Leadless Pacemaker Research Articles

Nearly half a century of cardiac pacing evolution: A patient's journey through epicardial, transvenous, and leadless pacemakers.

Nearly half a century of cardiac pacing evolution: A patient's journey through epicardial, transvenous, and leadless pacemakers.

Helix-fixation leadless pacemaker as a potential alternative to conventional transvenous pacemaker in post-Mustard baffle stenosis.

Obstruction of a systemic venous pathway is relatively common after the Mustard operation. A helix-fixation leadless pacemaker was successfully implanted in the subpulmonic but morphologic LV in a d-TGA patient with post-Mustard baffle stenosis and failure of a previously implanted epicardial lead.

Jugular Approach for the Transcatheter Pacemaker Implant - Better Access for Smaller Hearts?

The Micra leadless pacemaker was developed to fit inside the right ventricle, thereby reducing overall complications by 48% compared with a historical control group. The current labeling restricts implants to the femoral approach. In this article we used 3-dimensional computer models of human hearts to demonstrate why implants can be difficult in small patients and how using the jugular approach reduces these difficulties.Methods and Results: Cardiac computed tomography scans were made of 45 pacemaker patients, 26 in the US and 19 from a single center in Japan. Dimensional measurements were taken in all 45 hearts, and these dimensions were compared between patient cohorts and between the Micra delivery tool dimension and patient heart dimensions. Hearts were smaller among patients in the Japanese than US cohort. In addition, the tool dimension exceeded heart dimensions in a larger percentage of hearts from Japanese patients. Three dimensions were identified that most likely limit navigating across the tricuspid valve to the right ventricle in smaller hearts and for which the jugular approach improved navigation. Although the femoral procedure today maintains an excellent safety profile and procedure experience for most global implants, this study provides the rationale as to why the jugular approach may improve the ease of the Micra implant in small hearts, namely by reducing the tortuosity of the navigation across the tricuspid valve.

New Approach Concept of Leadless Pacemaker Implantation for Smaller Hearts.

New Approach Concept of Leadless Pacemaker Implantation for Smaller Hearts.

The Effectiveness and Safety of Leadless Pacemakers: An Updated Meta-Analysis.

Leadless pacemakers (LPs) are promising alternatives to traditional transvenous pacemakers (TVPs), but their comparative effectiveness and safety in clinical outcomes remain uncertain. We systematically searched PubMed, Embase, Scopus, Cochrane, and ClinicalTrials.gov for studies comparing LPs and TVPs. A restricted maximum likelihood random-effects model was used for all outcomes. Heterogeneity was assessed using I2 statistics. We performed a subgroup analysis with studies with multivariate-adjusted data. We included 21 studies involving 47,229 patients, of whom 12,199 (25.8%) underwent LP implantation. Compared with TVPs, LPs were associated with a significantly lower risk of overall complications (OR 0.61; 95% CI 0.45-0.81; p < 0.01), dislodgement (OR 0.34; 95% CI 0.20-0.56; p < 0.01), and pneumothorax (OR 0.27; 95% CI 0.16-0.46; p < 0.01). No significant difference in all-cause mortality was observed in the overall analysis (OR 1.43; 95% CI 0.65-3.15; p = 0.35) and in studies with multivariate-adjusted data (OR 1.34; 95% CI 0.65-2.78; p = 0.43). However, LPs were associated with a higher risk of pericardial effusion (OR 2.47; 95% CI 1.39-4.38; p < 0.01) and cardiac tamponade (OR 3.75; 95% CI 2.41-5.83; p < 0.01). LPs also demonstrated a lower pacing capture threshold (MD -0.19V; 95% CI [-0.23V]-[-0.16V]; p < 0.01), but no significant difference in impedance (MD 32.63 ohms; 95% CI [-22.50 ohms]-[87.76 ohms]; p = 0.25). These findings suggest that LPs were associated with lower overall complication rates and similar effectiveness to TVPs. However, randomized controlled trials are warranted to validate these results.

