Permanent Atrioventricular Block Research Articles

Abstract Mo072: Sustained Biological Pacemaker Activity Induced by AAV9-hTBX18

Background: Sinoatrial node (SAN) dysfunction is a clinical disorder characterized by the inability of the SAN to maintain an appropriate heart rate (HR). Patients with this condition often need an electronic pacemaker. Although it is the current standard of care, devices can have complications. A biological pacemaker has been created by adenovirus expressing TBX18 as an alternative. Hypothesis: However, adenoviruses are immunogenic, limiting the duration of expression. We hypothesized that an AAV9 would promote prolonged TBX18 expression, induce somatic reprogramming in vivo, and sustained pacemaker activity. Methods: AAV9 containing GFP or TBX18 was directly injected into the myocardium of eight-week-old male Sprague Dawley rats (n=70) at low (1x10 9 GC), mid (1x10 10 GC) and high (1x10 11 GC) doses. Transient AV block was induced by tail vein injection of adenosine. A permanent complete AV block was induced by ablation of the his bundle. Hearts were harvested for optical mapping and mRNA analysis. Results: Six weeks after injection, all doses of AAV9-TBX18 had increased HR (low: 104±4, p=0.04; mid: 106±3.4, p=0.008; high: 103±4.1, p=0.04; vs GFP: 89±3 bpm) compared to AAV9-GFP when we induced AV block using adenosine. AAV9-GFP and -TBX18 mid dose injected rats underwent surgery to induce complete AV block. TBX18 group presented superior HR over the 24 hours monitored. 6-lead EKG analysis of the QRS axis in the frontal plane revealed that the ventricular ectopic beats from the AAV9-TBX18-injected group originated from the injection site. Activation maps further confirmed that the injection site originated those beats in TBX18-injected rats only. Successful reprogramming of adult ventricular myocytes into SAN-like cells was confirmed by transcriptional profiles with increased expression of TBX18 (2.2±0.5 FC, p<0.0001) and Hcn2 (25.2±1.1 FC, p=0.02), and reduced Gja1 (-10.8±0.7 FC, p=0.005), Scn5a (-1.1±0.8 FC, p=0.01) and Nkx2.5 (-2.0±0.6 FC, p=0.004) relative to GFP. Conclusion: Collectively, these data indicate that the AAV-based somatic reprogramming induced by TBX18 leads to sustained biological pacemaker activity in rats with AV block. Long-term studies are needed to characterize the long-term effects of sustained TBX18 expression.

Elevated myocardial extracellular volume fraction is associated with the development of conduction pathway defects following transcatheter aortic valve replacement.

Transcatheter aortic valve replacement (TAVR) has become an established method of aortic stenosis treatment but suffers from the risk of heart block and pacemaker requirement. Risk stratification for patients who may develop heart block remains imperfect. Simultaneously, myocardial fibrosis as measured by cardiac magnetic resonance imaging (CMR) has been demonstrated as a prognostic indicator of ventricular recovery and mortality following TAVR. However, the association of CMR-based measures of myocardial fibrosis with post-TAVR conduction disturbances has not yet been explored. We evaluated whether myocardial fibrosis, as measured by late gadolinium enhancement and extracellular volume (ECV) from CMR would be associated with new conduction abnormalities following TAVR. One hundred seventy patients who underwent CMR within 2 months before TAVR were retrospectively reviewed. Septal late gadolinium enhancement (LGE) and ECV measurements were made as surrogates for replacement and interstitial fibrosis respectively. New conduction abnormalities were defined by the presence of transient or permanent atrioventricular block, new bundle branch blocks, and need for permanent pacemaker. Association of myocardial fibrosis and new conduction derangements were tested using receiver operator curve (ROC) and regression analysis in patients with and without pre-existing conduction issues. Forty-six (27.1%) patients developed post-TAVR conduction deficits. ECV was significantly higher among patients who experienced new conduction defects (26.2 ± 3.45% vs. 24.7% ± 4.15%, p value: 0.020). A greater fraction of patients that had new conduction defects had an elevated ECV of ≥26% (54.3% vs. 36.3%, p value: 0.026). ECV ≥ 26% was independently associated with the development of new conduction defects (odds ratio [OR]: 2.364, p value: 0.030). ROC analysis revealed a significant association of ECV with new conduction defects with an area under the receiver operating characteristic curve (AUC) of 0.632 (95% confidence interval: 0.555-0.705, p value: 0.005). The combination of prior right bundle branch block (RBBB) and ECV revealed a greater AUC of 0.779 (0.709-0.839, p value: <0.001) than RBBB alone (Delong p value: 0.049). No association of LGE/ECV with new conduction defects was observed among patients with pre-existing conduction disease. Among patients without baseline conduction disease, ECV was independently associated with the development of new conduction deficits (OR: 3.685, p value: 0.008). The present study explored the association of myocardial fibrosis, as measured by LGE and ECV with conduction deficits post-TAVR. Our results demonstrate an association of ECV, and thereby interstitial myocardial fibrosis, with new conduction derangement post-TAVR and introduce ECV as a potentially new risk stratification tool to identify patients at higher risk for needing post-TAVR surveillance and/or permanent pacemaker.

