arrhythmia broad overview

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Cardiac Arrhythmias Cardiac Arrhythmias Broad overview Broad overview DR. TAI AL AKAWY DR. TAI AL AKAWY Alexandria University Children’s Hospital Alexandria University Children’s Hospital

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Cardiac ArrhythmiasCardiac ArrhythmiasBroad overviewBroad overview

DR. TAI AL AKAWYDR. TAI AL AKAWYAlexandria University Children’s HospitalAlexandria University Children’s Hospital

DEFINITIONDEFINITION

The normal heart rate is regular and its range The normal heart rate is regular and its range depends on age, sex, exercise, etc.depends on age, sex, exercise, etc.

Change in the rate or regularity is called Change in the rate or regularity is called arrhythmiaarrhythmia

Pediatric dysrhythmiasPediatric dysrhythmiasKey pointsKey points

Vital to be aware of arrhythmias that occur in Vital to be aware of arrhythmias that occur in otherwise healthy childrenotherwise healthy children

Management is individualizedManagement is individualized Does child have history of heart disease?Does child have history of heart disease? Are symptoms present?Are symptoms present?

ETIOLOGYETIOLOGY

CONGENITALCONGENITAL::

Metabolic disorders of the mitochondria or Metabolic disorders of the mitochondria or fetal inflammation as in maternal SLE fetal inflammation as in maternal SLE

ACQUIREDACQUIRED::

Rheumatic fever, myocarditis, toxins(dipht.), Rheumatic fever, myocarditis, toxins(dipht.), theophylline, after surgical correction of CHDtheophylline, after surgical correction of CHD

ELECTRICAL CONDUCTIONELECTRICAL CONDUCTION

SINOATRIAL NODE (SA)SINOATRIAL NODE (SA) INTRAATRIAL FIBERINTRAATRIAL FIBER ATRIOVENTRICULAR (AV) NODEATRIOVENTRICULAR (AV) NODE BUNDLE OF HIS (COMMON BUNDLE)BUNDLE OF HIS (COMMON BUNDLE) BUNDLE BRANCHESBUNDLE BRANCHES PURKINJE FIBERSPURKINJE FIBERS

Sites of Disturbances in Impulse Formation or Conduction Leading to arrhythmias

SA Node

AV NodeHis-PurkinjeSystem

Pacemaker Hierarchy(Dominant vs Subsidiary/Escape Pacemakers)

SA Node(+Atria)

AV Junction(=AVN/His Bundle)

Ventricles(= Distal Purkinje System)

Intrinsic Rate of Firing

60-100 /min

40-60 /min

30-40 / min

REVIEW OF CONDUCTIONREVIEW OF CONDUCTION

CLASSIFICATON OF ARRHYTHMIAS CLASSIFICATON OF ARRHYTHMIAS

Sinus pacemakerSinus pacemaker: sinus arrhythmia, sinus : sinus arrhythmia, sinus tachycardia, sinus bradycardiatachycardia, sinus bradycardia

Ectopic pacemakerEctopic pacemaker::

ExtrasystolesExtrasystoles: premature atrial , junctional, : premature atrial , junctional, and ventricular contractions----and ventricular contractions----

Paroxysm-arrhythmiaParoxysm-arrhythmia( supraventricular ) ( supraventricular ) PAT ,atrial flutter , atrial fibrillation, ectopic PAT ,atrial flutter , atrial fibrillation, ectopic atrial tachycardia and accelerated junctional atrial tachycardia and accelerated junctional tachycardiatachycardia

VentricularVentricular : Ventricular tachycardia , and V. : Ventricular tachycardia , and V. fibrillationfibrillation

Brady arrhythmiaBrady arrhythmia( heart block)( heart block) Sinus arrest and SA blockSinus arrest and SA block Atrioventricular block (1Atrioventricular block (1stst ,2 ,2ndnd ,3 ,3rdrd degree block) degree block) Congenital complete atrioventricular blockCongenital complete atrioventricular block

Pediatric dysrhythmiasPediatric dysrhythmiasTreatment not requiredTreatment not required Treatment Treatment isis required required

Sinus arrhythmiaSinus arrhythmia Supraventricular tachycardiaSupraventricular tachycardia

Wandering atrial pacemakerWandering atrial pacemaker

Isolated premature atrial Isolated premature atrial contractionscontractionsIsolated premature Isolated premature ventricular contractionsventricular contractions

Ventricular tachycardiaVentricular tachycardia

First degree AV blockFirst degree AV block Third degree AV block with Third degree AV block with symptomssymptoms

Reproduced from Zitelli’s Atlas of Pediatric physical diagnosis, 2007, pg 140.

