Document Detail

Comparison of radiofrequency ablation in normal versus scarred myocardium.
MedLine Citation:
PMID:  16426407     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: Reentrant circuits causing ventricular tachycardia are closely associated with previously scarred myocardium. The presence of scar has been blamed for the poor success rate of radiofrequency ablation (RFA) in that context. This article investigates the in vivo effects of radiofrequency ablation in myocardium scarred from acute myocardial infarction. METHODS AND RESULTS: Anterior myocardial infarction was induced in five dogs by ligating the left anterior descending artery. The mean left ventricular ejection fraction after infarction was 38%. At a mean of 15 weeks following myocardial infarction, 50 RFA lesions were created in random order, 25 in scarred and 25 in normal myocardium using a needle electrode (21 gauge, 5 mm in length) introduced from the epicardium of the left ventricle at thoracotomy. During unipolar temperature-controlled RFA (90 degrees C for 60 seconds), intramural temperatures were measured by thermistors at distances of 1, 2, 3, 4, and 5 mm from the ablating electrode. The margins of the lesions were clearly discernible in scar at histological examination in 64% of ablations where the scarring was patchy. There were no significant differences between lesion sizes, intramural temperatures at different distances, total energy required for ablation, or mean impedance during ablation of normal versus scarred myocardium. CONCLUSIONS: Scar does not affect lesion size or intramural temperature profile during RFA if electrode size, tissue contact, and tip temperature are controlled. More radiofrequency energy is not required to maintain tip temperature at 90 degrees C in scar compared to normal myocardium.
Pramesh Kovoor; Michael P J Daly; Jim Pouliopoulos; Karen Byth; Barbara I Dewsnap; Vicki E Eipper; Teresa Yung; John F B Uther; David L Ross
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of cardiovascular electrophysiology     Volume:  17     ISSN:  1045-3873     ISO Abbreviation:  J. Cardiovasc. Electrophysiol.     Publication Date:  2006 Jan 
Date Detail:
Created Date:  2006-01-23     Completed Date:  2006-05-04     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9010756     Medline TA:  J Cardiovasc Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  80-6     Citation Subset:  IM    
Department of Cardiology, Westmead Hospital, Sydney, Australia.
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MeSH Terms
Body Temperature
Catheter Ablation / methods*
Disease Models, Animal
Hot Temperature
Myocardial Infarction / complications*,  pathology
Myocardium / pathology*
Tachycardia, Ventricular / complications,  pathology,  surgery*
Treatment Outcome

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

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