Holm M, Johansson R, Smideberg B, Lührs C, Olsson S B
Department of Cardiology, University Hospital, Lund, Sweden.
Europace. 1999 Oct;1(4):248-57. doi: 10.1053/eupc.1999.0054.
Epicardial mapping is a powerful tool that has enabled us to gain insight into the electrical phenomena perpetuating atrial fibrillation and has guided the design of surgical and catheter-based therapeutic strategies. However, epicardial data are acquired during abnormal physiological conditions; the patients are anaesthetized, their chests opened, dislocating the heart and exposing it to air of room temperature, and the autonomic tone is modulated due to the surgery. The effect of intra-operative conditions on atrial electrophysiological properties have not been investigated before. Thus in the present study we assessed the atrial cycle length, shown to be an index of atrial refractoriness, and the ventricular rate before and during open-heart surgery in 10 patients with chronic atrial fibrillation and an underlying heart disease.
Using a newly introduced and validated ECG method known as frequency analysis of fibrillatory ECG (FAF-ECG), the atrial cycle length and the ventricular rate were determined just before surgery. After anaesthesia and median sternotomy, epicardial mapping of the entire right atrial free wall was performed. The mean ventricular rate as well as the dominant atrial fibrillation cycle length consistently increased, the former from 71 to 92 beats x min(-1) (mean of all patients, P<0.05) and the latter from 156 to 172 ms (P<0.05).
Atrial fibrillation cycle length, an index of atrial refractoriness, is increased as an effect of anaesthesia and heart exposure during open-heart surgery in patients with chronic atrial fibrillation, implying that atrial activation might be altered, which must be considered when interpreting data from epicardial conduction analysis.
心外膜标测是一种强大的工具，使我们能够深入了解维持心房颤动的电现象，并指导了基于手术和导管的治疗策略的设计。然而，心外膜数据是在异常生理条件下获取的；患者处于麻醉状态，胸部打开，心脏移位并暴露于室温空气中，并且自主神经张力因手术而受到调节。术中条件对心房电生理特性的影响此前尚未得到研究。因此，在本研究中，我们评估了10例患有慢性心房颤动和潜在心脏病的患者在心脏直视手术前和手术期间的心房周期长度（已证明是心房不应期的一个指标）和心室率。
使用一种新引入并经过验证的心电图方法，即颤动心电图频率分析（FAF-ECG），在手术前测定心房周期长度和心室率。麻醉和正中胸骨切开术后，对整个右心房游离壁进行心外膜标测。平均心室率以及主要心房颤动周期长度持续增加，前者从71次/分钟增加到92次/分钟（所有患者的平均值，P<0.05），后者从156毫秒增加到172毫秒（P<0.05）。
在患有慢性心房颤动的患者进行心脏直视手术期间，作为心房不应期指标的心房颤动周期长度因麻醉和心脏暴露而增加，这意味着心房激活可能会改变，在解释心外膜传导分析数据时必须考虑这一点。
