Leadless pacing: DDD-all goals achieved?

BackgroundCardiac pacing has been shown to improve quality of life and prognosis of patients with bradycardia for almost 60 years. The latest innovation in pacemaker therapy was miniaturization of generators to allow leadless pacing directly in the right ventricle. There is a long history and extensive experience of leadless ventricular pacing in Austria. However, no recommendations of national or international societies for indications and implantation of leadless opposed to transvenous pacing systems have been published so far.ResultsA national expert panel of skilled implanters gives an overview on the two utilized leadless cardiac pacing systems and highlights clinical advantages as well as current knowledge of performance and complication rates of leadless pacing. Furthermore, a national consensus for Austria is presented, based on recent studies and current know-how, specifically including indications for leadless pacing, management of infection, suggestions for qualification, and training of the operators and technical standards.ConclusionsLeadless pacing systems can be implanted successfully with a low complication rate, if suggestions for indications and technical requirements are followed.Condensed abstractAn overview of the two utilized leadless cardiac pacing systems is given, specifically highlighting clinical advantages as well as current knowledge of performance and complication rates. Furthermore, a national consensus for Austria is presented, specifically including indications for leadless pacing, management of infection, and suggestions for qualification and technical standards.

Over the past decade, leadless pacing has undergone a rapid evolution, resulting in multiple leadless pacemaker (LPM) devices that offer advancements such as atrioventricular synchronized pacing in VDD mode, atrial stimulation, dual-chamber pacing, and longer battery longevity. Studies comparing LPMs with transvenous pacemakers (TVPMs) show a lower rate of device-related complications with LPMs. In the near future, LPMs could be combined with other devices such as non-transvenous implantable cardioverter-defibrillators to provide anti-tachycardia pacing or bradycardia pacing. Future prospectives for leadless cardiac resynchronization therapy and leadless conduction system pacing are being investigated. As LPMs continue to improve, their applications are anticipated to expand further improving patient outcome, promising a bright future for leadless pacing. In this review, the past, present, and future of leadless pacing are discussed with a focus on cutting-edge implantation techniques, clinical outcomes, and modern advancements of LPMs.

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.

PO-05-026 IMPACT OF LEADLESS PACING ON VENTRICULAR AND VALVULAR FUNCTION

Advances in management of electrophysiology and atrial fibrillation in the cardiac catheter laboratory: implications for anaesthesia

Background: Leadless pacemakers have gained popularity in providing permanent pacing in select patient populations. Pacemaker mediated tachycardia and arrhythmias have been well described in patients with dual chamber pacemakers, but up to this point not in leadless pacing. Case Description: A 91-year-old female with symptomatic bradycardia and 2:1 AV block underwent implantation of a Micra AV pacemaker programmed VDD 60-100 bpm. Five months later, she presented with decompensated heart failure with a heart rate of 88 bpm and a newly reduced left ventricular ejection fraction of 30%. Device interrogation showed 95% ventricular pacing, with 91% AV synchrony. The Micra was found to be tracking an atrial rhythm between 80-100 bpm more than 80% of the time (Figure 1A). RV pacing induced cardiomyopathy was suspected and she underwent placement of a bi-ventricular pacemaker. During implant, a short VA time was noted and changes in the V-V cycle length predicted changes in the A-A cycle length (Figure 1B). Micra ventricular pacing was held resulting in an AV paced rhythm from the CRT system and a drop in rate to 60 bpm (Figure 1C). These results indicate that the Micra pacemaker was tracking the atrial mechanical contraction (AM) from a retrograde conducted P-wave resulting in elevated heart rates from a pacemaker-driven arrhythmia. Discussion: In patients with poor AV conduction, intact VA conduction, and SA node dysfunction, Micra AV may create pacemaker mediated arrhythmia by tracking the AM of the retrograde conducted P-wave. Careful patient selection to avoid Micra AV placement in patients with SA node dysfunction, and close attention to the rate histogram on device interrogation may prevent development and facilitate recognition of this unique cause of pacemaker-mediated arrhythmia.