Sinus arrhythmiaSinus arrhythmia

Most common irregularity of heart rhythm Most common irregularity of heart rhythm seen in childrenseen in children

Normal variantNormal variant Reflects healthy interaction between Reflects healthy interaction between

autonomic respiratory and cardiac control autonomic respiratory and cardiac control activity in CNSactivity in CNS

Heart rate increases during inspiration and Heart rate increases during inspiration and decreases during exspirationdecreases during exspiration

Inspiration Expiration

SA nodal acceleration SA nodal deceleration

Sinus Arrhythmia

Sinus arrhythmiaSinus arrhythmia

Wandering atrial pacemakerWandering atrial pacemaker

Atrial pacemaker shifts from sinus node to Atrial pacemaker shifts from sinus node to another atrial siteanother atrial site

Normal variant, irregular rhythmNormal variant, irregular rhythm

Isolated PAC’sIsolated PAC’s

Premature atrial contractionsPremature atrial contractions Benign in absence of underlying heart dzBenign in absence of underlying heart dz Common in newborn periodCommon in newborn period Early p wave, sometimes with different morphology Early p wave, sometimes with different morphology

than a sinus p wavethan a sinus p wave Can be either:Can be either:

– Not conducted to ventricle, apparent pauseNot conducted to ventricle, apparent pause– Conducted to ventricle with aberrant or widened QRS Conducted to ventricle with aberrant or widened QRS

complex ( careful not to mix up with PVC’s)complex ( careful not to mix up with PVC’s)

Isolated PAC’sIsolated PAC’s

Premature Ventricular Contractions (PVC’s)Premature Ventricular Contractions (PVC’s)

Not very commonly seen in childrenNot very commonly seen in children Incidence of 0.3 to 2.2 %Incidence of 0.3 to 2.2 % Early, wide QRS complexesEarly, wide QRS complexes T waves in opposite direction of QRST waves in opposite direction of QRS Unifocal PVC’s are most encountered typeUnifocal PVC’s are most encountered type Bigeminy, sinus beat followed by PVC, Bigeminy, sinus beat followed by PVC,

repeating as a pattern, also frequently seenrepeating as a pattern, also frequently seen

PVC’sPVC’s

If unifocal, disappear with exercise, and associated If unifocal, disappear with exercise, and associated with structurally and functionally normal heart, then with structurally and functionally normal heart, then considered benign, no therapy neededconsidered benign, no therapy needed

PVC’s evaluationPVC’s evaluation

12 lead EKG, Echocardiogram12 lead EKG, Echocardiogram Perhaps Holter monitoringPerhaps Holter monitoring Brief exercise in office to see if ectopy Brief exercise in office to see if ectopy

suppressed or more frequentsuppressed or more frequent Multifocal or paired PVC’s more worrisomeMultifocal or paired PVC’s more worrisome Medications usually not neededMedications usually not needed Advise patients to avoid caffeine and other Advise patients to avoid caffeine and other

stimulantsstimulants

TachyarrhythmiasTachyarrhythmias

Tachyarrhythmias - ClassificationTachyarrhythmias - Classification Narrow complexNarrow complex: sinus tachycardia, : sinus tachycardia,

supraventricular tachycardia, atrial fluttersupraventricular tachycardia, atrial flutter Wide complexWide complex: ventricular tachycardia, : ventricular tachycardia,

supraventricular tachycardia with aberrant supraventricular tachycardia with aberrant intraventricular conduction (bundle block)intraventricular conduction (bundle block)

Tachyarrhythmias - SymptomsTachyarrhythmias - Symptoms GeneralGeneral: palpitations, lightheadedness, : palpitations, lightheadedness,

syncope, fatigue, SOB, chest painsyncope, fatigue, SOB, chest pain– Infants: poor feeding, tachypnea, irritability, Infants: poor feeding, tachypnea, irritability,

sleepiness, pallor, vomitingsleepiness, pallor, vomiting Hemodynamic instabilityHemodynamic instability: respiratory : respiratory

distress/failure, hypotension, poor end-distress/failure, hypotension, poor end-organ perfusion, altered LOC, sudden organ perfusion, altered LOC, sudden collapsecollapse

Tachyarrhythmias - CausesTachyarrhythmias - Causes 1ry: Underlying conduction abnormalities1ry: Underlying conduction abnormalities 2ry: Reversible 2ry: Reversible HHs & s & TTss

– HHypovolemiaypovolemia – – TToxinsoxins– HHypoxiaypoxia – – TTamponade amponade (cardiac)(cardiac)

