Charles D Swerdlow1, Xusheng Zhang2, Robert Sawchuk2, Saul Greenhut2, Yanina Grinberg2, Yuanzhen Liu2, Ian Crozier3, David O'Donnell4, Emily Kotschet5, Haris Haqqani6. 1. Smidt Heart Center, Cedars Sinai Medical Center, Los Angeles, California, USA. Electronic address: swerdlow@ucla.edu. 2. Medtronic plc, Mounds View, Minnesota, USA. 3. Department of Cardiology, Christchurch Hospital, Christchurch, New Zealand. 4. Department of Cardiology, The Austin Hospital, Heidelberg, Victoria, Australia. 5. Department of Cardiac Rhythm Services, Monash Medical Centre, Clayton, Victoria, Australia. 6. Department of Cardiology, Prince Charles Hospital, Brisbane, Queensland, Australia.
Abstract
OBJECTIVES: This study reports the sensing and arrhythmia detection performance of a novel extravascular (EV) implantable cardioverter-defibrillator (ICD) in a first-in-human pilot study. BACKGROUND: The EV ICD lead is implanted in the substernal space, resulting in novel sensing and detection challenges. It uses a programmable sensing profile with new or modified discrimination of oversensing and of ventricular tachycardia (VT) from supraventricular tachycardia (SVT). METHODS: Electrograms were post-processed from induced ventricular fibrillation (VF) at implant to determine virtual detection times for each programmable sensitivity and the least-sensitive safe sensitivity setting. In ambulatory patients, programmed sensitivity provided at least a twofold safety margin for detecting induced VF. Noise discrimination was stress tested, and the effects of source, posture, and lead maturation were determined on electrogram amplitude. Telemetry Holter monitors were used to quantify undersensing and oversensing. RESULTS: In 20 patients at implant, the least-sensitive safe sensitivity for VF detection ranged from 0.1 to 0.6 mV. Seventeen patients were followed up for a total of 16.6 patient-years. Electrogram amplitudes were stable over time, but there were significant differences among postures and sensing vectors. For the primary sensing vector, the weighted oversensing and undersensing rates were 1.03% and 0.40% respectively, on a beat-to-beat basis. Oversensing did not cause inappropriate therapy in patients with in situ leads. Oversensing discriminators withheld VF detection in 4 of 5 spontaneous, sustained oversensed episodes. SVT-VT discriminators correctly classified 93% of 128 sustained SVTs in monitor zones. CONCLUSIONS: In the EV ICD pilot study, oversensing did not cause inappropriate therapy during ambulatory follow-up of stable leads.
OBJECTIVES: This study reports the sensing and arrhythmia detection performance of a novel extravascular (EV) implantable cardioverter-defibrillator (ICD) in a first-in-human pilot study. BACKGROUND: The EV ICD lead is implanted in the substernal space, resulting in novel sensing and detection challenges. It uses a programmable sensing profile with new or modified discrimination of oversensing and of ventricular tachycardia (VT) from supraventricular tachycardia (SVT). METHODS: Electrograms were post-processed from induced ventricular fibrillation (VF) at implant to determine virtual detection times for each programmable sensitivity and the least-sensitive safe sensitivity setting. In ambulatory patients, programmed sensitivity provided at least a twofold safety margin for detecting induced VF. Noise discrimination was stress tested, and the effects of source, posture, and lead maturation were determined on electrogram amplitude. Telemetry Holter monitors were used to quantify undersensing and oversensing. RESULTS: In 20 patients at implant, the least-sensitive safe sensitivity for VF detection ranged from 0.1 to 0.6 mV. Seventeen patients were followed up for a total of 16.6 patient-years. Electrogram amplitudes were stable over time, but there were significant differences among postures and sensing vectors. For the primary sensing vector, the weighted oversensing and undersensing rates were 1.03% and 0.40% respectively, on a beat-to-beat basis. Oversensing did not cause inappropriate therapy in patients with in situ leads. Oversensing discriminators withheld VF detection in 4 of 5 spontaneous, sustained oversensed episodes. SVT-VT discriminators correctly classified 93% of 128 sustained SVTs in monitor zones. CONCLUSIONS: In the EV ICD pilot study, oversensing did not cause inappropriate therapy during ambulatory follow-up of stable leads.
Authors: Levente Molnár; Ian Crozier; Haris Haqqani; David O'Donnell; Emily Kotschet; Jeffrey Alison; Amy E Thompson; Varun A Bhatia; Roland Papp; Endre Zima; Ádám Jermendy; Astrid Apor; Béla Merkely Journal: Europace Date: 2022-05-03 Impact factor: 5.486
Authors: Amy E Thompson; Brett Atwater; Lucas Boersma; Ian Crozier; Gregory Engel; Paul Friedman; J Rod Gimbel; Bradley P Knight; Jaimie Manlucu; Francis Murgatroyd; David O'Donnell; Juergen Kuschyk; Paul DeGroot Journal: J Cardiovasc Electrophysiol Date: 2022-05-08 Impact factor: 2.942