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

BACKGROUND

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.

CONCLUSIONS

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.

Second Micra leadless pacemaker implantation by using intracardiac echocardiography

The strategy after battery depletion was not established in Micra leadless pacemaker system (Micra). There are still some concerns in the 2nd Micra implantation, such as the mechanical interaction between both devices. The position of the 2nd Micra should be placed apart from the 1st Micra. We present a case of 1st Micra battery depletion who successfully underwent the 2nd Micra implantation under the intracardiac echo guidance. In our case, intracardiac echo was a very effective tool for confirming the location of Micra implantation.

Leadless pacemakers: Where are we?

Pacemakers have been the cornerstone of brady-arrhythmia management since the mid-20th century. Despite the widespread use and success of traditional transvenous pacemakers, they are associated with an estimated 15 % complication rate at three years. Driven by the advantages over traditional transvenous pacemakers including a lack of transvenous leads, resistance to infection, and ease of implantation, the number of leadless pacemakers placed annually in the United States has dramatically increased since their initial approval. While current iterations of leadless pacemakers lack the versatility offered by transvenous devices, recent advances in leadless pacing offer an increasingly diverse range of therapeutic options. This review will discuss the past, present, and future emerging technologies, and strategies in leadless pacing.

Different leadless pacemakers working in harmony (Aveir in the atrium/Micra AV2 in the ventricle) in a patient with dextrocardia and double outlet right ventricle after high-risk infected device extraction

INTRODUCTION

Patients with congenital heart disease are at increased risk for requiring cardiac pacing during their lifetime.

METHODS

We present the first described case of using two leadless pacing systems manufactured by separate companies implanted within the same patient to provide atrial and ventricular pacing due to complex congenital anatomy.

RESULTS

A 27-year-old male with dextrocardia with double outlet right ventricle, subaortic ventricular septal defect, and pulmonary stenosis status-post pulmonary valve replacement complicated by ventricular pacing dependence and subsequent atrial pacing dependence after atriotomy-based atypical flutter ablation developed recurrent mediastinitis and pocket infection with erosion despite prolonged antibiotic treatment. Due to atrial and ventricular pacing dependence, a comprehensive congenital care team concluded the need for lead extraction and replacement of pacemaker via leadless peacemaking device. Laser-lead extraction and temporary atrial pacemaker placement was performed. Afterward, a transesophageal echocardiogram guided implantation of both a Micra AV 2 (Medtronic) leadless pacemaker in the interventricular septum within the right ventricle and an Aveir (Abbott) leadless pacemaker in the superior base of the right atrial appendage was performed with successful pacing. Although there is no communication between these devices, atrial-mechanical ventricular pacing was reliable with good implant thresholds, impedances and sensing from both devices.

CONCLUSION

Our case demonstrates the feasibility of using dual leadless pacing modalities to simultaneously pace someone at complex, prohibitive risk for temporary permanent or permanent pacemaker devices.

Aveir VR real-world performance and chronic pacing threshold prediction using mapping and fixation electrical data

AIMS

Aveir VR performance and predictors for its pacing threshold (PCT) in a real-world cohort were investigated.

METHODS

Electrical measurements at various stages of an Aveir VR implant were prospectively collected. Predictors for 3-month PCT were studied. A retrospective cohort of consecutive 139 Micra implants was used to compare the PCT evolution. High PCT was defined as ≥1.5 V, using a pulse width of 0.4 ms for Aveir and 0.24 ms for Micra. Excellent PCT was defined as ≤0.5 V at the respective pulse width.

RESULTS

Among the 123 consecutive Aveir VR implant attempts, 122 (99.2%) were successful. The majority were of advanced age (mean 79.7) and small body size (mean BSA 1.60). Two patients (1.6%) experienced complications, including one pericardial effusion after device reposition and one intraoperative device dislodgement. Eighty-eight patients reached a 3-month follow-up. Aveir 3-month PCT was correlated with impedance at mapping (P = 0.015), tether mode (P < 0.001), end-of-procedure (P < 0.001), and mapping PCT (P = 0.035), but not with PCTs after fixation (P > 0.05). Tether mode impedance >470 ohms had 88% sensitivity and 71% specificity in predicting excellent 3-month PCT. Although it is more common for Aveir to have high PCT at end of procedure (11.5% for Aveir and 2.2% for Micra, P = 0.004), the rate at 3 months was similar (2.3% for Aveir and 3.1% for Micra, P = 1.000).

CONCLUSION

Aveir VR demonstrated satisfactory performance in this high-risk cohort. Pacing thresholds tend to improve to a greater extent than Micra after implantation. The PCT after fixation, even after a waiting period, has limited predictive value for the chronic threshold. Low-mapping PCT and high intraoperative impedance predict chronic low PCT.

A case of endocardial dissection caused by Micra implantation

BACKGROUND

Leadless pacemakers are a recent technological advancement. It has many advantages, but there are still a few serious complications.

CASE PRESENTATION

This article reports the case of a patient with an endocardial tear and dissection caused by contact with the tip of the Micra cup during surgery and summarises the relevant data.

CONCLUSIONS

This case report details the occurrence and management of the incident and provides some guidance for future clinical management.

Improving outcomes in single chamber leadless pacemakers: strategies for minimizing vascular complications

BACKGROUND

Leadless pacemaker therapy is associated with a significant reduction in lead-related complication rate compared to conventional transvenous single chamber pacemaker therapy. However, a significant complication rate of 1.2% was observed in vascular access due to the use of large delivery femoral sheath (27Fr). The aim of this study was to evaluate the effectiveness of real-time ultrasound guidance and Z suture technique in reducing total and major vascular complications in leadless pacemaker therapy.

