4554 Week 6 Part 1
Atrial Flutter
"Saw tooth"- flutter Rouge atrial cells continuous fluttering "4 to 1 conduction"
pulseless and with a pulse
2 kinds of V tach
AV Junctional Blocks
AV Junction can block impulses coming from the SA Node.
paroxysmal
Beginning suddenly or abruptly; convulsive
HR
Count QRS and multiply by 10 to find the...
Multifocal PVCs
Different ventricular cells are depolarizing and the impulses are abnormally conducting through the ventricles. Look different bc they are from diff parts of the ventrical
dysrhythmia
Disorder of impulse formation, conduction of impulses, or both
Second Degree Type I aka Wenckebach
Each successive atrial impulse encounters a longer and longer delay in the AV node until one impulse (usually the 3rd or 4th) doesn't make it through and gets dropped. Going, going, gone... PR interval gets longer then longer then drops a beat
20-40 bpm
His-Purkinje fibers
SNS
Increases rate of SA node Increases impulse conduction of AV node Increases cardiac contractility
12 lead ECG
Looking at the heart from 12 different views
sinus brady
Manifestations (less CO-not as much blood out to body)
Second-Degree AV Block, Type 1 (Mobitz I, Wenckebach)
May result from drugs or CAD Typically associated with ischemia Usually transient and well tolerated Treat if symptomatic Atropine Pacemaker If asymptomatic, monitor closely
AV node, His-Purkinje fibers
Secondary pacemakers
Atrial Flutter
Typically associated with disease (CAD, hypertension, mitral valve disorders, pulmonary embolus, chronic lung disease, cor pulmonale, cardiomyopathy, hyperthyroidism, and the use of drugs such as digoxin, quinidine, and epinephrine) Symptoms result from high ventricular rate and loss of atrial "kick" → decreased CO → heart failure Increases risk of stroke
pacemaker
Used to pace the heart when the normal conduction pathway is damaged Pacing circuit consists of Programmable pulse generator (power source) One or more conducting (pacing) leads to myocardium
a fib
Usually on Coumadin results in a decrease in CO because of ineffective atrial contractions (loss of atrial kick) and/or a rapid ventricular response. Thrombi (clots) form in the atria because of blood stasis. An embolized clot may develop and pass to the brain, causing a stroke. Atrial fibrillation accounts for as many as 17% of all strokes. INCREASED RISK OF STROKES
asystole
Usually result of advanced cardiac disease, severe conduction disturbance, or end-stage HF Treat with immediate CPR and ACLS measures Epinephrine and/or vasopressin Intubation Poor prognosis
Precipitating causes must be identified and treated (e.g., hypoxia) VT with pulse (stable) treated with antidysrhythmics or cardioversion Pulseless VT treated with CPR and rapid defibrillation
VT tx
Sick Sinus Syndrome
arrhythmia in which bradycardia alternates with tachycardia
Monophasic defibrillator
deliver energy in one direction
excitability
is the ability to be electrically stimulated.
automaticity
is the ability to initiate an impulse spontaneously and continuously.
SA node
normal and primary pacemaker of heart (60-100 beats/minute)
Sinus Bradycardia
occurs in response to carotid sinus massage, Valsalva maneuver, hypothermia, increased intraocular pressure, vagal stimulation, and administration of certain drugs (e.g., β-adrenergic blockers, calcium channel blockers).
Ventricular Fibrillation
only cure is defibrillation
artifact
toothbrush tachy You will see _________ on the monitor when leads and electrodes are not secure, or if there is muscle activity (e.g., shivering) or electrical interference.
defibrillation
treatment of choice to end VF and pulseless VT.
AV Junctional Blocks
(damage to AV node area)
Sinus Bradycardia
<60 normal sinus rhythm When the SA node fires to slowly
Sinus Tachycardia
>100 (100-150) normal sinus rhythm When the SA node fires too fast...
3rd degree heart block
A complete heart block is when the signal from the SA node does not reach the AV node. A and V are not working together-no connection
asystole
ALWAYS check leads and in two leads! Ventricular standstill, no electrical activity, no cardiac output - no pulse! Cardiac arrest, may follow VF or PEA! Rate: absent due to absence of ventricular activity. Occasional P wave may be identified.
40-60 bpm
AV node
dysrhythmia
Abnormal heart rhythm
Step 3 P Waves
Are there P waves? Do the P waves all look alike? Do the P waves occur at a regular rate? Is there one P wave before each QRS?
