Ba Maguette, Fornés Paul, Nutu Ovidiu, Latrémouille Christian, Carpentier Alain, Chachques Juan C
Laboratoire des recherches biochirurgicales (LRB), hôpital Broussais-HEGP, université Paris-5, France.
Arch Cardiovasc Dis. 2008 Nov-Dec;101(11-12):763-8. doi: 10.1016/j.acvd.2008.07.004. Epub 2008 Nov 18.
Atrial fibrillation is the most frequent form of cardiac arrhythmia. Its surgical management has improved in recent years with major advances in our knowledge of the underlying pathogenic mechanisms. This has led to simpler therapeutic strategies such as epicardial ablation. The aim of this comparative experimental study was to evaluate the efficacy of this treatment, achieved with either bipolar radiofrequency or cryoablation.
Twelve sheep were used. After left thoracotomy, epicardial ablation of the junction between the left pulmonary veins and the left atrium was achieved by means of bipolar radiofrequency in group A (n=6) and by cryoablation in group B (n=6). Electrical stimulation thresholds were determined before and after ablation. Four weeks after ablation, sheep were killed for pathologic studies.
The mean stimulation threshold was 3.5+/-0.6 mA before ablation and 15.6+/-5.6 mA after ablation. The difference was significant in both groups, showing that effective conduction blockade was obtained with the two ablation methods. Histologic studies after radiofrequency and cryoablation showed limited coagulation necrosis and cellular rarefaction, respecting the supportive tissue.
Both methods of surgical ablation by the epicardial route yielded effective electrical isolation of the pulmonary vein junction with the left atrium. This conduction blockade was due to limited coagulation necrosis with myocyte rarefaction, of similar extents in the two procedures. Standardization and refinement of this technique could extend the treatment indications for atrial fibrillation associated with other cardiac disorders that require surgical treatment without opening the left atrium.
心房颤动是最常见的心律失常形式。近年来，随着我们对潜在致病机制认识的重大进展，其外科治疗有了改善。这导致了更简单的治疗策略，如心外膜消融。本比较实验研究的目的是评估通过双极射频或冷冻消融实现的这种治疗的疗效。
使用12只绵羊。在左胸切开术后，A组（n = 6）通过双极射频实现左肺静脉与左心房交界处的心外膜消融，B组（n = 6）通过冷冻消融实现。在消融前后测定电刺激阈值。消融四周后，处死绵羊进行病理学研究。
消融前平均刺激阈值为3.5±0.6 mA，消融后为15.6±5.6 mA。两组差异均显著，表明两种消融方法均获得了有效的传导阻滞。射频和冷冻消融后的组织学研究显示凝固性坏死和细胞稀疏有限，保留了支持组织。
两种心外膜途径的外科消融方法均有效地实现了肺静脉与左心房交界处的电隔离。这种传导阻滞是由于凝固性坏死和心肌细胞稀疏有限，两种手术中程度相似。该技术的标准化和完善可扩大与其他需要手术治疗且无需打开左心房的心脏疾病相关的心房颤动的治疗适应症。