– HH++ ions ions (acidosis)(acidosis) – – TTension pneumothoraxension pneumothorax– HHypoglycemiaypoglycemia – – TThrombosis hrombosis (coronary, pulmonary)(coronary, pulmonary)

– HHypothermiaypothermia – – TTraumarauma– HHypo/ypo/HHyperkalemiayperkalemia

Tachyarrhythmias - TypesTachyarrhythmias - Types Sinus tachycardiaSinus tachycardia

– Usually <220 bpm in infants, <180 bpm in Usually <220 bpm in infants, <180 bpm in childrenchildren

– P waves present and normal (upgoing in I, II, P waves present and normal (upgoing in I, II, AVF), narrow QRS, beat to beat variability AVF), narrow QRS, beat to beat variability

– Response to body’s need for increased cardiac Response to body’s need for increased cardiac output or oxygen delivery (ie: hypoxia, output or oxygen delivery (ie: hypoxia, hypovolemia, fever, pain, anemia)hypovolemia, fever, pain, anemia)

Tachyarrhythmias - TypesTachyarrhythmias - Types Supraventricular tachycardia Supraventricular tachycardia

– >220 bpm in infants, >180 bpm in children>220 bpm in infants, >180 bpm in children– Abrupt onset; occurs intermittentlyAbrupt onset; occurs intermittently– Usually narrow QRS, absent or abnormal P Usually narrow QRS, absent or abnormal P

waves, no beat to beat variabilitywaves, no beat to beat variability– Caused by accessory pathway reentry (ie: WPW), Caused by accessory pathway reentry (ie: WPW),

AV nodal reentry, ectopic atrial focusAV nodal reentry, ectopic atrial focus

Supraventricular tachycardiaSupraventricular tachycardia

Most common abnormal tachycardiaMost common abnormal tachycardia seen in seen in pediatric practicepediatric practice

Most common arrhythmia requiring Most common arrhythmia requiring treatmenttreatment in pediatric population in pediatric population

Most frequent age presentation: 1Most frequent age presentation: 1stst 3 months 3 months of life, 2of life, 2ndnd peaks at 8-10 and in adolescense peaks at 8-10 and in adolescense

Rapid, Rapid, regularregular, usually narrow QRS rhythm, , usually narrow QRS rhythm, originating above the ventricles originating above the ventricles

SVTSVT

Figure 5-42 Supraventricular tachycardia. Note a normal QRS complex tachycardia at a rate of 214 beats/minute without visible P waves.

EAT in an asymptomatic 8-month patient with EAT in an asymptomatic 8-month patient with abnormal P wave axis. Note merging of T and P wavesabnormal P wave axis. Note merging of T and P waves

SVTSVT

Older kids can describe a sensation of a fast Older kids can describe a sensation of a fast heart rate, palpitations, or chest tightnessheart rate, palpitations, or chest tightness

Hemodynamic compromise in newborns and Hemodynamic compromise in newborns and those with structural heart diseasethose with structural heart disease

Those with typical symptoms would benefit Those with typical symptoms would benefit from cardiac consultationfrom cardiac consultation

SVT - TreatmentSVT - Treatment Goal: Goal: identify unstable patients, differentiate from sinus identify unstable patients, differentiate from sinus

tachycardia, and terminate the rhythm tachycardia, and terminate the rhythm

Vagal maneuvers in stable patientsVagal maneuvers in stable patients

Adenosine if IV access readily availableAdenosine if IV access readily available Synchronized cardioversionSynchronized cardioversion

Amiodarone, Procainamide if above unsuccessfulAmiodarone, Procainamide if above unsuccessful Transesophageal atrial pacing can also be performedTransesophageal atrial pacing can also be performed

Tachyarrhythmias – ManagementTachyarrhythmias – Management

SVT with adequate perfusionSVT with adequate perfusion– Vagal maneuvers while preparing adenosineVagal maneuvers while preparing adenosine

SVT with poor perfusionSVT with poor perfusion– Immediate adenosine or cardioversionImmediate adenosine or cardioversion– AdenosineAdenosine

Rapid bolus then flush using proximal PIV or CVLRapid bolus then flush using proximal PIV or CVL 0.1 mg/kg; max 10.1 mg/kg; max 1stst dose 6 mg; additional 0.2 mg/kg if dose 6 mg; additional 0.2 mg/kg if

needed (max 2needed (max 2ndnd dose 12 mg) dose 12 mg)– Cardioversion (0.5-1 J/kg; sedate if possible)Cardioversion (0.5-1 J/kg; sedate if possible)

SVT - TreatmentSVT - Treatment

Need post conversion ECG Need post conversion ECG – identify those with WPW – identify those with WPW syndrome ( 25 % pts with SVT)syndrome ( 25 % pts with SVT)

