Ambulatory atrioventricular synchronous pacing over time using a leadless ventricular pacemaker: Primary results from the AccelAV study

BACKGROUND

Previous studies demonstrated that accelerometer-based, mechanically timed atrioventricular synchrony (AVS) is feasible using a leadless ventricular pacemaker.

OBJECTIVE

The purpose of this study was to determine the performance of a leadless ventricular pacemaker with accelerometer-based algorithms that provide AVS pacing.

METHODS

AccelAV was a prospective, single-arm study to characterize AVS in patients implanted with a Micra AV, which uses the device accelerometer to mechanically detect atrial contractions and promote VDD pacing. The primary objective was to characterize resting AVS at 1 month in patients with complete atrioventricular block (AVB) and normal sinus function.

RESULTS

A total of 152 patients (age 77 ± 11 years; 48% female) from 20 centers were enrolled and implanted with a leadless pacemaker. Among patients with normal sinus function and complete AVB (n = 54), mean resting AVS was 85.4% at 1 month, and ambulatory AVS was 74.8%. In the subset of patients (n = 20) with programming optimization, mean ambulatory AVS was 82.6%, representing a 10.5% improvement (P <.001). Quality of life as measured by the EQ-5D-3L (EuroQol Five-Dimensions Three-Level questionnaire) improved significantly from preimplant to 3 months (P = .031). In 37 patients with AVB at both 1 and 3 months, mean AVS during rest did not differ (86.1% vs 84.1%; P = .43). There were no upgrades to dual-chamber devices or cardiac resynchronization therapy through 3 months.

CONCLUSION

Accelerometer-based mechanical atrial sensing provided by a leadless pacemaker implanted in the right ventricle significantly improves quality of life in a select cohort of patients with AV block and normal sinus function. AVS remained stable through 3 months, and there were no system upgrades to dual-chamber pacemakers.

[Approach to patients with Assurity® and Endurity® pacemakers : Recommendations from the nucleus of the Working Group Electrophysiology and Rhythmology of the German Cardiac Society]

In a subset of patients with pacemaker models Assurity® and Endurity® (Abbott, Sylmar, California, USA; worldwide outside the USA approximately 83,000 devices), a mistake during production may have occurred resulting in insufficient adhesion between the pulse generator header and device housing which in turn may allow moisture to enter the header. This may cause loss of telemetry, switch to back-up mode, reduced battery longevity, or in worst case loss of pacing. Until June 2022, these malfunctions were reported for 128 devices worldwide (0.15%); no permanent harm to patients due to this issue has been reported. The nucleus of the AGEP suggests the following recommendations: (1) Patients with a device under safety advisory should be informed. (2) The risks for the patient in case of loss of stimulation should be assessed. Patients should be categorized into "likely pacemaker-dependent" (e.g., indication permanent atrioventricular [AV] block, no intrinsic rhythm at the last follow-up, percentage of ventricular pacing in the device memory > 90%), "unknown", or "likely not pacemaker-dependent" (e.g., indication sick sinus syndrome, intrinsic rhythm > 50 bpm at the last follow-up, percentage of ventricular pacing in the device memory < 1%). (3) In likely pacemaker-non-dependent patients, information about this issue should be provided together with an unchanged follow-up or a follow-up with shortened intervals (e.g., every 3 months) and/or remote monitoring. (4) In patients with unknown risk if stimulation failure occurs, at least follow-up intervals should be shortened to, for example, 3 months and/or remote monitoring should be initialized. In addition, risks and benefits of a device exchange should be weighed against each other. (5) In patients who are likely pacemaker-dependent, device exchange is recommended.

The implantation of AV leadless pacemaker - a case report

In early 2020 Food and Drug Administration (FDA) approved Micra AV - a new type of leadless pacemaker with atrioventricular synchrony, to treat patients with atrio-ventricular (AV) blocks. We describe one of the first in Poland case of a patient who was implanted with Micra AV pacemaker.

