Arrhythmic Risk in Biventricular Pacing Compared With Left Bundle Branch Area Pacing: Results From the I-CLAS Study.

BACKGROUND: Left bundle branch area pacing (LBBAP) may be associated with greater improvement in left ventricular ejection fraction and reduction in death or heart failure hospitalization compared with biventricular pacing (BVP) in patients requiring cardiac resynchronization therapy. We sought to compare the occurrence of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and new-onset atrial fibrillation (AF) in patients undergoing BVP and LBBAP. METHODS: The I-CLAS study (International Collaborative LBBAP Study) included patients with left ventricular ejection fraction ≤35% who underwent BVP or LBBAP for cardiac resynchronization therapy between January 2018 and June 2022 at 15 centers. We performed propensity score-matched analysis of LBBAP and BVP in a 1:1 ratio. We assessed the incidence of VT/VF and new-onset AF among patients with no history of AF. Time to sustained VT/VF and time to new-onset AF was analyzed using the Cox proportional hazards survival model. RESULTS: Among 1778 patients undergoing cardiac resynchronization therapy (BVP, 981; LBBAP, 797), there were 1414 propensity score-matched patients (propensity score-matched BVP, 707; propensity score-matched LBBAP, 707). The occurrence of VT/VF was significantly lower with LBBAP compared with BVP (4.2% versus 9.3%; hazard ratio, 0.46 [95% CI, 0.29-0.74]; P<0.001). The incidence of VT storm (>3 episodes in 24 hours) was also significantly lower with LBBAP compared with BVP (0.8% versus 2.5%; P=0.013). Among 299 patients with cardiac resynchronization therapy pacemakers (BVP, 111; LBBAP, 188), VT/VF occurred in 8 patients in the BVP group versus none in the LBBAP group (7.2% versus 0%; P<0.001). In 1194 patients with no history of VT/VF or antiarrhythmic therapy (BVP, 591; LBBAP, 603), the occurrence of VT/VF was significantly lower with LBBAP than with BVP (3.2% versus 7.3%; hazard ratio, 0.46 [95% CI, 0.26-0.81]; P=0.007). Among patients with no history of AF (n=890), the occurrence of new-onset AF >30 s was significantly lower with LBBAP than with BVP (2.8% versus 6.6%; hazard ratio, 0.34 [95% CI, 0.16-0.73]; P=0.008). The incidence of AF lasting >24 hours was also significantly lower with LBBAP than with BVP (0.7% versus 2.9%; P=0.015). CONCLUSIONS: LBBAP was associated with a lower incidence of sustained VT/VF and new-onset AF compared with BVP. This difference remained significant after adjustment for differences in baseline characteristics between patients with BVP and LBBAP. Physiological resynchronization by LBBAP may be associated with lower risk of arrhythmias compared with BVP.

First-in-man report of transsubclavian venous implantation of the Aveir leadless cardiac pacing system.

INTRODUCTION: Transsubclavian venous implantation of the Aveir leadless cardiac pacemaker (LCP) has not been previously reported. METHODS AND RESULTS: Three cases of transsubclavian implantation of the Aveir LCP are reported. Two cases were postbilateral orthotopic lung transplant, without appropriate femoral or jugular access due to recent ECMO cannulation and jugular central venous catheters. In one case, there was strong patient preference for same-day discharge. Stability testing confirmed adequate fixation and electrical testing confirmed stable parameters in all cases. All patients tolerated the procedure well without significant immediate complications. CONCLUSIONS: We demonstrate the feasibility of transsubclavian implantation of the Aveir LCP.

Anti-bradycardia pacing-impact on patients with HFpEF: a systematic review.

