Presentation on theme: "Moderator : Dr Manju Mani"— Presentation transcript:
1 Moderator : Dr Manju Mani Cardiac implantable electronic devices (CIED) : Pacemakers, Implantable CARDIoverter defibrillators (ICD)Moderator : Dr Manju Mani
2 Brief HistoryFirst totally implantable pacemaker : into the chest of 43 yr old Arne Larsson by Dr Ake Senning in Stockholm on Oct 8 ,1958.Introduction of external defibrillators in 1962First internally implanted defibrillator in 1980
3 pacemakerDevice that provides electrical stimulation to cause cardiac contraction when intrinsic cardiac electrical activity is slow or absent
4 Pacemaker Functions Stimulate cardiac depolarization Sense intrinsic cardiac functionRespond to increased metabolic demand by providing rate responsive pacing
5 Indications for Pacemaker Aquired AV block- 30 AV blockSymptomatic bradycardiaAsystole >3 sec or escape rhythm <40bpmPost op AV block not expected to resolveNeuromuscular disease with AV block- 20 AV blockPermanent or intermittent symptomatic bradycardiaClass I recommendations From Rosen
6 2. After MISymptomatic 20 AVB or 30 AVBInfranodal AV block with LBBB3. Bifascicular or Trifascicular blockintermittent complete heart block with symptoms2 AV blockBundle branch block
7 4. Sinus Node Dysfunction - with symptoms as a result of long term drug therapy - symptomatic chronotropic incompetence 5 . Hypertensive carotid sinus & neurocardiac symptoms - recurrent syncope associated with carotid sinus stimulation - Asystole of > 3 sec duration in absense of any medication
12 Lead SystemBipolarLead has both negative, (Cathode) distal and positive, (Anode) proximal electrodesSeparated by 1 cmLarger diameter: more prone to fractureCompatible with ICDUnipolarNegative (Cathode) electrode in contact with heartPositive (Anode) electrode: metal casing of pulse generatorProne to oversensingNot compatible with ICDBoth are ONE wire. Don’t confuse bipolar and unipolar leads with single chamber and dual chamber pacemakers.Unipolar prone to oversensing because Anode may pick up myopotenials from muscle or other extrinsic source
13 Bipolar + - current travels only a short distance between electrodes small pacing spike: <5mm+Anode-Cathode
14 Unipolar + - current travels a longer distance between electrodes larger pacing spike: >20mm+Anode-Cathode
16 Pacemaker Code DEVELOPED AS JOINT PROJECT BY NORTH AMERICAN SOCIETY OF PACING & ELECTROPHYSIOLOGY (NASPE) AND BRITISH PACING AND ELECTROPHYSIOLOGY GROUP (BPEG) REVISED 2002IChamberPacedIISensedIIIResponseto SensingIVProgrammableFunctions/RateModulationVAntitachyFunction(s)P: SimpleprogrammableV: VentricleV: VentricleT: TriggeredP: PaceM: Multi-programmableA: AtriumA: AtriumI: InhibitedS: ShockD: Dual (A+V)D: Dual (A+V)D: Dual (T+I)C: CommunicatingD: Dual (P+S)The first letter refers to the chamber(s) being pacedThe second letter refers to the chamber(s) being sensedThe third letter refers to the pacemaker’s response to a sensed event:T = Triggered D = Dual (inhibited and triggered*)I = Inhibited O = No response*In a single chamber mode, “triggered” means that when an intrinsic event is sensed, a pace is triggered immediately thereafter. In a dual chamber mode, “triggered” means that a sensed atrial event will initiate (trigger) an A-V delay.The fourth letter denotes the pacemaker’s programmability and whether it is capable of rate response:P = Simple Programmable (rate and/or output)M = Multiprogrammable (rate, output, sensitivity, etc.)C = Communicating (pacemaker can send/receive information to/from the programmer)R = Rate ModulationO = NoneNote that this sequence is hierarchical. In other words, it is assumed that if a pacemaker has rate modulation capabilities, “R”, that it also can communicate, “C”.The fifth letter represents the pacemaker’s antitachycardia functions:P = Pace D = Dual (pace and shock available)S = Shock O = NoneYou may want to test the audience by having them describe different pacing modes. More modes and ECG strips are found in Module 2.O: NoneO: NoneO: NoneR: Rate modulatingO: NoneS: Single(A or V)O: None
