Michael Lloyd1, Dwight Reynolds2, Todd Sheldon3, Kurt Stromberg3, J Harrison Hudnall3, Wade M Demmer3, Razali Omar4, Philippe Ritter5, John Hummel6, Lluís Mont7, Clemens Steinwender8, Gabor Z Duray9. 1. Emory University Hospital, Atlanta, Georgia. Electronic address: mlloyd2@emory.edu. 2. Cardiovascular Section, University of Oklahoma Health Sciences Center, OU Medical Center, Oklahoma City, Oklahoma. 3. Medtronic, plc, Mounds View, Minnesota. 4. Electrophysiology and Pacing Unit, National Heart Institute, Kuala Lumpur, Malaysia. 5. Hôpital Cardiologique du Haut-Lévêque, CHU Bordeaux, Université Bordeaux, IHU LIRYC, Bordeaux, France. 6. Ohio State University, Columbus, Ohio. 7. Hospital Clínic, Universitat de Barcelona, Catalonia, Spain. 8. Department of Cardiology, Johannes Kepler University Hospital Linz, Linz, Austria. 9. Clinical Electrophysiology Department of Cardiology, Medical Centre, Hungarian Defence Forces, Budapest, Hungary.
Abstract
BACKGROUND: The Micra transcatheter pacemaker was designed to have similar functionality to conventional transvenous VVIR pacing systems. It provides rate adaptive pacing using a programmable 3-axis accelerometer designed to detect patient activity in the presence of cardiac motion. OBJECTIVE: The purpose of this study was to evaluate the system's performance during treadmill tests to maximum exertion in a subset of patients within the Micra Transcatheter Pacing Study. METHODS: Patients underwent treadmill testing at 3 or 6 months postimplant with algorithm programming at physician discretion. Normalized sensor rate (SenR) relative to the programmed upper sensor rate was modeled as a function of normalized workload in metabolic equivalents (METS) relative to maximum METS achieved during the test. A normalized METS and SenR were determined at the end of each 1-minute treadmill stage. The proportionality of SenR to workload was evaluated by comparing the slope from this relationship to the prospectively defined tolerance margin (0.65-1.35). RESULTS: A total of 69 treadmill tests were attempted by 42 patients at 3 and 6 months postimplant. Thirty tests from 20 patients who completed ≥4 stages with an average slope of 0.86 (90% confidence interval 0.77-0.96) confirmed proportionality to workload. On an individual test basis, 25 of 30 point estimates (83.3%) had a normalized slope within the defined tolerance range (range 0.46-1.08). CONCLUSION: Accelerometer-based rate adaptive pacing was proportional to workload, thus confirming rate adaptive pacing commensurate to workload is achievable with an entirely intracardiac pacing system.
BACKGROUND: The Micra transcatheter pacemaker was designed to have similar functionality to conventional transvenous VVIR pacing systems. It provides rate adaptive pacing using a programmable 3-axis accelerometer designed to detect patient activity in the presence of cardiac motion. OBJECTIVE: The purpose of this study was to evaluate the system's performance during treadmill tests to maximum exertion in a subset of patients within the Micra Transcatheter Pacing Study. METHODS:Patients underwent treadmill testing at 3 or 6 months postimplant with algorithm programming at physician discretion. Normalized sensor rate (SenR) relative to the programmed upper sensor rate was modeled as a function of normalized workload in metabolic equivalents (METS) relative to maximum METS achieved during the test. A normalized METS and SenR were determined at the end of each 1-minute treadmill stage. The proportionality of SenR to workload was evaluated by comparing the slope from this relationship to the prospectively defined tolerance margin (0.65-1.35). RESULTS: A total of 69 treadmill tests were attempted by 42 patients at 3 and 6 months postimplant. Thirty tests from 20 patients who completed ≥4 stages with an average slope of 0.86 (90% confidence interval 0.77-0.96) confirmed proportionality to workload. On an individual test basis, 25 of 30 point estimates (83.3%) had a normalized slope within the defined tolerance range (range 0.46-1.08). CONCLUSION: Accelerometer-based rate adaptive pacing was proportional to workload, thus confirming rate adaptive pacing commensurate to workload is achievable with an entirely intracardiac pacing system.
Authors: Clemens Steinwender; Hermann Blessberger; Daniel Kiblböck; Karim Saleh; Jürgen Kammler Journal: Herzschrittmacherther Elektrophysiol Date: 2018-11-19
Authors: M P Powell; J Anso; R Gilron; N R Provenza; A B Allawala; D D Sliva; K R Bijanki; D Oswalt; J Adkinson; N Pouratian; S A Sheth; W K Goodman; S R Jones; P A Starr; D A Borton Journal: J Neural Eng Date: 2021-02-05 Impact factor: 5.379
Authors: John E Fleming; Vaclav Kremen; Ro'ee Gilron; Nicholas M Gregg; Mayela Zamora; Derk-Jan Dijk; Philip A Starr; Gregory A Worrell; Simon Little; Timothy J Denison Journal: iScience Date: 2022-03-04