Heart failure with preserved ejection fraction (HFpEF) has become an emerging concern. The protective effect of bradycardia in patients with reduced ejection fraction using beta-blockers or ivabradine does not improve symptoms in HFpEF. This review aims to assess current data regarding the impact of anti-bradycardia pacing in patients with HFpEF. A search was conducted on PubMed, ScienceDirect, Springer, and Wiley Online Library, selecting studies from 2013 to 2023. Relevant and eligible prospective studies and randomized controlled trials were included. Functional status, quality of life, and echocardiographic parameters were assessed. Six studies conformed to the selection criteria. Four were prospective studies with a total of 90 patients analyzed. Two were randomized controlled trials with a total of 129 patients assessed. The 6-min walk test (6MWT) and the Minnesota Living with Heart Failure Questionnaire (MLHFQ) score improved in all prospective studies. My-PACE trial showed improvements in MLHFQ score (p < 0.001), significant relative lowering in NT-proBNP levels (p = 0.02), and an increased mean daily activity in the personalized accelerated pacing group compared to usual care. RAPID-HF trial proved that pacemaker implantation to enhance exercise heart rate (HR) did not improve exercise capacity and was associated with increased adverse events. HFpEF requires a more individualized approach and quality of life management. This review demonstrates that higher resting HR by atrial pacing may improve symptoms and even outcomes in HFpEF, while a higher adaptive rate during exertion has not been proven beneficial.

Dual-chamber vs. single-chamber pacemaker in patients in sinus rhythm with an atrioventricular block: a nationwide cohort study.

AIMS: In complete atrioventricular block (AVB) with underlying sinus rhythm, it is recommended to implant a dual-chamber pacemaker rather than a single-chamber pacemaker. However, no large-scale study has been able to demonstrate the superiority of this choice on hard clinical criteria such as morbimortality. METHODS AND RESULTS: This retrospective observational study included all patients who received a primary pacemaker implantation in the indication of complete AVB with underlying sinus rhythm in France, based on the national administrative database between January 2013 and December 2022. After propensity score matching, we obtained two groups containing 19 219 patients each. The incidence of all-cause mortality was 9.22%/year for the dual-chamber pacemaker group, compared with 11.48%/year for the single-chamber pacemaker group (hazard ratio (HR) 0.807, P < 0.0001]. Similarly, there was a lower incidence of cardiovascular mortality (HR 0.766, P < 0.0001), heart failure (HR 0.908, P < 0.0001), atrial fibrillation (HR 0.778, P < 0.0001), and ischaemic stroke (HR 0.873, P = 0.008) in the dual-chamber pacemaker group than in the single-chamber pacemaker group. Regarding re-interventions and complications, there were fewer upgrades (addition of atrial lead or left ventricular lead) in the dual-chamber group (HR 0.210, P < 0.0001), but more haematomas (HR 1.179, P = 0.006) and lead repositioning (HR 1.123, P = 0.04). CONCLUSION: In the indication of complete AVB with underlying sinus rhythm, our results are consistent with current recommendations to prefer implantation of a dual-chamber pacemaker rather than a single-chamber pacemaker for these patients. Implantation of a dual-chamber pacemaker is associated with a lower risk of mortality, heart failure, atrial fibrillation, and stroke during follow-up.

Making certain that noninvasive therapy for vasovagal syncope has failed before proceeding to invasive interventions.

There is a perceived need to express concisely the advice of guidelines in the context of consideration of invasive management of highly symptomatic vasovagal syncope. In response to this need the table is presented as a checklist and the text adds explanation and details. It is anticipated that this will prove to be of value for clinicians.

Mechanism-based therapy of non-cardiac syncope: a practical guide.

The term non-cardiac syncope includes all forms of syncope, in which primary intrinsic cardiac mechanism and non-syncopal transient loss of consciousness can be ruled out. Reflex syncope and orthostatic hypotension are the most frequent aetiologies of non-cardiac syncope. As no specific therapy is effective for all types of non-cardiac syncope, identifying the underlying haemodynamic mechanism is the essential prerequisite for an effective personalized therapy and prevention of syncope recurrences. Indeed, choice of appropriate therapy and its efficacy are largely determined by the syncope mechanism rather than its aetiology and clinical presentation. The two main haemodynamic phenomena leading to non-cardiac syncope include either profound hypotension or extrinsic asystole/pronounced bradycardia, corresponding to two different haemodynamic syncope phenotypes, the hypotensive and bradycardic phenotypes. The choice of therapy-aimed at counteracting hypotension or bradycardia-depends on the given phenotype. Discontinuation of blood pressure-lowering drugs, elastic garments, and blood pressure-elevating agents such as fludrocortisone and midodrine are the most effective therapies in patients with hypotensive phenotype. Cardiac pacing, cardioneuroablation, and drugs preventing bradycardia such as theophylline are the most effective therapies in patients with bradycardic phenotype of extrinsic cause.