17 Common PacemakersVVIVentricular Pacing : Ventricular sensing; intrinsic QRS Inhibits pacer dischargeVVIRAs above + has biosensor to provide Rate- responsivenessDDDPaces + Senses both atrium + ventricle, intrinsic cardiac activity inhibits pacer d/c, no activity: trigger d/cDDDRAs above but adds rate responsiveness to allow for exerciseBiosensors --- most are vibrations sensors that increase HR in proportion to activity sensed, but can also have pH, venous temp, resp rate, QT interval, stroke volume, O2 sat, RA pressure sensors less commonly.Dual chamber pacing allows for atrial contribution to CO (up to 30% of CO)
18 Rate Responsive Pacing When the need for oxygenated blood increases, the pacemaker ensures that the heart rate increases to provide additional cardiac outputAdjusting Heart Rate to ActivityNormal Heart RateRate Responsive PacingFixed-Rate PacingPiezoelectric crystal that detects mechanical signals produced by movement, mechanical signals translate into electrical signals that increase rate of the pacemakerDaily Activities
19 Determining type of pacemaker Wallet card: 5 letter codeCXR: code visibleSingle lead in ventricle: VVISeparate leads DDD or DVI
20 Single Chamber VVI - lead lies in right ventricle Independent of atrial activityUse in AV conduction disease
21 Dual ChamberTypically in pts with nonfibrillating atria and intact AV conduction
22 Pacemaker Interventions Magnet applicationNo universal function of magnetModel-specific magnet, some activate reed switch asynchronous pacing at pre-set rateInterrogation / ProgrammingModel-specific pacemaker programmer can non- invasively obtain data on function and reset parametersMagnet applicationUseful to test pacemaker function and battery life, especially if intrinsic HR > paced ratePre-set paced rate dec’s w/ dec’g battery lifeProgrammable functions include lower rate limit, upper rate limit, AV interval, energy output, refractory periods, blanking period (interval after d/c during which no signals are sensed), mode of function (e.g. A, V, or D), max atrial tracking rate (fastest atrial rate pacer will keep up with), vent pacing response, algorithm for tachycardia termination, sensing parameters
26 Infection 2% for wound and ‘pocket’ infection 1% for bacteremia with sepsisS. aureus and S. epidermidisRx :If bacteremic: start antibiotics, remove system, new system to be placed
27 Thrombophlebitis Incidence 30-50% b/c of collateralization only % devp symptomsSwelling, pain, venous engorgementRxHeparin, lifetime warfarin
28 Pacemaker SyndromePresents with worsening of original symp post-implant of single chamber pacer- hypotension, syncope,vertigo, exercise intolerance etcAV asynchrony retrograde VA conduction atrial contraction against closed MV + TV jugular venous distention + atrial dilation sx of CHFRx : dual chamber pacerPresent w/ presyncope, syncope, orthostatic dizziness, lightheadedness, fatigue, lethargy, CP, neck fullness, other non-specific complaintsCan get w/ dual chamber pacer if SA node rate > paced rate in pts w/ AV block
29 Figure A 12-lead ECG from a 63-year-old woman with recurrent syncope several months after implantation of a VVI pacemaker. The arrows show the retrograde P waves of 1:1 ventricular-to-atrial conduction that may be associated with a pacemaker syndrome.Pacemaker syndrome
31 4 broad categories Failure to Output Failure to Capture Inappropriate sensing: under or overInappropriate pacemaker rate
32 Failure to Outputabsence of pacemaker spikes despite indication to pacedead batteryfracture of pacemaker leaddisconnection of lead from pulse generator unitOversensingCross-talk: atrial output sensed by vent leadCross-talk = oversensing of pacemaker generated electrical activity E.g. vent lead senses atrial pacing spike misinterprets as vent contraction inhibits pacer d/c skipped beat dizziness / syncope
