Document Detail

Disparity in left ventricular stimulation among different pacing configurations in cardiac resynchronization therapy.
MedLine Citation:
PMID:  22199009     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Cardiac resynchronization therapy (CRT) demands high energy utilization due to continuous biventricular pacing. Current technology allows 6 pacing configurations for a bipolar left ventricular (LV) lead. Understanding the energy requirements for each configuration will allow optimization of pacing output.
METHODS AND RESULTS: Pacing impedance, LV voltage threshold at 1.5 ms (rheobase) and 0.4 ms and chronaxie were obtained in 6 LV configurations in 49 consecutive patients undergoing CRT implantation or replacement. Strength-duration curves were derived using the Lapicque formula. Pacing impedances and voltage thresholds at 1.5 and 0.4 ms, calculated minimum threshold energy at chronaxie, current drain, energy thresholds at 0.4 ms, and strength-duration curves were statistically different between LV configurations (P<0.05). The lowest threshold energy requirements were found in Tip→right ventricular (RV) coil and Tip→Can configuration. Energy strength-duration curves involving the ring as the cathode (Ring→RV, Ring→Can, and Ring→Tip) had the highest LV thresholds. The pacing configuration with the lowest energy threshold correlated 89% of the time with the lowest voltage threshold at 0.4 ms. The probability to reach LV thresholds <1.5 V at 0.4 ms was increased from 51% with 2 LV configurations to 67% with 6 LV configurations.
CONCLUSIONS: Pacing impedance, LV thresholds, minimum threshold energy at chronaxie, current drain, voltage, and energy strength-duration curves were statistically different between LV pacing configurations. LV pacing configuration with the lowest voltage threshold does not always reflects the lowest energy threshold, particularly in the presence of a low impedance configuration. The availability of 6 LV configurations increases the probability of optimizing LV pacing output.
Jose F Huizar; Karoly Kaszala; Jayanthi Koneru; Marcin Kowalski; Leroy R Thacker; Mark A Wood; Kenneth A Ellenbogen
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural     Date:  2011-12-22
Journal Detail:
Title:  Circulation. Arrhythmia and electrophysiology     Volume:  5     ISSN:  1941-3084     ISO Abbreviation:  Circ Arrhythm Electrophysiol     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-02-15     Completed Date:  2012-04-17     Revised Date:  2013-03-08    
Medline Journal Info:
Nlm Unique ID:  101474365     Medline TA:  Circ Arrhythm Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  140-6     Citation Subset:  IM    
McGuire VA Medical Center and Virginia Commonwealth University/Pauley Heart Center, Richmond, VA 23249, USA.
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MeSH Terms
Cardiac Pacing, Artificial / methods*
Follow-Up Studies
Heart Failure / complications,  physiopathology,  therapy*
Heart Ventricles / physiopathology*
Middle Aged
Prospective Studies
Treatment Outcome
Ventricular Dysfunction, Left / complications,  physiopathology,  therapy*
Grant Support

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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