His bundle pacing, selective and non-selective: are they equally safe and effective?

Background

Permanent His Bundle Pacing (HBP) is the most physiological form of ventricular pacing. His bundle stimulation can be selective (s-HBP) or non-selective (ns-HBP). Few comparative data in terms of safety and efficacy among the two are available in literature.

Purpose

Evaluate the safety and efficacy of s-HBP and ns-HBP stimulation and identify predictors of one or the other stimulation.

Methods

Prospective analysis of patients with HBP implanted between December 2018 and July 2021. The clinical and instrumental parameters were collected at implant and at long-term follow-up. Follow-up data were collected both at outpatient visits and by remote monitoring systems.

Results

130 patients in need for antibradyarrhythmia therapy and 26 patients with an indication for cardiac resynchronization therapy were enrolled, 134 (86%) had successful HBP (34% s-HBP and 66% ns-HBP). There were no significant clinical differences between the two populations with the exception of the presence of right bundle branch block (RBBB: 17.4% s-HBP and 34.1% ns-HBP; p = <0.05) and baseline QRS duration (116.5±27.5 ms in s-HBP and 129.9±34.7 ms in ns-HBP; p = <0.05). There were no significant predictors of ns-HBP (Figure 1). At implantation and at an average 16-month follow-up there were no significant differences in the electrical parameters between the two HBP stimulation modalities.

Twenty-one patients (15.7% of the population, 24% of s-HBP and 12.5% of ns-HBP; p=0.38) had conduction system disease progression, manifested either by a significant increase in pacing threshold (13.3% of s-HBP and 10.2% of ns-HBP recipients; p=0.64; Figure 2A) or by loss of capture (6.5% of s-HBP and 2.2% of ns-HBP recipients; p=0.69). No statically significant predictors of conduction system disease progression were found (Figure 2B). While seventeen patients who had significant threshold elevation underwent device output reprogramming, four patients, who lost capture, and a single one experiencing lead dislodgment (nS-HBP patient) required lead repositioning (8.7% of s-HBP and 4.5% of ns-HBP recipients; p=0.33). s-HBP was significantly more vulnerable to atrial oversensing that required sensitivity reprogramming (17.4% of s-HBP and 4.5% of ns-HBP recipients; p<0.05).

No significant differences in clinical endpoints (cardiovascular death, heart failure, atrial fibrillation, syncope) were observed at follow-up.

Conclusions

In patients indicated to ventricular stimulation, the potential benefit represented by HBP is burdened by a non-negligible number of complications. Though no significant differences were detected at medium-long term between s-HBP and ns-HBP stimulation, s-HBP stimulation appears to be more affected by pacing threshold increase and progression of conduction tissue disease, which resulted in an almost 2-fold (although statistically not significant) incidence of repeated surgery.

Funding Acknowledgement

Type of funding sources: None.

Is less always more? A prospective two-centre study addressing clinical outcomes in leadless versus transvenous single-chamber pacemaker recipients

Background

Transvenous (TV) pacemakers are a well established treatment of bradyarrhythmias yet their complications, namely bleeding, infection and pneumothorax, still pose challenges to modern cardiology. This applies particularly to the older patient subgroup requiring single-chamber pacing due to comorbid atrial fibrillation (AF). Furthermore, conditions such as superior venous access issues, high infectious, or bleeding risk may complicate or preclude transvenous lead implantation. While VVIR leadless (LL) pacemakers aim to tackle these shortcomings, a comparison with contemporary single-chamber TV cohorts is currently lacking thus hindering a clear definition of the scope of LL pacing in clinical practice.

Purpose

To prospectively analyse survival and complication rates in leadless versus transvenous single-chamber pacemaker recipients.

Methods

This is a prospective analysis of 344 consecutive patients who received single-chamber TV or LL pacemakers between June 2015 and May 2021 in two tertiary cardiology centres. Indications for single-chamber pacing were “slow” AF, atrio-ventricular block with comorbid AF (either permanent or accepted as “destination rhythm”) or with sinus rhythm in bedridden cognitively impaired patients. LL indications were ongoing or expected chronic haemodialysis (6.9%), superior venous access issues such as occlusion (11.1%) or need for its preservation (9.7%), active lifestyle with low amount of pacing expected (22.2%), frailty causing high bleeding and infectious risk (23.6%), as well as recent valvular endocarditis (2.8%) or implantable electronic device infection requiring extraction (5.6%).

