1. Moderator : Dr Manju Mani
Cardiac implantable electronic devices (CIED) : Pacemakers, Implantable CARDIoverter defibrillators (ICD)
Moderator : Dr Manju Mani

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
Class I recommendations From Rosen

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. Lead System
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
Both 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

15. Paced Rhythm Recognition
VVI / 60

16. Pacemaker Code DEVELOPED AS JOINT PROJECT BY NORTH AMERICAN SOCIETY OF PACING & ELECTROPHYSIOLOGY (NASPE) AND BRITISH PACING AND ELECTROPHYSIOLOGY GROUP (BPEG) REVISED 2002 I
Chamber
Paced II
Sensed
III
Response
to Sensing IV
Programmable
Functions/Rate
Modulation V
Antitachy
Function(s)
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 (A+V)
D: Dual (T+I)
C: Communicating
D: Dual (P+S)
The first letter refers to the chamber(s) being paced
The second letter refers to the chamber(s) being sensed
The 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 Modulation
O = None
Note 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 = None
You may want to test the audience by having them describe different pacing modes. More modes and ECG strips are found in Module 2.
O: None
O: None
O: None
R: Rate modulating
O: None
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
Biosensors --- 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 output
Adjusting Heart Rate to Activity
Normal Heart Rate
Rate Responsive Pacing
Fixed-Rate Pacing
Piezoelectric crystal that detects mechanical signals produced by movement, mechanical signals translate into electrical signals that increase rate of the pacemaker
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
Magnet application
Useful to test pacemaker function and battery life, especially if intrinsic HR > paced rate
Pre-set paced rate dec’s w/ dec’g battery life
Programmable 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

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 % 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
Present w/ presyncope, syncope, orthostatic dizziness, lightheadedness, fatigue, lethargy, CP, neck fullness, other non-specific complaints
Can 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

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
Cross-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 pacemaker
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. Scheduled pace delivered Intrinsic beat not sensed
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. Oversensing
VVI / 60
...though no activity is present
Marker channel shows intrinsic activity...
An electrical signal other than the intended P or R wave is detected
Oversensing 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 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 Migration Twiddlers syndrome
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) Insulation breaks
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)
Fractures occur at sharp turns (pulse generator, entry into vein, in ventricle, most commonly occurring at the clavicle/first rib location
Measure lead impedance w/ pacemaker programmer
Insulation break like leaky garden hose

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
CorePace Module 4: Troubleshooting
Pseudomalfunction: Hysteresis
Allows a lower rate between sensed events to occur; paced rate is higher
Hysteresis Rate 50 ppm
Lower Rate 70 ppm
Hysteresis 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
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

51. Transesophageal pacing
Uses
Noninvasive electrophysiological studies
Termination of reentrant tachydysrhythmias
Temporary bradycardia pacing
Disadvantages
Not suitable for ventricular pacing
Intact AV conduction is required

52. Implantable Cardioverter Defibrillators

53. Automated Implantable Cardioverter Defibrillator (aicd)
Indications
Recurrent VT/VF
Not responding to medical therapy
Poor risk for surgical ablation
2/3rd patients still require medical therapy
High cost
Survival rate is similar

54. Settings Gives a shock at 0.1-30 joules Usually 25 joules
Takes 5-20 seconds to sense VT/VF
Takes 5-15 seconds more to charge
second delay before next shock is administered
Total of 5 shocks, then pauses
If patient is touched, may feel a buzz or tingle
If CPR is needed, wear rubber gloves for insulation

55. AICD in situ

56. ICD

57. Implantable Defibrillators (1989-2003)
120 cc
209 cc
80 cc
80 cc
72 cc
54 cc
62 cc
49 cc
39.5 cc
39.5 cc
36 cc
39.5 cc
38 cc
PG assembly 2010

58. PG assembly 2010

59. Generic defibrillator Code DEVELOPED AS JOINT PROJECTS BY NORTH AMERICAN SOCIETY OF PACING & ELECTROPHYSIOLOGY (NASPE) AND BRITISH PACING AND ELECTROPHYSIOLOGY GROUP (BPEG) REVISED 2002
Position 1
Shock chambers
Position 2
Anti tachycardia pacing chambers
Position 3
Tachycardia detection
Position 4
Anti bradycardia pacing chambers
O = none
E = electrocardiogram
A = atrium
H = haemodynamic
V = Ventricle
V = ventricle
D = dual (A+ V)
D = dual (A + V)

60. Surgical techniques Non thoracotomy (More common) Fluoroscopically
Transvenous
Monitored anesthesia care.
General anesthesia- if repeated induction of arrhythmia.
Thoracotomy ( For Pediatric patients- epicardial leads)
Median sternotomy
Left thoracotomy
Subxiphoid approach
Subcostal 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 performance
Lead is placed in heart
Generator 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 movements
Cases of pacemeker dislodgement by IPPV
Nitrous oxide entrapment in pacemeker pocket.

71. Factors that increase pacing threshold:
Acidosis / alkalosis
Hypothermia
Hyperkalemia
Hypoglycemia
Severe hypoxia
Hypothyroidism
Myocardial ischemia/ infarction

72. electrocautery
1.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. lithotripsy
1. 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 therapy
Radiation 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

83. Thank You