Pacemakers and AICD ’ s Emergency Medicine Ryan Ngiam

PacemakersPacemakersandand

AICD’sAICD’s

Emergency MedicineEmergency Medicine

Ryan NgiamRyan Ngiam

Historical PerspectiveHistorical Perspective

1905 – Einthoven1905 – Einthoven Published first two human AV block using string Published first two human AV block using string

galvanometergalvanometer

1958 – Senning and Elmqvist1958 – Senning and Elmqvist Asynchronous (VVI) pacemaker implanted by Asynchronous (VVI) pacemaker implanted by

thoracostomy and functioned for 3 hoursthoracostomy and functioned for 3 hours Arne LarssonArne Larsson

First pacemaker patientFirst pacemaker patientUsed 23 pulse generators and 5 electrode systemsUsed 23 pulse generators and 5 electrode systemsDied 2001 at age 86 of cancerDied 2001 at age 86 of cancer


1960 – First atrial triggered pacemaker1960 – First atrial triggered pacemaker

1964 – First on demand pacemaker (DVI)1964 – First on demand pacemaker (DVI)

1977 – First atrial and ventricular demand 1977 – First atrial and ventricular demand pacing (DDD)pacing (DDD)

1980 – Griffin published first successful 1980 – Griffin published first successful pacemaker intervention for pacemaker intervention for supraventricular tachycardiassupraventricular tachycardias


1981 – Rate responsive pacing by QT 1981 – Rate responsive pacing by QT interval, respiration, and movementinterval, respiration, and movement

1994 – Cardiac resynchronization pacing1994 – Cardiac resynchronization pacing

1998 – Automatic capture detection1998 – Automatic capture detection

NowNow Approximately 3 million with pacemakersApproximately 3 million with pacemakers Approximately 1 million with ICD deviceApproximately 1 million with ICD device

Pacemaker BasicsPacemaker Basics

Provides electrical stimuli to cause cardiac Provides electrical stimuli to cause cardiac contraction when intrinsic cardiac activity contraction when intrinsic cardiac activity is inappropriately slow or absentis inappropriately slow or absent

Sense intrinsic cardiac electric potentialsSense intrinsic cardiac electric potentials

ICD BasicsICD Basics

Designed to treat a cardiac tachydysrythmiaDesigned to treat a cardiac tachydysrythmiaPerforms cardioversion/defibrillationPerforms cardioversion/defibrillation Ventricular rate exceeds programmed cut-off Ventricular rate exceeds programmed cut-off

raterate

ATP (antitachycardia pacing)ATP (antitachycardia pacing) Overdrive pacing in an attempt to terminate Overdrive pacing in an attempt to terminate

ventricular tachycardiasventricular tachycardias

Some have pacemaker function (combo Some have pacemaker function (combo devices)devices)

Pacemaker and ICD BasicsPacemaker and ICD Basics

Pulse GeneratorsPulse Generators Placed subcutaneously or submuscularlyPlaced subcutaneously or submuscularly Connected to leadsConnected to leads BatteryBattery

Most commonly lithium-iodide typeMost commonly lithium-iodide type

Life span 5 to 8 yearsLife span 5 to 8 years

Output voltage decreases graduallyOutput voltage decreases gradually Makes sudden battery failure unlikelyMakes sudden battery failure unlikely


AsynchronousAsynchronous Fixed rateFixed rate Impulse produced at a set rateImpulse produced at a set rate No relation to patients intrinsic cardiac activityNo relation to patients intrinsic cardiac activity Susceptible to Torsades if impulse coincides Susceptible to Torsades if impulse coincides

with t wavewith t wave


SynchronousSynchronous Demand modeDemand mode Sensing circuit searches for intrinsic Sensing circuit searches for intrinsic

depolarization potentialdepolarization potential If absent, a pacing response is generatedIf absent, a pacing response is generated Can mimic intrinsic electrical activity pattern of Can mimic intrinsic electrical activity pattern of

the heartthe heart

Pacemaker NomenclaturePacemaker NomenclatureII IIII IIIIII IVIV VVChamber Chamber PacedPaced

