Download Pacemakers and AICDs: Short Circuit of the

Pacemakers and AICDs: Short Circuit of the Electronic Heart
The expanding use of technology for acute and chronic electrical therapy of dysrhythmias is complex.
Emergency physicians must have an understanding of the various devices that utilize electrical therapy
for either rate-related control or cardioversion/defibrillation for malignant dysrhythmias. Using a casebased approach, the presenter will review the identification and management of normal and abnormal
function of implantable electronic devices.
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Discuss the normal and abnormal function of permanent pacemakers.
Discuss the normal and abnormal function of the implanted cardioverter-defibrillator.
Review potential non-electrical complications that can occur with both pacemakers and ICDs.
Describe the process by which pacemakers are interrogated.
Discuss newer cardiac pacemakers and MRI compatibility.
MO– 13
10/27/2014/ 11:30 AM– 12:20 PM
W178ab– McCormick Place
(+) No significant financial relationships to disclose
(+) Tarlan Hedayati, MD, FACEP
Assistant Professor, Associate Program Director, Department of Emergency Medicine, Cook County(Stroger)
Hospital Chicago, Illinois
10/21/2014
Pacemakers and
ICDs: Short Circuit of
the Electronic Heart
Tarlan Hedayati, MD
Associate Program Director
Assistant Professor
Cook County Hospital
Chicago, Illinois
Goals of the lecture
Review normal pacemaker / ICD function
 Recognize pacemaker / ICD complications
 Manage pacemaker / ICD malfunction

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Disclaimer

I have no financial interest in any
pharmaceutical, device, or other
healthcare companies
The Numbers
>250, 000 new permanent PM
implanted annually in the U.S.
 >750,000 worldwide
 5 million patients in the U.S. with
permanent PM

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The Numbers
16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States 1993 to 2008.Greenspon
AJ, JACC 2011 Aug 30;58(10):1001-6.
The Numbers
16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States 1993 to 2008.Greenspon
AJ, JACC 2011 Aug 30;58(10):1001-6.
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Pacemaker Indications
Sick sinus syndrome
 Complete AV block
 Cardiomyopathy (hypertrophic or dilated)
 Neurocardiogenic syncope
 Atrial fibrillation with sinus node
dysfunction

Manufacturers
 Guidant/
Boston Scientific
 1800 CARDIAC
 Medtronic
 1800 MEDTRONIC
 St. Jude
 1800 PACER QI
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Pacemaker Terminology
“PaSeR”
Position 1 Position 2 Position 3 Position 4 Position 5
Paced
Sensed
Response
Program
Function
O
O
O
O
O
A
A
T
P
P
V
V
I
M
S
D
D
D
C
D
R
Pacemaker Terminology
 VVI
- most common worldwide
 Ventricle paced
 Ventricle sensed
 Inhibition of pacing activity if normal
ventricular activity occurs
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Pacemaker Terminology
 DDD
- most common in U.S.
 Dual chamber paced
 Dual chamber sensed
 Dual response = inhibit or trigger pacing
Pacemaker Anatomy
Kusumoto, F. M. et al. JAMA 2002;287:1848-1852.
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Pocket complications
Hematoma
 Infection
 Wound dehiscence
 Erosion
 Pacemaker
migration

Ann Emerg Med. 2014 Apr;63(4):391, 403 Images in emergency
medicine. An unusual swelling at the pacemaker pocket site.
Pacemaker pocket infection caused by Stenotrophomonas maltophilia.
Aktuerk D1, Lutz M2, Luckraz H1
Pocket complications
Shapiro M et al. A Rare, Late Complication after AICD
Placement, Indian Pacing Electrophysiol. J. 2004;4(4):213216
Tex Heart Inst J. 2012;39(1):156-7.
Total extrusion of a normally functioning
pacemaker. Yuksel S1, Demir S, Sahin M.
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Infection Rates
16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States 1993 to
2008.Greenspon AJ, JACC 2011 Aug 30;58(10):1001-6.
Sohail, M. R. et al. J Am Coll Cardiol 2007;49:1851-1859
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Lead Complications
Hemothorax
 Pneumothorax
 Venous
thrombosis
 Lead infection

Dislodged lead
 Electrode
penetration
 Perforation
 Exit block

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Cardiac Resynchronization
Therapy
Biventricular pacing
 Synchronized pacing of

 Right atrium
 Right ventricle
 Lateral wall of left ventricle

CRT vs medical therapy
 30% decreased hospitalization with CRT
 24-36% mortality benefit with CRT
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On the horizon
The Nanostim leadless pacemaker by
SJM (VVI)
 First US implant in Feb 2014 at Mt.
Sinai in NYC