КАРДИОНЕЙРОАБЛАЦИЯ – ФИЗИОЛОГИЧЕСКИЕ ОСНОВЫ МЕТОДА, КЛИНИЧЕСКОЕ ПРИМЕНЕНИЕ ПРИ НАРУШЕНИЯХ РИТМА СЕРДЦА

Increased tone of the parasympathetic part of the autonomic nervous system, affecting the pacemaker cells, may cause sinus bradycardia, develop long pauses of heart rhythm, paroxysmal or permanent atrioventricular block followed by reflex syncope. The usual reflex syncope treatment is conservative and includes avoiding situations that trigger syncope (prolonged standing, sight of blood etc.), tilt-training, adequate drinking regime, wearing compression underwear, sleeping with the head of the bed elevated and in some cases stimulating neuro- and vegetotropic therapy. Some patients are refractory to conventional methods of treatment and retain severe symptoms that worsens quality of their life seriously. These patients may be required a pacemaker implantation subsequently. Cardioneuroablation is an alternative treatment in patients with overactive parasympathetic nervous system that is based on radiofrequency catheter ablation of the major parasympathetic autonomic ganglia around the heart.

Comparison between cryotherapy and radiofrequency energy sources for parahisian accessory pathway percutaneous ablation.

Catheter ablation of parahisian accessory pathways (PHAP) are challenging due to their proximity to the normal conduction system. Retrospective studies suggest that cryoablation has a better safety profile but a higher recurrence rate when compared to radiofrequency ablation (RFCA). The objective of this study was to compare the results of parahisian AP ablation performed by electrophysiologists with experience in both technologies. Prospective single-center, non-blinded and 1:1 model was used. Patients included had parahisian AP confirmed by an electrophysiological study and referred for radiofrequency or cryotherapy ablation according to current guidelines, under fluoroscopic guidance. No electroanatomic mapping was used. A total of 30 patients (mean age of 25±9.4 years; 90% male) were enrolled between Oct/2018 to Feb/2020. Acute success rate between RFCA and CRYO were similar (93% vs. 87%, p = 0.54). A nonsignificant reduction in short-term recurrence rate for RFCA (14% vs. 30%, p = 0.3) and mechanical trauma (6% vs. 20%; p = 0.28) was observed. Long-term recurrence rate and event-free survival time were similar in both groups after 1-year follow-up (p = 0.286). No persistent complete AV block or conduction disturbance was also observed. Considering the limitation of a small sample size and the lack of use of electroanatomic mapping for RFCA, the efficacy and safety profile of parahisian AP ablation with RFCA was not different from CRYO, when performed by experienced electrophysiologists. No cases of permanent complete AV block were reported with either energy modalities.

Clinical Characteristics and Comparative Proteomics Analysis of COVID-19-Related Atrioventricular Block.

Atrioventricular block (AVB) is thought to be a rare cardiovascular complication of the coronavirus disease 2019 (COVID-19), though limited data are available beyond case reports. We aim to describe the baseline characteristics, proteomics profile, and outcomes for patients with COVID-19-related AVB. We prospectively recruited patients diagnosed with COVID-19-related AVB between November 2022 and March, 2023. Inclusion criteria were hospitalization for COVID-19 with the diagnosis of AVB. A total of 24 patients diagnosed with COVID-19 without AVB were recruited for control. We analyzed patient characteristics and outcomes and performed a comparative proteomics analysis on plasma samples of those patients and controls. A total of 17 patients diagnosed with COVID-19-related AVB and 24 individuals diagnosed with COVID-19 infection without AVB were included. Among patients with COVID-19-related AVB, the proportion of concurrent pneumonia was significantly higher than controls (7/17 versus 2/24, p 0.05). All 17 AVB patients (9 of permanent AVB, 8 of paroxysmal AVB) received permanent pacemaker implantation. No procedural-related complication occurred. In laboratory tests, the level of biomarkers indicating myocardial damage were substantially higher than controls, including high-sensitivity cardiac troponin-I (median 0.005 versus 0.002 ng/mL, p 0.05), myoglobulin (median 39.0 versus 27.6 ng/mL, p 0.05), and MB isoenzyme of creatine kinase (median 1.2 versus 0.8 U/L, p 0.05). The level of N-terminal pro-b-type natriuretic peptide (median 241.0 versus 33.5 pg/mL, p 0.05), C-reactive protein (median 4.8 versus 2.0 mg/L, p 0.05), D-dimer (median 1.2 versus 0.2 µg/mL, p 0.05), left ventricular end-diastolic diameter (median 49.3 versus 45.7 mm, p 0.05) in patients with COVID-19-related AVB were significantly higher than controls. The level of albumin (median 41.9 versus 44.5 g/L, p 0.05) was significantly lower than controls. In comparative proteomics analysis, we identified 397 human proteins. Several significantly altered plasma proteins related to inflammatory response (Serum amyloid A protein, C-reactive protein, Protein Adenosine 5'-monophosphate-activated protein kinase (AMPK), Alpha-2-macroglobulin), complement and coagulation cascades (Tetranectin, haptoglobin), and immune response (Neutrophil defensin 3, Fibrinogen beta chain) may contribute to the pathogenesis of COVID-19-related AVB. Patients with COVID-19-related AVB are more prone to have myocardial damage and concurrent pneumonia. Through laboratory tests and comparative proteomics analysis, we identified several differential expressed proteins (Serum amyloid A protein, Tetranectin, Neutrophil defensin 3) releated to the inflammatory response, complement and coagulation cascades, and immune response, which provides evidence of potential biomarkers and sheds light on the pathogenesis of COVID-19-related AVB.