Will also need an echo Will also need an echo – identify structural problems– identify structural problems Radiofrequency catheter ablationRadiofrequency catheter ablation

– Frontline treatmentFrontline treatment– Very effectiveVery effective– Cutoff points usually are 5 y.o. and 15 kg, unless severe SVTCutoff points usually are 5 y.o. and 15 kg, unless severe SVT

Observation and expectant managementObservation and expectant management MedicationsMedications

– Digoxin and beta blockers as first lineDigoxin and beta blockers as first line– Flecainide, sotalol, amiodaroneFlecainide, sotalol, amiodarone

Other SVT’sOther SVT’s

A flutter, A fib, ectopic atrial tachycardia, A flutter, A fib, ectopic atrial tachycardia, junctional tachycardiasjunctional tachycardias

Not commonly seen in pediatric patientsNot commonly seen in pediatric patients Adenosine does not terminate these rhythms, Adenosine does not terminate these rhythms,

originate above AV nodeoriginate above AV node Treatments: procainamide, amiodarone, Treatments: procainamide, amiodarone,

cardioversion, or ablationcardioversion, or ablation

SVT - WPWSVT - WPW

Figure 5-43 Wolff-Parkinson-White syndrome. Note the characteristic findings of a short P-R interval, slurred upstroke of QRS (delta wave), and prolongation of the QRS interval.

Tachyarrhythmias - TypesTachyarrhythmias - Types Atrial flutterAtrial flutter

– Sawtooth pattern on ECGSawtooth pattern on ECG– Atrial rate 350-400/min; ventricular rate variesAtrial rate 350-400/min; ventricular rate varies

ATRIAL FLUTTERATRIAL FLUTTER

ATRIAL ECTOPIC PACER FIRES AT A RATE OF 250-400/ MINATRIAL ECTOPIC PACER FIRES AT A RATE OF 250-400/ MIN OCCURS IN A VARIETY OF HEART DISEASES-OCCURS IN A VARIETY OF HEART DISEASES-

RHEUMATIC, CORONARY, HYPERTENSIVE, ALSO RHEUMATIC, CORONARY, HYPERTENSIVE, ALSO CARDIOMYOPATHY, HYPOXIA, HEART FAILURE, CARDIOMYOPATHY, HYPOXIA, HEART FAILURE,

MAY BE ASYMPTOMATIC OR HAVE PALPITATIONSMAY BE ASYMPTOMATIC OR HAVE PALPITATIONS MANAGEMENT-MANAGEMENT-

DIGITALIS, BETA BLOCKERS, CALCIUM CHANNEL DIGITALIS, BETA BLOCKERS, CALCIUM CHANNEL BLOCKERS, MAY USE CARDIOVERSIONBLOCKERS, MAY USE CARDIOVERSION

Atrial flutter in a newborn with atrial rate of 375 and Atrial flutter in a newborn with atrial rate of 375 and ventricular rate of 185 bpm. Note the typical ventricular rate of 185 bpm. Note the typical

“sawtooth” appearance and AV conduction 2:1“sawtooth” appearance and AV conduction 2:1

ATRIAL FIBRILLATIONATRIAL FIBRILLATION SEVERAL ECTOPIC FOCI CAUSING THE ATRIA SEVERAL ECTOPIC FOCI CAUSING THE ATRIA

TO QUIVER RATHER THAN CONTRACT. TO QUIVER RATHER THAN CONTRACT. RATE >400RATE >400 VENTRICULAR RATE DEPENDS ON THE VENTRICULAR RATE DEPENDS ON THE

NUMBER OF IMPULSES CONDUCTED THRU NUMBER OF IMPULSES CONDUCTED THRU THE AV NODETHE AV NODE

MANAGEMENT- DIG., BETA BLOCKERS, MANAGEMENT- DIG., BETA BLOCKERS, CALCIUM CHANNEL BLOCKERS, CALCIUM CHANNEL BLOCKERS, COUNTERSHOCKCOUNTERSHOCK

Atrial fibrillation in a 2½ year old asymptomatic patient. Atrial fibrillation in a 2½ year old asymptomatic patient. Note chaotic atrial waves with irregular ventricular Note chaotic atrial waves with irregular ventricular

responseresponse

AFAF

May ppt. heart failure and pul. OedemaMay ppt. heart failure and pul. Oedema Risk of thromboembolism and strokeRisk of thromboembolism and stroke Management: Management:

DC cardioversion: the treatment of choiceDC cardioversion: the treatment of choice

