Transcatheter Pacing System Research Articles

Novel parameters for micra transcatheter pacing system implantation on the right ventricular mid-septum

Abstract Background No procedural parameters for Micra transcatheter pacing system (Micra TPS) implantation on the right ventricular mid-septum have been established though it is encouraged for safety. Purpose We aimed to investigate procedural predictors for Micra TPS implantation on the ventricular mid-septum. Methods This is a single-center, retrospective and observational study. Eighty-two patients who underwent Micra TPS implantation were enrolled. The implantation sites of the ventricular septum were classified into basal, mid and apical-septum in the right anterior oblique 35° image. Predictors for mid-septal implantation were evaluated using univariable and multivariable logistic regression analysis which involved explanatory variables considered clinically important. The explanatory variables included the angle between the axis of a device cup of a delivery catheter and the tangent of the ventricular septum in the left anterior oblique 45° image (defined as angle θ). The diagnostic cut-off value of the significant predictor for mid-septal Micra implantation was assessed using receiver operating characteristic (ROC) curve analysis. Results Micra TPS was implanted on the ventricular mid-septum in 61 patients (74.4%), the apical-septum in 21 patients (25.6%), and the basal-septum in no patients. In univariable logistic regression analysis, each angle θ and α-loop shape appearance of a delivery catheter was significantly associated with mid-septal implantation (Odds ratio [OR], 1.1; 95% confidential interval [CI], 1.02-1.10; P=0.002, and OR, 4.6; 95% CI, 1.63-13.6; P=0.005, respectively). After multivariable adjustment, both angle θ and α-loop shape appearance were independently associated with mid-septal implantation (adjusted OR, 1.1; 95% CI, 1.01-1.09; P=0.010, and adjusted OR, 3.3; 95% CI, 1.01-11.4; P=0.048, respectively). Because no Micra TPS was implanted on the basal-septum, an ROC curve for binary outcome of mid-septal and apical-septal implantation was drawn. The ROC curve showed a cut-off value of angle θ for Micra TPS implantation on the ventricular mid-septum was 22° with high sensitivity and specificity at 80.0% and 70.0% (area under the curve= 0.781). Conclusion The angle θ ≧ 22°and the α-loop shape appearance of a delivery catheter may be useful predictors for Micra TPS implantation on the ventricular mid-septum.

Transcatheter non-acute retrieval of the tine-based leadless ventricular pacemaker.

We report our single-centre experience of mid-term to long-term retrieval and reimplantation of a tine-based leadless pacemaker [Micra transcatheter pacing system (TPS)]. The TPS is a clinically effective alternative to transvenous single-chamber ventricular pacemakers. Whereas it is currently recommended to abandon the TPS at the end of device life, catheter-based retrieval may be favourable in specific scenarios. We report on nine consecutive patients with the implanted TPS who subsequently underwent transcatheter retrieval attempts. The retrieval system consists of the original TPS delivery catheter and an off-the-shelf single-loop 7 mm snare. The procedure was guided by fluoroscopy and intracardiac echocardiography. After an implantation duration of 3.1 ± 2.8 years (range 0.4-9.0), the overall retrieval success rate was 88.9% (8 of 9 patients). The mean procedure time was 89 ± 16 min, and the fluoroscopy time was 18.0 ± 6.6 min. No procedure-related adverse device events occurred. In the one unsuccessful retrieval, intracardiac echocardiography revealed that the TPS was partially embedded in the ventricular tissue surrounding the leadless pacemaker body in the right ventricle. After retrieval, three patients were reimplanted with a new TPS device. All implantations were successful without complications. A series of transvenous late retrievals of implanted TPS devices demonstrated safety and feasibility, followed by elective replacement with a new leadless pacing device or conventional transvenous pacing system. This provides a viable end-of-life management alternative to simple abandonment of this leadless pacemaker.

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.

