Permanent His-bundle pacing in the right atrium in a patient with a Mobitz II atrioventricular block: a case presentation

Background This case report presents a patient diagnosed with sick sinus syndrome who was successfully treated with permanent His-bundle pacing (PHBP). Case presentation A 36-year-old man was transferred to our hospital due to recurrent syncope. He was diagnosed with sick sinus syndrome based on the 24-h Holter and a history of syncope. He was admitted to hospital and successfully treated with PHBP. The postoperative examination showed that the pacing rhythm, pacemaker pacing and perception function were normal. He was discharged without any complications after a successful pacemaker implantation. Conclusions We described a case in which PHBP may become an optimal approach to the management of patients with sick sinus syndrome. Right ventricular pacing has been attempted with inconsistent efficacy outcomes. HBP provides a promising alternative pacing option that might provide symptom resolution to patients with sick sinus syndrome.

283 His bundle pacing: safety, performance, and clinical outcomes in a single-centre experience

Aims Permanent His bundle pacing (HBP) is a more physiological technique for cardiac stimulation and has recently emerged as an alternative for anti-bradycardia pacing and cardiac resynchronization therapy (CRT). Its main advantages over ‘classical’ pacing are both its protective role over pacing-induced cardiomyopathy and the possibility of resynchronization by normalization of His-Purkinje activation. To evaluate the intermediate-term outcomes of HBP in terms of safety, performance, and clinical outcomes. Methods and results Between December 2018 and July 2020, we enrolled a series of consecutive patients with indication for pacing in whom HBP was attempted. A specific lead (3830 Select Secure MRI SureScan) and sheath (C315His) was used. At follow-up clinical, safety and performance outcomes were evaluated. A significant rise in HBP pacing threshold was defined as an increase of at least 1 V@1ms in the minimum voltage that could produce an effective myocardial depolarization. Remote or in-hospital device interrogation was performed by an experienced electrophysiologist. HBP was attempted in 99 patients and all implantations were performed by the same two operators. Eighty-two procedures were successful (83%). The main reasons for HBP failure were high pacing-thresholds (n = 8, 47%), infra-Hisian block (n = 5, 29,4%), difficult HB location (n = 3, 17,6%), unsatisfactory sensing (n = 1, 5,9%), or lead instability (n = 1, 5,9%). During a mean follow-up of 9.5 ± 5.9 months, the overall technical and clinical complication rates were 39% and 13.3%, respectively. Three (3.6%) patients underwent His lead extraction and subsequent conventional right ventricular septum (RV) lead implantation because of lead dislodgement (n = 2) or rise in pacing threshold (n = 1), while two (2.4%) patients required His lead repositioning because of lead dislodgement (n = 1) and phrenic nerve stimulation (n = 1). Nineteen patients (23.2%) experienced a significant rise in Hisian pacing threshold and 1 of these patients also had poor sensing parameters. Oversensing was noted in 8 (9.7%) patients and in 7 of them (87.5%) it was due to both atrioventricular and ventriculoatrial crosstalk events. As regards clinical outcomes, seven patients (8.5%) were diagnosed with new onset atrial fibrillation (AF), one of them complicated by stroke. Three patients (3.6%) were hospitalized for acute heart failure, one of them after His lead dislodgement. Finally, five patients (6.1%) died during follow-up, but no death was related to cardiovascular events. Conclusions HBP is an effective technique to obtain a more physiological cardiac pacing, but it is limited by a moderate rate of procedural failure and follow-up complications, mainly rising in pacing threshold and oversensing events. This is probably due to suboptimal implantation tools and lack of specific programming algorithms. New dedicated tools, increased experience, knowledge of device limitations, and optimal programming are needed to improve future outcomes.

