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Pretreatment of BAPTA-AM Suppresses the Genesis of Repetitive Endocardial Focal Discharges and Pacing-Induced Ventricular Arrhythmia During Global Ischemia.
MedLine Citation:
PMID:  21489030     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
BAPTA-AM and Repetitive Endocardial Focal Discharges. Introduction: In isolated rabbit hearts, repetitive endocardial focal discharges (REFDs) were consistently observed during ventricular fibrillation (VF) with prolonged (>5 minutes) global ischemia (GI). We hypothesized that BAPTA-AM, a calcium chelator, can suppress these REFDs. Methods and Results: Using a two-camera optical mapping system, we simultaneously mapped endocardial (left ventricle, LV) and epicardial (both ventricles) activations during ventricular arrhythmia with GI. In 5 hearts (protocol I), we infused Tyrode's solution (no BAPTA-AM) for ≥30 minutes before the onset of no-flow GI. In 7 additional hearts (protocol II), BAPTA-AM (20 μmol/L) was infused for ≥30 minutes before the initiation of GI. In protocol I, sustained VF (>30 seconds) was successfully induced in all 5 hearts with prolonged GI. REFDs were present in >85 % of recording time. In protocol II, however, ventricular arrhythmia was not inducible and REFDs were not observed after 5-minute GI in 5 hearts. Effects of BAPTA-AM on intracellular calcium (Ca(i) ) at the LV endocardium were also evaluated in 5 hearts (protocol III) using dual Ca(i) /membrane potential mapping. GI, both without and with BAPTA-AM pretreatment, caused a decrease of Ca(i) amplitude during S(1) pacing. However, this effect was more pronounced in the hearts with BAPTA-AM pretreatment (P < 0.001). GI, without BAPTA-AM pretreatment, caused broadening of Ca(i) transient. In contrast, GI, with BAPTA-AM pretreatment, caused narrowing of Ca(i) transient. Conclusions: BAPTA-AM pretreatment attenuates Ca(i) transient, suppressing the genesis of REFDs and pacing-induced ventricular arrhythmia during GI. These findings support the notion that Ca(i) dynamics is important in the maintenance of REFDs. (J Cardiovasc Electrophysiol, Vol. pp. 1-9).
Authors:
Tsu-Juey Wu; Shien-Fong Lin; Yu-Cheng Hsieh; Tung-Chao Lin; Jiunn-Cherng Lin; Chih-Tai Ting
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-4-13
Journal Detail:
Title:  Journal of cardiovascular electrophysiology     Volume:  -     ISSN:  1540-8167     ISO Abbreviation:  -     Publication Date:  2011 Apr 
Date Detail:
Created Date:  2011-4-14     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9010756     Medline TA:  J Cardiovasc Electrophysiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2011 Wiley Periodicals, Inc.
Affiliation:
Cardiovascular Center, Taichung Veterans General Hospital and Department of Internal Medicine, Faculty of Medicine, Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan Division of Cardiology, Cardiovascular Research Group, Institute of Medicine, Chung-Shan Medical University Hospital, Taichung, Taiwan Krannert Institute of Cardiology and the Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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