Dual-chamber Devices Research Articles

DESCRIPCIÓN COMPLETA DE LOS MARCAPASOS CARDÍACOS. FUNCIÓN, TIPOS Y APLICACIONES CLÍNICAS.

Cardiac pacemakers are essential medical devices designed to manage arrhythmias by delivering electrical impulses to regulate heart rhythm. This comprehensive review explores their function, types, and clinical applications, emphasizing their role in improving patient outcomes. Modern pacemakers consist of a pulse generator and leads that transmit electrical signals to the myocardium, ensuring adequate cardiac output. The classification of pacemakers includes single-chamber, dual-chamber, and biventricular devices, each tailored to specific clinical needs. Single-chamber pacemakers stimulate either the atrium or ventricle, while dual-chamber devices coordinate atrial and ventricular contractions to mimic natural heart rhythm. Biventricular pacemakers, or cardiac resynchronization therapy (CRT) devices, are employed in patients with heart failure and ventricular dyssynchrony to improve systolic function and reduce symptoms. Indications for pacemaker implantation range from bradyarrhythmias, such as sick sinus syndrome and atrioventricular block, to advanced heart failure requiring CRT. Advances in technology have led to the development of leadless pacemakers and devices with extended battery life, offering minimally invasive options and reducing complications like lead fracture and infection. Additionally, some modern pacemakers incorporate remote monitoring capabilities, allowing clinicians to track device performance and patient status in real-time. Clinical decision-making regarding pacemaker selection and programming depends on patient- specific factors, including underlying cardiac pathology, comorbidities, and lifestyle. While the benefits of pacemakers are well-documented, potential complications, such as infection, lead dislodgement, or device malfunction, necessitate careful follow-up and management.

Abstract 4138640: Learning Curve for Left Bundle Branch Area Pacing Lead Implantation

Background: Left bundle branch area pacing (LBBAP) has shown promising outcomes at experienced centers, but less is known about the learning curve with new adoption of LBBAP. We conducted a retrospective analysis (2020-2023) of the learning curve for LBBAP at our center. Methods: Procedural success and complications in adult patients undergoing LBBAP by operators with >5-years’ experience in device implantation were compared between operators’ experience ≤10th (LBBAP inexp ) vs. >10th (LBBAP exp ) LBBAP implant. Successful LBBAP was defined as left ventricular activation time (LVAT) ≤80 ms. Results: Seven operators implanted LBBAP in 288 patients (age 73±11 years, 38% women): 68 (24%) in LBBAP inexp vs. 220 (76%) patients in LBBAP exp groups with similar baseline characteristics (all p >0.05). The median number of implants per operator was 22 (range 8-83). Table 1 shows the procedural characteristics and ECG results. Post-implant LVAT ≤80 ms was less frequent in LBBAP inexp compared to LBBAP exp (56.9% vs 72.4%, p=0.04, Figure 1 ). There were no differences in paced QRS duration ≤130 ms (75.9% vs. 76.1 %, p=1.0) or operator self-identified success (85% vs. 91%, p=0.2). With new single-/dual-chamber device implants, there was no difference in implant duration (103.4±31.8 vs. 101.6±38.5 minutes, p=0.3) but there was longer fluoroscopy in LBBAP inexp (12.6±10.1 vs. 8.2±8.0 minutes, p<0.0001, Figure 1 ). The average number of attempts at LBBAP was lower in LBBAP inexp vs. LBBAP exp (2.0 ± 1.5 vs. 2.9 ± 2.9, p=0.03). There was no difference in complications between the 2 groups ( Table 2 ). Conclusion: Operators use less fluoroscopy, make more attempts at LBBAP and more frequently achieve LVAT ≤80 ms after their first 10 implants.

Development of high-speed precision maize metering device for dense planting pattern with standard ridges.

This study proposed a high-speed precision dual-chamber maize metering device for the dense planting pattern with standard ridge promoted in China. Through theoretical analysis of the sowing process, parameters for the key components have been designed. The metering device is capable of planting two rows in a single pass for high-speed precision seeding. The effect of operating speed and negative pressure on seed metering quality was investigated. A high-speed camera was used to capture the trajectory of maize seed at different operating speeds, and it was found that intra-row shifts were caused by collisions at the mouth of the seed guide tube and rotation of the seed as it fell. Employing a two-factor, five-level orthogonal rotation test, Investigated the optimal operating parameters for the maize metering device. Response surface analysis showed that optimum seed metering quality was achieved at 14.2 km/h and 13.5 kPa. Validation tests showed a qualified rate of 97.93%, with a coefficient variation of 8.97% for this method. Additionally, an energy consumption analysis indicated a reduction in operating energy consumption of approximately 32% compared to conventional air suction seed metering devices for dense planting with large ridges on the same area of farmland. This study provides insights for reducing energy consumption in the seeding process, contributing to the sustainable development of agricultural resources.

