“Just Put a Magnet On It”
An Update on Cardiac
Implantable Electronic Devices
Carolyn Boyle, RN, BSN, SRNA
Goldfarb School of Nursing at Barnes-Jewish
College
Objectives
• Review the perioperative implications of
Cardiac Implantable Electronic Devices
• Discuss the risks of Electromagnetic
Interference (EMI)
• Examine recommendations for preoperative
assessment and preparation, intraoperative
management, and postoperative recovery for
patients with CIED’s
Outline
•
•
•
•
•
•
Case Study
CIED Review
Magnet Mechanism
Practice Recommendations
The Future of CIED’s
Conclusions
Case Study
• 65 y.o. male with a hx of SCC of the head and neck
– Presents with flap necrosis, osteonecrosis, orocutaneous
fistula formation, & a complicated open wound
– s/p mandibulectomy, tracheostomy, bil neck dissection,
split thickness skin grafting, and G tube placement ~ 8
mos prior.
– ~2 mos prior, pt had flap and trach revision
– presenting for removal of hardware with radial and
scapular flap reconstruction
• PMH: SCC of head and neck, HTN, CHF (EF 30-40%),
AFlutter, DM, COPD, Cardiac Arrest
– Torsades arrest following cardioversion in 2012,
warranting AICD placement
Case Study con’t.
• AICD last interrogated preoperatively 2
months prior with recommendations for
magnet placement.
• Uneventful induction of anesthesia, HOB
turned 180 degrees, additional PIV’s and
arterial line placed. Magnet placed over
device and secured with 2 in silk tape.
Case Study con’t.
• Approximately 10 min after incision,
surgeon using Bovie electrocautery
while exposing the mandible
• Patient’s AICD fired
– No hemodynamic compromise
– No arrhythmias
• What happened?
Pacemakers
• Can be single chamber, dual chamber (A-V), or
multi-chamber (bi-V)
• The leads can be either monopolar or bipolar
– Bipolar is most common today – reduces the
risk of electromagnetic interference (EMI)
In 2001, standardized programming codes were
developed:
PACING
SENSING
RESPONSE
RATE
MODULATION
MULTISITE
PACING
A = Atrium
A = Atrium
I = Inhibited
R = Ratemodulating
V = Ventricle
V = Ventricle
V = Ventricle
T = Triggered
O = none
A = Atrium
D = Dual (A&V)
D = Dual (A&V)
D = Dual (I and/or
T)
D = Dual (A&V)
O = None
O = None
O = None
Internal Cardioverter
Defibrillators (ICD)
• Detect & treat ventricular arrhythmias
– Today, incorporate pacemakers in case
defibrillation results in bradycardia or asystole
• Can be single chamber (RV lead only), dual
chamber (A&V leads), or triple chamber (atrial,
RV, LV leads).
– Pre-programmed ‘zones’ based on heart rates and
chamber of origin.
– Based on rate, the device can initiate antitachycardia pacing or deliver a defibrillatory shock
Potential Perioperative
Problem: Electromagnetic
Interference (EMI)
Classic Causes:
• Surgical electrocautery
• Nerve stimulator
• Evoked potential
monitoring
• Radiofrequency
Ablation
Potential Causes:
• Fasciculations
• Shivering
• Large tidal volumes
• Lithotripsy
Pacemaker:
Inhibition of pacing due to
oversensing
Brief exposure generally not a
problem
Prolonged exposure can lead to
conversion to asynchronous
pacing mode
Defibrillator:
inappropriate defibrillation
Magnet Mechanism: The
Reed Switch
Source: Sony et al 2011
***Magnet effect on CIED is extremely variable depending on the
device, body habitus, manufacturer, programmed settings,
and battery life.
Magnet + PACEMAKER
• Usually, a magnet will convert a pacemaker to asynchronous
mode
– Device response to magnet can be programmed
– Rate depends on the manufacturer and the battery life
– Asynchronous pacing mode depends on prior settings
DDD  DOO
VVI  VOO
AAI  AOO
• Caution: Asynchronous rate may not always meet the
physiologic demands of the patient
• Upon removal, device should revert to originally programmed
pacing mode
Source: Sony et al 2011
Magnet + DEFIBRILLATOR
• Usually, a magnet will prevent
antitachycardic pacing and defibrillation
– In order to prevent oversensing of EMI
• Modern AICD’s are also pacemakers – a
magnet will not have any effect on the
pacemaker function!!
– For patients with AICD’s who are pacemaker
dependent  preoperative interrogation and
reprogramming is recommended
Source: Sony et al 2011
February, 2011
Focused Pre-Operative
Evaluation
– Presence of device
• H&P, medical record review, CXR, EKG, physical exam
– Type of device
• Manufacturer ID card, CXR, supplemental records, consult
cardiology, year placed
– Dependency on pacemaker function
• Verbal history of syncope or bradycardia requiring CIED
placement, AV node ablation, 100% paced on EKG
– Device function
• Best way: comprehensive evaluation (interrogation)
• At minimum: evaluation of EKG or rhythm strip,
discussion with patient
CXR Interpretation
CXR Interpretation
CXR Interpretation
CXR Interpretation
CXR Interpretation
Preparation is
Everything!
