The Potential Impact of Intrathoracic Impedance on Defibrillation Threshold Testing in S-ICDs

Can J Cardiol. 2019 Nov;35(11):1604.e13-1604.e16. doi: 10.1016/j.cjca.2019.07.624. Epub 2019 Jul 25.

Abstract

A man with an ischemic cardiomyopathy and chronic obstructive pulmonary disease underwent subcutaneous implantable cardioverter-defibrillator (S-ICD) placement under general anesthesia. Following induction of ventricular fibrillation (VF), defibrillation testing (65J) failed, requiring external rescue. Repeat shock testing with reversed polarity (65J) failed. A third shock and external defibrillation failed (80J and 200J), followed by a second external defibrillation (200J), which did not immediately terminate VF, and a device shock 2 seconds later (80J, successful). Repeat shock testing (80J) under conscious sedation without mechanical ventilation was successful. We discuss this case of failed defibrillation testing during S-ICD placement, potentially due to lung hyperinflation, requiring double sequential defibrillation.

Publication types

  • Case Reports

MeSH terms

  • Defibrillators, Implantable*
  • Electric Countershock / instrumentation*
  • Electric Impedance
  • Electrocardiography*
  • Humans
  • Male
  • Middle Aged
  • Myocardial Ischemia / physiopathology*
  • Myocardial Ischemia / therapy
  • Thoracic Cavity / physiopathology*
  • Ventricular Fibrillation / physiopathology*
  • Ventricular Fibrillation / therapy*