On the horizon
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“LEADLESS” studies

Initial results from EU LEADLESS study
 Prospective, single-arm study
 Primary endpoint is complication rate at 90d
○ 94% (31/33)

U.S. study
 Goal to enroll 670 pts
 50 US sites
 Primary endpoint is complication rate at 6m
Paced ECG: What the heck
am I looking at here?
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Electrocardiogram
Rate: 60-100 bpm
 Rhythm: Paced atrium

 Atrial spikes precede P-wave
 P-wave has a normal morphology
Chan et al. Emergency medicine clinics of North America. 2006: 179-194
Electrocardiogram

Rhythm: Paced ventricle
 Ventricular spike precedes QRS
complex
 QRS complex has a LBBB morphology
Chan et al. Emergency medicine clinics of North America. 2006: 179-194
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Electrocardiogram
Axis: Left
 ST segment

 “Appropriate discordance”

T wave
 hyperacute or inverted
Pacemaker Malfunction
Failure to pace
 Failure to capture
 Failure to sense

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Failure to pace
 Definition:
the pacemaker fails to
deliver a stimulus to the heart
 EKG: no pacer spikes
Failure to pace
Oversensing - most common cause
 Pseudomalfunction
 Electromagnetic interference
 Component/battery failure
 Lead problem

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Magnet
Magnet

Reverts the pacemaker to
asynchronous mode = turns the
sensing function off
DDD
Chan et al. Emergency medicine clinics of North America. 2006:
179-194
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Failure to pace
Pacing
with
magnet?
+
Oversensing,
EMI
No pacer spikes
present?
Native rhythm
present?
+
Slow
Fast or normal
Rate?
Pseudomalfunction
Mechanical
pacemaker
failure
Failure to capture
 Definition:
the pacemaker delivers
a stimulus but it fails to result in or
“capture” myocardial
depolarization
 EKG: pacer spike without
subsequent P-wave or QRS
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Failure to capture
Lead dislodgement
 Lead fracture
 Battery depletion






Exit block
Acute MI
Metabolic disturbance
Medications
External defibrillation
Pacemaker problem
Myocardial problem
Failure to capture
?
?
?
Cardall TY et al. J Emerg Med. 1999 Jul-Aug;17(4):697-709.
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Failure to capture
Pacer spikes
present
+
-
Capture
present?
-
-
CXR
Labs
Medications
Interrogate
pacemaker
Lead
problem
Elevated pacing
threshold
Mechanical
failure
Twiddler’s syndrome
Patients disrupt pacemaker leads by
manipulating or “twiddling” the generator
 EKG: Failure to pace or capture
 Children and thin women
 Diagnosis: CXR
 Rx=surgery

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Failure to sense
 Also
known as undersensing
 Definition: pacemaker fails to detect,
or sense, native cardiac activity and
generates inappropriate pacer spike
 EKG: pacer spike present despite
normal P or QRS complex
Failure to sense
Lead problem
 Battery end of life
 Intracardiac signal
occurs in PM
refractory period

Intracardiac signal
changes
 Metabolic/Electrol
yte
 Defibrillation

MAGNET!
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Failure to sense - atrium
Chan et al. Emergency medicine clinics of North America. 2006:
179-194
Failure to sense - ventricle
Chan et al. Emergency medicine clinics of North America. 2006:
179-194
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Failure to sense
Pacer spikes
present
+
-
CXR
Capture
present?
+
Is pacing
appropriate?
-
-
Labs
Medications
Interrogate
pacemaker
Pacemaker syndrome
Usually occurs in single-chambered
pacemakers
 Due to loss of AV synchrony, or “atrial
kick”

 decreased CO
 decreased BP
 increased atrial pressures
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Pacemaker syndrome






Fatigue or
weakness
Headache
Jaw pain
Neck pulsations
Syncope
Confusion
Hypotension
 Heart failure
 Canon a waves
 Drop in BP > 20
mmHg when going
from native rhythm
to paced rhythm

Pacemaker syndrome
ED treatment: Supportive
 Disposition: Depends on the patient
and cardiologist
 Definitive treatment: Dual-chamber
pacemaker

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PMT
Occurs in dual-chambered pacemakers
 Reentrant tachycardia
 Rate cannot exceed PM upper limit
 Usually precipitated by a PVC or removal
of a magnet

Chan et al. Emergency medicine clinics of North America. 2006: 179194
PMT

ED treatment
 Vagal maneuvers
 Precordial thump
 Adenosine
 Magnet

Definitive treatment: Reprogramming
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Runaway Pacemaker
True pacemaker malfunction
 True medical emergency
 Inappropriately rapid discharges that
can lead to VT or VF

