Anesthetic Considerations In Patients with Cardiac
Pacemaker..
DR. RAHUL NORAWAT
University College of Medical Sciences & GTB Hospital,
Delhi
CONTENTS
History
Introduction
Pacing & its Indications
PM & ICD
Anesthetic considerations
History
• Battery-operated pacing devices was introduced by C. W.
Lillehei and Earl Bakken in 1958.
• In 1960, Wilson Greatbatch, created the first implantable
battery-powered device.
• Invention of the implantable cardioverter-defibrillator (ICD) in
1980 by Michael Morchower. First approved by U.S. Food and
Drug Administration (FDA) in 1985.
The development of the modern
pacemaker..
INTRODUCTION
• 30,00,000 patients worldwide have been implanted
pacemakers while 3,00,000-5,00,000 have a
Implantable Cardioverter Defibrillator (lCD).
• 1,15,000 new devices are implanted each year in U.S.
Rozner MA. Anaestheslol. 2007;20:261-268.
Temporary Pacing
Transcutaneous Pacing
Transvenous Pacing
 External electrode pads and
power device
 Large electrodes over
precordium & back at level
of heart
 Output: 0-140 mA
 Terminate: Tachyarrhythmia
 Pacing rate: 0-180 bpm
 Sensing facility (VVI pacing
possible)
 Electrode placed via
femoral, brachial, IJV or
subclavian vein
 90% success rate in absence
of fluroscopy under ECG
guidance
 Atrial J-shaped electrodes
and balloon tipped
ventricular electrodes
 Externally paced generator
with output 0-l0mA
 All pacing modes available
Temporary Pacing Indications
A. Unstable bradydysrhythmias
B. Unstable tachydysrhythmias
C. Third degree Atrioventricular block
• Endpoint reached after resolution of the problem or
permanent pacemaker implantation.
Permanent PACEMAKER
Ventricular / Atrial
channel transmits the
Pacing impulse to the
respective lead.
Power source,
Circuitry,
Channels.
Electrodes:
1. Invasive / non invasive
2. Uni /Bi polar
Designs of Electrodes
• Invasive (epicardial or
endocardial) or noninvasive
(transcutaneous or
transoesophageal)
• Bipolar (>1 electrodes
attached to
myocardium) or
unipolar (1electrode to
heart and other to
remote location)
Ring
Electrode
Tip Electrode
Indication of Permanent Pacing
A. Sinus Node Dysfunction - Symptomatic diseases of
impulse formation.
 Sinus bradycardia, sinus pause or arrest, or sinoatrial
block, chronotropic incompetence.
 Often associated with paroxysmal SVTs.
 5O% implantation.
B. Atrial Fibrillation - Dual site atrial pacing to decrease
intra-atrial conduction time.
Indications cont..
C. AV Block: Due to ischaemic / congenital /
degenerative / inflammatory.
 Block within HIS Purkinje system more malignant.
 Class I - 3⁰ block with symptomatic bradycardia,
documented asystole, escape rate <40 bpm, postop block
unlikely to resolve, NM disease with block.
 Class II — Asymptomatic 3⁰ block, asymptomatic Type II 2⁰
block, asymptomatic Type I 2 ⁰ block at or below bundle of
HIS.
D. Chronic BBB likely to progress to CHB.
Indications cont..
E. Miscellaneous
• Hypertrophic Obstructive Cardiomyopathy,
• Dilated cardiomyopathy,
• Hypersensitive Carotid Sinus Syndrome & Neurogenic
Syncope,
• Cardiac Transplant,
• Prolonged QT interval,
• LV systolic dysfunction – biventricular / septal.
Generic Pacemaker Codes
The North American Society of Pacing and Electrophysiology (NASPE)
and British Pacing and Electrophysiology Group (BPEG) Pacemaker
codes.
NBG Pacemaker Codes:
Position III: Response(s) to Sensing
• I (Inhibited): The chamber is paced unless intrinsic electrical
activity is detected during the pacing interval.
• T (Triggered): The pacing device will emit a pulse only in
response to sensed event. Used for testing device.
• D (Dual): Provides AV synchrony.
Pacing device emit’s atrial pulse if no sensed atrial event takes
place within timeframe, once an atrial event has occurred
(native or paced), the pacing device will ensure that a ventricular
event follows.
Position IV: Programmability
very sensitive
Position V: Multisite Pacing
• With 2002 revision of the NBG. the fifth column describes
multisite pacing functionality .
• Atrial multisite pacing might prevent atrial fibrillation.
• Ventricular multisite pacing is an acceptable means of pacing
patients with dilated cardiomyopathy .
Types of Pacing Modes
1. Asynchronous
• AOO / VOO / DOO Asynchronous atrial / ventricular /
atrioventricular sequential, fixed rate pacing, regardless to
underlying cardiac rhythm.
• Used safely in cases with NO ventricular activity.