Trans-catheter cryoablation of parahisian accessory pathways: a single centre experience

Abstract Introduction Transcatheter radiofrequency (RF) ablation of perinodal accessory pathways (parahisian/midseptal APs) is still challenging especially in young patients due to a high risk for inadvertent atrioventricular block (AVB) requiring permanent pacing. Recently, cryo-ablation (CA) has evolved as an RF alternative, thanks to a safer profile and a better catheter stability. Purpose To evaluate the safety, efficacy and outcomes of CA in patients with parahisian/midseptal APs. Methods 73 pts undergoing a first ablation of septal APs at our institution were retrospectively analyzed. Among these, we selected 20 patients with a diagnosis of para-hisian/midseptal AP confirmed by EP study (EPS) and 3D-electro-anatomic mapping (EAM), ablated using cryoenergy. Before delivering CA, a cryomapping (CM) at the target AP site was performed at −30°C using a 6- mm-tip catheter. Successful CM was defined as: (1) loss of delta wave in case of manifest pre-excitation, (2) termination of a sustained AVRT, (3) retrograde conduction block through the AP during ventricular pacing in case of concealed AP. CA was initiated following successful CM, at a temperature of −75°C for 300 s with an additional "bonus" CA application (300s). Acute procedural endpoint was permanent complete abolition of AP conduction; long-term clinical endpoint was defined as no recurrence of delta wave or AVRT on serial ECG monitoring at follow-up (1, 6, 12 months). RESULTS Baseline characteristics are summarized in Fig. 1. Fifty-five % were pediatric patients, only 3/20 presented a structural HD. Up to 90% of the patients experienced a symptomatic AVRT, while delta-wave was present at baseline ECG in 19/20 patients. EPS combined with 3D-EAM showed a para-hisian AP in 80% and a mid-septal AP in 20%. Mean distance between His bundle electrogram and AP site was 5.72 mm (4-6.8 mm, Fig. 2). Orthodromic AVRT was induced in all the 20 pts. Maen procedural and fluoroscopy times were, respectively, 103.4 ± 26.4 and 3.15± 1.76 min . Acute success was achieved in 20/20 patients (100%) with AP block of conduction obtained within few seconds (&amp;lt;10s) after a mean CM number of 3.3 ± 1.2 (Fig. 2). Two patients developed transient 2:1 AV block and 1 patient transient RBBB during CM, with immediate recovery within 20s from CM termination. No peri-procedural complications or permanent AV block were observed. One patient had an early AP re-conduction (6 hours later) and was successfully re-ablated the following day. During a mean FU of 361 ± 34 days, only two patients (10%) experienced an AVRT recurrence and underwent a second successful CA. Conclusions Cryoablation of parahisian and midseptal APs is a safe and effective alternative to RF, resulting in a low risk of recurrence over 12-months-follow-up with no incidence of permanent AV block. A near-zero fluoroscopy approach combining CA and 3D-EAM is feasible and should be considered especially in very young patients with parahisian APs.Fig. 1Fig. 2

Very early fractures of the stylet-driven Biotronik Solia lead used for left bundle branch area pacing

Abstract Introduction Left bundle branch area pacing (LBBAP) has become increasingly popular due to the relatively simple implantation procedure allowing for conduction system pacing (CSP). Initially, lumen-less leads have been used primarily for CSP. However, several authors have published encouraging results using conventional stylet-driven pacemaker (PM) leads as well and our centers have largely adopted this approach. Methods In our two tertiary referral centers, we assessed all patients, who underwent a LBBAP lead implantation using any lead. We observed several early lead fractures, exhibiting a unique failure mechanism, which we illustrate in this case-series. Results Between January 2022 and November 2023 343/393 patients (87.3%) were implanted with a Solia pacemaker lead, 46/393 (11.7%) received a SelectSecure 3830 lead, and 4/393 (1.0%) another stylet-driven lead. Three patients (0.8%) who initially were implanted with a Solia lead experienced very early intracardiac lead fractures within 1, 11 and 13 months after implantation despite good initial electrical performance values (Table shows initial values and values during the time of failure (bold)). The first case was a 54 year-old woman with permanent 3d degree AV block receiving an LBBAP lead after lead extraction. Four weeks later, she presented with presyncope and exit block at maximum output in uni- and bipolar configuration. The second case was a 72 year-old man with intermittent 3rd degree AV block in the context of an ischemic heart disease. He received a dual-chamber LBBAP PM. 13 months after the implantation, a bipolar impedance &amp;gt; 2’500Ω and exit block were noted. The third case was 65 year-old man suffering from sick sinus syndrome. He initially underwent a dual-chamber PM implantation in 2011 and due to ventricular sensing issues a transvenous lead extraction and implantation of a LBBAP lead in October 2022. During device follow-up after 11 months, a fractured LBBAP lead with bipolar impedance &amp;gt;2’500Ω and exit block during threshold testing was noticed. In all cases, X-rays and macroscopic analysis consistently showed a disintegration of the lead immediately distal to the ring electrode (Figure; site of fracture marked with an arrow). Most likely, this was caused by the repetitive shear stress at the hinge point of the lead where it is entering the septum. Conclusion No dedicated stylet-driven CSP lead is available to date. The implantation site and technique for LBBAP may exert higher mechanical stress on the distal part of the lead, making it more prone to fracture than in a conventional position. Currently, the use of conventional stylet-driven leads is still off-label and the performance of such leads should be monitored closely.TableFigure