METHOD

In this study, we performed a retrospective and prospective analysis of all adverse events associated with leadless pacemaker (Micra) implantation by two operators at a single tertiary center from December 2016 to December 2018. To mitigate the risk of vascular complications, all patients underwent real-time ultrasound-guided venipuncture for vascular access, as well as the application of a Z-suture technique for hemostasis at the end of the procedure. Data were collected on implant indications, implant procedure details, complications, and follow-up information.

RESULTS

In this study, 45 patients with an age range of 24 to 94 years (mean 76 ± 14 years) were recruited, with 21 (46.6%) being female. The pacing indications for the patients included atrial fibrillation (24, 53.3%), vascular (7, 15.5%), infection (9, 20%), cognitive/frailty (3, 6.6%), and occupational (2, 4.4%). The implant procedures were performed under general anesthesia in 6 (13.3%) of the cases, and under local anesthesia and sedation in 39 (86.6%) of the cases. A single deployment was achieved in 43 (95.5%) of the patients, while 2 deployments were required in 2 (4.4%) of the patients. Notably, no vascular or major complications were reported in our cohort of patients.

CONCLUSIONS

The results of this observational study indicate that incorporating real-time ultrasound guidance during venipuncture and the use of a Z-suture technique significantly reduce the occurrence of both total and major vascular complications associated with the implantation of leadless pacemaker. However, more robust and larger studies are required in order to confirm these results and implications for clinical practice.

Safety and Performance of the Micra VR Leadless Pacemaker in a Japanese Cohort - Comparison With Global Studies

BACKGROUND

The Micra leadless pacemaker has demonstrated favorable outcomes in global trials, but its real-world performance and safety in a Japan-specific population is unknown.Methods and Results: Micra Acute Performance (MAP) Japan enrolled 300 patients undergoing Micra VR leadless pacemaker implantation in 15 centers. The primary endpoint was the acute (30-day) major complication rate. The 30-day and 6-month major complication rates were compared to global Micra studies. All patients underwent successful implantation with an average follow-up of 7.23±2.83 months. Compared with previous Micra studies, Japanese patients were older, smaller, more frequently female, and had a higher pericardial effusion risk score. 11 acute major complications were reported in 10 patients for an acute complication rate of 3.33% (95% confidence interval: 1.61-6.04%), which was in line with global Micra trials. Pericardial effusion occurred in 4 patients (1.33%; 3 major, 1 minor). No procedure or device-related deaths occurred. Frailty significantly improved from baseline to follow-up as assessed by Japan Cardiovascular Health Study criteria.

CONCLUSIONS

In a Japanese cohort, implantation of the Micra leadless pacemaker had a high success rate and low major complication rate. Despite the Japan cohort being older, smaller, and at higher risk, the safety and performance was in line with global Micra trials.

Leadless epicardial pacing at the left ventricular apex: an animal study

AIMS

State-of-the-art pacemaker implantation technique in infants and small children consists of pace/sense electrodes attached to the epicardium and a pulse generator in the abdominal wall with a significant rate of dysfunction during growth, mostly attributable to lead failure. In order to overcome lead-related problems, feasibility of epicardial implantation of a leadless pacemaker at the left ventricular apex in a growing animal model was studied.

METHODS AND RESULTS

Ten lambs (median body weight 26.8 kg) underwent epicardial implantation of a Micra transcatheter pacing system (TPS) pacemaker (Medtronic Inc., Minneapolis, USA). Using a subxyphoid access, the Micra was introduced through a short, thick-walled tube to increase tissue contact and to prevent tilting from the epicardial surface. The Micra's proprietary delivery system was firmly pressed against the heart, while the Micra was pushed forward out of the sheath allowing the tines to stick into the left ventricular apical epimyocardium. Pacemakers were programmed to VVI 30/min mode. Pacemaker function and integrity was followed for 4 months after implantation. After implantation, median intrinsic R-wave amplitude was 5 mV [interquartile range (IQR) 2.8-7.5], and median pacing impedance was 2235 Ω (IQR 1725-2500), while the median pacing threshold was 2.13 V (IQR 1.25-2.9) at 0.24 ms. During follow-up, 6/10 animals had a significant increase in pacing threshold with loss of capture at maximum output at 0.24 ms in 2/10 animals. After 4 months, median R-wave amplitude had dropped to 2.25 mV (IQR 1.2-3.6), median pacing impedance had decreased to 595 Ω (IQR 575-645), and median pacing threshold had increased to 3.3 V (IQR 1.8-4.5) at 0.24 ms. Explantation of one device revealed deep penetration of the Micra device into the myocardium.

CONCLUSION

Short-term results after epicardial implantation of the Micra TPS at the left ventricular apex in lambs were satisfying. During mid-term follow-up, however, pacing thresholds increased, resulting in loss of capture in 2/10 animals. Penetration of one device into the myocardium was of concern. The concept of epicardial leadless pacing seems very attractive, and the current shape of the Micra TPS makes the device unsuitable for epicardial placement in growing organisms.

Sex differences in leadless pacemaker implantation: A propensity-matched analysis from the i-LEAPER registry

BACKGROUND

The impact of sex in clinical and procedural outcomes in leadless pacemaker (LPM) patients has not yet been investigated.

OBJECTIVE

The purpose of this study was to investigate sex-related differences in patients undergoing LPM implantation.

METHODS

Consecutive patients enrolled in the i-LEAPER registry were analyzed. Comparisons between sexes were performed within the overall cohort using an adjusted analysis with 1:1 propensity matching for age and comorbidities. The primary outcome was the comparison of major complication rates. Sex-related differences regarding electrical performance and all-cause mortality during follow-up were deemed secondary outcomes.