Sinus node Atrial cells AV junction Ventricular cells
Arrhythmias are a result of issues in the:
Ventricular Fibrillation
Associated with MI, ischemia, disease states, procedures Unresponsive, pulseless, and apneic If not treated rapidly, death will result
First degree heart block
Associated with disease states and certain drugs Typically not serious Patients asymptomatic No treatment Monitor for changes in heart rhythm
Second-Degree AV Block, Type 2 (Mobitz II)
Associated with heart disease and drug toxicity Often progressive and results in decreased CO Treat with pacemaker
Ventricular Tachycardia
Associated with heart disease, electrolyte imbalances, drugs, CNS disorder Can be stable (patient has a pulse) or unstable (pulseless) Sustained VT causes severe decrease in CO Hypotension, pulmonary edema, decreased cerebral blood flow, cardiopulmonary arrest
Premature Ventricular Contractions
Associated with stimulants, electrolyte imbalances, hypoxia, heart disease Not harmful with normal heart but CO reduction, angina, and HF in diseased heart Assess apical-radial pulse deficit
atrial fibrillation
Atrial cells can also: fire continuously from multiple foci resulting in... No pwave Firing from different sites Stroke- blood pools and clots
Atrial Flutter
Atrial cells can fire continuously due to a looping re-entrant circuit resulting in "saw tooth"
Premature Atrial Contractions (PACs)
Atrial cells can: fire occasionally from a focus resulting in
PNS & SNS
Autonomic nervous system controls
Supraventricular Tachycardia (SVT)
Can have Paroxysmal SVT or SVT P waves get lost, hidden in QRS weak and dizzy low CO
Sinus Rhythms Premature Beats Supraventricular Arrhythmias Ventricular Arrhythmias AV Junctional Blocks
Categories of Arrythmias (5)
sinus tachy
Caused by vagal inhibition or sympathetic stimulation (hits you-umbrella story) Associated with physiologic and psychologic stressors (fever, exercise) Drugs can increase rate
Premature Atrial Contraction
Causes Stress Fatigue Caffeine Tobacco Alcohol Hypoxia Electrolyte imbalance Disease states
Synchronized Cardioversion
Choice of therapy for ventricular ( VT with a pulse) or supraventricular tachydysrhythmias Synchronized circuit delivers a countershock on the R wave of the QRS complex of the ECG
bradycardia
Common disease states associated with sinus ___________ are hypothyroidism, increased intracranial pressure, hypoglycemia, and inferior myocardial infarction (MI).
SA node, AV node, Bundle of His, Bundle Branches, Purkinje fibers
Conduction System of the Heart
PAC
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
PNS
Decreases rate of SA node Slows impulse conduction of AV node
PVC
Ectopic beats originate in the ventricles resulting in wide and bizarre QRS complexes. When there are more than 1 premature beats and look alike, they are called "uniform". When they look different, they are called "multiform" or "multifocal"
VT
Ectopic foci take over as pacemaker Monomorphic, polymorphic, sustained, and nonsustained (shapes) Considered life-threatening because of decreased CO and the possibility of deterioration to ventricular fibrillation
pulseless electrical activity
Electrical activity can be observed on the ECG, but no mechanical activity of the ventricles is evident, and the patient has no pulse Prognosis is poor unless underlying cause quickly identified and treated
Third-degree AV block
For symptomatic patients, a transcutaneous pacemaker is used until a temporary transvenous pacemaker can be inserted.
Heart
Four chambers Composed of three layers
vagal maneuvers
Gagging Holding your breath and bearing down (Valsalva maneuver). Immersing your face in ice-cold water (diving reflex). Coughing.
Electrocardiogram Monitoring
Graphic tracing of electrical impulses produced by heart Waveforms of ECG represent activity of charged ions across membranes of myocardial cells
Idioventricular Rhythm
HIS/Purkinje system takes over as the heart's pacemaker Treatment: pacing Rhythm: regular Rate: 20-40 bpm P wave: absent QRS: > .12 seconds (wide and bizarre)
1st Degree AV Block 2nd Degree AV Block, Type I 2nd Degree AV Block, Type II 3rd Degree AV Block
Heart Blocks aka AV Blocks
Endocardium Myocardium Epicardium
Heart: Composed of three layers
0.04 seconds
How much time does each small square on EKG paper represent? (ECG each small square =)
blocked, earlier, depolarize, premature, tachycardia
If conduction is depressed and if some areas of the heart are ______________ (e.g., by infarction), the unblocked areas are activated ________ than the blocked areas. When the block is unidirectional, this uneven conduction may allow the initial impulse to reenter areas that were previously not excitable but have recovered. The reentering impulse may be able to _________ the atria and ventricles, causing a ___________ beat. If the reentrant excitation continues, _______ occurs.
