Download G Govender Perioperative management of patients

01 June 2012
No. 17
Perioperative management of patients
with implanted pacemakers
G Govender
Commentator: N Gokal
Moderator: A Maharaj
Department of Anaesthetics
CONTENTS
INTRODUCTION ................................................................................................... 3
PACEMAKERS ..................................................................................................... 3
Indications .......................................................................................................... 4
Classifications of Pacemakers ............................................................................ 5
ELECTIVE PATIENT ............................................................................................. 8
Preoperative management ............................................................................... 10
Intraoperative Care ........................................................................................... 13
Postoperative Care ........................................................................................... 14
THE EMERGENCY PATIENT ............................................................................. 17
PRINCIPALS OF MAGNET USE ........................................................................ 19
DEVICE MANAGEMENT .................................................................................... 20
PAEDIATRICS PATIENT CONSIDERATIONS .................................................. 20
OTHER IMPLANTED CARDIAC DEVICES (IMPLANTABLE CARDIOVERTER
DEFIBRILLATORS)............................................................................................. 21
CONCLUSION .................................................................................................... 22
REFERENCES.................................................................................................... 23
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INTRODUCTION
As an anaesthetist, the perioperative period poses unique challenges for us when
dealing with patients with implanted pacemakers. The potential problems that can
occur in patients with a pacemaker in the perioperative setting are detailed. In my
talk I provide recommendations for the appropriate preoperative evaluation,
intraoperative management and postoperative care of the patient with a
pacemaker undergoing surgical procedure to ensure the highest degree of patient
safety.
PACEMAKERS
A pacemaker is a medical device that uses electrical impulses, delivered by
electrodes contacting the heart muscles, to regulate the beating of the heart. The
primary purpose of a pacemaker is to maintain an adequate heart rate, either
because of the heart's intrinsic pacemaker is not fast enough, or there is a block in
the heart's electrical conduction system. Modern pacemakers are externally
programmable and allow the cardiologist to select the optimum pacing modes for
individual patients. Some combine a pacemaker and defibrillator in a single
implantable device. Others have multiple electrodes stimulating differing positions
within the heart to improve synchronisation of the heart. The term “Cardiac
Implantable Electronic Device (CIED)” is often used, but this term also refers to
any cardiac resynchronization device.
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Indications
The decision to implant a permanent pacemaker is an important one and should
be based on solid clinical evidence. A joint committee of the American College of
Cardiology (ACC) and the American Heart Association (AHA) was formed in the
1980s to provide uniform criteria for pacemaker implantation. These guidelines
were first published in 1984 and most recently revised in 2008. It must be realized,
however, that medicine is a constantly changing science, and absolute and
relative indications for permanent pacing may change as a result of advances in
the diagnosis and treatment of arrhythmias.
Specific indications for pacing include:
- Sinus node dysfunction
- AV block (Congenital, acquired, surgical)
- Bifascicular and trifascicular block
- Hypersensitive Carotid Sinus Syndrome (CSS)
- [ Malignant Vasovagal Syncope (MVVS) ]
- Pacing after cardiac transplantation
- Heart Failure / HOCM / AF
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Applying Classification of Recommendations and Level of Evidence
Classifications of Pacemakers
The North American Society of Pacing and Electrophysiology (NASPE) and British
Pacing and Electrophysiology Group (BPEG) published as a joint effort the
pacemaker code. This joint project is known as the NBG pacemaker code. The
NBG was initially published in 1983 and was last revised in 2002. It describes the
five letter code for operation of implantable pacemakers and defibrillators.
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The first two positions of this code (Chamber Paced and Sensed) are relatively
straightforward.
The third position is the most confusing. The most frequently used programs are
the DDD (dual chamber pacing and sensing, both triggered and inhibited mode),
VVI (for single chamber, ventricular pacing in the inhibited mode), VDD
(ventricular pacing with atrial tracking), and DDI (dual chamber pacing and
sensing, but inhibited mode only).
The third position is described as follows:
D - (Dual): In DDD pacemakers, atrial pacing is in the inhibited mode (the pacing
device will emit an atrial pulse if the atrium does not contract). In DDD and VDD
pacemakers, once an atrial event has occurred (whether paced or native) the
device will ensure that an atrial event follows.