Chamber Chamber SensedSensed

Response to Response to SensingSensing

Rate Modulation, Rate Modulation, ProgrammabilityProgrammability

Anti-Anti-tachycardia tachycardia FeaturesFeatures

A=AtriumA=Atrium A=AtriumA=Atrium T=TriggeredT=Triggered P=SimpleP=Simple P=PacingP=Pacing

V=VentricleV=Ventricle V=VentricleV=Ventricle I=InhibitedI=Inhibited M=Multi-M=Multi-programmableprogrammable

S=ShockS=Shock

D=DualD=Dual D=DualD=Dual D=DualD=Dual R=Rate AdaptiveR=Rate Adaptive D=DualD=Dual

O=NoneO=None O=NoneO=None O=NoneO=None C=CommunicatingC=Communicating

O=NoneO=None

Pacemaker NomenclaturePacemaker Nomenclature

11stst letter – chamber paced letter – chamber paced

22ndnd letter – chamber sensed letter – chamber sensed

33rdrd letter – Response to chamber sensed letter – Response to chamber sensed

ExamplesExamples

VVIVVI Paces ventriclePaces ventricle Senses ventricleSenses ventricle Inhibited by a sensed ventricular eventInhibited by a sensed ventricular event

Pacing Nomenclature Pacing Nomenclature ExamplesExamples

AATAAT Paces atriaPaces atria Senses atriaSenses atria Triggers generator to fire if atria sensedTriggers generator to fire if atria sensed

DDDDDD Paces atria and ventriclePaces atria and ventricle Senses atria and ventricleSenses atria and ventricle Atrial triggered and ventricular inhibitedAtrial triggered and ventricular inhibited EKG – 2 spikesEKG – 2 spikes

Atrial Spike Ventricular SpikeDDDDDD

Pacemaker Lead SystemPacemaker Lead System

Endocardial leads placed via central Endocardial leads placed via central accessaccess Placed in right ventricle and/or atriaPlaced in right ventricle and/or atria

Fixed to the endocardium via screws or Fixed to the endocardium via screws or tinestines

Experimental pacing systemsExperimental pacing systems 2 atrial leads (minimize afib)2 atrial leads (minimize afib) Biventricular pacingBiventricular pacing

Magnet InhibitionMagnet Inhibition

Closes an internal reed switchCloses an internal reed switch Causes sensing to be inhibitedCauses sensing to be inhibited Temporarily turns pacemaker into Temporarily turns pacemaker into

“asynchronous” mode (set rate)“asynchronous” mode (set rate)

Does NOT turn pacemaker offDoes NOT turn pacemaker off

Rate can confer info regarding battery lifeRate can confer info regarding battery life Distinct rates for BOL, ERI, EOLDistinct rates for BOL, ERI, EOL

Pacemaker IndicationsPacemaker Indications

Absolute indicationsAbsolute indications Sick sinus syndromeSick sinus syndrome Symptomatic sinus bradycardiaSymptomatic sinus bradycardia Tachy-brady syndromeTachy-brady syndrome Afib with slow ventricular responseAfib with slow ventricular response 33rdrd degree heart block degree heart block Chronotropic incompetenceChronotropic incompetence

Inability to increase heart rate to match exerciseInability to increase heart rate to match exercise Prolonged QT syndromeProlonged QT syndrome


33rdrd Degree heart block Degree heart block


Relative indicationsRelative indications CardiomyopathyCardiomyopathy

DilatedDilated

HypertrophicHypertrophic Severe refractory neurocardiogenic syncopeSevere refractory neurocardiogenic syncope Paroxysmal atrial fibrillationParoxysmal atrial fibrillation

ICD IndicationsICD Indications

GenerallyGenerally Used in cases where there was a previous Used in cases where there was a previous

cardiac arrestcardiac arrest Or, patients with undetermined origin or Or, patients with undetermined origin or

continued VT or VF despite medical continued VT or VF despite medical interventionsinterventions

Pacemaker ComplicationsPacemaker Complications

EKG abnormalities due toEKG abnormalities due to Failure to outputFailure to output Failure to captureFailure to capture Sensing abnormalitiesSensing abnormalities Operative failuresOperative failures

Pacemaker Failure to OutputPacemaker Failure to Output

DefinitionDefinition No pacing spike present despite indication to No pacing spike present despite indication to

pacepace

EtiologyEtiology Battery failure, lead fracture, break in lead Battery failure, lead fracture, break in lead

insulation, oversensing, poor lead connection, insulation, oversensing, poor lead connection, “cross-talk”“cross-talk”

