Oxford Heart Centre, John Radcliffe Hospital NHS Trust, Oxford OX3 9DU, UK.
Eur Heart J. 2011 Aug;32(15):1881-90. doi: 10.1093/eurheartj/ehr117. Epub 2011 Apr 29.
Mitral isthmus (MI) ablation is technically challenging, requiring long endocardial ablation times and frequently coronary sinus (CS) ablation. The circumflex artery lies in the epicardium in close proximity to the CS and the mitral annulus and may potentially be injured during radiofrequency ablation.
Fifty-four patients underwent catheter ablation procedures that included MI ablation for treatment of atrial fibrillation. Irrigated ablation catheters were used with the following settings: endocardial surface (max power: 40/50 W at the annular end; max temperature: 48°C); CS (max power: 25/30 W; max temperature: 48°C). Coronary angiography was performed pre- and post-ablation and analysed by two cardiologists with quantitative coronary angiography. Mitral isthmus block was achieved in 89% of patients (60% required CS ablation). Fifteen patients (28%) had angiographic changes following ablation: eight had mid-circumflex narrowing only, one had circumflex and obtuse marginal (OM) artery narrowing, one had OM narrowing only, and five had distal circumflex occlusion/narrowing. Five patients had significant narrowing (50-84%), which resolved with intracoronary glycerine trinitrate. Fourteen (93%) of the patients with circumflex 'injury' had CS ablation and a longer mean CS ablation time (5.0 ± 3.0 vs. 2.6 ± 3.3 min, P = 0.03). Patients with distal circumflex occlusion had significantly smaller vessel diameter (1.0 ± 0.1 vs. 2.1 ± 0.2 mm, P = 0.03). A shorter distance between the circumflex and the CS was also associated with circumflex 'injury' (3.2 ± 1.9 vs. 5.6 ± 3.2 mm, P = 0.04). There were no electrocardiographic or echocardiographic abnormalities and no angina symptoms during follow-up.
Acute sub-clinical circumflex 'injury' following MI ablation is not uncommon. Ablation within the CS, proximity of the circumflex and the CS, and a small distal circumflex were risk factors for 'injury'.
峡部消融术技术难度大，需要较长的心内膜消融时间，并且经常需要进行冠状窦（CS）消融。回旋支动脉位于心外膜，紧邻 CS 和二尖瓣环，在射频消融过程中可能会受到损伤。
54 例患者接受了导管消融术，包括峡部消融术，用于治疗心房颤动。使用灌流消融导管，以下列参数进行消融：心内膜表面（环形末端最大功率：40/50 W；最大温度：48°C）；CS（最大功率：25/30 W；最大温度：48°C）。消融前后进行冠状动脉造影，并由两位心脏病专家进行定量冠状动脉造影分析。89%的患者实现了峡部阻滞（60%需要 CS 消融）。15 例（28%）患者消融后出现血管造影改变：8 例仅出现回旋支中段狭窄，1 例出现回旋支和钝缘支（OM）动脉狭窄，1 例仅出现 OM 狭窄，5 例出现回旋支远段闭塞/狭窄。5 例患者存在明显狭窄（50-84%），经冠状动脉内甘油三硝酸酯治疗后狭窄缓解。14 例（93%）回旋支“损伤”患者行 CS 消融，且 CS 消融时间更长（5.0±3.0 比 2.6±3.3 min，P=0.03）。回旋支远段闭塞患者的血管直径明显较小（1.0±0.1 比 2.1±0.2 mm，P=0.03）。回旋支与 CS 之间的距离较短也与回旋支“损伤”相关（3.2±1.9 比 5.6±3.2 mm，P=0.04）。随访期间无心电图或超声心动图异常，无胸痛症状。
MI 消融术后急性亚临床回旋支“损伤”并不少见。CS 内消融、回旋支与 CS 接近程度以及回旋支远段较小是“损伤”的危险因素。