CASE REPORT

A 38-year-old female patient was admitted to the clinic due to the 29-seconds event of a complete AV block without an escape rhythm and was implanted with a dual chamber pacemaker without any complications. After several months she was admitted again with suspicion of ventricular perforation by the pacemaker electrode and underwent a replacement procedure of both pacemaker's leads. Nevertheless, one week later the patient developed a fever with significantly elevated inflammatory markers. The blood cultures were negative but in the transesophageal echocardiography features of cardiac device-related infective endocarditis were observed. Empirical antibiotic therapy was administered, and the device was removed. The Heart Team qualified the patient for the implantation of a MicraTM AV leadless pacemaker. The procedure was performed without any complications and the device was implanted to the right ventricle. All parameters were correct, and the patient was discharged.

CONCLUSIONS

Micra AV may be a feasible and safe option for young patients with paroxysmal AV block after device-related complications.

Heart rate distribution in dogs with third degree atrioventricular block and rate responsive pacemakers

INTRODUCTION

In dogs, single lead ventricular pacing, ventricular sensing, inhibition response, rate adaptive (VVIR) pacemakers are routinely used to treat third degree atrioventricular block. The objectives of this study were to investigate the heart rate distribution in dogs with VVIR pacemakers, and report changes when activity settings were adjusted.

ANIMALS

Eighteen client-owned dogs with VVIR pacemakers for third degree atrioventricular block.

MATERIALS AND METHODS

This observational study consisted of a review of medical records of dogs with VVIR pacemakers. For dogs with >50% of paced beats at the lower pacing rate, the activity daily living (ADL) and exertion responses were increased. Re-evaluations were performed after 6-12 months.

RESULTS

Heart rate distribution similar to healthy dogs was absent for all dogs. In nine dogs, the ADL and exertion responses were increased to the highest level. Of these, three dogs showed no improvement in heart rate distribution; for two dogs, one with an epicardial pacemaker, several activity settings were adjusted and pacing at higher heart rates was observed at re-evaluation. Four dogs died or were lost to follow-up. Clinical signs had resolved for all dogs after pacemaker implantation.

CONCLUSION

Default activity settings of VVIR pacemakers do not result in heart rate distribution equivalent to healthy dogs. Increasing the ADL and exertion response settings to the highest levels did not improve the pacemaker rate response. Further investigations into the role of dog size, generator positioning, pacemaker settings, and whether rate responsiveness is required for dogs' quality and quantity of life are warranted.

Acute Q Fever with Atrioventricular Block, Israel

Cardiac involvement in acute Q fever is rare. We report 2 cases of an advanced atrioventricular block in young adult patients in Israel who sought care for acute Q fever without evidence of myocarditis. Q fever should be suspected in unexplained conduction abnormalities, especially in febrile young patients residing in disease-endemic areas.

Acute echocardiographic and hemodynamic response to his-bundle pacing in patients with first-degree atrioventricular block

BACKGROUND

Atrial pacing and right ventricular (RV) pacing are both associated with adverse outcomes among patients with first-degree atrioventricular block (1°AVB). His-bundle pacing (HBP) provides physiological activation of the ventricle and may be able to improve both atrioventricular (AV) and inter-ventricular synchrony in 1°AVB patients. This study evaluates the acute echocardiographic and hemodynamic effects of atrial, atrial-His-bundle sequential (AH), and atrial-ventricular (AV) sequential pacing in 1°AVB patients.

METHODS

Patients with 1°AVB undergoing atrial fibrillation ablation were included. Following left atrial (LA) catheterization, patients underwent atrial, AH- and AV-sequential pacing. LA/left ventricular (LV) pressure and echocardiographic measurements during the pacing protocols were compared.

RESULTS

Thirteen patients with 1°AVB (mean PR 221 ± 26 ms) were included. The PR interval was prolonged with atrial pacing compared to baseline (275 ± 73 ms, p = .005). LV ejection fraction (LVEF) was highest during atrial pacing (62 ± 11%), intermediate with AH-sequential pacing (59 ± 7%), and lowest with AV-sequential pacing (57 ± 12%) though these differences were not statistically significant. No significant differences were found in LA or LV mean pressures or LV dP/dT. LA and LV volumes, isovolumetric times, electromechanical delays, and global longitudinal strains were similar across pacing protocols.

