A Modular Communicative Leadless Pacing-Defibrillator System.

BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (ICD) is associated with fewer lead-related complications than a transvenous ICD; however, the subcutaneous ICD cannot provide bradycardia and antitachycardia pacing. Whether a modular pacing-defibrillator system comprising a leadless pacemaker in wireless communication with a subcutaneous ICD to provide antitachycardia and bradycardia pacing is safe remains unknown. METHODS: We conducted a multinational, single-group study that enrolled patients at risk for sudden death from ventricular arrhythmias and followed them for 6 months after implantation of a modular pacemaker-defibrillator system. The safety end point was freedom from leadless pacemaker-related major complications, evaluated against a performance goal of 86%. The two primary performance end points were successful communication between the pacemaker and the ICD (performance goal, 88%) and a pacing threshold of up to 2.0 V at a 0.4-msec pulse width (performance goal, 80%). RESULTS: We enrolled 293 patients, 162 of whom were in the 6-month end-point cohort and 151 of whom completed the 6-month follow-up period. The mean age of the patients was 60 years, 16.7% were women, and the mean (±SD) left ventricular ejection fraction was 33.1±12.6%. The percentage of patients who were free from leadless pacemaker-related major complications was 97.5%, which exceeded the prespecified performance goal. Wireless-device communication was successful in 98.8% of communication tests, which exceeded the prespecified goal. Of 151 patients, 147 (97.4%) had pacing thresholds of 2.0 V or less, which exceeded the prespecified goal. The percentage of episodes of arrhythmia that were successfully terminated by antitachycardia pacing was 61.3%, and there were no episodes for which antitachycardia pacing was not delivered owing to communication failure. Of 162 patients, 8 died (4.9%); none of the deaths were deemed to be related to arrhythmias or the implantation procedure. CONCLUSIONS: The leadless pacemaker in wireless communication with a subcutaneous ICD exceeded performance goals for freedom from major complications related to the leadless pacemaker, for communication between the leadless pacemaker and subcutaneous ICD, and for the percentage of patients with a pacing threshold up to 2.0 V at a 0.4-msec pulse width at 6 months. (Funded by Boston Scientific; MODULAR ATP ClinicalTrials.gov NCT04798768.).

Managing Implanted Cardiac Electronic Devices in Patients With Severe Tricuspid Regurgitation: JACC State-of-the-Art Review.

Orthotopic transcatheter tricuspid valve replacement (TTVR) devices have been shown to be highly effective in reducing tricuspid regurgitation (TR), and interest in this therapy is growing with the recent commercial approval of the first orthotopic TTVR. Recent TTVR studies report preexisting cardiac implantable electronic device (CIED) transvalvular leads in ∼35% of patients, with entrapment during valve implantation. Concerns have been raised regarding the safety of entrapping leads and counterbalanced against the risks of transvenous lead extraction (TLE) when indicated. This Heart Valve Collaboratory consensus document attempts to define the patient population with CIED lead-associated or lead-induced TR, describe the risks of lead entrapment during TTVR, delineate the risks and benefits of TLE in this setting, and develop a management algorithm for patients considered for TTVR. An electrophysiologist experienced in CIED management should be part of the multidisciplinary heart team and involved in shared decision making.

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.

The utility and impact of outpatient telemetry monitoring in post-transcatheter aortic valve replacement patients.