Factors associated with cardiac implantable electronic device-related infections, New South Wales, 2016-21: a retrospective cohort study.

OBJECTIVES: To quantify the rate of cardiac implantable electronic device (CIED)-related infections and to identify risk factors for such infections. DESIGN: Retrospective cohort study; analysis of linked hospital admissions and mortality data. SETTING, PARTICIPANTS: All adults who underwent CIED procedures in New South Wales between 1 January 2016 and 30 June 2021 (public hospitals) or 30 June 2020 (private hospitals). MAIN OUTCOME MEASURES: Proportions of patients hospitalised with CIED-related infections (identified by hospital record diagnosis codes); risk of CIED-related infection by patient, device, and procedural factors. RESULTS: Of 37 675 CIED procedures (23 194 men, 63.5%), 500 were followed by CIED-related infections (median follow-up, 24.9 months; interquartile range, 11.2-40.8 months), including 397 people (1.1%) within twelve months of their procedures, and 186 of 10 540 people (2.5%) at high risk of such infections (replacement or upgrade procedures; new cardiac resynchronisation therapy with defibrillator, CRT-D). The overall infection rate was 0.50 (95% confidence interval [CI], 0.45-0.54) per 1000 person-months; it was highest during the first month after the procedure (5.60 [95% CI, 4.89-6.42] per 1000 person-months). The risk of CIED-related infection was greater for people under 65 years of age than for those aged 65-74 years (adjusted hazard ratio [aHR], 1.71; 95% CI, 1.32-2.23), for people with CRT-D devices than for those with permanent pacemakers (aHR, 1.46; 95% CI, 1.02-2.08), for people who had previously undergone CIED procedures (two or more v none: aHR, 1.51; 95% CI, 1.02-2.25) or had CIED-related infections (aHR, 11.4; 95% CI, 8.34-15.7), or had undergone concomitant cardiac surgery (aHR, 1.62; 95% CI, 1.10-2.39), and for people with atrial fibrillation (aHR, 1.33; 95% CI, 1.11-1.60), chronic kidney disease (aHR, 1.54; 95% CI, 1.27-1.87), chronic obstructive pulmonary disease (aHR, 1.37; 95% CI, 1.10-1.69), or cardiomyopathy (aHR 1.60; 95% CI, 1.25-2.05). CONCLUSIONS: Knowledge of risk factors for CIED-related infections can help clinicians discuss them with their patients, identify people at particular risk, and inform decisions about device type, upgrades and replacements, and prophylactic interventions.

Chronic clinical performance of a novel subxiphoidal pacemaker system: Early feasibility study design.

BACKGROUND: Extravascular and leadless pacemakers are a new class of cardiac devices that may reduce the rate of complications common to traditional cardiac pacemakers with intracardiac leads. These devices also have the potential of expanding access to cardiac pacing therapy by simplifying the complexity and cost of implantation. The objective of this study is to evaluate the implantation, chronic safety, and performance of a novel subxiphoidal pacemaker. METHODS: This study is an open-label, non-randomized, early feasibility study. Ten patients indicated for implantation of a single-chamber ventricular pacemaker will be enrolled and implanted with the investigational device. The pacemaker will be inserted underneath the ribcage and clipped to the xiphoid process, with stimulation electrodes positioned on the cardiac pericardium. Patients will be programmed to chronic pacing; pacing capture threshold, sensing amplitude, and lead impedance will be measured at implant and regularly scheduled follow-up visits. 24-h Holter ECG and cardiac troponin will also be periodically measured. Adverse events will be recorded throughout the study period. CONCLUSION: This study is designed to assess the feasibility, safety, and chronic performance of a novel extravascular pacemaker, and will provide valuable data on whether this device has the potential to be a viable alternative to conventional pacemakers.

Percutaneous extraction of a Micra AV transcatheter pacing system due to a rare sudden battery failure after 19 months from implantation: A first experience worldwide.