TIMES, ARE THEY A–CHANGING? IMPLANTATION AND FOLLOW–UP EXPERIENCE WITH LEADLESS PACEMAKERS (MICRA) AT PISA UNIVERSITY HOSPITAL

Abstract Background Leadless pacing represents a pivotal advancement in cardiac stimulation. Eliminating traditional pacing leads, leadless devices offer reduced complications, a bailout strategy for many previously challenging cases and streamlined procedures. Purpose This retrospective study aimed to compare, starting from December 1st 2023, newer implants (within the 3 years preceding Dec 1st 2023) and older implants (>3 years before) in a single–center experience with M–TPS (Micra Transcatheter Pacing System) in terms of safety and efficacy, at baseline and in a short–term follow–up (6 months). Methods A comprehensive analysis was conducted on 195 patients who underwent leadless pacemaker implantation at our Center, and that were followed–up for a minimum of 6 months. The cohort was stratified into two groups: recent (n=73) and less recent implants (n=122). Procedural variables, patient demographics, and clinical outcomes were documented. Post–implantation follow–up data include pacing threshold, fluoroscopy time, and other relevant variables. Results Comparison between the two groups revealed significant differences fluoroscopy time. Newer implants demonstrated a reduced fluoroscopy time [8 (IQR 5–12) vs 10 minutes (IQR 7–14)], suggesting potential advancements in technique. No significant differences were observed in other procedural or electrical parameters. Discussion: The comparison between older and newer leadless pacemaker implants reveals reassuring constancy in most parameters, suggesting the reliability of the M–TPS. The reduced fluoroscopy time aligns with the evolving proficiency of implanters and improved procedural efficiency. The dependable consistency observed across various parameters strengthens the confidence in the M–TPS, reinforcing its status as a reliable and effective solution for pacing. Conclusion The implantation and follow–up experience at our center elucidates very few differences between newer and older implants. This nuanced analysis contributes to the ongoing evolution of leadless pacemaker technology, which heralds a transformative era in cardiac care. With several years of implementation, accumulated follow–up data unveils valuable insights into its sustained effectiveness, guiding clinicians in optimizing patient outcomes and solidifying leadless pacing as a breakthrough in the realm of cardiac rhythm management.

Leadless pacemakers at 5-year follow-up: the Micra transcatheter pacing system post-approval registry.

Prior reports have demonstrated a favourable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. Updated performance of the Micra VR leadless pacemaker through five years from the worldwide post-approval registry (PAR) was assessed. All Micra PAR patients undergoing implant attempts were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 transvenous pacemaker patients using Fine-Gray competing risk models. 1809 patients were enrolled between July 2015 and March 2018 and underwent implant attempts from 179 centres in 23 countries with a median follow-up period of 51.1 months (IQR: 21.6-64.2). The major complication rate at 60 months was 4.5% [95% confidence interval (CI): 3.6%-5.5%] and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: .47, 95% CI: .36-.61; P < .001). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%-6.1%). System revisions among Micra patients were mostly for device upgrades (41.2%) or elevated thresholds (30.6%). There were no Micra removals due to infection noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.2% vs. 6.6%, P < .001). Long-term outcomes with the Micra leadless pacemaker continue to demonstrate low rates of major complications and system revisions and an extremely low incidence of infection.

MICRA AV implantation after transcatheter aortic valve replacement

BackgroundTranscatheter aortic valve replacement (TAVR) has evolved as a breakthrough therapy for patients with severe aortic valve stenosis. While TAVR has revolutionized the management of aortic valve disease, the procedure may be associated with the development of conduction disturbances requiring permanent pacemaker implantation. Traditionally, conventional transvenous pacemakers have been used to address these complications. However, the introduction of leadless pacemaker technology, such as the MICRA Transcatheter Pacing System (TPS), offers a novel alternative. Materials and methodsThis was a retrospective single-center study where all patients who underwent TAVR at our center and subsequently required permanent pacemaker implantation within 30 days were reviewed. We included only the patients who underwent leadless pacemaker placement. We then conducted a retrospective chart review to identify patient and procedural characteristics, procedural details, and relevant clinical outcomes. ResultsA total of 9 patients were identified. All of the patients underwent MICRA AV placement within 30 days post-TAVR by an interventional cardiologist. The average age of the cohort was 79.6 years with an average STS score of 3.7 %. The majority of the patients received balloon-expandable valves (78 %). There were no procedural complications in any of the patients. At an average follow-up of 353 days, capture thresholds and lead impedance remained stable with an average RV pacing of 13 %. ConclusionThis small, retrospective cohort demonstrates that the use of MICRA AV leadless pacemakers is feasible after TAVR and is associated with low periprocedural complications. Leadless pacemakers provide stable pacing thresholds and AV synchrony.

