Patients w/ Conduction Probs Flashcards
How many seconds are the tiny boxes worth on a 6 second strip?
0.04 seconds
How much are the bigger boxes worth on a six second strip?
0.20 seconds
How many boxes are in a 6 seconds strip?
30
1R 2R 3P 4PR 5QRS
1 Rate 2 Rhythm is regular or irregular? 3 P-wave 4 PR interval 5 QRS complex < .12 seconds?
How do you find the rate for step 1 on a 6 second strip?
Count how many QRS complexes appear on a 6 second strip and multiply by 10
What do you determine in step 2 about the rhythm?
If it is regular or irregular-look at QRS complexes
What do you determine about the P-wave in step 3?
do they all look alike and do they come before and after the QRS complexes
What is a normal PR Interval?
0.12-0.20 seconds
How do you measure the PR intervals?
Measure from the beginning of the P-wave to the beginning of the QRS complex
-count how many tiny boxes are between and multiply by 0.04 seconds
How do you measure the QRS duration in step 5?
measure from beginning of QRS complex to the end and multiply be 0.04 seconds
What does the P-wave represent?
the electrical impulse starting in the SA node and spreading throughout the atria
-atrial depolarization
What does the PR interval represent?
the time needed for SA node stimulation, atrial node depolarization, and conduction through AV node before ventricular depolarization
What does the QRS complex represent?
ventricular depolarization
How long is a normal QRS duration?
less than .12 seconds
What does the T-wave represent?
ventricular repolarization or electrical recovery
When does NORMAL Sinus Rhythm occur?
when the electrical impulse starts at the SA node and travels through the normal conduction pathway
Normal Sinus Rhythm serves as a what?
Baseline
Normal Sinus Rhythm Characteristics
Rate: 60-100 Rhythm: regular P-wave: normal and consistent PR Interval: b/t .12-.20 QRS duration: less than .12 seconds
What is the ONLY difference b/t Normal Sinus Rhythm and Sinus Arrhythmia?
Irregular Rhythm
A Sinus Arrhythmia’s irregular rhythm may correlate w/ what?
Breathing
Rate increases w/ inspiration and decreases w/ expiration
When does Sinus Bradycardia occur?
when the SA node creates an impulse at a slower rate than normal
What is the ONLY difference b/w Sinus Brady and Normal Sinus Rhythm?
rate is less than 60 bpm
What are some causes of Sinus Brady?
- sleep
- pain
- athleticism
- vomiting/hypovolemia
- suctioning
- medications
- increased intracranial pressure
- MI
- anemia
What medications may cause Sinus Brady?
- calcium channel blockers
- amiodarone
- beta blockers
- digoxin
Sinus Brady ECG Characteristics
Rate: < 60 bpm Rhythm: regular P-wave: present before and after QRS and looks same PR: normal QRS: normal
Treatment for symptomatic Sinus Brady may be what?
- transcutaneous pacing
- atropine
- dopamine
- epinephrine
When does Sinus Tachycardia occur?
When SA node creates an impulse at a faster rate than normal
What are some causes of Sinus Tachy?
- stress
- medications
- stimulants
- drugs
- emotions/agitation
- blood loss/hemorrhage/hypovolemia
- sepsis
- hyperthyroidism
- anemia
- infection/inflammation
ECG Characteristics of Sinus Tachycardia
Rate: > 100 bpm Rhythm: regular P-wave: before and after QRS and same PR: normal QRS: normal
What is a Premature Atrial Complex (PAC)?
single ECG complex that occurs when electrical impulse starts in the atrium before the next normal impulse from the SA node
What may cause a PAC?
- caffeine
- alcohol
- nicotine
- hypervolemia
- anxiety
- hypokalemia
- injury/infarction
ECG Characteristics w/ PAC
Rate: depends on underlying rhythm Rhythm: irregular P-wave: all same except one PR interval: all normal except one QRS duration: normal
How many PAC’s occurring in one strip is considered to be a sign of worsening arrhythmia?
more than 6 per min
Where does Atrial Flutter occur?
in the Atrium
What is the ATRIAL rate for atrial flutter?
220-350 bpm
What happens w/ Atrial Flutter?
The atrial rate is faster than what the AV node can conduct so not all atrial impulses are conducted to the ventricle
Causes of Atrial Flutter
- CAD
- hypertension
- mitral/tricuspid valve disease
- hyperthyroidism
- chronic lung disease
- pulmonary emboli
- cardiomyopathy
S/S of Atrial Flutter IF present
- fatigue
- light headed
- chest pain
- SOB
- low BP
- blood clots
ECG Characteristics for Atrial FLUTTER
Rate: Atrial 220-350 bpm; Ventricular 75-150 bpm
Rhythm: usually regular
P-wave: flutter waves-“saw tooth pattern”
PR: not measurable
QRS: normal
What is the initial treatment for Atrial Flutter?