Drugs: calcium channel blockers , the best Drugs: calcium channel blockers , the best initial treatmentinitial treatment

Anticoagulant therapy is givento avoid Anticoagulant therapy is givento avoid thromboembolism and stroke before any thromboembolism and stroke before any managementmanagement

VENTRICULAR DYSRHYTHMIASVENTRICULAR DYSRHYTHMIAS

IMPULSE ORIGINATES IN THE VENTRICLESIMPULSE ORIGINATES IN THE VENTRICLES CAUSES- DRUG TOXICITY, HYPOXIA, CAUSES- DRUG TOXICITY, HYPOXIA,

HYPOTHERMIA, ELECTROLYE IMBALANCESHYPOTHERMIA, ELECTROLYE IMBALANCES

Ventricular tachycardiaVentricular tachycardia

Ventricular tachycardia: ( 3 or more PVC at Ventricular tachycardia: ( 3 or more PVC at >120 beat/ min)>120 beat/ min)– Wide QRS (>0.08 sec), P Wide QRS (>0.08 sec), P waves may be unidentifiable or not related to QRSwaves may be unidentifiable or not related to QRS– Caused by underlying heart disease, post-heart Caused by underlying heart disease, post-heart

surgery, myocarditis, cardiomyopathy, ↑QTc, surgery, myocarditis, cardiomyopathy, ↑QTc, ↑K↑K++, ↓Ca, ↓Ca++++, ↓Mg, ↓Mg++++, drug toxicity, drug toxicity

Ventricular tachycardiaVentricular tachycardia

Sustained V-tach is uncommon, needs workupSustained V-tach is uncommon, needs workup Regular Regular widewide complex tachycardia complex tachycardia Atrioventricular dissociation Atrioventricular dissociation Life threatening arryhthmiaLife threatening arryhthmia Often presents in those who have had open Often presents in those who have had open

heart surgical repair, or those with heart surgical repair, or those with cardiomyopathies, myocarditis, or tumorscardiomyopathies, myocarditis, or tumors

V-TachV-Tach Treatment: IV lidocaine, procainamide, Treatment: IV lidocaine, procainamide,

amiodaroneamiodarone If critically ill: synchronized cardioversionIf critically ill: synchronized cardioversion Long term: meds, ablation, or defibrillatorLong term: meds, ablation, or defibrillator

TREATMENTTREATMENT MANAGEMENT DEPENDS UPON SEVERITYMANAGEMENT DEPENDS UPON SEVERITY

IF STABLE – CONTINUE MONITORING, 12 LEAD IF STABLE – CONTINUE MONITORING, 12 LEAD ELECTROCARDIOGRAMELECTROCARDIOGRAM– FACTORS DETERMINING MEDICATIONS TO BE ADMINISTERED:FACTORS DETERMINING MEDICATIONS TO BE ADMINISTERED:

MONOMORPHIC OR POLYMORPHICMONOMORPHIC OR POLYMORPHIC EXISTENCE OF PROLONGED QT INTERVAL PRIOR TO ONSETEXISTENCE OF PROLONGED QT INTERVAL PRIOR TO ONSET HEART FUNCTION (NORMAL OR DECREASED)HEART FUNCTION (NORMAL OR DECREASED)

UNSTABLE- UNCONSCIOUS / WITHOUT A PULSE – TREAT UNSTABLE- UNCONSCIOUS / WITHOUT A PULSE – TREAT AS VENTRICULAR FIBRILLATION – AS VENTRICULAR FIBRILLATION – IMMEDIATE IMMEDIATE DEFIBRILLATIONDEFIBRILLATION

Ventricular fibrillationVentricular fibrillation Seen in children with ECG abnormalities such Seen in children with ECG abnormalities such

as as long QT syndromelong QT syndrome Cardiomyopathies, structural heart disease Cardiomyopathies, structural heart disease

causing ventricular dysfunctioncausing ventricular dysfunction Treatment: immediate defibrillation, CPRTreatment: immediate defibrillation, CPR

V-fibV-fib

Treatment: defibrillatorTreatment: defibrillator

TREATMENTTREATMENT IMMEDIATE DEFIBRILLATIONIMMEDIATE DEFIBRILLATION CPRCPR ERADICATING THE CAUSEERADICATING THE CAUSE VASOACTIVE AND ANTIARRHYTHMIC VASOACTIVE AND ANTIARRHYTHMIC

MEDICATIONS: IV amiodaron or lidocainMEDICATIONS: IV amiodaron or lidocain After recovery role out long Q-T syndrome After recovery role out long Q-T syndrome

and WPW syndromeand WPW syndrome

Long Q-T syndromeLong Q-T syndrome

FamilialFamilial: Genetic, Romano ward syndrome (AD): Genetic, Romano ward syndrome (AD)