Atrial output is sensed by ventricular leadAtrial output is sensed by ventricular lead

Pacemaker Failure to CapturePacemaker Failure to Capture

DefinitionDefinition Pacing spike is not followed by either an atrial Pacing spike is not followed by either an atrial

or ventricular complexor ventricular complex

EtiologyEtiology Lead fracture or dislodgement, break in lead Lead fracture or dislodgement, break in lead

insulation, elevated pacing threshold, MI at insulation, elevated pacing threshold, MI at lead tip, drugs, metabolic abnormalities, lead tip, drugs, metabolic abnormalities, cardiac perforation, poor lead connectioncardiac perforation, poor lead connection

Pacemaker Sensing Pacemaker Sensing AbnormalitiesAbnormalities

OversensingOversensing Senses noncardiac electrical activity and is Senses noncardiac electrical activity and is

inhibited from correctly pacinginhibited from correctly pacing EtiologyEtiology

Muscular activity (diaphragm or pecs), EMI, cell Muscular activity (diaphragm or pecs), EMI, cell phone held within 10cm of pulse generatorphone held within 10cm of pulse generator

UndersensingUndersensing Incorrectly misses intrinsic depolarization and Incorrectly misses intrinsic depolarization and

pacespaces EtiologyEtiology

Poor lead positioning, lead dislodgement, magnet Poor lead positioning, lead dislodgement, magnet application, low battery states, MIapplication, low battery states, MI

Pacemaker Operative FailuresPacemaker Operative Failures

Due to pacemaker placementDue to pacemaker placement PneumothoraxPneumothorax PericarditisPericarditis Perforated atrium or ventriclePerforated atrium or ventricle Dislodgement of leadsDislodgement of leads Infection or erosion of pacemaker pocketInfection or erosion of pacemaker pocket Infective endocarditis (rare)Infective endocarditis (rare) Venous thrombosisVenous thrombosis

Pacemaker ComplicationsPacemaker Complications

Pacemaker syndromePacemaker syndrome Patient feels worse after pacemaker Patient feels worse after pacemaker

placementplacement Presents with progressive worsening of CHF Presents with progressive worsening of CHF

symptomssymptoms Due to loss of atrioventricular synchrony, Due to loss of atrioventricular synchrony,

pathway now reversed and ventricular origin pathway now reversed and ventricular origin of beatof beat

Impact on ALS protocolsImpact on ALS protocols

Not manyNot many Can defibrillateCan defibrillate Sternal paddles should be placed a safe Sternal paddles should be placed a safe

distance (10 cm) from pulse generatordistance (10 cm) from pulse generator In case of MIIn case of MI

May require temporary transcutaneous pacingMay require temporary transcutaneous pacing

ICD ComplicationsICD Complications

Similar to pacemaker complicationsSimilar to pacemaker complications Operative failuresOperative failures

Same as pacemakersSame as pacemakers Sensing and pacing failuresSensing and pacing failures Inappropriate cardioversionInappropriate cardioversion Ineffective cardioversion/defibrillationIneffective cardioversion/defibrillation Device deactivationDevice deactivation

ICD Sensing failuresICD Sensing failures

Similar to pacmakersSimilar to pacmakers OversensingOversensing UndersensingUndersensing

Appropriate failure to treatAppropriate failure to treat Programmed cut off at 180 bpmProgrammed cut off at 180 bpm If V Tach occurs at 160 bpms, appropriately If V Tach occurs at 160 bpms, appropriately

fails to cardiovertfails to cardiovert

ICD Inappropriate CardioversionICD Inappropriate Cardioversion

Most frequent complicationsMost frequent complicationsProvokes pain and anxiety in ptsProvokes pain and anxiety in ptsConsider whenConsider when Pt is in afibPt is in afib

With ventricular response > programmed cut offWith ventricular response > programmed cut off Received multiple shocks in rapid successionReceived multiple shocks in rapid succession

