Initial Experience with Intercostal Insertion of an Extravascular ICD Lead Compatible with Existing Pulse Generators

Objectives This study assessed safety and feasibility of a novel extravascular (EV) implantable cardioverter-defibrillator (ICD) lead when inserted anteriorly through a rib space and connected to various commercially available ICD pulse generators (PGs) placed in either a left mid-axillary or left pectoral pocket. Background Currently available or investigational, EV-ICDs include a subcutaneous or subxiphoid lead connected to customized EV-ICD PGs. This novel EV-ICD (AtaCor Medical, Inc, San Clemente, CA) employs a unique intercostal implant technique and is designed to function with commercial DF-4 ICD PGs. Methods In this non-randomized, single-center, acute study, 36 de novo or replacement transvenous (TV) ICD patients enrolled to receive a concomitant EV-ICD lead inserted through an intercostal space along the left parasternal margin. EV-ICD leads were connected to DF-4 compatible ICD PGs positioned in either a left mid-axillary or pectoral pocket for acute sensing and defibrillation testing. Defibrillation testing started at 30 Joules (J) and stepped down in 10 J increments following conversion success and stepped up in 5 J increments following conversion failure. Results Successful acute defibrillation using ≤ 35 J was noted in 100% of left mid-axillary PG subjects (n=27, mean 16.3 ± 8.6 J) and 83% of left pectoral PG subjects (n=6, mean 21.0 ± 8.4 J). All evaluable episodes (n=93) were automatically sensed, detected, and shocked. No serious device-related intraoperative adverse events were observed. Conclusions This first-in-human study documented safe and reliable placement of a novel extravascular ICD lead with effective sensing and defibrillation of induced ventricular fibrillation using commercial DF-4 ICD pulse generators. Condensed Abstract This study assessed feasibility of intercostal implantation of a novel extravascular implantable cardioverter-defibrillator (ICD) lead designed to function with commercial DF-4 pulse generators (PGs). Lead placement was successful in 33 of 36 attempts (94%). Acute defibrillation with ≤35 J was successful in 27 of 27 left mid-axillary PG subjects (100%) and 5 of 6 left pectoral PG subjects (83%). All evaluable episodes (n=93) were automatically detected. No serious device-related intraoperative adverse events were observed. This study demonstrates feasibility of a novel extravascular ICD lead with effective sensing and defibrillating of induced ventricular fibrillation using commercial DF-4 PGs. ### Competing Interest Statement Dr. Burke has received honoraria and research grants from Boston Scientific and AtaCor Medical as well as owns equity in AtaCor Medical. Drs. Knops and Reddy have received honoraria and research grants from Boston Scientific and Medtronic, consult for Abbott, Boston Scientific and AtaCor Medical, and hold equity in AtaCor Medical. Dr. Aasbo have received honoraria and research grants from Boston Scientific and AtaCor Medical. Mr. Husby, Mr. Marcovecchio, Mr. O'Connor, Mr. Sanghera, and Mr. Scheck are employees and shareholders of AtaCor Medical. Dr. Ebner has received research grants from AtaCor Medical. ### Clinical Trial The Parasternal Access for Shocks and Pacing with an Acutely Placed Less-Invasive Lead for EV-ICD (PASS PULL EV ICD) acute study [[NCT05099289][1]] and (Phase II) the Sensing and Defibrillation with a Commercially Available ICD Coupled With a Parasternal Extravascular Lead (SECURE EV) acute + 90-day Study [[NCT05352776][2]]. ### Funding Statement AtaCor Medical is the sponsor of these studies. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee Sanatorio Italiano, Paraguay I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data submitted in this manuscript is part of regulatory submissions and will be available online eventually. * ATP : Anti-tachycardia Pacing EV : Extravascular ICD : Implantable Cardioverter-Defibrillator ICS : Intercostal Space J : Joules PG : Pulse Generator S-ICD : Subcutaneous ICD SCD : Sudden Cardiac Death TV : Transvenous [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT05099289&atom=%2Fmedrxiv%2Fearly%2F2023%2F02%2F26%2F2023.02.21.23286264.atom [2]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT05352776&atom=%2Fmedrxiv%2Fearly%2F2023%2F02%2F26%2F2023.02.21.23286264.atom