Background:Alcohol septal ablation (ASA) is a treatment option in patients with drug-refractory symptomatic hypertrophic obstructive cardiomyopathy (HOCM). In many patients, right bundle branch block (RBBB) develops during ASA because septal branches supply the right bundle branch. However, the clinical significance of procedural RBBB is uncertain.

Methods and Results:We retrospectively reviewed 184 consecutive patients with HOCM who underwent ASA. We excluded 40 patients with pre-existing RBBB (n=10), prior pacemaker implantation (n=15), mid-ventricular obstruction type (n=10), and those lost to follow-up (n=5), leaving 144 patients for analysis. Patients were divided into 2 groups according to the development (n=95) or not (n=49) of procedural RBBB. ASA conferred significant decreases in the left ventricular pressure gradient (LVPG) in both the RBBB and no-RBBB group (from 74±48 to 27±27 mmHg [P<0.001] and from 75±45 to 31±33 mmHg [P<0.001], respectively). None of the RBBB patients developed further conduction system disturbances. The percentage reduction in LVPG at 1 year after the procedure was significantly greater in the RBBB than no-RBBB group (66±24% vs. 49±45%; P=0.035). Procedural RBBB was not associated with pacemaker implantation after ASA, but was associated with reduction in repeat ASA (odds ratio 0.34; 95% confidence interval 0.13–0.92; P=0.045).

Conclusions:Although RBBB frequently occurs during the ASA procedure, it does not adversely affect clinical outcomes.

背景：酒精间隔消融（ASA）是药物难治性症状性肥厚型梗阻性心肌病（HOCM）患者的一种治疗选择。许多患者在 ASA 期间出现右束支传导阻滞 (RBBB)，因为间隔分支供应右束支。然而，程序性 RBBB 的临床意义尚不确定。

方法和结果：我们回顾性地回顾了 184 名连续接受 ASA 的 HOCM 患者。我们排除了 40 名已存在 RBBB（n=10）、先前植入起搏器（n=15）、心室梗阻类型（n=10）和失访（n=5）的患者，剩下 144患者进行分析。根据程序性RBBB的发展（n = 95）或未发展（n = 49）将患者分为2组。ASA 使 RBBB 和无 RBBB 组的左心室压力梯度 (LVPG) 显着降低（从 74±48 到 27±27 mmHg [P<0.001] 和从 75±45 到 31±33 mmHg [P< 0.001]，分别）。RBBB 患者均未出现进一步的传导系统障碍。RBBB 组术后 1 年 LVPG 降低的百分比显着高于无 RBBB 组（66±24% 对 49±45%；P=0.035）。

结论：虽然 RBBB 在 ASA 手术过程中经常发生，但它不会对临床结果产生不利影响。