A leadless ventricular pacemaker providing atrioventricular synchronous pacing in the real-world setting: 12-Month results from the Micra AV post-approval registry

BackgroundAdvances in leadless pacemaker technology have enabled accelerometer-based atrioventricular (AV) synchronous pacing by sensing atrial mechanical contraction. ObjectiveThe purpose of this study was to report the performance of the Micra AV leadless pacemaker from the worldwide Micra AV post-approval registry (PAR) through 12 months. MethodsThe Micra AV PAR is a prospective, single-arm, observational registry designed to assess the safety and effectiveness of Micra AV in a real-world setting. For the present interim analysis, major complications and system revisions through 12 months were summarized and compared to a historical cohort of 2667 patients implanted with a transvenous dual-chamber pacing system. ResultsThe device was successfully implanted in 796 of 801 patients (99.4%) at 97 centers in 19 countries. Micra AV patients were older (74.1 years vs 71.1 years; P < .0001) with a higher incidence of renal disease (22.3% vs 9.8%; P < .0001) compared with transvenous dual-chamber patients. Through 12 months, the major complication rate was 3.7% in Micra AV patients compared with 8.8% in transvenous dual-chamber patients (hazard ratio 0.42; 95% confidence interval 0.28–0.61; P < .001). The system revision rate was 1.5% in Micra AV patients compared with 5.5% for transvenous dual-chamber patients (hazard ratio 0.25; 95% confidence interval 0.13–0.47; P < .001); this reduction was largely driven by the absence of lead dislodgments requiring revision. The median AV synchrony index was 79.4% (interquartile range 65.2%–86.4%) in patients paced >90%. ConclusionThe Micra AV leadless pacemaker was implanted with a high rate of success in patients with multiple comorbidities, with a significantly lower rate of complications and system revisions through 12 months compared to a historical cohort of patients with transvenous dual-chamber pacemakers.

Single-chamber leadless pacemaker Aveir VR implantation: Pioneer experience in Poland. Insights and preliminary report from a multicenter national registry.

Single-chamber leadless pacemaker Aveir VR implantation: Pioneer experience in Poland. Insights and preliminary report from a multicenter national registry.

Low prevalence of new-onset severe tricuspid regurgitation following leadless pacemaker implantation in a large series of consecutive patients

Low prevalence of new-onset severe tricuspid regurgitation following leadless pacemaker implantation in a large series of consecutive patients

Leadless pacemaker implementation at the right atrial appendage apex: An initial preclinical assessment.

This study evaluates the feasibility and efficacy of implanting a leadless pacemaker at the right atrial appendage (RAA) in a preclinical minipig model, aiming to address the limitations of atrial pacing with current leadless devices like the Medtronic Micra, which is typically used for right ventricular implantation. Four minipigs, each with a median body weight of 45.8±10.0kg, underwent placement of the Micra transcatheter pacing system (TPS) via the right femoral vein into the RAA apex. The pacing performance was assessed over 1-week (short-term) and 3-month (long-term) periods. The initial findings indicated successful implantation, with satisfactory intrinsic R-wave amplitudes and pacing threshold. In the following period, the sensitivity, threshold, and impedance were stable with time. Notably, upon explanation at 3 months, a deep myocardial penetration by the device was observed, necessitating a redesign for safe long-term use in a growing subject's heart. While initial results suggest that RAA apex placement of the Micra TPS is promising for potential inclusion in a dual-chamber pacing system, the issue of myocardial penetration highlights the need for device redesign to ensure safety and effectiveness in long-term applications.

Leadless pacemaker implantation versus conventional transvenous cardiac pacing early after transcatheter aortic valve replacement: a safe and relevant option?