I - (inhibited): The device will pulse to the appropriate chamber unless it detects
intrinsic electrical activity. In the DDI program, AV synchrony is provided only
when the atrial chamber is paced. If on the other hand if intrinsic atrial activity is
present, then no AV synchrony is provided by the pacemaker.
T - (triggered): Triggered mode is only used when the device is being tested. The
pacing device will emit a pulse only in response to a sensed event.
The VDD pacemaker is used for AV nodal dysfunction but intact and appropriate
sinus node behavior. DDI is rarely used as the primary mode of pacing.
The DDI pacer is used for a patient with a dual-chamber pacemaker that has
episodes of paroxysmal atrial fibrillation.
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DDI prevents high ventricular rates. Some DDD pacemakers are programmed to
enter the DDI mode when high atrial rates occur.
The fourth position, rate modulation, increases the patient’s heart rate in response
to “patient exercise”. A number of mechanisms (vibration, respiration, and
pressure) are used to detect “patient exercise”. As the exercise wanes, the sensor
indicated rate returns to the programmed mode The fifth position describes
multisite pacing functionality. Atrial multisite pacing is being investigated as way to
prevent atrial fibrillation. Ventricular multisite pacing is a treatment for pacing a
patient with dilated cardiomyopathy.
There are four types of pacemakers:
asynchronous, single-chamber
synchronous, double-chamber AV sequential, and programmable.
• Asynchronous or fixed-rate (AOO, VOO, DOO) – discharge at a preset rate that
is independent of the inherent heart rate.
• Single-chamber synchronous or demand (AAI, VVI) – discharge at a preset rate
only when the spontaneous heart rate drops below the preset rate.
• Dual-chamber AV sequential pacing (VDD, DVI, DDD) – usually uses two
electrodes, one in the atrial appendage and one in the right ventricular apex. The
atrium is stimulated to contract first, then after an adjustable PR interval, the
ventricle is stimulated.
• Programmable pacemakers – pacing rate, pulse duration, voltage output, and Rwave sensitivity are the most common programmable functions.
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Selection of pacemaker systems for patients with atrioventricular block
ELECTIVE PATIENT
The most widely appreciated potential complication with pacemakers in the
operative setting is the inappropriate sensing of electromagnetic interference
(EMI) caused by electrocautery. The consequence of such inappropriate sensing
depends on the type of pacemaker involved, patient characteristics, and device
settings.
In general, however, the result may include:
1. No effect;
2. Inappropriate inhibition of pacing;
3. Inappropriate rapid pacing
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There are some implications to device function associated with anesthesia and
surgery.
1. Damage to or reprogramming of pacemaker systems. In a few case reports,
these complications have been documented secondary to cautery use or
associated with radiotherapy or radiofrequency ablation procedures, although
the risk of these complications is considered quite low due to the incorporation
of protective circuitry in modern pacemaker technology.“Power on reset”
mode—a simple backup pacing mode (typically VVI or VOO)—may be activated
by disruption of a pacemaker’s
volatile electronic memory.
2. Anatomical consequences associated with surgical procedures—
pneumothorax with thoracotomy or cardiac surgery: such results have been
linked to changes in pacemaker function due to lead dislodgement, an increase
in impedance, particularly with unipolar pacing systems
3. Physical damage to pacemaker or leads through direct trauma
device or lead infection associated with perioperative bacteremia;
4. Physical damage (burn) to tissue associated with EMI conduction through
leads; and
5. Complications associated with the failure to return devices to preoperative
settings.
6. It should be noted that vagotonic manoeuvres or agents (rapidly acting
narcotics) may enhance conduction blockade and this effect is likely more
pronounced in patients with sinus or atrioventricular node dysfunction.
7. Depending on the nature of the surgery, alterations in fluid balance, acid base
status, electrolyte disturbances, and altered medication schedules can have an
impact on device function and propensity to arrhythmias.1
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Preoperative management
The preoperative evaluation is the cornerstone of patient safety for operative
procedures. Patient safety rests upon the clear and precise communication
between the CIED team (cardiologist, cardiac electrophysiologist, device clinic
nurses and staff) and the perioperative team (anesthesiologist, surgeon,
perioperative assessment team).
The general principles are of preoperative evaluation are:
A. Establish whether a patient has a cardiac rhythm management device.
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).
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 is available.
c. Refer to supplemental resources (e.g. manufacturer’s databases).
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.
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).