The Micra Transcatheter Pacing System: past, present and the future.

Leadless permanent pacemakers represent an important innovation in cardiac device developments. Althoughtransvenous permanent pacemakers have become indispensable in managing bradyarrhythmia and saving numerous lives, the use of transvenous systems comes with notable risks tied to intravascular leads and subcutaneous pockets. This drawback has spurred the creation of leadless cardiac pacemakers. Within this analysis, we compile existing clinical literature and proceed to evaluate the efficacy and safety of the Micra Transcatheter Pacing System. We also delve into the protocols for addressing a malfunctioning or end-of-life Micra as well as device extraction. Lastly, we explore prospects in this domain, such as the emergence of entirely leadless cardiac resynchronization therapy-defibrillator devices.

PP41 Using Medicare Claims Data To Support Reimbursement Of A Novel Leadless Pacing System For The Management Of Bradycardia

IntroductionThe Micra Transcatheter Pacing System (Micra TPS) is a single-chamber transcatheter leadless pacemaker (LPM). LPMs do not require leads or a subcutaneous pocket, which represent the primary sources of device-related complications with conventional transvenous pacemakers (TVPMs). Complications such as infections and lead dislodgements cause significant patient burden, which have significant economic consequences. Running a randomized controlled trial (RCT) to estimate risk differences of infrequent events requires large sample sizes and long follow-up periods. Real-world observational data, while informative, requires an appropriate study design and statistical adjustments to control for potential biases.MethodsThe Micra Coverage with Evidence Development (CED) study was a cohort study of LPM versus TVPM based on US Medicare claims data of 16,431 patients with 2-year follow up (LPM: n=6,219; TVPM: n=10,212). Propensity score matching (PSM) was applied to account for differences in baseline characteristics. As no RCT was identified in the literature, this study was presented to the Australian payer as the primary source of clinical evidence, upon which a cost-utility analysis was conducted.ResultsAfter PSM, the CED study demonstrated significantly more complications with TVPM versus LPM with adjusted rates of 6.5 percent and 4.6 percent (p&lt;0.001). Significant differences favoring LPM (p&lt;0.01) were observed in device breakdown (1.4% vs 2.0%), dislodgment (0.4% vs 1.2%) and infection (&lt;0.1% vs 0.6%). Based on these findings, a claim of superior safety was accepted by Medical Services Advisory Committee (MSAC) to support reimbursement. In making this decision, MSAC considered that the large sample size and propensity weighting overcame some of the potential biases and the magnitude of the benefit supported cost-effectiveness relative to TVPM.ConclusionsThe lack of a sufficiently powered RCT with an extended follow-up period can mean the impact and benefits of new technologies that reduce clinically important adverse events of relative infrequency are not formally incorporated into payer decision making, particularly where RCTs are a requirement. A well-designed observational study can provide valuable, real-world evidence to support a HTA for reimbursement decisions.

Acute pacing threshold elevation during simultaneous Micra leadless pacemaker implantation and AV node ablation: Clinical cases, computer model and practical recommendations.

In patients with refractory atrial fibrillation (AF), atrioventricular nodal (AVN) ablation and permanent pacemaker implantation is recommended. The Micra Transcatheter Pacing System (Micra) is a single chamber leadless pacemaker (LPM) and thus offers the possibility of AV node (AVN) ablation in the same procedure. Pacing threshold (PT) elevation after radiofrequency (RF) ablation is a potential complication. We conducted a single center retrospective cohort study. Patients implanted with a Micra (n = 84) and concomitant or delayed AVN ablation (n = 12) from 2014 to 2022 were included. Two cases of acute Micra PT elevation immediately following RF AVN ablation required device retrieval and implantation of a new Micra. Procedural characteristics and electrophysiological parameters were analyzed, and a computer model was performed to determine factors responsible for acute PT elevations. A total of 84 patients were included. Mean age was 74±10 and 48% were women. Twelve patients (14%) underwent AVN ablation. Two patients had acute PT elevation requiring device retrieval despite no direct contact of the ablation catheter with the Micra. Computer modeling shows that significant dissipated power due to electrical field coupling can occur at the tip or ring electrode if the catheter is not kept at a safe distance (≥35mm) from the Micra when a maximum power of 100W is delivered. Concurrent AVN ablation and Micra implantation is safe in most patients. To prevent acute PT elevation, keeping a safe distance of ≥35mm from the tip and ring electrodes of the Micra and using lower power output may prevent this complication.

