Chul-Ho Kim1, Yong-Mei Cha2, Win-Kuang Shen3, Dean J Maccarter4, Bryan J Taylor2, Bruce D Johnson2. 1. Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota. Electronic address: kim.chulho@mayo.edu. 2. Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota. 3. Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona. 4. Shape Medical Systems, Inc., Saint Paul, Minnesota.
Abstract
BACKGROUND: Cardiac resynchronization therapy (CRT) has been an important treatment for heart failure. However, it is controversial as to whether an individualized approach to altering AV and VV timing intervals would improve outcomes. Changes in respiratory patterns and gas exchange are dynamic and may be influenced by timing delays. Light exercise enhances the heart and lung interactions. Thus, in this study we investigated changes in non-invasive gas exchange by altering AV and VV timing intervals during light exercise. METHODS: Patients (n = 20, age 66 ± 9 years) performed two walking tests post-implantation. The protocol evaluated AV delays (100, 120, 140, 160 and 180 milliseconds), followed by VV delays (0, -20 and -40 milliseconds) while gas exchange was assessed. RESULTS: There was no consistent group pattern of change in gas exchange variables across AV and VV delays (p > 0.05). However, there were modest changes in these variables on an individual basis with variations in VE/VCO2 averaging 10%; O2 pulse 11% and PETCO2 5% across AV delays, and 4%, 8% and 2%, respectively, across VV delays. Delays that resulted in the most improved gas exchange differed from nominal in 17 of 20 subjects. CONCLUSION: Gas exchange measures can be improved by optimization of AV and VV delays and thus could be used to individualize the approach to CRT optimization.
BACKGROUND: Cardiac resynchronization therapy (CRT) has been an important treatment for heart failure. However, it is controversial as to whether an individualized approach to altering AV and VV timing intervals would improve outcomes. Changes in respiratory patterns and gas exchange are dynamic and may be influenced by timing delays. Light exercise enhances the heart and lung interactions. Thus, in this study we investigated changes in non-invasive gas exchange by altering AV and VV timing intervals during light exercise. METHODS:Patients (n = 20, age 66 ± 9 years) performed two walking tests post-implantation. The protocol evaluated AV delays (100, 120, 140, 160 and 180 milliseconds), followed by VV delays (0, -20 and -40 milliseconds) while gas exchange was assessed. RESULTS: There was no consistent group pattern of change in gas exchange variables across AV and VV delays (p > 0.05). However, there were modest changes in these variables on an individual basis with variations in VE/VCO2 averaging 10%; O2 pulse 11% and PETCO2 5% across AV delays, and 4%, 8% and 2%, respectively, across VV delays. Delays that resulted in the most improved gas exchange differed from nominal in 17 of 20 subjects. CONCLUSION: Gas exchange measures can be improved by optimization of AV and VV delays and thus could be used to individualize the approach to CRT optimization.
Authors: Jeroen J Bax; Gerardo Ansalone; Ole A Breithardt; Genevieve Derumeaux; Christophe Leclercq; Martin J Schalij; Peter Sogaard; Martin St John Sutton; Petros Nihoyannopoulos Journal: J Am Coll Cardiol Date: 2004-07-07 Impact factor: 24.094
Authors: Lawrence P Cahalin; Paul Chase; Ross Arena; Jonathan Myers; Daniel Bensimhon; Mary Ann Peberdy; Euan Ashley; Erin West; Daniel E Forman; Sherry Pinkstaff; Carl J Lavie; Marco Guazzi Journal: Heart Fail Rev Date: 2013-01 Impact factor: 4.214