A novel formula to assess the QT interval in ventricular paced rhythm

Abstract Background QT interval measurement in the presence of right ventricular pacing (RVP) represents a clinical challenge due to altered ventricular activation resulting in a prolonged QT-interval. The aim of this study is to compare the QT interval in patients before and after ventricular pacing to develop a new formula for QT interval assessment in patients with RVP. Methods and results All patients presenting to our pacemaker clinic with single- or dual chamber device were included in this prospective observational study. Inclusion criteria were no permanent right ventricular stimulation, an intrinsic QRS interval of <120 ms, and ventricular rate >35 bpm and <150 bpm. Three 12-lead electrocardiograms were recorded for each patient: during intrinsic rhythm and 2 following an atrial paced and a ventricular paced QRS at the same rate. The intrinsic QRS and QT time/JT time (QTi/JTi) were measured during intrinsic and subsequent RVP. To obtain the formula, all measurements were performed on 100 patients (mean age 74 ± 11.3, male 33%) (RV apical lead 30% and non-apical lead 70%). Based on our measurements, a new formula QT (non-paced) = 139.23 + 0.55 xQT (paced) was derived. A population of 482 individuals (mean age 75.5±13.2 years (SD), 64% male) with permanent RV pacing were used as a validation group. The intrinsic QRS and QT time were measured during SR and subsequent RVP. To assess the relationship between the predicted QT with RVP and the measured QT without RVP, linear correlations analyses were performed. Our formula had a strong correlation with the irrespective QT without RVP (r=0.50) Conclusion We proposed a new simple formula to accurately estimate QT during RVP. This formula can be easily utilized in clinical practice. Figure 1: MAD characteristic value via plots stands for Median Absolute Difference (i.e. by how many ms the prediction is estimated on average). Figure 2: "Forest Plot" illustrates the correlation coefficients in the form of a forest plot. The dot r represents r and the bars the 95% confidence intervalsMAD characteristic value via plots standForest Plot" illustrates the correlation

Innovations in Drug Delivery: From Microtechnology to Targeted Therapeutics

Drug delivery systems are developed to maximize drug efficacy and minimize side effects. As drug delivery technologies improve, the drug becomes safer and more comfortable for patients to use. The study on advanced drug delivery systems aims to increase patient compliance, decrease adverse effects, and improve treatment efficacy. Furthermore, the goal of these systems is to deliver drugs to particular body tissues or cells in a targeted manner, which should enhance treatment outcomes. During the last seven decades, extraordinary progress has been made in drug delivery technologies, such as systems for long-term delivery for months and years, localized delivery, and targeted delivery. In this review, we explain the general principles of several advanced drug delivery systems, their introduction objective, components, mechanism, functioning principle, and application. The implantable polymeric drug delivery system, cardiac pacemaker, prefilled dual chamber device, closed-loop insulin delivery system, hepatic infusion pumps, MEMS devices, inhaled insulin devices, and hydrogel-forming microneedles are among the medical devices that are being discussed in this article as being at the forefront of technological innovation in medicine. For a variety of medical diseases, these devices provide minimally invasive procedures, real-time monitoring, and more accurate drug delivery. The scope of medical treatment and monitoring procedures is changing due to the integration of cutting-edge materials and technology. By increasing convenience, decreasing adverse effects, and increasing efficacy, these cutting-edge solutions directly help patients. Furthermore, the adoption of advanced drug delivery systems has demonstrated promising results in enhancing patient compliance and treatment outcomes. By increasing the bioavailability and pharmacokinetics of pharmaceuticals, these systems have the potential to transform the fields of drug delivery and personalized medicine. However, the field also faces challenges in overcoming physicochemical barriers and biological unknowns. Challenges facing the advanced drug delivery systems industry include complicated formulation requirements, regulatory obstacles, and the need for new technologies to enhance patient outcomes and therapeutic efficacy. Strict intellectual property rules and competition from generic drug manufacturers can also directly hinder the expansion and financial success of businesses in this field. To progress, the field should focus on translatable research ideas, develop realistic goals, and most importantly, diversify technologies. This emphasis on diversity will inspire new ideas and approaches, leading to the development of more effective, patient-friendly drug delivery systems.

