European Journal of Cardiovascular Medicine

Conventional transvenous pacemakers provide established and versatile bradycardia therapy, yet their pocket and transvenous leads can be sources of infection, venous obstruction, lead failure, and reintervention. Leadless pacemakers place the pacing system within the heart and thereby avoid a chest pocket and transvenous lead. They do not eliminate procedural risk: femoral venous access, large delivery systems, intracardiac fixation, perforation, and device retrieval remain important considerations. The 2025 state-of-the-art review by Saleem-Talib and colleagues describes the rapid expansion of leadless pacing from single-chamber ventricular devices to systems capable of atrial mechanical tracking and dual-chamber pacing, while emphasizing patient selection and the continuing limitations of the technology [1].

Early clinical experience with the Nanostim system demonstrated stable electrical performance through one year among 31 patients available for follow-up, with no pacemaker-related adverse events reported between months 3 and 12; the study also documented stable pacing thresholds, R-wave amplitudes, and impedance [2]. More recently, the AVEIR DR system has extended leadless pacing to a two-device, communicating dual-chamber configuration. These advances broaden the potential use of leadless pacing, but do not make all patients with atrioventricular block suitable for a leadless system. The present case series describes five patients treated with contemporary leadless pacing systems and reports the clinical and device information available in their records.

This descriptive case series includes five patients who underwent leadless pacemaker implantation at PSG Hospitals, Coimbatore, between January 2024 and April 2026. Information was abstracted from the clinical and device follow-up records supplied for manuscript preparation. Variables included age, sex, relevant comorbidities, pacing indication, device system, implantation information, available electrical measurements, and documented follow-up. No inferential statistical testing was performed; results are presented as individual patient observations and descriptive counts. Because this is a five-patient case series without a control group, no comparative effectiveness or safety inference is intended.

Patient-level data and follow-up measurements are reported as documented. Where a value or date was not available in the supplied records, it is identified as not documented rather than estimated. Device-reported atrial mechanical sensing with ventricular pacing is reported as a pacing-distribution metric and is not equated with independently measured atrioventricular synchrony.

An 85-year-old man with diabetes mellitus, hypertension, hypothyroidism, and haemodialysis-dependent chronic kidney disease presented with trifascicular conduction disease and intermittent 2:1 atrioventricular block. A Micra AV VDD leadless pacemaker was implanted. The recorded implant measurements were an R-wave amplitude of 5.6 mV, pacing threshold of 0.50 V at 0.24 ms, and impedance of 1230 Ω. At the latest follow-up, approximately 2 years after Micra AV implantation, the patient was clinically well. Device interrogation was reported as satisfactory, with no device-related complication during the follow-up.

Patient 2

An 82-year-old man with rheumatoid arthritis, interstitial lung disease, diabetes mellitus, and hypothyroidism had complete atrioventricular block. He received a Micra AV VDD leadless pacemaker. Recorded implant measurements were an R-wave amplitude of 18.6 mV, pacing threshold of 1.25 V at 0.24 ms, and impedance of 930 Ω. At the latest follow-up, approximately 2 years after Micra AV implantation, the patient was clinically well. Device interrogation was reported as satisfactory, with no device-related complication during the follow-up.

Patient 3

An 83-year-old woman with chronic obstructive pulmonary disease and Type 2 DM, S Hypertension , Vascular Dementia source record presented with complete atrioventricular block and underwent Micra AV implantation. Recorded measurements were an R-wave amplitude of 15.3 mV, pacing threshold of 0.25 V at 0.24 ms, and impedance of 1030 Ω. At the latest follow-up, approximately 1 years after Micra AV implantation, the patient was clinically well. The ECGs illustrating complete heart block and the post-implant Micra VDD rhythm are shown in Figure 1A and Figure 1B, respectively. Figure 4 showed  Device interrogation and  was satisfactory, with no device-related complication during the follow-up.