BACKGROUND: Conduction disturbances are a common complication of transcatheter aortic valve replacement (TAVR). Mobile Cardiac Telemetry (MCT) allows for continuous monitoring with near "real time" alerts and has allowed for timely detection of conduction abnormalities and pacemaker placement in small trials. A standardized, systematic approach utilizing MCT devices post TAVR has not been widely implemented, leading to variation in use across hospital systems. OBJECTIVES: Our aim was to evaluate the utility of a standardized, systematic approach utilizing routine MCT to facilitate safe and earlier discharge by identifying conduction disturbances requiring permanent pacemaker (PPM) placement. We also sought to assess the occurrence of actionable arrhythmias in post-TAVR patients. METHODS: Using guidance from the JACC Scientific Expert Panel, a protocol was implemented starting in December 2019 to guide PPM placement post-TAVR across our health system. All patients who underwent TAVR from December 2019 to June 2021 across four hospitals within Northwell Health, who did not receive or have a pre-existing PPM received an MCT device at discharge and were monitored for 30 days. Clinical and follow-up data were collected and compared to pre initiative patients. RESULTS: During the initiative 693 patients were monitored with MCT upon discharge, 21 of whom required PPM placement. Eight of these patients had no conduction abnormality on initial or discharge ECG. 59 (8.6 %) patients were found to have new atrial fibrillation or flutter via MCT monitoring. There were no adverse events in the initiative group. Prior to the initiative, 1281 patients underwent TAVR over a one-year period. The initiative group had significantly shorter length of stay than pre-initiative patients (2.5 ± 4.5 vs 3.0 ± 3.8 days, p < 0.001) and lower overall PPM placement rate within 30 days post-TAVR (16 % vs 20.5 %, P = 0.0125). CONCLUSIONS: In our study, implementation of a standardized, systematic approach utilizing MCT in post-TAVR patients was safe and allowed for timely detection of conduction abnormalities requiring pacemaker placement. This strategy also detected new atrial fibrillation and flutter. Reduction in post TAVR pacemaker rate and length of stay were also noted although this effect is multifactorial.

Site-specific effects of dobutamine on cardiac conduction and refractoriness.

BACKGROUND: Isoproterenol, a non-specific beta agonist, is commonly used during electrophysiology studies (EPS). However, with the significant increase in the price of isoproterenol in 2015 and the increasing number of catheter ablations performed, the cost implications cannot be ignored. Dobutamine is a less expensive synthetic compound developed from isoproterenol with a similar mechanism to enhance cardiac conduction and shorten refractoriness, thus making it a feasible substitute with a lower cost. However, the use of dobutamine for EPS has not been well-reported in the literature. OBJECTIVE: To determine the site-specific effects of various doses of dobutamine on cardiac conduction and refractoriness and assess its safety during EPS. METHODS: From February 2020 to October 2020, 40 non-consecutive patients scheduled for elective EPS, supraventricular tachycardia, atrial fibrillation, and premature ventricular contraction ablations at a single center were consented and prospectively enrolled to assess the effect of dobutamine on the cardiac conduction system. At the end of each ablation procedure, measures of cardiac conduction and refractoriness were recorded at baseline and with incremental doses of dobutamine at 5, 10, 15, and 20 mcg/kg/min. For the primary analysis, the change per dose of dobutamine from baseline to each dosing level of dobutamine received by the patients, comparing atrioventricular node block cycle length (AVNBCL), ventricular atrial block cycle length (VABCL) and sinus cycle length (SCL), was tested using mixed-effect regression. For the secondary analysis, dobutamine dose level was tested for association with relative changes from baseline of each electrophysiologic parameter (SCL, AVNBCL, VABCL, atrioventricular node effective refractory period (AVNERP), AH, QRS, QT, QTc, atrial effective refractory period (AERP), ventricular effective refractory period (VERP), using mixed-effect regression. Changes in systolic and diastolic blood pressures were also assessed. The Holm-Bonferroni method was used to adjust for multiple testing. RESULTS: For the primary analysis there was no statistically significant change of AVNBCL and VABCL relative to SCL from baseline to each dose level of dobutamine. The SCL, AVNBCL, VABCL, AVNERP, AERP, VERP and the AH, and QT intervals all demonstrated a statistically significant decrease from baseline to at least one dose level with incremental dobutamine dosing. Two patients (5%) developed hypotension during the study and one patient (2.5%) received a vasopressor. Two patients (5%) had induced arrhythmias but otherwise no major adverse events were noted. CONCLUSION: In this study, there was no statistically significant change of AVNBCL and VABCL relative to SCL from baseline to any dose level of dobutamine. As expected, the AH and QT intervals, and the VABCL, VERP, AERP and AVNERP all significantly decreased from baseline to at least one dose level with an escalation in dobutamine dose. Dobutamine was well-tolerated and safe to use during EPS.

