Chapter 22 Management of Patients w/Arrhythmias & Conduction Problems Flashcards
1
Q
Arrhythmias
A
Disorders of the formation or conduction (or both) of the electrical impulse w/in the heart
2
Q
How are arrhythmias named?
A
They are named according to the site of origin of the electrical impulse & mechanism of formation or conduction involved
3
Q
Where do electrical impulses normally originate in the heart?
A
The sinoatrial (SA) node
-Near the vena cava in the RT atrium
4
Q
Function of the SA node
A
Serves as the pacemaker of the heart
-Electrical impulse stimulates and paces the cardiac muscle
5
Q
What is the normal SA node electrical impulse rate?
A
The normal rate is between 60-100 bpm
6
Q
Conduction
A
Process where the electrical impulse travels from the SA node to the atrioventricular (AV) node
7
Q
Function of the AV Node
A
Slow down the electrical impulse
-Allows the atria to contract & fill the ventricles w/blood
8
Q
Atrial Kick
A
When the atria contract & the ventricles fill w/blood
Accounts for ~1/3 of the volume ejected during ventricular contraction
9
Q
After the electrical impulse has traveled to the SA node, where does it go next?
A
It travels quickly to the Bundle of His on the RT, the RT & left bundle branches, & then the Purkinje fibers (located in ventricular muscle)
10
Q
Depolarization
A
The electrical stimulus
11
Q
Systole
A
Mechanical contraction of the heart
12
Q
Repolarization
A
Electrical relaxation of the heart
13
Q
Diastole
A
Mechanical relaxation of the heart
14
Q
SNS Influence on the Heart
A
Positive chronotropy
Positive dromotropy
Positive inotropy
Peripheral blood vessel constriction-> increased BP
15
Q
Positive Chronotropy
A
Increased HR
16
Q
Positive Dromotropy
A
Increased AV Conduction
17
Q
Positive Inotropy
A
Increased force of myocardial contraction
18
Q
PSNS Influence of the Heart
A
Negative chronotropy
Negative dromotropy
Negative Inotropy
Dilation of peripheral blood vessels-> Decreased BP
19
Q
Does SNS stimulation increase or decrease the incidence of arrhythmias?
A
It increases the incidence of arrhythmias
20
Q
Examples of SNS Stimulation
A
Exercise, anxiety, admin of catecholamines (dopamine)
21
Q
Examples of PSNS Stimulation
A
Beta-adrenergic meds, relaxation, anti-anxiety meds
22
Q
Electrocardiogram (ECG)
A
A record of a test that graphically measures the electrical activity of the heart, including each phase of the cardiac cycle
23
Q
Nursing Considerations for Obtaining an ECG
A
Gently abrading the skin with a clean dry gauze pad or sandpaper edge of the electrode
Wash area w/soap & H2O prior to adhesion
Clip excessive hair
24
Q
Artifact
A
Distorted, irrelevant, and extraneous ECG waveforms
(Can be caused by poor electrode adhesion)
25
What are electrodes and cables used for?
They are used to detect electrical activity of the heart
26
Hardwire Monitoring
A cardiac monitor at the patient's bedside for continuous reading
27
12-Lead ECG
An ECG machine placed at the patient's side for an immediate recording
28
What are leads?
Imaginary lines formed between two electrodes
- Provide a "snapshot" of electrical activity in the heart
29
Where is the white lead placed?
"White on right"
Placed on RT shoulder
30
Where is the black lead placed?
Placed on LT shoulder
31
Where is the green lead placed?
"White clouds over green pastures"
Placed on RT leg
32
Where is the red lead placed?
"Smoke over fires"
Placed on LT leg
33
Where is the brown lead placed?
"Chocolate is close to a nurse's heart"
Placed over Precordium
34
How often do we need to change lead locations?