• Likelihood of Electromagnetic Interference (EMI)
• Need for preoperative CIED reprogramming
– Asynchronous pacing
– Suspension anti-tachyarrhythmia functions
• Suggest the use of Bipolar/ Harmonic electrocautery
• Assure presence of external pacing/ defibrillation capabilities
before, during, and after the procedure
• Evaluating the possible effect of anesthetic technique on CIED
function
– Consider positioning of the patient
EMI above
umbilicus?
From: Neelankavil et al. 2013.
YES
NO
No reprogramming
or magnet
necessary. Have
magnet available.
Pacemaker
Dependent?
YesMagnet/
reprogram to
asynch
ICD
Deactivate ICD –
magnet/
reprogram
Pacemaker
Dependent?
NoConsider reprogram/
magnet if source is
<15 cm from
generator. Have
magnet avail.
No-
Yes-
No reprogram
necessary
Reprogram to
asynch.
Intra-operative
Management
• If a magnet is placed or the device is
reprogrammed, external defibrillation
should be immediately available!
– Place pads as far away from generator as
possible
– A-P placement is preferred
Intraoperative
Management
• Monitor patient appropriately, monitor function of device,
and monitor for signs of EMI
• Assure the cautery grounding pad is positioned so that the
current pathway doesn’t cross through or near the device
– This may mean that sites other than the thigh should
be used
• Surgeon should avoid cautery near the device
• Short, intermittent bursts of cautery at the lowest possible
energy level is ideal
• Risk of EMI is much greater with monopolar than bipolar
cautery
Algorithm for Emergent
Cardioversion or Defibrillation
Observe for
appropriate
CIED response
Magnet
placed preop
Remove
Magnet!
Prepare for
external defib
or
cardioversion
Surgeon
terminates
all sources
of EMI
Device
reprogrammed
preop
Re-enable
therapies if
programmer
immediately
available
Post-Operative Care
• Continuous monitoring
• Pacing & defibrillation available
• Regardless of the anesthetic approach to
the CIED, electrocautery within 6 inches
of the device can damage to the internal
circuitry and post-operative
interrogation is recommended
• If there is any question, device should be
interrogated to assess function
Case Study Conclusion
• Electrocautery removed from the field, device
representative called to the room
– Interrogated device, confirmed defibrillation
– Unsure why magnet failed
– Manual reprogramming of defibrillator
• Surgery proceeded without further incident
• Device interrogated postoperatively and
returned to preoperative settings
The Future of CIED’s
NanostimTM Leadless PM
Subcutaneous ICD
THANK YOU!
QUESTIONS?
References
American Society of Anesthesiologists Committee on Standards and Practice Parameters. (2011). Practice advisory for the
perioperative management of patients with cardiac implantable electronic devices: Pacemakers and implantable
cardioverter-defibrillators. Anesthesiology, 114, 247-261. doi: 10.1097/ALN.0b013e3181fbe7f6
Neelankavil, J. P., Thompson, A., Mahajan, A. (2013). Managing cardiovascular implantable electronic devices (CIED’s)
during perioperative care. APSF Newsletter, 28, 31-35.
Jacob, S., Panaich, S. S., Maheshwari, R., Haddad, J. W., Padanilam, B. J., John, S. K. (2011). Clinical applications of magnets
on cardiac rhythm management devices. Europace, 13, 1222-1230. doi: 10.1093/europace/eur137
Lanzman, R. S., Winter, J., Blondin, D., Furst, G., Scherer, A., Miese, F. R., Abbara, S., Kropil, P. (2011). Where does it lead?
Imaging features of cardiovascular implantable electronic devices on chest radiograph and CT. Korean J Radiol, 12
(5), 611-619. doi: 10.3348/kjr.2011.12.5.611.
Schulman, P. M., Rozner, M. A. (2013). Use caution when applying magnets to pacemakers or defibrillators during surgery.
Anesthesia & Analgesia, 117, 422-427. doi:10.1213/ANE.0b013e31829003a1
Rooke, G. A., Bowdle, T. A. (2013). Perioperative management of pacemakers and implantable cardioverter defibrillators:
It’s not just about the magnet. Anesthesia & Analgesia, 117, 292-294. doi: 10.1213/ANE.0b013e31829799f3
Rozner, M. (2004). Pacemaker misinformation in the perioperative period: Programming around the problem. Anesthesia
& Analgesia, 99, 1582-1584. doi: 10.1213/01.ANE.0000140244.35896.D7