PACs
Look at p- it doesn't look the same Causes of PAC- old heart, not sleeping enough, too much coffee, too many cigs
Step 2- Regular or Irregular
Look at the R-R distances (using a caliper or monitor generated caliper). Regular? Are they equidistant ? Occasionally irregular? Consistently irregular? Interpretation?
defibrillation
Most effective when completed within 2 minutes of the onset of the dysrhythmia Passage of DC electrical shock through the heart to depolarize cells of myocardium Allows SA node to resume pacemaker role
defibrillation
No __________ with Asystole
0.12 - 0.20 seconds. (3 - 5 boxes)
Normal PR interval
Step 4 PR Interval
Normal PR interval: 0.12 - 0.20 seconds.
0.04 - 0.12 seconds (1 - 3 boxes)
Normal QRS duration
Sinus Bradycardia
Normal rhythm in trained athletes and during sleep Can occur in response to parasympathetic nerve stimulation and certain drugs Also associated with some disease states
Step 5 QRS Duration
Normal: 0.04 - 0.12 seconds (1 - 3 boxes)
Telemetry Monitoring
Observation of HR and rhythm at a distant site Two types Centralized monitoring system Monitor Watcher
Second Degree Type II
Occasional P waves are completely blocked (P wave not followed by QRS).
vfib
Only treatment is CPR and immediate defibrilation
defibrillation
Output is measured in joules or watts per second Recommended energy for initial shocks in defibrillation Biphasic: 120 to 200 joules Monophasic: 360 joules Immediate CPR after first shock
Palpitations Heart "skips a beat"
PAC Manifestations
Monitor for more serious dysrhythmias Withhold sources of stimulation β-adrenergic blockers
PAC tx
present pwave
PSVT difference from vtach
Vagal stimulation IV adenosine- stops heart for a couple seconds IV β-adrenergic blockers Calcium channel blockers Amiodarone Cardioversion
PSVT tx
pacemakers
Pace atrium and/or one or both of ventricles Most pace on demand, firing only when HR drops below preset rate Sensing device inhibits pacemaker when HR adequate Pacing device triggers when no QRS complexes within set time frame
150-220, 180, hypotension, dyspnea, angina
Paroxysmal Supraventricular Tachycardia (PSVT) Manifestations HR is _____-_____ beats/minute (add for clarification) HR > ______ leads to decreased cardiac output and stroke volume H__________ D_________ A___________
Atrial Fibrillation
Paroxysmal or persistent Most common dysrhythmia Prevalence increases with age Usually occurs in patients with underlying heart disease Can also occur with other disease states
PVC PAC
Premature Beats
Correct cause (Treatment relates to the cause of the PVCs ) Antidysrhythmics
Premature Ventricular Contractions tx
vfib
Prevent vtach --> will go into..
Electrical cardioversion
Process of applying an electrical shock to the heart with a defibrillator
automaticity excitability conductivity contractility
Properties of Cardiac Cells (Four properties of cardiac cells enable the conduction system to start an electrical impulse, send it through the cardiac tissue, and stimulate muscle contraction)
Hypovolemia Hypoxia Hydrogen ion (acidosis) Hyper-/hypokalemia Hypoglycemia Hypothermia Toxins Tamponade (cardiac) Thrombosis (MI and pulmonary) Tension pneumothorax Trauma
Pulseless Electrical Activity Hs and Ts Pneumonic
CPR followed by intubation and IV epinephrine Treatment is directed toward correction of the underlying cause
Pulseless Electrical Activity tx
Ventricular Tachycardia aka VTach
Pulseless Vtach or Vtach with Pulse? Not all ventricular tachycardias are pulseless and therefore, pulselessness must be established prior to beginning an algorithm. This is accomplished simply by checking a carotid or femoral pulse.