Lead Extraction and Mortality Among Patients With Cardiac Implanted Electronic Device Infection.

Importance: Complete hardware removal is a class I recommendation for cardiovascular implantable electronic device (CIED) infection, but practice patterns and outcomes remain unknown. Objective: To quantify the number of Medicare patients with CIED infections who underwent implantation from 2006 to 2019 and lead extraction from 2007 to 2019 to analyze the outcomes in these patients in a nationwide clinical practice cohort. Design, Setting, and Participants: This cohort study included fee-for-service Medicare Part D beneficiaries from January 1, 2006, to December 31, 2019, who had a de novo CIED implantation and a CIED infection more than 1 year after implantation. Data were analyzed from January 1, 2005, to December 31, 2019. Exposure: A CIED infection, defined as (1) endocarditis or infection of a device implant and (2) documented antibiotic therapy. Main Outcomes and Measures: The primary outcomes of interest were device infection, device extraction, and all-cause mortality. Time-varying multivariable Cox proportional hazards regression models were used to evaluate the association between extraction and survival. Results: Among 1 065 549 patients (median age, 78.0 years [IQR, 72.0-84.0 years]; 50.9% male), mean (SD) follow-up was 4.6 (2.9) years after implantation. There were 11 304 patients (1.1%) with CIED infection (median age, 75.0 years [IQR, 67.0-82.0 years]); 60.1% were male, and 7724 (68.3%) had diabetes. A total of 2102 patients with CIED infection (18.6%) underwent extraction within 30 days of diagnosis. Infection occurred a mean (SD) of 3.7 (2.4) years after implantation, and 1-year survival was 68.3%. There was evidence of highly selective treatment, as most patients did not have extraction within 30 days of diagnosed infection (9202 [81.4%]), while 1511 (13.4%) had extraction within 6 days of diagnosis and 591 (5.2%) had extraction between days 7 and 30. Any extraction was associated with lower mortality compared with no extraction (adjusted hazard ratio [AHR], 0.82; 95% CI, 0.74-0.90; P < .001). Extraction within 6 days was associated with even lower risk of mortality (AHR, 0.69; 95% CI, 0.61-0.78; P < .001). Conclusions and Relevance: In this study, a minority of patients with CIED infection underwent extraction. Extraction was associated with a lower risk of death compared with no extraction. The findings suggest a need to improve adherence to guideline-directed care among patients with CIED infection.

Safety and success of transvenous lead extraction using excimer laser sheaths: a meta-analysis of over 1700 patients.

AIMS: While numerous studies have demonstrated favourable safety and efficacy of the excimer laser sheath for transvenous lead extraction (TLE) in smaller cohorts, comprehensive large-scale investigations with contemporary data remain scarce. This study aims to evaluate the safety and performance of laser-assisted TLE through a meta-analysis of contemporary data. METHODS AND RESULTS: A systematic literature search was conducted to identify articles that assessed the safety and performance of the spectranetics laser sheath (SLS) II and GlideLight Excimer laser sheaths in TLE procedures between 1 April 2016 and 31 March 2021. Safety outcomes included procedure-related death and major/minor complications. Performance outcomes included procedural and clinical success rates. A random-effects, inverse-variance-weighting meta-analysis was performed to obtain the weighted average of the evaluated outcomes. In total, 17 articles were identified and evaluated, including 1729 patients with 2887 leads. Each patient, on average, had 2.3 ± 0.3 leads with a dwell time of 7.9 ± 3.0 years. The TLE procedural successes rate was 96.8% [1440/1505; 95% CI: (94.9-98.2%)] per patient and 96.3% [1447/1501; 95% CI: (94.8-97.4%)] per lead, and the clinical success rate per patient was 98.3% [989/1010, 95% CI: (97.4-99.0%)]. The procedure-related death rate was 0.08% [7/1729, 95% CI: (0.00%, 0.34%)], with major and minor complication rates of 1.9% [41/1729; 95% CI: (1.2-2.8%)] and 1.9% [58/1729; 95% CI: (0.8-3.6%)], respectively. CONCLUSION: This meta-analysis demonstrated that excimer laser sheath-assisted TLE has high success and low procedural mortality rates. It provides clinicians with a reliable and valuable resource for extracting indwelling cardiac leads which require advanced extraction techniques.