Abstract Background Leadless pacemakers (LPM) are known to have lower postoperative complications than conventional transvenous cardiac pacing especially in frail patients (pts) with many comorbidities. The aim of this study was to assess the "real-life" feasibility and outcomes of LPMs compared to transvenous pacemakers (TPMs) in patients who underwent transcatheter aortic valve replacement (TAVR). Methods This is a retrospective single center study including all consecutive patients who received LPM or TPM (either single or double chamber) implantation early after a TAVR over a one-year period since September 2022 with a follow up period of at least 3 months. Results 71 pts were included (mean age 82,56 ± 7,1 years old). 16 pts underwent LPM implantation (22,5%). Leadless system pacing was preferred in pts with history of active systemic infection 43,8%, complex conventional vascular approach 12,5 %, deterioration of general condition and clinical frailty 18,8% and history of breast cancer in 25 % pts. Mean time between appearance of conductive disorders and pacemaker implantation was longer (2,9± 2,8 vs 1,5 ± 1,3 days; p=0,06) in the LPM group probably due to organizational issues. Procedure duration was significantly shorter in the LPM group (46 ±20,5 vs 69 ± 21,1 min; p = 0,01). There was no statistically significant difference in fluoroscopy time between the 2 groups even though this parameter was longer in the LPM group (6,8 min vs 5,6 min; p = 0,413). Significantly lower thresholds were observed in pts with LPM implantation (0,45 ± 0,33 vs 0,66 ± 0,25 V; p = 0,017) with no statistically significant difference between the 2 groups concerning the per-operative impedance value. Median time from pacemaker implantation to discharge was 3,12 ± 3,26 vs 4,78 ±7,16 days after LPM and TPM implantation respectively (p = 0,195). There were less complications in the LPM group (1,4 % vs 9,9 %; p = 0,471). Complications were: arteriovenous fistula for 1 pt with LPM vs 2 pocket hematomas, 1 pneumothorax, 1 per-operative cardiac arrest and 3 leads dislodgements in pts with TPM. The mortality rate was significantly higher in the LPM group (4,2 % vs 2,8 %; p = 0,038) although no pacemaker related deaths were reported in both groups and no significant difference between the 2 groups was noted concerning rehospitalisations for cardiovascular cause (p= 0,407). Conclusion Early LPM implantation after TAVR is a feasible alternative to conventional pacing with significantly shorter procedure durations and better pacing thresholds. Our experience confirms the global clinical frailty of patients receiving LPM after TAVR but underlines the favorable safety profile of leadless system pacing with a low rate of complications.

Transfemoral leadless pacemaker implantation after tricuspid valve surgery and intervention

Abstract Background and Purpose Pacemaker (PM) implantation after surgical or transcatheter tricuspid valve (TV) repair or replacement may be challenging. Transcatheter leadless pacemaker (LPM) implantation has become a routine procedure and is frequently adopted in patients without the need for an atrial lead, in cases with cardiac implantable device infection or in patients with marked comorbidities. The use of LPM in patients with previous TV repair or replacement has only been described in singular cases in literature. We present our single center experience of LPM implantation after TV repair. Methods Patients with a history of TV repair or replacement who underwent LPM in our institution between 01/2020 and 11/2023 were retrospectively analyzed. All patients underwent routine clinical follow-up investigations including LPM interrogation and transthoracic echocardiography to assess for TV status. For LPM implantation right anterior oblique (RAO) and left anterior oblique (LAO) caudal fluoroscopy projections were utilized to enable LPM device passage across the TV. Results The study population consisted of 10 patients (9 females, mean age 74.0±10.0 years). Two patients had a history of surgical TV annuloplasty repair and two patients a history of surgical valve replacement, four patients of transcatheter TV repair (one through the mitral clip), one patient of transcatheter valve-in-ring bio prosthesis implantation prosthesis after previous surgical ring deployment and one patient transcatheter TV replacement (Figure1). All patients suffered from permanent atrial fibrillation previous to implantation procedures. Three patients were on chronic hemodialysis therapy before LPM implantation. LPM systems were successfully implanted in all cases with a mean procedure time of 43.5±26.5 minutes and a mean fluoroscopy time of 5.9±5.5 minutes and a radiation dose of 1148,7±1424,9 cGy·cm2. For fluoroscopically guided TV crossing a mean LAO angle of 43.6±14.1° (range 22 to 53°) and caudal angle of 8.5±6.9° (range 0 to 20°) was utilized (Figure 2). The LPM device was positioned in the first positioning attempt in a right ventricular high septal localization in 8 cases. Mean pacing threshold was 0.36±0.07 V at 0.25 ms, with a mean sensing amplitude of 10.5±2.9 mV and a mean of 853±324 Ohms pacing impedance. No periprocedural complications occurred. Mean duration of follow-up was 8.1±9.2 months. There were no newly developed TV regurgitations noted. Pacing thresholds (0.37±0.1 V/0.25 ms), sensing amplitude (11.8±4.5 mV) as well as pacing impedances (865±365 Ohms) remained stable until the last follow-up investigation. Conclusion LPM implantation was feasible in patients with a history of TV repair or replacement. LPM implantation was safe and effective in various modalities of TV repair. LPM may be an alternative to conventional pacemaker implantations as well as surgical lead placement in selected patients.Figure 1.Figure 2.