33 Failure to capture spikes not followed by a stimulus-induced complex change in endocardium: ischemia, infarction, hyperkalemia, class III antiarrhythmics (amiodarone, bertylium)
34 Failure to sense or capture in VVI Figure A 12-lead ECG with a lead-V1 rhythm strip from an 84-year-old man who returned to a pacemaker clinic with dizziness 11 years after implantation of a VVI pacemaker. Arrows show pacing artifacts continuing regularly (68/min) not sensing for the patient's intrinsic beats and not producing paced beats. The asterisks indicate the single incidence of ventricular capture by the pacemakerFailure to sense or capture in VVI
35 Inappropriate sensing: Undersensing Pacemaker incorrectly misses an intrinsic deoplarization paces despite intrinsic activityAppearance of pacemaker spikes occurring earlier than the programmed rate: “overpacing”may or may not be followed by paced complex: depends on timing with respect to refractory periodAMI, progressive fibrosis, lead displacement, fracture, poor contact with endocardium
36 Scheduled pace delivered Intrinsic beat not sensed UndersensingPacemaker does not “see” the intrinsic beat, and therefore does not respond appropriatelyScheduled pace deliveredIntrinsic beat not sensedVVI / 60
37 Inappropriate sensing: Oversensing Detection of electrical activity not of cardiac origin inhibition of pacing activity“underpacing”pectoralis major: myopotentials oversensedElectrocauteryMRI
38 OversensingVVI / 60...though no activity is presentMarker channel shows intrinsic activity...An electrical signal other than the intended P or R wave is detectedOversensing will exhibit pauses in single chamber systems. In dual chamber systems, atrial oversensing may cause fast ventricular pacing without P waves preceding the paced ventricular events.
39 Inappropriate Pacemaker Rate Rare reentrant tachycardia seen w/ dual chamber pacersPremature atrial or vent contraction sensed by atrial lead triggers vent contraction retrograde VA conduction sensed by atrial lead triggers vent contraction etc etc etcTx: Magnet application: fixed rate, terminates tachyarrthymia,reprogram to decrease atrial sensing
40 Causes of Pacemaker Malfunction Circuitry or power source of pulse generatorPacemaker leadsInterface between pacing electrode and myocardiumEnvironmental factors interfering with normal function
41 Pulse Generator Loose connections Migration Twiddlers syndrome Similar to lead fractureIntermittent failure to sense or paceMigrationDissects along pectoral fascial planeFailure to paceTwiddlers syndromeManipulation lead dislodgement
43 Leads Dislodgement or fracture (anytime) Insulation breaks Incidence 2-3%Failure to sense or paceDiagnosed with CXR, lead impedanceInsulation breaksCurrent leaks failure to captureDiagnosed with measuring lead impedance (low)Fractures occur at sharp turns (pulse generator, entry into vein, in ventricle, most commonly occurring at the clavicle/first rib locationMeasure lead impedance w/ pacemaker programmerInsulation break like leaky garden hose
44 Cardiac Perforation Early or late Usually well tolerated Asymptomatic inc’d pacing threshold, hiccupsDiagnosis : hiccups, pericardial friction rubCXR, Echo
45 Environmental Factors Interfering with Sensing MRIElectrocauteryArc weldingLithotripsyMicrowavesMypotentials from muscle
46 Pseudomalfunction: Hysteresis CorePace Module 4: TroubleshootingPseudomalfunction: HysteresisAllows a lower rate between sensed events to occur; paced rate is higherHysteresis Rate 50 ppmLower Rate 70 ppmHysteresis provides the capability to maintain the patient’s intrinsic heart rhythm as long as possible, while providing back-up pacing if the intrinsic rhythm falls below the hysteresis rate. Because hysteresis exhibits longer intervals between sensed events, it may be perceived as oversensing.
