Patients with pacemaker anaesthetic implications

1. Speaker -Dr Gowri shankar B
chair person – Dr Ashwini H R

2.  Basics of CIEDS functions “Cardiac Implanted
Electronic Devices”
 Indications for their use.
 Anaesthetic management
◦ Preoperative
◦ Intraoperative
◦ Postoperative
 Special situations

3. A Pacemaker is a device capable of generating artificial
pacing impulses and delivering them to the heart
Consists of a pulse generator, lead and appropriate
electrodes

4.  1958 : 1st battery operated pacemaker
 1969: AV sequential pacing
 1980: 1st AICD
 1985: AICD was approved by FDA
 1988: rate modulation

8. Pacemakers are evolving fast ..!

9. Pacemakers are evolving fast..!
2013

10.  Pulse Generator: It includes the
energy source (battery) and electric
circuits for pacing and sensory
function
 Leads: Insulated wires connecting
pulse generator and electrodes
 Electrode: An exposed metal end of
the lead in contact with the
endocardium or epicardium

11. Pacemaker leads as seen on fluroscopy
(Dual chamber system)
Atrial lead
Ventricular leads

12.  Unipolar Pacing: Current flows from the
cathode, stimulates the heart and
returns to anode on the casing of pulse
generator via the myocardium and
adjacent tissue to complete the circuit
 Bipolar Leads: Two separate electrodes,
anode (positive pole) and cathode
(negative pole), both located close to
each other within the chamber that is
being paced

13.  Pacing Threshold: minimum amount of energy
required to consistently cause depolarization and
contraction of the heart
 Sensitivity: The minimal voltage level of the patient’s
intrinsic R wave or P wave that must be exceeded for
the pacemaker to sense and activate the sensing
circuit of the pulse generator, resulting in inhibition
or triggering of the pacing circuit.

14.  Resistance: The impedance to the flow of current.
Abrupt changes in the impedance may indicate
problem with the lead system
 Pulse duration is the time in milliseconds between
the initiation and termination of the current flow
originating from the pacemaker
 Pulse amplitude is the height of the pacemaker
spike in millivolts

15.  Escape interval is the number of milliseconds
between the patient's own R wave and the next
paced beat
 Automatic interval is the number of milliseconds
between two pacing spikes
 Hysteresis is particularly useful in patients with sick
sinus syndrome. Hysteresis is the difference between
the escape and automatic intervals

18. Code Paced sensed Response Indication
example
AOO Atrium None None Sick sinus
syndrome
VOO Ventricle None None Complete HB
VVI Ventricle Ventricle Inhibited AF
DDD Both Both Inhibited AV + SA
disease
DDI Both Both Inhibited AV + SA
disease

21.  AICD system consists of a pulse generator and leads for
tachyarrhythmia detection and therapy
 Provides antitachycardia and antibradycardia pacing,
synchronized or nonsynchronized shocks, telemetry
and diagnostics including storing even electrograms
and history logs
 Modern ICD use transvenous lead systems for sensing,
pacing and shocks

23.  Cardiac arrest due to VT/VF which is not due to a
transient or reversible cause
 Spontaneous sustained VT
 Syncope with hemodynamically significant sustained
VT or VF
 NSVT with CAD, previous MI, LV dysfunction and
inducible VF or VT not suppressed by a class 1
antidysrhythmic

25.  Measures each R-R interval
 Categorize the rate (normal, too fast or too slow) If
sufficient number of short R-R interval within in a
period of time- will declare tachycardia episode
 Takes 5-20 seconds to sense VT/VF, another 5-15
seconds to charge. Delay 2.5-10 seconds before next
shock is administered. Total 5 shocks in a episode then
pauses

27.  Asynchronous pacing without rate responsiveness
 No apparent rhythm or rate change
 Continuous or transient loss of pacing
 Pacer enters diagnostic “Threshold Test Mode”
 Magnet mode disabled permanently by
programming or temporarily suspended

28.  Radio wave frequency between 0 -10 9 Hz and
microwaves frequency 109 – 10 11 Hz cause EMI
 Frequencies 5 -100 Hz overlap with intracardiac
signals
 Shielding of pulse generator, bipolar leads, and
filtering of incoming signals offers some protection
against EMI

29.  Asynchronous pacing
 Pacemaker inhibition or triggering
 Resetting or reprogramming pacemaker
 Damage to electronic circuits
 Burn injury to myocardium
 Inappropriate activation of rate adaptive feature
and anti tachycardia therapy

31. Anaesthetic management
Preoperative
Assessment
History Examination Investigations
Preparation
Intraoperative
Monitoring Conduct
Regional General
Postoperative

32. Anaesthetic management
Preoperative
Assessment
History Examination Investigations
Preparation
intraoperative
monitoring conduct
Regional General
postoperative

33. • Establish whether a patient has a CIED
o Conduct a focused history
o Conduct a focused physical examination
• Define the type of CIED
o Obtain manufacturer’s identification card from patient or
other source.
o Order chest x-ray studies if no other data are available.
o Refer to supplemental resources (e.g., manufacturer’s
databases).