• Disadvantages:
– Competes with patient’s intrinsic rhythm & results in
induction of tachyarrythmias.
– Continuous pacing wastes energy & decreases battery halflife.
Types of Pacing Modes cont..
2. Single Chamber Atrial Pacing (AAI, AAT)
• Atrial-only antibradycardia pacing.
• Used sinus arrest and sinus bradycardia provided AV
conduction is adequate.
• Inappropriate for chronic AF & long ventricular pauses.
• A single pacing lead with electrode in RA, senses intrinsic P
wave & causes inhibition or triggering of pacemaker.
Types of Pacing Modes cont..
3. Single Chamber Ventricular Pacing (VVI, VVT)
• Ventricular-only antibradycardia pacing.
• Indicated complete heart block with chronic atrial flutter, AF &
long ventricular pauses.
• Senses intrinsic R wave & thus inhibits or triggers pacemaker
function. No atrial sensing; thus, no AV synchrony.
Types of Pacing Modes cont..
4.
Dual Chamber AV Sequential Pacing (DDD,
DVI, DDI, VDD)
• Two leads: unipolar or bipolar are used. Atrium is stimulated
first , then after an adjustable PR interval ventricle is
stimulated .
• Preserve the normal atrioventricular contraction sequence.
• Indicated AV block, carotid sinus syncope & sinus node
disease.
• DDD: After any sensed or paced atrial event, an intrinsic
ventricular event must occur before expiration of AV timer.
• Advantage: Generate sinus rhythm & beneficial where atrial
contraction is important for ventricular filling (aortic stenosis).
• Disadvantage: Pacemaker-mediated tachycardia (PMT) due to
ventriculoatrial conduction, which triggers a ventricular
depolarization leading to PMT. can be overcome by careful
programming.
• DDI: Ventricle is paced only when no intrinsic ventricular
activity . Used in paroxysmal atrial fibrillation.
• VDD: Used in patient with AV nodal dysfunction but intact SA
node function.
a) DDD pacing in patient with normal SA node function and normal AV node function.
b) DDD pacing in patient with normal SA node function and abnormal AV node function.
c) DDD pacing in patient with abnormal SA node function and abnormal AV node function.
British pacing
and electro
physiology group
recommended
pacemaker
modes.
PACEMAKER FAILURE
• Pacemaker failure has three etiologies:
1) Failure to capture:
a. Myocardial ischemia/infarction,
b. Acid-base disturbance,
c. Electrolyte abnormalities,
d. Abnormal antiarrhythmic drug levels.
e. External pacing might further inhibit pacemaker.
2) Lead failure,
3) Generator failure.
Implantable
Cardioverter
Defibrillator
ICD
• Battery powered device to
deliver sufficient energy to
terminate VT / VF.
• Superior to anti-arrhythmic
therapy in preventing death
in malignant ventricular
tachy-dysrhythmias.
• ICD use rate criteria to
detect VF
• Have VT detection
algorithms based on
RR interval
• Tachycardia with cycle
length less than VF
detection interval
initiates VT therapy
Indications for ICDs
A.
B.
C.
D.
E.
F.
G.
Ventricular Tachycardia
Ventricular Fibrillation
Brugada Syndrome (RBBB, ST-segment elevation in V1 to V3)
Arrhythmogenic RV Dysplasia
Long Q-T Syndrome
Hypertrophic cardiomyopathy
Prophylactic use in patient who has cardiomyopathy with
EF ≤ 35% (SCD-HeFT) & Post-MI patients with EF ≤ 30% .
Generic Defibrillator Code (NBD):
NASPE/BPEG
Effect of Magnet
• Each PM/ICD is programmed to respond in a specific manner
to magnet placement.
• Magnet usually result in pacemaker to switch to
asynchronous mode.
• A slower than expected (≥10%) magnet rate is a marker for
battery depletion.
• Magnet never turn off pacemaker.
• ICD will be inhibited to deliver antitachycardia therapy when
magnet is applied.
• Pacemaker function of ICD is not inhibited.
Magnet application to a VVI pacemaker.
Magnet application
Normal sinus rhythm with
normal AV conduction
Fixed rate , ventricular pacing
Anesthetic Considerations
Practice Advisory for the Perioperative Management of Patients with Cardiac Rhythm
Management Devices, ASA , Anesthesiology 2005; 103:186–198.
Preoperative Evaluation
• Establish that patient has a cardiac rhythm
management device (CRMD).
 Detailed focused history (patient interview, medical
records review, review CXR, ECG, SE).
 Physical examination (check for scars, palpate for device).
• Define the type of CRMD.
 Obtain manufacturer’s identification card.
 Get CXR if no other data available.
Single chamber pacemaker
Dual chamber pacemaker with displaced right atrial lead
• Determine dependency on pacing function.
 H/o symptomatic bradyarrhythmia resulting in CRMD
implantation.
 H/o successful atrioventricular nodal ablation.
