVCs come two in a row
Describe couplet PVCs:
The p waves are rhythmic and the QRS waves are rhythmic but the two are not talking to each other as you can see between the spaces which slows the heart rate down and the blood is not completely moving end to end
Describe the appearance of a Third-Degree Heart Block:
The PR interval stays stable but every 2-3 beats the ventricular contraction is blocked and no QRS appears
Describe the appearance of a second-degree AV Block, Type II:
Prolonged PR interval that keeps getting longer and then it disappears (drops a beat or in other words the atria beats but the ventricle does not)
Describe what a Second Degree AV block Type I looks like:
•Consists of a lead system placed via subclavian vein to the endocardium •Battery-powered pulse generator is implanted subcutaneously •Sensing system monitors HR and rhythm - delivering 25 joules or less to heart when detects lethal dysrhythmia
Describe what an ICD does and the placement of it:
Associated with disease states and certain drugs Typically not serious Patients asymptomatic No treatment (unless the PR interval continuously becomes longer and longer) Monitor for changes in heart rhythm
Describes the characteristics of a First-Degree AV Block:
Electrode-tipped ablation catheter "burns" accessory pathways or ectopic sites in the atria, AV node, and ventricles
Explain radiofrequency catheter ablation therapy:
There is a focus above the ventricle, but it isn't from the SA node so it causes the ventricle to contract too many times
Explain what is happening with a paroxysmal supraventricular tachycardia?
Start CPR and get a defibrillator FAST!
For sudden cardiac death, how do we treat it?
0.08-0.12 seconds
How many seconds should the QRS be?
Unresponsive, pulseless, and apneic
How will a patient appear when in V-fib?
They are typically not harmful to a normal heart but CO reduction, angina, and HF can occur with these in a diseased heart
How do PVCs effect a normal heart as opposed to a diseased heart?
They block the action potential of the heart and, in turn, slow the heart down
How do calcium channel blockers work in the heart?
Drugs to control ventricular rate and/or convert to sinus rhythm (amiodarone (K+ channel blocker), diltiazem (Ca+ channel blocker) and ibutilide most common) **bolus then hang a drip Electrical cardioversion Radiofrequency ablation Maze procedure with cryoablation (they freeze the ectopic foci)
How do we treat atrial fibrillation?
The underlying cause needs to be quickly identified and treated CPR followed by intubation and IV epinephrine
How do we treat pulseless electrical activity?
Atropine is given IV push, right away! Pacemaker is put in if it continues Make sure to discontinue drugs that cause low HR (CCB or Beta Blockers)
How do we treat symptomatic bradycardia?
You count the QRS complexes within 1 minute by counting how many R-R intervals there are in 6 seconds then multiply it by 10
How do you calculate the HR from an EKG strip?
It slows the heart down until it blocks right at the AV node and stops it from working
How does adenosine work?
Passage of DC electrical shock through the heart to depolarize myocardial cells Allows SA node to resume pacemaker role
How does defibrillation work?
•HR is 150-220 beats/minute •HR > 180 leads to decreased cardiac output and stroke volume •Hypotension •Dyspnea •Angina
How does paroxysmal supraventricular tachycardia manifest?
Palpitations Heart "skips a beat"
How does premature atrial contraction manifest?
Dizziness Dyspnea Hypotension Angina in patients with CAD
How does sinus tachycardia manifest?
Hypotension Pale, cool skin Weakness, dizziness or syncope Angina Confusion or disorientation Shortness of breath
How does symptomatic sinus bradycardia manifest?
Treat with pacemaker right away!
How is Second Degree AV Block Type II treated?
CPR and ACLS Defibrillation and drug therapy (epinephrine, vasopressin, amiodarone)
How is V-fib treated?
Antidysrhythmics or cardioversion Pronestyl (Na+ Channel Blocker), Amiodarone (K+ Channel Blocker) Lidocaine
How is V-tach with a pulse treated?
Monitor them very closely and watch for symptoms!!
How is a ASYMPTOMATIC patient with Second Degree AV Type I Block treated?
Atropine Pacemaker
How is a SYMPTOMATIC patient with Second Degree AV Block Type I treated?
With a pacemaker and drugs to increase HR if needed while awaiting pacing (atropine is NOT effective in this situation!)
How is a Third Degree AV Heart Block treated?
CPR and ACLS measures (epinephrine and vasopressin) Intubation
How is asystole treated?
Along with the atrial quivering, there is a rapid ventricular response. The ventricles pump so fast along with the atrial quivering that no blood is able to move anywhere in the heart or out of the heart. This is a big problem because the patient cannot get adequate perfusion.
How is atrial fib with RVR different?
There is no definable p wave and irregular R-R waves
How is atrial fibrillation characterized?
Monitor for more serious dysrhytmias Withhold sources of stimulation Beta blockers
How is premature atrial contraction treated?