INTRODUCTION: Micra AV Transcatheter Pacing System (TPS) represents an innovative second-generation leadless pacemaker which represents an effective alternative to conventional devices in selected cases. Intrinsic malfunctions of these devices are rare, requiring sometimes their retrieval. When performed in experienced centers, this procedure is safe. CASE PRESENTATION: We describe a case of sudden battery malfunction of a Micra AV TPS, which required the extraction and the placement of a new pacing system in the right ventricle. DISCUSSION: This case, which has never been reported, highlights the need to a careful fluoroscopic evaluation and the usefulness of remote monitoring.

Transvenous lead advancement in pediatric pacing to overcome growth-induced lead straightening and stretching.

BACKGROUND: The stretching of the lead caused by somatic growth may lead to complications (dislodgement, fracture, failure) of transvenous leads implanted in pediatric patients. Atrial loop and absorbable ligatures may prevent it. Periodical lead advancement with lead pushing from the pocket may be an option to growth-induced stretching. Our aim was to analyze retrospectively the outcome of periodical transvenous lead advancement in children with pacemaker (PM). METHODS: A procedure of lead advancement was performed in patients with a single-chamber PM implanted for isolated congenital complete atrioventricular block or sinus node dysfunction with growth-induced lead straightening/stretching. The PM pocket was opened, the lead was released from subcutaneous adherences and was gently advanced to shape again a loop/semi-loop in the atrium without dislodging the tip. Lead data (threshold, sensing, impedance) were compared before and after the procedure. Data are described as median (25th-75th centiles). RESULTS: 14 patients with 13 VVIR and 1 AAIR PM implanted at 6.8 (5.9-8.0) years of age, 23 (19-26) kg, 118 (108-124) cm, underwent 30 advancement procedures, 1.5 (1.0-2.3) per patient, during follow-up [45 (35-63) months]. Delta between procedures was: 18 (14-25) months, 11 (7-13) cm, 6 (4-9) kg; 90% of leads were successfully advanced without complications. Three unsuccessful procedures occurred with longer times [30 (14-37) months]. Electrical lead parameters did not show significant differences pre-/post-procedures. CONCLUSION: the advancement of transvenous leads in children seems safe and effective. This procedure may be another possible choice to preserve transvenous lead position and function until growth has completed.

Left versus right ventricular pacing during TAVR and balloon aortic valvuloplasty: A systematic review and meta-analysis.

INTRODUCTION: While right ventricular pacing (RVP) is the conventional temporary pacing modality used for transcatheter aortic valve replacement (TAVR), this approach possesses inherent risks and procedural challenges. We aim to assess and compare the safety and efficacy of left ventricular pacing (LVP) and RVP during TAVR and balloon aortic valvuloplasty (BAV). METHODS: Following PRISMA guidelines, a comprehensive literature search was conducted in four databases from inception to December 15th, 2023. We included observational studies and clinical trials comparing LVP with RVP during TAVR and BAV procedures. Primary outcomes included short-term mortality, mortality due to cardiac tamponade, and procedural complications including bleeding, vascular complications, and cardiac tamponade. Secondary outcomes comprised procedure duration and length of hospital stay. RESULTS: Five studies involving 830 patients with RVP and 1577 with LVP were included. Short-term mortality was significantly higher in the RVP group (RR 2.32, 95% CI: [1.37-3.93], P = .002), as was the incidence of cardiac tamponade (RR 2.19, 95% CI: [1.11-4.32], P = .02). LVP demonstrated shorter hospital stays (MD = 1.34 d, 95% CI: [0.90, 1.78], P < .001) and reduced procedure duration (MD = 7.75 min, 95% CI: [5.08, 10.41], P < .00001) compared to RVP. New pacemaker implantation was higher in the RVP group (RR 2.23, 95% CI: [1.14, 4.39], P = .02). CONCLUSION: LVP during TAVR and BAV emerges a safer alternative to RVP, offering reduced mortality, hospital stays, and procedure durations.

The effectiveness and safety of temporary transvenous cardiac pacing leads placement into coronary sinus vein in patients with sick sinus syndrome.