47 Anaesthesia for insertion MACTo provide comfortTo control dysrhythmiasTo check for proper function/captureHave external pacer & Atropine readyContinuous ECG and peripheral pulse monitoring
49 Temporary Pacing Methods Invasive (Direct) cardiac PacingEpicardialStainless steel Teflon coated wires.EndocardialFlow directed balloon electrodesCatheter with guidewireWith PA catheter- Side port for ventricular pacingNon Invasive (Indirect)Transcutaneous PacingCombined pacing, cardioversion and defibrillation with ECG monitoring in a single unitInstituted quicklySafely by minimally trained person
50 Cont.. Disadvantages of transcutaneous pacing Inability to obtain reliable capture inEmphysemaPneumothoraxMorbid obesityDifficulty with lead placementSurgical FieldPatient positionFailure of TCP to preserve AV synchronyFor patients with poor ventricular diastolic function
51 Transesophageal pacing UsesNoninvasive electrophysiological studiesTermination of reentrant tachydysrhythmiasTemporary bradycardia pacingDisadvantagesNot suitable for ventricular pacingIntact AV conduction is required
53 Automated Implantable Cardioverter Defibrillator (aicd) IndicationsRecurrent VT/VFNot responding to medical therapyPoor risk for surgical ablation2/3rd patients still require medical therapyHigh costSurvival rate is similar
54 Settings Gives a shock at 0.1-30 joules Usually 25 joules Takes 5-20 seconds to sense VT/VFTakes 5-15 seconds more to chargesecond delay before next shock is administeredTotal of 5 shocks, then pausesIf patient is touched, may feel a buzz or tingleIf CPR is needed, wear rubber gloves for insulation
59 Generic defibrillator Code DEVELOPED AS JOINT PROJECTS BY NORTH AMERICAN SOCIETY OF PACING & ELECTROPHYSIOLOGY (NASPE) AND BRITISH PACING AND ELECTROPHYSIOLOGY GROUP (BPEG) REVISED 2002Position 1Shock chambersPosition 2Anti tachycardia pacing chambersPosition 3Tachycardia detectionPosition 4Anti bradycardia pacing chambersO = noneE = electrocardiogramA = atriumH = haemodynamicV = VentricleV = ventricleD = dual (A+ V)D = dual (A + V)
60 Surgical techniques Non thoracotomy (More common) Fluoroscopically TransvenousMonitored anesthesia care.General anesthesia- if repeated induction of arrhythmia.Thoracotomy ( For Pediatric patients- epicardial leads)Median sternotomyLeft thoracotomySubxiphoid approachSubcostal approach
61 Anesthesia MAC vs General Lead is placed in heart Usually general due to induction of VT/VF so AICD can be checked for performanceLead is placed in heartGenerator is placed generally in upper chest
62 ASA PRACTICE ADVISORY FOR PERI OPERATIVE MANAGEMENT OF PATIENTS WITH CARDIAC IMPLANTABLE ELECTRONIC DEVICES
63 PRE OPERATIVE EVALUATION A. Establish whether a patient has a cardiac rhythm management device (CIED). 1. Conduct a focused history (patient interview, medical records review, and review of available chest x-rays, electrocardiograms, or any available monitor or rhythm strip information). 2. Conduct a focused physical examination (check for scars and palpate for device).
64 3. Define the type of CIED. a 3. Define the type of CIED. a. Obtain manufacturer’s identification card from patient or other source. b. Order chest x-ray if no other data are available.
65 B. Determine the dependence on pacing function of the CIED. 1. Patient has history of symptomatic bradyarrhythmia resulting in CIED implantation.2. Patient has history of successful atrioventricular nodal ablation.3. Patient has inadequate escape rhythm at lowest programmable pacing rate.