CONCLUSION

Despite pronounced PR prolongation, the acute effects of atrial pacing were not significantly different than AH- or AV-sequential pacing. Normalizing atrioventricular and/or inter-ventricular dyssynchrony did not result in acute improvements in cardiac output or loading conditions.

[The success rate of His-Purkinje system pacing in patients with various sites of atrioventricular block]

Objective: To evaluate the success rate of His-Purkinje system pacing (HPSP) in patients with various sites of atrioventricular block (AVB) and provide clinical evidence for the selection of HPSP in patients with AVB. Methods: This is a retrospective case analysis. 637 patients with AVB who underwent permanent cardiac pacemaker implantation and requiring high proportion of ventricular pacing from March 2016 to September 2021 in the Department of Cardiology, General Hospital of Northern Theater Command were enrolled. The site of AVB was determined by electrophysiological examination. His bundle pacing (HBP) was performed in the first 130 patients (20.4%) who were classified as the HBP group and HPSP included HBP and/or left bundle branch pacing (LBBP) was performed in later 507 patients (79.6%) and these patients were classified as the HPSP group. The basic clinical information such as age and sex of the two groups was compared, and the success rates of HBP or HPSP in patients with different sites of AVB and QRS intervals were analyzed. Results: The age of HBP group was (66.4±15.9) years with 75 males (57.7%). The age of HPSP group was (66.8±13.6) years with 288 (56.8%) males. Among 637 patients, 63.0% (401/637) had atrioventricular node block; 22.9% (146/637) had intra-His block; 14.1% (90/637) had distal or inferior His bundle block. Totally, the success rate of HPSP was higher than that of HBP [93.9% (476/507) vs. 86.9% (113/130), P<0.05]. In each group of patients with various AVB sites, the success rate of HPSP was higher than that of HBP respectively and both success rates of HBP and HPSP showed a declining trend with the distant AVB site. The success rate of HBP in patients with atrioventricular node block and intra-His block was higher than that in patients with distal or inferior His bundle block [95.2% (79/83) vs. 47.1% (8/17), P<0.001; 86.7% (26/30) vs. 47.1% (8/17), P=0.010]. The success rate of HPSP was higher than that of HBP in patients with distal or inferior His bundle block [87.7% (64/73) vs 47.1% (8/17), P=0.001]. In patients with QRS<120 ms, 94.9% (520/548) of AVB sites were in atrioventricular node or intra-His, and HBP had a similar high success rate with HPSP [95.6% (109/114) vs. 96.3% (418/434), P=0.943] in these patients. In patients with QRS ≥ 120 ms, 69.7% (62/89) of AVB sites were at distal or inferior His bundle, and the success rate of HBP was only 25.0% (4/16), while the success rate of HPSP was as high as 79.5% (58/73), P<0.001. Conclusions: In patients with QRS<120 ms and atrioventricular node block or intra-His block, success rates of HBP and HPSP are similarly high and HBP might be considered as the first choice. In patients with QRS ≥ 120 ms and AVB site at distal or inferior His bundle, the success rate of HPSP is higher than that of HBP, suggesting LBBP should be considered as the first-line treatment option.

Leadless Pacemaker Implantation for a Super-elderly Woman with a Mediastinal Tumor

A 95-year-old woman with no cardiac history presented with symptomatic complete atrioventricular block. She underwent temporary cardiac pacing via the cervical vein, but a pacing lead could not be introduced via the usual route because of a mediastinal tumor. A leadless pacemaker (Micra™; Medtronic, Minneapolis, USA) was implanted at the right ventricular septum via the right femoral vein. The procedure time was 40 minutes, with no complications noted. Over the two-year follow-up period, the threshold and impedance remained stable. The implantation of a leadless pacemaker was useful for improving the symptoms of a super-elderly woman with a mediastinal tumor.

The curious case of missing heartbeats

Paroxysmal atrioventricular block (AVB) is a poorly defined and easily missed bradyarrhythmia, which can potentially lead to sudden cardiac death. It is under-recognised due to its abrupt onset and unpredictability. We describe a case that had paroxysmal AVB post-coronary angioplasty and highlight the mechanism as well as the management of this rare condition.

