Transcript ICDs reduced risk of death in heart attack survivors

Implantable Cardioverter Defibrillators &
End of Life
Anna Wilson
Cardiac Physiologist
Waikato Hospital
ICD Operations
Pacemaker and ICD Clinics
Travelling Clinics
Pacemaker and ICD patients
Taupo
132 patients = 32 ICDs
Rotorua
234 patients = 49 ICDs
Gisborne
166 patients = 65 ICDs
Thames
265 patients = 47 ICDs
New Plymouth
298 patients = 85 ICDs
Waikato patients 2,447 = 569 ICDs
ICDs = 24%
Inventor of the ICD
Michel Mirowski, M.D.
1924-1990
First Clinical Model
Short battery life
Shock only
280g
Large device
Non-programmable
Epicardial patch
electrodes
Abdominal implant
Required thoracotomy
Development
Small Device
Pectoral Implant
Usually fully
endocardial implant
Active ‘Can’
Pacemaker and ICD leads
Screw-in (active fixation)
pacemaker lead
Tined (passive fixation)
pacemaker lead
External shock coil
ICD lead (active fixation)
Implantable Cardioverter
Defibrillator (ICD)
Who Benefits from ICD Therapy
Trials
Secondary Prevention Trials: In survivors
of VT/VF arrest
Outcome  ICDs reduced the risk of
sudden death over antiarrhythmic drugs
Primary Prevention Trials: Who is at risk of
a life threatening ventricular arrhythmia?
Outcome  ICDs reduced risk of death in
heart attack survivors
Outcome  ICDs save lives in heart
failure and reduced EF
ICD – Implantable Cardioverter
Defibrillator
Primary indication (prevent SCD):
Prophylactic ICD for people at risk of a VT/VF
arrest.
(NYHA II or III heart failure, EF ≤35%)
Secondary indication:
For people that have survived a VT/VF arrest.
Patients with cardiac conditions associated
with high risk of sudden death with unexplained
syncope (likely due to ventricular arrhythmia)
ICD Therapies
ICDs deliver a range of therapies
Bradycardia pacing (it is a pacemaker)
Tachycardia pacing (ATP)
Cardiac resynchronisation therapy
Cardioversion shocks (low energy)
Defibrillation shocks (high energy)
Typical ICD settings: 1-3 zones
ATP = anti-tachycardia pacing
How many shocks?
Usually programmed to deliver 6-8 shocks
and then will stop therapy
If the rate slows and then speeds up again
this will be treated as a new episode
i.e. 6-8 shocks could be delivered again
Pacing post a 35J shock
ATP – anti tachycardia pacing
Rapid burst of pacing to try and revert
rhythm
Often several sequences are programmed
on
If successful shocks will be diverted
ATP successful and prevents a shock
SR
VT
ATP
Inappropriate shocks
Rapid AF most common cause
Sinus/atrial tachycardia (regular rhythm
with1:1 A to V relationship)
SVT
Abnormal sensing (internal or external)
Lead fracture
Medications: Important and shouldn’t be
changed without consultation with a
Cardiologist
Electromagnetic Interference
(EMI)
Strong electromagnetic fields can interfere
with ICDs.
Oversensing  Inappropriate shocks!
Base rate pacing often 40ppm with an ICD
Intrinsic rhythm (slow)
External pacing sensed as VF and shocks delivered
VVI pacing 40ppm and external pacing 70ppm – sensed as VF by ICD and shocks received
Can you touch an ICD patient
receiving a shock?
YES!
External shock uses more energy than an
internal one
Energy escaping to the surface is difficult
to detect and harmless
External Defibrillation
Do not withhold therapy for fear of
damaging ICD
ICDs are designed to withstand external
defibrillation but can be damaged
Position pads as far away (>10cm) from
ICD as possible
CPR chest compressions can be
performed as usual
Adverse psychological effects of ICD
shocks – whether appropriate or
inappropriate
Anxiety
Anger
Depression
Avoid activities
Family members also become anxious
Quality of life?
Support group
Patient run support group
Meet annually
Can meet other people with ICDs
Arrhythmia Alliance Australia
http://www.aa-international.org/au
Facebook page: Shock Absorbers
End of Life
Increase use of life saving/prolonging
devices can extend life
Cardiac disease is often progressive
Device likely to be in place at death
Duty of care to preserve the dignity of
dying
The ICD clinic needs to know that a
patient has been referred to Hospice
Remain in contact with the ICD
Clinic
Your patient may receive a shock
Shock therapy may need to be
deactivated
- Programmer
- Magnet
Your patient may die
- Device may alarm or vibrate
- Plan after death: Marae, cremation
ICD Beeping/Vibrating Alerts
An audible beep heard or vibration felt by
the patient to alert them to phone the ICD
clinic
Will occur after death if not deactivated
Distress to family members
Call the ICD clinic – the earlier the better
Pacemaker Patients at
End of Life
Nothing needs to be done
The pacemaker will not keep someone
alive or prolong the dying process
If pacemaker pulse will not initiate a heart
beat in a heart that is electrically inert and
mechanically dormant
Magnets
A magnet placed over an ICD will stop
tachycardia therapy i.e. all shocks and
ATP will be suspended
Pacing will continue
As soon as the magnet is removed
tachycardia therapy will resume
When to use a magnet with an ICD
In theatre when diathermy is being used (patient must be
monitored throughout)
If a patient is receiving inappropriate shocks
(e.g. AF, lead fracture)
If a patient is receiving appropriate therapy but patient is
conscious and haemodynamically stable (e.g. slow VT)
To stop ICD therapies in a dying patient
IF IN DOUBT DO NOT USE
check with a Cardiologist
Position of Magnet over ICD
Turning off ICDs permanently
If the patient is at end stage it may be
appropriate to have the device turned off
to prevent shocks
Needs consultation with patient, family,
Cardiologist (authorise deactivation)
Physiologist can turn off (accompanied by
senior nurse if outside of DHB) or use of a
magnet
Protocol in place