CPR and rapid defibrillation
How is pulseless V-tach treated?
FIRST treat the underlying cause (Pain, anxiety, fever, dehydration, exercise, caffeine, cardiac problems) Then try vagal maneuver or beta blockers
How is sinus tachycardia treated?
Atrial flutter is one ectopic focus firing in the middle of the ventricles resting, atrial fibrillation can be three hundred to 400 hundred ectopic foci that causes the heart's conduction system to change
How is the electrical firing of atrial fibrillation and atrial flutter different?
40-60
How many beats a minute does the AV node fire?
20-40
How many beats per minute does the His-Purkinje fibers fire?
decrease
ICDs (increase/decrease) mortality.
Couplet PVC
Identify the dysrthymia pictured:
Multifocal PVCs
Identify the dysrthymia pictured:
Ventricular bigeminy
Identify the dysrthymia pictured:
Ventricular trigeminy
Identify the dysrthymia pictured:
ventricular tachycardia
Identify the dysrthymia pictured:
Second Degree AV Block Type I
Identify the pictured dysrhythmia:
Second Degree AV Block Type II
Identify the pictured dysrhythmia:
Torsades de pointes
Identify the pictured dysrhythmia:
V-fib
Identify the pictured dysrhythmia:
V-tach
Identify the pictured dysrhythmia:
Atrial Fibrillation
Identify the pictured rhythm:
Pacemaker Spike (controlled at atria)
Identify the pictured rhythm:
Pacemaker spike (controlled at the ventricles)
Identify the pictured rhythm:
sinus bradycardia
Identify the rhythm from the EKG strip:
Premature Atrial Contraction
Identify the rhythm listed:
normal sinus rhythm
Identify the rhythm on this EKG strip:
Atrial Flutter
Identify the rhythm pictured:
First Degree AV Block
Identify the rhythm pictured:
Paroxysmal Supraventricular Tachycardia (PSVT)
Identify the rhythm pictured:
Sinus Tachycardia
Identify the rhythm pictured:
Supraventricular Tachycardia
Identify the rhythm pictured:
Idioventricular Rhythm
Identify this dysrhythmia:
ventricular fibrillation
Identify this dysrhythmia:
There is no SA node firing
If a P wave does not show up on a EKG, what does this mean?
Usually not, we will ask if this is normal or if they are a runner UNLESS they are symptomatic, then we will be immediately worried
If a patient's HR is 40 with a normal rhythm, will we be immediately worried?
The AV node will pick up the slack, but the HR will be lower than usual because the AV node only fires 40-60 BPM
If the SA node is damaged due to ischemia, what will happen?
Torsades de pointes
Multiple PVC's with rotating ventricular ectopic pacemakers (above) are called:
Dead
PEA = ________
stimulants electrolyte imbalance hypoxia heart disease
PVCs are associated with what?
overexertion, stress, deep inspiration, stimulants, disease, digitalis toxicity
Paroxysmal supraventricular tachycardia is typically associated with what?
Stroke
People with atrial flutter are more at risk for _____________
nonsustained ventricular tachycardia (NSVT)
Relatively brief period (20s or less) in which ventricles contract rapidly on their own as well as in response to AV impulses.
Patient has a pulse Patient is pulseless
Stable V-tach means what? Unstable V-tach means what?
Severe decrease in CO Hypotension, pulmonary edema, decreased cerebral blood flow, cardiopulmonary arrest
Sustained VT causes what? What symptoms are associated?
Ventricular tachycardia with a pulse and supraventricular tachydysrhythmias
Synchronized cardioversion is the choice therapy for what?
Conduction
The P wave is the ___________
atrial depolarization
The P wave represents what?
ventricular depolarization
The QRS wave represents what?
V-tach and V-fib
The majority of sudden cardiac deaths result from what?
A programmable pulse generator (power source) One or more conducting (pacing) leads to myocardium
The pacing circuit of a pacemaker involves what?
Syncope HF Shock
Third Degree AV Heart Block can lead to what?
It results in decreased CO
Third degree AV Heart Block results in what?
Pulseless Electrical Activity
This is a condition in which electrical activity can be observed on the ECG, but no mechanical activity of the heart is evident, and the patient has no pulse
Dysrhythmias
This is a disorder of impulse formation, conduction of impulses, or both
SA node 60-100
This is know as the pacemaker of the heart _______________ How many beats a minute does the pacemaker fire?
Permanent pacemaker
This is when the pacemaker is implanted within the body
monomorphic ventricular tachycardia
This occurs when the QRS complexes that are the same shape, size, and direction in v-tach
Asystole
This refers to total absence of ventricular electrical activity
Sustained ventricular tachycardia
Ventricular Tachycardia (V-Tach) that occurs for more than 30 seconds
MI Ischemia Disease states Procedures
Ventricular fibrillation is often associated with what?
