Pacemakers and ICD ’ s Dr.Gharibzadeh Alaleh Rashidnasab.

PacemakersPacemakersandand

ICDICD’’ss

Dr.GharibzadehDr.Gharibzadeh

Alaleh RashidnasabAlaleh Rashidnasab

SCD most common cause of death SCD most common cause of death

Sudden Cardiac DeathSudden Cardiac Death

Sudden Cardiac DeathSudden Cardiac Death

Death by an arrhythmia:Death by an arrhythmia:

BradycardiaBradycardia

TachycardiaTachycardia

Atrial FibrillationAtrial Fibrillation

Ventricular FibrillationVentricular Fibrillation

BradycardiaBradycardia

Sinus node discharges at a rate < 60 bpmSinus node discharges at a rate < 60 bpm

Decreased CO may occur Decreased CO may occur

TachycardiaTachycardia

Discharge rate from the sinus node is Discharge rate from the sinus node is increased and is > 100 bpmincreased and is > 100 bpm

Increased myocardial oxygen consumption Increased myocardial oxygen consumption is associated with increased HRis associated with increased HR

Atrial FibrillationAtrial Fibrillation

Total disorganization of atrial activity without effective Total disorganization of atrial activity without effective atrial contractionatrial contraction

Can often result in decrease in CO because of Can often result in decrease in CO because of ineffective atrial contractions and rapid ventricular ineffective atrial contractions and rapid ventricular responseresponse

Goals are decreased in ventricular response and Goals are decreased in ventricular response and conversion to sinus rhythmconversion to sinus rhythm

Ventricular FibrillationVentricular Fibrillation

Severe derangement of the heart rhythm Severe derangement of the heart rhythm characterized on ECG by irregular undulations of characterized on ECG by irregular undulations of varying contour and amplitudevarying contour and amplitude

No effective contraction or CO occursNo effective contraction or CO occurs

If untreated, patient will dieIf untreated, patient will die

TreatmentsTreatments

Drug therapyDrug therapy

DefibrillatorsDefibrillators

PacemakersPacemakers

ICDsICDs(Implantable Cardioverter Defibrillator):(Implantable Cardioverter Defibrillator):

ICD Therapy consists of pacing, cardioversion, and ICD Therapy consists of pacing, cardioversion, and defibrillation therapies to treat brady and tachy defibrillation therapies to treat brady and tachy arrhythmiasarrhythmias

Historical PerspectiveHistorical Perspective

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

galvanometergalvanometer

1958 1958 –– Senning and Elmqvist 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 1960 –– First atrial triggered pacemaker First atrial triggered pacemaker

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

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

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


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

1994 1994 –– Cardiac resynchronization pacing Cardiac resynchronization pacing

1998 1998 –– Automatic capture detection Automatic capture detection

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

19801980Large devices -Large devices -Abdominal siteAbdominal site

First human implantsFirst human implants

Thoracotomy, multiple incisionsThoracotomy, multiple incisions

Primary implanter= cardiac surgeonPrimary implanter= cardiac surgeon

General anesthesiaGeneral anesthesia

Long hospital staysLong hospital stays

Complications from major surgeryComplications from major surgery

Perioperative mortality up to 9%Perioperative mortality up to 9%

Nonprogrammable therapyNonprogrammable therapy

High-energy shock onlyHigh-energy shock only

Device longevity Device longevity 1.5 years 1.5 years

Fewer than 1,000 implants/yearFewer than 1,000 implants/year

TodayTodaySmall devices - Small devices -

Pectoral sitePectoral site

First-line therapy for VT/VF patientsFirst-line therapy for VT/VF patients Treatment of atrial arrhythmiasTreatment of atrial arrhythmias Cardiac resynchronization therapy for HFCardiac resynchronization therapy for HF Transvenous, single incisionTransvenous, single incision Local anesthesia; conscious sedationLocal anesthesia; conscious sedation Short hospital stays and few complicationsShort hospital stays and few complications Perioperative mortality < 1%Perioperative mortality < 1% Programmable therapy optionsProgrammable therapy options Single- or dual-chamber therapySingle- or dual-chamber therapy Battery longevity up to 9 yearsBattery longevity up to 9 years More than 100,000 implants/yearMore than 100,000 implants/year

Evolution of ICD Therapy: Evolution of ICD Therapy:

Pacemaker BasicsPacemaker Basics

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

Sense intrinsic cardiac Sense intrinsic cardiac electric potentialselectric potentials

A Brief History of PacemakersA Brief History of Pacemakers

ICD BasicsICD BasicsDesigned to treat a cardiac tachydysrythmiaDesigned to treat a cardiac tachydysrythmiaAn external programmer is used to monitor and An external programmer is used to monitor and access the device parameters and therapies for each access the device parameters and therapies for each patient.patient.

Performs cardioversion/defibrillationPerforms cardioversion/defibrillation Ventricular rate exceeds programmed cut-off rateVentricular rate exceeds programmed cut-off rateATP (antitachycardia pacing)ATP (antitachycardia pacing) Overdrive pacing in an attempt to terminate Overdrive pacing in an attempt to terminate

ventricular tachycardiasventricular tachycardiasSome have pacemaker function (combo devices)Some have pacemaker function (combo devices)

209 cc 120 cc 80 cc 80 cc 72 cc 54 cc

62 cc 49 cc 39.5 cc 39.5 cc 36 cc38 cc39.5 cc

Implantable Defibrillators (1989-2003)

Pacemaker and ICD BasicsPacemaker and ICD Basics

Pulse GeneratorsPulse Generators Placed submuscularlyPlaced 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


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 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

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

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

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-talkcross-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

ICD ComplicationsICD Complications

Similar to pacemaker complicationsSimilar to pacemaker complications Sensing and pacing failuresSensing and pacing failures Inappropriate cardioversionInappropriate cardioversion Ineffective cardioversion/defibrillationIneffective cardioversion/defibrillation

ICD Sensing failuresICD Sensing failures

Similar to pacmakersSimilar to pacmakers OversensingOversensing UndersensingUndersensing

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 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 ptIf pt’’s internal defibrillator activates during chest 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 Lead fractureLead fracture Insulation breakageInsulation breakage

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

Future ICD TechnologyFuture ICD Technology

Enhanced automaticityEnhanced automaticity:: Device software that suggests programming options Device software that suggests programming options

to the clinician based on the patient’s history and to the clinician based on the patient’s history and demographicsdemographics

Continued reductions in device sizeContinued reductions in device size:: Will require advancements in battery, capacitor and Will require advancements in battery, capacitor and

circuitry technology and/or decreasing the delivered circuitry technology and/or decreasing the delivered energy output.energy output.

Future ICD TechnologyFuture ICD Technology

Enhanced diagnostics:Enhanced diagnostics: Monitoring of the progression of both arrhythmias and Monitoring of the progression of both arrhythmias and

concomitant cardiac conditionsconcomitant cardiac conditions

Enhanced lead technology:Enhanced lead technology: Thinner leads with increased diagnostic capabilities, Thinner leads with increased diagnostic capabilities,

e.g., pressure sensing.e.g., pressure sensing.

Patient follow-up modifications:Patient follow-up modifications: Broadly available programmer technology that Broadly available programmer technology that

enables remote transfer of data, reducing the need for enables remote transfer of data, reducing the need for in-clinic visits. in-clinic visits.

Thank youThank you

Pacemakers and ICD ’ s Dr.Gharibzadeh Alaleh Rashidnasab.

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