Chronic wireless communication between dual-chamber leadless pacemaker devices

BackgroundAveir DR (Abbott, Abbott Park, IL) is a dual-chamber leadless pacemaker (LP) system with distinct atrial and ventricular LPs (ALP, VLP) that communicate wirelessly to deliver atrioventricular synchronous pacing. Success rates of these implant-to-implant (i2i) transmissions have not been systematically evaluated. ObjectiveThis study aims to evaluate chronic i2i success rates in a clinical setting. MethodsPatients meeting standard dual-chamber pacing indications were enrolled and implanted with dual-chamber LP systems as part of a prospective international clinical trial (Aveir DR i2i Study). The percent of successful i2i transmissions from ALP-to-VLP (A-to-V) and VLP-to-ALP (V-to-A) were interrogated from LPs in de novo patients using the device programmer at implant, discharge, and at 1, 3, and 6 months postimplant (1M, 3M, 6M). ResultsA total of 399 patients completed device implant and i2i diagnostic interrogation (62% male; age 69 years; 65% sinus node dysfunction, 32% atrioventricular [AV] block). Median A-to-V and V-to-A i2i success rates exceeded 90% of beats at all time-points from implant to 6M. The minority of patients with A-to-V or V-to-A i2i success in <70% of beats at implant (A-to-V: 19% of patients, V-to-A: 31% of patients) showed roughly 40% improvement by 1M, with this minority dropping to roughly 5% of patients by 6M. Improvement in i2i communication success may be attributed to reprogramming of i2i setting levels, natural changes in dominant posture, and device stabilization. ConclusionWireless implant-to-implant communication in the new dual-chamber leadless pacemaker system demonstrated successful transmissions in >90% of beats throughout the 6-month evaluation period. Communication success improved significantly over time postimplant for specific subgroups. Clinical Trial RegistrationAveir DR i2i Study, ClinicalTrials.gov ID NCT05252702.

Oxidative stress and mitochondrial function among various types of atrial fibrillation

Abstract Introduction Mitochondrial dysfunction has been shown to be associated with atrial fibrillation (AF) in previous studies. Purpose We aimed to determine mitochondrial function in various AF types and AF burden to further delineate whether mitochondrial function has graded or quantal response relationship with AF. Methods This is a cross-sectional study in patients with atrial high-rate episode (AHRE) or AF who have dual-chamber cardiovascular implantable electronic device (CIED). Patients were categorized into clinical AF and subclinical AF. AF burden was measured as AHRE via CIED interrogations. Oxidative stress and mitochondrial function were determined in peripheral blood mononuclear cells (PBMCs). Results There was a total of 54 CIED patients. Mean age was 69.9+12.8 years. There were 9 (16.7%) patients with diabetes mellitus and 36 (66.7%) patients with history of clinical AF. After adjusting with multiple linear regression for age, left ventricular ejection fraction, glomerular filtration rate, history of AF, and diabetes mellitus, we found that clinical AF, as compared to subclinical AF, was independently associated with lower non-mitochondrial respiration (20.8, 6.5-35.6 vs. 48.0, 14.0-60.9 pMol/min, p=0.021) (median, IQR); lower basal respiration (72.1, 47.4-94.4 vs.97.2, 52.1-152.6 pMol/min, p=0.020); and lower ATP production (57.3, 24.7-73.2 vs. 78.6, 45.7-112.0 pMol/min, p=0.014) (Table 1). However, AF burden was not associated with alterations in oxidative stress and mitochondrial function. Conclusions Mitochondrial function from PBMC was significantly lower in patients with clinical AF compared to those with subclinical AF. However, there was no association between AF burden and the change in mitochondrial function. The study revealed a quantal response relationship between PBMC’s mitochondrial function and AF.

Outcomes of tine-based leadless pacemakers retrieval: a multicenter study

Abstract Background Leadless cardiac pacemakers (LCP) are well established in daily practice and comparable in safety as well as efficacy to conventional transvenous pacemakers. With increasing implant volumes, more patients may need extraction and retrieval of these devices. Data on extractability of LCPs is however scare. Purpose The aim of this study is to analyze indication, techniques, efficacy and safety of LCP extractions in a multicenter international registry. Methods This is an international, multicenter retrospective registry. Demographic parameters, indication of LCP extraction, success and complication rate were analyzed. Results A total of 50 patients (median age 71 years (IQR 64-81), 34% female) were included in this study. 52% of patients received the LCP for complete AV block. The primary underlying cardiac condition was coronary artery disease in 42%. The main indication for LCP extraction was rise in threshold with loss of capture (32%), upgrade to biventricular pacemaker (26%) or upgrade to transvenous dual-chamber device (14%) (Figure 1). The overall success rate of device extraction was 96% with a mean dwell time of the LCP of 715 days (range 0-1477 days). In most cases, a steerable sheath with a single loop snare (71%) was used (Figure 2). Procedure related adverse events were low and included two pericardial effusion (not requiring any intervention) and one case of a device embolization that was retrieved successfully in the same setting. Overall mortality at 7 days was 0 %. Conclusion Retrieval/extraction of chronically implanted LCP appear to be safe and feasible in centers with expertise in femoral snaring.Indication for LCP retrievalTools used for LCP extraction