Lead management in patients undergoing percutaneous tricuspid valve replacement or repair: a 'heart team' approach.

Clinically significant tricuspid regurgitation (TR) has historically been managed with either medical therapy or surgical interventions. More recently, percutaneous trans-catheter tricuspid valve (TV) replacement and tricuspid trans-catheter edge-to-edge repair have emerged as alternative treatment modalities. Patients with cardiac implantable electronic devices (CIEDs) have an increased incidence of TR. Severe TR in this population can occur for multiple reasons but most often results from the interactions between the CIED lead and the TV apparatus. Management decisions in patients with CIED leads and clinically significant TR, who are undergoing evaluation for a percutaneous TV intervention, need careful consideration as a trans-venous lead extraction (TLE) may both worsen and improve TR severity. Furthermore, given the potential risks of 'jailing' a CIED lead at the time of a percutaneous TV intervention (lead fracture and risk of subsequent infections), consideration should be given to performing a TLE prior to a percutaneous TV intervention. The purpose of this 'state-of-the-art' review is to provide an overview of the causes of TR in patients with CIEDs, discuss the available therapeutic options for patients with TR and CIED leads, and advocate for including a lead management specialist as a member of the 'heart team' when making treatment decisions in patients TR and CIED leads.

Concomitant leadless pacing in pacemaker-dependent patients undergoing transvenous lead extraction for active infection: Mid-term follow-up.

BACKGROUND: The rate of transvenous lead extraction (TLE) due to cardiac implantable electronic device (CIED) infection continues to rise. CIED infections are associated with significant morbidity and mortality. Temporary pacing in patients with active CIED infections after TLE can be challenging. Leadless pacing has emerged as an alternative approach in this patient population. OBJECTIVE: The purpose of this study was to describe the outcomes of a strategy using concomitant leadless pacemaker implantation and TLE in patients with active infections and ongoing pacing requirements. METHODS: This study involved all leadless pacemaker implantation procedures performed during TLE between June 2018 and September 2022 in the setting of active infection. Demographic characteristics, procedural details, and clinical outcomes were analyzed. RESULTS: The study included 86 patients with indications for ongoing pacing, 60 (70%) men with mean age 77.4 ± 10.5 years, who underwent TLE and concomitant leadless pacemaker implantation in the setting of active infection. There were no procedure-related complications. Sixty-five patients (76%) had evidence of bacteremia, 80% of whom were discharged to complete their antimicrobial treatment. During a median follow-up of 163 days (interquartile range 57-403 days), there were no recurrent infections. Of the 25 deaths (29%) during the study period, 22 (88%) were unrelated to the initial infection. Nine deceased patients (36%) had methicillin-resistant Staphylococcus aureus or Candida infections, 3 of whom had persistent infection despite TLE. CONCLUSION: Leadless pacing is a safe and efficacious approach for the management of patients with pacing requirements that undergo CIED extraction in the setting of active infection.

Correlation between AV synchrony and device collected AM-VP sequence counter in atrioventricular synchronous leadless pacemakers: A real-world assessment.

