Feasibility of Conduction System Pacing in Patients with Baseline Bundle Branch Block-A Single-Center Mid-Term Follow-Up Study.

BACKGROUND: The primary prerequisite for a successful conduction system pacing (CSP) procedure is the integrity of the conduction system, which may be impaired if a baseline bundle branch block (BBB) is present. This study aimed to evaluate the feasibility and mid-term performance of permanent CSP in patients with baseline BBB and to compare the results between left bundle branch block (LBBB) and right bundle branch block (RBBB) patterns. MATERIAL AND METHODS: A total of 101 patients with typical BBB and an attempt at CSP were retrospectively reviewed. Procedural characteristics, pacing, sensing parameters, and complications at baseline and after a mid-term follow-up were analyzed. RESULTS: The global procedural success for CSP was 93%. His bundle pacing (HBP) had a significantly lower success rate than left bundle branch area pacing (LBBAP) (50.5% vs. 86%). The paced QRS duration was significantly narrower with HBP. The pacing and sensing thresholds were significantly better with LBBAP. Procedural complications occurred only in the LBBAP group (two acute perforations in the LV cavity and one acute chest pain during lead fixation) without long-term sequelae. The HBP and the LBBAP procedural success rates were higher in the RBBB versus the LBBB group (62.5% vs. 44.9% and 100% vs. 81.5%, respectively). Baseline QRS duration, atrial volumes, and right ventricular diameters were significantly associated with HBP procedural failure. The follow-up pacing and sensing thresholds were similar to the baseline values for all pacing methods and BBB morphology. Only one device-related complication leading to pacing interruption was recorded. CONCLUSION: In patients with bundle branch blocks, CSP is a feasible procedure associated with a high success rate, stable pacing and sensing parameters, and low complication rates over a mid-term follow-up.

His bundle pacing in nodal versus infranodal atrioventricular block: a mid-term follow-up study.

INTRODUCTION: This study evaluated the feasibility of His bundle pacing (HBP) in consecutive, unselected patients with advanced atrioventricular block (AVB) over a medium-term follow-up period, comparing procedural characteristics between nodal and infranodal sites of the conduction block. MATERIALS AND METHODS: Seventy-five consecutive patients with second-degree or third-degree AVB in which HBP was attempted were prospectively included in this study. The clinical and procedural-related characteristics of the patients were recorded at baseline and over a mid-term follow-up. RESULTS: 72% of the patients had normal QRS duration at baseline. Intracardiac electrograms revealed nodal AVB in 46 patients (61.3%). The permanent HBP procedural success was significantly higher in nodal AVB (84.8%) vs infranodal AVB (31%). There was no statistical difference between paced QRS duration, impedance, pacing and sensing thresholds and fluoroscopy time in the two groups. Infranodal block, baseline QRS duration, left bundle branch block morphology and ejection fraction were significantly associated with HBP procedural failure. The patients were followed for a period of 627.71±160.93 days. There were no significant differences in parameters at follow-up. An increase of >1 V in the His bundle (HB) capture threshold was encountered in one patient with infranodal AVB (11.1 %) and in four patients with nodal AVB (10.25%). CONCLUSION: Permanent HBP is a feasible pacing technique in nodal AVB with a high success rate and stable thresholds in the medium term. Most infranodal blocks are located within the HB, so there is still the possibility to capture the conduction system, although with lower success rates.

Feasibility of Permanent His Bundle Pacing in the Elderly vs the Very Elderly. A Single-Center Mid-Term Follow-Up Study.