Modern physiological approach to inappropriate ICD shocks due to atrial fibrillation with very fast ventricular response. A case report

BackgroundFast-conducting atrial fibrillation misinterpreted as ventricular tachycardia is the leading cause for inappropriate shocks in patients with implantable cardiac defibrillators (ICD). These inappropriate shocks are associated with significant morbidity and mortality and cause great discomfort and stress.Case presentationWe report the case of a patient with ischemic cardiomyopathy, permanent atrial fibrillation, and a single-chamber DF-1 ICD implanted for the primary prevention of sudden cardiac death, who presented for multiple inappropriate internal shocks due to very fast-conducting atrial fibrillation, which was mislabeled as ventricular fibrillation by the ICD. Since the patient was under maximal atrioventricular nodal blocking medical therapy (beta-blockers and digitalis) and we didn`t find any reversible causes for the heart rate acceleration, we opted for rate control with atrioventricular node ablation. To counteract the risk of pacing-induced cardiomyopathy in this patient who would become totally pacemaker-dependent, we successfully performed left bundle branch area pacing. Because the patient`s ICD had a DF-1 connection and the battery had a long life remaining, we connected the physiological pacing lead to the IS-1 sense-pace port of the ICD. The 6-month follow-up showed an improvement in left ventricular function with no more inappropriate shocks.ConclusionsLeft bundle branch area pacing and atrioventricular node ablation in patients with an implantable single-chamber DF-1 defibrillator and fast-conducting permanent atrial fibrillation is a cost-efficient and very effective method to prevent and treat inappropriate shocks, avoiding the use of an additional dual-chamber or CRT-D device.

New Onset Dyspnea in a Patient with Pacemaker, What Does the ECG Tracing Show?

Dual chamber pacemakers are programmed to allow for AV synchrony. Whenever a patient with a dual chamber pacemaker with underlying sinus rhythm presents with AV dissociation, the lack of AV synchrony should be questioned. The authors present a case of new onset dyspnea diagnosed as pacemaker syndrome. The diagnosis was initially delayed due to underlying ventricular paced rhythm as misidentified as normal pacemaker behavior. A 69-year-old female with a past medical history of 2:1 atrioventricular block status post dual-chamber pacemaker implant presented with complaints of new onset shortness of breath and dyspnea. The ECG showed a ventricular rate of 66 beats per minute. Pacing spikes were prior to each QRS complex indicating ventricular-paced rhythm with left bundle branch morphology. There were p waves from sinus origin which were completely dissociated from the ventricular paced rhythm. Overall, there was ventricular paced rhythm with underlying AV dissociation. This was initially suspected to be normal pacemaker behavior as there was appropriate ventricular pacing and ventricular capture. Review of the tracing noted AV dissociation, which would be unusual in a patient with underlying sinus rhythm and dual chamber device. Device interrogation noted that device was at end of life and atrial lead was powered down to allow for ventricular pacing. It is important to always question the lack of AV synchrony if patients have dual chamber pacemaker as lack of AV synchrony can cause pacemaker syndrome.

Cardiac Implantable Electronic Device (CIED) Infections, Associated Risk Factors and Optimization in Reducing CIED Infections; An Experience of Tertiary Care Hospital of Pakistan

Objective: To determine the frequency of infections in cardiac implantable Electronic device patients, identify risk factors, and look for optimization in reducing Cardiac Implantable Electronic Device infections, with a resultant decrease in mortality and morbidity, decrease in hospital stay, and total expenditure. Study Design: Cross-sectional study. Place and Duration of Study: Electrophysiology Department of National Institute of Cardiovascular Diseases, Karachi Pakistan, from Jul 2019 to Jun 2020. Methodology: The study was conducted on the patients with cardiac implantable devices. Adult patients of either genderwith cardiac implantable Electronic device and infection were included. Epicardial leads and surgical site infections within six weeks were excluded. Results: One thousand and forty-six (1046) patients were enrolled in the study. There were 596(57%) male patients. 385(36.8%) patients were implanted with single chamber pacemakers, 390(37.3%) with dual chamber pacemakers, 146(14%) single chamber ICD (implantable cardiac defibrillator), 67(6.4%) dual-chamber cardiac implantable Electronic device, 46(4.4%) CRT-D, 12(1.1%) TPM, 134(12.8%) Re-do, 114(10.9%), 114(10.9%) generator change, 20(1.9%) leads revision, 26(2.5%) patients had extraction. The rate of CIED infection was 34(2.1%). The association of the study parameters with infection rate revealed that type of device (p=0.002), extraction, suture type, and post-procedure hematoma (p&lt;0.001) had a statistically significant relationship with infection rate.Conclusion: The Cardiac Implantable Electronic Device infection rate was 2.1%. Hypertension and diabetes were common risk factors, and left ventricular dysfunction was common in high-energy devices with multiple leads and repeated procedures.