DECENNIAL ANALYSIS OF AVNRT ABLATION IN A SINGLE CENTRE

Abstract Background Transcatheter ablation represents the first line therapy for atrio–ventricular nodal re–entrant tachycardia (AVNRT). Both radiofrequency (RF) and cryoablation (CRYO) have been shown to be effective, with a better safety profile for CRYO. Data on very long–term efficacy are scarces. Purpose To review our experience in AVNRT ablation performed in the last ten years and evaluate safety, efficacy and very long–term outcome of RF and CRYO. Methods We retrospectively analyzed all patients who underwent AVNRT ablation (RF or CRYO) between January 2013 and May 2023 at our centre. The majority of procedures were performed under electro–anatomical mapping (EAM) guidance to reduce radiation exposure. Acute efficacy endpoint was defined as slow pathway ablation, while long–term outcome was defined as the absence of AVNRT recurrence. Results A total of 387 consecutive patients (60,5% F; mean age 48 ± 19 years) were included; CRYO was performed in 241 patients (62%), RF in 131 patients (34%), hybrid approach (CRYO+RF) in 15 patients (4%). AVNRT induction was obtained during EPS in 295 cases (76%), in 25,4% after isoprotenerol administration. No significant differences for baseline characteristics were observed between the two groups except for age (CRYO: 42,2 ± 18 years vs RF 57,19 ± 16,5 years p &amp;lt;0.001). In pediatric population CRYO was performed in 93% of procedures. Figure 1 shows the distribution of RF/CRYO over 10 years at our centre, with a trend of significant increase in CRYO utilizations in the last years. Acute success was achieved in all 387 cases (100%; delta WP 28,5 ± 23,1 ms, delta AVN ERP 72,4 ± 44,7 ms). No permanent AV block or major periprocedural complications occurred, however transient AH prolongation was observed in 0.8% in CRYO pts vs 2,8% RF pts. The mean follow–up was 73±45 months, range 6–129 months. Overall long–term success rate was 93,3%, ranging from 91,3 % in CRYO and 96,6% in RF. Recurrence occurred in 26 cases (6,7%) after a median time of 20 months (4–40months). Recurrent AVNRT were treated with RF in the majority of cases, CRYO in 6 procedures, hybrid in only 1 case. Conclusions Transcatheter ablation is a safe and effective therapy for AVNRT. Our very long–term outcome data confirmed very high success rate even after 10 years follow–up. The increasing choice for CRYO may be due to the increasing number of pediatric and young patient referred to our centre.

Ten-Year Experience with Endomyocardial Biopsy after Orthotopic Heart Transplantation: Comparison between Trans-Jugular and Trans-Femoral Approach.

Endomyocardial biopsy (EMB) is considered the gold standard for monitoring allograft rejection after heart transplantation. EMB is an invasive procedure that may be performed via a trans-jugular or a trans-femoral approach with a complication rate reported as less than 6%. The aim of this study was to evaluate the complication rate after EMBs in heart recipients and to compare the results of EMBs performed via a trans-jugular or a trans-femoral approach. Medical records of heart recipients undergoing EMBs between January 2012 and December 2022 were retrospectively reviewed. EMB-related complications were classified as major (death, pericardial effusion, hemopericardium, cardiac tamponade requiring a pericardiocentesis or an urgent cardiac surgery, ventricular arrythmias, permanent atrio-ventricular block requiring permanent pacing, hemothorax, pneumothorax and retroperitoneal bleeding) and minor (de novo tricuspid regurgitation, arrhythmias, coronary artery fistula, vascular access site complications). A total of 1698 EMBs were performed during the study period at our institution in 212 heart recipients. There were 927 (55%) EMBs performed through a trans-jugular approach (TJ group) and 771 (45%) EMBs performed through a trans-femoral approach (TF group). A total of 60 (3.5%) complications were recorded, including nine (0.5%) major complications (six cardiac tamponades, two pneumothorax and one retroperitoneal bleeding) and 51 (3%) minor complications (seven coronary fistulae, five de novo tricuspid regurgitation, four supraventricular arrythmias and thirty-five vascular access site complications). No difference was found in total (38 [4%] vs. 22 [3%]; p = 0.16) and major (6 [1%} vs. 3 [0.4%]; p = 0.65) complications (32 [3%] vs. 19 [2%]; p = 0.23) between the TJ group and the TF group. No difference was found in male sex, age at time of EMB and time from HT between complicated and not complicated EMBs. EMBs represent a safe procedure with a low risk of complications. In our experience, EMBs performed via a trans-jugular approach are as safe as the trans-femoral approach.

