Almost zero-fluoroscopy LBBP-procedure using a 3D-mapping system

Introduction

Cardiac device therapy has recently been extended by the option of Conduction System Pacing, CSP (HIS Bundle Pacing, HBP; Left Bundle Branch Area Pacing, LBBAP). Similar to cardiac resynchronization therapy (CRT), complex procedures can result in long fluoroscopy-duration and considerable radiation exposure for the patient and the implanting team. According to the principle ALARA (As Low As Reasonably Achievable), measures should be taken to reduce radiation, wherever possible.

We report the almost fluoroscopy-free implantation of a LBBAP-system using a 3D electroanatomical mapping system (EAMS).

The patient was indicated for a pace & ablate concept due to recurrent, highly symptomatic, persistent atrial fibrillation (AF), a history of mitral valve repair and a severely dilated left atrium. ESC guidelines suggest choosing a RV-lead (indication IIa), alternatively either a CRT system or HBP (both IIb). LBBAP as new option for physiological pacing was chosen in this patient because it usually provides excellent stimulation thresholds and the lead – in contrast to HBP – is distant from Koch's triangle, so that AV-nodal-ablation can be performed safely.

Methods

Surgery was performed under deep sedation. After accessing the cephalic vein, a quick 3D map of relevant structures was acquired (right atrium; coronary sinus; HIS; interventricular septum, IVS). Then a preformed sheath and a stylet-driven pacemaker-lead were advanced. The lead-tip was visualized within the EAMS and maneuvered without fluoroscopy. After approaching the proximal IVS, the implantation site was confirmed by unipolar stimulation and the lead was advanced into the IVS under close monitoring of impedance and signals. Final position was confirmed by sheath-angiography [Fig. 1].

Results

During lead fixation, LBBAP-typical ECG-changes (progression to rSR morphology, fixation beats) could be observed. A left bundle branch potential (poLBB) could be documented. The left ventricular activation time (LVAT) as a marker of rapid LV-excitation was shortened from 108 ms to 68 ms. Thresholds for non-selective and selective LBBP were 3 V @ 1 ms and 0.7 V @ 0.4 ms, with a sensing of 8.7 mV, impedance of 643 ohms and a paced QRS-width of 112 ms [Fig. 2]. An atrial lead was added (history of intermittent sinus rhythm) and a dual-chamber pacemaker was connected. Fluoroscopy was required for lead fixation into the IVS, atrial lead placement as well as for sheath angiography and lead length-optimization. Total fluoroscopy time was 1.13 minutes with a radiation dose of 45.04 μGy m2, procedure time 64 minutes. AVN total ablation was performed the following day without complications.

Conclusions

CSP using a 3D mapping system is simple, facilitates understanding of important anatomical structures and helps to reduce the required radiation dose to a necessary minimum. In individual cases, procedures requiring almost zero-fluoroscopy are possible.

Funding Acknowledgement

Type of funding sources: None.

Bipolar ablation of refractory ventricular arrhythmias using a novel dedicated adapter. A multicenter study

Background

Bipolar ablation (BA) recently emerged as an alternative for treatment of ventricular tachycardia (VT) and premature ventricular contractions (PVC) refractory to a classic unipolar ablation (UA). Data on the use of available BA systems is lacking.

Purpose

To determine feasibility, safety and efficacy of a novel BA adapter in consecutive patients with refractory VT/PVC undergoing repeat ablations.

Methods

The study group consisted of consecutive patients with VT/PVC after failure of at least one standard UA who underwent redo procedures performed with a support of BA at six European centers. A second ablation catheter was connected in the position of a return electrode using a novel BA adapter.

Results

Between March 2021 and March 2022 a total number of 19 patients after failed ablation attempts underwent redo procedure using a novel BA adapter (17 males, age 61±11, number of prior ablation attempts 2,5±1,6; range 1–7). The main indication for redo ablation was recurrence of frequent PVC (n=10), VT (n=8) or electrical storm (n=1). Fifteen patients underwent combined UA+BA procedure during redo ablation, whereas 4 remaining patients underwent BA only. Two patients required epicardial access. Mean procedural time was 157±77 minutes. The mean BA time was 367±245s (power 32±9W) and mean UA time was 349±290s (power 43±6W). Apart from 1 anticipated AV block there were no major complications. Minor complications included char formation at 8mm tip electrode and steam pop without sequalae in one VT patient. BA+UA led to acute elimination of clinical PVC/VT in 18 patients. In the remaining 1 patient no effect on clinical VT during UA+BA was observed. The follow up lasted 4±3 months. Six (75%) VT patients remained arrhythmia-free and significant PVC burden reduction was achieved in nine (90%) PVC patients during follow-up. One patient treated for electrical storm experienced a single VT episode after 11 months. One patient after initially failed UA+BA underwent successful bipolar reablation after 2 months.