557 His bundle pacing: how to troubleshoot the implantation of a ventricular back-up lead

Aims Interest in permanent His bundle pacing (HBP) as a means of both preventing pacing-induced cardiomyopathy and providing physiological resynchronization by normalization of His-Purkinje activation is constantly growing. Current devices are not specifically designed for HBP, which gives rise to programming challenges. To evaluate the critical troubleshooting HBP options in patients with permanent atrial fibrillation (AF) and variable degree of atrio-ventricular block (AVB) who receive HBP through a lead connected to the atrial port, and an additional ventricular ‘backup’. Methods and results Between December 2018 and July 2021, 156 consecutive patients with indication for pacing underwent HBP. Among these, 37 had permanent AF with documented symptomatic pauses. Fourteen of them received a dual-chamber device which was used to place a backup right ventricle (RV) lead; in this scenario, the His lead is implanted in the right atrial (RA) port, the RV lead in the RV port. Depending on the presence of an additional left ventricle (LV) lead, either a dual-chamber and a CRT device can be used. In this context, the events marked as atrial sensed (As) or paced (Ap) are indeed ventricular, so that sensing is more complex. A clinical scenario is atrial activity oversensed on the His channel (As) leading to RV dyssynchronous pacing in the ventricular safety pacing (VSP) window. A second one is intrinsic QRS undersensing causing inappropriate His pacing. The interplay of intrinsic ventricular activity (rate, signal amplitude, and slew rate on both the His and the ventricular channel) and of the HV interval may be of key importance to troubleshoot As–Vp (atrial sensed–ventricular paced) (Figure 1A) as well as Vs–Ab (ventricular sensed–atrial blanking period) sequences (Figure 1B). Changing sensitivity and sensing configuration may help to fix these issues. DVI(R) mode programming may indeed prove safer than DDD(R) in the setting of preserved intrinsic activity or in the event of intermittent His capture loss. Paced AV delay should be programmed slightly longer than H-V+QRS duration to avoid unnecessary RV pacing with pseudo-fusion (too short) (Figure 2A) and possibly R/T events (too long). Stability of H-V interval and of QRS duration must be verified at each device follow-up by decremental His pacing to ensure consistent sensitivity of the ventricular signal beyond stable His capture, that may be challenged by infra-Hisian block (Figure 2B). Conclusions Owing to the absence of HBP-specific devices, HBP shall be made safe and effective by careful troubleshooting, consisting of sensitivity setting, paced AV interval and mode programming. 557 Figure

204 Permanent his bundle pacing using stylet-driven lead in patients with right atriomegaly: a single-centre experience

Aims His bundle pacing (HBP) is becoming an increasing widespread approach for physiological pacing. However, successful HBP procedure could be hampered by limited implantation tools especially in challenging anatomies. We aimed to report our experience with HBP technique using a novel stylet-driven lead system in patients with right atriomegaly. Methods and results Consecutive patients with right atrium (RA) volume >25 ml/m2 in men and >21 ml/m2 in women who underwent permanent HBP for standard indications were enrolled from March 2020 to March 2021. The tool of first choice for HBP attempt was a stylet-driven lead (Solia S 60, Biotronik) delivered via a dedicated introducer sheath (Selectra 3D, Biotronik). The acute, 1-month and 6-month procedural success rates were assessed. We enrolled 24 patients [median age: 75 (70–79) years, 85% men] with an average RA volume of 50.7 ± 7.8 ml/m2. At implant, conduction system pacing using stylet-driven lead was achieved in 21 patients (87%): 12 (50%) selective HBP, 6 (25%) non-selective HBP, and 3 (12.5%) left bundle branch area pacing. In the three failures, HBP was further attempted with a lumen-less lead with fixed helix (SelectSecure 3830, Medtronic) with final procedural success in two cases. In the successful cases, there was a significant reduction of QRS duration between paced and spontaneous beats [152.5 (130–167.5) ms vs. 130 (122.5–137.5) ms, P = 0.003]. No lead dislodgment nor significant pacing threshold increase was observed at 1-month (1.30 ± 0.76 [email protected] vs. 1.32 ± 0.80 [email protected] ms, P > 0.9) and 6-month follow-up (1.30 ± 0.76 [email protected] vs. 1.38 ± 0.97 [email protected] ms, P = 0.66). Conclusions In patients with right atriomegaly, the novel stylet-driven lead system showed high implant success rates with stable pacing thresholds.