EtiologyEtiology Afib, T-wave oversensing, lead fracture, insulation Afib, T-wave oversensing, lead fracture, insulation

breakage, MRI, EMIbreakage, MRI, EMI

ICD Inappropriate CardioversionICD Inappropriate Cardioversion

TreatmentTreatment Magnet over ICD inhibits further shocksMagnet over ICD inhibits further shocks Does NOT inhibit bradycardiac pacingDoes NOT inhibit bradycardiac pacing

NoteNote Some older devices produce beep with each QRSSome older devices produce beep with each QRS If left on for >30 seconds, ICD disabled and continous If left on for >30 seconds, ICD disabled and continous

beepbeep To reactivate, lift off magnet and then replace for > 30 To reactivate, lift off magnet and then replace for > 30

seconds, beep will return with each QRSseconds, beep will return with each QRS

ICD Failure to Deliver ICD Failure to Deliver CardioversionCardioversion

EtiologyEtiology Failure to sense, lead fracture, EMI, Failure to sense, lead fracture, EMI,

inadvertent ICD deactivationinadvertent ICD deactivation

ManagementManagement External defibrillation and cardioversionExternal defibrillation and cardioversion

Do not withhold therapy for fear of damaging ICDDo not withhold therapy for fear of damaging ICDIf pt’s internal defibrillator activates during chest If pt’s internal defibrillator activates during chest compressions, you may feel a mild shock (no compressions, you may feel a mild shock (no reports of deaths related to this)reports of deaths related to this)

Antidysrhymthic medicationsAntidysrhymthic medications

ICD Ineffective CardioversionICD Ineffective Cardioversion

EtiologyEtiology Inadequate energy outputInadequate energy output Rise in the defibrillation thresholdRise in the defibrillation threshold MI at the lead siteMI at the lead site Lead fractureLead fracture Insulation breakageInsulation breakage

Pre-programmed set of therapies per dysrythmiaPre-programmed set of therapies per dysrythmia Manufacturer specificManufacturer specific Once number of attempts reached, will not deliver further Once number of attempts reached, will not deliver further

shocks until new episode is declaredshocks until new episode is declared

Electromagnetic InterferenceElectromagnetic Interference

Can interfere with function of pacemaker Can interfere with function of pacemaker or ICDor ICD

Device misinterprets the EMI causingDevice misinterprets the EMI causing Rate alterationRate alteration Sensing abnormalitiesSensing abnormalities Asynchronous pacingAsynchronous pacing Noise reversionNoise reversion ReprogrammingReprogramming


ExamplesExamples Metal detectorsMetal detectors Cell phonesCell phones High voltage power linesHigh voltage power lines Some home appliances (microwave)Some home appliances (microwave)


Intensity of electromagnetic field Intensity of electromagnetic field decreases inversely with the square of the decreases inversely with the square of the distance from the sourcedistance from the source

Newer pacemakers and ICDs are being Newer pacemakers and ICDs are being built with increased internal shieldingbuilt with increased internal shielding

Case 1Case 1

CC: Chills, rigorsCC: Chills, rigorsHPI:HPI: 65 yom c/o fevers, chills, rigors x 1 day. Positive n/v 65 yom c/o fevers, chills, rigors x 1 day. Positive n/v

and anorexia. Pt states he had recent pacemaker and anorexia. Pt states he had recent pacemaker insertion 4 days ago for an arrhythmia.insertion 4 days ago for an arrhythmia.

PMH:PMH: HTNHTN ArrythmiaArrythmia HypercholesterolemiaHypercholesterolemia

PSHx:PSHx: As stated aboveAs stated above

Case 1Case 1

Physical examPhysical exam Temp 101.2, HR 110, BP 90/55Temp 101.2, HR 110, BP 90/55 EKGEKG

Diagnosis?Diagnosis?

Case 1Case 1

Pocket InfectionPocket InfectionPacemaker insertion is a surgical Pacemaker insertion is a surgical procedureprocedure 1% risk for bacteremia1% risk for bacteremia 2% risk for pocket infection2% risk for pocket infection

Usually occurs within 7 days of pacemaker Usually occurs within 7 days of pacemaker insertioninsertionMay have tenderness and redness over May have tenderness and redness over pacemaker sitepacemaker site

Case 2Case 2

CC: SOBCC: SOBHPI: HPI: 65 yom states he had onset of shortness of breath 65 yom states he had onset of shortness of breath

and left sided pleuritic chest pain. Pt states he awoke and left sided pleuritic chest pain. Pt states he awoke with pain and difficulty breathing. Had pacemaker with pain and difficulty breathing. Had pacemaker placed yesterday.placed yesterday.

