Left bundle branch area pacing in patients with baseline narrow, left, or right bundle branch block QRS patterns: insights into electrocardiographic and echocardiographic features.

AIMS: Left bundle branch area pacing (LBBAP) is a recent technique aiming at preservation of physiological ventricular electrical activation. Our goal was to assess mechanical synchrony parameters in relation to electrocardiographic features during LBBAP performed in routine practice. METHODS AND RESULTS: From June 2020 to August 2021, all patients of our institution with permanent pacemaker implantation indication were eligible for LBBAP. A 'qR' pattern in V1 and a delay from pacing spike to the peak of the R-wave in V6 < 80 ms defined a successful LBBAP. Electrocardiogram and echocardiography were performed during spontaneous rhythm and LBBAP: left ventricular mechanical synchrony (LVMS) parameters using 2D Speckle tracking and interventricular mechanical delay (IVMD) were collected. LBBAP was attempted with success in 134/163 patients (82.2%). During LBBAP, the mean QRS width was 104 ± 12 ms. In patients with left bundle branch block (n = 47), LBBAP provided a significant decrease of QRS width from 139 ± 16 to 105 ± 12 ms (P < 0.001) with reduction of LVMS (53 ± 21 vs. 90 ± 46 ms, P = 0.009), and IVMD (14 ± 13 vs. 49 ± 18 ms, P < 0.001). In patients with right bundle branch block (n = 38), LBBAP led to a significant decrease of QRS width from 134 ± 14 to 106 ± 13 ms (P < 0.001) with no effect on LVMS and a reduction of IVMD (17 ± 14 vs. 50 ± 16 ms, P < 0.001). CONCLUSION: LBBAP in routine practice preserved intra-ventricular mechanical synchrony in patients with narrow and RBBB QRS and improved asynchrony parameters in patients with LBBB.

Can permanent His bundle pacing be safely started by operators new to this technique? Data from a multicenter registry.

BACKGROUND: Right ventricular pacing (RVP) induces ventricular asynchrony in patients with normal QRS and increases the risk of heart failure and atrial fibrillation in long term. His bundle pacing (HBP) is a physiological alternative to RVP, and could overcome its drawbacks. Recent studies assessed the feasibility and safety of HBP in expert centers with a vast experience of this technique. These results may not apply to less experienced centers. We aim to evaluate the feasibility and safety of permanent HBP performed by physicians who are new to this technique. METHODS: We included all patients who underwent pacemaker implantation with attempt of HBP in three hospitals between September 2017 and January 2020. Indication for HBP was left to operators' discretion. All the operators were new for HBP. His bundle (HB) electrical parameters were recorded at implant, 3- and 12-month follow-up. RESULTS: HBP was successful in 141 of 170 patients (82.9%); selective HBP was obtained in 96 patients and nonselective HBP in 45. The mean procedure and fluoroscopy durations were 67.0 ± 28.8 min, and 7.3 ± 8.1 min (3.1 ± 4.1 Gy·cm2 ), respectively. The mean HB paced QRS duration was 106 ± 18 ms. The mean HB capture threshold was 1.29 ± 0.77 V and did not increase at 3- and 12-month follow-up. The ventricular lead revision was required in five patients. Our results showed a rapid technical learning allowing a high procedure success rate (89.8%) after 15 procedures. CONCLUSION: HBP performed by operators new to this technique appeared feasible and safe. This should encourage HBP to be performed in patients expected to experience high RVP burden.

New safe approach to target symptomatic Hisian ectopy/tachycardia.

AIMS: Although cryoenergy safety profile is appropriate for the ablation of arrhythmogenic foci near the conduction system, mapping using the cryoablation catheter is of limited precision. Combining the safety of cryoenergy and the high precision of a 3D mapping system therefore appears the most appropriate set-up for ablation in the vicinity of the His bundle. METHODS AND RESULTS: A 29-year-old woman with a 3-year history of increasing shortness of breath and palpitations refractory to medical treatment was sent to the electrophysiology (EP) laboratory for catheter ablation. Surface electrocardiogram showed sinus rhythm and frequent ectopic beats with narrow QRS complexes similar to those of the sinus beats. The left ventricular ejection fraction was impaired (38%) with no other aetiology found, apart from frequent ectopies. Detailed intracardiac mapping, using a 3D electroanatomical system, revealed that the ectopy originated from the distal His bundle, which was indicated by both antegrade and reversed His bundle activation sequence during ectopy compared to that during sinus rhythm. Due to the proximity of the conduction system, cryoenergy rather than radiofrequency was chosen to target this Hisian ectopy. A special set-up was made in order to allow the cryoablation catheter to be visualized into the 3D mapping system. Cryoenergy delivered to the site of earliest Hisian ectopy activation completely abolished it. CONCLUSION: Such a combined approach may help to improve the therapeutic strategy for ablation procedures with a high risk of injury to the conduction system. It could notably be extended to the ablation of para-Hisian ectopy or accessory pathways.