3. Consider contacting the manufacturer for perioperative recommendations
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The preoperative preparation includes the following:
A. Determine whether EMI is likely to occur during the planned procedure.
Estimate the likelihood of EMI based on the characteristicsof the proposed
surgery and the specific pacemaker. It is essential to know the location of the
pacemaker and the lead configuration to be able to assess this.
● EMI is more likely if surgery _ 15 cm from pacemaker or leads (ie,
intrathoracic, shoulder, etc) or above the umbilicus;
● EMI is more likely if monopolar cautery rather than bipolar cautery to
be used;
● EMI is more likely if long (_ 5 seconds) or frequent
(_ 5 seconds between) bursts of cautery to be used;
● EMI is more likely if the pacemaker has unipolar leads or bipolar leads
programmed in unipolar mode or with very high sensitivity.
1. Determine whether reprogramming pacing function to asynchronous mode
or disabling rate responsive function is advantageous.
2. Suspend antitachyarrhythmia functions if present.
3. Advise the individual performing the procedure to consider use of a bipolar
electrocautery system or ultrasonic (harmonic) scalpel.
4. Temporary pacing and defibrillation equipment should be immediately
available. Care should be taken to ensure pads are not within 4 to 5 cm of
the implanted pacemaker or defibrillator.
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Placement of transcutaneous pads to facilitate intraoperative external
pacing, cardioversion, or defibrillation.
B. Evaluate the possible effects of anesthetic techniques and of the procedure on
CIED function and patient-CIED interactions
Like all aspects of surgery, ensuring optimal pacemaker-related outcomes
requires careful planning that should start as soon as possible after the decision is
made to undertake surgery. The details of this planning will depend on the
urgency of surgery (emergent vs elective), if surgery will be performed in an
environment with onsite pacemaker support, and if surgery will be conducted on
an inpatient or outpatient basis.
If a patient is being considered for elective surgery and has a pacemaker which
has reached the point where replacement is recommended, if at all possible, the
pacemaker should be replaced before elective surgery.
Whenever possible, deliver quality healthcare in the patient’s community of
residence. But on occasion, it may be appropriate to refer the patient to another
institution for surgery to facilitate appropriate perioperative management of their
pacemaker.
Rate Modulation Technology (Rate Response)
Rate modulation technologies were developed in the 1970s to mimic physiological
heart rate increases in response to exercise.
While controversy remains relative to the clinical usefulness of universally applied
rate-modulated pacing, virtually all pacemakers implanted today have rate
modulation functions available. A variety of technologies have been investigated
and 4 main technologies remain (Table 3).
Sensor Technology
- Activity sensor
o Measures mechanical stress to piezoelectric crystal as a result of
motion or acceleration
- Minute ventilation sensor
o Measures transthoracic impedance change between pacemaker
lead and pulse generator
- QT-interval–based sensors
o Measures evoked QT interval changes as estimate of adrenergic
tone
- Contractility sensors, activity sensor-based
o Measures peak endocardial acceleration as estimate of
contractility and global
LV function
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Various intraoperative events may cause interference with the intended
interpretation of physiological changes for rate modulation and pacemaker-driven
tachycardia is described from different sources. Minute ventilation sensors, which
may erroneously interpret the signals generated by certain physiological monitors.
Similarly, myoclonia has been reported to be associated with pacemaker-driven
tachycardia, presumably by misinterpretation of muscle activity.
Interference with anesthesia management from rate modulation technologies is
uncommon but can be clinically confusing, and adverse clinical outcomes may be
seen on rare occasions.
In the case of elective surgery, it is reasonable to consider suspending rate
modulation functions.
Intraoperative Care
In addition to comprehensive general intraoperative care, the management of
patients with a pacmaker requires constant awareness of the unique issues
related to their pacemaker and the availability of specific equipment and trained
personnel .The anesthesiologist should review and document the perioperative
management plan for the device. The patient should have continuous
electrocardiographic and pulse monitoring, and the facility should be equipped
and the patient prepared for immediate institution of transcutaneous pacing,
external defibrillation, and magnet application, should the need arise.
Wherever reasonable, the literature advocates the use of magnet application to
disable ICD therapies during surgery
(when magnet function has not been disabled during device programming) rather
than reprogramming.
An abundance of clinical anecdotes of fatal outcomes and close calls associated
with the failure to restore appropriate device settings prior to discharge speak to
the importance of this issue. Though this risk is understated in the medical
literature, failure to comply places the patient at risk of death if the ICD therapies
are not reprogrammed “ON” after surgery. In the event of dysrhythmias requiring
therapy, the exact prior outpatient settings are restored immediately upon magnet
removal (with specific exceptions and the device will function as programmed.