•Stress •Fatigue •Caffeine •Tobacco •Alcohol •Hypoxia (give them oxygen to treat) •Electrolyte imbalance •Disease states
What are some causes of premature atrial contraction?
Caused by vagal inhibition or sympathetic stimulation Associated with physiologic and psychologic stressors Drugs can increase rate
What are some causes of sinus tachycardia?
It is noninvasive, temporary, use lowest current that will capture **patient may need to be sedated
What are some characteristics of a transcutaneous pacemaker?
Failure to sense (Causes inappropriate firing) Failure to capture (Lack of pacing when needed) Infection Hematoma formation Pneumothorax (most of the time with COPD patients) Atrial or ventricular septum perforation Lead misplacement
What are some complications of a pacemaker we and our patients should be aware of?
•Fear of body image change •Fear of recurrent dysrhythmias •Expectation of pain with ICD discharge •Anxiety about going home **Participation in an ICD support group should be encouraged!
What are some feelings we need to consider that our patient may feel after getting an ICD?
•Follow-up appointments for pacemaker function checks •Incision care •Arm restrictions (until told otherwise by their MD) •Avoid direct blows •Avoid high-output generator •No MRIs unless pacer approved •Microwaves OK •Avoid antitheft devices •Travel not restricted •Monitor pulse •Pacemaker ID card •Medic Alert ID
What are some important points for patient and caregiver teaching regarding pacemakers?
1.Follow-up appointments 2.Incision care 3.Arm restrictions (They do not want to typically move their arm around a lot because it could dislodge it but after time scar tissue will build up around the wire as it lays on the heart wall and it will stabilize) 4.Sexual activity (if you can walk a flight of stairs, you are good to go) 5.Driving 6.Avoid direct blows 7.Avoid large magnets, MRI 8.Air travel not restricted 9.Avoid antitheft devices 10.What to do if ICD fires 11.Medic Alert ID 12.ICD identification card 13.Caregivers to learn CPR
What are some patient and caregiver teaching topics we need to cover with a patient with an ICD?
It may result from drugs or CAD but is typically associated with ischemia
What are some reasons for a Second-Degree AV Block Type I?
Clip excessive hair on chest wall Rub skin with dry gauze May need to use alcohol for oily skin Apply gel electrode pad
What are some things that are needed to prepare a patient for an EKG?
Usually result of advanced cardiac disease, severe conduction disturbance, or end-stage HF
What are the causes of asystole usually?
1.Start CPR while obtaining and setting up defibrillator 2.Turn on and select energy 3.Make sure sync button is turned off 4.Apply gel pads 5.Charge 6.Position paddles firmly on chest 7.Ensure "All clear"!!!!! 8.Deliver charge
What are the steps before using a defibrillator?
When the PR interval is greater than 0.2 (or one block)
What determines a first degree AV block?
Repolarization
What do the isoelectric lines represent?
activity of charged ions across membranes of myocardial cells
What do the waveforms of ECG represent?
The heart is failing to capture
What does it mean if you are watching the monitor of a patient who has a pacemaker and you only see pacer spikes?
It represents when the purkinje fibers are awaiting ventricular depolarization The current has gone from the SA node to the AV node to bundle of his to the fibers but HAS NOT caused ventricular depolarization
What does the PR interval represent?
It is the amount of time it takes for the ventricles to depolarize and repolarize
What does the QT interval represent?
It represents ventricular repolarization where the heart is resting
What does the T wave represent?
V-fib and pulseless V-tach we defib
What dysrhythmias are shockable rhythms?
severe heart disease, some systemic diseases, certain drugs
What is Third-Degree Heart Block associated with?
Heart disease, electrolyte imbalances, drugs, CNS disorder
What is V-tach associated with?
It is something that blocks the signal travel through the heart, typically due to damage from something like an MI that has occurred directly above a node
What is a heart block?
It is a potassium channel blocker
What is amiodarone?
Atrial fibrillation
What is considered the most common dysrhythmia?
Graphic tracing of electrical impulses produced by heart
What is electrocardiogram monitoring?
Always look for clots via echocardiogram before treating them because if we kick them back into normal sinus and there was a clot then we have just moved that clot
What is important to check before treating atrial fibrillation?
60-100 BMP and follows normal conduction pattern
What is meant by normal sinus rhythm?
The rate is less than 60 BMP but it follows normal conduction system
What is meant by sinus bradycardia?
That the R wave will hit on the T wave where the heart is trying to rest because it will throw the heart into V-fib
What is the BIGGEST fear we have with PVCs?
Contraction originating from ectopic focus in atrium in location other than SA node Travels across atria by abnormal pathway, creating distorted P wave May be stopped, delayed, or conducted normally at the AV node
What is the cause of premature atrial contraction?