PMHx:PMHx: HTN, Diabetes, Hypercholesterolemia, Arrythmia, HTN, Diabetes, Hypercholesterolemia, Arrythmia,

CADCAD

PSHx:PSHx: Pacemaker, left knee surgery, b/l cataractPacemaker, left knee surgery, b/l cataract

Case 2Case 2

Physical ExamPhysical Exam BP 146/85, HR 80s, RR 30s, O2 Sat 88%BP 146/85, HR 80s, RR 30s, O2 Sat 88% LungsLungs

Decreased breath sounds on leftDecreased breath sounds on left EKGEKG


Case 2Case 2

PneumothoraxPneumothorax

Occurs during cannulation of central veinsOccurs during cannulation of central veins

IncidenceIncidence Cardiologist dependentCardiologist dependent

TreatmentTreatment Small or asymptomatic – observationSmall or asymptomatic – observation Large or symptomatic – Chest tubeLarge or symptomatic – Chest tube

Case 3Case 3

CC: Cardiac arrestCC: Cardiac arrestHPI: 59 yom found on couch. Wife states HPI: 59 yom found on couch. Wife states they were watching TV when patient let they were watching TV when patient let out a moan and then became out a moan and then became unconscious. She states, he has a bad unconscious. She states, he has a bad heart and had “something” put in a few heart and had “something” put in a few years ago.years ago.PMHx: unknownPMHx: unknownMeds: bottles in bathroomMeds: bottles in bathroom

Case 3Case 3

Physical ExamPhysical Exam Airway patent, no visible chest rise, no pulsesAirway patent, no visible chest rise, no pulses Generally: cool, clammy, diaphoreticGenerally: cool, clammy, diaphoretic EKG:EKG:


Case 3Case 3

Cardiac Arrest with ICD (V-fib)Cardiac Arrest with ICD (V-fib)

2% annual incidence with ICD2% annual incidence with ICD

EtiologyEtiology ICD delivered predetermined shocks for ICD delivered predetermined shocks for

identified event and patient failed to respondidentified event and patient failed to respond ICD failed to recognize event and failed to ICD failed to recognize event and failed to

shock appropriatelyshock appropriatelyFailure to sense, lead fracture, EMI, inadvertent Failure to sense, lead fracture, EMI, inadvertent ICD deactivationICD deactivation

Case 3Case 3

Cardiac Arrest with ICDCardiac Arrest with ICD Treat using ACLS protocolsTreat using ACLS protocols Secure airwaySecure airway CPRCPR Defibrillate/shock as warranted Defibrillate/shock as warranted

Keep sternal pad 10 cm away from pulse Keep sternal pad 10 cm away from pulse generatorgenerator

MedsMeds

QuestionsQuestions

ReferencesReferences

EmedicineEmedicine http://www.emedicine.com/emerg/topic805.htmhttp://www.emedicine.com/emerg/topic805.htm

Minish, Travis. Pacemaker Emergencies.Minish, Travis. Pacemaker Emergencies. http://www.cgi.ualberta.ca/emergency/rounds/files/pacers3.ppt http://www.cgi.ualberta.ca/emergency/rounds/files/pacers3.ppt

The Implantable Pacemaker, a short historical overview.The Implantable Pacemaker, a short historical overview. http://igitur-archive.library.uu.nl/dissertations/2006-0426-200006/c1.pdf http://igitur-archive.library.uu.nl/dissertations/2006-0426-200006/c1.pdf

Healthy HeartsHealthy Hearts http://www.healthyhearts.com/pacemaker.htmhttp://www.healthyhearts.com/pacemaker.htm

MedtronicMedtronic http://www.medtronic.com/patients/heart.htmlhttp://www.medtronic.com/patients/heart.html

Shelton State UniversityShelton State University http://www.sheltonstate.edu/userfiles/File/faculty/s%20warren/NURhttp://www.sheltonstate.edu/userfiles/File/faculty/s%20warren/NUR

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Pacemakers and AICD ’ s Emergency Medicine Ryan Ngiam