Very long-term outcomes after catheter ablation of atrioventricular nodal reentrant tachycardia: How does cryoenergy differ from radiofrequency?

INTRODUCTION: Either cryoenergy or radiofrequency can be used during atrioventricular nodal reentrant tachycardia (AVNRT) ablation. There are still limited data comparing their respective long-term efficacy (>1 year). This study sought to compare the very long-term outcomes of AVNRT ablation using radiofrequency or cryotherapy. METHODS: We retrospectively included all patients who had undergone a first AVNRT ablation in our institution between January 2010 and December 2017. The primary endpoint was recurrence of documented AVNRT. RESULTS: The study population consisted of 409 patients (274 females; mean age, 49.9 years). Ablation was performed using cryoenergy in 260 patients and radiofrequency in 149. High acute procedural success rate (>98%) was obtained and no permanent AV block was observed using both techniques. During a mean follow-up of 3.3 ± 2.3 years, documented AVNRT recurrence occurred in 24 (9.2%) and 4 patients (2.7%) in the cryoablation (CA) and radiofrequency (RF) group, respectively. The risk of AVNRT recurrence was significantly higher in the CA group as compared with the RF group (hazard ratio [HR] = 3.7; 95% confidence interval [CI], 1.3-5.9). Most of the recurrences after CA occurred between 1- and 6-year follow-up (14/24; 58.3%), with one-third of late recurrences after 3-year follow-up. In multivariable analysis, only Koch's triangle anatomical variant was associated with AVNRT recurrence after CA (HR = 6.7; 95% CI, 2.7-16.3). CONCLUSION: While AVNRT recurrence rates were similar at 1 year of follow-up regardless of the energy used, long-term efficacy appeared higher after radiofrequency ablation. Strikingly, recurrences occured much later after cryotherapy compared with radiofrequency ablation.

Pacemaker memory in post-TAVI patients: Who should benefit from permanent pacemaker implantation?

BACKGROUND: One of the most frequent complications of transcatheter aortic valve implantation (TAVI) is the occurrence of atrioventricular (AV) conduction disorders secondary to AV node or His bundle injury leading to permanent pacemaker implantation (PPI). The objective was to quantify the rate of ventricular pacing (VP), according to post-TAVI indication for PPI using recorded pacemaker memory. METHODS: From October 2009 to January 2017' all patients who had PPI following TAVI performed at Rouen University Hospital were included. Indications for PPI were: ≥ 1 episode of complete atrioventricular block (CAVB) or 2:1 atrioventricular block, and new-onset persistent left bundle branch block (NOP-LBBB) with either prolonged PR interval (> 200 ms) or HV interval (>70 ms). The primary endpoint was VP percentage at the first pacemaker interrogation (a VP percentage ≥ 1% was considered as significant). RESULTS: Out of 936 TAVI patients (Sapien-3' n = 379 [Edwards Lifesciences, Irvine, CA, USA]; Sapien-XT' n = 513; CoreValve' n = 44, Medtronic, Minneapolis, MN, USA), 87 (9.3%) had PPI. Eighty of these 87 patients were followed-up and analyzed. At the first pacemaker interrogation, a significant VP percentage was observed in 60/80 followed-up patients (75%), in 46/51 patients (90.2%) implanted for CAVB, and 12/23 patients (52.2%) implanted for NOP-LBBB associated with either prolonged PR or HV interval. No clinical predictive factor of significant VP percentage was found. CONCLUSION: In the post-TAVI period, our data support PPI in patients with CAVB even if paroxysmal. Our data also suggest PPI may be considered in patients with NOP-LBBB associated with either prolonged PR or HV interval.