Evaluation of the quality of life of patients with leadless pacing system during 1 year follow-up period

Abstract Background Leadless pacemakers (LesPM) are a new safe alternative technology for pacing the right ventricle. However, not enough information is available on their potential benefits for quality of life (QoL) in patients with LesPM. The purpose of the study was the quality of life comparison of patients with LesPM and conventional pacemakers (ConvPM). Methods The study included patients who underwent implantation of a single-chamber pacemaker from December 2018 to March 2023. We used the SF-36 Questionnaire to assess quality of life at baseline and after 12 and 24 months of follow-up. We also used a questionnaire consisting of 10 specific questions related to the implantation procedure. Results Total of 50 patients were included (25 LesPM; 25 ConvPM). There were no differences in baseline characteristics between groups (LesPM vs. ConvPM), except for age (47.5 vs. 57.3 years; P = 0.012) and diabetes 28% vs. 21%; P = 0.021). Baseline SF-36 did not differ between groups. After 6 months of follow-up, patients in the LesPM group showed significantly higher scores on physical function (47 vs 32; P&amp;lt;0.001), physical role (53 vs 37; P=0.004) and mental health (67 vs 52; P=0.017), even after adjusting for covariates. Pacemaker-related discomfort and physical limitations were significantly lower in the LesPM group. Conclusion LesPM is associated with a better quality of life than ConvPM, both in terms of physical and mental health. Patients who underwent LesPM implantation reported less procedure-related discomfort, physical limitations, and anxiety.

Outcomes of leadless pacemaker in chronic kidney disease patients: real-world data from the i-LEAPER registry

Abstract Background Chronic kidney disease (CKD) represents a major risk factor for patients requiring transvenous pacemaker (TV-PM), resulting in a high rate of operative complications and PM-related infection rate (21.9% and 12.5%, respectively), with both complications parallels to severity of CKD. Moreover, TV leads represent an important concern for end-stage CKD patients, often needing vascular access patency for renal replacement therapy. In this setting leadless pacemakers (LPMs) represent an attractive alternative to TV-PM for their lower device-related infection rate and the absence of TV leads. To date, limited data on LPM safety and efficacy profile in CKD patients are available. Purpose to assess operative and long-term safety and efficacy of LPMs implantation in patients with different stages of CKD in the real-world setting. Methods Consecutive patients who underwent LPM implantation in 12 European centers joining the i-LEAPER registry were retrospectively enrolled. CKD stage was assessed according to CKD-EPI equation for eGFR. Patients with CKD stage G3a/b (N=245) and stage G4/G5 (N=67) were compared with patients with normal kidney function (NKF) (N=867). Primary safety endpoint was LPM-related major complications rate at implant and during follow-up (FU). Additionally, the rate of patients showing sub-optimal electrical performance (pacing threshold [PT] &amp;gt;1V@0.24ms) was compared between groups. Results 1179 patients were enrolled and followed for a median of 33 [IQR 24-47] months. When compared with the NKF group, patients with CKD stage G3a/b and stage G4/G5 showed a higher burden of cardiovascular comorbidities (Table 1). The choice of a LPM was mainly due to vascular concern in the CKD stage G4/G5 group, while a perceived highest infective risk was reported in CKD stage G3a/b group (Table 1). Major complication rate at implant and during FU did not differ between groups, regardless of renal impairment stage (Table 2). All-cause mortality incidence resulted higher in CKD stage G4/G5 group when compared with NKF group (17.9% vs 6.8%; HR 4.24; 95%CI 4.25-7.94, p&amp;lt;0.001) (Figure A). The rate of patients with PT&amp;gt;V1@0.24ms during FU did not differ between groups, not exceeding 13.8%, and therefore remaining consistent with historical data for LPM (Figure B). Conclusion In the real-world setting, LPM showed a remarkable safety and efficacy profile in CKD patients regardless of renal impairment stage that was comparable to NKF population. LPM should be considered as first choice in CKD patients requiring a PM.

