Moderator : Dr Manju Mani

1. Cardiac implantable electronic devices (CIED) :Pacemakers,Implantable CARDIoverter defibrillators(ICD) Moderator : Dr Manju Mani www.anaesthesia.co.in anaesthesia.co.in@gmail.com

2. Brief History • First 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 1962 • First internally implanted defibrillator in 1980

3. pacemaker Device 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 function • Respond to increased metabolic demand by providing rate responsive pacing

5. Indications for Pacemaker • Aquired AV block - 30 AV block • Symptomatic bradycardia • Asystole >3 sec or escape rhythm <40bpm • Post op AV block not expected to resolve • Neuromuscular disease with AV block - 20 AV block • Permanent or intermittent symptomatic bradycardia

6. 2. After MI • Symptomatic 20 AVB or 30 AVB • Infranodal AV block with LBBB 3. Bifascicular or Trifascicular block • intermittent complete heart block with symptoms • 2 AV block • Bundle 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

8. Pacemaker Components and Anatomy

9. Pacemaker Components • Pulse Generator • Electronic Circuitry • Lead System

10. Pulse Generator • Subcutaneous or submuscular • Lithium battery • 4-10 years lifespan • long life and gradual decrease in power sudden pulse generator failure is an unlikely cause of pacemaker malfunction

11. Electronic Circuitry • Sensing circuit • Timing circuit • Output circuit

12. Bipolar Lead has both negative, (Cathode) distal and positive, (Anode) proximal electrodes Separated by 1 cm Larger diameter: more prone to fracture Compatible with ICD Unipolar Negative (Cathode) electrode in contact with heart Positive (Anode) electrode: metal casing of pulse generator Prone to oversensing Not compatible with ICD Lead System

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

15. Paced Rhythm Recognition VVI / 60

16. I II III IV V Programmable Antitachy Chamber Chamber Response Paced Sensed to Sensing Functions/Rate Function(s) Modulation Pacemaker Code DEVELOPED AS JOINT PROJECT BY NORTH AMERICAN SOCIETY OF PACING & ELECTROPHYSIOLOGY (NASPE) AND BRITISH PACING AND ELECTROPHYSIOLOGY GROUP (BPEG) - REVISED 2002 P: Simple programmable V: Ventricle V: Ventricle T: Triggered P: Pace M: Multi- programmable A: Atrium A: Atrium I: Inhibited S: Shock D: Dual (A+V) D: Dual (T+I) D: Dual (P+S) D: Dual (A+V) C: Communicating O: None O: None O: None O: None R: Rate modulating S: Single (A or V) O: None

17. Common Pacemakers • VVI • Ventricular Pacing : Ventricular sensing; intrinsic QRS Inhibits pacer discharge • VVIR • As above + has biosensor to provide Rate-responsiveness • DDD • Paces + Senses both atrium + ventricle, intrinsic cardiac activity inhibits pacer d/c, no activity: trigger d/c • DDDR • As above but adds rate responsiveness to allow for exercise

18. Rate Responsive Pacing • When the need for oxygenated blood increases, the pacemaker ensures that the heart rate increases to provide additional cardiac output Adjusting Heart Rate to Activity Normal Heart Rate Rate Responsive Pacing Fixed-Rate Pacing Daily Activities

19. Determining type of pacemaker • Wallet card: 5 letter code • CXR: code visible • Single lead in ventricle: VVI • Separate leads DDD or DVI

20. Single Chamber • VVI - lead lies in right ventricle • Independent of atrial activity • Use in AV conduction disease

21. Dual Chamber • Typically in pts with nonfibrillating atria and intact AV conduction

22. Pacemaker Interventions • Magnet application • No universal function of magnet • Model-specific magnet, some activate reed switch  asynchronous pacing at pre-set rate • Interrogation / Programming • Model-specific pacemaker programmer can non-invasively obtain data on function and reset parameters

23. Complications of Pacemaker Implantation

24. Complications of Pacemaker Implantation • Venous access • Infection • Thrombophelbitis • Pacemaker Syndrome

25. Venous Access • Bleeding • Pneumo / haemothorax • Air embolism

26. Infection • 2% for wound and ‘pocket’ infection • 1% for bacteremia with sepsis • S. aureus and S. epidermidis Rx : If bacteremic: start antibiotics, remove system, new system to be placed