Results

72 patients (20.9%) received LL and 272 (79.1%) TV single-chamber pacemakers. In keeping with LL indications, diabetes and ongoing haemodialysis were more prevalent in the LL population. No significant difference in overall complication rate was observed between LL and TV patients (5.6% vs. 5.1%, p=0.33) apart from haematomas, which occurred more frequently in the LL population. Only 1 haematoma in the TV group required surgical reintervention. TV recipients survival was lower with greater cardiovascular mortality, likely due to selection of significantly older patients.

Conclusions

Given the limited complication rate observed in this contemporary single-chamber TV cohort and low life expectancy of this particular population, extending LL indications to all VVIR candidates is unlikely to provide a clearcut survival advantage. Considering the higher costs of LL technology, these data prompt a careful selection of those cases where LL approach does indeed provide an advantage. In addition to the setting of vascular access issues and high bleeding or infectious risk, these may include patients with sufficient life expectancy where lead-related risks may indeed adversely affect prognosis. Based on our patient selection criteria, LL might account for approximately 20% of VVIR pacing recipients.

Funding Acknowledgement

Type of funding sources: None.

Rapid mode in novel generation visually guided laser balloon system: feasibility, safety, and impact on procedural outcomes

Funding Acknowledgements

Type of funding sources: None.

Background

Laser balloon (LB) systems are increasingly used for pulmonary vein isolation (PVI) in catheter ablation of atrial fibrillation (AF). The novel generation of the visually guided LB system includes a rapid mode (RM) feature, which potentially allows a continuous circumferential lesion for PVI. Nevertheless, data on its practicability and on its impact on procedural outcomes are lacking.

Purpose

To analyse the applicability of RM and its effect on procedural and fluoroscopic time in a cohort of patients who underwent catheter ablation of AF using a LB system.

Methods

Between September 2020 and December 2021, we prospectively included all consecutive patients who underwent PVI with LB at our centre. All the procedures were performed by the same two operators. For each pulmonary vein (PV), we firstly attempted to obtain a complete circumferential lesion at 13 W using the RM. If its application was not possible or incomplete, we performed additional single lesions at 5.5, 8.5 or 13 W to achieve complete visual PVI. Finally, we calculated the percentage of singular and total circumferential lesions made with RM for every procedure and evaluated its influence on procedural outcomes.

Results

75 patients were enrolled. We identified and successfully isolated 289 PVs, with mean procedural and fluoroscopic time of 171±51 and 38±15 min, respectively. Use of RM for more than 70% of the circumferential lesion was possible in 185 veins (64%), while we obtained complete isolation using only RM in 90 veins (31%). Reasons for interruption of RM were unfavourable anatomy, imperfect visualization of the ostium of the PV and presence of blood between the balloon and the anatomic substrate. For each vein, we observed a significantly shorter ablation (13±8 vs 23±12 min, p<0.001) and fluoroscopic time (3±3 vs 5±4 min, p<0.01) if >70% of the circumferential lesion was made through RM. Further, total procedural (157 ±52 vs 192±42 min, p<0.01), ablation (53±17 vs 88±27, p >0.001) and fluoroscopic time (30±15 vs 36.9±14 min, p 0.025) were significantly shorter if more than 70% of total circumferential lesion was achieved through rapid mode. There were five pinhole balloon ruptures during application of RM. No major complication occurred.

Conclusions

RM is a novel feature in the latest generation of LB system. In our cohort, it showed good applicability and safety, while significantly reducing procedural times. Further studies are needed to understand its possible impact on clinical outcomes.

Implantable cardioverter defibrillator in arrhythmogenic cardiomyopathy: which role for antitachycardia pacing?

Funding Acknowledgements

Type of funding sources: None.

Background

Arrhythmogenic Cardiomyopathy (ACM) is an inherited cardiomyopathy characterized by ventricular arrhythmias and sudden cardiac death. Implantable cardioverter defibrillator (ICD) remains the only proven therapy to reduce mortality in ACM.

Purpose

The objective of this study was to identify characteristics of ventricular arrhythmias and treatment in patients with ACM.

Method

Retrospective analysis of the data of consecutives patients with confirmed diagnosis of ACM based on the proposed Padua Criteria, who underwent implantation of transvenous ICD from January 1992 and October 2021. The clinical data and information about appropriate and inappropriate ICD therapies were obtained from medical records with the review of the available intra-cardiac electrograms (EGMs).