Jervell-Lange-Nielsen: (AR) + cong. DeafnessJervell-Lange-Nielsen: (AR) + cong. Deafness

SporadicSporadic

AcquiredAcquired::

Drugs: terfenadine, astemizole when given Drugs: terfenadine, astemizole when given with erythromycin or ketoconazolewith erythromycin or ketoconazole

Marked electrolyte abnormalities ,CNS injury Marked electrolyte abnormalities ,CNS injury or starvationor starvation

Tachyarrhythmias - TypesTachyarrhythmias - Types Torsades de PointesTorsades de Pointes

– Variable polarity & amplitude of QRS, appearing to Variable polarity & amplitude of QRS, appearing to rotate around the ECG isoelectric linerotate around the ECG isoelectric line

– A type of polymorphic VTA type of polymorphic VT– Caused by long QT syndromes, ↓MgCaused by long QT syndromes, ↓Mg++++, drug , drug

toxicities (including antiarrhythmics as Amiodarone)toxicities (including antiarrhythmics as Amiodarone)– Can deteriorate to ventricular fibrillationCan deteriorate to ventricular fibrillation

Tachyarrhythmias - ManagementTachyarrhythmias - Management ABCsABCs If If pulsepulse → PALS tachycardia algorithms → PALS tachycardia algorithms

– Poor perfusion Poor perfusion → Pediatric Tachycardia With → Pediatric Tachycardia With Pulses and Poor Perfusion algorithmPulses and Poor Perfusion algorithm

– Adequate perfusion Adequate perfusion → Pediatric Tachycardia → Pediatric Tachycardia With Adequate Perfusion algorithmWith Adequate Perfusion algorithm

If no pulse If no pulse → PALS Pediatric Pulseless Arrest → PALS Pediatric Pulseless Arrest algorithmalgorithm

BradyarrhythmiasBradyarrhythmias

Bradyarrhythmias - SymptomsBradyarrhythmias - Symptoms GeneralGeneral: :

altered LOC, fatigue, lightheadedness, altered LOC, fatigue, lightheadedness, dizziness, syncopedizziness, syncope

Hemodynamic instabilityHemodynamic instability::

hypotension, poor end-organ perfusion, hypotension, poor end-organ perfusion, respiratory distress/failure, sudden collapserespiratory distress/failure, sudden collapse

Bradyarrhythmias - CausesBradyarrhythmias - Causes 1º: Abnormal pacemaker/conduction system 1º: Abnormal pacemaker/conduction system

(congenital or postsurgical injury), (congenital or postsurgical injury), cardiomyopathy, myocarditiscardiomyopathy, myocarditis

2º: Reversible 2º: Reversible HHs & s & TTs: s: – HHypoxiaypoxia – – HHypotensionypotension – – HH++ ions ions (acidosis) (acidosis)

– HHeart blockeart block – – HHypothermia ypothermia – – HHyperkalemiayperkalemia– TTrauma rauma (head) (head)

– TToxins/drugs oxins/drugs (Ca(Ca++++ channel blockers, channel blockers, ββ-adrenergic blockers, digoxin, opioids) -adrenergic blockers, digoxin, opioids)

Bradyarrhythmias - TypesBradyarrhythmias - Types Sinus bradycardiaSinus bradycardia

– Physiologic (ie: sleep, athletes) vs. pathologic (ie: Physiologic (ie: sleep, athletes) vs. pathologic (ie: infection, drugs, hypoglycemia, hypothyroidism, infection, drugs, hypoglycemia, hypothyroidism, ↑ICP)↑ICP)

Sinus node blockSinus node block– Subsidiary pacemakers lead to atrial, junctional, & Subsidiary pacemakers lead to atrial, junctional, &

idioventricular escape rhythmsidioventricular escape rhythms

↓Junctional beat

Sinus Bradycardia

II

P wave upright in leads I and II, just as in normal sinus rhythm

Causes of Sinus BradycardiaCauses of Sinus Bradycardia

Increased vagal toneIncreased vagal tone Drugs: beta blockers, calcium channel Drugs: beta blockers, calcium channel

blockers, amiodarone, digoxin (indirect effect) blockers, amiodarone, digoxin (indirect effect) Myocardial ischemia/infarctionMyocardial ischemia/infarction HypothyroidismHypothyroidism ““Sick sinus syndrome” - degenerative/fibrotic Sick sinus syndrome” - degenerative/fibrotic

atrial processatrial process

AV Block - DefinitionsAV Block - Definitions

First Degree:First Degree: Prolonged conduction time Prolonged conduction time

Second Degree:Second Degree: Intermittent non-conduction Intermittent non-conduction