Conclusions

Bipolar ablation of refractory ventricular arrhythmias using a novel dedicated adapter is feasible, seems safe and effective. These encouraging preliminary results need to be confirmed in properly designed prospective trials.

Funding Acknowledgement

Type of funding sources: None.

Prevalence of silent atrial fibrillation in high-risk patients - preliminary results from a European three-country handheld ECG-screening study

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Helsefonden Lilly and Herbert Hansens Foundation

Introduction

Patients with atrial fibrillation (AF) should in most cases be offered prophylactic anticoagulation treatment to prevent a stroke. However, the arrhythmia can appear without symptoms, so-called silent AF. Even without symptoms AF constitutes a risk for stroke.

Purpose

To screen high-risk patients with diabetes type 2 (DMII) or heart failure (CHF) for silent AF.

Methods

We included patients > 64 years with either DMII or CHF from out-patient clinics and local health centers. Exclusion criteria were known AF, anticoagulation treatment, recent stroke, or an implanted pacemaker or ICD. Patients were recruited from a total of eleven study centers in three countries. All underwent 14-days of intermittent ECG screening with a handheld ECG recording four times each day; the recordings were digitally stored. AF was diagnosed in cases of irregular heart rhythm and absence of P waves on at least one recording (thirty seconds) or on at least two recordings for a minimum of ten seconds.

Results

In total, 813 patients were included, 541 of these with DMII. The mean age was 73,4 years ± 5,8 SD, 40,7% of the patients were female.

In the DMII group thirteen patients (2.4%) were diagnosed with silent AF and offered anticoagulation. In the CHF group six (2.2%) patients had diagnosed silent AF on the handheld ECG. The prevalence of AF increased with increasing age, see Table 1. Thus, in the youngest group AF was diagnosed in 1.3% of the patients compared to 3.9 % in the age group 75 years or older.

Conclusions

Screening for silent AF in high-risk patients with DMII or CHF seems worthwhile, especially in patients 75 years or older. Abstract Figure. ECG with atrial fibrillation

P472Cerebral thromboembolic risk in atrial fibrillation ablation: a direct comparison of vitamin K antagonists versus non-vitamin K-dependent oral anticoagulants

Aims

Cerebral thromboembolic events are well-known complications of pulmonary vein isolation (PVI) and can manifest as stroke or silent cerebral embolic lesions. Over the last years, the preferred oral anticoagulation in atrial fibrillation (AF) shifted from vitamin K antagonists (VKA) to non-vitamin K-dependent oral anticoagulants (NOAC). The aim of this study was to compare the incidence of cerebral embolic lesions after AF ablation in patients on VKA versus patients on NOAC, and to identify corresponding clinical and procedural risk factors.

Methods

A total of 421 patients undergoing PVI (by radiofrequency catheter or cryoballoon) were prospectively included into the study. Of these, 43.7% were on VKA and 56.3% on NOAC treatment. In the NOAC group 38% of patients had an interruption of anticoagulation for 24-36 hours. All patients underwent pre- and postprocedural cerebral magnetic resonance imaging.

Results

Periprocedural cerebral lesions occurred in 13.1% overall. Of these, three (0.7%) resulted in symptomatic cerebrovascular accidents. Incidence of cerebral lesions was significantly higher in patients on NOAC compared to VKA (16% vs. 9.2% respectively, p = 0.04), as well as in patients that had intraprocedural cardioversions compared to no cardivoersions (19.5% vs. 10.4% respectively, p = 0.03). In multivariate analysis both parameters were found to be independent risk factors for cerebral embolism. No significant difference between interrupted and uninterrupted NOAC administration could be detected.

Conclusions

In patients undergoing AF ablation, we identified the use of NOAC and intraprocedural cardioversion as independent risk factors for the occurrence of periprocedural cerebral embolic lesions.