Change it every 24 hrs (gel conductivity can decrease)
35
Telemetry
A small box that the patient carries and that continuously transmits the ECG information by radiowaves to a central monitor located elsewhere
36
Intermittent Monitoring
A very small device inserted under the skin or worn externally on a wrist band can perform ECG monitoring on demand whenever a patient is symptomatic
37
Continuous ECG Monitoring
A small, lightweight tape recorder-like machine that the patient wears for a prescribed period of time and that continuously records the ECG, which is later viewed and analyzed with a scanner
(Can include Holter monitor)
38
Positive Deflection
When an ECG waveform move towards the top of the paper
39
Negative Deflection
When an ECG waveform moves towards the bottom of the paper
40
P Wave
Represents the electrical impulse starting in the SA node and spreading through the atria
-Atrial depolarization
41
P-Wave Duration
0.11 secs or less normally (2.5 mm or less in height)
42
QRS Complex
Represents ventricular depolarization
43
QRS complex duration
Not all QRS complexes have the three waveforms
-Q wave: Normally less than 0.04 secs & less than 25% of the R-wave amplitude
QRS Duration: Normally less than 0.12 secs in duration
44
T Wave
Ventricular Repolarization (AKA resting phase)
Follows the QRS complex & usually follows the same direction
45
U Wave
Represents repolarization of the Purkinje fibers
-Sometimes appears in patients w/hypokalemia, HTN, or heart disease
-Follows the T-wave
-Usually smaller than the P-wave
46
PR Interval
AV Node Conduction
-Represents the time needed for sinus node stimulation, atrial depolarization, & conduction via AV node before ventricular depolarization
47
How do you measure the PR interval?
Measure from the beginning of the P-wave to the beginning of the QRS complex
-The spot where the isolectric line begins to change direction
48
Normal PR Interval Duration
Ranges from 0.12-0.20 secs in duration
49
ST Segment
Represents early ventricular repolarization
50
How do you measure the ST segment?
Lasts from the end of the QRS complex to the beginning of the T-wave
51
QT Interval
Represents the total time for ventricular depolarization & repolarization
52
How do you measure the QT interval?
Measure from the beginning of the QRS complex to the end of the T-wave
53
Normal QT Interval Duration
Ranges between 0.32-0.40 secs in duration, if HR is between 65-95 bpm
54
Deadly Consequence of QT Interval Prolongation
Torsades de Pointes
55
How do you measure the TP interval?
Measure from the end of the T-wave to the beginning of the next P-wave
56
PP Interval
Used to determine atrial rate & rhythm
57
How do you measure the PP interval?
Measure from the beginning of one p-wave to the next p-wave
58
RR Interval
Used to determine ventricular rate & rhythm
59
How do you measure the RR interval?
Measure from one QRS complex to the next QRS complex
60
ECG Time Measurements
Time measurements are recorded in hundredths, with a trailing zero if necessary
- 1 small box = 0.04 second
- 5 small boxes = 1 large box = 0.20 second
- 5 large boxes = 1 second
- 30 large boxes = 6 seconds
61
Steps of Rhythm Strip Interpretation
1) ) Rhythm: (Regular/Irreg)
2) HR: Fast or slow?
3) Locate the P wave: Is there a P wave for every QRS?
4) Determine the PR interval (Norm: 0.12-0.20 secs)
5) Identify the QRS (Normal <0.12 secs)
6) Identify the ST segment: Is it at baseline?
7) Identify the T wave: Upright? Peaked or flattened?
62
Step 1: Is the Rhythm Regular or Irregular?
Plot out the R-R intervals
Plot out the P-P intervals
For irreg determine if (essentially reg w/some irregularity or irregularly irregular)
- If the beat is the same, then it is regular
63
Step 2: Measure the HR
Count the number of R waves in a 6 second strip and multiply by 10
Is it fast or slow?
Normal is 60-100
Example:
7 R waves in a 6 second strip, the heart rate is 70
(7x10=70)
64
Step 3a Locate the P Wave: Is there a P wave for every QRS?
Normal: Similar in size, shape, appearance - may be assumed to originate from SA node
Different shapes: Diff foci (different places of origin)
65
Measuring HR: 300 Method
Count the # of big boxes between each R waves
Divide 300 by that number.
