Division of Cardiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China.
Division of Cardio-Thoracic Surgery, First Affiliated Hospital of Nanjing Medical University, Nanjing, People's Republic of China.
Heart Rhythm. 2015 Jul;12(7):1611-8. doi: 10.1016/j.hrthm.2015.03.026. Epub 2015 Mar 16.
Most postsurgical macroreentry atrial tachycardias (PS-MATs) are atriotomy related; however, underlying mechanisms and prevention remain undefined.
The purpose of the present study was to investigate the electrophysiological and histologic bases of right atriotomy incision arrhythmogenicity and whether a modified atriotomy that extends the incisional line to the tricuspid annulus (TA) and inferior vena cava (IVC) prevents PS-MAT.
Atrial arrhythmia induction and electrophysiological and histologic characteristics were studied 8 weeks after right atriotomy in 30 adult swine according to incision distance to TA or IVC (groups A, B, and C: broad, narrow, and closed corridors, respectively; group D, no-incision sham; n = 6 per group, except n = 12 for group B).
Sustained PS-MATs were induced and mapped in the broad- and narrow-corridor groups (A, 1 of 6 [16.7%] vs B, 5 of 12 [41.7%]) but not in the closed-corridor (C) or sham (D) groups (P = .087). With 20-ms pacing cycle-length decrements (from 350 to 270 ms), mean conduction time over 20 mm at the atriotomy-to-TA corridor was 29.2 ± 2.2, 31.0 ± 4.2, 26.0 ± 1.9, and 17.0 ± 1.4 ms for 5 and 10 mm (both group B), 15 mm (group A), and sham incision (P = .017), respectively. Conduction properties correlated with histologic findings: the wider the corridor, the healthier its tissue. In group C (modified atriotomy), both corridors were replaced by dense scar with complete conduction block.
Atriotomy corridor width determines conduction properties and contributes to arrhythmogenicity. A modified right atriotomy that extends to the TA and IVC prevents PS-MAT.
大多数手术后的大折返性房性心动过速（PS-MAT）与房间隔切开术相关；然而，潜在的机制和预防措施仍未明确。
本研究旨在探讨右心房切开术切口致心律失常的电生理和组织学基础，以及是否通过将切口线延伸至三尖瓣环（TA）和下腔静脉（IVC）的改良切口可以预防 PS-MAT。
根据切口距离 TA 或 IVC 将 30 只成年猪分为 4 组（A、B、C 和 D 组，分别为宽、窄和闭合通道，以及无切口假手术组；每组 6 只，除 B 组 12 只），在右心房切开术后 8 周研究心房心律失常的诱发和电生理及组织学特征。
在宽通道组（A 组：6 只中有 1 只[16.7%]）和窄通道组（B 组：12 只中有 5 只[41.7%]）中可诱发并标测到持续性 PS-MAT，但在闭合通道组（C 组）或假手术组（D 组）中则不能（P =.087）。当起搏周长从 350 毫秒缩短至 270 毫秒时，在心房切开至 TA 通道的 20 毫米处，平均传导时间分别为 29.2 ± 2.2、31.0 ± 4.2、26.0 ± 1.9 和 17.0 ± 1.4 毫秒，对于 5 毫米和 10 毫米（均为 B 组）、15 毫米（A 组）和假手术切口（P =.017）。传导特性与组织学发现相关：通道越宽，其组织越健康。在 C 组（改良心房切开术）中，两个通道均被致密瘢痕替代，导致完全传导阻滞。
心房切开术的通道宽度决定了传导特性，并导致心律失常。延伸至 TA 和 IVC 的改良右心房切开术可预防 PS-MAT。