Single-Chamber and Dual-Chamber Pacemaker Devices in Adults with Moderate and Complex Congenital Heart Disease: A Single Tertiary Referral Center Experience.

The number of device implantation procedures has increased in adult patients with congenital heart disease (ACHD). Despite significant improvements in materials and implantation techniques, these patients are exposed to higher risk of device related complications than general population. Herein, we describe our single tertiary referral center experience on transvenous pacemaker (PM) implantation and follow-up in adult patients with moderate and complex congenital heart disease (CHD) as limited data are available on long-term outcome. We considered all adults with moderate and complex CHD aged more than 16 years who underwent transvenous single-chamber and dual-chamber PM implant for sinus node dysfunction or atrioventricular block between January 2013 to December 2022 at our Unit. Seventy-one ACHD patients were included in the study (mean age 38.6 ± 15.2 years, 64% with moderate CHD, 36% with complex CHD). Among 32 patients implanted with a dual chamber PM (DDD PM), 4 devices were reprogrammed in VDD mode, 3 in VVI and 2 in AAI mode during follow-up because of lead dysfunction or permanent atrial arrhythmia. In addition, 26 patients had a single chamber PM (AAI or VVI PM) and 13 patients had single-lead pacing system with a free-floating atrial electrode pair (VDD PM). Just one of 13 single-lead VDD PM was reprogrammed in VVI mode due to a low atrial sensing. In DDD PM group, 10 re-interventions were needed due to lead dysfunction (8 cases) and lead-related infective endocarditis (2 cases). Only 3 patients in the single-lead PM group developed lead dysfunction with 2 re-interventions needed, but no infective endocarditis was reported. The rate of long-term complications is high in moderate and complex ACHD with transvenous PM devices, and it is mainly lead-related. In our experience, the less leads implanted, the less complications will occur. Considering the heterogeneity of the ACHD population, transvenous single-chamber or dual-chamber PM device implantation should always be tailored on the single patient, balancing risks and benefits in this complex population.

Cardiac implantable electronic devices in Bulgaria: results from the electronic registry BG-Pace for 2022

The current study analyses the activity on cardiac pacing in Bulgaria in 2022 based on data derived from a national registry of patients with cardiac implantable electronic devices (CIEDs).&amp;nbsp;Materials and methods.&amp;nbsp;Data from the national registry BG-Pace for 2022 was studied retrospectively. Demographic data, procedure and device type, pacing mode, etiology, symptoms, preimplantation ECG, number of implantations, and centre and operator volumes were analyzed.&amp;nbsp;Results:&amp;nbsp;Four thousand seven hundred seventy devices were implanted by 45 operators in 30 centers. Median age was 76 (IQR 69-82, 14-98) years, and male patients were 2843 (59,6%). The most significant number of implantations were carried out in the age group 70-79 years. The most commonly implanted CIEDs were antibradycardia devices - 578,8/million. Of them, conduction system pacing was used in 111 (2.3%). Implanted cardioverter-defibrillators demonstrated a growth compared to previous periods and reached 31.9/million. Cardiac resynchronization defibrillators implantations also shown a growth to 15.9/million. A considerable increase was found with implantable loop-recorders, which reached 8.8/million. Number of implantations per center was 115.5 (IQR 53-261.,3, 3-546), and 76,5 (IQR 36,8-154,8, 3-364) devices per operator. Dual chamber devices were most commonly implanted with a share of 83.1% in AVB I and II degrees, 72.5% in complete AVB, 82.6% in intraventricular conduction disturbances, and in 66.8% in patients with sick sinus syndrome. Pacing modes allowing for atrial sensing were most frequently implanted &amp;ndash; 62.4% of all implantations for conduction disturbances. There was a significant increase in the use of VVI mode with increasing age (P&lt;0.001).&amp;nbsp;Conclusion:&amp;nbsp;The national registry BG-Pace includes systematic clinical, demographical, and procedural&amp;nbsp;data for CIED implantations in Bulgaria. There is a growth in the implantation rates compared to previous periods, but they remain lower than the average number for Europe.

