Transcript Slide 1

By
Ahmed M. Shehata
Assistant lecturer
INTRODUCTION
 30,000,000 patients worldwide have been
implanted pacemakers while 3,000,000-
5,000,000 have a Implantable Cardioverter
Defibrillator (lCD).
115,000 new devices are implanted each
year in U.S.
Temporary Pacing
Transcutaneous Pacing
Transvenous Pacing
 External electrode pads
 Electrode placed via
and power device
 Large electrodes over
precordium & back at level
of heart
 Output: up to 140 mA
 Terminate: Tachyarrhythmia
 Pacing rate: up to 180 bpm
 Sensing facility (VVI
pacing possible)
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 up to l0mA
 All pacing modes available
Temporary Pacing Indications
A. Unstable bradydysrhythmias
B. Unstable tachydysrhythmias
C. Third degree Atrioventricular block
Endpoint: resolution of the problem or
permanent pacemaker implantation.
Permanent PACEMAKER
Ventricular / Atrial
channel transmits
the Pacing impulse
to the respective
lead.
Power source,
Circuit
Electrodes:
1. Uni /Bi polar
Indication of Permanent Pacing
A. Sinus Node Dysfunction - Symptomatic diseases
of impulse formation.
 Sinus bradycardia, sinus pause or arrest, or sinoatrial
block.
 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.
 3rd block with symptomatic bradycardia, documented
asystole.
 Asymptomatic 3rd block, asymptomatic Type II 2nd
block, asymptomatic Type I 2nd block .
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.
Position III: Response 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.
 D (Dual): Provides AV synchrony.
Pacing device emit’s atrial pulse if no sensed atrial event
takes place, once an atrial event has occurred , the pacing
device will ensure that a ventricular event follows.
Position IV: Programmability
 Vibration sensor
 Motion sensor
 Minute ventilation sensor
 the sensor detects “exercise,” it increases the
pacing rate (termed “sensor-indicated rate”). As
the exercise tapers, this sensor-indicated rate
returns to the programmed lower rate.
Position V: Multisite Pacing
 With 2002 revision the, fifth column describes multisite
pacing.
 Atrial multisite pacing might prevent atrial fibrillation.
 Ventricular multisite pacing is an acceptable means of
pacing patients with dilated cardiomyopathy .
modes of pacing
4 modes of pacing:
 - Asynchronous (AOO, VOO and DOO)
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 half-life.
 - Single-chamber deman
Atrial-only antibradycardia pacing.
Inappropriate for chronic AF & long ventricular pauses.
modes of pacing cont..
 Single Chamber Ventricular Pacing (VVI, VVT)
- Ventricular-only antibradycardia pacing.
- Indicated complete heart block with chronic atrial flutter, AF & long
ventricular pauses.
 Dual Chamber AV Sequential Pacing (DDD, DVI,
DDI, VDD)
- Preserve the normal atrioventricular contraction sequence.
- Indicated AV block, carotid sinus syncope & sinus node disease.
PACEMAKER FAILURE
 Pacemaker failure has three aetiologies:
1) Failure to capture: (the generator continues to fire but no myocardial
depolarization takes place)
a.
b.
c.
d.
e.
Myocardial ischemia/infarction,
Acid-base disturbance,
Electrolyte abnormalities,
Abnormal antiarrhythmic drug levels.
External pacing might further inhibit pacemaker.
2) Lead failure,
3) Generator failure.
Pacemaker syndrome
 occurs in patients with ventricular pacemakers.
 The awake patient may experience syncope,
breathlessness, postural hypotension, and other
symptoms associated with a low cardiac output.
 pacemaker is stimulating the venticles of the heart so,
activation of the heart starts in the ventricles and then
spreads upward to the atria. So, the normal activation
of the heart electrically is reversed. the atria beat
against closed valves.
ICD (Implantable Cardioverter Defibrillator)
 Battery powered device
to deliver sufficient
energy to terminate VT /
VF.
 all discharges are painful
 Superior to antiarrhythmic therapy in
preventing death in
ventricular tachyarrhythmias.
Indications for ICDs
A. Ventricular Tachycardia
B. Ventricular Fibrillation
C. Brugada Syndrome (RBBB, ST-segment elevation in V1 to V3)
D. Arrhythmogenic RV Dysplasia
E. Long Q-T Syndrome
F. Hypertrophic cardiomyopathy
G. Prophylactic use in patient who has cardiomyopathy with
EF ≤ 35% & Post-MI patients with EF ≤ 30% .
