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Ultrastructural Observations in the Myocardium Beyond the Region of Acute Coagulation Necrosis Following Radiofrequency Catheter Ablation
Author(s) -
NATH SUNIL,
REDICK JAN A.,
WHAYNE JAMES G.,
HAINES DAVID E.
Publication year - 1994
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 - 10.1111/j.1540-8167.1994.tb01122.x
Subject(s) - coagulative necrosis , medicine , pathology , lesion , ablation , myocyte , necrosis , ultrastructure , catheter ablation , ventricle , electron microscope , catheter , anatomy , cardiology , radiology , physics , optics
Ultrastructural Findings After RF Ablation. Introduction: We hypothesized that myocardial injury following radiofrequency (KF) catheter ablation may extend beyond the region of acute coagulation necrosis as defined by histochemical staining. Methods and Results: Five RF lesions were created in vivo in the left ventricle of two dogs using a 4‐inm tipped ablation electrode in which RF power was adjusted to maintain an electrode‐tissue interface temperature of 85°C for 60 seconds. The lesions were bisected; one half of the lesions were stained with nitroblue tetrazolium (NBT) and the other half processed for electron microscopy. Three zones of interest were identified extending 0–3 mm, 3–6 mm, and > 6 mm from the visible pathologic lesion border. The degree of Ultrastructural injury to the myocardium was scored for each zone. Electron microscopy demonstrated the presence of significant abnormalities of the plasma membrane, mitochondria, sarcomeres, sarcoplasmic reticuluni, and gap junctions of myocytes, as well as damage to the microvasculature extending up to 6 mm beyond the pathologic lesion edge. The plasma membrane and gap junctions of myocytes and the microvasculalure appeared particularly sensitive to thermal injury, whereas the intercalated discs were relatively thermally resistant. Conclusion: RF catheter ablation results in Ultrastructural damage to the myocardium extending up to 6 mm beyond the acute pathologic RF lesion border as denned by NBT histochemical staining.