Abstract 11818: Post-shock Pacing With the Subcutaneous Implantable Cardioverter-Defibrillator (S-ICD): Results From the IDE Trial
Introduction: In the subcutaneous implantable cardioverter-defibrillator (S-ICD) system, post-shock pacing (PSP) is a programmable feature allowing the delivery of 200 mA of transthoracic demand ventricular pacing at 50 bpm for up to 30 seconds post-shock. The need for and efficacy of PSP with the S-ICD is unknown.
Methods: The S-ICD Investigational Device Exemption (IDE) trial enrolled 330 patients, 314 of whom underwent successful S-ICD implantation. At the time of implant, VT/VF was induced with a transthoracic 50Hz burst during testing and again ≥150 days later if the patient was also enrolled in a chronic conversion testing study. PSP was enabled at the discretion of the investigator. Regardless of the vector selected for VT/VF sensing, PSP sensing is based on the vector between the parasternal electrodes rather than a vector including the generator as it is part of the pacing bipole and unable to sense. Capture was defined as the presence of a QRS complex immediately after the pacing stimuli.
Results: PSP was enabled for 728 of the 733 VT/VF episodes during conversion testing. Of these, 654 were at initial implant and 74 at chronic conversion testing. In 544 episodes (74.8%), PSP was appropriately inhibited as the heart rate was >50 bpm. In 184 episodes (25.2%) there was at least one paced beat post-shock. In one episode, a single impulse of PSP was inappropriately delivered when an ectopic beat was undersensed. PSP occurred with equal frequency at acute (25.4%) and chronic (24.3%) conversion testing. In all episodes, capture was achieved when pacing was delivered. There were no pacing-induced arrhythmias, undersensing of VT/VF recurrence despite the change in sensing vector or other harm associated with PSP.
Conclusion: Transthoracic demand ventricular PSP is safely and effectively delivered by the S-ICD for up to 30 seconds in approximately one quarter of subjects for a heart rate ≤ 50 bpm immediately after an effective shock for induced VT/VF. Since shocks were delivered in the presence of deep sedation or general anesthesia, how this correlates with the need for pacing and its tolerability after shocks for spontaneous events remains unknown.
Author Disclosures: N. Verma: Honoraria; Modest; Medtronic, Inc. J.M. Prutkin: Research Grant; Modest; St. Jude, Boston Scientific. K.K. Patton: None. M.C. Burke: Research Grant; Significant; Boston Scientific. Honoraria; Significant; Boston Scientific. Consultant/Advisory Board; Significant; Boston Scientific. R. Weiss: Research Grant; Significant; Medtronic. R. Weiss: Research Grant; Significant; Medtronic, St. Jude, Boston Scientific, Biotronik, Biosense Webster. Speakers Bureau; Significant; Biotronik, Boston Scientific, Biosense Webster. Honoraria; Significant; Catheter Robotic, St. Jude, Boston Scientific, Biotronik, Biosense Webster. B.P. Knight: Research Grant; Significant; Medtronic. Speakers Bureau; Significant; Medtronic.
- © 2016 by American Heart Association, Inc.