Approach to pacing in patients with various septal defects

BackgroundSingle chamber atrial pacing (AAI) provides a disease-specific treatment for sick sinus syndrome (SSS) but has largely been replaced by DDD pacing. With the advent of leadless atrial pacemakers (PM), there is growing interest in long-term follow-up data in patients with SSS and an AAI pacemaker.PurposeTo assess the incidence of system upgrade in patients treated with AAI-PM for SSS during long-term follow-up.MethodsThis is an analysis of prospectively enrolled patients undergoing implantation of an AAI-PM. Wenckebach block point (WBP) was measured at implantation and serially during follow up.ResultsWe included 178 patients (58% female, median age at implantation 77 [71–83] years). The median follow-up duration was 6.5 [2.0–9.7] years. Twenty-three patients (13%) received a system upgrade to a DDD system, corresponding to a yearly upgrade rate of 2.0%. Median time to system upgrade was 5.2 [1.6–8.7] years. Reasons for system upgrade were higher-degree AVB (39%), atrial arrhythmias (35%), low WBP (17%), and syncope (9%). Median WBP at implantation was 130 [120–140] bpm, showing a significant decline over time in the upgrade-group compared to the rest of the cohort with 103 [91–130] bpm vs. 130 [120–130] bpm (p = 0.011).ConclusionIn this cohort of patients undergoing AAI-PM implantation for SSS, upgrade to a DDD system was low during long-term follow-up. Therefore, AAI pacing for the treatment of SSS may be considered a patient-tailored treatment option, especially in light of novel leadless pacing therapies.Graphical abstractCentral Illustration: AF = atrial fibrillation; AT = atrial tachycardia; AVB = atrioventricular block; WBP = Wenckebach block point; AAI = single-chamber atrial stimulationSupplementary InformationThe online version contains supplementary material available at 10.1007/s10840-025-02061-4.

The primary objective was to determine whether technical and nontechnical performances were in some way correlated during immersive simulation. Performance was measured among French Emergency Medical Service workers at an individual and a team level. Secondary objectives were to assess stress response through collection of physiologic markers (salivary cortisol, heart rate, the proportion derived by dividing the number of interval differences of successive normal-to-normal intervals > 50 ms by the total number of normal-to-normal intervals [pNN50], low- and high-frequency ratio) and affective data (self-reported stress, confidence, and dissatisfaction), and to correlate them to performance scores. Prospective observational study performed as part of a larger randomized controlled trial. Medical simulation laboratory. Forty-eight participants distributed among 12 Emergency Medical System teams. Individual and team performance measures and individual stress response were assessed during a high-fidelity simulation. Technical performance was assessed by the intraosseous access performance scale and the Team Average Performance Assessment Scale; nontechnical performance by the Behavioral Assessment Tool for leaders, and the Clinical Teamwork Scale. Stress markers (salivary cortisol, heart rate, pNN50, low- and high-frequency ratio) were measured both before (T1) and after the session (T2). Participants self-reported stress before and during the simulation, self-confidence, and perception of dissatisfaction with team performance, rated on a scale from 0 to 10. Scores (out of 100 total points, mean ± SD) were intraosseous equals to 65.6 ± 14.4, Team Average Performance Assessment Scale equals to 44.6 ± 18.1, Behavioral Assessment Tool equals to 49.5 ± 22.0, Clinical Teamwork Scale equals to 50.3 ± 18.5. There was a strong correlation between Behavioral Assessment Tool and Clinical Teamwork Scale (Rho = 0.97; p = 0.001), and Behavioral Assessment Tool and Team Average Performance Assessment Scale (Rho = 0.73; p = 0.02). From T1 to T2, all stress markers (salivary cortisol, heart rate, pNN50, and low- and high-frequency ratio) displayed an increase in stress level (p < 0.001 for all). Self-confidence was positively correlated with performance (Clinical Teamwork Scale: Rho = 0.47; p = 0.001, Team Average Performance Assessment Scale: Rho = 0.46; p = 0.001). Dissatisfaction was negatively correlated with performance (Rho = -0.49; p = 0.0008 with Behavioral Assessment Tool, Rho = -0.47; p = 0.001 with Clinical Teamwork Scale, Rho = -0.51; p = 0.0004 with Team Average Performance Assessment Scale). No correlation between stress response and performance was found. There was a positive correlation between leader (Behavioral Assessment Tool) and team (Clinical Teamwork Scale and Team Average Performance Assessment Scale) performances. These performance scores were positively correlated with self-confidence and negatively correlated with dissatisfaction.