•With cardioversion you must sync it with the person's rhythm! You DO NOT WANT TO SHOCK ON A T WAVE. •Cardioversion is the same concept as defib but it is controlled •Versed is given with the cardioversion procedure to sedate them
What is the difference between defibrillation and cardioversion?
It causes a decrease in CO and an increased risk of stroke
What is the main issue with atrial fibrillation?
Assess and treat the patient, not the monitor!
What is the most important thing to remember with telemetry readings?
•OOB once stable •Limit arm and shoulder activity •Monitor insertion site for bleeding and infection •Patient teaching important (full list of teaching on other slide)
What is the postprocedure protocol for pacemakers?
0.12-0.20 seconds
What is the range of a normal PR interval?
Correct the cause (oxygen, correct electrolyte imbalance, especially K+) Antidysrhythmics (Pronestyl) or amiodarone
What is the treatment for PVCs?
•Vagal stimulation (tell them to bear down, massage the carotids to stimulate the vagus nerve) •IV adenosine (this is the drug of choice because it slows down or stops the AV node from working) •IV β-blockers (sotalol) •Calcium channel blockers (diltiazem) •Amiodarone •DC cardioversion
What is the treatment for SVT?
Pharmacologic agent: beta-blocker, calcium channel blocker (Diltiazem), amiodorone, ibutilide (Corvert) Electrical cardioversion Radiofrequency ablation
What is the treatment for atrial flutter?
It is used to pace the heart when the normal conduction pathway is damaged
What is the use of a pacemaker?
Vagus nerve It is stimulated by coughing, defecating, massaging the carotids, anything that causes increase abdominal pressure
What nerve is responsible for slowing down HR upon stimulation? How can it be stimulated?
Sodium channels
What part of the heart does Corvert work on?
They must be monitored in the ER or ICU and it is IV push by 20 militers of saline to push it directly up to the heart
What precautions do we need with adenosine?
Normal rhythm in aerobically trained athletes may have sinus bradycardia Sleep may cause sinus bradycardia Can occur in response to parasympathetic nerve stimulation and certain drugs Also associated with some disease states
What would be some reasons a patient presents with sinus bradycardia?
Most pace on demand, firing only when HR drops below preset rate because there is a sensing device that inhibits the pacemaker when the HR is adequate and then the pacing device is triggered when no QRS complexes are seen within a set time frame
When do most pacemakers fire?
When completed within 2 minutes of dysrhythmia onset
When is defibrillation most effective?
It is caused by sympathetic stimulation most of the time
Which nervous system is responsible for sinus tachycardia?
contractility
Which of the four properties of cardiac cells represents HR?
•Have survived SCD •Have spontaneous sustained VT •Have syncope with inducible ventricular tachycardia/fibrillation during EPS •Are at high risk for future life-threatening dysrhythmias
Who would qualify for an Implantable Cardioverter-defibrillator?
We are more concerned here because the blood is being blocked all together from adequately getting into the ventricles to perfuse the body
Why are we more concerned with a second-degree AV block Type I than a first degree?
•Symptoms result from high ventricular rate and loss of atrial "kick" → decreased CO → heart failure
Why do symptoms occur with atrial flutter?
Atropine blocks acetylcholine and therefore blocks the PNS so that way the SNS kicks in and the heart rate rises
Why do we use atropine with symptomatic bradycardia?
The heart rate is too low and cannot adequately perfuse the body
Why is Second Degree AV Block Type II concerning?
There is a left atrial appendage that stores extra blood and that blood just stays in there and clots, then it breaks out and causes a stroke
Why is atrial fibrillation more likely to cause a stroke than a PE?
Atrial flutter usually turns into a-fib Additionally, since the focus comes from somewhere else then the atria are not stimulated like they would from the SA node, so the atria loses the 30% that is pushed out with that last kick
Why is atrial flutter a worry?
It will move up and down depending on what the heart is doing or what is wrong with the heart For example, the ST wave will move up with an MI or ischemia
Why is the ST interval important to pay attention to?
Because of decreased CO and the possibility of deterioration to ventricular fibrillation
Why is v-tach considered life-threatening?
We won't typically see a p wave most of the time
Will we see a P wave most of the time in paroxysmal supraventricular tachycardia?
Apical-radial pulse deficit, which means sometimes you will hear the pulse apically but will not feel the pulse radially
With PVCs, what is important to assess?
The R wave of the QRS
With cardioversion, what are we trying to deliver a shock on?
The sync button
With synchronized cardioversion, what button do we use that we do not use in V-fib?
contractility
________________ relies on conductivity
Transcutaneous pacemaker
external pacemaker used as a temporary emergency measure for maintaining adequate heart rate
Epicardial pacemaker
lead or leads are passed through the chest wall from an external power source and attached to the epicardium overlying the atrium or ventricle