INTRODUCTION: Micra atrioventricular (AV) provides leadless atrioventricular synchronous pacing by sensing atrial contraction (A4 signal). Real-world operation and reliability of AV synchrony (AVS) assessment using device data have not been described. The purposes of this study were to (1) assess the correlation between AVS and atrial mechanical sensed-ventricular pacing (AM-VP) percentages in patients with permanent high-degree AV block and (2) report on the real-world effectiveness of Micra AV. METHODS: The correlation between ECG-determined AVS in-clinic and device-collected %AM-VP was assessed using data from 40 patients with high-degree AV block enrolled in the Micra Atrial tRacking using a Ventricular AccELerometer (MARVEL) 2 study. A retrospective analysis to assess continuously-sampled %AM-VP since last session, device programming, and electrical parameters was performed using Micra AV transmissions from the Medtronic CareLink database. Patients with transmissions ≥180 days postimplant were included. RESULTS: Among the 40 MARVEL 2 AV block patients with a median %VP of 99.7%, AVS was highly correlated with AM-VP (median AVS 87.1%, median AM-VP 79.1%; R2 = 0.764, p < .001). The CareLink cohort included 4384 patients programmed to VDD mode. The mean A4 amplitude was 2.3 ± 1.8 m/s2 at implant and 2.3 ± 1.6 m/s2 at 28 weeks. In patients with %VP >90% (n = 1662), the median %AM-VP was 74.7%. For the full cohort, median %VP was 65.6% and median projected battery longevity was 10.5 years. CONCLUSION: In patients with a high pacing burden, %AM-VP provides a reasonable estimation of AVS. The first large real-world analysis of Micra AV patients with >90% VP showed stable atrial sensing over time with a median %AM-VP, a correlate of AVS, of 74.7%.

Same-day discharge after transvenous lead extraction: feasibility and outcomes.

AIMS: Same-day discharge (SDD) is safe for patients undergoing electrophysiology procedures. There is no existing data regarding SDD for patients undergoing transvenous lead extraction (TLE). We report our experience with SDD for patients undergoing TLE. METHODS AND RESULTS: The study group included patients undergoing TLE between February 2020 and July 2021 without an infectious indication. A modified SDD protocol for device implants/ablations was applied to TLE patients. Patient characteristics, extraction details, outcomes, and complications were reviewed. Of 239 patients undergoing TLE, 210 were excluded (94 infections and 116 did not meet SDD criteria). Of the remaining 29 patients, seven stayed due to patient preference and 22 were discharged home the same day. The SDD group had an average age of 65.9 ± 12 (47-84), 41% female, and LVEF of 52.2 ± 18% (10-80). The indication for TLE was malfunction (20), upgrade (4), advisory lead (2), and magnetic resonance imaging compatibility (1). Extractions included four implantable cardioverter-defibrillators (ICDs), 17 pacemakers (PPM), and one cardiac resynchronization therapy (CRT)-P system. The leads were 9.6 years (1.5-21.7) old, and 1.8 leads were removed per patient (1-3); the lead extraction difficulty (LED) score was 11.6 ± 7. Twenty underwent cardiovascular implantable electronic device (CIED) re-implantation (2 ICD, 3 CRT-D, 13 PPM, and 2 CRT-P). For CIED re-implants, patients sent a remote transmission the next day, and all patients received a next-day call. There were no procedure or device-related issues, morbidities, or mortalities in the 30 days after discharge. CONCLUSION: Same-day discharge after TLE for non-infectious aetiologies is safe and feasible in a select group of patients with early procedure completion who meet strict SDD criteria.

Prospective Evaluation of the Correlation Between Gated Cardiac Computed Tomography Detected Vascular Fibrosis and Ease of Transvenous Lead Extraction.