First degree heart block
Rate is Regular P waves are normal PR Interval =9 blocks or .36 (nl. 3-5 blocks) All PRs will be the same delay
Atrial Fibrillation (Afib)
Rate is regularly irregular No P-Waves since impulses are not originating from the SA node. (pwaves=SA node)
atrial flutter
Reentrant pathway in the right atrium with every 2nd, 3rd or 4th impulse generating a QRS (others are blocked in the AV node as the node repolarizes
asystole
Represents total absence of ventricular electrical activity No ventricular contraction Patient unresponsive, pulseless, apneic Must assess in more than one lead
vtach & vfib
Run of PVC- back to back- we worry about
60-100 beats/minute
SA node
Sinus Pause or Arrest
SA node fails to depolarize (forgets to tell the rest of the heart to beat!) no compensatory mechanisms take over. Sinus arrest is usually a transient pause in sinus node activity and can be caused by vasovagal. Involves cyclic changes in the heart rate during breathing. Common in children and often found in young adults.
sinus tachy
SA node is depolarizing faster than normal, impulse is conducted normally. Usually caused by stress, fever, exercise, etc.
Sinus Bradycardia
SA node is depolarizing slower than normal, impulse is conducted normally (i.e. normal PR and QRS interval). potential cause could be too much beta blocker
Normal Sinus Rhythm Sinus Bradycardia Sinus Tachycardia Sinus Arrest
Sinus Rhythms (4)
Calculate rate Determine regularity (R to R) Assess the P waves (p wave preceding QRS- atrial depolarization should look the same) Determine PR interval Determine QRS interval
Steps in ECG Interpretation
vagus
Stimulation of the _______ nerve causes a decreased rate of firing of the SA node and slowed impulse conduction of the AV node.
increases
Stimulation of the sympathetic nerves __________ SA node firing, AV node impulse conduction, and cardiac contractility.
Atrial Fibrillation (Afib) Atrial Flutter Paroxysmal Supra Ventricular Tachycardia (PSVT or SVT)
Supraventricular Rhythms
Third Degree aka Complete Heart Block
The P waves are completely blocked in the AV junction; QRS complexes originate independently from below the junction. Two separate rhythms atrial and ventricular
Third-degree AV block
The use of drugs such as atropine, dopamine (Intropin), and epinephrine is a temporary measure to increase HR and support blood pressure until temporary pacing is started. Patients will need a permanent pacemaker as soon as possible.
0.20 seconds
The width of 5 small boxes which equals one larger box represents how much time? One LARGE BOX
Third-degree AV block
Third-degree AV block usually results in reduced CO with subsequent ischemia, HF, and shock. Syncope from third-degree AV block may result from severe bradycardia or even periods of asystole.
VT
This results in hypotension, pulmonary edema, decreased cerebral blood flow, and cardiopulmonary arrest. The dysrhythmia must be treated quickly, even if it occurs only briefly and stops abruptly. Episodes may recur if prophylactic treatment is not started. Ventricular fibrillation may also develop.
Treat with immediate CPR and ACLS Defibrillation Drug therapy (epinephrine, vasopressin)
Ventricular Fibrillation tx
Pacemaker Spike
Ventricular capture (depolarization) secondary to signal (pacemaker spike) from pacemaker lead in the right ventricle.
Ventricular Tachycardia
Ventricular cells can: fire continuously due to a looping re-entrant circuit
Premature Ventricular Contractions (PVCs)
Ventricular cells can: fire occasionally from 1 or more foci-
Ventricular Fibrillation
Ventricular cells can: fire continuously from multiple foci-
vtach
Ventricular cells fire continuously due to a looping re-entrant circuit Rate usually regular, 100 - 250 bpm P wave: may be absent, inverted or retrograde QRS: complexes bizarre, > .12 Rhythm: usually regular
pacemaker cell
a cell generates spontaneous depolarizations that control the firing of all the cells in the network SA node
Drugs to control ventricular rate and/or convert to sinus rhythm (amiodarone and ibutilide most common) Electrical cardioversion Anticoagulation* Cardiac ablation
a fib tx
Supraventricular Tachycardia (SVT)
an abnormal heart rhythm arising from aberrant electrical activity in the heart; originates at or above the AV node
p wave
atrial depolarization
Pharmacologic agent Electrical cardioversion Ablation
atrial flutter tx
VT
can be stable (patient has a pulse) or unstable (patient is pulseless). Sustained ____ causes a severe decrease in CO because of decreased ventricular diastolic filling times and loss of atrial contraction.