66
Measuring HR: 1500 Method
Count the # of small boxes between each P wave OR QRS complex
Divide 1500 by that number
66
Sequence Method
Find a P or R that peaks on the heavy red line
Assign the following numbers to the next heavy red line: 300, 150, 100, 75, 60 , & 50
Rate will be where the next P or R falls
67
Step 3b: Examine the P to QRS ratio
Every P-wave should be followed by a QRS complex
Every QRS complex should be preceded by a P-wave
68
Step 4: Determine PR Interval
Normal 0.12-0.20 seconds
Longer: 1st degree AV blocks, PR >0.20 (this will not be tested on)
Varied: 2nd and 3rd degree AV blocks (this will not be tested on)
69
Step 5: Examine the QRS complex
Size & shape should be similar
Width should be <0.12 secs
-Wider: Likely ventricular in origin
-Narrower: SA or AV node in origin
QT interval measurement should also be examined: Is it getting longer?
- 1/2 of the patient's R-R interval (usually 0.32-0.40 in a SR)
70
Steps 6 & 7: Examine ST segment & T waves
Look for ST elevation
71
Step 8: Interpret the Rhythm
Look for signs of hemodynamic compromise:
-Cool, clammy, diaphoretic, dizzy
-Decreased LOC
-Decreased BP
Remember: Check the patient first!
Always, always, always treat the patient, not the monitor!
72
Sinus rhythms originate in the...
...SA node
73
(Normal) Sinus Rhythm
Rate: 60-100 bpm (atrial & ventricular)
Rhythm: regular
P waves: uniform and upright
P to QRS Ratio: one for each QRS
PR Interval: 0.12-0.20 secs
QRS Complex: < 0.12 secs
74
Sinus Bradycardia
Rate: < 60 bpm (ventricular & atrial)
Rhythm: regular
P-waves: uniform and upright
P to QRS Ratio: one for each QRS
PR Interval: 0.12-0.20 secs
QRS Complex: < 0.12 secs
75
Sinus Tachycardia
Rate: 100 bpm (ventricular & atrial) (usually less than 120)
Rhythm: regular
P-waves: uniform and upright
P to QRS Ratio: one for each QRS
PR Interval: 0.12-0.20 secs
QRS Complex: < 0.12 secs
76
What occurs in atrial rhythms?
Atria takes over as the pacemaker (P waves all look different)
77
Signs & Symptoms of Sinus Tachycardia
Dizziness
Palpitations
SOB
Nausea
Lightheadedness
Chest pain
Syncope
78
Management of Sinus Tach
Correct causes:
- Give fluids, blood products, pain medications, reduce anxiety, remove meds/stimulants
If patient is hemodynamically unstable:
Vagal maneuvers:
- Carotid massage
- Gagging
Valsalva maneuver
- Coughing
- Face in ice water
- Straw/bubbles
Adenocard (Adenosine)
FAST IVP!!
Dose: 6mg, 12mg, 12mg
- MAX DOSE: 30 mg
Synchronized cardioversion
79
Defibrillation vs. Cardioversion
80
Prepping for Cardioversion: Oh, Say It Isn't So
Signed Consent BEFORE!!
O2 Monitoring
Suction
IV Access
Intubation supplies
Sedation & analgesics
- Propofol
81
Premature Atrial Contraction (PAC)
An electrical impulse begins in the atria, but not in the SA node (it's an ectopic beat)
-Impulse is faster than SA node-> causes early beat that leads to early contraction
82
PACs Causes
Atrial dilation
Substances: Caffeine, nicotine, alcohol
Ischemia/infarction
Anxiety
Electrolytes: Low K
Hypermetabloic States (Pregnancy)
83
Nursing Considerations for PAC
PACs are common in healthy individuals, and usually don't require treatment
However, frequent and/or symptomatic PACs may indicate a worsening condition, and could lead to more serious dysrhythmias
84
Signs & Symptoms of PACs
The patient may say, “My heart skipped a beat.”
