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EKG Rhythms

EKG interpretation
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Sinus Rhythm
Rate: 60 - 100
Regularity: Regular
P wave: Upright in Lead II; one per QRS; uniform shape
PR interval: 0.12 - 0.20; constant
QRS interval: < 0.12
Cause: Normal
Adverse Effects: None
Treatment: None
Sinus Bradycardia
Rate: < 60
Regularity: Regular
P wave: Upright in Lead II; one per QRS; uniform shape
PR interval: 0.12 - 0.20; constant
QRS interval: < 0.12
Cause: MI, vagal stimulation, hypoxia
Adverse Effects: None necessarily; maybe decreased cardiac output
Treatment: Atropine if symptoms; consider 02
Sinus Tachycardia
Rate: 101 - 160
Regularity: Regular
P wave: Upright in Lead II; one per QRS; uniform shape
PR interval: 0.12 - 0.20; constant
QRS interval: < 0.12
Cause:SNS stimulation, MI, hypoxia, pulmonary embolus, CHF, thyroid storm, fever, vagal inhibition
Adverse Effects: Maybe none; maybe decreased cardiac output
Treatment:Treat the cause; consider O2 and beta blockers
Sinus Arrhythmia
Rate: Varies. Increased with inspiration, decreased with expiration
Regularity: Irregular; R-R varies by > or = 0.16 secs
P wave: Upright in Lead II; one per QRS; uniform shape
PR interval: 0.12 - 0.20; constant
QRS interval: < 0.12
Cause: The breathing pattern
Adverse Effects: Usually none
Treatment: Atropine if HR slow and symptoms
Sinus Arrest
Rate: Can occur at any rate
Regularity: Regular but interrupted
P wave: Normal before pause; may be different or absent after
PR interval: Normal before pause; may be different or absent after
QRS interval: < 0.12 unless ventricular escape beat present
Cause: Sinus node ischemia, hypoxia, digitalis toxicity, excessive vagal tone, medication side effects
Adverse Effects: Maybe none; maybe decreased cardiac output; lower pacemaker may take over after pause
Treatment: Consider O2; atropine or pacemaker if symptoms
Sinus Exit Block
Rate: Can occur at any rate
Regularity: Regular but interrupted
P wave: Normal before and after the pause; all shaped the same
PR interval: 0.12 - 20
QRS interval: < 0.12
Cause: Medication side effects, excessive vagal tone, hypoxia
Adverse Effects: Same as sinus arrest; pause is a multiple of R-R; sinus resumes after pause
Treatment: Consider O2; atropine or pacemaker if symptoms
Wandering Atrial Pacemaker (WAP)
Rate: Mean rate < 100
Regularity: Irregular
P wave: At least 3 different shapes; sometimes no P at all on some beats
QRS interval: < 0.12
Cause: MI, medication side effects, hypoxia, vagal stimulation
Adverse Effects: Usually no ill effects
Treatment: Usually none; atropine or pacemaker if HR slow and symptoms
Multifocal Atrial Tachycardia
Rate: Mean rate > 100
Regularity: Irregular
P wave: At least 3 different shapes; sometimes no P at all on some beats
QRS interval: < 0.12
Cause: COPD
Adverse Effects: Decreased cardiac output at higher heart rates
Treatment: Betablockers or calcium channel blockers
PACs
Rate: Can occur at any rate
Regularity: Regular bu interrupted
P wave: Shaped differently from sinus Ps; often hidden in preceding T wave
QRS interval: < 0.12; QRS absent after nonconducted PAC
Cause: Stimulants, caffeine, hypoxia, heart disease, or normal
Adverse Effects: None if occassional; can be a sign of early heart failure
Treatment: Remove the causes; consider O2, digitalis, calcium channel blockers
Paroxysmal Atrial Tachycardia (PAT)
Rate: 161 - 250 once in atrial tach
Regularity: Regular but interrupted
P wave: Shaped differently from sinus Ps but same as each other
QRS interval: < 0.12
Cause: Stimulants, caffeine, hypoxia, heart disease, or normal
Adverse Effects: Decreased cardiac output; some people tolerate OK for a while
Treatment: Digitalis, amiodarone, calcium channel blockers, beta-blockers, sedation, O2, adenosine, electrical cardioversion
Atrial Flutter
Rate: Atria: 251-350; Ventricle: Varies
Regularity: Regular or irregular
P wave: None; flutter waves present (zigzag or sawtooth waves)