Sinus Tachycardia
caused by dehydration, fever, exercise, anxiety, stress
Sinus Bradycardia
caused by fit person, deep sleep, drugs
conduction system of the heart
consists of specialized neuromuscular tissue located throughout the heart.
Start CPR while obtaining and setting up defibrillator Turn on and select energy Make sure sync button is turned off Apply gel pads Charge Position paddles firmly on chest Ensure "All clear"!!!!! Deliver charge
defibrillation
Biphasic defibrillators
deliver energy in two directions Use lower energies Fewer postshock ECG abnormalities
PAC
ectopic beats originate in the atria (but not in the SA node), therefore the contour of the P wave, the PR interval, and the timing are different than a normally generated pulse from the SA node.
Normal Sinus Rhythm
heart rhythm originating in the sinoatrial node with a rate in patients at rest of 60 to 100 beats per minute
ECG
is a graphic tracing of the electrical impulses produced in the heart. The waveforms on the ECG represent electrical activity produced by the movement of ions across the membranes of myocardial cells, representing depolarization and repolarization.
VT
is associated with MI, CAD, significant electrolyte imbalances, cardiomyopathy, mitral valve prolapse, long QT syndrome, drug toxicity, and central nervous system disorders. This dysrhythmia can be seen in patients who have no evidence of cardiac disease.
sinus tachy
is associated with physiologic and psychologic stressors such as exercise, fever, pain, hypotension, hypovolemia, anemia, hypoxia, hypoglycemia, myocardial ischemia, heart failure (HF), hyperthyroidism, anxiety, and fear. It can also be an effect of drugs such as epinephrine (EpiPen), norepinephrine (Levophed), atropine (AtroPen), caffeine, theophylline (Theo-Dur), or hydralazine (Apresoline). In addition, many over-the-counter cold remedies have active ingredients (e.g., pseudoephedrine [Sudafed]) that can cause tachycardia.
Third-degree AV block
is associated with severe heart disease, including CAD, MI, myocarditis, cardiomyopathy, and some systemic diseases, such as amyloidosis and progressive systemic sclerosis (scleroderma). Some drugs can also cause third-degree AV block, such as digoxin, β-adrenergic blockers, and calcium channel blockers.
Torsades de Pointes
is polymorphic VT associated with a prolonged Q-T interval of the underlying rhythm. Common causes for torsades de pointes include diarrhea, low blood magnesium, and low blood potassium. It is commonly seen in malnourished individuals and chronic alcoholics, since they are often deficient in potassium and/or magnesium. Also certain drug combinations.
contractility
is the ability to respond mechanically to an impulse
conductivity
is the ability to transmit an impulse along a membrane in an orderly manner.
asystole
is usually a result of advanced cardiac disease, a severe cardiac conduction system disturbance, or end-stage HF Generally the patient with asystole has end-stage heart disease or has a prolonged arrest and cannot be resuscitated. Treatment consists of CPR with initiation of ACLS measures. These include definitive drug therapy with epinephrine and/or vasopressin, and intubation.
v tach vfib 3rd degree (complete heart block asystole
lethal arrhythmias to know
sinus arrest
may arise from ischemic, inflammatory, or or fibrotic disease of the SA node, excessive vagal tone, sleep apnea, digitalis, and some antiarrhythmic and other drugs. (grow out of but watch)
Sick Sinus Syndrome
most often occurs in people older than 50. It is often due to scar-like damage to electrical pathways in the heart muscle tissue. CAD, HTN, Valvular Dz.
Hypotension Angina Dizziness or syncope Pale, cool skin Confusion or disorientation Weakness Shortness of breath
sinus brady manifestions
Stop offending drugs (dc or reduced) Atropine Pacemaker
sinus brady tx (3)
Dizziness Angina in patients with CAD Dyspnea Hypotension - due to decreased CO
sinus tachy manifestions (4)
Guided by cause (e.g., treat pain) β-adrenergic blockers (slow down) Vagal Maneuvers- eg.
sinus tachy tx
autonomic nervous system
system plays an important role in the rate of impulse formation, the speed of conduction, and the strength of cardiac contraction.
Supraventricular Tachycardia (SVT)
the AV junction can...fire continuously due to a looping re-entrant circuit -
AV junction
the portion of the electric conduction system of the heart located in the upper part of the interventricular septum that conducts the excitation impulse from the atria to the bundle of His.
QRS wave
ventricular depolarization
T wave
ventricular repolarization and relaxation
