Download Defibrillator, pacemakers and icd

Presented by: rashmi bhatt
Moderator: dr dara negi
 Principle
of defibrillator
 Defibrillator vs cardioversion
 Principle and working of pacemaker
 Anesthetic implications
 Functioning of ICD
 Anesthetic implications of ICD
 Non
synchronised delivery of energy during
any phase of the cardiac cycle
 Indications : VT, VF, cardiac arrest due to or
resulting in these
 Avoided in dysarrythmias d/t digitalis toxicity
or catecholamine induced overactivity
 Generally under induction or sedation unless
patient is hemodynamically unstable
 Hand held paddles considered better than
self adhesive electrodes
 Types
: AED, semi automated,standard with
monitor and implantable
 Positioning: anterolateral and
anteroposterior
 Anterolateral: left 4/5 ICS in midaxillary line
and right sternal edge in 2/3 ICS
 Anteroposterior: right sternal edge 2/3 ICS
and b/w tip of left scapula and spine
 Anteropost is more effective for AF and
preferred in pts with implantable devices
Energy wave forms: monophasic and biphasic
 Biphasic: truncated and rectilinear
 Biphasic is more effective and uses lesser energy
 Atrial flutter: 25-50 J; AF: 50-100 J in stable
patients
 Polymorphic VT(unstable) or VF: 200-360 J
 Monomorphic VT(stable): 100-200 J
 In pediatric patients: 0.5J/kg
 Complications: arrythmias(VF),
thromboembolism(esp in AF), myocardial
necrosis, ST elevation ( for upto 2 min), painful
skin burns,hypoxia and rarely pulm oedema. Also
injuries to the health care personnel.
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Delivery of energy is synchronised to the large R waves or
the QRS complexes
Indications: SVT, AF, atrial flutter, vent tachy, reentrant
tachy with hemodynamic instability
Synchronization is in the early part of QRS
Internal cardioversion: preceded by anticoagulation. Three
temp catheters are inserted under fluoroscopic guidance.
Two are used to deliver the shock and the third for R wave
synchronisation and pacing.
1st in distal coronary sinus, 2nd in rt atrium appendix or
lateral wall, both being connected to external
defibrillator. 3rd(quadripolar) in apex of rt ventricle,
connected to external pacemaker. Energy delivered is
5.6+-4.7 J.
Temporary or permanent
 Consists of an impulse generator and lead(s)
 Leads could be transvenous or epicardial in
position, uni, bi or mutipolar in no of electrodes
 Unipolar: more sensitive to EMI, gas interference
 Bipolar uses less energy and more resistant to
interference
 Placement could be transthoracic, transvenous
or transesophageal
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POSITION 1
Pacing
chamber(s)
POSITION 2
sensing
chamber(s)
POSITION 3 POSITION 4
response(s) programma
to sensing
bility
POSITION 5
multisite
pacing
O=none
O= none
O= none
O= none
O= none
A= atria
A= atria
I= inhibited
R= rate
modulation
A= atria
V= ventricle V= ventricle T= triggered
V= ventricle
D=dual(A+V) D=dual(A+V) D=dual(I+T)
D=dual(A+V)
 Indications:
sinus node disease, av node
disease, long QT syndrome, HOCM, DCM
 Magnet behaviour: not all devices are
sensitive
 Magnet response: IFI/ERI/EOL
 Some pacemakers carry out TMT
 Pacemaker induced tachycardia
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Pre op: optimise coexisting diseases, CXR, reprogramming
(to prevent oversensing). Spl considerations in lithotripsy,
hysteroscopy, chest/abd procedures, TURP,ECT etc.
intraop: ecg filtering disabled, avoid monopolar ESU,
equipment for pacing, defibrillation to be ready.
Post op: reprogramming and reinterrogation.
Pacemaker failure: generator failure, lead failure, failure
of capture
Failure of capture may result from increase in the
threshold for capture
Correction by magnet application, temporary pacing,
sympathomimetic drugs(epi/dopa).
 Important
to differentiate from other
thoracic devices esp pacemaker in v/o
electromagnetic interference(EMI)
 Previously placed in an abdominal pocket;
present day pectoral placement
 Can be differentiated using a CXR to examine
the RV lead system.
 Other devices could be for pain control,
thalamic stimulation to control PD, phrenic
nerve stimulation, vagus stimulation for
epilepsy, depression, heart failure and
obesity.
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Battery powered device to deliver energy in form of
shock to terminate VT/VF
Believed to be superior to drug therapy in pt with
EF<35%
Average life of 3-6 years
Principle: measures R-R interval and categorises as
normal, fast or slow.
Programmed to confirm VT/VF to avoid inappropriate
therapy(mc SVT)
Delivers 6-18 shocks per minute
Programmed to diff VT from SVT by onset, stability,
QRS width, AV synchrony and waveform
In case of slow R-R, antibradycardia pacing
Position I: Shock Position II:
Chambers(s)
Antitachycardia
Pacing
Chamber(s)
Position III:
Tachycardia
Detection
Position IV:
Antibradycardia
Pacing
Chamber(s) *
O= none
O= none
E= electrogram
A= atrium
A= atrium
H=
hemodynamic
V= ventricle
V= ventricle
V= ventricle
D= dual (A + V)
D= dual (A + V)
D= dual (A + V)
A= atrium
Tranvenous or endocardial approach
Surgical or Epicardial approach
 Indications:
vent tachy, vent fib, pts awaiting
heart transplant, long QT syndrome, brugada
syndrome, RV dysplasia.
 Prophylactic role in HOCM, post MI with
EF<30%
 Magnet behaviour: suspension pf
antitachycardia pacing. Generally no effect
on antibradycardia pacing.
 Pre
op: optimisation of coexisting conditions
checking of battery life
disable antitachycardia therapy
CXR to confirm position of RV lead
 Intra op: ecg monitoring
facility to deliver external
cardioversion/defibrillation
 Post op: reinterrogation and reenabling