Leadless pacing has become an alternative approach for patients requiring a single-chamber pacemaker. Conventionally, leadless Micra Transcatheter Pacing System (TPS) pacemakers are implanted via a right femoral venous access. However, due to various reasons, a left-sided femoral venous approach may be necessary. We hypothesized that a left-sided femoral venous approach is as safe and effective when compared with a right-sided approach. We assessed indications, procedural characteristics, safety and mid-term outcomes of Micra TPS implantation via a left femoral venous approach when compared with the conventional right-sided approach. In this retrospective single-centre analysis, 143 consecutive patients undergoing Micra TPS implantation were included. 87% (125/143) underwent Micra TPS implantation via a right, and 13% (18/143) via a left femoral venous access. The mean age at implantation was 79.8 ± 7.5 years. Acute procedural success, mean procedure and fluoroscopy times as well as device parameters at implantation and follow-up (mean 15 ± 11.5 months) were similar between the two groups. Five major complications (3.5%) were encountered, all using a right-sided approach. After a transfemoral TAVI procedure, left femoral venous access was used in 42% of cases when compared with 8% in the remaining population (P = 0.003). A left femoral venous access for Micra TPS implantation is safe and effective with an excellent implantation success rate similar to a conventional right femoral venous access without longer implantation and fluoroscopy times. The most frequent reason for choosing left vs. right femoral venous access was a previous transfemoral TAVI procedure.

No reports on atrial leadless pacing have been demonstrated in patients with the Fontan palliation. We present the case of a patient with a Lateral tunnel Fontan palliation with leadless pacing system for symptomatic bradycardia in the setting of sinus node dysfunction. After internal review board approval, a retrospective case review was performed with follow-up of atrial leadless pacing in a patient with a Lateral tunnel Fontan. A 32-year-old male with a medical history of tricuspid atresia status post: Blalock-Taussig Shunt (BT) shunt, Glenn procedure, and Fontan surgery at 5 years of age presented with persistent atrial flutter and a history of symptomatic heart failure in the setting sick sinus syndrome with a dual chamber epicardial pacemaker procedure. After ablation of his intra-atrial re-entrant tachycardia he continued with symptomatic bradycardia in the setting of epicardial lead fracture. Implant values demonstrated an atrial threshold of 1 Volts (V) at 0.4 ms (ms), impedance at 820 ohms and sensing at < 1 mV. He was programmed AAIR (VVIR) 80-130 bpm, rate response of 2/7, and discharged on apixaban 5 mg twice a day. Follow-up at 4 months demonstrated no intracardiac thrombus, 98% atrial pacing, threshold of 0.75 V@0.15 ms, impedance of 590 ohms, and R-wave of 2.5 mV. The estimated device longevity was 17.2 years. Atrial leadless pacing is feasible in the lateral tunnel Fontan. Larger patient population data sets are needed to assess safety of this type of pacing long-term.

Leadless pacemakers: The leap from single to dual chamber pacing

Leadless pacemakers (LPMs) are an established alternative to transvenous pacing systems for the treatment of bradyarrhythmias. This review outlines the evolution of LPMs, summarizes available safety and efficacy data, and highlights future development for leadless systems and the challenges that lie ahead. Data from prospective cohort studies, large patient registries, and meta-analyses demonstrate high implantation success rates and fewer long-term complications with LPMs when compared to transvenous systems. Recent advances in leadless systems include dual-chamber devices capable of atrial and ventricular synchronous pacing and LPMs integrated with subcutaneous defibrillators. Future directions for leadless systems include leadless cardiac resynchronization therapy and leadless conduction system pacing. However, unresolved issues remain, including management of device end of life. LPMs are transforming cardiac pacing by reducing complications frequently observed with transvenous systems. Continued technological refinement and long-term clinical evaluation will guide broader adoption and optimize outcomes.