Trends in adoption of extravascular cardiac implantable electronic devices: the Dutch cohort

Abstract Introduction Conventional implantable cardioverter-defibrillators (ICDs) and pacemakers carry a risk of mainly pocket- and lead-related complications. To avoid these complications, extravascular devices (EVDs) have been developed, such as the subcutaneous ICD (S-ICD) and leadless pacemaker (LP). However, data on the actual adoption of EVDs for patient or center characteristics is lacking. Purpose To assess real-world nationwide trends in adoption of EVDs in the Netherlands. Methods Using the Netherlands Heart Registration, all consecutive patients with a de novo S-ICD or conventional single-chamber ICD implantation between 2012-2020, or with a de novo LP or conventional single-chamber pacemaker implantation between 2014-2020 were included. Trends in adoption of EVDs are described for different patient and hospital characteristics (tertiles of device-implanting volume and whether cardiothoracic surgery back-up was available). Differences between patients with EVDs and non-EVDs and differences between implanting centers of EVDs and non-EVDs were tested for by Student’s T-test, Chi-square and Fisher’s exact test. Trends in adoption over time were calculated with linear and logistic regression analysis. Results From 2012-2020, 2190 S-ICDs and 10683 conventional ICDs were implanted; from 2014-2020, 712 LPs and 11103 conventional pacemakers were implanted. The general adoption of both increased (S-ICDs, 8% to 21%; LPs, 1% to 8%), but the increase seems to reach a plateau (Fig. 1). S-ICD recipients were younger than conventional ICD recipients (p&amp;lt;0.001) and more likely to be female (p&amp;lt;0.001); LP recipients were younger than conventional pacemaker recipients (p&amp;lt;0.001) and more likely to be male (p=0.03). Both S-ICDs and LPs were mainly implanted in high-volume centers with thoracic surgery on-site (Fig. 2). Conclusions In this nationwide study we observed a relative quick adoption of innovative EVDs with a plateau after approximately 4 years. The relative adoption of S-ICDs is especially high in younger patients. EVDs are overall mainly implanted in high-volume centers with cardiothoracic surgery available. As LPs can only be implanted in centers with cardiothoracic surgery in the Netherlands, this may have limited its adoption.

Impact of comorbidities on survival and complications in patients implanted with leadless pacemakers: a national, multicenter study

