Histopathology of intraoperatively induced linear radiofrequency ablation lesions in patients with chronic atrial fibrillation.
Eur Heart J
; 26(17): 1797-803, 2005 Sep.
Article
em En
| MEDLINE
| ID: mdl-15855195
ABSTRACT
AIMS:
Radiofrequency (RF) energy has been extensively used in ablation of arrhythmia but so far no analysis of morphological effects in human left atria has been conducted. METHODS ANDRESULTS:
We studied 59 ablation lesions from seven patients who died 2 to 22 days after open heart surgery plus intraoperative cooled-tip RF ablation to treat permanent atrial fibrillation (AF) (mean 4, 1-11 years). The ablation area was studied by macroscopy and histological analysis. RF ablation produced clearly delineated coagulation necrosis (up to a depth of 5.5 mm) bordered by an irregular zone of incomplete necrosis and fresh bleeding even 22 days post-operatively. No superficial charring, thrombotic deposition, or perforation was documented. Endocardium and subendocardium displayed oedematic loosening and microfragmentation of connective tissue fibres. Early after ablation (2-6 days), interfibrillar disseminated bleeding and necrosis without tissue removal response were found. Later after ablation (21, 22 days), mild inflammatory reaction and granulation tissue appeared. Twenty-five per cent of all studied lesions, especially in the thick region in between left pulmonary veins and mitral annulus (left atrial isthmus) (86%), were non-transmural. Nerve fibres with different degrees of thermal injury were detected in the pulmonary vein ostial region.CONCLUSION:
Intraoperative cooled-tip ablation in AF resulted in coagulation necrosis of endocardium, subendocardium, and the atrial myocardial layer to a depth of 5.5 mm bordered by an irregular zone of incomplete thermal damage. Transmurality of the lesions could only be found in 75% of intraoperatively applied lesions.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fibrilação Atrial
/
Ablação por Cateter
Limite:
Aged
/
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article