Purpose: Although feasibility studies have included older patients, specific data for His bundle pacing (HBP) in this population is scarce. The aim of this study was to evaluate the feasibility and mid-term performance of HBP in the elderly (70 to 79 years old) versus the very elderly (80 years old and above) patients with conventional indications for pacing. Patients and Methods: About 105 patients older than 70 years of age with attempted HBP from the 1st of January 2019 to the 31st of December 2021 were reviewed. Clinical and procedural characteristics were recorded at baseline, and after a mid-term follow-up period. Results: The procedural success rate was similar in both age groups (68.49% vs 65.62%). There was no significant difference in pacing or sensing thresholds, impedance, and fluoroscopy times. For both age intervals, patients with a baseline narrow QRS maintained a similar QRS duration after pacing, while in patients with a wide QRS, the paced QRS was significantly shorter. Baseline QRS duration, left bundle branch block morphology, and ejection fraction, were significantly associated with HBP procedural failure. The mean follow-up period was 830.34 days for the elderly and 722.76 days for the very elderly. After the follow-up period, both sensing and pacing thresholds were similar between the groups. Compared to the baseline values, there were no significant changes in both pacing and sensing parameters, irrespective of the age interval. During follow-up, no lead dislodgements were recorded. There were two cases of significant pacing threshold rise in the elderly (4%) and three cases in the very elderly group (14.2%) which were managed conservatively, without lead revision. Conclusion: In elderly and very elderly patients, HBP is a feasible procedure associated with constant pacing and sensing parameters and with low complication rates over mid-term follow-up.

Comparison of Depolarization and Repolarization Parameters in Left vs. Right Ventricular Septal Pacing-An Intraprocedural Electrocardiographic Study.

Compared with conventional right ventricular septal pacing (RVSP), several studies have shown a net clinical benefit of left bundle branch area pacing (LBBAP) in terms of ejection fraction preservation and reduced hospitalizations for heart failure. The purpose of this study was to compare acute depolarization and repolarization electrocardiographic parameters between LBBAP and RVSP in the same patients during the LBBAP implant procedure. We prospectively included 74 consecutive patients subjected to LBBAP from 1 January to 31 December 2021 at our institution in the study. After the lead was placed deep into the ventricular septum, unipolar pacing was performed and 12-lead ECGs were recorded from the distal (LBBAP) and proximal (RVSP) electrodes. QRS duration (QRSd), left ventricular activation time (LVAT), right ventricular activation time (RVAT), QT and JT intervals, QT dispersion (QTd), T-wave peak-to-end interval (Tpe), and Tpe/QT were measured for both instances. The final LBBAP threshold was a 0.7 ± 0.31 V at 0.4 ms duration with a sensing threshold of 10.7 ± 4.1 mV. RVSP produced a significantly larger QRS complex than the baseline QRS (194.88 ± 17.29 ms vs. 141.89 ± 35.41 ms, p < 0.001), while LBBAP did not significantly change the mean QRSd (148.10 ± 11.52 ms vs. 141.89 ± 35.41 ms, p = 0.135). LVAT (67.63 ± 8.79 ms vs. 95.89 ± 12.02 ms, p < 0.001) and RVAT (80.54 ± 10.94 ms vs. 98.99 ± 13.80 ms, p < 0.001) were significantly shorter with LBBAP than with RVSP. Moreover, all the repolarization parameters studied were significantly shorter in LBBAP than in RVSP (QT-425.95 ± 47.54 vs. 487.30 ± 52.32; JT-281.85 ± 53.66 vs. 297.69 ± 59.02; QTd-41.62 ± 20.07 vs. 58.38 ± 24.44; Tpe-67.03 ± 11.19 vs. 80.27 ± 10.72; and Tpe/QT-0.158 ± 0.028 vs. 0.165 ± 0.021, p < 0.05 for all), irrespective of the baseline QRS morphology. LBBAP was associated with significantly better acute depolarization and repolarization electrocardiographic parameters compared with RVSP.

The Impact of Cardiac Chamber Volumes on Permanent His Bundle Pacing Procedural Outcomes-A Single Center Experience.