 Inadequate escape rhythm at lowest programmable pacing
rate.
• Determine CRMD function.
 Interrogate device (consult cardiologist or PM-ICD service).
 Determine whether the device will capture when it paces.
 Consider contacting the manufacturer for perioperative
recommendations.
Preoperative Preparation
• Determine whether EMI is likely to occur during the
procedure.
• Determine whether reprogramming pacing function to
asynchronous mode or disabling rate responsive function is
advantageous.
• Suspend antitachyarrhythmia functions if present.
• Advise surgeon to consider use of a bipolar electrocautery or
ultrasonic (harmonic) scalpel.
• Temporary pacing and defibrillation equipment should be
immediately available.
• Evaluate the possible effects of anesthetic techniques and of
procedure on CRMD function.
Intraoperative Management
• Monitor operation of CRMD.
 ECG per ASA standard.
 Monitor peripheral pulse (manual pulse palpation, pulse
oximeter plethysmogram, arterial line).
 HOCM patients need beat-to-beat cardiac output
monitoring.
• Though anaesthetic techniques dont influence CRMD function,
the anaesthetic-induced changes (HR / rhythm / ischaemia)
may induce unexpected CRMD responses
Factors affecting pacing thresholds
Increase
Decrease
• 1-4 weeks after implantation
• Myocardial
ischaemia/infaction
• Hypothermia,
hypothyroidism
• Hyperkalaemia,
acidosis/alkalosis
• Antiarrythmics
• Severe hypoxia &
hypoglycaemia.
•
•
•
•
•
•
•
Increased catecholamines
Stress, anxiety
Sympathomimetic drugs
Anticholinergics
Glucocorticoides
Hyperthyroidism
Hypermetabolic status.
• Manage potential CRMD dysfunction due to EMI.
1. Electrocautery.
 Assure that electrosurgical receiving plate is positioned so
that current pathway does not pass through CRMD.
 Advise surgeons to avoid proximity of cautery to PM or leads.
 Advise surgeons to use short, intermittent, and irregular
bursts at the lowest feasible energy levels.
 Advise surgeons to reconsider use of bipolar electrocautery
system.
2. Radiofrequency ablation.
 Advise surgeons to avoid direct contact between the ablation
catheter and PM and leads.
 Advise surgeons to keep radiofrequency current path as far
away from PM and leads.
3. Lithotripsy.
 Advise surgeons to avoid focusing the lithotripsy beam near
pulse generator.
 If the lithotripsy system triggers on the R wave, consider
preoperative disabling of atrial pacing.
4. MRI.
 MRI is generally contraindicated in patients with CRMDs.
 If MRI must be performed, consult with the ordering
physician, cardiologist, radiologist and CRMD manufacturer.
5. Radiation therapy.
 Radiation therapy can be safely performed.
 Surgically relocate the CRMD if the device will be in the field
of radiation.
6. Electroconvulsive therapy.
 No significant damage if CRMD disabled
 Consult with the ordering physician, cardiologist, CRMD
manufacturer.
• Emergency defibrillation or cardioversion.
1. For a patient with ICD and magnet-disabled or programmingdisabled therapies:
 Advise surgeons to terminate all sources of EMI while magnet
is removed.
 Remove the magnet or reprogramming to reenable
antitachycardia therapies.
 Observe patient & the monitors for appropriate CRMD
therapy.
 If the above activities do not restore ICD function, proceed
with emergency external defibrillation or cardioversion.
2. For external defibrillation:
Lt pectoral implant
showing acceptable
anterior-apex pad
placement
Left or right or left pectoral implant
showing recommended anteriorposterior pad placement
View of anteriorposterior pad
placement
 If its technically impossible, defibrillate patient in the quickest
possible way and be prepared to provide pacing through
other routes.
Postoperative Management
• Continuously monitor HR & rhythm.
• Have backup pacing & defibrillation equipment available
throughout the immediate postoperative period.
• Interrogate and restore CRMD function in the immediate
postoperative period.
 Restore all antitachyarrhythmic therapies in ICDs.
 Assure that all other settings of the CRMD are appropriate.
SUMMARY
References
• Practice Advisory for the Perioperative Management of Patients
with Cardiac Rhythm Management Devices: Pacemakers and
Implantable Cardioverter Defibrillators, ASA , Anesthesiology 2005;
103: 186–198.
• T. V. Salukhe, D. Dob and R. Sutton, Pacemakers and defibrillators:
anaesthetic implications, Br J Anaesth 2004; 93: 95-104.
• ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac
Rhythm Abnormalities, J. Am. Coll. Cardiol. 2008; 51; e1-e62
(http://content.onlinejacc.org/cgi/content/full/51/21/e1)
• Kaplan’s Cardiac Anesthesia; 5th edition.
• Miller’s Anesthesia; 7th edition.
• Stoelting’s Anesthesia & Co-existing Disease; 5th edition.
THANK YOU..