Lessons from radiofrequency redo-procedure after cryoballoon pulmonary vein isolation for paroxysmal atrial fibrillation.

BACKGROUND: To gain further insights into mechanisms leading to atrial fibrillation (AF) recurrence after a first ablation procedure using cryoballoon technique, the data collected during redo procedure were analyzed. METHODS AND RESULTS: From a total of 112 patients who underwent cryoballoon pulmonary vein isolation (PVI) for paroxysmal AF, 44 had a second ablation procedure using radiofrequency catheter, because of recurrent atrial arrhythmia. PV reconduction was observed in 109 of the 171 initially isolated veins (64%). Conduction recovery was found, respectively, at the left inferior PV, right inferior PV, right superior PV and left superior PV in 35 patients (80%), 26 patients (67%), 23 patients (52%) and 17 patients (39%). The mean number of reconnected PVs per patient was significantly lower with the 23-mm cryoballoon as compared to the 28-mm. Conduction gaps were focal and located at inferior parts of inferior veins and at the ridge between left atrial appendage and left veins. Mean procedure and fluoroscopy time were 109 ± 32 min and 14.7 ± 8.3 min, respectively. A 3-D mapping system was used in only 8 patients (18%). CONCLUSIONS: Atrial arrhythmia recurrences following cryoballoon PVI were associated with focal PV reconnections, occurring at preferential anatomical sites. These gaps were readily ablated with focal radiofrequency delivery, explaining the lack of need of 3-D mapping system and short procedure time. These results do not support the use of cryoballoon to perform redo procedures.

Is excessive ventricular irregularity predictive of rehospitalization in patients with permanent AF and HFpEF?

AIMS: There are currently limited therapeutic approaches for patients with heart failure with preserved ejection fraction (HFpEF) who have developed permanent atrial fibrillation (AF). We aimed to analyse the impact of ventricular irregularity on heart failure rehospitalization in patients with permanent AF and HFpEF. METHODS AND RESULTS: All 24 h ambulatory Holter monitoring performed in our centre within a month after a first heart failure hospitalization were screened. Patients with HFpEF and permanent AF were included in the retrospective analysis. The following parameters of ventricular irregularity were calculated over the 24 h recording period: standard deviation of all RR intervals (SDNN), coefficient of variation of SDNN (CV-SDNN = SDNN/mean RR), root of the mean squared differences of successive RR intervals (RMSSD), and percentage of consecutive RR intervals with difference over 50 ms (pNN50). The primary endpoint was rehospitalization for acute heart failure (HFrH). From 2010 to 2021, 51/216 screened patients were included. During a median follow-up of 3.13 years, 29/51 patients reached the primary endpoint. HFrH patients had higher SDNN (205 ± 65 vs. 154 ± 46 ms; P < 0.01), CV-SDNN (26 ± 8% vs. 19 ± 5%, P < 0.01), RMSSD (182 ± 47 vs. 138 ± 65 ms, P = 0.013), and pNN50 (76 ± 9 vs. 58 ± 26, P < 0.001) when compared with patients with no HFrH. In multivariate analysis, all those parameters remained significantly associated with HFrH. CONCLUSIONS: In this pilot study, we found some evidences for a deleterious impact of excessive ventricular irregularity on HFrH in AF patients with HFpEF. Those new findings could pave the way for new prognosis and therapeutic approaches in this patients' population.

RVOT premature ventricular contractions induce significant anatomical displacement during 3D mapping: A cause of mid-term ablation failure?

BACKGROUND: Catheter ablation is a first-line treatment for symptomatic right ventricular outflow tract (RVOT) premature ventricular complexes (PVCs). There is evidence of displacement of the ablation target site during PVCs relative to the location in sinus rhythm (SR). AIM: To analyse the extent of displacement induced by RVOT PVCs and its effect on the ablation sites and the mid-term efficacy of ablation. METHODS: In this multicentre French study, we retrospectively included 18 consecutive adults referred for ablation of RVOT PVCs using a three-dimensional (3D) mapping system. PVC activation maps were performed conventionally (initial map), then each PVC activation point was manually reannotated considering the 3D location on a previous SR beat (corrected map). The ablation-site locations on the initial or the corrected area, including the 10 best activation points, were analysed. Mid-term efficacy was evaluated. RESULTS: The direction of map shift during PVCs relative to the map in SR occurred along a vertical axis in 16 of 18 patients. The mean activation-point displacement for each of the 18 mapped chambers was 5.6±2.2mm. Mid-term recurrence of RVOT PVCs occurred in 5 (28%) patients. In all patients with recurrences, no significant ablation lesion was located on the corrected (true) site of origin. CONCLUSIONS: RVOT PVCs induce a vertical anatomical shift that can mislead physicians about the true location of the arrhythmia's site of origin. Our study highlights the association between mid-term PVC recurrence and the absence of spatial overlap between ablation points and the corrected site of origin.

