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Background: Four cases of inappropriate shock due to residual air in tissues after recent subcutaneous implantable cardiac defibrillator (S-ICD) implant have been reported. Yet there is little awareness of this acute complication.
Case Presentation: A 55 year-old man with hypertrophic cardiomyopathy and ventricular tachycardia underwent a S-ICD (Boston Scientific) implant. During the procedure VF was induced and appropriately sensed and defibrillated by the device. The patient received a shock 6 hours post-implantation. Device interrogation revealed oversensing in the proximal vector (left panel). An over-penetrated chest x-ray showed air around the subxiphoid node of the S-ICD lead (right panel). The device was programmed to sense an alternate vector and the patient had no additional shocks in follow-up. A repeat x-ray at 2 weeks showed resolution of air.
Discussion: After discussion with the Boston Scientific S-ICD technical group, we recommend:
1. During implantation, limiting blunt finger dissection and relying on the tunneling tool to reduce subcutaneous air.
2. Flushing the incisions with saline, and “burping” the incisions to expel air before closure.
3. Routinely obtaining over-penetrated chest films post-implantation to detect subcutaneous air.
4. Programming to an alternate vector if air is seen.
5. Recognizing QRS blunting and baseline shift on the device electrogram as the characteristic air induced artifact. This knowledge may prevent unnecessary pocket exploration.
Poster Hall, Hall C
Sunday, March 19, 2017, 9:45 a.m.-10:30 a.m.
Session Title: Arrhythmias and Clinical EP: Devices 4
Abstract Category: 5. Arrhythmias and Clinical EP: Devices
Presentation Number: 1278-071
- 2017 American College of Cardiology Foundation