A pulse deficit (a difference between the apical and radial pulse rate) may exist
85
Atrial Fibrillation (A-Fib) Characteristics
Rate: Atrial 350-600 bpm; ventricular- variable
Rhythm: irregularly irregular
P waves: no P-waves; fibrillatory waves
P to QRS Ratio: no identifiable P-waves
PR Interval: unable to measure
QRS Complex: usually narrow
86
Dangers of A-Fib
Loss of atrial kick decreases CO (20-30%)
Increased risk of emboli due to pooled, clotted blood in the atria
Risk for stroke & PE
87
Atrial Flutter (A-Flutter) Characteristics
Rate: Atrial 250-350; ventricular- variable
Rhythm: usually regular
P waves: sawtooth pattern
P to QRS Ratio: typically 3:1 or 4:1
PR Interval: unable to determine
QRS Complex: usually narrow
88
Signs & Symptoms of A-Fib
May be asymptomatic
May experience palpitations and clinical manifestations of heart failure
shortness of breath
Hypotension
dyspnea on exertion
fatigue
89
Treatment of A-Fib
Anticoagulation
Rate Control
Calcium channel blockers: Diltiazem, etc.
Beta blockers: Metoprolol, etc.
Conversion-
ANTICOAGULATE/TEE
Medications
Amiodarone, flecainide
Electrical
Surgical Procedures
LAAO- (WATCHMAN) Reduces the risk of LAA blood clots from entering the bloodstream- stroke
Maze procedure- small transmural incisions are made in the atria resulting in scar formation
Ablation therapy
90
A-fib/flutter Causes
Impairment to cardiac system
-HTN
-CHF
-Valve disease
-Atrial dilation
-Hypertrophy
-Surgery
Age
Diabetes
Obesity
OSA
Alcohol abuse
Smoking
Genetics
91
Nursing Considerations for A-fib/flutter
Examine causes
-Sustained vs non-sustained
-Cardiac conds vs lifestyle modification
Procedures:
-Cardioversion/TEE (ECHO): Check for blood clots (if clots are present, not a candidate)
-Fast-> A fib ablation
-Slow-> nodal ablation & pacemaker
92
Signs & Symptoms of Aflutter
Tend to be more symptomatic than A-fib
Chest pain
SOB
Low BP
93
Med Management of A-fib/flutter
Rate management for goal HR <80 bpm
-Class II antiarrhythmic beta-blockers and Class IV antiarrhythmic calcium channel blockers (like metoprolol and diltiazem)
Rhythm management
-Class III and IC antiarrhythmics (like Amiodarone, Dofetilide, Sotolol, Flecainide)
Clot prevention
-Anticoagulants and Antiplatelets (like Pradaxa, Eliquis, Aspirin, Warfarin)
->Warfarin is based on INR goal of 2-3 and needs lots of education*Based on risk score
94
What occurs in ventricular rhythms?
Ventricles become the pacemaker
95
Premature Junctional Complex
Rate: depends on underlying rhythm
Rhythm: irregular due to early P waves, creating a PP interval that is shorter than others. Sometimes followed by a longer-than-normal PP interval, but one that is less that twice the normal PP interval (noncompensatory pause)
P waves: May be absent, may follow the QRS, or may occur before the QRS
P to QRS Ratio: 1:1
PR Interval: less than 0.12
QRS Complex: usually normal, but may be abnormal or absent (blocked)
96
PJC Causes
Digitalis Toxicity
HF
CAD
97
Junctional Rhythm
Rate: Ventricular 40-60 bpm, Atrial 40-60 bpm is P waves are discernible
Rhythm: regular
P waves: May be absent, after the QRS, or before the QRS, may be inverted
P to QRS Ratio: 1:1 or 0:1
PR Interval: If the P is in front of the QRS, the PR is less than 0.12 seconds
QRS Complex: Usually normal, may be abnormal
98
Junctional Rhythm Causes
99
Signs & Symptoms of Junctional rhythm
Symptoms of reduced cardiac output
Lightheadndness
Palpitations
Activity intolerance
Chest heaviness
Neck tightness or pounding
Shortness of breath
Weakness
100
Junctional Rhythm Management
Treatment: if symptomatic-same as for sinus bradycardia
Atropine
Emergency pacing
101
Junctional Tachycardia