Third Degree:Third Degree: Persistent non-conduction Persistent non-conduction

First Degree AV Block (PR > .20 sec [1 big box])

II

P P P

.36

Site of delay most commonly the AV node, but may be localized to the His-Purkinje system

First degree AV blockFirst degree AV block

Diseases that can be associated with first Diseases that can be associated with first degree AV block: rheumatic fever, rubella, degree AV block: rheumatic fever, rubella, mumps, hypothermia, cardiomyopathy, mumps, hypothermia, cardiomyopathy, electrolyte disturbanceselectrolyte disturbances

Second Degree AV Block - Type I (Wenkebach or Mobitz I Block)

P P P P

Block

II

• Note PR ↑ prior to block and ↓ post-block

• Characteristic of AV nodal site of block

II

Block

P P P PP

Second Degree AV Block - Type I(Wenkebach or Mobitz I Block)

II

P P P P P P

Second Degree AV Block - Type II (Mobitz II)

• Example of 3:2 conduction ratio; general pattern, n:n-1• Note fixed PR for all conducted beats• Characteristic of His-Purkinje system site of block

Block Block

Second Degree AV Block - Type II

P P P P P

4:3 conduction ratio

Block

Third degree AV blockThird degree AV block

= complete heart block= complete heart block Most common cause of abnormal bradycardia Most common cause of abnormal bradycardia

in infants and childrenin infants and children Complete disassociation between P waves and Complete disassociation between P waves and

QRS complexesQRS complexes

Third degree AV blockThird degree AV block

Can be congenital – in this case it is strongly Can be congenital – in this case it is strongly associated with associated with maternal SLEmaternal SLE

Mother of an infant should be worked upMother of an infant should be worked up Most common structural heart defect Most common structural heart defect

associated is corrected transposition of great associated is corrected transposition of great vesselsvessels

Third degree AV blockThird degree AV block

May be asymptomatic – follow clinicallyMay be asymptomatic – follow clinically Slower the heart rate, and wide QRS escape Slower the heart rate, and wide QRS escape

rhythms place into high risk grouprhythms place into high risk group May need implantable pacemaker: significant May need implantable pacemaker: significant

bradycardias, syncope, exercise intolerance, bradycardias, syncope, exercise intolerance, ventricular arrhythmias, structural diseaseventricular arrhythmias, structural disease

Possible acute treatment: isoproterenolPossible acute treatment: isoproterenol

Third degree AV blockThird degree AV block

1st degree heart block

2nd degree heart block, Mobitz I

2nd degree heart block, Mobitz II

3rd degree heart block

P P P’ P’

Sinus bradycardia → Sinus arrest → Slow junctional escape rhythm

(with retrograde p waves)

Sinus Arrest

Tachycardia-Bradycardia (Form of “Sick Sinus”) Syndrome

Atrial Flutter

Sinus arrest Junctional escape (tardy)

Atrial Flutterterminates

Sinus Arrest → Asystole

Sinus rhythm

Sinus brady.→ Sinus arrest→ V. escape rhythm

Failure of V. escape rhythm→ Asystole

P P P

P P P P

P

Causes of SA Block and Sinus Causes of SA Block and Sinus Pauses/ArrestPauses/Arrest

Increased vagal tone (very intense for sinus Increased vagal tone (very intense for sinus arrest)arrest)

Drugs: beta blockers, calcium channel Drugs: beta blockers, calcium channel blockers, amiodarone, digoxin (indirect effect)blockers, amiodarone, digoxin (indirect effect)

Myocardial ischemia/infarctionMyocardial ischemia/infarction Sick sinus syndromeSick sinus syndrome Sequela of open heart surgery Sequela of open heart surgery

Bradyarrhythmias - ManagementBradyarrhythmias - Management Stable patients:Stable patients:

– 12 lead EKG, +/- labs, consult cardiology12 lead EKG, +/- labs, consult cardiology

Unstable patients:Unstable patients:– ABCsABCs– PALS Pediatric Bradycardia AlgorithmPALS Pediatric Bradycardia Algorithm

Address reversible causes (Hs & Ts)Address reversible causes (Hs & Ts)

VENTRICULAR ASYSTOLEVENTRICULAR ASYSTOLE

ABSENCE OF:ABSENCE OF:– QRSQRS– HEARTBEATHEARTBEAT– PALPABLE PULSEPALPABLE PULSE– RESPIRATIONRESPIRATION

ETIOLOGYETIOLOGY HYPOXIAHYPOXIA ACIDOSISACIDOSIS ELECTROLYTE IMBALANCEELECTROLYTE IMBALANCE DRUG OVERDOSEDRUG OVERDOSE HYPOTHERMIAHYPOTHERMIA