Magnet placement may not be adequate in specific circumstances (ie, prone or
lateral positioning or when the device is incidentally within the surgical field).
In these cases, temporary reprogramming to disable ICD therapies should be
considered and alternative plans for potentially required defibrillation therapy must
be undertaken. Furthermore, there must be a clear plan for postoperative
restoration of device programming which can accommodate last-minute changes,
such as a delay or cancellation of surgery or same-day discharge. The physician
ordering the reprogramming, NOT the industry representative, has the
responsibility to ensure that the device is returned to its original settings.2
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Intraoperative monitoring and considerations
All patients with a pacemaker undergoing a procedure with a risk of EMI
interaction require cardiac rhythm monitoring, regardless of the complexity of the
procedure performed or the level of anesthesia used. Due to possible interactions
between many of the cardiac rhythm monitoring units and pacemakers, heart rate
monitoring must encompass the ability to identify the pulse, either by
plethysmography, oximetry or intraarterial pressure monitoring.
Specific problems with cardiac monitoring and pace makers
- Over counting the heart rate due to counting pacemaker spikes and QRS
complexes individually
- Inability to identify pacemaker spikes with monitor employing high
frequency filters
- Falsely “marking” artifact as a pacemaker spike
- Pacemaker initiated heart rate increase due to rate responsive
pacemaker algorithms with inappropriate response by surgical team
- Most rate sensors employ an accelerometer such that patient movement
could increase the patient’s paced rate if the sensor is not inactivated
- Minute ventilation creates a unique situation where current emitted by the
pacemaker to measure changes in thoracic impedance can be detected
by monitoring equipment and appears to be rapid pacing without capture
When gaining central venous access, guide wires should be advanced carefully
into the heart particularly if the pacemaker lead has been recently placed. Also,
guide wires should not contact the sensing electrodes of an ICD lead as this could
result in inappropriate sensing and possible ICD shock (if the ICD has not been
deactivated).
Postoperative Care
The postoperative management of a patient’s pacemaker should continue until the
patient has recovered hemodynamically from surgery and until the respective
device has been restored to appropriate outpatient settings. If a decision is made
to disable ICD therapies for ventricular tachycardia (VT) and/or ventricular
fibrillation (VF) for surgery or to change the pacing mode to avoid the effects of
EMI, it is of CRITICAL importance that a physician is responsible for ensuring that
these therapies are reinstated before ECG monitoring is discontinued.
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Particular care should also be taken when nonhospital personnel
(ie, industry representatives) are asked to reprogram devices at hospitals where
no hospital personnel are available to perform this task. Physicians caring for
pacemaker patients in these settings should be aware that industry
representatives may not be immediately available to reprogram the device and, as
noted, the physician ordering the reprogramming, NOT the industry
representative, assumes the responsibility to ensure that the device is returned to
its original settings.
A clear communication between the industry representative and the ordering
physician should be documented in the chart to ensure proper management of
these patients.
Following thoracotomy or cardiac surgery, the position of the leads, especially the
atrial lead if present, may change due to cardiac manipulation during surgery.
Postoperative device assessment is required to determine appropriate lead
function and appropriate output programming. If a change in lead function is
determined, this can usually be managed acutely with device programming
changes, but it may require lead revision once the patient has recovered from the
acute phase of surgery.
For higher-risk surgeries (cardiac, vascular, etc), for which patients are typically
managed postoperatively in an intensive care setting, other issues related to
pacemaker management may arise.
-
In patients whose device employs a minute ventilation sensor,
inappropriate rapid pacing may result if mechanical ventilator settings
cause hyperventilation. Such sensor- related pacing functions can be
disabled by reprogramming if such tachycardia is undesired.
-
Patients who are highly pacemaker-dependent will not mount a
tachycardia response to hypotension which results from hypovolemia or
sepsis. In such patients who are paced 100% of the time; it may be
desirable to reprogram the lower pacing rate to a higher rate more
appropriate to the underlying hemodynamic status. If an increased heart
rate is required emergently and reprogramming is not immediately
available, then placing a magnet may help. This step will typically
accelerate pacingto the magnet rate, which is device-specific but often _
85 beats · min_1. For devices with accelerometer sensors, repetitive
tapping over the pacemaker generator will usually cause acceleration of
the paced heart rate tothe upper sensor rate (typically 110 to 130 beats
·min_1).