His-bundle pacing and atrioventricular nodal ablation for noncontrolled atrial arrhythmia: A technical challenge with major clinical benefits.

BACKGROUND: His-bundle pacing (HBP) is an appealing alternative to right ventricular pacing in patients referred for permanent ventricular pacing and atrioventricular nodal ablation (AVNA) because it preserves physiological ventricular activation. Only limited data regarding HBP combined with AVNA are available in the literature. OBJECTIVE: The purpose of this study was to provide further evidence on the feasibility and efficacy of this therapeutic approach in patients with uncontrolled atrial arrhythmia. METHODS: We prospectively included all patients who had undergone AVNA after HBP in 3 different hospitals between 2017 and 2022. RESULTS: AVNA following HBP lead implantation was performed in 75 patients. Complete atrioventricular (AV) block was obtained in 58 patients (77%), and significant modulation of AV nodal conduction (heart rate <60 bpm) was obtained in 12 patients (16%). AVNA failure was observed in 5 patients (7%). Recording of an atrial signal by the HBP lead was more frequently observed in patients with AVNA modulation/failure than in patients with complete AV block (11/17 vs 5/58; P <.001). No lead dislodgment occurred during the AVNA procedures. Acute His-bundle (HB) capture threshold increase >1 V occurred in 11 patients (15%), with return to baseline value on day 1 in 9 patients. New York Heart Association functional class and left ventricular ejection fraction significantly improved from baseline to last follow-up (3.0 ± 0.7 vs 1.6 ± 0.5; P <.001; and 47% ± 14% vs 60% ± 9%; P <.0001, respectively). CONCLUSION: AVNA combined with HBP for noncontrolled atrial arrhythmia was feasible and clinically efficient. Implanting the HB lead on the ventricular aspect of the tricuspid annulus avoiding atrial signal recording can facilitate AVNA.

Collateral nervous damages after cryoballoon pulmonary vein isolation.

INTRODUCTION: Various types of complications have been reported after atrial fibrillation (AF) ablation using radiofrequency energy, but those have not been well defined when using cryoballoon ablation technique. The objective of this prospective study was to assess types, incidence, and outcome of complications after cryoballoon pulmonary vein isolation (PVI). METHODS AND RESULTS: This prospective monocentric study included 66 consecutive patients (39 males, age 57 ± 11 years) who underwent cryoballoon PVI for symptomatic paroxysmal AF. Phrenic nerve (PN) integrity was assessed by pacing from the superior vena cava during isolation of the right PVs. Before discharge, all patients were subjected to 24-hour Holter electrocardiograms, echocardiography, and esophagogastroduodenoscopy. Cardiac MRI was scheduled between 1 and 3 months postprocedure. At 3.7 ± 1.7 months after ablation, patients underwent clinical review and 24-hour Holter electrocardiograms. The mean number of cryoballoon applications was 10.0 ± 2.1 per patient and 2.5 ± 1.0 per vein. A 28 mm cryoballoon was used in 49 patients (74%) and a 23 mm cryoballoon in the remaining 17 patients (26%). Twelve complications (18%) attributing to collateral nervous damage were noticed in 9 patients: asymptomatic gastroparesis was observed in 6 patients (9%), transient PN palsy (PNP) in 5 (8%), and symptomatic inappropriate sinus tachycardia requiring beta-blocker treatment in 1 (1%). Neither cryoballoon-related esophageal ulceration nor PV stenosis was observed. CONCLUSION: Gastroparesis and PNP could be observed in a significant number of cases after cryoballoon ablation of AF. These complications are likely due to cryo-induced damages to nervous structures surrounding the heart.

