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Updated: Feb 11, 2026

A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
High defibrillation threshold with a subcutaneous implantable cardiac defibrillator due to the lead having been
Tatsuhiko Hirao1, Junichi Nitta1, Akira Sato1
1Department of Cardiovascular Medicine Japanese Red Cross Saitama Hospital Saitama Japan.
Abstract:
A 46-year-old female with a body mass index of 38.9 kg/m2 and no organic heart disease underwent a subcutaneous implantable cardioverter-defibrillator implantation for secondary prevention of sudden cardiac death in the setting of idiopathic ventricular fibrillation. Defibrillation threshold (DFT) testing during implantation detected high shock impedance and high DFT. Fluoroscopy revealed subcoil fat between the lead and the sternum, which we suspected was the reason for the high shock impedance and high DFT. We repositioned the lead to a site just above the sternum and the shock impedance and DFT improved to within the respective normal ranges.
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