Long-term follow-up of the patients with pacemaker leads implanted through persistent left superior vena cava

Introduction/Objective. Persistent left superior vena cava (PLSVC) is the most common congenital malformation of the thoracic venous system and may often complicate cardiac implantable electronic device (CIED) lead implantation. The purpose of this study was to assess feasibility and safety of CIED lead implantation through PLSVC and its long-term efficacy. Methods. This is a retrospective observational study performed in a tertiary center from July 2005 to July 2019 among patients with fully successful implantation of all intended CIED leads through PLSVC. Results. CIED implantation was successfully completed with left-side approach in 26 of 32 (81.3%) patients with PLSVC. The average implantation time was 62, 73.5, 120, 74, 103.3, and 130 minutes and the average fluoroscopy time was 13.3, 20.8, 35.7, 17.1, 45.6, and 42.6 minutes for single and dual-chamber pacemakers, ICD-VR, ICD-DR, CRT-P, and CRT-D devices, respectively. The average follow-up period was 43.5 ? 29.9 months. During the follow-up period no CIED leads-related complications were noticed. Conclusion. The results of our study showed that the presence of PLSVC is not an obstacle for CIED implantation. The long-term follow-up proved stability of CIED leads implanted through PLSVC.

Test on adsorption posture and seeding performance of the high-speed precision dual-chamber maize metering device based on the seed characteristics

This study introduced a high-speed precision dual-chamber maize seed metering device and examined the impact of irregular-shaped holes on the planting quality in order to enhance the precision of maize planting. Based on the characteristic dimensions of maize seeds, the horizontal-profiled seed metering plates, lateral-profiled seed metering plates, vertical-profiled seed metering plates, and round-hole seed metering plates were developed. This research examined how the performance of individual seed metering plate types is affected by varying forward velocity and negative pressure conditions. Utilizing high-speed camera technology, statistical analysis was conducted on the adsorption posture data of maize seeds with different hole shapes. It was found that the qualified index showed a positive correlation with the quantity of seeds in the horizontal posture, while the quantity of seeds in the lateral posture and vertical postures collectively influenced the multiples index and the miss index. This research explored the optimal operating parameters for the high-speed precision dual-chamber maize seed metering device, with a forward velocity of 15 km/h and a negative pressure of 14 kPa. The validation tests yielded the qualified index of 98.13 %, the multiples index of 1.19 %, and the miss index of 0.68 %. This study offers insight for developing different seed metering devices based on seed characteristic dimensions, while also offers insights into the mechanism for improving the seeding quality of high-speed precision seed metering devices.

Conversion to Sinus Rhythm in Refractory Atrial Fibrillation Patients after Atrioventricular Node Ablation with Conduction System Pacing.

"Ablate and pace" strategy is a reasonable treatment option in refractory atrial fibrillation (AF) when sinus rhythm (SR) cannot be achieved with catheter ablation or pharmacological therapy. Atrioventricular node ablation (AVNA) combined with conduction system pacing (CSP), with left bundle branch pacing (LBBP) or His bundle pacing (HBP), is gaining recognition since it offers the most physiological activation of the left ventricle. However, the incidence of conversion to SR after AVNA with CSP is not known. The purpose of the investigation was to determine the incidence of spontaneous conversion to SR and its predicting factors in patients undergoing CSP and AVNA. Consecutive refractory symptomatic AF patients undergoing AVNA with CSP at our institution between June 2018 and December 2022 were retrospectively analyzed. Twelve lead electrocardiogram (ECG) recordings were analyzed at each outpatient follow-up visit. Echocardiographic and clinical parameters were assessed at baseline and six months after the implantation. Sixty-eight patients (male 42.6%, age 71 8 years, left ventricular ejection fraction 40 15%) were included. Thirty-seven patients (54.4%) received HBP and 31 (45.6%) LBBP. During follow-up, spontaneous conversion to SR was registered in 6 patients (8.8%); 3 in the HBP group and 3 in the LBBP group. Baseline characteristics of patients who converted to SR did not differ from non-sinus rhythm (NSR) patients except for left atrial volume index (LAVI), which was significantly smaller in the SR group (45 mL/ (41-51) vs. 60 mL/ (52-75); p = 0.002). Multiple regression model confirmed an inverse association between LAVI and conversion to SR even after considering other clinically relevant covariates (odds ratio 1.273, p = 0.028). At follow-up, LAVI did not change in any group (SR: p = 0.345; NSR: p = 0.508). Improvement in New York Heart Association (NYHA) class was comparable in both groups. Spontaneous conversion to SR after AVNA combined with CSP is not uncommon, especially in patients with smaller left atria. Further studies are warranted to clarify which patients should be considered for initial dual-chamber device implantation to provide atrio-ventricular synchrony in case of SR restoration.

