Abstract 16438: Elimination of Inappropriate Subcutaneous ICD Shocks by Using a Non-Absorbable Pouch When Non-Invasive Reprogramming Fails
Introduction: Subcutaneous ICD (S-ICD) sensing algorithms and program options differ from conventional ICDs. A nominal physical shift of the generator can frequently cause change in signal-to-noise ratio and lead to inappropriate shock. Reprogramming may help eliminate some T-wave over-sensing (TWOS), however is not possible in all cases. We present a case of multiple inappropriate shocks due to TWOS from ICD generator shift that was refractory to conventional reprogramming of sensing vectors, but was successfully treated with a novel solution.
Clinical Vignette A 33-year old female patient with a known history of non-ischemic cardiomyopathy underwent S-ICD implantation for primary prevention of sudden cardiac death. Three months post-implantation, the patient suffered a total of 8 inappropriate shocks over 3 months due to TWOS; each shock occurred while bending at the waist. Multiple attempts at careful reprogramming of sensing vectors were performed, yet the patient continued to experience 4 more shocks over 3 month. Replication of the TWOS was observed with manual shifting of the S-ICD generator. Given the ongoing problem of TWOS despite conventional management, S-ICD generator revision was performed with fixation of the generator using the first-generation non-absorbable Tyrx (Aigis) pouch. The pouch was used to fix the generator in place, and was sutured to the underlying fascia using non-absorbable sutures to avoid generator shift and the resultant TWOS. Over the course of the 6 months of follow-up, no further TWOS was observed with repeated testing (including positional challenges), and no further inappropriate shocks were delivered.
Discussion Avoidance of S-ICD inappropriate shocks due to TWOS can be challenging when reprogramming the sensing vectors and sensitivity fails. Surgical fixation of the S-ICD generator using a non-absorbable pouch offers a novel solution to avoid inappropriate shocks. Potential future design modifications of the S-ICD generator to allow fixation in multiple locations may be one consideration to avoid this issue.
Author Disclosures: Z. Ahmad: None. A. Williams: None. M. Olsen: None. S. Kusne: None. W. Su: Research Grant; Modest; st jude. Research Grant; Significant; medtronic. Honoraria; Modest; st jude. Honoraria; Significant; medtronic. Other; Modest; st jude. Other; Significant; medtronic.
- © 2016 by American Heart Association, Inc.