RESULTS

In the overall population (n = 1179 patients; median age 80 years), 64.3% were men. After propensity matching, 738 patients with no significant baseline differences among groups were identified. During median follow-up of 25 [interquartile range 24-39] months, female sex was not associated with LPM-related major complications (hazard ratio [HR] 2.03; 95% confidence interval [CI] 0.70-5.84; P = .190) or all-cause mortality (HR 0.98; 95% CI 0.40-2.42; P = .960). LPM electrical performance results were comparable between groups, except for a higher pacing impedance in women at implant and during follow-up (24 months: 670 [550-800] Ω vs 616 [530-770] Ω; P = .014) that remained within normal limits.

CONCLUSION

In a real-world setting, we found differences in sex-related referral patterns for LPM implantation with an underrepresentation of women, although major complication rate and LPM performance were comparable between sexes. Female patients showed higher impedance values, which had no impact on overall device performance. Electrical parameters remained within normal limits in both groups during the entire follow-up.

Preclinical cardiac perforation reduction in leadless pacing: An update to the Micra leadless pacemaker delivery system

BACKGROUND

Leadless pacemakers have been developed to avoid some of the complications that are associated transvenous pacemakers. Pericardial effusion is a rare complication of leadless pacemaker implantation, which may result from perforation of the delivery catheter. In this study, we describe preclinical perforation performance of an updated Micra delivery catheter.

METHODS

To assess preclinical perforation performance of the updated delivery catheter, three analyses were performed. First, Finite Element Analysis (FEA) computational modeling was performed to estimate the target tissue stress during Micra delivery catheter tenting. Second, benchtop perforation forces of ovine tissue were recorded for the original and updated delivery catheters. Finally, a Monte-Carlo simulation combining human cadaveric Micra implant forces and human ventricular tissue perforation properties was performed to estimate clinical perforation performance.

RESULTS

FEA modeling demonstrated a 66% reduction in target tissue stress when using the updated Micra delivery catheter (6.2 vs. 2.2 psi, Original vs. Updated Micra delivery catheter). Updated Micra delivery catheters required 20% more force to perforate porcine ventricular tissues in benchtop testing (μupd  = 26.9N vs. μorg  = 22.4N, p = .01). Monte-Carlo Simulation of catheter performance in human cadaveric tissues predicts 28.5% reduction of catheter-perforated cases with the updated delivery catheter.

CONCLUSIONS

This study, using computer modelling and benchtop experimentation, has indicated that increased surface area and rounding of the updated Micra catheter tip significantly improves preclinical perforation performance. It will be important to evaluate the impact of these catheter design changes with robust registry data.

Initial studies on the implanting sites of high and low ventricular septa using leadless cardiac pacemakers

OBJECTIVE

To study the safety and electrical characteristics of various implanting sites of the Micra pacemaker.

METHOD

A total of 15 patients from Beijing Anzhen Hospital, Capital Medical University, were included, who were implanted with Micra leadless pacemakers and allocated to either the high ventricular septum group (eight patients) or the low ventricular septum group (seven patients) based on their individual patient factors and clinical conditions. The baseline of the patients, the implanting area, the electrocardiogram change after implantation, the implantation data, the threshold, R wave, impedance, and the date of the 1-month follow-up were then analyzed. With all of the data, the characteristics of different implantation sites of the Micra pacemaker were determined.

RESULTS

Overall, the thresholds were low at implantation and remained stable over the 1-, 3-, 6-month, 1-, 2-, 3-, and 4-year follow-ups. On comparing the two groups, there was no difference in QRS duration at pacing (140.00 [40.00] ms vs. 179.00 [50.00] ms), threshold at implantation (0.38 [0.22] mV vs. 0.63 [1.00] mV), R wave at implantation ([10.85 ± 4.71] V vs. [7.26 ± 2.98] V), or impedance at implantation ([906.25 ± 162.39] Ω vs. [750.00 ± 173.40] Ω). While the difference in QRS duration between the two groups was not significant, the QRS duration of the high ventricular septum group exhibited a reduced tendency compared with that of the low ventricular group. The corrected QT interval during pacing exhibited a significant difference (440.00 [80.00] ms vs. 520.00 [100.00] ms; p < .05). For the 1-, 3-, 6-month, 1-, 2-, 3-, and 4-year follow-ups, there was no difference between the threshold of the high ventricular septum group and that of the low ventricular septum group (p > .05).

CONCLUSION

High ventricular septum pacing appears to be a safe site for implantation of the Micra pacemaker. It could entail a shorter QRS duration at pacing and could be more physiological than low ventricular septum pacing.

Outcomes of leadless pacemaker implantation following transvenous lead extraction in high-volume referral centers: Real-world data from a large international registry

BACKGROUND

Limited data on the real-world safety and efficacy of leadless pacemakers (LPMs) post-transvenous lead extraction (TLE) are available.

OBJECTIVE

The purpose of this study was to assess the long-term safety and effectiveness of LPMs following TLE in comparison with LPMs de novo implantation.

METHODS

Consecutive patients who underwent LPM implantation in 12 European centers joining the International LEAdless PacemakEr Registry were enrolled. The primary end point was the comparison of LPM-related complication rate at implantation and during follow-up (FU) between groups. Differences in electrical performance were deemed secondary outcomes.