34. • Determine dependency on pacing function of the
CIED
o History of symptomatic bradyarrhythmia resulting in CIED
implantation
o History of successful atrioventricular nodal ablation
• Determine CIED function
o Interrogate device
o Determine whether the device will capture when it paces
o Consider contacting the manufacturer for perioperative
recommendations

36. Pocket complications
Pocket hematoma
Infection
Erosion
Wound pain
Allergic reactions
Pacemaker complications
Lead dislodgement
Pneumothorax /air embolism
Cardiac perforation
Extracardiac stimulation
Venous thrombosis
Coronary sinus dissection
Twidller syndrome
Pacemaker malfunction

37.  Routine biochemical and hematological
investigation, coagulation screening
 Serum electrolyte measurement(specially k+ level)
 Well penetrated chest X-ray- model number of
pacemaker (radio opaque marker), integrity and
position of leads
 Baseline 12-lead ECG-
◦ No or intermittent pacing spike- own rhythm
◦ Pacing spike before every beat- pacemeker dependent

38.  Continue antiarrythmic drug and other cardiac drugs
as mandated
 Determine whether EMI is likely to occur during the
planned procedure
 Determine whether reprogramming pacing function
to asynchronous mode or disabling rate responsive
function is advantageous
 Temporary pacing and defibrillation equipment
should be immediately available

39.  Pacemaker dependent patients
 Major procedure in abdomen and chest
 Rate adaptive feature of pacemakers
 Suspension of antitachycardia function
 Surgical procedures with high chances
of EMI

40. Anaesthetic management
Preoperative
Assessment
History Examination Investigations
Preparation
Intraoperative
Monitoring Conduct
Regional General
Postoperative

41. Anaesthetic management
Preoperative
Assessment
History Examination Investigations
Preparation
Intraoperative
Monitoring Conduct
Regional General
Postoperative

42.  Monitoring
 Anesthetic technique
 Measures to prevent device malfunctioning
 Pacemaker failure trouble shooting
 Preparation for temporary pacemaker and
defibrillation

43.  ECG monitoring of a patient must include the
ability to detect pacing discharges. Artifact filtering
must be disabled so that the monitor will “paint”
pacing spikes onto the display
 Signs of peripheral perfusion-pulseoximetry or
arterial pressure waveform display
 Invasive monitoring –PAC, CVP- can dislodge when
less than 4 wks old

44. Regional-
 No guideline favoring or contradicting.
 Paced heart cannot compensate hypotension by
tachycardia- used cautiously
 case of pacemaker interference caused by activation of a
nerve stimulator has been reported

45. General anaesthesia
 Both narcotics and inhalational are safe
 Avoid using nitrous oxide, especially if CIED is reccently
inserted.
 Etomidate , ketamine should avoided
 Avoid shivering due to perioperative hypothermia
 Succinylcholine should avoided
 Non-depolarising muscle relaxant is safe

46. According to FDA 255 of 456 adverse events are due to
electro-cautery
The responses of pacemakers to electrocautery include:
 Inhibition of pacing
 Asynchronous pacing
 Reset to backup mode
 Myocardial burns (rare)
 VF (rare).

47.  Unipolar vs Bipolar vs Ultrasonic scalpel
 Distance to pulse generator
 Unipolar return pad
 Lowest energy possible in short bursts

48.  Generator failure: rare in a device that has previously been
evaluated and not near the end of useful battery life, unless
the generator (or leads) is struck directly by the ESU
 Lead failure :can result in undersensing , oversensing , or
failure to deliver sufficient energy to the myocardium to
produce depolarization
 Failure of capture: Myocardial changes that lengthen the
refractory period or increase the energy requirement for
depolarization can result from myocardial ischemia/infarction,
acid-base disturbance, electrolyte abnormalities, or abnormal
antiarrhythmic drug levels

49.  Myocardial ischaemia/infarct
 Electrolyte disturbance
 Acidosis or alkalosis
 Hypoxia or hypercapnia
 Abnormal antiarrythmic drug level especially Class
I and beta blockers

50.  Loss of pacing artifact in ECG in the absence of
spontaneous QRS wave

51. 1. Absence of ‘P’or ‘QRS’ wave following atrial or
ventricular artifact in ECG

52. 1. Pacing artifact in the middle of spontaneous ‘P’ or
‘QRS’ wave -no change in automatic interval