Results

We enrolled 52 patients (69% males, mean age at implant 48.9 ±14.8 years), 27 (52%) were implanted for primary prevention, 25 (48%) for secondary prevention. After a median follow-up of 7.52 years [IQR: 4.37 - 12.0], 32 patients (61.5%) had 914 sustained episodes of ventricular arrhythmias (VA). 25 patients (48%) had 309 episodes of life-threatening arrhythmias (LT-VA), defined as sustained ventricular tachycardia ≥200 beats/min. In 29/32 patients (91%) ATP treated at least one episode of VA and in 14/25 (56%) at least one episode of LT-VA. Ventricular tachycardia (VT) detection was programmed at least 20 seconds, while VF detection was at least 7 seconds. Among patients with appropriate ICD activation, the first treated episode was a LT-VA in 50% of cases. Out of 914 VA episodes, 735 (80.4%) were treated with ATP and 179 (19.6%) with shocks. Considering LT-VA (cycle length 248 ± 25 ms), 201/309 (65%) and 108/309 (35%) episodes were treated with ATP and shocks, respectively. In 13 patients (25%) there was an inappropriate ICD activation, mostly caused by atrial fibrillation, while in 8 patients (15%) there was a complication needing reintervention (in 3 cases there was a loss of ventricular sensing dictating lead revision).

Conclusions

ACM patients are at risk of VA and LT-VA. The majority of VA at follow-up are monomorphic at rate <200 beats/minute, however the first treated VA episode is a LT-VA in half of cases. ATP is highly successful in terminating VT and even LT-VA, which questions the use of non-transvenous ICD in this young patient population. Nevertheless, transvenous ICDs are burdened by a relevant rate of lead complications which should be weighed in the choice of the ICD type.

Learning curve for laser balloon ablation in the treatment of atrial fibrillation: a single center experience

Funding Acknowledgements

Type of funding sources: None.

Background

Visually guided laser balloon ablation (LBA) is a promising method for pulmonary vein (PV) isolation in the treatment of atrial fibrillation (AF). To reduce procedural times, the rapid mode feature (RM), which offers an automated continuous 360° lesion for pulmonary vein isolation, was implemented in the latest version of the laser balloon system.

Purpose

We evaluated the learning curve for LBA in the treatment of AF

Method

We enrolled the first 74 patients with paroxysmal or persistent AF treated with LBA in our centre between September 2020 and December 2021. Exclusion criteria were any contraindication for the procedure. 3 different time intervals were considered (time 1 T1, time 2 T2 and time 3 T3), which included the first 25 patients, the next 25 patients and the last 24 patients, respectively. We compared fluoroscopy and procedural time and the number of pulmonary veins isolated by RM >90% (>324°) among the three group were compared.

Results

There was no difference between the three intervals in terms of age (61.2 ±9.00 vs 63.9 ±11.4 vs 58.4 ±12.9; p=n.s.), sex (68% vs 64% vs 81%; p=n.s.) and clinical characteristics. The procedural time (see picture 1) was significantly reduced from T1 to T2 (199 ±51.8 in T1 vs 159 ±38.6 in T2; p< 0.01), while there was no variation between T2 and T3 (159 ±38.6 in T2 vs 153 ±51.9 in T3; p=n.s.). We detected a reduction in fluoroscopy time between T1 and T2 (38.8 ±15.2 in T1 vs 28.8 ±10.5 in T2; p<0.01) but not further reduction was observed between T2 and T3 (28.8 ±10.5 in T2 vs 30.5 ±16.7 in T3; p =n.s.). Considering the use of (RM) feature, there was a progressive increase in the number of PVs isolated by RM >90% over time (1.0 ±0.7 PVs in T1 vs 2.0 ±1.2 PVs in T2 vs 3.3 ±0.9 in T3: p <0.01). Five pinhole balloon ruptures were observed, three in the T1 group, two in the T3 group. Temporary phrenic nerve dysfunction occurred in 1 patient in the T3 interval. No other complications were reported.

Conclusions

PV isolation by visually guided LBA is a safe procedure even during the learning curve. The system is user friendly and procedural time and fluoroscopy time reduced after a limited number of procedures.

Real use of a novel automatic motorized laser balloon for the ablation of atrial fibrillation

Background

Electric isolation of the pulmonary veins (PVs) can successfully treat patients with atrial fibrillation (AF). Isolation of pulmonary veins can be achieved by several methods: radiofrequency, cryoballoon or laser balloon ablation (LBA). The main procedural challenge with either method is to achieve a continuous circumferential lesion at the left atrium-PVs junction, with the persistence of functional gaps.