A case of complete atrioventricular block associated with primary cardiac lymphoma reversed without cardiac pacemaker implantation

Primary cardiac lymphoma (PCL) is a rare malignant lymphoma that is characteristically confined to the heart and/or pericardium. Here, the case of a 70-year-old male patient with complete atrioventricular block (AVB) associated with PCL is presented. The patient had a 10-month history of palpitation and electrocardiogram (ECG) showed a complete AVB. Additionally, transthoracic echocardiography indicated pericardial effusion where atypical lymphoid cells were identified by pericardiocentesis. Subsequent mediastinal lymph node biopsy revealed non-germinal centre diffuse large B-cell lymphoma. Therefore, a diagnosis of PCL was confirmed. As the patient’s vital signs were stable, he was prescribed chemotherapy without pacemaker implantation. After chemotherapy, the patient achieved remission and dynamic ECG demonstrated no recurrence of AVB. The present case demonstrates that although PCL initially manifesting as complete AVB is rare, this possibility should not be ignored when a new AVB without definite aetiology is encountered. In addition, if the vital signs of the patient are stable, pacemaker implantation may be postponed until the treatment effect of chemotherapy has been assessed.

Sjogren syndrome presenting as atrioventricular block in an adult

A woman in her late teens with a history of Juvenile idiopathic arthritis (JIA) and ongoing sicca symptoms presented with syncope. Upon admission, she was found to be bradycardic with a second-degree atrioventricular (AV) block. After infectious, structural and metabolic aetiologies had been ruled out, she was worked up for rheumatologic causes.Our patient had elevated titres of anti-Sjogren syndrome (SS) antibodies anti-Ro antibodies and was diagnosed with AV block secondary to SS. She was treated with a permanent pacemaker. Patient was followed up in clinic where she denied further syncopal episodes and was started on secretagogues for sicca symptoms.

Experiences of Two Centers in Percutaneous Ventricular Septal Defect Closure Using Konar Multifunctional Occluder

Background

Methods

Results

Conclusion

Early Resolution of New-Onset Left Bundle Branch Block After Transcatheter Aortic Valve Implantation With the SAPIEN 3 Valve

New-onset left bundle branch block (LBBB) is common after transcatheter aortic valve implantation (TAVI) but can resolve in the post-TAVI period. We sought to examine the incidence, predictors, and outcomes of early resolution of new-onset LBBB among TAVI recipients with a SAPIEN 3 (S3) valve. Among 1,203 S3-TAVI recipients without a pre-existing pacemaker or wide QRS complex at our institution between 2016 and 2019, we identified 143 patients who developed new-onset LBBB during TAVI and divided them according to the resolution or persistence of LBBB by the next day post-TAVI to compare high-degree atrioventricular block (HAVB) and permanent pacemaker (PPM) rates. Patients with resolved LBBB (n = 74, 52%), compared with those with persistent LBBB, were more often women and had a shorter QRS duration at baseline and post-TAVI, with a smaller S3 size and a shallower implantation depth. A multivariable logistic regression model demonstrated significant associations of post-TAVI QRS duration (per 10 ms increase, odds ratio = 0.60 [95% confidence interval = 0.44 to 0.82]) and implantation depth (per 1-mm-depth-increase, 0.77 [0.61 to 0.97]) with a lower likelihood of LBBB resolution. No patient with resolved LBBB developed HAVB within 30 days post-TAVI. Meanwhile, 8 patients (11.6%) with persistent LBBB developed HAVB. The 2-year PPM rate was significantly higher after persistent LBBB than after resolved LBBB (30.3% vs 4.5%, log-rank p <0.001), mainly driven by higher 30-day PPM rate (18.8% vs 0.0%). In conclusion, about half of new-onset LBBBs that occurred during S3-TAVI resolved by the next day post-TAVI without HAVB. In contrast, new-onset persistent LBBB may need follow-up with ambulatory monitoring within 30 days because of the HAVB risk.

