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.

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.

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.

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.

P516Permanent his bundle pacing: conclusions from the one-year experience of a romanian center

Background

Long term right ventricular pacing has been associated with an increased risk of heart failure development due to pacing induced cardiomyopathy. Therefore, alternatives of more physiological pacing have been evaluated. Amongst them, His bundle pacing (HBP) has emerged in the past two decades as the most physiological method of ventricular pacing due to synchronous activation of both ventricles through the intrinsic conduction system. Although there is an already consistent experience in the United States, China and western Europe regarding His bundle pacing, some countries in central and eastern Europe have little or no experience in this matter. We present the results of our one-year experience after implementing His bundle pacing in a tertiary cardiac pacing center in Romania.

Material and methods

Between July 2018 and October 2019, HBP using the current available dedicated delivery system was attempted in 50 patients with permanent cardiac pacing indications. Patient characteristics and procedural results were analyzed during implant and at 3 months, 6 months and 1 year follow-ups.

Results

The mean age of the patients was 70,14 ± 10,58 years and 58 % were male. The main indication for cardiac pacing was atrioventricular block (66%) and 96 % received a dual-chamber pacemaker. No ventricular back-up leads were used. The acute procedural success (selective or nonselective His bundle capture) was achieved in 40 patients (80%). The rest of the patients received either right ventricular or left bundle branch pacing. Selective His bundle pacing was seen in 15 out of 40 patients, with nonselective His bundle pacing in the rest. The acute His pacing threshold was 1.77 ± 1.06 V at 1 ms, the sensed R wave amplitude was 4.2 ± 2.27 mV and total fluoroscopy time was 15.95 ± 10.9 min. The paced QRS duration was very similar to the baseline QRS duration in patients without bundle branch block and significantly narrower in patients with bundle branch block morphology (126,6 ± 23 ms vs. 95,5 ± 21,65 ms,  p &lt; 0,001). The presence of a native QRS complex with a bundle branch block morphology was associated with an increased risk of procedural failure, longer fluoroscopy times and higher capture thresholds. Also, pacing threshold (1,91 ± 1,23 vs. 1,62 ± 0,84 V/1ms , p = 0,4) and fluoroscopy times (21,15 ± 10,35 vs. 10,75 ± 8,85 min, p = 0,002) were lower in the second half of the procedures as the learning curve was achieved.  There were no significant changes in pacing and sensing thresholds at 3 months, 6 months and 1 year follow-ups. There was only one case of lead dislodgement a week after the procedure that required reintervention.

Conclusion

His bundle pacing is feasible and easy to implement in an experienced device implantation center, with a high procedural success rate. Improvement of the procedural parameters is achieved while advancing the learning curve. Proper patient selection could influence the outcomes of the procedure.