QRS interval: < 0.12
Cause: Heart disease, hypoxia, pulmonary embolus, lung disease, valve disease, thyroid storm
Adverse Effects: Tolerated OK at normal rate; decreased cardiac output at faster or slower rates
Treatment: Digitalis, amiodarone, calcium channel blockers, beta-blockers, consider O2, carotid massage, electrical cardioversion
Atrial fib
Rate: Atria: 350-700; Ventricle: Varies
Regularity: Irregularly irregular
P wave: None; fibrillatory waves present (waviness of the baseline)
QRS interval: < 0.12
Cause: MI, lung disease, valve disease, thyrotoxicosis
Adverse Effects: Decreased cardiac output;can cause blood clots in atria
Treatment: Digitalis, amiodarone, calcium channel blockers, beta-blockers, consider O2, electrical cardioversion, consider anticoagulation to prevent clots
SVT
Rate: > or = 130
Regularity: Regular
P wave: May be present but hard to see
QRS interval: < 0.12
Cause: Stimulants, caffeine hypoxia, heart disease, or normal
Adverse Effects: Decreased cardiac output; some people tolerate OK for a while
Treatment: Digitalis, amiodarone, calcium channel blockers, beta-blockers, sedation, O2, adenosine, electrical cardioversion
PJCs
Rate: Can occur at any rate
Regularity: Regular but interrupted
P wave: Inverted before or after QRS or hidden inside QRS
QRS interval: < 0.12
Cause: Stimulants, caffeine, hypoxia, heart disease, or normal
Adverse Effects: Usually no ill effects
Treatment: Usually none required
Junctional Bradycardia
Rate: < 40
Regularity: Regular
P wave: Inverted before or after QRS or hidden inside QRS
QRS interval: < 0.12
Cause: Vagal stimulation, hypoxia, sinus node ischemia, MI
Adverse Effects: Decreased cardiac output
Treatment: Pacemaker or atropine if symptoms; hold medications that can slow the HR, start O2
Junctional Rhythm
Rate: 40 - 60
Regularity: Regular
P wave: Inverted before or after QRS or hidden inside QRS
QRS interval: < 0.12
Cause: Vagal stimulation, hypoxia, sinus node ischemia, MI
Adverse Effects: Well tolerated if HR closer to 50-60; decreased cardiac output possible
Treatment: Pacemaker or atropine if symptoms; hold medications that can slow the HR, start O2
Accelerated Junctional
Rate: 60 - 100
Regularity: Regular
P wave: Inverted before or after QRS or hidden inside QRS
QRS interval: < 0.12
Cause: Heart disease, stimulant drugs, caffeine
Adverse Effects: Usually no ill effects
Treatment: Usually none needed
Junctional Tach
Rate:> 100
Regularity: Regular
P wave: Inverted before or after QRS or hidden inside QRS
QRS interval: < 0.12
Cause: Digitalis toxicity, heart disease, stimulants, SNS stimulation
Adverse Effects: Decreased cardiac output at faster heart rates
Treatment: Beta-blockers, calcium channel blockers, adenosine, consider O2 and electrical cardioversion
PVCs
Rate: Can occur at any rate
Regularity: Regular but interrupted
P wave: Usually none
QRS interval: > 0.12; wide and bizarre in shape
Cause: Hypoxia, MI, hypokalemia, low magnesium, caffeine, stimulants, stress
Adverse Effects: Occasional are no problem; can lead to lethal arrhythmias if frequent or after an MI
Treatment: Amiodarone, O2, lidocaine, atropine for bradycardic PVCs
Agonal Rhythm
Rate: < 20
Regularity: Irregular
P wave: None
QRS interval: > 0.12; wide and bizarre in shape
Cause: Profound cardiac or other damage, profound hypoxia
Adverse Effects: Shock, unconsiousness, death, if untreated
Treatment: CPR, atropine, epinephrine, dopamine, O2
Idioventricular Rhythm
Rate: 20 - 40
Regularity: Regular
P wave: None
QRS interval: > 0.12; wide and bizarre in shape
Cause: Massive cardiac or other damage hypoxia
Adverse Effects: Decreased Cardiac Output
Treatment: Atropine, epinephrine, dopamine, O2, pacemaker
AIVR
Rate: 40 - 100
Regularity: Usually regular- can be irregular at times
P wave: Dissociated if even present
QRS interval: > 0.12; wide and bizarre in shape
Cause: Most often seen during MI
Adverse Effects: Usually well tolerated