Clinical management of conduction abnormalities following transcatheter aortic valve replacement: prospective evaluation of a standardized management pathway

Purpose

Limited evidence guides management of conduction abnormalities following TAVR. Standardized clinical pathways may reduce variability in care while minimizing bradyarrhythmic morbidity, length of stay (LOS), and pacemaker (PPM) implantation rates.

Methods

A multidisciplinary consensus pathway to standardize post-TAVR management was developed. We evaluated (1) pathway adherence; (2) LOS; (3) PPM implantation rates; (4) 1-month survival, and (5) late heart block. Exploratory analyses evaluated factors associated with PPM implantation.

Results

A total of 181 consecutive patients without prior PPM who underwent TAVR between February 2020 and February 2021 (mean age 77.9 ± 9.1, 38% women) were included. Average LOS was 3.0 days (± 2.7), and no deaths related to syncope/bradyarrhythmia were reported by 1 month. Overall, 93% of the 181 patients were managed by pathway; deviations were due to failure of discharge with a heart monitor when it was clinically indicated for either pre-existing RBBB or new PR prolongation/new LBBB. PPM implantation occurred in 19 patients by discharge, and 21 by 1-month (13%). In our exploratory analysis, pre-existing RBBB, transient peri-procedural heart block, and LOTUS valves were associated with pacemaker implantation: OR (CI) of 8.16 (3.06–21.78), 6.83 (1.94–24.03), and 8.32 (1.11–62.49), respectively.

Conclusions

This report illustrates that a standardized protocol for the management of conduction abnormalities after TAVR can be implemented with high compliance, safe management of conduction disturbance, and relatively short LOS with discharge supported by ambulatory monitoring.

Leadless Pacemaker Implantation in a Patient With Diminutive Subclavian Veins

Conventional pacemakers have a longstanding history of preventing morbidity and mortality in patients with bradyarrhythmia and conduction disorders. While decades of advancements have improved pacemaker technology and implantation technique, insertion of transvenous leads and formation of a pectoral pocket can lead to complications, including pocket hematoma, pneumothorax, or infection. Leadless pacemakers were introduced in 2012 to address these complications; however, early leadless systems only provided single-chamber ventricular pacing. In 2020, an accelerometer-based atrial sensing feature was developed to allow for atrioventricular (AV) synchrony with these devices. Early evidence suggests that patients with sinus rhythm and AV block can benefit from single-chamber leadless pacing systems with an AV synchrony algorithm. As availability of these devices continues to broaden, identification of appropriate recipients has become increasingly relevant.

[Leadless pacemakers: results of a survey from implanter centers in the Lombardy region]

BACKGROUND

Transvenous pacing is nowadays the cornerstone of interventional management of bradyarrhythmias. It is still associated, however, with significant complications, mostly related to indwelling transvenous leads or device pocket. In order to reduce these complications, leadless pacemakers have been recently introduced into clinical practice, but no guidelines are yet available to indicate who are those patients that might benefit the most and whether leadless pacing should be preferred in the old or young population. This survey aims to describe the use of leadless pacemaker devices in a real-world setting.

METHODS

Eleven arrhythmia centers in the Lombardy region (out of a total of 17 participating centers) responded to the proposed questionnaire regarding patient characteristics and indications to leadless pacing.

RESULTS

Out of a total of 411 patients undergoing leadless pacing during 4.2 ± 0.98 years, the median age was 77 years, with 0.18% of patients having less than 18 years, 29.9% 18-65 years, 34.3% 65-80 years and 35.6% >80 years. The most common indication was slow atrial fibrillation (49% of patients), followed by atrioventricular block and sinoatrial dysfunction. Two centers reported in-hospital complications.

CONCLUSIONS

Leadless pacemakers proved to be a safe pacing strategy actually destined mostly to elderly patients.

Implantation of cardiac electronic devices in active COVID-19 patients: Results from an international survey

BACKGROUND

Cardiac implantable electronic device (CIED) implantation rates as well as the clinical and procedural characteristics and outcomes in patients with known active coronavirus disease 2019 (COVID-19) are unknown.

