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: J; AF: J in stable patients  Polymorphic VT(unstable) or VF: J  Monomorphic VT(stable): 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.

 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.  1 st in distal coronary sinus, 2 nd in rt atrium appendix or lateral wall, both being connected to external defibrillator. 3 rd (quadripolar) in apex of rt ventricle, connected to external pacemaker. Energy delivered is 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

POSITION 1 Pacing chamber(s) POSITION 2 sensing chamber(s) POSITION 3 response(s) to sensing POSITION 4 programma bility POSITION 5 multisite pacing O=none A= atria I= inhibitedR= rate modulation A= atria V= ventricle T= triggeredV= ventricle 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

 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.

 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 Chambers(s) Position II: Antitachycardia Pacing Chamber(s) Position III: Tachycardia Detection Position IV: Antibradycardia Pacing Chamber(s) * O= none E= electrogram A= atrium H= hemodynamic A= atrium V= ventricle D= dual (A + V)

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