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

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

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

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). We sought to compare VR and AV systems in sinus rhythm patients with chronic ventricular pacing (Vp) for complete atrioventricular block. 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. 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). 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.

Implantation of a leadless pacemaker as a promising solution for patients with arythmia – current state of knowledge

Introduction: In cardiac electrotherapy, new solutions are constantly sought to minimise the invasiveness of methods used so far and reduce the risk of complications. Implantation of traditional cardiac pacemakers carries risks of high probability that may cause both early and late adverse effects which are associated with presence of subcutaneous lodge and intravenous wires. A significant reduction in complications may be achieved by using leadless pacemakers the main representative of which is MicraTM (MicraTM transcatheter pacing system: TPS, Medtronic plc, Mounds View, MN, USA). Micra is 90% smaller than conventional pacemaker. The generator and electrode system is contained in one capsule-like device that is implanted directly into the right ventricle of the heart. The transcatheter pacing system is less invasive because it is placed in the heart with the use of a catheter via a femoral vein. thus no chest incision and scar. Purpose of the work: The aim is to present the subject of leadless cardiac pacing with the use of Micra device based on a review of current scientific publications. Methods and materials: The available medical literature related to cardiac pacing was analysed taking leadless technology into account. The analysed material was obtained from PubMed and Google Scholar. Conclusion: Cardiac electrotherapy with the use of leadless Micra pacemaker is a great example of substantial technological progress. Due to its structure and form, it is a beneficial alternative to a traditional pacemaker. It also offers promising solutions for the future. This is, however, a relatively new method of stimulation requiring further observation and analysis.

Transcatheter pacing system implant: is it a matter of gender?

Abstract Funding Acknowledgements Type of funding sources: None. Background the leadless pacing system, like Micra Transcatheter Pacing System (M-TPS) is precisely designed to reduce peri- and post-procedural complications, like pneumothorax, lead dislodgement, infections, and lead fracture.Previous studies have already demonstrated its good safety profile and the excellent electrical performance during the follow up. The study aimed to investigate feasibility and long-term electrical outcomes of M-TPS implant and estimate sex differences in leadless pacing. Methods All patients undergone M-TPS implantation in our Institution from May 2014 to October 2022 were included. All patients fulfilled standard criteria for VVI or VDD pacing according to guidelines. Device FU was scheduled at discharge, after 1 month and then every 6 months. Electrical performance was checked. Major complications were defined as life-threatening events, requiring surgical intervention or significant hemodynamic instability or resulting in death. Study population was divided between genders in order to analyze potential differences during the FU Results One hundred ninety-three consecutive patients [148 males, 76.7%, mean age 79 (IQR 73-84) y] were enrolled in this study. Indications for pacing were permanent AF with bradycardia in 107 (55.5%) patients, complete AV block in 59 (30.5%) patients, symptomatic sinus node dysfunction in 20 (10%) patients, and advanced AV block or bifascicular bock in 7 (4%). One hundred seventy-seven patients received VVI pacing, while 16 VDD. There were no statistically significant differences between groups for demographics characteristics (mean age at implant 79 vs 81, p=0.12), except gender. The mean was FU 12 (IQR 1-36) months, maximum 8 years. The implant procedure was successful in all patients and no complications were recorded. We observed no differences between groups in procedure duration [40 (IQR 30-60) min vs 40 (IQR 29-50), p=0.64], fluoroscopy time [9 (6-14) min vs 9 (7-11), p=0.81] and single device delivery (65.7% vs 65.9%, p=0.34). Electrical performance, except for pacing threshold at implantation [0.5 (IQR 0.38-0.75) V/0.24ms vs 0.38 (IQR 0.25-0.63) V/0.24ms, p=0.02), was similar between groups at discharge [pacing threshold 0.38 (IQR 0.38-0.63) V/0.24 ms vs 0.38 (IQR 0.25-0.55) V/0.24 ms, p=0.30; impedance 650 (IQR 560-760) Ohm vs 675 (IQR 580-780) Ohm, p=0.71; R wave amplitude 10.1 (IQR 7-16.2)mV vs 9.5 (IQR 7-14.45) mV, p=0.71] and during the FU [pacing threshold 0.5 (IQR 0.38-0.63) V/0.24 ms vs 0.5 (IQR 0.38-0.5) V/0.24 ms, p=0.11; impedance 570 (IQR 490-630) Ohm vs 580 (IQR 510-640) Ohm, p=0.46; R wave amplitude 11.5 (IQR 7.8-15.7)mV vs 12.7 (IQR 9-18) mV, p=0.26]. Conclusion Leadless pacing therapy is a feasible and safe alternative to conventional pacemakers with similar electrical performance and outcomes during a long-term FU. No differences were found between genders making it a good option especially in women who are often considered fragile in surgical procedure.