53.  Myocardial ischaemia/infarct
 Electrolyte disturbance
 Acidosis or alkalosis
 Hypoxia or hypercapnia
 Abnormal antiarrythmic drug level especially Class
I and beta blockers

54.  Temporary pacing can be initiated
 Disturbances in electrolyte balance, antiarrhythmic
drug levels, and acid-base equilibrium should be
investigated and corrected
 Sympathomimetic drugs can decrease depolarization
threshold or increase chronotropicity (or both)
 Causes of myocardial ischemia should be sought and
corrected

58.  Position defibrillation/cardioversion pads or paddles
as far as possible from the pulse generator
 Position defibrillation/cardioversion pads or paddles
perpendicular to the major axis of the CRMD to the
extent possible by placing them in an anterior
posterior location
 Use a clinically appropriate energy output
 Post shock interrogation/ reprogramming

60. Anaesthetic management
Preoperative
Assessment
History Examination Investigations
Preparation
Intraoperative
Monitoring Conduct
Regional General
Postoperative

61. Anaesthetic management
Preoperative
Assessment
History Examination Investigations
Preparation
Intraoperative
Monitoring Conduct
Regional General
Postoperative

62.  Device interrogation - For non-reprogrammed devices,
most manufacturers recommend interrogation to ensure
proper functioning and acceptable remaining battery life
if any electrosurgery was used
 Reprogramming- A Pacemaker that was reprogrammed
for the perioperative period should be reset
appropriately
 Monitoring- Continuously monitor cardiac rate and
rhythm and have backup pacing and defibrillation
equipment immediately available throughout the
immediatepostoperative period

63.  Shivering and fasciculation should be avoided
 Ventilation must be controlled and constant,otherwise
change pacemaker to asynchronous mode
 Function of pacemaker should be checked before and
after initiation of mechanical ventilation

65.  Coagulation current has no effect
 Cutting (high frequency) current can suppress bipolar
demand ventricular pacing
 Rx-convert preoperatively into asynchronous mode

66.  Therapeutic radiation can damage the complementary
metal oxide semiconductors (CMOS) that are the parts
of most modern pacemakers
 Doses in excess of 5000 rads are required to cause
pacemaker malfunction but as little as 1000 rads may
induce pacemaker failure or cause runaway pacemaker
 If pacemaker cannot be shielded from the field of
radiation, consideration should be given to
reimplanting the pacemaker generator at distant site

67.  Avoid focusing the lithotripsy beam near the pulse
generator
 Atrial pacing and rate adaptive function need to be
disabled
 Contraindicated in patients with piezoelectric circuit
implanted in abdominal wall

68.  Three types of powerful forces exist in the MRI suite
Static Magnetic Field: Torque effect on pulse generator
Radiofrequency Field (RF) :can cause interference with
pacemaker output circuits resulting in rapid pacing at
multiple of frequency between 60–300 bpm causing rapid
pacing rate
Gradient Magnetic Field: Magnetic field gradient closes
magnetic reed switch

69.  ECT is safe in patient with pacemaker, little current
pass through heart
 Seizures may cause inappropriate activation of
AICD and rate adaptive feature of pacemaker
 Pacemaker should be changed to asynchronous
mode, ECG monitoring is must
 In patients with inactivated AICD be prepared for
external defibrillation if VT/VF occurs

70.  TENS unit consists of several electrodes placed on the
skin and connected to a pulse generator that applies
20 μsec rectangular pulses of 1 to 200 V and 0 to 60
mA at a frequency of 20 to 110 Hz.
 Adverse interaction between these devices has been
frequently reported, so these patients should be
monitored during initial application of TENS

71.  Contact pacemaker or AICD clinic or manufacturer
 Reprogram the device function in selective group
of patients
 Monitoring and anesthesia technique with due
considerations to patients CVS status
 Avoid electrocautery use. If necessary consider use
of bipolar or harmonic scalpel

72.  Monitor ECG with interference. Frequently check
for pulse
 Diathermy should not be used within 15 cm from
pulse generator
 Frequency should be 1 second burst in every 10
seconds and Use minimum current
 Be sure about the availability of temporary pacing,
defibrillator and drugs for resuscitation

73.  Avoid drugs that cause myoclonic activity or
fasciculation
 Avoid hypothermia and shivering
 Central venous line or pulmonary artery catheter
should be used with caution
 Interrogate device following either elective or
emergency surgery at the earliest possible and
consider appropriate resetting if required

74.  Kaplan’s Cardiac Anesthesia:The Echo Era, 6thed.
 Millers anaesthesia, 8th ed.
 Clinical anaesthesia ,barash 5th ed.
 ATOTW 299 and 300 pacemakers and ICDs
 Yao and artusio Anesthesiology: Problem oriented
patient management 7th ed

75.  Short notes
Pacemakers may 2010 MD