Rate: Ventricular 70-120 bpm, Atrial 70-120 bpm is
P waves are discernible
Rhythm: regular
P waves: May be absent, after the QRS, or before the QRS, may be inverted
P to QRS Ratio: 1:1 or 0:1
PR Interval: If the P is in front of the QRS, the PR is less than 0.12 seconds
QRS Complex: Usually normal, may be abnormal
102
Junctional Tachy Causes
103
Signs & Symptoms of Junctional Tachy
Will depend on precipitating cause
Symptoms of digoxin toxicity may be present
104
Management of Junctional Tachy
Eliminate or treat the underling cause
105
Atrioventricular Nodal Reentry Tachycardia (AVNRT)
AKA Paroxysmal Atrial Tachycardia (PAT) , Paroxysmal supraventricular tachycardia (PSVT)
Rate: Atrial 150-250 bpm, ventricular 120-200 bpm
Rhythm: Regular, sudden onset and termination
P waves: Difficult to discern
P to QRS Ratio: 1:1, 2:1
PR Interval: If the P is in front of the QRS, the PR is less than 0.12 seconds
QRS Complex: Usually normal, may be abnormal
106
PAT Causes
Caffeine
Nicotine
Hypoxemia
Stress
Not associated w/ underlying structural heart disease
107
Signs & Symptoms of PAT
Decreased cardiac output can cause
- Restlessness
- Chest pain
- SOB
- Pallor
- Hypotension
- Loss of consciousness
108
Management of PAT
Stable
- Vagal maneuvers
- Adenosine: 6mg/12mg/12mg IV, rapid push
- IV calcium channel blocker, IV beta-blocker, or IV digoxin
-Consider synchronized cardioversion
Unstable: Immediate synchronized cardioversion
Long-Term
Ablation Therapy
109
Premature Ventricular Contraction (PVC)
"Wide & Bizzare"
Rhythm: Irregular
P waves: Depends on timing of the PVC, may or may not be visible
P to QRS Ratio: 0:1, 1:1
PR Interval: If P is in front of QRS, PR interval is less that 0.12
QRS wide ( > or = 0.12 sec) and bizarre
T-wave usually opposite QRS direction
Interrupts regularity of underlying rhythm
110
PVCs Causes
Substances: Caffeine, nicotine, alcohol
Ischemia/infarction
Digitalis Toxicity
Increased workload to the heart (HF)
Electrolytes: Low K & Mg, Acidosis
111
Are PVCs more urgent when it is unifocal or multifocal?
Multifocal are more urgent
112
Treatment
Usually doesn't need treatment, solely monitoring
Correct the underlying cause
113
Ventricular Tachycardia (V-Tach)
Usually regular - may be slightly irregular
Typically 150-250 bpm may be faster or slower
No P-waves
QRS wide & bizarre (a lot of PVCs that do not stop)
114
V-Tach Causes
Same as PVCs, but worsened conditions
Large areas of ischemia w/ MI
Very low EF
Critically low K/Mg
115
Ventricular Fibrillation (V-fib)
CALL FOR HELP IMMEDIATELY!!!!!
D-FIB!!
- If you cannot defib, immediately start CPR
Severe electrical chaos in the ventricles
Multiple foci fire in erratic and disorganized manner
No ventricular contraction
No perfusion to vital organs
116
Signs & Symptoms of Vtach
May or may not have a pulse
- Check carotid or femoral pulse
- If in a code, check femoral
Hypotension
117
Treatment
Treatment:
Underlying cause must be identified and corrected
Long term management may include placement of an ICD
IF STABLE:
12 lead EKG
Adenosine 6 mg rapid IV push, if regular and monomorphic
Antiarrhythmic bolus followed by maintenance infusion
Amiodarone 150 mg over 10 minutes, then 1 mcg/min. for 1st 6 hours followed by 0.5 mcg/min for 18 hours, then oral Amiodarone
Lidocaine most common alternative antiarrhythmic
Procainamide 20 to 50 mg/min until suppressed followed by maintenance of
-1 mg/min for 1st 6 hours
Sotalol (Betapace) 100 mg over 5 minutes (avoid with prolonged QT interval)
IF UNSTABLE:
Immediate synchronized cardioversion if available for monomorphic VT
If not available, use treatments below until cardioverter arrives.
