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Acute and Chronic Electrophysiologic Changes Surrounding Radiofrequency Lesions
Author(s) -
WOOD MARK A.,
FULLER ITHIEL A.
Publication year - 2002
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1046/j.1540-8167.2002.00056.x
Subject(s) - medicine , lesion , repolarization , ablation , cardiology , radiofrequency ablation , reentry , endocardium , electrophysiology , nuclear medicine , pathology
Electrophysiologic Changes Surrounding RF Lesions.Introduction: Arrhythmia recurrences may occur after acutely successful radiofrequency (RF) ablation, suggesting reversible electrophysiologic effects on myocardial tissue. The aim of this study was to examine the electrophysiologic changes occurring in myocardium surrounding acute and chronic RF lesions. Methods and Results: RF lesions (60°C for 30 sec) were produced on the epicardial left ventricular surface of 35 isolated perfused rabbit hearts. Microelectrode transmembrane action potential recordings were made at 0.25‐mm intervals along the epicardial ( n = 20 ) or intramural ( n = 6 ) aspects of the lesions for up to 3.5 mm from the lesion edge at baseline and after acute RF lesion formation. In nine hearts, chronic lesions were studied with epicardial recordings made 22 ± 13 days after RF lesion formation. In the acute hearts at 600‐msec paced cycle length, action potential duration at 50% repolarization (APD 50 ) and 90% repolarization (APD 90 ) were reduced by up to 41% and 19%, respectively, within 2.5 mm from the lesion edge ( all P < 0.05 ). Maximal action potential amplitude (APD max ) was reduced by 16% at 0.25 mm from the lesion edge ( P = 0.009 ) but dV/dt was not changed. Conduction time (CT) from the outermost recording site to the lesion edge (3.5‐mm distance) was reduced from 16 ± 3 msec at baseline to 13 ± 4 msec post ablation ( P = 0.006 ). Qualitatively similar findings occurred at 200‐msec cycle lengths. There were no changes in APD, CT, APD max , or dV/dt surrounding the chronic lesions at 22 ± 13 days after lesion formation. Conclusion: Acutely following RF energy delivery, APD, APD max , and CT are reduced in the tissue surrounding the lesion. These electrophysiologic changes resolve within 22 ± 13 days of lesion formation.