Isolation of the phrenic nerve to suppress diaphragmatic contraction induced by cardiac resynchronization.

Left phrenic nerve stimulation is a well-known complication of cardiac resynchronization therapy (CRT). We report a case where electronic or anatomical repositioning of the left ventricular (LV) electrode (within the coronary sinus tributaries) was not feasible/effective. Surgical graft interpositioning was performed to successfully isolate the phrenic nerve from the previously implanted coronary sinus epicardial LV lead.

Significant mitral regurgitation regression by slight modification of the right ventricular pacing site.

A dual-chamber pacemaker was implanted because of symptomatic bradycardia in a 60-year-old patient free from other heart disease. Then, the patient developed acute congestive heart failure due to pacing-induced mitral regurgitation (MR). Under echocardiographic guidance, modification of location of the right ventricular pacing lead led to a significant decrease in MR severity resulting in immediate clinical improvement.

Complete pacemaker lead fracture potentially due to intra-cardiac mass.

Seven years after the implantation of a dual-chamber pacemaker, a 74-year-old woman was referred for syncope. Chest X-ray revealed that the ventricular lead was completely broken near the tricuspid valve. Fluoroscopy and transthoracic echocardiography found a calcified mass, moving with the proximal part of the ventricular lead. Anatomopathology of the atrial tumour remained unknown. Surgery was considered too invasive a technique to be performed in our patient, who was suffering from dementia.

Autonomic regulation of the heart and arrhythmogenesis in trained breath-hold divers.

AbstractBreath-hold divers are known to develop cardiac autonomic changes and brady-arrthymias during prolonged breath-holding (BH). The effects of BH-induced hypoxemia were investigated upon both cardiac autonomic status and arrhythmogenesis by comparing breath-hold divers (BHDs) to non-divers (NDs). Eighteen participants (9 BHDs, 9 NDs) performed a maximal voluntary BH with face immersion. BHDs were asked to perform an additional BH at water surface to increase the degree of hypoxemia. Beat-to-beat changes in heart rate (HR), short-term fractal scaling exponent (DFAα1), the number of arrhythmic events [premature ventricular contractions (PVCs), premature atrial contractions (PACs)] and peripheral oxygen saturation (SpO2) were recorded during and immediately following BH. The corrected QT-intervals (QTc) were analyzed pre- and post-acute BH. A regression-based model was used to split BH into a normoxic (NX) and a hypoxemic phase (HX). During the HX phase of BH, BHDs showed a progressive decrease in DFAα1 during BH with face immersion (p < 0.01) and BH with whole-body immersion (p < 0.01) whereas NDs did not (p > 0.05). In addition, BHDs had more arrhythmic events during the HX of BH with whole-body immersion when compared to the corresponding NX phase (5.9 ± 6.7 vs 0.4 ± 1.3; p < 0.05; respectively). The number of PVCs was negatively correlated with SpO2 during BH with whole-body immersion (r = -0.72; p < 0.05). The hypoxemic stage of voluntary BH is concomitant with significant cardiac autonomic changes toward a synergistic sympathetic and parasympathetic stimulation. Co-activation led ultimately to increased bradycardic response and cardiac electrophysiological disturbances.

Are routine cryoballoon procedural characteristics predictive of atrial arrhythmia recurrence in the long term?

BACKGROUND: Cryoballoon ablation is an effective procedure to treat atrial fibrillation (AF). However, AF recurrence rate at 1-year follow-up is approximately 20% despite improvements in ablation technique. AIM: To find factors predictive of AF recurrence following a first pulmonary vein isolation procedure using a second-generation cryoballoon (PVI-2CB). METHODS: This was an observational, retrospective, single-centre study. From June 2012 to April 2017, all patients who had a PVI-2CB procedure and a scheduled follow-up at Rouen University Hospital were included. The primary endpoint was atrial arrhythmia (AA) recurrence (e.g. AF, flutter or tachycardia), considering a blanking period of 2 months following the procedure. Secondary endpoints were procedural variables for each pulmonary vein (successful isolation, time to disconnection, total cryoballoon application time, number of cryoballoon applications, level of occlusion during cryoballoon application leading to successful disconnection and lowest temperature reached during successful cryoballoon application), occurrence of redo procedures, use of antiarrhythmic drugs and adverse events. RESULTS: The initial population consisted of 239 patients; six were excluded for lack of procedural variable data, giving an analysed population of 233 patients. The AA recurrence rate was 36.9% (mean follow-up 25±14 months). Mean time to AA recurrence was 10±12 months. No procedural variable was found to be predictive of AA recurrence. Only major left atrial enlargement (defined as diameter>50mm or left atrial area>30cm2 or left atrial volume>50mL/m2) was predictive (odds ratio 2.70, 95% confidence interval 1.54-4.72; P=0.001). Forty-one patients had redo procedures (17.6% of analysed population); in this subgroup, 75.6% had at least one pulmonary vein reconnected, mainly the right inferior pulmonary vein. CONCLUSIONS: At long-term follow-up, up to one-third of patients had AA recurrence after PVI-2CB. Important atrial remodelling was the only factor predictive of AA recurrence, whereas no procedural variable was found to be predictive.

