传统右心室起搏（right ventricular pacing, RVP）作为缓慢性心律失常患者的常规起搏治疗方式已在临床上获得广泛的认可和应用。然而，作为非生理性起搏方式，长期高负荷的右心室起搏会对患者术后的心脏机械同步性和心脏收缩功能造成损害，大量研究已证明其可增加患者术后心脏衰竭及住院死亡等临床不良事件发生的风险。为降低患者术后相关风险并增加手术获益，临床工作者们已经进行了长期大量的尝试和研究，因而生理性起搏是目前在心脏起搏领域发挥着愈发重要的作用和影响。希氏束起搏（His-bundle pacing, HBP）是最先于2000年被提出的起搏方式，它通过刺激希氏束将电刺激信号传导至左右心室进行起搏，也是至今为止临床上最符合正常生理状态下心脏激动顺序的起搏方式。但希氏束起搏本身解剖位置的特点在临床上对术者实现希氏束起搏提出了较高的挑战，因而希氏束起搏目前在临床上仍然难以得到广泛应用和推广。而后续由我国黄伟剑教授等人提出的左束支起搏（Left bundle branch pacing, LBBP）则是生理性起搏领域一项突破性的创新。左束支起搏可通过术中夺获左束支实现心室的起搏，这也使得其具备更加广阔的应用前景。一方面，左束支起搏较希氏束起搏而言更易实现术中心脏传导束的的捕获，而手术难度的降低也使得前者在临床上具备更高的适用性和可推广度；另一方面，左束支起搏和希氏束起搏均可实现窄QRS波起搏，但前者的起搏阈值较后者更低，同时也具备更优的长期稳定性。目前左束支起搏的临床获益已获得了较为一致的肯定，大量研究证实，相较于传统右心室起搏，接受左束支起搏的患者在术后具备更优的心脏收缩同步性，而且相较传统双心室起搏其亦可明显改善心衰患者的收缩功能。但左束支起搏存在尚需解决的问题：因左束支区域解剖结构的特点，由X线引导的左束支起搏，其手术时间和辐射时间均要明显高于传统右心室起搏，进而给术者和患者带来了更高的术中辐射暴露剂量和相关风险。而经胸超声心动图作为临床上常见的无创无辐射心脏检查技术，其在引导实现低辐射甚至零辐射左束支起搏方面具备较大潜力。但虽然其已被广泛用于术前术后心脏功能的筛查评估，目前临床上尚缺乏其引导左束支起搏的相关循证医学证据。因此，为了减少乃至避免术者及患者在左束支起搏术中的辐射暴露及相关风险，也为推广更为安全的起搏模式积累相关临床证据，本研究对于经胸超声心动图引导左束支起搏开展了一项前瞻性随机对照临床研究，综合比较了经胸超声心动图和X线引导的左束支起搏的多项临床结局，探索了经胸超声引导左束支起搏降低术中X线辐射的可行性及相关影响因素，为该引导方式将来在临床上的推广应用提供了一定的参考意义。