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- Care should be taken in dealing with cardiogenic shock. In this setting,
although acceleration of heart rate may appear to increase cardiac
output, it does so at the expense of an increased demand for myocardial
oxygen. Several clinical trials have shown that increasing the frequency
of right ventricular pacing rate fails to improve outcomes and, in fact,
increases the risk of heart failure and death. Although increasing the
ventricular pacing rate may be appropriate for specific individuals with
non cardiogenic shock who are already 100% ventricular paced or who
have cardiac resynchronization devices, it is almost never appropriate for
patients with intrinsic conduction who have standard pacemakers or
defibrillators.
- If the patient is paced only in the atrium, then increasing the atrial pacing
rate while minimizing ventricular pacing could be appropriate.
- Finally, patients managed postoperatively in an intensive care setting will
have continuous cardiac rhythm monitoring. This will allow some flexibility
in the timing to restore outpatient settings on pacemakers which have
been reprogrammed. Although this flexibility is desirable with respect to
the availability of pacemaker clinic personnel, there should be an
established protocol in place to ensure that all pacemakers are
programmed appropriately prior to discharging the patient from a
monitored setting. As well, communication should flow back to the
patient’s usual pacemaker clinic and/or physicians regarding any
permanent changes that have been made to the original programming of
their devices.3
Postoperative evaluation
The purpose for performing a post-procedural interrogation of a pacemaker is to
assure that the device has not entered a backup safety mode and that
functionality was not damaged.
Patients who should have a post-procedure interrogation prior to leaving a cardiac
monitored setting are those whose settings were re-programmed prior to the
procedure, patients who had a major surgical procedure performed such as
cardiac surgery or vascular surgery and any patient who was at risk for or
experienced significant intraoperative events such as significant hemodynamic
alterations, cardiac arrest, ventricular tachycardia, required temporary pacing,
cardiopulmonary resuscitation or external electrical cardioversion. Patients
exposed to EMI with a high probability of affecting device function should also be
checked. The recommended timing for post-procedural pacemaker evaluation is
as follows.
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Monopolar Electrosurgery - evaluate within 1 month from procedure
External Cardioversion
- evaluate prior to discharge or transfer from cardiac
telemetry
Radiofrequency Ablation - evaluate prior to discharge or transfer from cardiac
telemetry
Electroconvulsive Therapy - evaluate within 1 month from procedure
Nerve Conduction Studies (EMG) -No additional evaluation beyond routine
Ocular Procedures
-No additional evaluation beyond routine
Therapeutic Radiation
-evaluate prior to discharge or transfer from cardiac
telemetry; remote monitoring optimal; some
instances may indicate interrogation after each
treatment
TUNA/TURP
-No additional evaluation beyond routine
Lithotripsy
- evaluate within 1 month from Procedure
Endoscopy
-No additional evaluation beyond routine
X-ray/CT Scans/Mammography -No additional evaluation beyond routine
THE EMERGENCY PATIENT
Emergent procedures create a situation where there may not be adequate time to
contact the patient’s CIED team or gather the important CIED information.
The first step is to identify the type of device. The operative team should realize
that neither patients nor their families are always clear on whether they have a
pacemaker or ICD, much less the device manufacturer or model. Patients may
use their ICD for pacing, including when pacemaker dependent.
Obtaining appropriate medical records and the patient’s CIED registration card
should be accessed, if available. Other methods to identify a CIED type include
contacting the device companies who can help to identify if a patient is in their
database and, if so, the type of device and model and year of last generator
placement. One pit fall of this approach is that patients may have had a newer
device implanted from another manufacturer. If a chest radiograph can be
examined, the type of device (ICD vs pacemaker) can be determined and often
the manufacturer’s identification marking can be noted on the generator.
A member of the CIED team should be contacted as soon as possible to provide
further recommendations or to reprogram the ICD if time allows. After identifying
that the patient has a CIED, the next step is to determine whether the patient is
pacemaker dependent. If pacemaker spikes are noted in front of all or most P
wave or QRS complexes, the assumption for the purpose of an emergent surgery
is that the patient is pacemaker dependent.