Introduction Leadless pacing is increasingly used in patients with contraindications to transvenous systems. However, a common presentation of life-threatening bradyarrhythmia is in the out-of-hours emergency setting. The perceived complexities of leadless implantation anecdotally inhibit their use as destination devices implanted in the acute setting. Our centre offers a 24-7 emergency pacing service, we examined our use of leadless pacemaker implantation for patients requiring out of hours emergency pacing at our centre from December 2021 to December 2023. Purpose The purpose of this study looking to examine the feasibility and safety of leadless pacing in out of hours emergency situations. Methods This is a single centre retrospective cohort study examining all patients (pts) undergoing leadless pacemaker implantation at 1 hospital. Out of hours (OOH) implantation was defined as being after 18:00 during the week and any time during the weekend. Clinical and procedural parameters were compared between in-hours and out of hours (OOH) implantation. Haemodynamic instability was defined as any patient requiring inotrope support. Results 118 leadless pacing systems were implanted between 0/1/12/2021 and 01/12/2023; 95 being performed in-hours and 23 OOH. Pacing indication was high-degree AV block in 20 pts (87%) in the OOH group, with frailty (8pts), dialysis (4pts) and infection (3pts) being listed as the most common reasons for selection of a leadless system in the OOH group. OOH pts had greater haemodynamic instability [in-hours: 3pts (3.2%) vs OOH: 4pts (17.4%)]. Procedural time (mean ± Standard deviation, mins) was similar between groups [52.4 (±3.6) in-hours vs 59.7(+/- 6.4) OOH; p= 0.33] as was fluoroscopy time (mins) [in-hours: 4.9 (+/- 1.0) vs OOH: 5.1(+/- 2.3) p=0.97] and radiation dose (cGy*cm²) [in-hours: 56.73 (+/- 9.87) vs OOH: 53.8(+/- 14.1), p=0.89]. 3 (3.1%) major complications occurred in the in-hours group [tamponade (2pts), infection (1pt)]. One pt in the OOH group had a significant post procedure access site bleed (4.3%), but no tamponade occurred in this group. Four pts (4.2%) died before discharge in the in-hours group, four patients (17.4%) died in the OOH group, reflecting their poor premorbid condition. Conclusions Leadless pacemakers can be safely implanted in the emergency, out of hours setting. In selected patients, this technology can offer an immediate destination therapy as an important alternative to placing a temporary system.

Background: Recently introduced leadless cardiac pacemakers effectively overcome all lead-related limitations of conventional pacemaker systems. However, these devices only feature single-chamber pacing capability although dual-chamber pacing is highly desirable due to physiologic reasons. Implanting a leadless pacemaker into the right atrium and a second one into the right ventricle would enable leadless dual chamber pacing but requires wireless communication for device synchronization. Conventional radiofrequency telemetry is not suitable for this purpose due to its high energy consumption. Thus, an ultra-low power wireless communication method is crucial to preserve the pacemaker’s longevity (modern pacemakers consume only 5-10 µW of power). Purpose: Dual-chamber pacing capability for leadless pacemakers. Methods: Two pacemakers were developed that feature bidirectional wireless communication. Intra-body communication was implemented as communication method. This method uses the electrical conductivity of blood and tissue: the data from one device is modulated and applied as a small alternating current signal to the myocardial tissue and blood via electrodes. The signal is registered almost simultaneously by the other device. The communication frequency is ~100 kHz and therefore does not influence the heart’s functioning. The pacemakers feature an electrode pair for bipolar stimulation, the communication is performed over the same electrodes. The pacemakers were tested in an acute in-vivo trial on a 60 kg domestic pig. One pacemaker paced the right atrium, the other one the right ventricle. The atrial pacemaker served as master device and dictated the actual pacing rate, the atrioventricular (AV) pacing delay and pacing activity to the ventricular pacemaker in a wireless manner. Results: The pacemakers successfully performed dual-chamber pacing (D00) with wireless intra-body communication using the myocardium and blood as transmission path. No interference with the cardiac function was observed. The ECG sequence in Figure 1 shows the onset of leadless dual-chamber pacing recorded during the in-vivo trial: the atrial (A) and ventricular (V) pacing spikes are indicated by the arrows. The pacing rate was set to 120 bpm and the AV delay to 50 ms. Less than 1 µW average power was applied to the tissue for wireless communication. Conclusion: To our knowledge, this is the first report on successful leadless dual-chamber pacing during an in-vivo trial. Intra-body communication was integrated into a pacemaker system and has proven to be a promising, power-efficient wireless communication method for leadless dual-chamber pacemakers.