Abstract Background The number of leadless cardiac pacemaker (LCP) implantations has increased over the recent years, being more frequently performed in elderly patients with multiple comorbidities. Purpose The aim of this study is to analyze periprocedural complications and outcome of LCP patients according to their comorbidity status. Methods This is a Swiss multi-centre, retrospective cohort study including all consecutive patients implanted with a LCP (Medtronic Micra VR or AV) between 2015 and 2022. Charlson Comorbidity Index (CCI) was determined and patients were divided into two groups: CCI ≤ 5 (low comorbidity) and CCI &amp;gt; 5 (high comorbidity). Periprocedural complications, in-hospital death, and all-cause mortality were assessed. Results A total of 863 patients (median age 81 years (IQR 76 – 86), male sex 65%) were included in the study, of which 58% had a CCI ≤ 5. Baseline characteristics of the 2 groups are summarized in the table. Patients in the high comorbidity group were older male presenting more frequently with ischemic cardiomyopathy, diabetes, chronic obstructive pulmonary disease, moderate to severe chronic kidney disease and malignancies. Urgent implantations were more frequent in the high comorbidity than in the low comorbidity group (65% vs. 50%, p&amp;lt;0.001). Overall periprocedural complication rate was 2.9% (n = 25) without significant differences between the two groups (2.9% in both groups, p = 1.0). Pericardial effusion requiring pericardiocentesis was the most frequent periprocedural complication (n = 8, 0.9%). Median hospitalization was significantly longer (5 vs. 3 days, p&amp;lt;0.001), and in-hospital mortality significantly higher (3.6% vs. 0.6%, p=0.002) in the high comorbidity group. None of the in-hospital deaths was deemed a periprocedural complication. Median follow-up was 15.4 months. As shown in the figure, all-cause mortality was significantly higher in the high morbidity group (HR 2.9, 95%-CI 2.2-3.8, p&amp;lt;0.001) resulting in a mortality of 58% at 3 years. Conclusions LCP implantation in patients with multiple comorbidities was equally safe with similar peri-procedural complication rates as compared to patients with less comorbidities. However, both in-hospital death and all-cause mortality during follow-up were significantly higher in the high comorbidity group, because patients were older and sicker. Given that costs of LCPs are substantially higher than standard transvenous pacemakers, further studies are necessary to assess cost-effectiveness in patients with high comorbidity and reduced life expectancy.Figure - Survival estimate according CCITable - Baseline characteristics

Leadless pacemaker implantation following tricuspid interventions: multicenter collaboration of feasibility and safety

Abstract Background Permanent pacing is often required following valve intervention (either surgical or percutaneous), however tricuspid interventions pose specific challenges to conventional pacing. Therefore, leadless pacemaker (LP) implantation may be the preferred strategy when permanent pacing is required after tricuspid valve intervention. Objective To report periprocedural outcomes and follow-up of patients undergoing implantation of a LP system following tricuspid valve interventions. Methods Consecutive patients with previous tricuspid valve intervention at the time of attempted implantation of a LP were included. Results Between 2019 and 2022, 40 patients underwent LP implantations following tricuspid interventions in 5 large tertiary centers. The mean age was 68.9 ± 13.7 years, and 48 % patients were male. The indication for pacing was as following: AVB in 27 (68%) patients, AF with slow ventricular response in 10 (25%) patients, and refractory rapid atrial fibrillation (AF) referred to AV junction ablation in 3 (7%) patients. Most of the patients received Micra VR (78 %). Procedure was successful in all patients. Mean procedural time of 58 ± 32 min and median fluoroscopy time of 7.5 min. Electrical parameters were within normal range (threshold: 1.35 ± 1.2 V@0.24 ms, impedance: 772 ± 245 Ohm, R-wave: 6.9 ± 5.4 mV). No acute complications were observed. During a mean follow-up of 10 months, electrical parameters remained stable, and 4 deaths were occurred (not related to the procedure). Conclusion A LP is safe and efficient option following tricuspid valve interventions.Micra LP in a patient with bioprostheticMicra LP in a patient with tricuspid rin

Upgrading a single-chamber leadless pacemaker to a dual-chamber leadless pacemaker system