PMT
Rate limited by
programmed
upper limit
 Magnet will stop
dysrhythmia
 ED Rx= magnet

Runaway PM
Rate is higher than
programmed upper
limit
 Magnet has little
effect
 Rx = cut the wires

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When to use the magnet
Symptomatic bradycardia and no
pacemaker activity on ECG
 Asystole

 no spikes: component or battery failure
 slow spikes: battery depletion
 normal spikes: oversensing

Pacemaker-mediated tachycardia
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Case #1
HPI: 25 year old male with a history of WPW
c/o being “shocked” by his ICD while
playing soccer
 PMHx: WPW with episode of sustained VT 1
year ago
 PSHx: Failed ablation 1 year ago, ICD
placement 1 year ago
 Meds: Amiodarone

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Case #2
HPI: 69 yo man with c/o 3 ICD “shocks” in
the last 10 minutes. Denies any preceding
chest pain, SOB, lightheadedness,
palpitations
 PMHx: CAD s/p MI x 5, HTN,
Hyperlipidemia, Paroxysmal atrial fibrillation
 PSHx: CABG x 4v-1988, PCI-2001, ICD2001
 Meds: ASA, clopidogrel, BB, ACE-I, statin

What is an ICD?
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ICD Indications

Primary prevention
 Structural heart disease at high risk for VT/VF
 History of MI and LV dysfunction
 DCM and LV dysfunction

Secondary prevention
 Sudden cardiac death due to VT/VF
 Syncope with inducible VT
 Structural heart disease and sustained VT
ICD Function

Sense and detect
 “Sudden onset”
 “Rate stability”

Terminate VT or VF
 Anti-tachycardic pacing
 Cardiovert/Defibrillate

Pace bradycardia
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History
Why does the patient have an ICD?
 How many shocks were delivered?
 What was the patient doing?
 Any preceding symptoms?
 Medications?

Initial Orders
 IV
access
 Pulse oximetry
 Cardiac monitor
 Apply external defibrillator pads
 Magnet to the bedside
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Magnet
Stops VT/VF sensing and detection
 Stops VT/VF therapy

 No ATP
 NO CARDIOVERSION
 NO DEFIBRILLATION
Pacing for bradycardia remains intact!
Magnet
 Use
the magnet if the patient:
 Receives inappropriate shock in ED
 Needs external defib/cardioversion in ED
 ICD
will emit a continuous tone when
the magnet is used in Medtronic and
Boston Scientific ICDs
 Be prepared to externally defibrillate
or cardiovert the patient!
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More Initial Orders
 Electrocardiogram
 Chest
radiograph
 Basic laboratory studies
 BMP, Calcium, Magnesium,
Phosphate, Cardiac enzymes,
Drug levels
 Determine
ICD manufacturer
Inappropriate
•VT/VF
Appropriate
•SVT
•Oversensing
•ICD malfunction
•EMI
Phantom
Defibrillate
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Interrogation
Interrogation - WiFi!
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Cardiac monitor
Ongoing arrhythmia?
YES
NO
NO
Multiple shocks
•ACLS
•Consider magnet
ICD Interrogation
Inappropriate
Single shock
Discuss with patient’s
cardiologist
Appropriate
Discharge home
•SVT: Treat, Admit
•Oversensing: Admit
•ICD lead malfunction:
Admit
•Admit
•Rule out reversible
causes
•Consider drug therapy
Case #1
HPI: 25 year old male with a history of
WPW c/o being “shocked” by his ICD
while playing soccer
 Meds: Amiodarone
 Disposition:

 Case discussed with his cardiologist
 Patient discharged home!
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Case #2
HPI: 69 yo man with c/o 3 ICD “shocks”
in the last 10 minutes. Denies any
preceding chest pain, SOB,
lightheadedness, palpitations
 PMHx: CAD s/p MI x 5, HTN,
Hyperlipidemia, Paroxysmal atrial
fibrillation

Case #2
Labs drawn and sent
 Patient placed on a cardiac monitor
 ICD delivers a “shock” to the patient
 VBG returns

 K=2.1

ICD interrogated
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Interrogation
Practical tips
Wear gloves!
 Don’t put external pads over the PM/ICD!
 Need a central line? Femoral!
 PM/ICDs don’t need antibiotic prophylaxis.
 Some PM/ICD models delete data after
download—SAVE PRINT-OUTS!

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Practical tips
Use non-depolarizing paralytic agents!
 Obese patients may need 2 magnets!
 Just because you removed the magnet
doesn’t mean the ICD works!
 Turn off the cardiac monitor after you
“pronounce” the patient!
 Think about turning off the ICD after you
“pronounce” the patient!

Thank you!
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