Leadless pacing in the elderly: exit strategy or valid alternative?

Abstract Funding Acknowledgements Type of funding sources: None. Background The need for cardiac pacing progressively increases with age and the elderly constitute a special subset of patients, being often very fragile and at a greater risk for procedural complications. Leadless pacing systems appear to be a safe and effective option, being devoid of most complications associated with traditional transvenous pacing systems. Purpose This study aimed to analyze a single-center experience with M-TPS (Micra Transcatheter Pacing System) implantation in terms of safety and efficacy in a long-term follow-up. Methods Between May 2014 and November 2022, 193 patients underwent M-TPS implantation in our Center, all patients fulfilled standard criteria for pacemaker implantation with indication to receive either VVI or VDD pacing. We divided the study population into two groups according to age (group 1 &amp;lt; 79 y vs group 2 &amp;gt;= 80 y) and analyzed procedural outcomes, electrical performance of the system at follow-up (FU), rate of procedural major complications and of device-related events at FU. Results In 95/193 cases (69 males, 73%) M-TPS was implanted in patients &amp;gt; 80 y. There were no statistically significant differences between groups in baseline characteristics. Implant procedure was successful in all cases and no device-related events were registered during FU. Patients were followed-up for an average of 18 months, up to 7 years. No differences were observed between groups in procedure duration, single device delivery (group 1 vs group 2: 62.1 vs 69.6%, p=0.17), fluoroscopy time [10 (IQR 6-14) vs 8.5 (IQR 6-12.5) minutes, p=0.27], electrical performance at implant: pacing threshold [0.44 (0.38-0.63) vs 0.5 (0.38-0.75) V/0.24 ms, p=0.39]; impedance [710 (610-840) vs 700 (600-810) Ohm, p=0.56]; R wave amplitude [9.3 (6 -13.5) vs 8.2 (6 -11.9) mV, p=0.68] and at 6 months follow-up : pacing threshold [0.5 (0.38-0.5) vs 0.38 (0.38-0.5) V/0.24 ms, p=0.25]; impedance [580 (500-640) vs 570 (530-680) Ohm, p=0.38]; R wave amplitude [13.2 (9.5-17) vs 9.7 (7.8-16.7) mV, p=0.17]. The only statistically significant difference was found in the percentage of ventricular pacing (Vp%), which was higher in group 2 [5.3 (IQR 0.5-35) vs 38% (IQR 14-83), p=0.001] and stayed higher at a 12 months follow-up [11 (1-53) vs 60% (10-94)], p=0.001). High pacing threshold (&amp;gt;= 1mV@0.24ms) at implant was present in thirty-one patients (14 vs 19%, p=0.43). Conclusions As the population ages the incidence of rhythm disturbances raises, increasing the need for cardiac pacing. It is imperative to find a therapeutic solution that suits the elderly offering them high efficacy and a low rate of complications. MTP-S implant is an effective and safe procedure in elderly patients with similar electrical performance and outcomes compared with younger patients at long-term follow-up. While initially thought for patients that could not undergo traditional pacing interventions, MTP-S is now emerging as a valid substitute.