传统右心室起搏（right ventricular pacing, RVP）作为缓慢性心律失常患者的常规起搏治疗方式已在临床上获得广泛的认可和应用。然而，作为非生理性起搏方式，长期高负荷的右心室起搏会对患者术后的心脏机械同步性和心脏收缩功能造成损害，大量研究已证明其可增加患者术后心脏衰竭及住院死亡等临床不良事件发生的风险。为降低患者术后相关风险并增加手术获益，临床工作者们已经进行了长期大量的尝试和研究，因而生理性起搏是目前在心脏起搏领域发挥着愈发重要的作用和影响。希氏束起搏（His-bundle pacing, HBP）是最先于2000年被提出的起搏方式，它通过刺激希氏束将电刺激信号传导至左右心室进行起搏，也是至今为止临床上最符合正常生理状态下心脏激动顺序的起搏方式。但希氏束起搏本身解剖位置的特点在临床上对术者实现希氏束起搏提出了较高的挑战，因而希氏束起搏目前在临床上仍然难以得到广泛应用和推广。而后续由我国黄伟剑教授等人提出的左束支起搏（Left bundle branch pacing, LBBP）则是生理性起搏领域一项突破性的创新。左束支起搏可通过术中夺获左束支实现心室的起搏，这也使得其具备更加广阔的应用前景。一方面，左束支起搏较希氏束起搏而言更易实现术中心脏传导束的的捕获，而手术难度的降低也使得前者在临床上具备更高的适用性和可推广度；另一方面，左束支起搏和希氏束起搏均可实现窄QRS波起搏，但前者的起搏阈值较后者更低，同时也具备更优的长期稳定性。目前左束支起搏的临床获益已获得了较为一致的肯定，大量研究证实，相较于传统右心室起搏，接受左束支起搏的患者在术后具备更优的心脏收缩同步性，而且相较传统双心室起搏其亦可明显改善心衰患者的收缩功能。但左束支起搏存在尚需解决的问题：因左束支区域解剖结构的特点，由X线引导的左束支起搏，其手术时间和辐射时间均要明显高于传统右心室起搏，进而给术者和患者带来了更高的术中辐射暴露剂量和相关风险。而经胸超声心动图作为临床上常见的无创无辐射心脏检查技术，其在引导实现低辐射甚至零辐射左束支起搏方面具备较大潜力。但虽然其已被广泛用于术前术后心脏功能的筛查评估，目前临床上尚缺乏其引导左束支起搏的相关循证医学证据。因此，为了减少乃至避免术者及患者在左束支起搏术中的辐射暴露及相关风险，也为推广更为安全的起搏模式积累相关临床证据，本研究对于经胸超声心动图引导左束支起搏开展了一项前瞻性随机对照临床研究，综合比较了经胸超声心动图和X线引导的左束支起搏的多项临床结局，探索了经胸超声引导左束支起搏降低术中X线辐射的可行性及相关影响因素，为该引导方式将来在临床上的推广应用提供了一定的参考意义：

经胸超声心动图与X线引导的左束支起搏治疗缓慢性心律失常的疗效对比研究

目的：本研究旨在通过对比经胸超声心动图（transthoracic echocardiography, TTE）与X线引导的左束支起搏（Left bundle branch pacing, LBBP）在术中成功率、手术时间、辐射时间等方面的差异，并评估TTE引导左束支起搏以降低术中辐射暴露在临床上的可行性和安全性。

方法：本研究为单中心、前瞻性、随机对照研究。连续入选本团队自2022年6月至2022年11月间符合国际指南推荐的符合永久起搏器植入指征的缓慢性心律失常患者，并1:1随机分至TTE或X线引导的左束支起搏组。术后对患者每3个月进行一次随访，共计随访6个月。在术中和随访期间详细记录并比较了两组患者在手术成功率、手术时间、辐射时间、起搏参数、心电和超声参数以及相关并发症等方面的差异。

结果：研究共纳入60名患者。30名患者被分配到X线组，左束支起搏手术成功率为86.7%（26/30）；另外30名患者被分配到TTE组，左束支起搏手术成功率为76.7%（23/30）。TTE组的手术时间与X线组相比略有降低，但差异无统计学意义（9.0 min vs. 12.0 min, P = 0.063）。然而TTE组的术中X线辐射时间要显著低于X线组（2.5 min vs. 5.0 min, P = 0.002）。在术中植入时和术后随访期间，两组在起搏参数、心电和超声参数以及相关并发症方面差异亦无统计学意义。