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If the procedure is likely to involve extensive monopolar electrocautery, placing a
magnet over a pacemaker generator would be an appropriate solution. In the case
of a pacemaker dependent patient using an ICD for his/her pacemaker function, a
magnet placed over the ICD will not result in asynchronous pacing.
This situation would require re-programming of the device to assure asynchronous
pacing. If re-programming is not an option given the urgency of the need to
perform the procedure, then careful attention to short cautery bursts (_5 seconds)
to minimize pacing inhibition or placement of a temporary transvenous pacemaker
will be required.
For patients not identified to be pacemaker dependent or for lower risk procedures
(below the umbilicus), a magnet should be available in the room in case there is
the development of bradycardia, which once applied will result in asynchronous
pacing (pacemakers only).
The emergent procedure for all patients with an ICD requires placing a magnet
over the generator if the device cannot be re-programmed in order to suspend
tachyarrhythmia detection. Exceptions might be a surgical procedure on the lower
extremities where the chance of false detection is very low.
If the situation requires the need to rapidly take a critically ill patient for an
emergent surgical procedure and time does not permit gathering CIED patient
information, the surgical team should secure a magnet over an identified CIED,
watching the cardiac rhythm to note pacemaker activity and observe for
pacemaker inhibition. If the latter occurs, short bursts of electrocautery or
temporary pacing are the only options.
All patients with a CIED undergoing an emergent procedure require placement of
transcutaneous patches for both emergent defibrillation and emergent
transcutaneous pacing (anterior/posterior pad placement). Cardiac monitoring
should be with plethysmography or by an arterial line. In all cases of emergent
surgery, the patient’s CIED system must be evaluated prior to leaving the
monitored environment either in the recovery room or prior to removing the patient
from cardiac monitoring.
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PRINCIPALS OF MAGNET USE
Pacemakers
The response to magnet placement (rate, mode, and output)
is manufacturer- and model-specific, and some devices can be programmed to
have no response to magnet placement. The function of magnet placement is
both diagnostic and therapeutic; hence, the battery capacity of most devices can
be inferred from the response to magnet placement. Most modern pacemakers
will respond to a magnet by pacing asynchronously as long as the magnet is
applied. There are some commonly held misconceptions about magnet placement
though adverse events are considered rare in clinical practice:
1. The theoretical risk of sustained R-on-T arrhythmia when a device is
programmed to the asynchronous mode (magnet or programming) is
considered to be extremely low.
2. Rare instances of unintended device reprogramming have been reported
associated with the confluence of end-of-life battery condition, magnet
movement, and simultaneous electrocautery interference. The device should
be interrogated if there is concern that such a situation has been
encountered.
3. The effect of magnet application is terminated immediately upon removal of
the magnet. There are rare reportsof device failure with magnet application.
4. Of importance, application of a magnet will ensure pacing in pacemakerdependent patients if EMI inhibits pacing during electrocautery use in
surgery. Magnet application could also be useful in other circumstances (eg,
when over sensing inhibits pacing or when terminating a pacemakermediatedtachycardia).4
Below are the 3 models of pacemakers currently being implanted at the
Albert Lutuli Central Hospital and their response to a magnet.
Medtronic
Two beats at 100 beats · min_1, beat at 90 beats · min_1,
then 85 beats · min_1
St Jude Medical
Three beats at 100 beats · min_1 or 98 beats ·min_1, then
85 beats · min_1 until magnet removed
Biotronik
Ten beats asynchronous at 90 beats · min_1 or 80 beats
·min_1, then subsequent at programmed rate less 11%
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DEVICE MANAGEMENT
Whenever possible, planning for perioperative device management should be a
collaborative process involving the patient’s CEID team. Guided by the following
recommendations, this approach will ensure optimum planning to meet the
patient’s specific needs.
1.
2.
Operations with minimal or no electrocautery
- No change to pacemaker programming; have magnet available.
Operations with significant or unavoidable electrocautery
-A. Patient is pacemaker dependent
● If device is continuously accessible and visible and device responds
continuously to magnet placement, use magnet to initiate asynchronous
pacing.
● If device is not accessible or device does not respond continuously to magnet
placement, then reprogram device to asynchronous mode at the start of the
procedure.
-B. Patient is not pacemaker dependent
● If device is continuously accessible and visible and device responds
continuously to magnet placement, have magnet available to intervene if
necessary.
● If device is not continuously accessible and operative circumstances require a
more physiologic rate, then consult with the CRD clinic to consider
reprogramming to a physiologically acceptable rate for the duration of the
procedure.