Cardioversion or radiofrequency ablation
Atrial Fibrillation causes what?
Rapid, disorganized , and uncoordinated electrical activity w/in the atria
A-fib can appear as what?
- transient, starting and stopping suddenly
- occur for short period of time
- may be persistent
Long-standing Persistent A-fib
continuous AF or lasting longer than 12 months
When is the term “Permanent A-fib” used?
when the physician and patient together decide to stop further attempts of NSR
Nonvalvular A-fib
AF exists in the absence of preexisting heart valve problems
Patients in A-fib are at an increased risk for what?
- blood clots/DVT
- Pulmonary embolism
- MI
- stroke
- kidney infarction
- myocardial ischemia
- heart failure
S/S of A-fib
- asymptomatic
- decreased CO
- fatigue
- malaise
ECG Characteristics of A-fib
Rate: Atrial Rate 300-400, w/ variable ventricle response Rhythm: irregular P wave: no discernible p-wave PR: not measurable QRS: normal
Treatment for A-fib depends on what?
- cause
- duration
- symptoms
- age
- comorbidities
Treatment for A-fib
-cardioversion by meds or electrical shock
Cardioversion via Medications
Intravenous ibutilide
procainamide
amiodarone
When will pharmacological cardioversions be more effective?
When A-fib is more recent
When are electrical cardioversions indicated?
when a patient w/ new onset AF is hemodynamically unstable
What will be performed before a cardioversion for a patient w/ new-onset AF for over 48 hours or when the onset is unknown?
trans-esophageal echocardiography (TEE)
Why is a TEE performed before a cardioversion?
to rule out left atrial thrombus because when a patient converts back to NSR the risk for PE is increased
How long does a patient need to be on anticoagulants after a cardioversion?
4 weeks to prevent thromboembolism
For patients who are unresponsive to medications w/ A-fib what is considered?
Pacemaker implantation or catheter ablation
Supra-ventricular Tachycardia is a broad term for what?
to describe tachycardias where the atrial or ventricular rate exceeds 100 bpm at rest
SVT electrical impulses are usually stimulated from where?
HIS bundle or AV node
SVT is the term that covers what?
- Sinus tachy
- Focal/multifocal atrial tachy
- junctional tachy
Symptoms of SVT vary depending on what?
- frequency/duration of episodes
- timing of SVT
- rhythm
S/S of SVT
- palpitations
- chest pain
- SOB
- dizziness
- syncope
- panic/anxiety
ECG Characteristics for SVT
Rate: > 100 bpm Rhythm: regular P wave: if visible sometimes inverted seen after QRS PR: not measurable QRS: in paroxysmal SVT its normal
Treatment for Atrial SVT depends on what?
- cause
- duration
- symptoms
- age
- comorbidities
What is recommended as the first step for Atrial SVT’s to discontinue rhythm in patients who are hemodynamically stable?
Vagal maneuvers
What medication is given short term for patients w/ Stable SVT’s?
Adenosine
If SVT becomes unstable what is the recommended treatment?
synchronized cardioversion
For ongoing management of SVT’s patients mat be placed on what?
- beta blockers
- diltiazem
- verapamil
When does a Junctional Rhythm occur?
when the AV node instead of the SA node becomes the pacemaker of the heart
Why would the AV node take over?
- SA node slows from increased vagal tone
- impulse cannot be conducted through AV node b/c of heart block
Junctional Escape Rhythm may be caused by what?
- acute coronary syndromes
- valvular disease
- hypoxia
- increased parasympathetic tone
- medications
What medications may cause junctional escape rhythms?
- digoxin
- beta blockers
- calcium channel blocker
ECG Characteristics for Junctional Escape Rhythms
Rate: 40-60 bpm
Rhythm: regular
P wave: if visible may be before, during, or after
QRS: normal
What is the treatment for Junctional escape rhythms if symptomatic?
Same as for bradycardia
- temporary/permanent pace maker
- IV atropine
- IV epinephrine
If there is a delay or defect in the conduction system w/in the ventricles what happens to the QRS complex?
It will be prolonged or widened
> .12 seconds
What may cause Ventricular Arrhythmias?
- ventricular hypertrophy
- cardiomyopathy
- myocardial ischemia/infarction
When would Ventricular Arrhythmias require temporary pacing?
When there is an acute MI that progresses to complete heart block
What is a premature ventricular complex (PVC)?
Impulse that starts in the ventricle and is conducted through the ventricles before the next normal sinus impulse
PVC’s may occur in normal healthy people because of what?
Intake of caffeine, nicotine, or alcohol
Causes of PVC’s
- cardiac ischemia/infarction
- exercise
- fever
- hypervolemia
- heart failure
- tachycardia
- hypoxia
- acidosis
- hypokalemia
PVC’s may be an early marker for what?