Purpose

A novel endoscopic ablation system equipped with a precise motor control system (MCS) has been evaluated. The balloon is used with an endoscope to directly visualize and ablate tissue at the left atrial-PVs junction with laser energy. This system enables uninterrupted, high-speed, circumferential lesion creation under direct control of the physician. The MCS is intended to reduce procedure time and to ensure continuity of ablation lesions. The feasibility of the motorized ablation in terms of extent of applicability along each PV-left atrium junction and time of use of the manual point-by-point mode has been investigated.

Methods

27 consecutive patients (male 70.3%, age 61.2±8.7 years) with paroxysmal or persistent AF who underwent LBA were enrolled in our institution. Exclusion criteria were any contraindication for the procedure including the presence of intracavitary thrombosis and contraindications to general anesthesia or deep sedation. After transseptal puncture, the balloon-based endoscopic ablation system was advanced to each PV ostium, and laser energy were projected onto the target.

Results

A total of 110 PVs were treated with LBA; in 9 patients there was a redundant right intermediate pulmonary vein; in 4 patients there was a right common ostium and in 2 a left common ostium. MCS was used for 82 PVs (74.5%): in particular, MCS was used continuously between 180° and 325° degrees (50 to 90% of PV circumference) for 35 PVs (31.8%) and between 326° and 359° degrees (91 to 99% of PV circumference) for 25 veins (22.7%). In 13 PVs (12%) MCS was used for the entire circumference. During 8508 (19.6%) seconds out of a total of 43.368 seconds, laser energy delivery occurred in the rapid mode by MCS.

No clinical complications, either local or systemic (stroke or TIA, pericardial effusion, pericardial tamponade, pulmonary vein stenosis, esophageal injury, temporary or permanent phrenic nerve palsy), were observed neither during the use of MSC nor during the use of manual point-by-point mode. Of note, a pinhole rupture of the balloon occurred in 3 cases of our series, during the use of MCS, without harm to the patient and requiring only replacement of the LBA.

Conclusions

In our case series, laser balloon ablation with the help of motor control system appears safe and feasible in most cases for large portions of pulmonary vein circumference, providing considerable time sparing (74.5% of total ablation extent in 19.6% of total ablation time).

Funding Acknowledgement

Type of funding sources: None.

Third-generation laser balloon ablation: rapid mode applicability is associated with shorter time to pulmonary vein isolation

Background

The rapid mode feature implemented in the latest version of the laser balloon system (LB3, HeartLight, X3, Cardiofocus) offers an automated continuous 360° lesion for pulmonary vein isolation (PVI). However, data on its clinical applicability and the potential reduction of procedural times are not yet available.

Purpose

To explore the use of the rapid mode and its association with PV total and fluoroscopy times in our initial experience with LB3.

Methods

This analysis included consecutive patients who underwent PVI procedure with LB3. We attempted to perform a complete circular ablation line using the rapid mode at 13 W, but if needed to achieve successful isolation, rapid mode was interrupted and manual mode (5.5–8.5 W) applications were used. The percentage of rapid mode use on the 360° lesion was measured for each PV. Total and fluoroscopy times to complete PVI were also collected.

Results

A total of 110 PVs were identified in 27 LB3 procedures and successfully isolated with a mean procedural time of 85±31 min. Sixty (55%) PVs were treated by using rapid mode for more than 50% (180°) lesion and 13 (12%) of them had a pure rapid mode ablation (without necessity of manual mode applications). Right inferior PV had the highest use of rapid mode (median value 70%). The main reasons for manual applications were poor PV occlusion, imperfect ostium visualization and presence of blood. PVs with >50% rapid mode use were treated in a significantly shorter time (21.2±13.7 vs 26.8±12.4, p=0.043). Fluoroscopy time did not differ significantly (4.7±4.2 vs 5.4±4.9, p=0.48). Three pinhole balloon ruptures were observed during rapid mode energy application in the second, third and twenty-fifth procedure. No other complications occurred.

Conclusions

Few PVs could be isolated using pure rapid mode; however, its applicability for more than 50% lesion was observed more frequently and significantly reduced the time to isolation.

Funding Acknowledgement

Type of funding sources: None. Time to isolation using Rapid Mode

Slow VT treatment in a contemporary population of primary prevention ICD recipients

Funding Acknowledgements

Type of funding sources: None.

Background

Implantable cardioverter defibrillator (ICD) is an effective therapy for sudden cardiac death (SCD). 2015 HRS/EHRA/APHRS/SOLAECE expert consensus document suggests long VT detection, above 185 bpm, as optimal ICD programming to reduce unnecessary therapies in primary prevention (PP).