Feasibility and outcomes of Micra implant after cardiac implantable electronic device extraction

Abstract Funding Acknowledgements Type of funding sources: None. Background The specific and well-known design features of leadless pacing system (Micra Transcatheter Pacing System, M-TPS) have suggested his use in patients that previously underwent transvenous lead extraction (TLE) for any reason. The study aimed to investigate feasibility and long-term outcomes of M-TPS implant in patients underwent TLE. Methods Patients undergone M-TPS implantation in our Institution from May 2014 to September 2022 were included in the study. All patients fulfilled standard criteria for PM implantation (VVI or VDD mode). Follow-up (FU) was scheduled at discharge, after 1 month and every 6 months thereafter and electrical parameters were checked. Major complications were defined as life-threatening events, requiring surgical intervention or any event causing significant hemodynamic instability or resulting in death. Study population was divided between "naïve pacing" and "post-extraction" patients. Results We enrolled 193 patients (76.7% males), 57 (29.5%) received M-TPS implantation after TLE, needed because of infection in 91.4% of cases. Indications for pacing were permanent AF with bradycardia in 107 (55.5%) patients, complete AVB in 59 (30.5%), symptomatic sinus node dysfunction in 20 (10%), and advanced AVB or bifascicular bock in 7 (4%). There were no statistically significant differences between groups for demographics characteristics and primary PM implant indications, except mean age at implant that was significantly inferior in the post-extraction group [80 (IQR 75-84) vs 78 (IQR 72-83), p=0.04]. Implant procedure was successful in all and no complications were recorded. No differences between groups in procedure duration [40 (IQR 30-50) vs 45 (30-65) min, p=0.34], fluoroscopy time [9 (6-14) vs 9 (6-11) min, p=0.31] and single device delivery (64.9% vs 67.9%, p=0.35) were observed. The mean FU was 12 (1-36) months, maximum 8 years. Pacing variables at implantation [pacing threshold 0.5 (0.38-0.63) vs 0.5 (0.38-0.88) V/0.24 ms, p=0.15; impedance 720 (600-837) vs 675 (615-825) Ohm, p=0.51; R wave amplitude 9 (6.25-12.87) vs 8.2 (5.65-12) mV, p=0.47], discharge [pacing threshold 0.38 (0.38-0.63) vs 0.38 (0.38-0.63) V/0.24 ms, p=0.27; impedance 685 (580-770) vs 610 (560-750) Ohm, p=0.16; R wave amplitude 10.25 (7.2-14.5) vs 9.3 (6.5-16.5) mV, p=0.6], and at 6 months [pacing threshold 0.5 (0.38-0.5) vs 0.5 (0.38-1.25) V/0.24 ms, p=0.64; impedance 580 (520-680) vs 570 (510-640) Ohm, p=0.63; R wave amplitude 11.9 (8.2-16.4) vs 11.7 (9-20) mV, p=0.68; battery voltage 3.09 (3.05-3.11) vs 3.09 (3.04-3.13) V, p=0.71] did not show differences. Conclusion M-TPS is an efficacious and safe alternative to conventional PM, with the main advantage of the absence of transvenous leads and a surgically created subcutaneous pocket, avoiding all the related complications. These devices are a reliable alternative after TLE, with similar electrical performances than those observed in patients who did not previously received pacing.

Comparison of 1st and 2nd generation leadless pacemaker in sinus rhythm patients with chronic ventricular pacing for complete atrioventricular block

