Related Experiment Video
Updated: Jan 6, 2026
A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
The Potential Impact of Intrathoracic Impedance on Defibrillation Threshold Testing in S-ICDs
Christopher C Cheung1, Jacob M Larsen1, Jamil Bashir1
1Heart Rhythm Services, St Paul's Hospital, University of British Columbia, Vancouver, British Columbia, Canada.
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.