Patient 4

A 63-year-old woman with diabetes mellitus, Peripheral Vascular Disease underwent Peripheral Angioplasty,  hypertension, and Parkinson’s disease had intermittent complete atrioventricular block and received a Micra AV VDD system. The available acute measurements included an R-wave amplitude of 5.2 mV and impedance of 550 Ω; an acute pacing threshold was not available in the records used for this rewrite. At interrogation on 25 October 2026, the R-wave amplitude was 10.7 mV, threshold 0.25 V at 0.24 ms, impedance 660 Ω, and estimated battery longevity greater than 10 years. The device report listed atrial mechanical sensing with ventricular pacing in 95.3% and ventricular pacing without atrial tracking in 4.7% of the reported pacing distribution..On follow up the patient was clinically well. Device interrogation was reported as satisfactory, with no device-related complication during the follow-up.

Patient 5

A 77-year-old male with diabetes mellitus, benign prostatic hyperplasia, Parkinson’s disease, and vascular dementia had intermittent complete atrioventricular block and received an Abbott AVEIR DR dual-chamber leadless pacemaker. The ventricular capsule was positioned at the right ventricular apical septum and the atrial capsule in the right atrial appendage; the programmed mode was DDDR 60–130 beats/min. At the available interrogation, atrial sensing amplitude was 1.2 mV, atrial threshold 0.5 V, programmed atrial output 2.5 V at 0.24 ms, and atrial impedance 580 Ω. Ventricular sensing amplitude was greater than 10 mV, ventricular threshold 0.5 V, programmed ventricular output 2.5 V at 0.24 ms, and ventricular impedance 900 Ω. The ECGs illustrating the rhythm before and after AVEIR DR implantation are shown in Figure 2A and Figure 2B, respectively. The post-implant fluoroscopic image demonstrating the atrial and ventricular capsules is shown in Figure 3. The ventricular and atrial current-of-injury recordings during capsule implantation are shown in Figure 5A and Figure 4B, respectively. Follow-up records spanned approximately five months, from 27 April to 30 September 2026. The clinical characteristics, indications for leadless pacemaker implantation, device types, implantation measurements, and follow-up outcomes of the five patients are summarized in Table 1.

Leadless pacing has evolved from a solution for patients requiring ventricular-only pacing into a technology that can support atrioventricular (AV)-synchronous and dual-chamber pacing. The five patients in this series illustrate how these developments can be applied to older adults with AV conduction disease and substantial comorbidity. Their presentations ranged from intermittent high-grade AV block to complete heart block, highlighting the need to match the pacing strategy to each patient’s rhythm and clinical circumstances.

Conventional transvenous pacemakers remain an established treatment for bradyarrhythmias. However, their generator pocket and transvenous leads may be disadvantageous in patients with limited venous access, haemodialysis requirements, or increased infection risk. The 2021 European Society of Cardiology (ESC) pacing guideline identifies venous obstruction, pocket-related concerns, and increased infection risk—including in patients receiving haemodialysis—as circumstances in which leadless pacing may be considered. The guideline also emphasizes individualized patient selection, given the limited long-term comparative evidence available at the time [1]. Leadless pacing should therefore be viewed as an additional option rather than a universal replacement for transvenous systems.

The first-generation leadless systems primarily provided ventricular pacing. In the Micra Transcatheter Pacing Study, the device met prespecified safety and efficacy goals and demonstrated stable pacing performance at six months [2]. The MARVEL 2 study subsequently showed that an accelerometer-based algorithm could improve AV synchrony in selected patients with sinus rhythm and complete AV block; at rest, 95% of the 40 patients included in the primary efficacy analysis achieved at least 70% AV synchrony during VDD pacing [3]. These findings helped establish the feasibility of atrial mechanical sensing, although AV synchrony may vary with posture, activity, and patient characteristics.

The Micra AV and Micra AV2 systems use accelerometer-based sensing of atrial mechanical activity to support AV-synchronous ventricular pacing. The AVEIR DR system takes a different approach, using separate right atrial and right ventricular leadless devices that communicate to provide dual-chamber pacing. In the prospective AVEIR DR i2i study, the dual-chamber system met its primary safety and performance endpoints at three months [4]. These technologies broaden the potential role of leadless pacing, while also introducing device-specific considerations that should inform patient selection.

In this series, follow-up ranged from approximately six months to two years. All five patients remained clinically well, with satisfactory device interrogation at their latest follow-up. The patients described good quality of life during follow-up; however, quality of life was not assessed using a validated instrument. These observations are encouraging but should be interpreted descriptively, given the small cohort and variable follow-up duration.