RESULTS

Of the 1179 patients enrolled, 15.6% underwent a previous TLE. During a median FU of 33 (interquartile range 24-47) months, LPM-related major complications and all-cause mortality did not differ between groups (TLE group: 1.6% and 5.4% vs de novo group: 2.2% and 7.8%; P = .785 and P = .288, respectively). Pacing threshold (PT) was higher in the TLE group at implantation and during FU, with very high PT (>2 V@0.24 ms) patients being more represented than in the de novo implantation group (5.4% vs 1.6 %; P = .004). When the LPM was deployed at a different right ventricular (RV) location than the one where the previous transvenous RV lead was extracted, a lower proportion of high PT (>1-2 V@0.24 ms) patients at implantation, 1-month FU, and 12-month FU (5.9% vs 18.2%, P = .012; 3.4% vs 12.9%, P = .026; and 4.3% vs 14.5%, P = .037, respectively) was found.

CONCLUSION

LPMs showed a satisfactory safety and efficacy profile after TLE. Better electrical parameters were obtained when LPMs were implanted at a different RV location than the one where the previous transvenous RV lead was extracted.

Leadless pacemaker implantation for pediatric patients through internal jugular vein approach: A case series of under 30 kg

BACKGROUND

We demonstrate a case series of 8 pediatric patients, all under 30 kg, who had leadless pacemaker implants via the internal jugular vein.

METHODS

A retrospective review of pediatric leadless pacing placement via the internal jugular vein at the University of Minnesota Masonic Children's Hospital and UC Davis Medical Center from 2018 through 2021 was performed. Rationales for pacing, demographics of patients, pacing thresholds, and longevity of devices were recorded.

RESULTS

Eight internal jugular pacemaker insertions were performed successfully in patients weighing between 10.9 kg and 29 kg. Five patients had Micra implantation via the right internal jugular vein, whereas 3 patients had insertion via the left internal jugular vein. No surgical cut-downs were performed. No venous complications occurred. Up to 3 years of follow-up were noted.

CONCLUSION

Leadless pacemaker implantation, via left or right internal jugular veins, is feasible without surgical cutdown in patients <30 kg.

Leadless Micra pacemaker implantation in patient with previous Senning procedure for dextro-transposition of the great arteries

Leadless pacemakers have been developed with key advantages over traditional transvenous pacemakers by substantially mitigating the risks of device infection and lead related complications, and providing an alternative pacing strategy in patients with barriers to superior venous access. The Medtronic Micra leadless pacing system is designed for implantation through a femoral venous approach across the tricuspid valve, via Nitinol tine fixation into the trabeculated subpulmonic right ventricle. Patients with surgically corrected dextro-transposition of the great arteries (d-TGA) have an increased risk of pacing requirement. There is limited published experience of implantation of leadless Micra pacemakers in this population, with key challenges relating to trans-baffle access, and deployment of the device into the less trabeculated subpulmonic left ventricle. Here we describe a case report of leadless Micra implantation in a 49 year old male with d-TGA and Senning procedure in childhood, who required pacing for symptomatic sinus node disease, with anatomic barriers to transvenous pacing. Micra implantation was successfully performed following careful consideration of patient anatomy, including the utilisation of 3D modelling to guide the implantation procedure.

Periprocedural anticoagulation therapy in patients undergoing micra leadless pacemaker implantation

Over the past decade, there has been significant improvement in the treatment cardiac diseases and symptomatic bradyarrhythmias with the development of leadless pacemaker systems. The Micra transcatheter pacemaker system has been shown to mitigate a lot of the complications associated with traditional pacing systems, which are notably skin pocket and lead-related complications. Numerous studies have shown the low complication rates associated with Micra procedure; however, there have been no specific guidelines or recommendations surrounding periprocedural anticoagulant therapy. This is important because a significant percentage of patients requiring pacemaker therapy have an indication for anticoagulation therapy as well. Multiple studies have shown the safety of uninterrupted anticoagulation during Micra implant, however, there is insufficient high-quality data to recommend periprocedural systemic use of anticoagulation. In this paper, we review the available data surrounding anticoagulation therapy in patients undergoing Micra implantation and the potential bleeding risks associated with this procedure.

A leadless pacemaker in the real-world setting: Patient profile and performance over time

Background

While prior Micra trials demonstrated a high implant success rate and favorable safety and efficacy results, changes in implant populations and safety over time is not well studied. The objective of this analysis was to report the performance of Micra in European and Middle Eastern patients and compare to the Micra Investigational Device Exemption (IDE) and Micra Post Approval Registry (PAR) studies.

Methods

The prospective, single-arm Micra Acute Performance European and Middle Eastern (MAP EMEA) registry was designed to further study the performance of Micra in patients from EMEA. The primary endpoint was to characterize acute (30-day) major complications. Electrical performance was analyzed. The major complication rate through 12 months was compared with the IDE and PAR studies.

Results

The MAP EMEA cohort (n = 928 patients) had an implant success rate of 99.9% and were followed for an average of 9.7 ± 6.5 months. Compared to prior studies, MAP EMEA patients were more likely to have undergone dialysis and have a condition which precluded the use of a transvenous pacemaker (p < .001). Within 30 days of implantation, the MAP EMEA cohort had a major complication rate of 2.59%. Mean pacing thresholds were low and stable through 12 months (0.61 ± 0.40 V at 0.24 ms at implant and 12 months). Through 12 months post-implantation, the major complication rate for MAP EMEA was not significantly different from IDE (p = .56) or PAR (p = .79).

Conclusion

Despite patient differences over time, the Micra leadless pacemaker was implanted with a high success rate and low complication rate, in-line with prior reports.