Abstract Funding Acknowledgements Type of funding sources: None. Background Leadless pacemakers (LPMs) represent a seductive alternative to conventional pacing. First generation of Micra transcatheter pacing system was able to provide single-chamber VVI(R) pacing mode only, with a potential risk of pacemaker syndrome in sinus rhythm patients. A 2nd generation system (AV) now provides atrioventricular synchrony through atrial mechanical sensing capability (VDD mode). Purpose We sought to compare VR and AV systems in patients with sinus rhythm and chronic ventricular pacing 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 ventricular pacing burden &amp;lt;20% at 1-month post-implantation were excluded. Results A total of 80 patients – 35 VR (2015-2020) and 45 AV (2020-2021) – were included. VR and AV patients had similar baseline characteristics, except for that VR patients being older (82±8 versus 77±9 years, p=0.01). Mean ventricular pacing burden was 75% in the VR and 79% in the AV group (p=0.63). In AV patients, median atrioventricular synchronous beats rate was 77%, 67% having a &amp;gt;66% rate. An E/A ratio &amp;lt;1 as measured on echocardiography was the only independent predictor of accurate atrial mechanical tracking (adjusted OR=13, p=0.006). One-year survival rate was 86% in the VR group and 95% in the AV group (adjusted p=0.21). Two patients in the VR and 0 in the AV group eventually developed pacemaker syndrome in the 1st year post-implantation (p=0.07). Conclusion In sinus rhythm patients with chronic ventricular pacing for complete atrioventricular block implanted with an LPM, atrial mechanical sensing algorithm allowed significant atrioventricular synchrony in most patients, and was associated with no occurrence of – otherwise rare – pacemaker syndrome.

New generation of LCPM and left atrial strain: a promising predictor of atrio-ventricular synchrony in leadless pacemaker pacing

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Leadless cardiac pacemakers (LCPMs) are a new alternative to traditional transvenous pacemaker. They recently have evolved from a single chamber VVI-R pacemaker to devices that can provide atrio-ventricular synchrony (AVS) in patient with sinus rhythm through an 3-axis accelerometer, detecting atrial contractions. To date, Micra AV Transcatheter Pacing System (Medtronic) is the only LCPM on the market that provides AVS. Purpose Many efforts have been made to identify clinical predictors of a good A4 signal amplitude, that determines the ability of the Micra-AV to pace while maintaining AVS (1). Our exploratory study investigates the utility of Left Atrial strain (LAs) for this purpose. Methods Data was extracted from the Cardiac Interventional Registry implemented at our hospital and approved by local ethic committee. Six patients, implanted with Micra-AV (72±13 years), underwent to a complete echocardiography focused on left atrium (LA). Morphological (LA diameters, 2d LA volume and 2d LA area) and functional (EA ratio and LAs study) parameters were assessed. An echocardiography core laboratory studied LAs (Figure A), using a dedicated software (Philips, Epiq 7-Auto Strain Tomtec Application): LA Reservoir Strain (LAsr), LA Conduit Strain (LAscd) and LA Contraction Strain (LAsct) were measured (2). All patients after implantation had a complete electronic control of leadless pacemaker to assess A4 wave amplitude. Results We found that A4 wave amplitude was inversely correlated to 2D-LA volume (Spearman's coefficient rho=-0.96; p=0.003), while it was positively related to LAsr (rho=0.81; p=0.05) and LAsct absolute value (Figure B). In the last years, in addition to the traditional echocardiographic parameters, LA was studied with a new functional parameter, LAs (3). The MARVEL2 study showed that A4 amplitude is fundamental to ensure a high AVS percentage; it was directly related to a parameter defined generically "atrial strain" (4). It is known that LAs is a complex parameter that indicates how the left atrium works overall. Today, thanks to the technological developments of the new echocardiographic software, it can be evaluated more precisely in its components. According to our preliminary data the components that predict A4 amplitude are specifically LAsr and LAsct: we found higher value of A4 in patients that have grater absolute value of these LAs parameters. LAsr is related to the atrial filling and depends on atrial stiffness and fibrosis, LAsct is an indicator of LA ability to empty, thus contributing to the final stage of ventricular diastolic filling. These are simple measurable parameters of LA functional capacity and they seem capable of predicting the possibility of a good AVS in LCPM pacing. Conclusion Patient selection is crucial to obtain good clinical outcomes. In this context, echocardiographic parameters and particularly the LAs study look promising to make a correct choice.

P447 TRANSCATHETER PACING SYSTEM IMPLANT: IS IT A MATTER OF GENDER?

