Download Keeping the Beat

Need to Know: Implantable
Devices
Carolyn Brown RN, MN, CCRN
Education Coordinator
Emory Healthcare
Atlanta, Georgia
Disclosure Statement
I have no relationships to disclose.
Objectives
Discuss the most current method of
device implantation
Describe indications for device
therapy in the cardiac patient
Manage troubleshooting in patients
with an ICD or pacemaker.
Address patient education and
precautions.
Device Therapy
Pacemaker
ICD
Pacemaker/ICD
Cardiac Resynchronization Therapy
(biventricular pacemaker)
Biventricular Pacemaker/ICD
Pacemakers for slow
symptomatic rhythms
Slow rhythms that require
pacing
DDD -100% AV Pacing
Rate Responsive Pacers
Vary the rate of pacing according
to the patient’s physiologic need
Pacemakers
All have a set rate of pacing =
basic rate
Magnet rate = fixed or non demand
pacing at a set rate
Pacemaker Terms
Rate
Output
Sensitivity
Fire
Capture
Intrinsic rhythm
Pacer Responses
Mode of response
–Inhibit = stops pacing when the
patient’s HR > set rate
–Trigger = pacing initiated by an
event
Cardiac Resynchronization
Therapy Biventricular Pacing
Left Ventricular Remodeling
Relatively normal
chamber size
and geometry
Cohn JN, et al. J Am Coll Cardiol. 2000;35:569-582.
Remodeled
ventricle
Electrical Conduction System
Consequences of Remodeling
Globular shape of the
ventricles
Distortion of the mitral and
tricuspid valves
Results in MR and TR
– Increased workload and EDV
The Dynamics of Heart Failure
Heart failure and abnormal
enlargement of the heart
–Mitral and tricuspid regurg
–Development of LBBB
Results in “dis-synchrony” of
ventricular ejection from the right
and left heart
Cardiac Veins
Biventricular Pacing Reduces QRS
Duration
-------Therapy OFF---------------Therapy ON---------
Lead V3
QRS=160 ms
QRS=120 ms
Case Presentation
69yo woman with VF arrest, ICD implanted
Idiopathic Cardiomyopathy, LVEF 20%,
QRS 180ms
5 years later: Progressive CHF, NYHA
Class III, Spironolactone 50mg QD,
furosemide 160 BID Zaroxolyn PRN, dig,
coreg, zestril, amio, etc.
ICD upgraded to BiV pacing DDD ICD
Case Presentation
3 months later - unscheduled clinic visit for
dizziness: BP 66/50, orthostatic, wgt. loss
10lbs
Diuretic dose progressively reduced during
subsequent clinic visits over the next
8mos
Improving functional status and exercise
capacity with EF 35 - 40%
Off zaroxolyn and spironolactone,
furosemide dose reduced to 40mg prn
Pt walking up to 2miles daily.
Internal Cardioverter
Defibrillators (ICDs)
Fast rhythms that require cardioversion
or defibrillation
(Ventricular Tachycardia)
Rhythms that require defibrillation
(Ventricular Fibrillation)
In the beginning….
Dr. Michael Mirowski identified
need in 1960’s
–Sudden cardiac death syndrome
AICD vs ICD
A History of Internal Cardioverter
Defibrillators
The First Generation
– A shock box only
– No programmable shocks
– No back-up pacing
A History of Internal Cardioverter
Defibrillators
The Second Generation
– Programmable shock
– Back-up VVI pacing
A History of Internal Cardioverter
Defibrillators
The Third Generation
Tiered Therapy
– Anti-tachycardia Pacing
– Cardioversion
– Programmable shock
– Back-up VVI pacing
ICD with leadwire
ICD Implantation with Lead Wire
Patient Selection
LF EF < 40 % (systolic HF)
Previous Sudden Cardiac Death
Unexplained syncope likely due to VF
Previous STEMI (especially Anterior Wall
Myocardial Infarction)
History of sustained VT
ICD Therapies
Anti-tachycardia pacing
Cardioversion
Defibrillation
Back-up (post shock) pacing
Anti-Tachycardia Pacing
Suitability for ATP
– EP-proven return to SR with ATP
– VT < 170 beats per minute
– Monomorphic VT
Ventricular Tachycardia
converted with ATP
Anti-Tachycardia Pacing
Advantages
– Quick treatment delivery
– Low energy use
– Painless treatment of VT
– Well-tolerated by patient
Anti-Tachycardia Pacing
Disadvantages
– Ineffective in Polymorphic VT or VF
– Ineffective for VT at rates > 180 or so
– Requires Defibrillation backup
– May accelerate VT to VF
Cardioversion
Synchronized shock at 2 – 34 joules up to
a certain number of attempts
VT converted with cardioversion
Ventricular Fibrillation with
defibrillation shock
VT (rate of 250) with defibrillation
VT with cardioversion shock
and back-up pacing
Magnet Maneuvers
Magnets placed over the generator will
deactivate the ICD ATP/Defibrillation
Once the magnet is removed, the device
will resume previous settings and function
Troubleshooting ICDs
Effects of Drug Therapy = Rate
of rhythm too slow
ICD therapy based on HR
If rhythm is slower than cut-off rate,
device will not fire.
Plan to reprogram at a lower cut-off
rate.
Failure of Shocks to Convert
Cardiac scarring may effect success
ICD malfunction
Nursing Implications:
– Prepare for immediate external
defibrillation
– Do not be afraid to “harm” the ICD!
Inappropriate Shocks
Potential Sensing
– (? double counting)
Fast rhythms that are not VT (Afib)
Intervention:
– Prepare to de-activate the device until MD
can assess program features
– Use the magnet to stop shocks!
Failure to Shock
Rate of rhythm too low
ICD may be off or inactive
Dysrhythmia may be too short
Magnetic interference
Sensing lead failure
Device will need to be checked for
proper functioning
VT with ATP causing VF
Appropriate Excessive Shocks
Increased episodes of VT/VF
Medication therapy causing increased
VT/VF
Nursing Implications
– Move to ICU
– Turn device off (magnet)
– Start IV meds (amiodarone)
– Sedation
Patient Education
What to do in case of a shock
Describe shock sensation
Device follow-up
Potential changes in medications
Avoid strong magnetic fields
Driving implications
Lifestyle changes
Emotional & Social Concerns
Anxiety and fear of shocks
Social support/family support
Loss of independence
Fear of sex or other activities
Question
Anti-tachycardia Pacing (ATP) has been shown to be
successful in the following ICD patient situations:
A.
Polymorphic VT at rates between190 to 250
B.
Inducible VFib
C.
Monomorphic VT < 170 beats/minute
D.
Non-inducible tachy-dysrhythmias
Answer: C
Question
The programmed criteria that third & fourth generation
defibrillators (ICD) use to decide when to initiate treatment
is:
A.
Body temperature
B.
Morphology of the QRS complex
C.
Level of consciousness
D.
Heart rate
Answer: D
Question
The patient with an ICD should seek emergency attention
if:
A.
More than one shock felt in 24 hours
B.
The device has not fired in two days
C.
The ATP mode is used more than 3 times/day
D.
A beep sounds near electromagnetic field
Answer: A
Question
True or False
The purpose of Cardiac Resynchronization
Therapy is to enhance cardiac output by
stimulating both ventricles simultaneously.
Answer: True