Purpose

The aim of our study is to evaluate incidence, safety and efficacy of ICD treatment for VT arrhythmias below 185 bpm, in a contemporary population of PP ICD recipients with long detection intervals (LDI), morphological discrimination algorithm and antitachycardia pacing therapies (ATP) before shock.

Methods

We conducted a single centre retrospective study enrolling 236 patients implanted with a primary-prevention indication from January 2013 to June 2019. Patients were implanted with single or dual chamber single-lead transvenous ICD. All patients had standard device setting with long (at least 20 s in VT and 7 s in VF) VT/VF detection above 150 bpm and therapies starting from 171 with up to 5 ATP and multiple shocks. PainFREE-like bursts and Schaumann-like ramps ATP were always set in VT zone. Of each patient we collected a detailed report of up to five appropriate events and three inappropriate events. Arrhythmia diagnosis was confirmed from 3 independent expert physicians.  Date of the event, cycle length, type of morphology (polymorphic or monomorphic), therapies with their effect were collected.

Results

During a mean follow-up of 42 months, 47 (20 %) and 18 (8%) patients had at least one appropriate and inappropriate activation, respectively. The detailed-events analysis shows that 16 (7%) patients had 38 (30%) appropriate events with rate <188 bpm. At these rate ATP were 97% effective. 14 (38%) of inappropriate activations were caused by arrythmias with ventricular rate below 188 bpm and half of these received a shock; 30% of inappropriate shocks were due to arrhythmia with rate <188 bpm. 73% of treated events, with rate <188 bpm, were appropriate. Only 5.6% (n = 10) of ATP attempts cause arrhythmia acceleration.

Conclusions

One third of detected arrhythmias had a rate below 188 bpm and 73% were true VT. In this slow VT zone, ATP had a high success rate with low percentage of acceleration.

Real use of a novel automatic motorized laser balloon for the ablation of atrial fibrillation

Funding Acknowledgements

Type of funding sources: None.

Background

Electric isolation of the pulmonary veins (PVs) can successfully treat patients with atrial fibrillation (AF). Isolation of pulmonary veins can be achieved by several methods: radiofrequency, cryoballoon or laser balloon ablation (LBA). The main procedural challenge with either method is to achieve a continuous circumferential lesion at the left atrium-PVs junction, with the persistence of functional gaps.

Purpose

A novel endoscopic ablation system equipped with a precise motor control system (MCS) has been evaluated. The balloon is used with an endoscope to directly visualize and ablate tissue at the left atrial-PVs junction with laser energy. This system enables uninterrupted, high-speed, circumferential lesion creation under direct control of the physician. The MCS is intended to reduce procedure time and to ensure continuity of ablation lesions. The feasibility of the motorized ablation in terms of extent of applicability along each PV-left atrium junction and time of use of the manual point-by-point mode has been investigated.

Methods

sixteen consecutive patients (male 68.7%, age 60.9 ± 7.8 years) with paroxysmal or persistent AF who underwent LBA were enrolled in our institution. Exclusion criteria were any contraindication for the procedure including the presence of intracavitary thrombosis and contraindications to general anesthesia or deep sedation. After transseptal puncture, the balloon-based endoscopic ablation system was advanced to each PV ostium, and laser energy were projected onto the target.

Results

A total of 62 PVs were treated with LBA; in 3 patients there was a redundant right intermediate pulmonary vein; in 4 patients there was a right common ostium and in one a left common ostium. MCS was used for 41 PVs (66.1%): in particular, MCS was used continuously between 180° and 325° degrees (50 to 90% of PV circumference) for 22 PVs (35.5%) and between 326° and 359° degrees (91 to 99% of PV circumference) for 16 veins (25.8%).  In 3 PVs (4.8%) MCS was used for the entire circumference.  During 5.659 (23.6%) seconds out of a total of 23.986 seconds, laser energy delivery occurred in the rapid mode by MCS.

No clinical complications, either local or systemic (stroke or TIA, pericardial effusion, pericardial  tamponade, pulmonary vein stenosis, esophageal injury, temporary or permanent phrenic nerve palsy), were observed neither during the use of MSC nor during the use of manual point-by-point mode. Of note, a pinhole rupture of the balloon occurred in the first 2 cases of our series, during the use of MCS, without harm to the patient and requiring only replacement of the LBA.

Conclusions

In our case series, laser balloon ablation with the help of motor control system appears safe and feasible in most cases for large portions of pulmonary vein circumference, providing considerable time sparing (66.1% of total ablation extent in 23.6% of total ablation time).