Abstract 18100: Comparative Analysis of Right Ventricular (RV) Apical Pacing versus Physiologic Left Bundle Branch Area Pacing (LBBAP) in Hypertrophic Cardiomyopathy With Left Ventricular Outflow Tract Obstruction (LVOTO): A Case Study

Introduction: AV dyssynchrony is considered advantageous in HoCM patients requiring pacemaker therapy. The impact of physiologic pacing, particularly LBBAP, on LVOTO in HoCM remains unexplored. We present a patient highlighting the effect of LBBAP on LVOTO. Case: A 69-year-old female with HoCM (resting gradient ~130mmHg) and asymmetric septal hypertrophy (17mm), managed conservatively due to high surgical risk. She had persistent AF, accompanied by debilitating fatigue and palpitations. Due to unsuccessful treatment with sotalol, dofetilide, and 5 DCCV procedures, other treatment options were discussed. She opted for LBBA pacing and AV node ablation. Dual chamber device was implanted utilizing a Medtronic 3830 lead. Within 48 hours of discharge, she came to the ER with exertional dyspnea and lightheadedness, indicating ambulatory cardiogenic shock (BP: 78/66 mmHg). A stat echo showed LVEF of 75%, severe SAM, LVOT gradient of 179 mmHg, and severe MR. No pericardial effusion. Phenylephrine was initiated, and VVIR rate was decreased from 90 bpm to 60 bpm, but no BP improvement. Obstructive cardiogenic shock from worsened LVOTO was likely caused by physiologic LBBAP. To objectively demonstrate this, she underwent a brief study in the lab after informed consent. We inserted a temporary RV apical pacing lead and assessed LVOT gradients at rest and during exercise for both physiologic pacing and RV apical pacing. RV apical pacing had lower LVOT gradient at rest and exercise compared to LBBA pacing (Figure 1). LBBA lead was extracted and a CRT-P device implanted and programmed for optimal dyssynchrony. Discussion: Traditional RV apical pacing is superior to physiologic LBBAP in HoCM. Limited studies suggest biventricular pacing reduces LVOT gradient, but CRT is not superior to RV pacing. LBBA pacing may be contraindicated in LVOTO patients. Conclusion: In HCM patients with LVOTO, RV apical pacing appears superior to LBBAP, reducing LVOT gradient at rest and during exercise.

Frame-rate reduction to reduce radiation dose for cardiac device implantation is safe.

Radiation exposure to patient and surgeon during cardiac implantable electrical device (CIED) procedures remains a substantial health hazard to date. Advanced technical options for radiation dose reduction often pose considerable financial hurdles. We propose a near-zero cost, low-effort modification to a clinical x-ray system significantly reducing radiation dose during CIED implantation. We aim to evaluate a reduced frame rate protocol in CIED implantation for complication rates and reduction in radiation exposure. Starting May 2019, the frame rate during CIED implantations at our hospital was halved from 7.5 frames/s to 3.8 frames/s, and no further technical changes were made. During the following year, 264 patients were operated using this protocol and retrospectively compared with 231 cases implanted in the year before the protocol change, totaling 495 cases. Of these, 17%, 63%, and 19% were single-chamber, dual-chamber, or resynchronization devices, respectively. Incidence of complication prior to hospital discharge was considered the primary endpoint of the analysis. Radiation dose and procedural parameters were secondary endpoints. There was no increase in complications with the reduced frame rate protocol. Regression analysis further supported that the reduced frame rate radiation protocol was not associated with complication rates. Radiation exposure measured as dose area product was significantly reduced by ∼62% (median 369 [interquartile range 154-1207] cGy·cm2 via the reduced frame rate protocol vs median 970 [interquartile range 400-1906] cGy·cm2 with the standard frame rate; P < 0.01). A reduction of frame rate during CIED implantation is safe in terms of complication incidence and effective in terms of reducing radiation exposure.

Incidence of conversion to sinus rhythm in refractory atrial fibrillation patients after atrioventricular node ablation with conduction system pacing