Epicardial fat thickness predicts atrial fibrillation recurrence after a first pulmonary vein isolation procedure using a second-generation cryoballoon.

BACKGROUND: Atrial fibrillation is the most common arrhythmia in adults. A relationship between epicardial adipose tissue and atrial fibrillation has recently been reported. AIM: To evaluate the impact of epicardial fat thickness on the outcome of patients who underwent a first pulmonary vein isolation procedure using a second-generation cryoballoon. METHODS: From February 2012 to February 2017, all patients who underwent a first pulmonary vein isolation procedure using a second-generation cryoballoon at Rouen University Hospital were included. Data were collected retrospectively. Epicardial fat thickness was assessed by cardiac magnetic resonance imaging. The primary endpoint was documented atrial fibrillation recurrence at 4 months. RESULTS: A first pulmonary vein isolation procedure using a second-generation cryoballoon was performed in 288 patients; among them, 231 patients (80.2%) underwent cardiac magnetic resonance imaging. Epicardial fat thickness could be measured accurately in 206 patients (71.5%). Recurrence of atrial fibrillation at 4 months occurred in 32/206 patients (15.5%). In the multivariable analysis, factors predictive of atrial fibrillation recurrence at 4 months were: epicardial fat thickness (hazard ratio 1.96, 95% confidence interval 1.20-3.18; P=0.007), the presence of high left atrium enlargement (hazard ratio 4.63, 95% confidence interval 1.17-18.38; P=0.03) and atrial fibrillation recurrence before hospital discharge (hazard ratio 7.55, 95% confidence interval 2.50-22.81; P<0.001). CONCLUSION: Epicardial fat thickness is a predictive factor for atrial fibrillation recurrence after a first pulmonary vein isolation procedure using a second-generation cryoballoon.

Implantable cardioverter-defibrillators in lamin A/C mutation carriers with cardiac conduction disorders.

BACKGROUND: Sudden cardiac death is frequent in patients with lamin A/C gene (LMNA) mutations and may be related to ventricular arrhythmias (VA). OBJECTIVE: To evaluate a strategy of prophylactic implantable cardioverter-defibrillator (ICD) implantation in LMNA mutation carriers with significant cardiac conduction disorders. METHODS: Forty-seven consecutive patients (mean age 38 ± 11 years; 26 men) were prospectively enrolled between March 1999 and April 2009. Prophylactic ICD implantation was performed in patients with significant cardiac conduction disorders: patients requiring permanent pacing for bradycardia or already implanted with a pacemaker at the initial presentation, or patients with a PR interval of >0.24 seconds and either complete left bundle branch block or nonsustained ventricular tachycardia. RESULTS: Twenty-one (45%) patients had significant conduction disorders and received a prophylactic ICD. Among ICD recipients, no patient died suddenly and 11 (52%) patients required appropriate ICD therapy during a median follow-up of 62 months. Left ventricular ejection fraction was ≥45% in 9 patients at the time of the event. Among the 10 patients without malignant VA, device memory recorded nonsustained ventricular tachycardia in 8 (80%). The presence of significant conduction disorders was the only factor related to the occurrence of malignant VA (hazard ratio 5.20; 95% confidence interval 1.14-23.53; P = .03). CONCLUSIONS: Life-threatening VAs are common in patients with LMNA mutations and significant cardiac conduction disorders, even if left ventricular ejection fraction is preserved. ICD is an effective treatment and should be considered in this patient population.