The subtle tine: Asymptomatic Micra perforation incidentally discovered during cardiac surgery

A 70-year-old woman with longstanding persistent atrial fibrillation underwent Micra leadless pacemaker implantation and atrioventricular nodal ablation. No postprocedural complications were noted. She subsequently underwent surgical mitral valve replacement 4 years later. During the surgery, Micra tine perforation of the right ventricular free wall was seen. No device revision was performed due to her asymptomatic status and stable pacemaker position/function. Pericardial effusion is a known complication of Micra implantation. The incidence of tine perforation is unknown as many patients may be asymptomatic. The clinical consequences regarding adverse events, device functionality, and explantation/extraction risk profile remain to be determined.

Leadless pacemaker implantation in dextrocardia with situs viscerum inversus: A case report and literature review

Leadless pacemaker implantation (LPI) has fewer device complications and reduced chance of infection compared to conventional pacemakers. Dextrocardia with situs viscerum inversus (DC+SVI) is a rare condition, which seldom leads to cardiac complications. However, its presence poses a challenge to operators in cardiac procedures. LPI reports in DC patients are scarce. We report a case of LPI in a DC+SVI patient, followed by a brief but comprehensive literature review.

Percutaneous aspiration and removal of infected leadless pacemaker vegetation

INTRODUCTION

Leadless pacemakers represent an increasingly utilized alternative to traditional pacing methods in those with prior bacteremia or at high risk for infection. The acknowledged resistance to infection is illustrated by the exceedingly rare documentation of it.

METHODS

We present a case of methicillin-sensitive Staphylococcus aureus endocarditis with associated leadless pacemaker infection necessitating percutaneous aspiration of the device-associated vegetation followed by extraction of the leadless pacemaker.

RESULTS

Large vegetation associated with a leadless pacemaker was percutaneously aspirated with a vacuum-assisted aspiration device, followed by successful extraction of the leadless pacemaker.

CONCLUSION

While leadless pacemakers are seldom involved in infective endocarditis, ultrasound evaluation in high-risk patients with an undetermined source is reasonable. Before extraction, it is practical to consider aspiration of large associated vegetations with a vacuum-assisted device.

The angle of the tines before the pull and hold test predicts engagement of the tines in Micra leadless pacemaker implantation

Background

Micra leadless pacemaker is secured to the myocardium by engagement of at least 2/4 tines confirmed with pull and hold test. However, the pull and hold test is sometimes difficult to assess. This study was performed to evaluate whether the angle of the tines before the pull and hold test predicts engagement of the tines in Micra leadless pacemaker implantation.

Methods

We retrospectively enrolled 93 consecutive patients (52.7% male, age 82.4 ± 9.4 years), who received Micra implantation from September 2017 to June 2020 at our institution. After deployment and before the pull and hold test, the angle of the visible tines to the body of the pacemaker was measured using the RAO view of the fluoroscopy image. The engagement of the tines was then confirmed with the pull and hold test.

Results

A total of 326 tines were analyzed. The angle of the engaged tines was significantly lower than the non-engaged tines (9.2 degrees [4.0-14.0] vs. 16.6 degrees [14.2-18.8], p < .0001). All tines with angles <10 degrees were engaged. In higher angles, engagement could not be predicted.

Conclusion

A low angle of the tines before the pull and hold test can predict engagement of the tines in Micra leadless pacemaker implantation. The tines which are already open after deployment may be presumed that they are engaged.

Visual observation of extraction of a Micra leadless pacemaker from a human cadaver

INTRODUCTION

In this article we present the extraction of a Micra from a human cadaver implanted 3 years previously with both visual and X-ray imaging taken during the removal.

METHODS

A Micra pacemaker was extracted from a human cadaver with endoscopy and fluoroscopy using a Micra delivery tool. Histological analysis was performed on slices from the tissue surrounding the Micra.

RESULTS

The fully encapsulated Micra was easily retrieved with a maximum force of 1.9 pounds.

CONCLUSIONS

Even though the Micra was implanted almost 3 years previously, the snaring and extraction of the Micra was performed relatively easily and with minimal force required.

Pediatric Micra leadless pacemaker implantation via internal jugular and femoral veins: experience with 11 patients

In pediatrics, conventional transvenous and epicardial pacemaker systems carry complications, such as lead distortion due to growth and activity, in addition to lead and pocket complications. A retrospective review of pediatric leadless pacing at the University of Minnesota Masonic Children's Hospital (MN, USA) from 2018 through 2021 was performed. Diagnoses, rationale for pacing, demographics, pacing thresholds and longevity of devices were recorded. Twelve leadless pacemaker insertions and one removal were performed successfully in patients weighing 19-90 kg. Six patients had Micra implantation via the internal jugular vein without surgical cut-down. Up to 3 years of follow-up were noted, with median follow-up of 22 months. No late complications occurred. Leadless pacemaker implantation and early retrieval were feasible in pediatric patients.

Leadless Pacing: Where We Currently Stand and What the Future Holds

PURPOSE OF REVIEW

Leadless pacemakers (LPs) are emerging as alternative cardiac implantable devices for the treatment of bradyarrhythmia. This article aims to review the data behind the safety and efficacy of these devices while highlighting their pros and cons.

RECENT FINDINGS

Prospective non-randomized studies and registries have found that LPs are associated with lower rate of device-related complications mainly driven by lower need for lead-related interventions as compared to traditional pacemakers. On the other hand, cardiac perforation appears to occur more frequently with LPs. LPs are associated with lower rate of device-related complications as compared to the traditional pacemakers. However, the rate of pericardial effusion is higher and is more severe. As we transition to multi-chamber LPs, it is important to ensure the safety and efficacy of these devices.