3.
Consider suspending rate modulation therapies if enabled.
PAEDIATRICS PATIENT CONSIDERATIONS
Although it is relatively uncommon for paediatric patients to have an implanted
pacemakers compared with the adult population, such patients do present with the
need for operative management.
While all of the general principles apply to paediatric patients, there are a several
important issues to emphasize in managing a paediatric patient with a pacemaker
perioperatively.
There are relatively fewer centres that manage paediatric pacemakers and
therefore, for elective cases, management at their home centre, or one familiar
with their underlying cardiac condition, is likely most appropriate. For emergency
surgery where this is not possible, communication with the tertiary centre
managing the pacemaker is imperative.
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The most common indication for pacing in the paediatric population is complete
heart block following cardiac surgery. Because congenital heart disease frequently
exists in the presence of other organ involvement, these individuals may be
required to undergo non cardiac surgery.
These patients usually have competent sinus node function and thus can respond
to the stress of the intervention appropriately; however, upper rate behaviour
programming is particularly important in young patients, whose sinus rates will
approach the upper capacity of the device when the patient is stressed. Such
complex patients usually have epicardial devices and leads and familiarity with the
location of these is essential before embarking on surgery.
OTHER IMPLANTED CARDIAC DEVICES (IMPLANTABLE CARDIOVERTER
DEFIBRILLATORS)
Current ICD models have 2 distinct functions (ie, tachyarrhythmia detection and
treatment and conventional bradyarrhythmia pacing therapy). The application of a
magnet over an ICD will suspend tachyarrhythmia detection and treatment while
the magnet is positioned over the device, except in devices where this function is
specifically programmed off.
Conversely, the magnet will not affect the pacing capability of the ICD.
Consequently, appropriate positioning of a magnet over an ICD will cause the
device to ignore EMI (and true tachyarrhythmias) and no ICD therapies will be
delivered;however, EMI may inhibit the function of the pacemaker component of
the device and cause asystole.
In some devices, unexpected magnet function may occur.
Communication with the patient’s usual physician and/or clinic can help determine
how the device is expected to function with magnet application. Some devices
may have their magnet response turned off, in which case, the magnet will not
inhibit therapies. In emergent situations where the device response to the magnet
cannot be determined, careful monitoring is required during the procedure to
determine the response of the device to the EMI (cautery). If inappropriate
therapies, such as shock or rapid ATP, should occur, shorter bursts of cautery
with_5-second pauses between bursts or switching to bipolar cautery may be
required.
If a patient develops VT or VF while the ICD has been disabled by a magnet, the
arrhythmia can be managed by removal of the magnet (which will allow the ICD to
deliver therapy) or by delivery of an external defibrillator shock. If the use of
external pacing or defibrillation is considered necessary, pads should be placed
on the patient in the posteroapical fashion,ensuring the apical pad is at least 5 cm
from the location of the ICD5
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CONCLUSION
In this summary, I have provided recommendations that are based upon the
available literature and input from experts in the field: both health care providers
and representatives from the companies that manufacture these devices.
The approach to these patients will continue to be based largely upon personal
experience. I refer you to the main various Consensus Documents for a more
detailed discussion of the perioperative management of the patient with
pacemakers. I cannot overemphasize that the best care provided to such patients
will be achieved through a careful preoperative assessment of the patient.
This assessment relies upon shared communication between the pivotal
physicians involved in the patient’s procedure. It is not acceptable for a patient to
arrive in a pre-operative holding area and a “discovery” be made of a pacemaker
o. This scenario generally prompts an anxious call to a cardiology team member,
who likely is not familiar with the patient but nevertheless must assure the
patient’s safety—while a surgical team is waiting to begin the procedure.
A complete and thoughtful preoperative evaluation by the surgical and CIED team
alike will minimize the risk for the pacemaker patient. It is my sincere hope that the
recommendations I have set forth will result in physicians initiating protocols for
their own hospitals and databases to track performance outcomes.
There is a critical need for long-term data collection on radiation-exposed devices,
with the outcome data coupled to radiation modeling. Future pacemakers are
likely to provide better protection from EMI; however, unless other forms of
electrosurgery are developed that have a lower risk of EMI inference with
pacemaker, it is unlikely that concern for interactive risks will lessen.
Page 22 of 27
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1
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2,3 ,4,5
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