Available interrogation data demonstrated satisfactory electrical performance. In the patient with a Micra AV2 device, atrial mechanical sensing with ventricular pacing accounted for 95.3% of the device’s pacing distribution. This figure should not be interpreted as a direct measurement of overall AV synchrony. The distinction is important because device pacing categories and AV synchrony are not interchangeable outcomes; AV synchrony requires assessment according to the device’s defined criteria and, where appropriate, objective electrocardiographic evaluation [3,5].

Evidence comparing leadless and transvenous pacing continues to develop. The Micra Coverage with Evidence Development study found fewer chronic complications and reinterventions with leadless pacing than with single-chamber transvenous pacing in a large real-world cohort, although observational comparisons cannot eliminate all potential confounding [6]. Contemporary reviews also emphasize that leadless systems avoid pocket- and lead-related complications but retain important risks, including cardiac perforation, and that long-term device management remains a consideration [5,7]. These trade-offs are particularly relevant when selecting a device for patients with complex comorbidities.

This series has several limitations. It includes only five patients, has no comparator group, and has relatively short and variable follow-up. The observations are descriptive and cannot establish comparative safety, efficacy, or long-term durability. Quality of life was not measured using a validated scale, and the pacing distribution in an individual device interrogation should not be treated as a substitute for a standardized AV-synchrony assessment. Larger studies with systematic follow-up and standardized clinical, electrical, and patient-reported outcomes are needed.

Left ventricular function remained preserved on echocardiographic assessment, and none of the five patients developed clinical heart failure during the available follow-up. No cardiac perforation or other device- or procedure-related complication was observed. These findings are reassuring in this small series, particularly because cardiac perforation is a recognized potential complication of leadless pacemaker implantation. However, the absence of complications in five patients should be interpreted as a descriptive observation and not as evidence that leadless pacing eliminates procedural or long-term risk.

In conclusion, this series illustrates the practical use of leadless pacing in selected patients with AV conduction disease and complex comorbidities. The favourable clinical course and satisfactory device function observed during follow-up support leadless pacing as an option within an individualized pacing strategy. Device selection should remain patient-specific, with the benefits and limitations of each system considered alongside the patient’s pacing requirements and long-term clinical needs

In this five-patient case series, leadless pacemakers provided pacing support for advanced atrioventricular conduction disease in older patients with substantial comorbidity. All five patients were reported to have a good quality of life during follow-up, and no procedural complications were reported in the records reviewed. The cases illustrate the use of Micra AV/AV2 and AVEIR DR systems and highlight the importance of individualized device selection, careful implantation, and continued device surveillance. These encouraging observations are descriptive and should be interpreted in the context of the small, uncontrolled series; they do not establish comparative benefit or long-term safety

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2.      Reynolds D, Duray GZ, Omar R, et al. A leadless intracardiac transcatheter pacing system. N Engl J Med. 2016;374(6):533–541. doi:10.1056/NEJMoa1511643.

3.      Steinwender C, Khelae SK, Garweg C, et al. Atrioventricular synchronous pacing using a leadless ventricular pacemaker: results from the MARVEL 2 study. JACC Clin Electrophysiol. 2020;6(1):94–106. doi:10.1016/j.jacep.2019.10.017.

4.      Knops RE, Reddy VY, Ip JE, et al. A dual-chamber leadless pacemaker. N Engl J Med. 2023;388(25):2360–2370. doi:10.1056/NEJMoa2300080.

5.      Saleem-Talib S, Hoevenaars CPR, Molitor N, et al. Leadless pacing: a comprehensive review. Eur Heart J. 2025;46(21):1979–1990. doi:10.1093/eurheartj/ehaf119.

6.      Crossley GH, Piccini JP, Longacre C, et al. Leadless versus transvenous single-chamber ventricular pacemakers: 2-year outcomes from the Micra Coverage with Evidence Development study. Heart Rhythm. 2021;18(9):1571–1578.

7.     Breeman KTN, Tjong FVYT, Miller MA, et al. Ten years of leadless cardiac pacing. J Am Coll Cardiol. 2024;84(21):2131–2147. doi:10.1016/j.jacc.2024.08.077