Leadless Pacemaker in Twiddler's Syndrome: A Case Report

Twiddler's syndrome is a rare cause of pacemaker lead dislodgement. We present the case of a 49-year-old male patient with Down's syndrome implanted with a dual chamber pacemaker showing high ventricular impedance, no sensing, and complete loss of capture for both leads at the 3-month follow-up due to Twiddler Syndrome. The dislocated device was removed, and an endocardial leadless pacing system was implanted. This article is protected by copyright. All rights reserved.

Evolution of tricuspid valve regurgitation after implantation of a leadless pacemaker - a single center experience, systematic review and meta-analysis

Introduction

Conventional transvenous pacemaker leads may interfere with the tricuspid valve leaflets, tendinous chords, and papillary muscles, resulting in significant tricuspid valve regurgitation (TR). Leadless pacemakers (LLPMs) theoretically cause less mechanical interference with the tricuspid valve apparatus. However, data on TR after LLPM implantation are sparse and conflicting. Our goal was to investigate the prevalence of significant TR before and after LLPM implantation.

Methods

Patients who received a leadless LLPM (Micra™ TPS, Medtronic) between May 2016 and May 2021 at our center were included in this observational study if they had at least a pre‐ and postinterventional echocardiogram (TTE). The evolution of TR severity was assessed. Following a systematic literature review on TR evolution after implantation of a LLPM, data were pooled in a random‐effects meta‐analysis.

Results

We included 69 patients (median age 78 years [interquartile range (IQR) 72–84 years], 26% women). Follow‐up duration between baseline and follow‐up TTE was 11.4 months (IQR 3.5–20.1 months). At follow‐up, overall TR severity was not different compared to baseline (p = .49). Six patients (9%) had new significant TR during follow‐up after LLPM implantation, whereas TR severity improved in seven patients (10%). In the systematic review, we identified seven additional articles that investigated the prevalence of significant TR after LLPM implantation. The meta‐analysis based on 297 patients failed to show a difference in significant TR before and after LLPM implantation (risk ratio 1.22, 95% confidence interval 0.97–1.53, p = .11).

Conclusion

To date, there is no substantial evidence for a significant change in TR after implantation of a LLPM.

Leadless atrio-ventricular synchronous pacing in an outpatient setting - early lessons learned on factors affecting atrio-ventricular synchrony

BACKGROUND

Leadless pacemakers (PMs) capable of atrio-ventricular (AV) synchronous pacing have recently been introduced. Initial feasibility studies were promising, but limited to just a few minutes of AV synchronous pacing. Real-world long-term data on AV synchrony and programming adjustments affecting AV synchrony in outpatients are lacking.

OBJECTIVE

To investigate AV synchrony and influences of PM programming adjustments in outpatients with leadless VDD PMs.

METHODS

All patients who received a leadless VDD PM (Micra™ AV, Medtronic, US) between 07/2020 and 05/2021 at our center were included in this observational study. AV synchrony was assessed repeatedly postoperatively and during follow-up using Holter ECG recordings. AV synchrony was defined as a QRS complex preceded by a p-wave within 300ms. The impact of programming changes during follow-up on AV synchrony was studied.

RESULTS

816 hours of Holter ECG from 20 outpatients were analyzed. During predominantly paced episodes (≥80% ventricular pacing), median AV synchrony was 91% (IQR 34-100%) when patients had sinus rates 50-80/min. Median AV synchrony was lower when patients had sinus rates >80/min (33%, IQR 29-46%, p<0.001). During a stepwise optimization protocol, AV synchrony could be improved (p<0.038). Multivariate analysis showed that a shorter maximum A3 window end (p<0.001), a lower A3 threshold (p=0.046), and minimum A4 threshold (p<0.001) improved AV synchrony.

CONCLUSION

Successful VDD pacing in the outpatient setting during higher sinus rates is more difficult to achieve than can be presumed based on the initial feasibility studies. The devices often require multiple reprogramming to maximize AV sequential pacing.

Ventricular Fibrillation Cardiopulmonary Arrest Following Micra™ Leadless Pacemaker Implantation

Leadless cardiac pacemakers such as the Micra™ transcatheter leadless pacing system (Medtronic, Minneapolis, MN, USA) are an alternative to traditional transvenous pacemakers. Implantation of leadless pacemakers, albeit safe, may be associated with complications, including cardiac tamponade; high capture thresholds; and, rarely, ventricular arrhythmias. We report a case of ventricular fibrillation arrest following the implantation of a Micra™ leadless pacemaker.

Leadless pacemakers: A review of current data and future directions

Leadless pacemakers (LPs) have revolutionized the field of pacing by miniaturizing pacemakers and rendering them completelty intracardiac, hence reducing complications related to pacemaker pockets and transvenous leads. However, first generation LPs appear to be associated with a higher rate of myocardial perforation as compared to transvenous pacemakers (TV-PPM). Currently, LPs are predominantly designed to pace the right ventricle with no LPs that provide atrial or biventricular pacing. In this article, we review the available data on LPs while advocating for the need for a randomized controlled trial comparing LPs to TV-PPMs. In addition, we review the future directions of leadless devices.

The Large Right Heart Is Associated with the Prolongation of the Procedure Time of Leadless Pacemaker Implantation

Background and objectives: Leadless pacemakers are less invasive but are as effective as conventional pacemakers and are increasingly implanted in elderly patients. However, the implantation procedure is sometimes challenging in patients with abnormal anatomy, particularly those with an enlarged right heart. We aimed to determine the right heart parameters that were associated with longer procedure times for leadless pacemaker implantation. Materials and Methods: Among 19 consecutive patients in whom Micra leadless pacemakers (Micra TPS, Medtronic, Minneapolis, MN) were implanted, the diameter and area of both the right atrium and right ventricle were measured by transthoracic echocardiography before the procedure. The right heart parameters that were associated with a procedure time > 60 min were investigated. Results: In the 19 patients (median 81 years old, 10 male) who underwent implantation of the Micra system, 6 (32%) required a procedure time > 60 min. Among the baseline right heart echocardiographic parameters, right atrial diameter and area were significantly associated with a procedure time > 60 min (odds ratio 11.3, 95% confidence interval 1.09-1.17, p = 0.042; and odds ratio 1.57, 95% confidence interval 1.05-2.34, p = 0.029, respectively) at a cutoff of 4.0 cm and 17.0 cm2, respectively. Conclusions: Patients with an enlarged right atrium may not be good candidates for leadless pacemakers given the longer procedure time, and conventional pacemakers should perhaps be recommended as an alternative.