OBJECTIVE

The purpose of this study was to gather information regarding CIED procedures during active COVID-19, performed with personal protective equipment, based on an international survey.

METHODS

Fifty-three centers from 13 countries across 4 continents provided information on 166 patients with known active COVID-19 who underwent a CIED procedure.

RESULTS

The CIED procedure rate in 133,655 hospitalized COVID-19 patients ranged from 0 to 16.2 per 1000 patients (P <.001). Most devices were implanted due to high-degree/complete atrioventricular block (112 [67.5%]) or sick sinus syndrome (31 [18.7%]). Of the 166 patients in the study survey, the 30-day complication rate was 13.9% and the 180-day mortality rate was 9.6%. One patient had a fatal outcome as a direct result of the procedure. Differences in patient and procedural characteristics and outcomes were found between Europe and North America. An older population (76.6 vs 66 years; P <.001) with a nonsignificant higher complication rate (16.5% vs 7.7%; P = .2) was observed in Europe vs North America, whereas higher rates of critically ill patients (33.3% vs 3.3%; P <.001) and mortality (26.9% vs 5%; P = .002) were observed in North America vs Europe.

CONCLUSION

CIED procedure rates during known active COVID-19 disease varied greatly, from 0 to 16.2 per 1000 hospitalized COVID-19 patients worldwide. Patients with active COVID-19 infection who underwent CIED implantation had high complication and mortality rates. Operators should take these risks into consideration before proceeding with CIED implantation in active COVID-19 patients.

Symptomatic second-degree atrioventricular block in a recreational athlete

This case study provides an example of bradycardia associated with an increase in exercise training in a recreational athlete. Although recognised among high-level endurance athletes, this case demonstrates the potential negative effects of exercise on the heart in a patient participating in the levels of exercise recommended by Public Health England. It adds weight to the ongoing discussion of the incomplete understanding of the level of exercise needed to induce pathological changes in cardiac physiology. We discuss the investigations that led us to our diagnosis, highlighting the importance of a detailed exercise history in patients who present with palpitations and provide a potential explanation of how this phenomenon may have occurred. Currently, bradycardia induced by exercise has been managed through pacemaker insertion or complete cessation of exercise. This report demonstrates effective treatment through a period of exercise cessation and slow reintroduction of exercise training.

Fully implantable and bioresorbable cardiac pacemakers without leads or batteries

Temporary cardiac pacemakers used in periods of need during surgical recovery involve percutaneous leads and externalized hardware that carry risks of infection, constrain patient mobility and may damage the heart during lead removal. Here we report a leadless, battery-free, fully implantable cardiac pacemaker for postoperative control of cardiac rate and rhythm that undergoes complete dissolution and clearance by natural biological processes after a defined operating timeframe. We show that these devices provide effective pacing of hearts of various sizes in mouse, rat, rabbit, canine and human cardiac models, with tailored geometries and operation timescales, powered by wireless energy transfer. This approach overcomes key disadvantages of traditional temporary pacing devices and may serve as the basis for the next generation of postoperative temporary pacing technology.

Leadless Pacemaker Implantation in a Patient With Previous Aortic, Mitral, and Tricuspid Valve Interventions

An 81-year-old patient with previous transcatheter aortic valve replacement, transcatheter mitral valve repair, and conventional biological tricuspid valve (TV) replacement presented with symptomatic complete atrioventricular block. Pacemaker implantation was performed under mild sedation, through a 27 Fr outer-diameter right femoral venous sheath. Fluoroscopy-guided TV crossing was performed using the Micra Transcatheter Pacing System (Medtronic) aiming for a right ventricular septal position.

Left bundle branch pacing shortened the QRS duration of a right bundle branch block

Left bundle branch pacing (LBBP) has recently emerged as a novel physiological pacing technique with a paced morphology of a pseudoright bundle branch block (RBBB). We herein present a 63-year-old man with a high-degree atrioventricular block and complete RBBB, whose intrinsic QRS duration and terminal R' wave duration in V1 were significantly shortened after LBBP and further shortened with the increase in output.