Generic Defibrillator Code
NASPE/BPEG:
Effect of Magnet
 Each PM/ICD is programmed to respond in a specific
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manner to magnet placement.
Magnet usually result in pacemaker to switch to
asynchronous mode.
Magnet never turn off pacemaker.
ICD will be inhibited to deliver antitachycardia therapy
when magnet is applied.
Pacemaker function of ICD is not inhibited.
Effect of Magnet
 Magnet placement is not an advisable practice to
employ in all cases.
 If the patient is not pacemaker dependent, an
asynchronous mode will compete with the intrinsic
rhythm.
 Some types of pacemakers, application of a magnetic
field is a step required to initiate reprogramming of
the generator.
 Random reprogramming when exposed to magnetic
fields.
Magnet application to a VVI pacemaker.
Magnet application
Normal sinus rhythm
with normal AV
conduction
Fixed rate , ventricular pacing
Anesthetic Considerations
Preoperative Evaluation
 History; special attention for CV system, AMI, arrhythmia,
underlying rhythm
 medical records review, review CXR, ECG…
 Physical examination (check for scars, palpate for device).
 Direct interrogation with a programmer remains the only reliable
method for evaluation; type, dependency on pacing, programmed
function.
 Obtain manufacturer’s identification card.
 Get CXR if no other data available.
Anesthetic Considerations
Preoperative Evaluation cont..
 Permenant pacemaker reprogramming:
- Asynchronous pacing mode at a rate greater than
the patient’s underlying rate
 ICD reprogramming:
- Disabling the antitachycardia therapie function
always indicated
- With pacing function → Disabling the antitachycardia therapy + Asynchronous pacing mode
Single chamber pacemaker
Dual chamber pacemaker
Anesthetic Considerations
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 or not
 Suspend antitachyarrhythmia functions if present.
Anesthetic Considerations
Preoperative Preparation cont…
 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 PM function.
Anesthetic Considerations
Intraoperative Management
 Monitor operation of PM by:
 ECG.
 Monitor peripheral pulse (manual pulse palpation, pulse
oximeter plethysmogram, arterial line).
 Because of the vasodilating effects of potent inhaled
anesthetics, pacemaker syndrome in the anesthetized
patient will be more significant than in the awake patient
 Preservation of intrinsic rhythm of the patient with a
demand pacemaker is achieved by preventing bradycardia.
Anesthetic Considerations
Intraoperative Management cont..
 beta agonists have potent inotropic , chronotropic and
vasodilatory effects. This causes an increase in myocardial
oxygen requirements and a decrease in systemic vascular
resistance. Ischemia, myocardial infarction, or
dysrhythmias may result.
 when suxamethonium is to be used in a patient with a
permanent pacemaker, consideration should be given to
reprogramming the pacemaker to asynchronous mode
before induction of anaesthesia.
Factors affecting pacing response
decrease
increase
 1-4 weeks after
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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 PM dysfunction due to EMI.
1. Electrocautery.
 Assure that electrosurgical receiving plate is positioned so that
current pathway does not pass through PM.
 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.
4. MRI.
 MRI is generally contraindicated
 If MRI must be performed, consult with the ordering
physician, cardiologist, radiologist and PM manufacturer.
5. Radiation therapy.
 Radiation therapy can be safely performed.
 Surgically relocate the PM if the device will be in the field
of radiation.
6. Electroconvulsive therapy.
 No significant damage if PM disabled
 Consult with the ordering physician, cardiologist, PM
manufacturer.
Postoperative Management
 Continuously monitor HR & rhythm.
 Have backup pacing & defibrillation equipment available
throughout the immediate postoperative period.
 Interrogate and restore PM function in the immediate
postoperative period.
 Restore all antitachyarrhythmic therapies in ICDs.
 Assure that all other settings of the PM are appropriate.
References
 Practice Advisory for the Perioperative Management of Patients
with Cardiac Rhythm Management Devices: Pacemakers and
Implantable Cardioverter Defibrillators, ASA , Anesthesiology
103: 186–198.
 T. V. Salukhe, D. Dob and R. Sutton, Pacemakers and
defibrillators: anaesthetic implications, Br J Anaesth; 93: 95-104.
 ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of
Cardiac Rhythm Abnormalities, J. Am. Coll. Cardiol.; 51; e1-e62
 Kaplan’s Cardiac Anesthesia.
 Miller’s Anesthesia.
 Stoelting’s Anesthesia & Co-existing Disease