Abstract Background The use of a leadless pacing system, like Micra Transcatheter Pacing System (M–TPS), is nowadays a convincing alternative to transvenous pacemaker. PURPOSE: The study aimed to investigate feasibility and long–term electrical outcomes of M–TPS implant in a real–world population and to estimate sex differences in leadless pacing. Methods All patients undergone M–TPS implantation in our Institution from May 2014 to October 2022. Device follow–up was scheduled at discharge, after 1 month from procedure and then every 6 months. Electrical performance was checked. Major complications were defined as life– threatening events, requiring surgical intervention or any event causing significant hemodynamic instability or resulting in death. Study population was divided between genders to analyze potential differences and those observed during the follow–up (FU). Results One hundred ninety–three consecutive patients [148 males, 76.7%, mean age 79 (IQR 73–84) years] were enrolled in the study. There were no statistically significant differences between groups for demographics characteristics (mean age at implant 79 vs 81, p=0.12), except gender. The mean FU was 12 (IQR 1–36) months, maximum 8 years. The implant procedure was effectuve in all patients and no complications were recorded. We observed no differences between groups in procedure duration [40 (IQR 30–60) min vs 40 (IQR 29–50), p=0.64], fluoroscopy time [9 (6–14) min vs 9 (7–11), p=0.81] and single device delivery (65.7% vs 65.9%, p=0.34). Electrical performance, except for pacing threshold at implantation [0.5 (IQR 0.38–0.75) V/0.24ms vs 0.38 (IQR 0.25–0.63) V/0.24ms, p=0.02), was similar between groups at discharge [pacing threshold 0.38 (IQR 0.38–0.63) V/0.24 ms vs 0.38 (IQR 0.25–0.55) V/0.24 ms, p=0.30; impedance 650 (IQR 560–760) Ohm vs 675 (IQR 580–780) Ohm, p=0.71; R wave amplitude 10.1 (IQR 7–16.2)mV vs 9.5 (IQR 7–14.45) mV, p=0.71] and during the FU [pacing threshold 0.5 (IQR 0.38–0.63) V/0.24 ms vs 0.5 (IQR 0.38–0.5) V/0.24 ms, p=0.11; impedance 570 (IQR 490–630) Ohm vs 580 (IQR 510–640) Ohm, p=0.46; R wave amplitude 11.5 (IQR 7.8–15.7)mV vs 12.7 (IQR 9–18) mV, p=0.26]. Conclusion Leadless pacing therapy is a feasible and safe alternative to conventional pacemakers with comparable electrical performance and outcomes even during a long–term FU. No differences were found between genders making it a good option especially in women who are often considered fragile in surgical procedures.

The VR leadless pacemaker: Results of an expert panel using the RAND/UCLA method.

Leadless pacemakers were developed to reduce complications associated with transvenous pacemaker implantation and long-term follow-up. Existing international guidelines lack detailed instructions on patients suitable for leadless pacemaker implantation. Our aim was to develop a consensus document that provides medical guidance for all health professionals involved in the indication and implantation of Transcatheter Pacing System single-chamber device (VR leadless) pacemakers for patients with atrial fibrillation or in sinus rhythm. A panel of experts, including interventional and non-interventional cardiologists, used the Research ANd Development/University of California at Los Angeles (RAND/UCLA) method to rate the appropriateness of leadless pacemaker implantation for 64 scenarios in patients with atrial fibrillation and 192 scenarios in sinus rhythm. The scenarios were rated individually and again during a moderated group session. Median ratings and level of agreement were calculated to classify each scenario as appropriate, inappropriate, or questionable. This consensus statement, based on available literature and the experts' opinions, summarizes recommendations for standardizing and optimizing leadless pacemaker implantation. The limitation for vascular access via the superior vena cava was the most influential variable when indicating leadless pacemaker implantation in both patients with atrial fibrillation and patients in sinus rhythm. Life expectancy, risk of infection, prosthetic valve, left ventricular ejection fraction (LVEF), limitation for vascular access via the superior vena cava, and mobility and exercise capacity determine who is advised to undergo VR leadless pacemaker implantation. More prospective studies are needed to optimize existing recommendations.

Usefulness of leadless pacemaker implantation to continue chemotherapy for Burkitt's lymphoma without device infection despite repeated systemic infections.

Usefulness of leadless pacemaker implantation to continue chemotherapy for Burkitt's lymphoma without device infection despite repeated systemic infections.