TREATMENTTREATMENT

CARDIOPULMONARY RESUSCITATIONCARDIOPULMONARY RESUSCITATION INTUBATIONINTUBATION INTRAVENOUS ACCESSINTRAVENOUS ACCESS TRANSCUTANEOUS PACINGTRANSCUTANEOUS PACING EPINEPHRINEEPINEPHRINE ATROPINEATROPINE

ADJUNCTIVE MODALITIES AND ADJUNCTIVE MODALITIES AND MANAGEMENTMANAGEMENT

TREATMENT DEPENDS UPON TREATMENT DEPENDS UPON – WHETHER THE DYSRHYTHMIA IS ACUTE OR WHETHER THE DYSRHYTHMIA IS ACUTE OR

CHRONICCHRONIC– THE CAUSE OF THE DYSRHYTHMIA AND ITS THE CAUSE OF THE DYSRHYTHMIA AND ITS

POTENTIAL HEMODYNAMIC EFFECTS POTENTIAL HEMODYNAMIC EFFECTS

PACERSPACERS AN ELECTRICAL IMPULSE THAT STIMULATES THE AN ELECTRICAL IMPULSE THAT STIMULATES THE

MYOCARDIUM TO DEPOLARIZE, INITIATING A MYOCARDIUM TO DEPOLARIZE, INITIATING A HEARTBEATHEARTBEAT

MAY BE DEMAND, FIXED, OR RATE RESPONSIVEMAY BE DEMAND, FIXED, OR RATE RESPONSIVE MAY BE TEMPORARY OR PERMANENTMAY BE TEMPORARY OR PERMANENT PACER SPIKE NOTED ON ECGPACER SPIKE NOTED ON ECG

INDICATIONSINDICATIONS A SLOWER A SLOWER THAN NORMAL IMPULSE THAN NORMAL IMPULSE

FORMATION OR A FORMATION OR A CONDUCTIONCONDUCTION DISTURBANCE THAT CAUSES SYMPTOMSDISTURBANCE THAT CAUSES SYMPTOMS

MAY BE USED TO TREAT MAY BE USED TO TREAT TACHYDYSRHYTHMIASTACHYDYSRHYTHMIAS THAT DO NOT THAT DO NOT RESPOND TO MEDICATION THERAPYRESPOND TO MEDICATION THERAPY

REFERENCESREFERENCES Doniger SJ, Sharieff GQ. Pediatric dysarrhythmias. Pediatr Clin North Doniger SJ, Sharieff GQ. Pediatric dysarrhythmias. Pediatr Clin North

Am. 2006;53:85–105.Am. 2006;53:85–105. Ludormirsky A, Garson A., Jr . SupraventricularTachycardias. In: Gillette A Ludormirsky A, Garson A., Jr . SupraventricularTachycardias. In: Gillette A

Jr, editor. Pediatric Arrhythmias: electrophysiology and Jr, editor. Pediatric Arrhythmias: electrophysiology and pacing. Philadelphia: WB Saunders; 1990. pp. 380–426.pacing. Philadelphia: WB Saunders; 1990. pp. 380–426.

Allen HD, Driscoll DJ, Shaddy RE, Feltes TF. 7th ed. Philadelphia (PA): Allen HD, Driscoll DJ, Shaddy RE, Feltes TF. 7th ed. Philadelphia (PA): Lippincott Williams and Wilkins; 2008. Moss and Adams’ Heart Disease in Lippincott Williams and Wilkins; 2008. Moss and Adams’ Heart Disease in infants, children and Adolescents.infants, children and Adolescents.

Walsh WP, Berul CI, Triedman JK. Cardiac Arrhythmias. In: Keane JF, Lock Walsh WP, Berul CI, Triedman JK. Cardiac Arrhythmias. In: Keane JF, Lock JE, Fyler DC, editors.Nadas’ Pediatric Cardiology. 2nd ed. Philadelphia JE, Fyler DC, editors.Nadas’ Pediatric Cardiology. 2nd ed. Philadelphia (PA): Elsevier Inc; 2006.(PA): Elsevier Inc; 2006.

Zeigler VL. Pediatric cardiac arrhythmias resulting in hemodynamic Zeigler VL. Pediatric cardiac arrhythmias resulting in hemodynamic compromise. Crit Care Nurs Clin North Am. 2005;17:77–95. compromise. Crit Care Nurs Clin North Am. 2005;17:77–95.

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