BACKGROUND: The temporary pacing lead routinely is placed into right ventricular (RV), which pose a risk of dislocation and cardiac perforation. OBJECTIVE: We aim to evaluate the effectiveness and safety of temporary transvenous cardiac pacing (TTCP) leads placement into the coronary sinus vein (CSV) in patients with sick sinus syndrome (SSS). METHODS: We investigated patients with SSS who underwent TTCP lead placement into the CSV under the guidance of X-ray between January 2013 and May 2023. Patients were randomly divided into two groups: RV group (n = 33) and CSV group (n = 22). The ordinary passive bipolar electrodes were applied in both groups. In RV groups, electrodes were placed into RV. In CSV group, electrodes were placed into CSV. We evaluated the operation duration, fluoroscopic exposure, first-attempt success rate of leads placement, pacing threshold, success rate of leads placement, rate of leads displacement, and complications. RESULTS: Compared with that in RV group, the procedure time, fluoroscopic exposure was significantly prolonged, while the first-attempt success rate of lead placement was obviously increased in CSV group (both p < .05). Compared with that in RV group, the rate of leads displacement is lower in CSV group (both p < .05). There were three patients occurred cardiac perforation in RV group, but no cardiac perforation was reported in CSV group (p > .05). CONCLUSION: TTCP leads placement into the CSV is an effective and safe strategy in patients with SSS. It indicates a high rate of pacing effectiveness with low device replacement and complication rates.

Reply to the comments on "Effect of Bedside Ultrasound­Guided Versus Fluoroscopy­Guided Transvenous Cardiac Temporary Pacing in Children with Bradyarrhythmia".

The article "Effect of Bedside Ultrasound­Guided Versus Fluoroscopy­Guided Transvenous Cardiac Temporary Pacing in Children with Bradyarrhythmia" offers valuable insights into comparative short-term pacing strategies for pediatric bradyarrhythmias. There are some comments that the study overlooks the impact of genetic factors on bradyarrhythmias and treatment outcomes, lacks detailed information on the influence of medications, and does not address the cost-effectiveness of the pacing techniques. The analysis and explanation are made here, and it is hoped that through further research in the future, the conclusions will be more reliable.

Effect of Bedside Ultrasound-Guided Versus Fluoroscopy-Guided Transvenous Cardiac Temporary Pacing in Children with Bradyarrhythmia.

To compare the efficacy and safety of bedside ultrasound-guided and fluoroscopy-guided transvenous cardiac temporary pacing in the treatment of bradyarrhythmia in children. Children treated by temporary intravenous cardiac pacing from January 2016 to June 2023 in Hunan Provincial Children's Hospital were enrolled, and the characteristics and data of the cases were summarized. Patients were divided into bedside ultrasound-guided group (ultrasound group) and fluoroscopy-guided group (fluoroscopy group) according to the implantation guidance methods. The efficacy, safety, and incidence of complications in children were compared, and follow-up analysis was carried out. A total of 30 children were enrolled, including 18 males and 12 females, with a median age of 5.5 (2.9, 10.0) years and a median weight of 18.7 (12.7, 32.7) kg. The most common primary diseases were fulminant myocarditis (13/30 cases) and congenital high-grade AVB (10/30 cases). Among them, the proportion of congenital high AVB in the fluoroscopy group was significantly higher than that in the ultrasound group, and the difference was statistically significant (p = 0.007). The implantation process was successful in all 30 children. From the time of pacing decision to implantation, the median time of ultrasound group was 56 (30, 60) min and that of fluoroscopy group was 154 (78,180) min, with a statistically significant difference (P < 0.001). A total of 5 cases developed complications. There was no statistically significant difference between the two groups (P > 0.05). Compared with traditional fluoroscopic temporary pacing, bedside ultrasound-guided temporary pacing technology can effectively shorten the operation time and reduce the occurrence of complications and has become a better choice for children's emergency and critical care treatment. The right internal jugular vein is preferred for intravenous implantation.

Response to "Effect of Bedside Ultrasound­Guided Versus Fluoroscopy­Guided Transvenous Cardiac Temporary Pacing in Children with Bradyarrhythmia".