Native joint infections caused by Parvimonas micra

Parvimonas micra is an anaerobic, fastidious, gram positive organism commonly found in the oral cavity and gastrointestinal tract. It has been increasingly reported as the cause of septic arthritis of native joints, often times with delayed diagnosis leading to increased morbidity. Risk factors include immunosuppression, inflammation of the joint, and recent dental procedures or infections. It has been a historically difficult organism to culture. However, the development of and increasing use of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has led to increased identification of P. micra. Common antibiotic susceptibilities, as well as data regarding susceptibilities in specific situations, have been reported, but susceptibility testing is required in all cases. Common treatments include clindamycin, penicillin, and metronidazole for six to ten weeks.

Leadless pacemaker implantation quality: importance of the operator's experience

AIMS

Leadless cardiac pacemaker (PM) implantation differs from conventional PM implantation. While the procedure has been considered safe, recent real-world data raised concerns about the learning curve of new operators and their implantation quality. The goal of this study was to investigate the influence of the first operator's experience on leadless PM implantation quality and procedural efficiency.

METHODS AND RESULTS

We performed a bicentric analysis of all Micra TPS™ implantations in two large tertiary referral hospitals. We assessed both leadless PM implantation quality based on the absence of complications (requiring intervention or prolonged hospitalization), good electrical performance (pacing threshold ≤ 1.5 V/0.24 ms, R-wave amplitude > 5 mV), and acceptable fluoroscopy duration (<10 min) as well as procedural efficiency in relation to the operator's experience. Univariate and multivariate logistic regression analyses were performed to identify predictors for implantation quality and procedural efficiency. Leadless PM implantation was successful in 106/111 cases (95.5%). Three patients (2.7%) experienced acute complications (one cardiac tamponade, one femoral bleeding, one posture-related PM exit block). Multivariate analysis showed that implantation quality of more experienced first operators was higher [odds ratio 1.09 (95% confidence interval 1.00-1.19), P = 0.05]. Procedural efficiency increased with operator experience as evidenced by an inverse correlation of procedure time, time to the first deployment, fluoroscopy time, and the number of procedures performed (all P < 0.05).

CONCLUSION

The operator's learning curve is a critical factor for leadless PM implantation quality and procedural efficiency.

Tortuous inferior vena cava with severe scoliosis: An impediment to successful leadless pacemaker implantation

Both a multicenter cohort and a post-approval registry of the Micra™ transcatheter pacemaker (Medtronic, Minneapolis, MN, USA) reported high successful implantation rates (>99%) with long-term stability of electrical performance and long-term safety. Therefore, there has been little discussion on the causes of cases of failure in terms of anatomical findings. We report a case of failure of implantation of the Micra because of a tortuous inferior vena cava (IVC) secondary to severe scoliosis. A retrospective assessment of 3D reconstructed computed tomography imaging could visualize the configuration of the IVC-right atrium junction. A preprocedural anatomical assessment may help to predict the implantability of the transcatheter leadless pacemaker or to image the manipulation of the delivery catheter. <Learning objective: The Micra™ leadless pacemaker had high successful implantation rates (>99%). There has been little discussion on the causes of cases of failure in terms of anatomical findings. We report a case of failure of implantation of the Micra device because of a tortuous inferior vena cava secondary to severe scoliosis. A preprocedural 3D reconstructed computed tomography may help to predict the procedural difficulty of the Micra implantation or to image a manipulation of the delivery catheter.>.

TTE guided synchronization to optimize AV synchronous leadless pacemaker programming

Transvenous pacemakers are associated with major complications [1]. Transcatheter leadless pacemaker has reduced the incidence of these complications and the recent accelerometer based atrial sensing algorithm permits restoration of atrioventricular synchrony [1]. We report utilizing cardiac output measurements using Transthoracic Echocardiography (TTE) to determine optimal programming for leadless pacemaker.

Nontransvenous Cardiovascular Implantable Electronic Device Technology-A Review for the Anesthesiologist

There has been a recent shift in bradycardia pacing and defibrillation therapy to leadless pacemakers and extrathoracic cardioverter-defibrillator technology due to complications associated with transvenous devices. These innovations have implications for anesthesia care, as these novel devices have design and functionality features different from transvenous devices. Current perioperative guidelines do not address management of leadless pacemakers and the subcutaneous implantable cardioverter-defibrillator, although implantation rates are increasing globally. This article addresses the features and capabilities of nontransvenous cardiac implantable electronic devices, such as the Micra and the subcutaneous implantable cardioverter-defibrillator, and provides guidance for perioperative management.