Heart failure
Patients w/ PVC’s may be asymptomatic or complain of what?
their heart “skips a beat”
Bigeminy PVC
a rhythm in which every other complex is a PVC
Three or more successive PVC’s are termed as what?
Ventricular Tachycardia
ECG Characteristics for PVC
Rate: depends on underlying rhythm Rhythm: regular P wave: depends on timing of PVC PR: if in front of QRS its <0.12 sec QRS: wider/abnormal in PVC
What is Ventricular Tachycardia defined as?
three or more consecutive ventricular beats occurring at a rate more than 100 bpm
Ventricular Tachycardia may occur with what?
- ACS
- after MI
- inherited arrhythmia syndromes
- electrolyte imbalances
- cardiomyopathies
- structural heart disease
Ventricular tachycardia can deteriorate into what?
Ventricular fibrillation
S/S Ventricular Tachycardia
- hypotension
- syncope
- pulselessness
- unresponsiveness
ECG Characteristics for Ventricular Tachy
Rate: 100-250 bpm Rhythm: regular P wave: not visible PR interval: none QRS: > 0.12 sec
Monomorphic Ventricular Tachy
consistent QRS shape and rate
Polymorphic V-tach
varying QRS shapes and rhythms
If a patient is stable w/ V-tach the only treatment may be what?
Continued assessment w/ 12-lead ECG
What is often the medication of choice for a stable patient w/ V-tach?
Amiodarone
What is the treatment of choice for Monophasic V-tach in symptomatic patient?
Cardioversion
When would the nurse begin to prepare the patient w/ V-tach for a cardioversion?
When the patient begins to demonstrate hypotension, shock, angina, symptoms of CHF, edema, or symptoms of cerebral hypoperfusion
What is Ventricular Fibrillation?
Rapid, disorganized ventricular rhythm that causes ineffective quivering of the ventricles
S/S of V-fib
Absence of audible heart beat, palpable pulse, and respirations
What is imminent w/ V-fib?
Cardiac arrest and death
ECG Characteristics for V-fib
Rate: often cannot be determined but > 220 bpm Rhythm: irregular P wave: not visible PR: none QRS: none
What is the treatment of choice for V-fib?
- immediate defibrillation
- immediate CPR
- activation of emergency services
What vasoactive medications should be delivered after the second rhythm check for someone in V-fib?
Epinephrine
What does a Ventricular Escape Rhythm occur? (Idioventricular Rhythm)
When the impulse starts in the conduction system below the AV node
Who is creating the impulse in a Ventricular Escape Rhythm?
Purkinje Fibers
ECG Characteristics of Ventricular Escape Rhythm
Rate: 20-40 bpm Rhythm: regular P wave: not visible PR: none QRS: 0.12 secs or more
If the rate is greater than 40 bpm w/ Ventricular Escape Rhythms it is known as what?
Accelerated ventricular escape rhythm
Treatment for Ventricular Escape Rhythm
- same as asystole if patient is in cardiac arrest
- if not in cardiac arrest same as if bradycardia
- administer IV atropine and vasopressors
- emergency pacing
What is Ventricular Asystole characterized as?
“flat line”
Absent of QRS complexes confirmed in two different leads
How is Asystole treated?
Focusing on CPR and identifying underlying cause
Possible causes of Asystole
- hypoxia
- acidosis
- severe electrolyte imbalance
- overdose
- hypovolemia
- cardiac tamponade
- tension pneumothorax
- trauma
- hypothermia
When does SR w/ First Degree Heart Block occur?
When atrial conduction is DELAYED through the AV node, resulting in prolonged PR interval
Causes of First Degree Heart Block
- beta blockers
- calcium channel blockers
- digoxin
- vomiting
- Valsalva maneuver
ECG Characteristics of First Degree Heart Block
Rate: depends on underlying rhythm Rhythm: regular P wave: present before and after and consistent PR: greater than 0.20 secs QRS: normal
When is a patient w/ First Degree Heart Block treated?
When symptoms related to bradycardia are presentre
Second Degree Heart Block Type 1 is also known as what?
Wenckebach
What causes Second Degree Heart Block type 1?
a gradual and progressive conduction delay through the AV node
When does SDHB Type 1 occur?
When there is a repeating pattern in which all but 1 of a series of atrial impulses are conducted through the AV node
What is seen w/ the PR interval on an ECG of SDHB Type 1?
Increasing PR interval is seen w/ each successive beat until a P wave is seen w/o a resulting QRS
S/S of Wenckebach
- symptoms of bradycardia
- chest discomfort
- dyspnea
- hypotension
Causes of Wenckebach
- increased parasympathetic tone
- ischemia
- or meds that slow conduction
ECG Characteristics of Wenckebach
Rate: atrial faster than ventricular Rhythm: Atrial regular/ventricular irregular P wave: normal PR: increasingly longer QRS: normal
If patient w/ Wenckebach is symptomatic how is it treated?
Atropine or transcutaneous pacing