His bundle pacing (HBP) has several pitfalls, such as the inability to identify the His bundle and lack of capture at acceptable thresholds. The majority of data regarding HBP were obtained using a dedicated non-deflectable delivery system. This study aimed to evaluate the impact of cardiac chamber dimensions on permanent HBP procedural outcomes when using this type of fixed-curve catheter. Seventy-two patients subjected to HBP from the 1st of January to the 31st of December 2021 at our institution were retrospectively reviewed. The baseline clinical characteristics and echocardiographic measurements of all the cardiac chambers were recorded, as well as procedural outcomes (HB electrogram identification and overall procedural success). During the procedure, the HB electrogram was recorded in 59 patients (81.9%) and successful permanent HBP was achieved in 33 patients, representing 45.8% of all the studied patients. Left atrial (LA) and right atrial (RA) volumes were significantly higher in patients without HB electrogram identification. Only LA and RA volumes were statistically associated with HB electrogram localization, while there was no significant association between the echocardiographic parameters and procedural success. LA volumes above 93 mL and RA volumes above 60 mL had an 8.81 times higher chance of failure to localize the HB electrogram compared with patients with lower volumes (p < 0.001). When considering non-deflectable delivery catheters for HBP, careful preprocedural echocardiographic analysis of the atrial volumes could help in the proper selection of implanting tools, thus optimizing the procedural outcomes and costs.

Left bundle branch area pacing - restoring the natural order: A Case Report.

INTRODUCTION: Recent studies have shown that His-bundle pacing could be an alternative in patients requiring cardiac resynchronization therapy as it is comparable or better in terms of amelioration of ventricular activation, narrowing of the QRS complex, or clinical outcomes. However, in case of high threshold at the level of His-bundle or inability to correct conduction through a diseased His-Purkinje system other option should be searched like left bundle pacing. PATIENT CONCERNS: A 77-year-old man presented to the Emergency Department for dizziness and dizziness and lightheadedness due to an intermittent 2:1 atrioventricular block with a QRS complex morphology of a major left branch block. DIAGNOSIS: Given the documented symptomatic 2:1 AV block, according to the European Guideliness the patient was considered to have a class 1 indication of permanent double chamber cardiostimulation. INTERVENTIONS: A lead delivery system with a C315 His catheter and a Select Secure 3830 69 cm pacing lead were placed at the His bundle area with important narrowing of the QRS complex but with an unacceptable high threshold. The delivery system was moved towards the apex 1,5 cm and the lead screwed deep into the septum until capture of the left bundle branch was achieved with complete normalization of the conduction troubles. OUTCOMES: At 3 month follow-up the patient was asymptomatic and the pacing and sensing thresholds remained at same values as during implantation: 0.75/0.4 ms and 14 mV respectively. CONCLUSION: Left bundle-pacing represents the next step of His-Purkinje system pacing to overcome all difficulties related to His-bundle pacing.

His bundle pacing - a curative method: A Case Report.

INTRODUCTION: Pacing of the His bundle and conduction system seems an attractive site for pacing. Lead placement in His-pacing might be technically challenging due to surrounding structures and particular anatomic location. PATIENT CONCERNS: A 62-years old male patient was admitted for recurrent syncope. Electrocardiographic monitoring revealed periods of complete atrioventricular block with left branch block morphology and a QRS duration of 160 ms. DIAGNOSIS: A diagnosis of intermittent complete atrioventricular block was made with a Class I indication of permanent dual-chamber cardiac pacing. INTERVENTIONS: A lead delivery system with a C315 His catheter and a Select Secure 3830 69 cm pacing lead was placed at the septal area of the atrioventricular junction with good pacing and sensing thresholds. An important narowing of the QRS was observed. OUTCOMES: After the procedure, good pacing and sensing parameters were observed.Echocardiography revealed disappearance of the previously recorded ventricular dyssynchronism.Device follow-up at 1 month and 3 months showed stable pacing and sensing parameters. CONCLUSION: Pacing the distal His bundle normalized the QRS complex, therefore "curing" both the atrioventricular and the left bundle branch conduction abnormalities. As such, the technique can be used as an alternative to cardiac electrical resynchronization therapy with acceptable pacing and detection thresholds and better ventricular activation pattern.