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.

Preliminary study on left bundle branch area pacing in children：clinical observation of 12 cases

Objective: To explore the safety and feasibility of left bundle branch area pacing (LBBAP) in children. Methods: This study observed 12 children attempted LBBAP from 2019 to 2021 in our department prospectively. Clinical data, pacing parameters, electrocardiograms, echocardiographic measurements and complications were recorded at implant and during follow-up. Results: The 12 patients aged between 3 and 14ys and weighted from 13 to 48kg. 11 patients were diagnosed with third-degree AVB and 1 patient (case 4) suffered from cardiac dysfunction due to right ventricular apical pacing (RVAP). LBBAP was successfully achieved in all patients with narrow QRS complexes. LVEF of case 4 recovered on the 3rd day after LBBAP. The median of LVEDD Z score of the 12 patients decreased from 1.75 to1.05 3 months after implantation (p<0.05). The median of paced QRS duration was 103ms. The median of pacing threshold, R-wave amplitude and impedance were 0.85V, 15mV and 717Ω respectively and remained stable during follow-up. No complications such as loss of capture, lead dislodgement or septal perforation occurred. Conclusions: LBBAP can be performed safely in children with narrow QRS duration and stable pacing parameters. Cardiac dysfunction caused by long-term RVAP can be corrected by LBBAP quickly.

Success and failure for implantation of left bundle branch pacing using stylet-driven pacing leads : a single center experience

Funding Acknowledgements Type of funding sources: None. Background/Introduction :Left bundle area pacing is a new modality of physiological pacing. By screwing the pacing lead deep into the interventricular septum, the left bundle branch could be recruited for pacing purpose. Initially left bundle area pacing was performed with fixed helix lead supported by the delivery catheter. On the other hand, there are studies showing the feasibility of using a style-driven extendable helix with the new delivery sheath for left bundle area pacing. Purpose :To study the feasibility of left bundle area pacing and explore factors associated with success and failure Methods :This is a retrospective study from September 2020 to January 2021 in a local hospital. Baseline patient characters, procedural characters, acute complication and reason for failure were recorded. Logistic regression was done to explore factors associated with success and failure. Results :In 14 patients, the mean age is 81 +/- 6.8 years with 28% female. Pacing indications were sick sinus syndrome (n = 3) and atrio-ventricular block (n = 11). The success rate is 64% (n = 9/14). The average R wave sensing was 11.4 +/- 4.5mV, the average V pacing threshold was 0.88 +/- 0.23V @ 0.4ms and average impedance was 633 +/- 93.6 Ohm. There were no septal perforation nor pericardial effusion after implantation. The most common reason for failure is lead dislodgement during implantation (n = 4) and the other reason is failure to locate and capture the left bundle (n = 1). In logistic regression, there was no clinical risk factor identified to predict failure for implantation , i.e. diabetics ( OR 0.95, p =0.15), hyperlipidaemia (OR 0.87, p =0.94), chronic renal disease (OR 0.88, p = 0.94), coronary heart disease (OR 0.37, p = 0.66). Gender(OR 4.5, p = 0.37), age(OR 1.1, p = 0.32) and hypertension(OR 25, p = 0.25) may appear to predict failure for implantation but the results were not statistically significant. Conclusion :Left bundle area pacing could be feasible and safely implanted using style-driven lead with good pacing parameters. No clinical factor is identified to predict the failure of implantation, the main reason for failure is dislodgement of lead during implantation. Similar finding was noted in a study comparing lumen-less lead and stylet-driven lead.2 In this study found that reason for failure of left bundle area pacing using style-driven lead was due to repetitive lead dislodgement after slitting the delivery sheath, fail advancement of lead into septum and loose septal endocardium. Stability and ability to screw into septum remain a great obstacle for left bundle area pacing using stylet-driven lead. This study is limited by small sampling size and single center retrospective study. Further studies are needed to see the long term outcome of left bundle area pacing using style-driven lead and investigate other methods to predict success/ failure of implantation, such as the role of imaging.

Procedure-Related Complications of Left Bundle Branch Pacing: A Single-Center Experience

Background: Although left bundle branch pacing (LBBP) has emerged as a novel physiological pacing strategy with a low and stable threshold, its safety has not been well-documented. In the present study, we included all the patients with procedure-related complications at our centre to estimate these LBBP cases with unique complications.Methods: We enrolled 612 consecutive patients who received the procedure in Zhongshan Hospital, Fudan University, between January 2018 and July 2020. Regular follow-ups were conducted (at 1, 3, and 6 months in the first year and every 6–12 months from the second year), and the clinical data of the patients with complications were collected and analyzed.Results: With a mean follow-up period of 12.32 ± 5.21 months, procedure-related complications were observed in 10 patients (1.63%) that included two postoperative septum perforations (2/612, 0.33%), two postoperative lead dislodgements (2/612, 0.33%), four intraoperative septum injuries (4/612, 0.65%), and two intraoperative lead fractures (2/612, 0.33%). Pacing parameters were stable during follow-up, and no major complications were observed after lead repositioning in the cases of septum perforation and lead dislodgement.Conclusion: The incidence of procedure-related complications for LBBP, namely postoperative septum perforation, postoperative lead dislodgement, intraoperative septum injury, and intraoperative lead fracture, were low. No adverse clinical outcomes were demonstrated after successful repositioning of the lead and appropriate treatment.

Delayed management of atrial lead dislodgment after pacemaker implantation: a case report

Background Pacemaker lead dislodgement may cause malfunction in the pacing system, which may lead to severe adverse events. For patients with sick sinus syndrome but normal atrioventricular conduction, atrial lead dislocation may cause excessive unnecessary ventricular pacing, resulting in nonphysiological pacing leading to heart failure. The longer the unwanted ventricular pacing continues, the greater the chances that irreversible heart failure may occur. Ironically, we admitted a patient who had been refusing dislodged lead relocation for 7 years. The symptoms of heart failure were significantly resolved after new atrial lead implantation. We reviewed her clinical data before and after the procedure and believed the case was worthy of reflection. Case presentation An 83-year-old Han Chinese woman presented with heart failure symptoms for 7 years due to the late macro-dislodgement of an atrial pacing lead. Her echocardiogram showed average left ventricular ejection fraction (LVEF) but reduced left ventricular end-diastolic volume (LVEDV) during right ventricular pacing, indicating heart failure with preserved ejection fraction (HFpEF). After 7 years of refusal, she finally agreed to implantation of a new atrial lead. She has been doing well since the operation. Conclusions For patients with sick sinus syndrome with dual-chamber pacemaker indication, atrial lead dislodgement should be appropriately managed if the atrioventricular function is normal. As the consequences are subtle and appear gradually, they might be overlooked by patients and even doctors. Implanting a new atrial lead is the right thing to do rather than just passively waiting or treating with symptom relief medications.