Relationship between the atrial-activation pattern around the triangle of Koch and successful ablation sites in slow-fast atrioventricular nodal reentrant tachycardia.

The precise details of atrial activation around the triangle of Koch (ToK) remain unknown. We evaluated the relationship between the atrial-activation pattern around the ToK and success sites for slow-pathway (SP) modification ablation in slow-fast atrioventricular reentrant tachycardia (AVNRT). Thirty patients with slow-fast AVNRT who underwent successful ablation were enrolled. Atrial activation around the ToK during sinus rhythm was investigated using ultra-high-density mapping pre-ablation. The relationships among features of atrial-activation pattern and success sites were examined. Of 30 patients (22 cryoablation; 8 radiofrequency ablation), 26 patients had a collision site of two wavefronts of delayed atrial activation within ToK, indicating a success site. The activation-search function of Lumipoint software, which highlights only atrial activation with a spatiotemporal consistency, showed non-highlighted area on the tricuspid-annulus side of ToK. In 23 of the patients, a spiky potential was recorded at that collision site outside the Lumipoint-highlighted area. Fifteen cryoablation patients with a success site coincident with a collision site outside the Lumipoint-highlighted area had significantly more frequent disappearances of SP after initial cryoablation (46.7% vs. 0%, p = .029), fewer cryoablations (3.7 ± 1.8 vs. 5.3 ± 1.3, p = .045), and shorter procedure times (170 ± 57 vs. 228 ± 91 min, p = .082) compared to the seven cryoablation patients without such sites. Four patients had transient AV block by ablation inside the Lumipoint-highlighted area with fractionated signals, but no patient developed permanent AV block or recurrence post-procedure (median follow-up: 375 days). SP modification ablation at the collision site of atrial activation of the tricuspid-annulus side along with a spiky potential could provide a better outcome.

Efficacy and safety between radiofrequency ablation and types of cryoablation catheters for atrioventricular nodal reentrant tachycardia: A Network Meta-analysis and Systematic Review.

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common supraventricular tachycardia referred for ablation. Periprocedural conduction system damage was a primary concern during AVNRT ablation. This study aimed to assess the incidence of permanent atrioventricular (AV) block and the success rate associated with different types of catheters in slow pathway ablation. A literature search was performed to identify studies that compared various techniques, including types of radiofrequency ablation (irrigated and nonirrigated) and different sizes of catheter tip cryoablation (4, 6, and 8-mm), in terms of their outcomes related to permanent atrioventricular block and success rate. To assess and rank the treatments for the different outcomes, a random-effects model of network meta-analysis, along with p-scores, was employed. A total of 27 studies with 5110 patients were included in the analysis. Overall success rates ranged from 89.78% to 100%. Point estimation showed 4-mm cryoablation exhibited an odds ratio of 0.649 (95%CI: 0.202-2.087) when compared to nonirrigated RFA. Similarly, 6-mm cryoablation had an odds ratio of 0.944 (95%CI: 0.307-2.905), 8-mm cryoablation had an odds ratio of 0.848 (95%CI: 0.089-8.107), and irrigated RFA had an odds ratio of 0.424 (95%CI: 0.058-3.121) compared to nonirrigated RFA. Our study found no significant difference in the incidence of permanent AV block between the types of catheters. The success rates were consistently high across all groups. These findings emphasize the potential of both RF ablation (irrigated and nonirrigated catheter) and cryoablation as viable options for the treatment of AVNRT, with similar safety and efficacy profile.

Novel Aortic Valve Replacement Technique for Reducing Complete Heart Block.

Aortic valve replacement (AVR) may complicate conduction abnormalities and require permanent pacemaker (PPM) implantation. New techniques that lessen this challenge may lead to the development of new approaches. Our objective was to evaluate the contemporary incidence of early postoperative PPM implantation in patients undergoing isolated AVR and root disease with the standard AVR surgical technique compared with the novel suture AVR technique. The clinical data of 354 patients (250 male, 104 female) who underwent surgery for isolated AVR and root disease in different referral cardiology departments in Tabriz, Iran, over 4 years were analyzed. Patients with preoperative significant conduction abnormalities were excluded from the study. The patients were evaluated for in-hospital mortality, postoperative PPM implantation, and their stay in the ICU after surgery. The mean age of the patients was 52.46±16.13 years. Totally, 183 patients (51.7%) were operated on with the new suture AVR technique. In-hospital mortality was lower in this group than in the group that underwent the "classic" surgical technique (2.5% vs 3.7%). PPM implantation was required in 3 patients (0.8%) after the novel suture AVR technique, whereas it was needed in 12 patients (3.4%) in the other group (P=0.024). The mortality rate was 9 patients (2.5%) in group 1 and 13 patients (3.7%) in group 2, which was not statistically significant (P=0.296). According to the logistic regression, the survival rate in the group operated on with the classical surgical method was 0.27 times higher than that in the patients operated on with the new method. Permanent complete AV block is a critical complication after AVR surgery. A lower PPM requirement and higher survival in patients operated on with the new method was the main finding of this study. New techniques with lower PPM requirements may be suitable for cardiac surgery.