BACKGROUND: Difficulty of lead extraction does not track well with procedural complications, but several small retrospective studies have lead fibrosis on computed tomography as an important indicator of difficult lead extraction. The purpose of the present study was to apply a standardized gated cardiac computed tomography (CT) protocol to assess fibrosis and study it prospectively to examine the need for powered sheaths and risk outcomes. METHODS: We performed a prospective, blinded, multicenter, international study at high-volume lead extraction centers and included patients referred for transvenous lead extraction with at least one lead with a dwell time >1 year and ability to receive a cardiac CT. The degree of fibrosis (as measured by amount of lead adherence to vessel wall) was graded on a scale of 1 to 4 by dedicated CT readers in 3 zones (vein entry to superior vena cava, superior vena cava, and right atrium to lead tip). The primary outcome of the study was number of extractions requiring powered sheaths at zone 2 for each fibrosis group. RESULTS: A total of 200 patients were enrolled in the trial with 196 completing full gated CT and lead extraction analysis. The primary endpoint of powered sheath (laser and mechanical) sheath use was significantly higher in patients with higher fibrosis seen on CT (scores 3+4; 67.8%) at the zone 2 compared to patients with lower fibrosis (scores 1+2; 38.6%; P<0.001). There were 5 major complications with 3 vascular lacerations all occurring in zone 2 in the study. CONCLUSIONS: Gated, contrasted CT can predict the need for powered sheaths by identification of fibrosis but did not identify an absolute low-risk cohort who would not need powered sheaths. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03772704.

Efficacy and Safety of an Extravascular Implantable Cardioverter-Defibrillator.

BACKGROUND: The extravascular implantable cardioverter-defibrillator (ICD) has a single lead implanted substernally to enable pause-prevention pacing, antitachycardia pacing, and defibrillation energy similar to that of transvenous ICDs. The safety and efficacy of extravascular ICDs are not yet known. METHODS: We conducted a prospective, single-group, nonrandomized, premarket global clinical study involving patients with a class I or IIa indication for an ICD, all of whom received an extravascular ICD system. The primary efficacy end point was successful defibrillation at implantation. The efficacy objective would be met if the lower boundary of the one-sided 97.5% confidence interval for the percentage of patients with successful defibrillation was greater than 88%. The primary safety end point was freedom from major system- or procedure-related complications at 6 months. The safety objective would be met if the lower boundary of the one-sided 97.5% confidence interval for the percentage of patients free from such complications was greater than 79%. RESULTS: A total of 356 patients were enrolled, 316 of whom had an implantation attempt. Among the 302 patients in whom ventricular arrhythmia could be induced and who completed the defibrillation testing protocol, the percentage of patients with successful defibrillation was 98.7% (lower boundary of the one-sided 97.5% confidence interval [CI], 96.6%; P<0.001 for the comparison with the performance goal of 88%); 299 of 316 patients (94.6%) were discharged with a working ICD system. The Kaplan-Meier estimate of the percentage of patients free from major system- or procedure-related complications at 6 months was 92.6% (lower boundary of the one-sided 97.5% CI, 89.0%; P<0.001 for the comparison with the performance goal of 79%). No major intraprocedural complications were reported. At 6 months, 25 major complications were observed, in 23 of 316 patients (7.3%). The success rate of antitachycardia pacing, as assessed with generalized estimating equations, was 50.8% (95% CI, 23.3 to 77.8). A total of 29 patients received 118 inappropriate shocks for 81 arrhythmic episodes. Eight systems were explanted without extravascular ICD replacement over the 10.6-month mean follow-up period. CONCLUSIONS: In this prospective global study, we found that extravascular ICDs were implanted safely and were able to detect and terminate induced ventricular arrhythmias at the time of implantation. (Funded by Medtronic; ClinicalTrials.gov number, NCT04060680.).

Pacemaker lead-related endocarditis with Neisseria sicca.

We report the first known case of Neisseria sicca-associated pacemaker lead endocarditis-a disease whose incidence and mortality are growing. A woman in her 70s with a history of transcatheter aortic valve replacement and pacemaker placement 7 months earlier presented with recurrent fevers. She visited the emergency department several times during the past 2 months for these fevers, and she had been given oral antibiotics for presumed urinary tract infections. Investigations revealed blood cultures growing N. sicca Although transthoracic echocardiogram was negative, transesophageal echocardiogram showed two vegetations on the right atrial lead which suggested pacemaker lead-associated endocarditis. A complete pacemaker and lead extraction was performed, and the patient recovered completely and was discharged home to complete 6 weeks of intravenous ceftriaxone with plans for follow-up echocardiography. We hope that this case will contribute to the growing body of literature regarding device infections, thus leading to earlier identification and treatment.