Abstract Funding Acknowledgements Type of funding sources: None. Background "Ablate and pace" strategy is a reasonable therapeutic option in refractory atrial fibrillation (AF) when rhythm or rate control cannot be achieved with catheter ablation or pharmacological therapy. Atrioventricular node ablation (AVNA) combined with conduction system pacing (CSP), including His-bundle pacing (HBP) and left bundle branch pacing (LBBP), are increasingly adopted, as they offer more physiological activation of the left ventricle compared to other pacing modalities. However, the incidence of conversion to sinus rhythm after "ablate and pace" strategy with CSP is not known. Purpose To determine the incidence of spontaneous conversion to sinus rhythm and its predicting factors in patients undergoing AVNA and CSP. Methods Refractory AF patients undergoing AVNA with CSP at our institution between June 2018 and May 2022 were prospectively included. Echocardiographic and clinical parameters including ECG were assessed at baseline and 6 months after the procedure. Results Sixty-three patients (male 41.3%, age 71±9 years, left ventricle ejection fraction (LVEF) 40% (IQR 20)) were included. Thirty-seven patients (58.7%) received HBP and 26 patients (41.3%) LBBP. During follow-up, spontaneous conversion to sinus rhythm (SR) was registered in 5 patients (8%); 3 in HBP group and 2 in LBBP group. Baseline characteristics of patients who converted to SR did not differ from non-sinus rhythm (NSR) patients except for left atrial volume index (LAVI), which was smaller in SR group (43 mL/m2 (IQR 6) vs. 60 mL/m2 (IQR 19); p&amp;lt;0.01). Multiple regression model confirmed an inverse association between LAVI and conversion to sinus rhythm even after considering other clinically relevant covariates (odds ratio=0.685, p=0.03). At follow-up, LAVI did not change in any group (SR: p=0.345; NSR: p=0.508). LVEF increased in both groups, from 40% (IQR 20) to 51% (IQR 18) in NSR group (p&amp;lt;0.01) and from 41% (IQR 11) to 54% (IQR 11) in SR group (p=0.138), although the increase in SR group did not reach statistical significance due to small sample size. Similarly, ESVi decreased in both groups; in NSR group (from 47 mL/m2 (IQR 33) to 29 mL/m2 (IQR 24), p&amp;lt;0.01) and in SR group (from 33 mL/m2 (IQR 19) to 25 mL/m2 (IQR 0), p=0.176), where statistical significance was not reached due to small sample size and small initial volumes. Symptomatic improvement according to NYHA class was more pronounced in SR group (p=0.026). Conclusion The results of our study show that spontaneous conversion to sinus rhythm after AVNA combined with CSP is not uncommon, especially in patients with smaller left atria. Patients who converted to SR showed superior symptomatic improvement compared to NSR patients. Larger studies are warranted to clarify the predicting variables of SR restoration in these patients, which should be considered for initial atrial pacing lead implantation (dual-chamber device) when "ablate and pace" strategy is adopted.

Self-taught ultrasound-guided axillary vein access for pacemaker implantations - complication rates and outcomes

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac implantable electronic devices (CIEDs) are the mainstream therapy for advanced atrioventricular block or sustained ventricular arrhythmia. EHRA survey (1) showed that cephalic vein dissection and blind subclavian vein puncture are the preferred techniques for the implantation of CIED leads in European centres. Ultrasound (US) guided axillary puncture has emerged as feasible alternative for safe and rapid venous access for lead implantation. However, insufficient evidence to support its widespread adoption. Aim To compare the complication rates and clinical outcomes of CIED implantations utilising self-taught US guided axillary puncture versus non-US guided venous access (Subclavian puncture and fluroscopy guided axillary puncture). Assess the mean time to gain venous access and overall success rate in US guided technique. Methods Retrospective , observational study across two sites involving all CIED implantations of four experienced implanters over the year from January 2021 - June 2022. Patient's demographics, venous access time, complications and clinical outcomes were extracted from electronic database. US axillary access technique was self-taught. Results and Outcomes Venous access was obtained by US Guided axillary puncture in 146 patients, non-US guided in 208 patients. Successful axillary venous access by ultrasound guidance is 97%(146/151) with mean time to venous access of 2.1 minutes. Baseline demographics (age, gender) and comorbidities (hypertension, diabetes, cardiomyopathy, coronary artery disease, dyslipidemia, renal failure, oral steroid use, nicotine use) were similar between both US-guide and non-US guided groups, usage of oral anticoagulations (32.9% vs 39.4%,p=0.208) and antiplatelet agents(28.1% vs 35.1%,p=0.164) were not statistically different. Greater proportion of dual chamber pacemakers were implanted in US guided access group versus non-US guided (39.7% vs 27.9%,p=0.015). US Guided axillary access resulted in lower overall complication rate (2.1% vs 8.9%, p=0.0196): lower risk of pneumothorax (0% vs 3.8%,p=0.0236), lower risk of haemathoma (0% vs 3.4%,p=0.0448). No difference in short term pocket/lead infection or lead displacement. Severe vascular complications remains low in both groups. Stepwise binary regression analysis demonstrated US guidance as independent predictor of lower overall complication rate, odd-ratio 0.195 (95% CI 0.054 - 0.706). Summary: This multi-centered, retospective observational study demonstrated that US guided axillary access has high overall success rate, not time consuming and resulted in lower complication rates (especially pneumothorax and pocket haemathoma), despite the US access technique being self-taught and have greater proportion of dual chamber device implantations. US guided axillary access is demonstrated to be independently associated with 5-fold lower risk of complications.