Long-Term Follow-Up of Empirical Slow Pathway Ablation in Pediatric and Adult Patients with Suspected AV Nodal Reentrant Tachycardia.

The aim of this study was to assess long-term efficacy and safety of empirical slow pathway (ESP) ablation in pediatric and adult patients with a special interest in patients without dual AV nodal physiology (DAVNP). A retrospective single-center review of patients who underwent ESP ablation between December 2014 and September 2022 was performed. Follow-up included telephone communication, letter questionnaire and outpatient presentation. Recurrence was based on typical symptoms. 115 patients aged 6-81 years (median age 36.3 years, 59.1% female; 26 pts < 18 years) were included. A typical history was present in all patients (100%), an ECG documentation of narrow complex tachycardia in 97 patients (84%). Patients were divided into three groups: Group 1 without DAVNP (n = 23), Group 2 with AH jump (n = 30) and Group 3 with AH jump and at least one AV nodal echo beat (n = 62). No permanent AV block was observed. During a median follow-up of 23.6 ± 22.7 months, symptom recurrence occurred in 7/115 patients (6.1%) with no significant difference between the groups (p = 0.73, log-rank test). Symptom recurrence occurred significantly more often in patients without (5/18 patients; 27%) as compared to patients with ECG documentation (2/97 patients; 2.1%; p = 0.025). No correlation between age and success rate was found (p > 0.1). ESP ablation is effective and safe in patients with non-inducible AVNRT. Overall, recurrence of symptoms during long-term follow-up is low, even if no DAVNP is present. Tachycardia documentation before the EP study leads to a significantly lower recurrence rate following ESP ablation.

Incidence, Risk Factors, and Outcomes of Conduction Disturbances After Percutaneous Closure of Perimembranous Ventricular Septal Defects in Children and Adolescents: A Mid-term Follow-up

Background: Conduction disturbance (CD) is a major complication of percutaneous closure of the perimembranous ventricular septal defect (pmVSD). Objectives: This study aimed to investigate the incidence, predisposing factors, and outcomes of sustained CD following percutaneous closure of these defects. Methods: All patients whose pmVSD was closed successfully with percutaneous methods within April 2016 to April 2021 were enrolled in this cohort study. The defects’ size, septal aneurysms, and distance to the aortic valve annulus were determined with transthoracic echocardiography and catheterization. Continuous heart monitoring was performed during the procedures and one hour after, and standard 12-lead electrocardiograms were obtained regularly to determine any CD and arrhythmias. Results: A total of 260 patients who had successful pmVSD closure were enrolled in the study. In this study, 135 (52%) and 125 (48%) patients were male and female, respectively. The mean age of the patients was 75.66 ± 68.89 months. The patients’ median follow-up was 36 months (range: 9-210 months). Thirty-one patients (11.9%) developed sustained CD, and 25 cases recovered to normal conduction. Additionally, 7 patients (2.7%) had several permanent conduction abnormalities, including four right bundle branch blocks, two left bundle branch blocks, and one bi-fascicular block. No one had a permanent atrioventricular block. Closure of non-aneurysmal defects and more prolonged procedures were independent risk factors of CD. Using Amplatzer duct occluder type II was associated with less incidence of conduction abnormalities. Conclusions: The incidence of sustained CD after transcatheter closure was relatively high; however, most cases recovered to normal conduction. The use of softer devices and the placement of devices into the septal aneurysms might lower the risk of CD.

First long-term outcome data for the MicraVR™ transcatheter pacing system: data from the largest prospective German cohort

AimsThe MicraVR™ transcatheter pacing system (TPS) has been implemented into clinical routine for several years. The primary recipients are patients in need for VVI pacing due to bradycardia in the setting of atrial fibrillation (AF). Implantation safety and acute success have been proven in controlled studies and registries.So far only few long-term real-life data on TPS exist. We report indication, procedure and outcome data from two high-volume implanting German centers.MethodsBetween 2016 and 2019, 188 (of 303) patients were included. During follow-up (FU), TPS interrogation was performed after 4 weeks and thereafter every 6 months.ResultsIndication for TPS implantation in 159/188 (85%) patients was permanent or intermittent AV block III° in the setting of atrial fibrillation.The mean procedure duration was 50 min [35.0–70.0]. The average acute values after system release were: thresholds: 0.5V [0.38–0.74]/0.24ms; R-wave sensing: 10.0mV [8.1–13.5]; impedance: 650 Ohm [550–783]; RV-pacing demand: 16.9% [0.9–75.9]; and battery status: 3.15 V [3.12–3.16]. During FU of 723.4 ± 597.9 days, neither pacemaker failure nor infections were reported.Long-term FU revealed: thresholds: 0.5V [0.38–0.63]/0.24 ms; sensing: 12.3mV [8.9–17.2]; impedance: 570 Ohm [488–633]; RV-pacing demand: 87.1% [29.5–98.6]; and battery status 3.02 V [3.0–3.1]. Forty-three patients died from not-device-related causes.ConclusionThis to date largest German long-term dataset for MicraVR™ TPS implantation revealed stable device parameter. Foremost, battery longevity seems to fulfill predicted values despite a significant increase in RV-pacing demand over time and even in patients with consecutive AV-node ablation. Of note, no infections or system failure were observed.Graphical abstract