Abstract Background/Introduction The first global dual-chamber leadless pacemaker (DR-LP) study included a group of subjects with a pre-existing upgradeable ventricular single chamber leadless pacemaker (VR-LP) in whom the addition of an atrial leadless pacemaker (AR-LP) was undertaken to allow upgrading to a dual chamber leadless pacing (DR-LP) system. Purpose Summarize success rates of single to dual chamber leadless pacemaker upgrades, as well as device and i2i throughput measurements, serious adverse device effects (SADEs) and mortality in this cohort. Methods Subjects with a pre-existing VR-LP who were indicated for a dual-chamber pacemaker were included. Upgrade procedures included downloading firmware to existing VR-LP, placing AR-LP, and pairing the devices to operate in a DR-LP mode. Electrical and i2i throughput measurements were collected at implant, pre-discharge, 1-mo, 3-mo, 6-mo, and 12-mo. Upgrade success rate was defined as an AR-LP upgrade procedure that resulted in a functional DR-LP system. SADEs included all reported events that were adjudicated as serious and possibly, probably or causally related to the procedure or system. SADEs and deaths were adjudicated by an independent clinical events committee. Results Out of 36 enrolled subjects (61.1% male, 70.4 ± 13.8 yrs., 55.6% sinus node dysfunction, 38.9% AV block), 35 had an attempted implant, and 32 of these were successful (91.4%). The 3 unsuccessful upgrade attempts were related to unsuccessful placement of the AR-LP due to complications during the procedure (n = 2) or an inability to implant an AR-LP (n = 1). Figure 1 illustrates a declining early mean pacing capture threshold, rising early P-wave amplitudes, and stable impedance for the AR-LP over the 12 months. Mean i2i throughput for communication from the RV to RA and the RA to RV improved from pre-discharge to 3 months and remained stable through the subsequent 9 months (Figure 2). A total of 5 subjects (5 of 36; 13.9%) experienced 7 SADEs (all procedure-related; 2 related to the AR-LP and 2 to the delivery catheter). One non-cardiovascular, non-device, non-procedure related death occurred in the upgrade population. Conclusions The single to dual-chamber upgrade cohort demonstrated a high upgrade success rate (91.4%), stable atrial and ventricular electrical measurements and consistently high i2i communication throughout the 12 months. AV synchrony (AVS) was not specifically measured in this upgrade cohort, but data from the main DR-LP study suggest that i2i throughput correlates with, but significantly underestimates AVS. Further, the rate of complications was acceptable (13.9%) and limited to the procedure. These data confirm the feasibility, safety and longer-term effectiveness of adding an atrial LP in patients with a pre-existing ventricular LP order to achieve effective dual chamber pacing.Fig. 1: Upgrade Electrical measurementsFig. 2: i2i communication for Upgrades

Electrocardiogram predictors of leadless pacemaker implantation in the right ventricular free wall

Abstract Background Leadless pacemakers (LLP) carry the potential risk of cardiac injury, especially when implanted in the free wall of the right ventricle. Purpose To investigate the ECG criteria for distinguishing free wall implantation of LLP, further clarification is needed. Methods We conducted a retrospective study involving 17 patients who underwent LLP implantation, followed by chest computed tomography to confirm the implantation site. Patients were categorized into three groups based on the location of implantation (septum [Sep], apex [Apex], and free wall [FW]), and we compared the morphology of the 12-lead ECG during LLP pacing. Results Among the implantation sites, nine were in the Sep (52.9%), five in the Apex (29.4%), and three in the FW (15.8%). In terms of pacing QRS morphology, the FW group exhibited significantly longer QRS duration (Sep: 145.6±15.2 vs. Apex: 161.6±3.6 vs. FW: 175.3±16.6, P&amp;lt;0.01), a notched QRS complex in lead III (Sep: 0.0% vs. Apex: 0.0% vs. FW: 100.0%, P&amp;lt;0.01), and a shorter peak deflection index (PDI) in lead V1 (Sep: 0.59±0.07 vs. Apex: 0.55±0.06 vs. FW: 0.40±0.02, P&amp;lt;0.01) than the other two groups. Receiver operating curve analysis to predict FW implantation revealed that a PDI of 0.42 in lead V1 (Area under the curve [AUC]=1.00, specificity=100.0%, sensitivity=100.0%, P&amp;lt;0.01) and a QRS duration of 173 msec (AUC=0.89, specificity=100%, sensitivity=66.7%, P&amp;lt;0.01) were the optimal cutoff values. Conclusion The LLP FW implantation group had a longer QRS duration, a notched QRS complex in lead III, and a shorter PDI in lead V1 compared to the other pacing sites.