Micra™ Leadless Intracardiac Pacemaker Implantation: A Safer Option During the Coronavirus Disease 2019 Pandemic

The Micra™ Transcatheter Pacing System (Medtronic, Minneapolis, MN, USA) is a fairly novel leadless intracardiac pacemaker implanted in the right ventricle via a femoral-vein transcatheter approach. Due to the less-invasive nature of the implantation procedure and its smaller size, patients receiving the Micra™ device tend to experience fewer complications, hospitalizations, and revisions when compared with those with transvenous pacemakers. Certain arrhythmias and conduction abnormalities, such as high-degree atrioventricular blocks, require urgent and timely pacemaker insertion—a necessity that has persisted even during the coronavirus disease 2019 (COVID-19) pandemic. Here, we present a case series of 10 patients with various conduction disease abnormalities who required right ventricle pacemaker implantation during the months of March to May 2020, which was the initial peak of the COVID-19 pandemic in New Jersey, including the enhanced precautions taken to avoid viral spread.

Leadless pacemaker implant with concomitant atrioventricular node ablation: Experience with the Micra transcatheter pacemaker

Background

The feasibility and outcomes of concomitant atrioventricular node ablation (AVNA) and leadless pacemaker implant are not well studied. We report outcomes in patients undergoing Micra implant with concomitant AVNA.

Methods

Patients undergoing AVNA at the time of Micra implant from the Micra Transcatheter Pacing (IDE) Study, Continued Access (CA) study, and Post‐Approval Registry (PAR) were included in the analysis and compared to Micra patients without AVNA. Baseline characteristics, acute and follow‐up outcomes, and electrical performance were compared between patients with and without AVNA during the follow‐up period.

Results

A total of 192 patients (mean age 77.4 ± 8.9 years, 72% female) underwent AVNA at the time of Micra implant and were followed for 20.4 ± 15.6 months. AVNA patients were older, more frequently female, and tended to have more co‐morbid conditions compared with non‐AVNA patients (N = 2616). Implant was successful in 191 of 192 patients (99.5%). The mean pacing threshold at implant was 0.58 ± 0.35 V and remained stable during follow‐up. Major complications within 30 days occurred more frequently in AVNA patients than non‐AVNA patients (7.3% vs. 2.0%, p < .001). The risk of major complications through 36‐months was higher in AVNA patients (hazard ratio: 3.81, 95% confidence interval: 2.33–6.23, p < .001). Intermittent loss of capture occurred in three AVNA patients (1.6%), all were within 30 days of implant and required system revision. There were no device macrodislodgements or unexpected device malfunctions.

Conclusion

Concomitant AVN ablation and leadless pacemaker implant is feasible. Pacing thresholds are stable over time. However, patient comorbidities and the risk of major complications are higher in patients undergoing AVNA.

Pediatric Micra leadless pacemaker implantation via internal jugular and femoral vein: a single center, US experience

Background: In the pediatric population, conventional transvenous and epicardial pacemaker systems carry complications such as lead distortion due to growth/activity, in addition to other lead/pocket complications. Materials & methods: A retrospective review of pediatric leadless pacing at the University of Minnesota Masonic Children's Hospital from 2018 to 2020 was performed. Rationale for pacing, demographics of patients, thresholds and longevity of devices were recorded. Results: Seven leadless pacemaker insertions and one removal were performed successfully, in patients weighing between 19 kg and 58 kg. Three patients had Micra implantation via internal jugular vein. One pericardial effusion occurred perioperatively in a 19 kg patient with baseline thrombocytopenia, sideroblastic anemia and Pearson Marrow Pancreas syndrome. Conclusion: Leadless pacemaker implantation/early retrieval is feasible in pediatric patients.

Life cycle management of Micra transcatheter pacing system: Data from a high-volume center

BACKGROUND

Data on the management of Micra transcatheter pacing system (TPS) at the time of an upgrade or during battery depletion is limited.

OBJECTIVE

We sought to evaluate the management patterns of patients implanted with a Micra TPS during long-term follow-up.

METHODS

We retrospectively identified patients who underwent Micra implantation from April 2014 to November 2019. We identified patients who underwent extraction (n = 11) or had an abandoned Micra (n = 12).

RESULTS

We identified 302 patients who received a Micra during the period of the study. Mean age was 72.7 ± 15.4 years, 54.6% were men, and left ventricular ejection fraction was 51.9 ± 5.2%. Mean follow-up was 1105.5 ± 529.3 days. Procedural complications included pericardial tamponade (n = 1) treated with pericardiocentesis, significant rise in thresholds (n = 6) treated with reimplantation (n = 4), and major groin complications (n = 2). Indications for extraction included an upgrade to cardiac resynchronization therapy (CRT) device (n = 3), bridging after extraction of an infected transvenous system (n = 3), elevated thresholds (n = 3), and non-Micra-related bacteremia (n = 2). The median time from implantation to extraction was 78 days (interquartile range: 14-113 days), with the longest extraction occurring at 1442 days. All extractions were successful, with no procedural or long-term complications. Indications for abandonment included the need for CRT (n = 6), battery depletion (n = 2), increasing thresholds/failure to capture (n = 3), and pacemaker syndrome (n = 1). All procedures were successful, with no procedural or long-term complications.

CONCLUSION

In this large single-center study, 6% of patients implanted with a Micra required a system modification during long-term follow-up, most commonly due to the requirement for CRT pacing. These patients were managed successfully with extraction or abandonment.

Atrio-ventricular synchronous pacing with a single chamber leadless pacemaker: Programming and trouble shooting for common clinical scenarios

Micra leadless pacemaker has progressed from a single chamber pacemaker that can deliver VVIR pacing to a pacing device that can provide atrio‐ventricular (AV) synchrony via a unique pacing algorithm that relies on identifying mechanical atrial contraction. This novel algorithm has its own limitations and intricacies. In this paper, we review this algorithm, suggest steps for troubleshooting and programming these devices and provide clinical examples of Micra AV cases that required changes in programming for adequate tracking of atrial activity.