Abstract Figure. Incidence of cerebral embolic lesions

P1022Upstream therapy using preoperative renin-angiotensin system inhibitors in prevention of postoperative atrial fibrillation and adverse events: a collaborative pooled-analysis over 27,000 patients

Background

Renin-angiotensin-system inhibitors (RASIs) have been suggested as an upstream therapy for selected AF patients; however, the evidence in surgical setting is limited.

Objective

We aimed to evaluate the role of preoperative RASIs in prevention of postoperative atrial fibrillation (POAF) and adverse events for patients undergoing cardiac surgery.

Methods

In this collaborative pooled-analysis, both randomized and nonrandomized controlled trials comparing preoperative RASIs with no preoperative RASIs treatment on the incidence of POAF were identified. Sensitivity and subgroup analyses of RCTs were performed to test the stability of the overall-effect, and meta-regression to explore the potential risk of bias. The primary outcome was POAF, and the secondary outcomes includes rate of stroke, mortality and duration of hospitalization.

Results

Eleven trials involving 27885 patients (male 74%, median age 65yrs) were included. As compared to the control group, preoperative RASIs did not significantly reduce the risk of POAF (OR: 1.04, 95% CI: 0.91–1.19), stroke (OR: 0.86, 95% CI: 0.62–1.19), death (OR: 1.07, 95% CI: 0.85–1.35), composite adverse cardiac events (OR: 1.04, 95% CI: 0.91–1.18), and hospital stay (WMD: −0.04, 95% CI: −1.05 to 0.98). Pooled-analysis of randomized trials showed consistent results. The primary overall-effect was maintained in sensitivity and subgroup analyses. Meta-regression showed that male-gender was a significant risk-factor of POAF and use of Beta-blockers was associated with a significantly reduced risk in developing POAF.

Conclusion and relevance

This study demonstrates that preoperative RASIs do not offer additional benefit in reducing the risk of postoperative AF, stroke, death and hospitalization in the setting of cardiac surgery. The results provide no support for use of RASIs for the prevention of POAF and adverse events in patients undergoing cardiac surgery.

P2844Novel temperature guided irrigated ablation catheter: reproducibility of procedural efficiencies and acute success to isolate the pulmonary veins from two multicenter, feasibility studies

Background/Introduction

The novel catheter with 6 thermocouples for real-time temperature monitoring during irrigated radiofrequency ablation was designed to potentially enhance safety and effectiveness of the Smart Touch Surround Flow (STSF) catheter by incorporating real-time temperature sensing. A supplementary, novel algorithm was developed to modulate power to maintain target temperature during high power/short duration ablation (90W, 4s).

Purpose

This sub-analysis was performed to examine consistency and reproducibility of the procedural efficiencies and acute success of the novel catheter with optimized temperature control and microelectrodes in treating paroxysmal atrial fibrillation (PAF) across multiple sites from two initial feasibility studies, in standard (QMODE) and high power/short duration (QMODE+) temperature-control ablation modes.

Methods

The QDOT-MICRO (QMODE, NCT02944968; N=42) and QDOT-FAST (QMODE+, NCT03459196; N=52) studies were both prospective, non-randomized multi-center, clinical investigations completed across 6 and 7 centers, respectively, in Europe. Procedural efficiencies and acute success (PVI via entrance block) was examined across sites within the study.

Results

In the QDOT-MICRO study, median procedure time (105–155 min), RF ablation time (27.7–39.5 min), and fluoroscopy times (2.2–8 min) during QMODE ablation were similar across the 6 sites. In QMODE+ ablation, median procedure time, RF ablation time, and fluoroscopy times all fall within (84–134 min), (4.8–9.7 min) and (1.1–9.6 min), respectively, across the 7 sites. Fluid delivery by the study catheter was low in both studies: QDOT-MICRO 547±278mL (mean ± SD); QDOT-FAST 382±299. mL (mean ± SD); which is 39.1 and 57.4% lower, respectively, than reported in the SMART SF trial. Esophageal temperature probe was used in the majority of patients (30/42 for QDOT MICRO and 51/52 for QDOT-FAST). Acute PVI was successful in 100% of patients in both studies with no deaths or unanticipated AEs.

Conclusion(s)

In both feasibility studies, procedural efficiencies were reproducible across study sites in both QMODE and QMODE+, with 100% acute success and good safety outcomes. Efficiencies are likely to improve with further experience. These results need to be confirmed in larger trials.

Acknowledgement/Funding

Both Studies are Company Sponsored Studies funded by Biosense Webster, Inc.