Leadless pacemaker implantation via the internal jugular vein a promising access for an established intervention

Abstract Background Leadless pacemaker therapy was introduced in 2013 to overcome lead- and pocket-related complications in conventional transvenous pacemaker therapy. These leadless devices are self-contained right ventricular single-chamber pacemakers implanted via a femoral percutaneous approach. However, the femoral route is not always possible due to various reasons. The aim of this analysis is to share our first experience using a jugulary approach for the implantation procedure. Purpose To evaluate safety and feasibility of leadless pacemaker implantation via the internal jugulary vein. Methods The records of the first 34 patients who underwent leadless pacemaker implantation via the right internal jugular venous route at our center were analyzed prospectively. Follow-up period was 3 months. Safety as well as efficacy including electrical parameters of the jugular approach were compared with the data of the first 100 patients who underwent a femoral leadless pacemaker implantation at our center (implanted from 2015-2019). Results Thirty-four patients underwent internal jugular vein leadless pacemaker implantation (mean age, 82.37 ± 7.58, 58.8% males). All leadless pacemakers were implanted successfully. The jugular approach was well tolerated by all patients. Mean procedure time was 33.29 ± 8.81 min with a mean fluoroscopy time of 3.66 ± 2.07 min. The device was positioned at the inferior septum in 11 patients, at the high septum in two and midseptal in 21 patients. The mean pacing threshold was 0.52 ± 0.22 V at 0.24 ms pulse width with a sensed amplitude of 9.13 ± 4.08 mV. There were no complications during the procedure as well as during 3-month follow-up. At follow-up, electrical parameters remained stable in all patients. Conclusion Implantation of a leadless pacemaker via the right internal jugulary vein is a safe and effective alternative to the femoral approach.Patient demographics/device parameterDevice value development over time.

The pacing threshold improvement of leadless pacemaker is better when mid or high right ventricular septal (RVS) approach than lower RVS approach after follow-up of 3 months

Abstract Introduction Leadless pacemaker procedures are rapidly increasing in last decade. Compared to conventional trans-venous pacemaker, pacing threshold of leadless pacemaker is important parameter for longevity (reference 1.). For the safety, right ventricular septum (RVS) is recommended as the pacing location. Recent study (reference 2.) showed that pacing thresholds in most leadless pacemaker implantation patients with elevated thresholds decrease after implant. Therefore, leadless pacemaker repositioning may not be necessary if the pacing threshold is ≤2 V. However, according to pacing location with mid-or above septum versus low or apical septum, pacing threshold stability and improvement during follow-up period after implantation is not clear. Method 68 cases of leadless pacemaker implantation in 2 hospitals with 3 physicians was analysed. According to pacing location, we divided 2 groups with mid or above RVS and lower RVS. Patients with pacing location on mid or above RVS was 27 (Group A). Other patients with pacing location on lower RVS was 41 (Group B). During follow-up (mean 6 months), we analysed pacing threshold and QRS duration on electrocardiography (ECG) after implantation. Results Table 1. shows baseline characteristics including age, sex, and comorbidity were not different significantly between 2 groups. Only HF is lower in group A (14.8% versus 36.6%, p=0.044). Table 2. shows the comparison of 2 groups. Initial threshold of lower RV septal approach (Group B, 0.39±0.14V/0.24ms) showed better than mid or high septal approach (Group A, 0.70±0.33V/0.24ms), p &amp;lt;0.001. However, 3 months later, pacing threshold decreased lower in Group A (mid or above RVS, 0.49±0.17V/0.50ms) than Group B (lower RVS, 0.67±0.50V/0.24ms), p &amp;lt;0.001. Therefore, the change of pacing threshold is improved in Group A (mid or above RVS, -0.20±0.24V/0.24ms) than Group B (lower RVS, 0.28±0.51V/0.24ms), p &amp;lt;0.001. However, other parameters including QRS duration and LVEF after implantation was not different between 2 groups. Conclusion The improvement of pacing threshold in mid or high RVS approach demonstrates that pacing threshold stability is more dominant than lower RVS approach. Our data shows that, after follow-up of 3 months, pacing threshold improvement of leadless pacemaker after implantation is better when mid or high RVS approach than lower RVS approach.Figure 1.Table 1. and 2.