Implantable Cardioverter Defibrillators (ICDs)


  • implantable device defibrillator +/- pacemaker (counter shock vector is from RV -> both SVC)


  • VF or sudden cardiac death survivors
  • VT-associated syncope not caused by MI or other correctable cause
  • minimally symptomatic VT with EF <35%
  • previous MI, LVEF ‘monitor only’ mode
  • dysrhythmia resistant to anti-arhythmics or if anti-arrhythmics contra-indicated


  • ideally have the cardiac technician present to enable the defibrillation function
  • have defibrillator close to hand (attach prior to surgery)
  • place pads at cardiac apex and below right clavicle


  • nurse in HDU/ ICU with resuscitation equipment close by
  • cardiac technician interrogation and reprogramming post surgery
  • check medications as they may change threshold
  • monitor for infection
  • look for lead displacement or fracture
  • check with cardiologist/technician for programming and idiosyncracies of unit
  • monitor ECG
  • have an external defibrillator available


  • no longer recommended to place magnet over AICDs — only applicable to older non-reprogrammable pacemakers
  • magnet placement turns off antiarrhythmic program but has no affect on backup pacemaker
  • all modern AICDs are reprogrammable


  • battery depletion
  • lead fracture or displacement (by surgery, defibrillation or CVL/PAC placement)
  • lead or box infection (e.g. due to bacteremia)
  • multiple shocks due to algorithm error, sensing failure, oversensing of physiological signals and lead failure
  • EMF interference from shaver, TV remote, MRI and also possible
  • ICD may be  switched off intra-operatively because of interference from diathermy (need to turn back on!)
  • threshold may be changed by medications

References and Links

  • Aguilera AL, Volokhina YV, Fisher KL. Radiography of cardiac conduction devices: a comprehensive review. Radiographics. 2011 Oct;31(6):1669-82. doi: 10.1148/rg.316115529. PubMed PMID: 21997988.
  • Atlee JL, Bernstein AD. Cardiac rhythm management devices (part I): indications, device selection, and function. Anesthesiology. 2001 Nov;95(5):1265-80. PMID: 11684999.
  • Atlee JL, Bernstein AD. Cardiac rhythm management devices (part II): perioperative management. Anesthesiology. 2001 Dec;95(6):1492-506. PMID: 11748411.

FOAM and web resources


CCC 700 6

Critical Care


Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.