The article "Effect of Bedside Ultrasound­Guided Versus Fluoroscopy­Guided Transvenous Cardiac Temporary Pacing in Children with Bradyarrhythmia" offers valuable insights into comparative short-term pacing strategies for pediatric bradyarrhythmias. This letter commends the study for its relevance and potential to improve patient care but highlights several limitations. Notably, the study overlooks the impact of genetic factors on bradyarrhythmias and treatment outcomes, lacks detailed information on the influence of medications, and does not address the cost-effectiveness of the pacing techniques. Future research should address these aspects to enhance the validity and applicability of the findings.

Atrial Pacing Negatively Affects Left Atrial Morphological and Functional Parameters Similarly to Atrioventricular Dyssynchrony.

Background and Objectives: Atrioventricular (AV) dyssynchrony as well as atrial and ventricular pacing affect left atrial (LA) function. We conducted a study evaluating the effect of atrial and ventricular pacing on LA morphological and functional changes after dual-chamber pacemaker implantation. Materials and Methods: The study prospectively enrolled 121 subjects who had a dual-chamber pacemaker implanted due to sinus node disease (SND) or atrioventricular block (AVB). Subjects were divided into three groups based on indication and pacemaker programming: (1) SND DDDR 60; (2) AVB DDD 60 and (3) AVB DDD 40. Subjects were invited to one- and three-month follow-up visits. Three subsets based on pacing burden were analyzed: (1) high atrial (A) low ventricular (V); (2) high A, high V and (3) low A, high V. LA function was assessed from volumetric parameters and measured strains from echocardiography. Results: The high A, low V group consisted of 38 subjects; while high A, high V had 26 and low A, high V had 23. A significant decrease in reservoir and contractile LA strain parameters were only observed in the high A, low V pacing group after three months (reservoir 25.9 ± 10.3% vs. 21.1 ± 9.9%, p = 0.003, contractile -14.0 ± 9.0% vs. -11.1 ± 7.8, p = 0.018). While the re-established atrioventricular synchrony in the low A, high V group maintained reservoir LA strain at the baseline level after three months (21.4 ± 10.4% vs. 22.5 ± 10.4%, p = 0.975); in the high A, high V group, a further trend to decrease was noted (20.3 ± 8.9% vs. 18.7 ± 8.3%, p = 0.231). Conclusions: High atrial pacing burden independently of atrioventricular dyssynchrony and ventricular pacing impairs LA functional and morphological parameters. Changes appear soon after pacemaker implantation and are maintained.

Cardiac resynchronization therapy with conduction system pacing in a long-term heart transplant recipient: A case report.

We performed cardiac resynchronization therapy by means of conduction system pacing in a heart transplant patient suffering from heart failure with reduced ejection fraction and atrial fibrillation with conduction disturbance (bifascicular block and QRS >160 ms). ECG monitoring showed paroxysmal atrioventricular block. Biventricular pacing was not feasible due to the absence of a suitable coronary sinus branch for pacing. His bundle pacing was performed, and an implantable cardioverter-defibrillator was implanted due to severe left ventricular dysfunction. Cardiac allograft vasculopathy was excluded. During follow-up, the patient's left ventricular function improved, and symptoms alleviated with a high percentage of ventricular stimulation.

Optogenetically mediated large volume suppression and synchronized excitation of human ventricular cardiomyocytes.

A major challenge in cardiac optogenetics is to have minimally invasive large volume excitation and suppression for effective cardioversion and treatment of tachycardia. It is important to study the effect of light attenuation on the electrical activity of cells in in vivo cardiac optogenetic experiments. In this computational study, we present a detailed analysis of the effect of light attenuation in different channelrhodopsins (ChRs)-expressing human ventricular cardiomyocytes. The study shows that sustained illumination from the myocardium surface used for suppression, simultaneously results in spurious excitation in deeper tissue regions. Tissue depths of suppressed and excited regions have been determined for different opsin expression levels. It is shown that increasing the expression level by 5-fold enhances the depth of suppressed tissue from 2.24 to 3.73 mm with ChR2(H134R) (ChR2 with a single point mutation at position H134), 3.78 to 5.12 mm with GtACR1 (anion-conducting ChR from cryptophyte algae Guillardia theta) and 6.63 to 9.31 mm with ChRmine (a marine opsin gene from Tiarina fusus). Light attenuation also results in desynchrony in action potentials in different tissue regions under pulsed illumination. It is further shown that gradient-opsin expression not only enables suppression up to the same level of tissue depth but also enables synchronized excitation under pulsed illumination. The study is important for the effective treatment of tachycardia and cardiac pacing and for extending the scale of cardiac optogenetics.