27. Thrombophlebitis • Incidence 30-50% • b/c of collateralization only 0.5-3.5% devp symptoms • Swelling, pain, venous engorgement • Rx Heparin, lifetime warfarin

28. Pacemaker Syndrome • Presents with worsening of original symp post-implant of single chamber pacer - hypotension, syncope,vertigo, exercise intolerance etc • AV asynchrony retrograde VA conduction  atrial contraction against closed MV + TV  jugular venous distention + atrial dilation  sx of CHF • Rx : dual chamber pacer

29. Pacemaker syndrome

30. Pacemaker Malfunction

31. 4 broad categories • Failure to Output • Failure to Capture • Inappropriate sensing: under or over • Inappropriate pacemaker rate

32. Failure to Output absence of pacemaker spikes despite indication to pace • dead battery • fracture of pacemaker lead • disconnection of lead from pulse generator unit • Oversensing • Cross-talk: atrial output sensed by vent lead

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

35. Inappropriate sensing: Undersensing Pacemaker incorrectly misses an intrinsic deoplarization  paces despite intrinsic activity • Appearance 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 period • AMI, progressive fibrosis, lead displacement, fracture, poor contact with endocardium

36. Undersensing • Pacemaker does not “see” the intrinsic beat, and therefore does not respond appropriately Scheduled pace delivered Intrinsic beat not sensed VVI / 60

37. Inappropriate sensing: Oversensing Detection of electrical activity not of cardiac origin  inhibition of pacing activity • “underpacing” • pectoralis major: myopotentials oversensed • Electrocautery • MRI

38. VVI / 60 Oversensing • An electrical signal other than the intended P or R wave is detected ...though no activity is present Marker channel shows intrinsic activity...

39. Inappropriate Pacemaker Rate • Rare reentrant tachycardia seen w/ dual chamber pacers • Premature atrial or vent contraction  sensed by atrial lead  triggers vent contraction  retrograde VA conduction  sensed by atrial lead  triggers vent contraction  etc etc etc • Tx: Magnet application: fixed rate, terminates tachyarrthymia, • reprogram to decrease atrial sensing

40. Causes of Pacemaker Malfunction • Circuitry or power source of pulse generator • Pacemaker leads • Interface between pacing electrode and myocardium • Environmental factors interfering with normal function

41. Pulse Generator • Loose connections • Similar to lead fracture • Intermittent failure to sense or pace • Migration • Dissects along pectoral fascial plane • Failure to pace • Twiddlers syndrome • Manipulation  lead dislodgement

42. Twiddler’s Syndrome

43. Leads • Dislodgement or fracture (anytime) • Incidence 2-3% • Failure to sense or pace • Diagnosed with CXR, lead impedance • Insulation breaks • Current leaks  failure to capture • Diagnosed with measuring lead impedance (low)

44. Cardiac Perforation • Early or late • Usually well tolerated • Asymptomatic  inc’d pacing threshold, hiccups • Diagnosis : hiccups, pericardial friction rub CXR, Echo

45. Environmental Factors Interfering with Sensing • MRI • Electrocautery • Arc welding • Lithotripsy • Microwaves • Mypotentials from muscle

46. Pseudomalfunction: Hysteresis • Allows a lower rate between sensed events to occur; paced rate is higher Hysteresis Rate 50 ppm Lower Rate 70 ppm

47. Anaesthesia for insertion MAC To provide comfort To control dysrhythmias To check for proper function/capture Have external pacer & Atropine ready Continuous ECG and peripheral pulse monitoring

48. Pacemaker Insertion

49. Temporary Pacing Methods • Invasive (Direct) cardiac Pacing • Epicardial • Stainless steel Teflon coated wires. • Endocardial • Flow directed balloon electrodes • Catheter with guidewire • With PA catheter- Side port for ventricular pacing • Non Invasive (Indirect) • Transcutaneous Pacing • Combined pacing, cardioversion and defibrillation with ECG monitoring in a single unit • Instituted quickly • Safely by minimally trained person

50. Cont.. • Disadvantages of transcutaneous pacing • Inability to obtain reliable capture in • Emphysema • Pneumothorax • Morbid obesity • Difficulty with lead placement • Surgical Field • Patient position • Failure of TCP to preserve AV synchrony • For patients with poor ventricular diastolic function