66 C. Determine CIED function. 1 C. Determine CIED function. 1. Interrogate device (consultation with a cardiologist or pacemaker-ICD service may be necessary). 2. Determine whether the device will capture when it paces (i.e., produce a mechanical systole with a pacemaker impulse).
67 Pre operative preperation Determine whether EMI (electromagnetic interference) is likely to occur during the planned procedure.The pacemeker senses cautery signal as electrical activity, & may be inhibited causing asystole.In case of ICD, it may sense cautery as ventricular fibrillation and deliver a shock.
68 Determine whether reprogramming pacing function to asynchronous mode or disabling rate responsive function is advantageous.2. Suspend antitachyarrhythmia functions if present.3. consider use of a bipolar electrocautery system or ultrasonic (harmonic) scalpel.4. Temporary pacing and defibrillation equipment should be immediately available
69 Intra operative management Monitor operation of the CIED. 1. Conduct electrocardiographic monitoring per ASA standard. 2. Monitor peripheral pulse (e.g., manual pulse palpation, pulse oximeter plethysmogram, and arterial line). 3. Pacemaker is not an indication for insertion of pulmonary artery & central venous catheter.
70 Induction & maintenance Narcotics & inhalational agents can be used successfully.Succinylcholine fasciculations can inhibit stimulation and hence should be avoided.Etomidate & ketamine should be avoided : cause myoclonic movementsCases of pacemeker dislodgement by IPPVNitrous oxide entrapment in pacemeker pocket.
72 electrocautery1.Assure that electrosurgical receiving plate is positioned so the current pathway does not pass through or near the CIED system. It placed on a site different from the thigh (e.g., the superior posterior aspect of the shoulder contralateral to the generator position for a head and neck case). 2. Avoid proximity of the cautery’s electrical field to the pulse generator or leads.
73 3. use short, intermittent and irregular bursts at the lowest feasible energy levels. 4. consider the use of a bipolar electrocautery system or ultrasonic (harmonic) scalpel in place of a monopolar electrocautery system if possible
74 Radiofrequency ablation Avoid direct contact between the ablation catheter and the pulse generator and leads.2. keep the RF’s current path as far away from the pulse generator and lead system as possible.
75 lithotripsy1. Avoid focusing the lithotripsy beam near the pulse generator. 2. If the lithotripsy system triggers on the R- wave, consider preoperative disabling of atrial pacing.
76 Magnetic resonance imaging 1. MRI is generally contraindicated in patients with CIEDs. 2. If an MRI must be performed, consult with the ordering physician, the patient’s cardiologist, the diagnostic radiologist, and the CIED manufacturer.
77 Radiation therapyRadiation therapy can be safely performed in patients who have CIEDs.2. Surgically relocate the CIED if the device will be in the field of radiation.
78 Emergency defibrillation or cardioversion A . terminate all sources of EMI while the magnet is removed. b. Remove the magnet to reenable antitachycardia therapies. c. If the above activities fail to restore ICD function, proceed with emergency external defibrillation or cardioversion.
79 For external defibrillation a. Position defibrillation/cardioversion pads or paddles as far as possible from the pulse generator. b. Position defibrillation/cardioversion pads or paddles perpendicular to the major axis of the CIED to the extent possible by placing them in an anterior-posterior location.
80 c. If it is technically impossible to place the pads or paddles in locations that help to protect the CIED, then defibrillate/cardiovert the patient in the quickest possible way and be prepared to provide pacing through other routes.
81 Post operative management A. Continuously monitor cardiac rate and rhythm and have back-up pacing and defibrillation equipment immediately available throughout the immediate postoperative period.
82 B. Interrogate and restore CIED function in the immediate postoperative period. 1. Interrogate CIED; consultation with a cardiologist or pacemaker-ICD service may be necessary.2. Restore all antitachyarrhythmic therapies in ICDs.3. Assure that all other settings of the CIED are appropriate