Treatment: Atropine, epinephrine, dopamine if HR low and symptoms
V-tach
Rate: 100 - 250
Regularity: Usually regular - can be irregular at times
P wave: Dissociated if even present
QRS interval: > 0.12; wide and bizarre in shape
Cause: Hypoxia, MI, hypokalemia, low magnesium, caffeine, stimulants, stress
Adverse Effects: May be tolerated OK for short bursts; can cause shock, unconsciousness, and death if untreated
Treatment: Amiodarone, lidocaine, O2, cardioversion or defib, CPR if no pulse
Torsades de pointes
Rate: > 200
Regularity: Regular or irregular
P wave: None seen
QRS interval: > 0.12; QRS oscillates around an axis
Cause: Medications such as quinidine or procainamide; hypoxia, MI, hypokalemia, low magnesium, caffeine, stimulants, stress
Adverse Effects: Circulatory collapse if sustained; tolerated OK for short bursts
Treatment: IV magnesium, overdrive pacing, cardioversion or defib, O2
V-fib
Rate: Cannot be counted
Regularity: None detectable
P wave: None
QRS interval: None; just a wavy baseline that looks like static
Cause: Hypoxia, MI, hypokalemia, low magnesium, caffeine, stimulants, stress
Adverse Effects: Cardiovascular collapse; no pulse, breathing, zero cardiac output
Treatment: Defibrillation, lidocaine, amiodarone, epinephrine, O2, CPR
Asystole
Rate: Zero
Regularity: None
P wave: None
QRS interval: None
Cause: Profound cardiac or other damage, hypoxia
Adverse Effects: Death if untreated
Treatment: Atropine, epinephrine, CPR, O2
P wave asystole
Rate: Zero
Regularity: Ps regular
P wave: Sinus Ps
QRS interval: None
Cause: Profound cardiac or other damage, hypoxia
Adverse Effects: Death if untreated
Treatment: Atropine, epinephrine, CPR, O2
First-degree AV block
Rate: Can occur at any rate
Regularity: Depends on underlying rhythm
P wave: Normal; one per QRS; all shaped the same
PR interval: > 0.20; constant
QRS interval: < 0.12
Cause: AV node ischemia, prolonged bundle branch depolarization time, digitalis toxicity, other medication side effects
Adverse Effects: Usually no ill effects
Treatment: Remove the cause
Mobitz I second-degree AV block (Wenckebach)
Rate: Atria: 60-100; Ventricle: less than atrial rate
Regularity: Regular but interrupted or irregular; groups of beats, then a pause
P wave: Normal; one not followed by a QRS; all shaped the same
PR interval: Gradually prolongs until a QRS is dropped
QRS interval: QRS < 0.12
Cause: MI, digitalis toxicity, medication side effects
Adverse Effects: Usually well tolerated, but watch for worsening AV block
Treatment: Pacemaker, atropine, epinephrine or dopamine if symptoms from low HR
Mobitz II second-degree AV block
Rate: Atria: 60-100: Ventricle: less than atrial rate
Regularity: Regular, regular but interrupted, or irregular
P wave: Normal; some not followed by a QRS
PR interval: Constant on the conducted beats
QRS interval: < 0.12 if block at AV node; > or = 0.12 if block at bundle branches
Cause: MI, conduction system lesion, hypoxia, medication side effects
Adverse Effects: Decreased cardiac output if HR slow
Treatment: Pacemaker, atropine, epinephrine, or dopamine, consider O2
2:1 AVB
Rate: Atria: 60-100; Ventricle: half the atrial rate
Regularity: Regular
P wave: Normal; 2 Ps to each QRS
PR interval: Constant on the conducted beats
QRS interval: < 0.12 if block at AV node; > or = 0.12 if block an bundle branches
Cause: MI, digitalis toxicity, conduction system lesion, hypoxia, medication side effects
Adverse Effects: Decreased cardiac output if HR slow
Treatment: Pacemaker, atropine, epinephrine or dopamine, consider O2
Third-degree AV block
Rate: Atria: 60-100; Ventricle: 20-60
Regularity: Regular
P wave: Normal; dissociated from QRS
PR interval: Varies
QRS interval: < 0.12 if AV node is the pacemaker; > 0.12 if ventricle is the pacemaker
Cause: MI, conduction system lesion, hypoxia, medication side effect
Adverse Effects: Decreased cardiac output if HR slow
Treatment: Pacemaker, atropine, epinephrine or dopamine, O2