Usefulness of parahisian pacing for risk prediction of pacemaker implantation after TAVI

Abstract Funding Acknowledgements Type of funding sources: None. Background Conduction disturbances determining pacemaker implantation are a significant concern in patients undergoing Transcatheter Aortic Valve Implantation (TAVI), a procedure that is nowadays spreading even in the low-risk population. OBJECTIVE The aim of the study was to evaluate the role of the parahisian pacing, a method to directly identify the conduction system anatomical variability, in predicting the iatrogenic damage risk conditioning pacemaker implantation after TAVI. Methods Between October 2021 and November 2022 we prospectively collected clinical features, ECG, procedural and imaging data (cardiac CT and echocardiography) of every patient who underwent electrophysiological study for pre-existing or worsening conduction disorders within 48 hours after TAVI procedures in our centre. After having recorded the HV interval, parahisian stimulation at decreasing energy output was performed (CL 600 ms, 25V to 0.5V x 2 ms) with definition of the loss of capture pattern related to the three anatomical variations of His bundle described by Kawashima (1). Fisher’s exact test was used for statistical analysis; p-value &amp;lt;0.05 was considered statistically significant. Results Out of 110 TAVI performed, a total of 31 patients with conduction disorders have been studied. Patients who developed permanent 3rd degree AV block after the procedure were excluded. Mean age was 82.6±4.4 years; 21 patients (67.7%) were males. 11 patients (35.5%) had a pre-existing conduction disorder worsened after TAVI, 13 patients (41.9%) developed newly-onset LBBB; 8 (25.8%) also developed 1st degree AV block. The total number of patients who underwent PM implantation was 16 (51.6%). The anatomical variables (membranous septum &amp;lt;3mm and/or septal cusps calcifications) and type of valve implanted were not significantly associated with PM implantation (p = NS). An HV interval &amp;lt;70 ms was registered in 20 (64.5%) patients (Fig. 1); 7 of them underwent PM implantation as they developed paroxysmal 3rd degree AV block. These 7 patients all had type 2 or type 3 pattern during parahisian stimulation. None of the patients undergoing PM implantation presented a type 1 pattern during parahisian stimulation. A significant protective value (p = 0.02) for PM implantation in patients with type 1 pattern was observed (Fig. 2). Conclusions Parahisian stimulation can be a useful tool to define the conduction system anatomical variability. It can also be helpful to predict the conduction system damage risk during TAVI, conditioning PM implantation. Our data need to be confirmed in a larger population.

Comparison of Surgical Techniques Used in Ventricular Septal Defect Closure.

We compared transatrial closure, tricuspid valve septal detachment, and tricuspid valve chordal detachment techniques for ventricular septal defect (VSD) closure. Patients who had VSD closure with three different techniques in our clinic between September 2016 and December 2020 were retrospectively reviewed. A total of 117 patients were included in the study. The patients were divided into three groups: group 1, classical transatrial closure; group 2, closure with tricuspid valve septal detachment; and group 3, closure with tricuspid valve chordal detachment. The groups were evaluated by serial transthoracic echocardiography (preoperative, postoperative 1st day, postoperative 1st month). Cardiac rhythm checks and recordings were performed. No residual VSD was observed in early or late periods in any of the groups whose VSD closure was performed with the three different techniques. No severe tricuspid regurgitation (TR) was detected during the early and late postoperative periods of all operating procedures. When the groups were compared in terms of early/late TR after the operation (without TR+trace amount of TR and mild TR+moderate TR were compared), no statistically significant difference was found (P>0,05; P=0,969 and P>0,05; P=0,502). In this study, we found no statistically significant difference between three VSD closure techniques in terms of early TR, late TR, residual VSD, and permanent atrioventricular complete block during postoperative period. We hope that our results will be supported by the results of researches that are being made about this subject in large series.

Correlation between AV synchrony and device collected AM-VP sequence counter in atrioventricular synchronous leadless pacemakers: A real-world assessment.

Micra atrioventricular(AV) provides leadless atrioventricular synchronous pacing by sensing atrial contraction (A4 signal). Real-world operation and reliability of AV synchrony (AVS) assessment using device data have not been described. The purposes of this study were to (1) assess the correlation between AVS and atrial mechanical sensed-ventricular pacing(AM-VP) percentages in patients with permanent high-degree AV block and (2) report on the real-world effectiveness of Micra AV. The correlation between ECG-determined AVS in-clinic and device-collected %AM-VP was assessed using data from 40 patients with high-degree AV block enrolled in the Micra Atrial tRacking using a Ventricular AccELerometer(MARVEL) 2 study. A retrospective analysis to assess continuously-sampled %AM-VP since last session, device programming, and electrical parameters was performed using Micra AV transmissions from the Medtronic CareLink database. Patients with transmissions ≥180 days postimplant were included. Among the 40 MARVEL 2 AV block patients with a median %VP of 99.7%, AVS was highly correlated with AM-VP (median AVS 87.1%, median AM-VP 79.1%; R2 = 0.764, p < .001). The CareLink cohort included 4384 patients programmed to VDD mode. The mean A4 amplitude was 2.3 ± 1.8 m/s2 at implant and 2.3 ± 1.6 m/s2 at 28 weeks. In patients with %VP>90% (n = 1662), the median %AM-VP was 74.7%. For the full cohort, median %VP was 65.6% and median projected battery longevity was 10.5 years. In patients with a high pacing burden, %AM-VP provides a reasonable estimation of AVS. The first large real-world analysis of Micra AV patients with >90% VP showed stable atrial sensing over time with a median %AM-VP, a correlate of AVS, of 74.7%.