118
Polymorphic V-Tach or Torsades de Pointes
Usually associated with prolonged QT interval
Many antiarrhythmics ineffective.
Common Treatments:
Magnesium Sulfate, IV – first line therapy
Isoproterenol
Mexiletine
Atrial pacing (shortens QT interval)
Antiarrhythmics can be considered but often ineffective and sometimes harmful
119
Complications of V-fib
If untreated, can lead to death
120
V-Fib Causes
Cardiac damage
-Ischemia/CAD/MI
-Cardiomyopathy
-Valve disease
-Untreated V Tach
ELECTRIC SHOCK
Acid-base and electrolyte imbalances
Medication side effects/toxicity
121
Treatments for
V-fib
No pulse/No respirations→→Call for help
Early and immediate defibrillation
Do not delay defibrillation!
High quality CPR
Medical management
- Epinephrine, 1 mg IV push q 3-5 minutes
- Amiodarone, 300 mg initial bolus, followed by 150 mg
- Lidocaine is appropriate substitute for amiodarone
Post-resuscitation Management: Amiodarone or Lidocaine drip
Identify reversible/underlying causes
122
Super Ventricular Tachycardia (SVT)
Any HR > 150
Synchronized cardioversion (symptomatic/ unstable cases)
Adenosine per ACLS guidelines
123
Asystole (Ventricular Standstill)
"Flatline"
No electrical activity
124
Asystole (T/F) You can defibrillate this rhythm
False, there is no rhythm to regulate (can only treat via medication/CPR until a rhythm is regained)
125
Asystole Causes
Attempted Defib of Vtach or VFib
Decompensation of prolonged VFib
Hs & Ts
126
H's & T's of Asysteole
H's
- Hypovolemia
- Hypoxia
- H+ (acidosis)
- Hypo/Hyperkalemia
- Hypothermia
T's
-Tension pneumothorax
- Tamponade, Cardiac
- Toxins
- Thrombosis (coronary)
- Thrombosis (pulmonary
127
Treatment for Asystole
Immediate action: activate emergency system protocols
High quality CPR
Medical management
- Epinephrine, 1 mg IV push q 3-5 minutes
- Amiodarone, 300 mg initial bolus, followed by 150 mg
Underlying cause must be corrected- think H’s and T’s.
Very poor prognosis
Prevention is critical!
128
Pulseless Electrical Activity (PEA)
Rate: varies
Rhythm: varies
P waves: varies
P to QRS Ratio: varies
PR Interval: varies
QRS Complex: varies
129
Which cardiac rhythms can be defibrillated?
V-tach & V-fib
130
Causes of Bradycardia
Lower metabolic needs (sleeping, athletic heart)
Vagal stim (vomiting, straining)
Med side-effects (beta blockers, ca+blockers)
Nodal dysfunc/sick sinus syndrome
Coronary artery disease, HF, MI
131
Long QT Syndrome
Delay in repolarization of the heart after the initial depolarization and ventricular contraction.
QRS to T = 0.36-0.44, greater than 0.5 is cause for immediate concern
132
Causes of Long QT Syndrome
Hereditary
Common cause of cardiac arrest in young people
Genetic testing available
Certain medications
- Zofran
133
Bundle Branch Blocks
First division of the ventricle conduction after the bundle of His.
A delay or blockage of electrical impulses, resulting in the heart pumping blood less efficiently.
Cause differs based on which bundle branch is affected
LBBB – MI, HTN, myocarditis, cardiomyopathy
RBBB – PE, MI, congenital heart defects, pulmonary HTN, myocarditis
Signs/symptoms:
Usually asymptomatic
Dizziness, syncope
Treatment is usually not needed if asymptomatic
134
1st Degree AV Block
Prolonged PR interval
greater than 0.20 seconds
Constant PR interval for each beat
Usually asymptomatic and only needs monitoring
If symptomatic, treat with atropine
135
2nd Degree AV Block: Mobitz Type I (Wenckebach)
Steady lengthening of the PR interval
QRS complex is dropped or blocked
PP interval regular
RR interval irregular
QRS normal
Self-limiting; rarely progresses
May decrease cardiac output
Usually asymptomatic and only needs monitoring
If symptomatic, treat with atropine
136
2nd Degree AV Block: Mobitz Type II
PR interval is fixed
PP interval is regular
Occasional P wave not followed by QRS
Typically unstable and needs treatment
Treatment:
Atropine
if ineffective then pacemaker
137
3rd Degree AV Block: Complete
THE WORST AV BLOCK!!