Comparison of first- and second-generation leadless pacemakers in patients with sinus rhythm and complete atrioventricular block.

INTRODUCTION: The efficacy and safety of leadless cardiac pacemakers (LPMs) as an alternative to conventional transvenous cardiac pacing have been largely reported. The first generation of the MicraTM transcatheter pacing system (VR; Medtronic) was able to provide single-chamber VVI(R) pacing mode only, with a potential risk of pacemaker syndrome in sinus rhythm patients. A second-generation system (AV) now provides atrioventricular synchrony through atrial mechanical (Am) sensing capability (VDD mode). OBJECTIVE: We sought to compare VR and AV systems in sinus rhythm patients with chronic ventricular pacing (Vp) for complete atrioventricular block. METHODS: All consecutive patients implanted with an LPM in our department for complete atrioventricular block were retrospectively screened. Patients with atrial fibrillation, sinus dysfunction, or Vp burden <20% at 1 month postimplantation were excluded. Patients were systematically followed with a visit at 1 month, and then at least once a year. RESULTS: A total of 93 patients-45 VR (2015-2020) and 48 AV (2020-2021)-were included. VR and AV patients had similar baseline characteristics, except for VR patients being older (80 ± 8 vs. 77 ± 9 years, p = 0.049). The mean Vp burden was 77% in the VR and 82% in the AV group (p = 0.38). In AV patients, the median AV synchronous beats rate was 78%, with 65% having a >66% rate. An E/A ratio <1.2 as measured on echocardiography was the only independent predictor of accurate atrial mechanical tracking (p = 0.01). One-year survival rate was similar in both groups. Five patients in the VR and 0 in the AV group eventually developed pacemaker syndrome within 1 year post-implantation (p = 0.02). CONCLUSION: In sinus rhythm patients with chronic Vp for complete atrioventricular block implanted with an LPM, the atrial mechanical sensing algorithm allowed significant atrioventricular synchrony in most patients and was associated with no occurrence of-otherwise rare-pacemaker syndrome.

Feasibility and safety of left bundle branch area pacing in patients with septal hypertrophy.

INTRODUCTION: Left bundle branch area pacing (LBBAP) aims to provide physiological ventricular activation during pacing. Left ventricular septal hypertrophy (LVSH) might be challenging for LBBAP due to the thickness of the interventricular septum and potential presence of septal scar. This study assesses the feasibility, safety, and outcome of LBBAP in patients with LVSH using primarily stylet-driven leads (SDL). METHODS: Adult patients with LVSH who underwent LBBAP between March 2019 and November 2022 were enrolled. Baseline patient characteristics, procedural data and postprocedural results were collected. The feasibility of LBBAP in LVSH patients was compared to a cohort of LBBAP patients with normal septal wall thickness (NST). RESULTS: Seventeen LVSH and 133 NST patients underwent LBBAP with successful implantation achieved in 15 LVSH patients (88%). Mean implant depth was 17.2 ± 1.9 mm, with 53% proven left bundle branch (LBB) capture. Paced QRS duration (146 ± 14 ms) and V6 R-wave peak time (V6 RWPT; 79 ± 20 ms) were comparable between patients with and without septal hypertrophy, although patients with NST had higher rates of proven LBB capture (71% vs. 53%). In LVSH pacing thresholds (0.6 ± 0.3 V at 0.4 ms) and R-wave amplitude (13.9 ± 5.6 mV) were favorable and remained stable at follow-up. At 12 months, 87% of patients had stable or improved left ventricular ejection fraction. CONCLUSION: The results of the study indicate that LBBAP in patients with LVSH is safe and feasible and no lead-related complications were observed despite a mean implant depth exceeding 15 mm. LBBAP using SDL results in favorable pacing and electrocardiographic characteristics in LVSH patients, comparable to patients with NST.