Outcomes of catheter ablation for typical atrioventricular nodal reentrant tachycardia with low power energy

Abstract Background Atrioventricular nodal reentrant tachycardia (AVNRT) is most common supraventricular tachycardia with acceptable outcome of catheter ablation. However, the serious complication of atrioventricular block (AVB) can occur and affects 0.2% to 2.3% of patients during or after procedures. Purpose We hypothesized that slow pathway ablation with 20 watt (W) energy would facilitate acceptable clinical outcomes and low procedure related AVB needed permanent pacemaker. Methods Prospective single center trial was performed. Slow pathway ablation was performed in 212 patients (mean age 56.5±18.4 years, 131 women) from January 2017 to May 2020. Twenty watt energy was delivered at the posterior region of the triangle of Koch until accelerated junctional rhythm was obtained. Results A total of 212 patients who underwent ablation for typical AVNRT were included. The acute success rate, the mean radiofrequency pulses applied per patient were 98.1% and 8.6±6.6, respectively. Transient AVB occurred in 5 patients (2.4%) and no permanent AVB requiring permanent pacemaker implantation occurred. Those who failed 20 W ablation were younger (success group age vs failed group age 58.2±17.4 vs 31.8±17.9 years, p=0.005) and had a faster heart rate just before slow pathway ablation (success group heart rate vs failed group heart rate 69.2±11.3 vs 76.8±5.6 bpm, p=0.59). The recurrence rate of 20 W ablation was 2.6% and the follow-up period was 18.3±4.1 months. Conclusion The low power approach for slow pathway ablation is highly effective and safe. If the heart rate just before ablation is lesser than 70 bpm, slow pathway ablation with 20 W energy could be considered. Further well-designed large-randomized studies are needed to define the role and effect of catheter ablation for typical AVNRT with low power energy. Funding Acknowledgement Type of funding sources: None.

Zero-fluoro AVNRT ablation

Abstract Background Atrioventricular-nodal reentry tachycardia (AVNRT) is a common supraventricular tachycardia, particularly in younger patients. First-line therapy in symptomatic patients is radiofrequency catheter ablation (RFCA). Catheter placement and ablation are typically performed by fluoroscopy guidance implying a non-negligible exposure of ionizing radiation for patient and laboratory personnel. Purpose We aimed to demonstrate feasibility and safety of AVNRT ablation using 3D-electroanatomic mapping (3D-EAM) as sole and additional means of catheter guidance compared to conventional fluoroscopic positioning. Endpoints were: procedure duration, fluoroscopy duration, radiation dose and occurrence of any complication. Methods We retrospectively included consecutive patients (n=68, mean age 55±18 years) who underwent RFCA of AVNRT between 01/2020 and 12/2021 in our hospital. One group was a priori allocated to conventional fluoroscopy mapping (convFluoro, n=30), the other procedures were performed under 3D-EAM using Ensite NavX (NavX). From the latter, slow-pathway RFCA could be performed without any fluoroscopy (zeroFluoro) in 20 patients, in 18 cases additionally fluoroscopy was used due to difficult anatomic conditions (NavX+Fluoro). Success of RFCA was defined as slow-pathway elimination. Results There was no significant difference in procedure duration between the convFluoro and overall NavX group (74±24 min vs. 87±29 min, P=NS). However, NavX+Fluoro group (comprising more complicated cases) had longer procedure duration compared to convFluoro group (94±30 min vs. 74±24 min, p&amp;lt;0.05). The use of 3D-EAM significantly reduced fluoroscopy duration comparing convFluoro with NavX+Fluoro (12±9 min vs. 7±6 min, p&amp;lt;0.05) and convFluoro with overall NavX-group (12±9 min vs. 3±5 min, p&amp;lt;0.0001). Likewise, radiation dose was significantly decreased by means of 3D-EAM (NavX: 60±113 cG cm2 vs. convFluoro: 169±166 cG cm2, p&amp;lt;0.01). 3D-EAM guided RFCA was successful in all patients (100%), success rate in convFluoro-group was 87% (P=NS). Minor complications occurred in two cases (7%) in the convFluoro-group and 4 cases (11%) in the NavX-group (P=NS). No severe complication, such as pericardial effusion or permanent AV-block occurred in any group. Conclusion Zero-fluoroscopy 3D-EAM-guided RFCA in patients with AVNRT is feasible and safe. Without prolonging procedure duration, 3D-EAM can reduce fluoroscopy duration leading to lower radiation exposure and making electrophysiological study safer for laboratory staff and patients. Funding Acknowledgement Type of funding sources: None.