Atria and ventricles beat independently of each other
P waves not associated with QRS complex
Causes:
Extensive MI, acidosis, hypoxia, hyperkalemia, dig tox., post-cardiac surgery
Treatment:
Eliminate cause
Atropine can be given but ineffective
Transcutaneous, transvenous, or implanted permanent pacemaker
138
Pacemaker Terms
Rate
Pacing rate-in bpm
Usually a ‘backup rate”
Mode
demand or fixed
Sensitivity: millivolts (mV)
Minimum myocardial voltage required to be detected
Lower number = more sensitive
Output: milliamperes (mA)
Current that produces a pulse
Capture
Pacing rate-in bpm
Usually a ‘backup rate”
Pacing or capture threshold
Minimum amount of current (mA) required to initiate depolarization of the paced chamber
Spike
Line that represents pacing on EKG
139
Failure to Pace
Fails to initiate an electrical stimulus when it should fire
The alarm clock isn't working
140
Failure to Capture
When the pacemaker generates an electrical impulse (pacer spike) and no depolarization is noted
The alarm clock is going off, but sleeping through it
141
Failure to Sense
When the pacemaker does NOT sense the patient's own cardiac rhythm & initiates an electrical impulse
You wake up before the alarm clock and after you began getting ready, the alarm goes off
142
Pacemaker Surveillance
143
Implantable Cardioverter-Defibrillator
144
Patient Education for Pacemaker
1st 2 weeks:
- Immobilize arm
- No heavy lifting
- No immersion in water (bath, swim)
- No driving
Forever: Check pulse
Report any shortness of breath or dizziness
Carry ID card
Keep pacemaker 6” away from:
- Cell phones
- E-cigarettes
- Headphones
Avoid medical procedures including:
- Electrocautery
- MRI
- Radiation therapy
- Microwave diathermy
- Lithotripsy
TENS
Avoid contact sports
Household appliances are okay!
Avoid metal detectors,
body scanners are okay!
145
Bradycardia Treatments
Meds like atropine (per MD order) & epinephrine (per ACLS guidelines)
Pacemaker (symptomatic/too slow)
146
PAC & PVC Treatment
Treat underlying causes
-Replace electrolytes
-Reduce stress/anxiety
-Dietary changes
Asymptomatic: No treatment
Symptomatic: Amino & beta blockers
147
Defibrillation
Electrical current delivered through the chest wall and heart to depolarize myocardial cells
148
What are the 2 types of defibrillation?
AED & Manual
149
Purpose of Defibrillation
Goal is to allow primary pacemaker to resume control
150
Defibrillator Steps
1) Self-adhesive pads are applied to the patient's chest
-Remove hair PRN
2) Protect the patient from burns
3) Defibrillator charged and "All clear"
4) Shock is delivered
5) Begin CPR
5a) If normal rhythm resumes: Assess pulse
5b) If no pulse...CPR resumes
151
Is defibrillation used for atrial dysrhythmias or ventricular dysrhythmias?
Defibrillation is used for ventricular dysrhythmias
-Cardioversion is used for atrial dysrhythmias
152
General Nursing Interventions for Dysrhythmias
Continue to monitor HR & CO
Position pt as safely as indicated
Perform & interpret physical assessment
Prepare & admin meds as ordered
Apply O2 as needed
Page primary provider to update & obtain new orders
Reduce pt anxiety
Monitor for side effects of meds
Educate pt about potential treatments & associated risks
153
Emergent Nursing Interventions for Dysrhythmias
Position pt safely for CPR
Begin CPR/call code if indicated
Apply O2 PRN
Call for help from charge nurse or MET/MRT/RRT
Page primary provider as quickly as possible
Call for stat EKG if needed
Prepare for IV infusions or pushes
Bring code cart and/or defibrillator to the doorway