结论：TTE引导左束支起搏是一种可行且安全的手术方式。与X线相比，TTE引导的左束支起搏虽不能显著提高手术成功率或降低手术时间，但能明显缩短术中辐射时间。

Abstact

Traditional right ventricular pacing (RVP) has gained widespread recognition and application in clinical practice as a routine pacing treatment for patients with bradycardic arrhythmias. However, as a non-physiological pacing method, long-term high-burden right ventricular pacing can impair postoperative cardiac mechanical synchrony and contractile function, with extensive research demonstrating an increased risk of adverse clinical events such as postoperative heart failure and hospital mortality. To reduce postoperative risks and enhance surgical benefits, clinicians have conducted extensive trials and research, making physiological pacing increasingly significant in the field of cardiac pacing. His-bundle pacing (HBP), first introduced in 2000, paces through stimulating the His bundle to conduct electrical stimuli to the left and right ventricles, representing the pacing method that most closely aligns with the normal physiological sequence of cardiac excitation. However, the anatomical positioning of His bundle pacing poses significant clinical challenges, limiting its widespread adoption. Subsequently, left bundle branch pacing (LBBP), a breakthrough innovation proposed by Professor Wei-Jian Huang and others, captures the left bundle branch intraoperatively to pace the ventricles, offering broader application prospects. On one hand, LBBP facilitates easier capture of the cardiac conduction bundle intraoperatively compared to HBP, enhancing its clinical applicability and scalability; on the other hand, both LBBP and HBP achieve narrow QRS wave pacing, but the former has a lower pacing threshold and superior long-term stability. Current clinical benefits of LBBP have been consistently acknowledged, with studies showing that patients receiving LBBP have better postoperative cardiac synchrony and improved contractile function compared to traditional right ventricular pacing. However, LBBP faces challenges, as X-ray-guided LBBP, due to the anatomical characteristics of the left bundle branch area, involves longer surgery and radiation exposure times than traditional right ventricular pacing, increasing intraoperative radiation doses and associated risks for operators and patients. Transthoracic echocardiography, a non-radiation cardiac examination technique, holds potential for guiding low-radiation or even zero-radiation LBBP. Although widely used for pre- and postoperative cardiac function assessment, there is a lack of evidence-based medicine supporting its use in guiding LBBP. Therefore, to minimize or avoid radiation exposure and related risks for operators and patients during LBBP, and to accumulate evidence for promoting safer pacing modalities, this study conducted a prospective randomized controlled clinical trial on transthoracic echocardiography-guided LBBP, comparing various clinical outcomes with X-ray-guided LBBP, exploring the feasibility and influencing factors of reducing intraoperative X-ray radiation through transthoracic echocardiography guidance, and providing reference for the future clinical application of this guidance method:

Comparison of clinical outcomes between transthoracic echocardiography- and X-ray-guided left bundle branch pacing for bradycardia

Objective: This study aims to evaluate the feasibility and safety of transthoracic echocardiography (TTE) guided left bundle branch pacing (LBBP)，especially in  in reducing intraoperative radiation exposure .

Methods: This single-center, prospective, randomized controlled study included patients with bradycardic arrhythmias who met the international guidelines for permanent pacemaker implantation from June 2022 to November 2022. Patients were randomly assigned 1:1 to either the TTE-guided or X-ray-guided LBBP group. Postoperative follow-ups were conducted every three months for a total of six months. Detailed records and comparisons of intraoperative success rates, procedural time, fluoroscopy time, pacing parameters, electrocardiographic and echocardiographic parameters, and related complications were made between the two groups during the operation and follow-up period.

Results: 60 patients were enrolled in this study. 30 patients were allocated to X-ray group, with a success rate of 86.7% (26/30), and the other 30 patients were assigned to TTE group, with a success rate of 76.7% (23/30). The procedure time of TTE group was comparable to that of the X-ray group (9.0 min vs. 12.0 min, P=0.063). However, the fluoroscopy time in the TTE group was significantly lower than that of the X-ray group (2.5 min vs. 5.0 min, P=0.002). There were no statistically significant differences in pacing parameters, electrophysiological and echocardiographic characteristics, or complications between the two groups at implantation and during follow-up.

Conclusion: TTE-guided LBBP is a feasible and safe method. Compared with X-ray, TTE showed a comparable success rate and procedure time, but it could significantly reduce the fluoroscopy time of LBBP.