Two-year Outcomes of Micra AV Leadless Pacemakers in the Micra AV CED Study.

BACKGROUND AND AIMS: Leadless pacing is a safe and effective alternative to transvenous pacing for bradycardia. Micra AV is a leadless, single-device solution that provides AV-synchronous ventricular pacing therapy. Early results from the Micra AV CED study showed reductions in short-term complications associated with the Micra AV leadless pacemaker among US Medicare patients. The objective of this study is to compare chronic complications, reinterventions, and all-cause mortality at 2 years between patients implanted with a Micra AV leadless pacemaker and a traditional dual-chamber transvenous (DC TV) pacemaker. METHODS: Patients implanted with a Micra AV leadless pacemaker (N=7,552) or a DC TV pacemaker (N=110,558) in 2020 and 2021 were identified using device registration-linked Medicare administrative claims data. Competing risk models compared the unadjusted and propensity score overlap weight-adjusted complication, reintervention, and all-cause mortality rates of Micra AV and DC TV patients at two years. RESULTS: Micra AV patients had significantly more comorbidities (end-stage renal disease 14.9% vs. 2.0%, p-value <0.0001; renal dysfunction: 47.9% vs. 34.2%, p-value <0.0001; diabetes 46.2% vs. 38.3%, p-value <0.001; congestive heart failure 41.4% vs. 30.6%, p-value <0.0001). Two years post-implant, Micra AV patients had lower complication rates (adj. 5.3% vs. 9.6%, HR=0.54, 95% CI 0.49-0.61, p-value <0.0001) and lower reintervention rates (adj. 3.5% vs. 5.6%, HR=0.62, 95% CI 0.54-0.72, p-value <0.0001) than DC-TV patients. Upgrades to cardiac resynchronization therapy were low in both groups (adj. 1.6% vs. 1.7%, p-value=0.40), as were Micra AV upgrades to a dual-chamber system (adj. 1.4%). All-cause mortality rates remained higher in Micra AV than in DC-TV patients (unadj. HR=2.48, 95% CI 2.35-2.62, p-value <0.0001; adj. HR=1.53, 95% CI 1.44-1.62, p-value <0.0001). CONCLUSION: Patients implanted with Micra AV had lower complications and reintervention rates at two years than patients implanted with a traditional DC-TV pacemaker. All-cause mortality remained higher in Micra AV patients, likely due to their higher comorbidity burden and other differences in baseline characteristics. TRIAL REGISTRATION: ClinicalTrials.gov ID NCT04235491.

Costs, efficiency, and patient-reported outcomes associated with suture-mediated percutaneous closure for atrial fibrillation ablation: Secondary analysis of a randomized clinical trial.

INTRODUCTION: To evaluate the cost and efficiency of suture-mediated percutaneous closure (SMC) compared to manual compression (MC) after atrial fibrillation (AF) ablation. SMC has been demonstrated to be efficacious in reducing hemostasis and bedrest times after AF ablation. To date, randomized data comparing the direct and indirect cost between the two techniques have not been described. METHODS: We conducted a 1:1 randomized trial comparing SMC to MC following AF ablation. The primary endpoints have been previously published. However, secondary endpoints pertinent to indirect cost including complication rates, hospital utilization (i.e., delays in discharge, additional patient encounters, nursing utilization), pain, patient reported outcomes, as well as the direct costs of care associated with AF ablation were collected. We also performed secondary analysis of the primary endpoint to evaluate for a learning curve, and subgroups analysis comparing efficacy across different numbers of access sites and compared to those in the MC group with a figure-of-eight suture (Fo8), that could potentially have impacted the relative efficiency of the procedure. RESULTS: A total of 107 patients were randomized and included: 53 in the SMC group and 54 in MC. A learning curve was observed in the SMC group between the first and second half of the study group (p = 0.037), with no such difference in the MC group. After accounting for the number of access sites, time to hemostasis remained shorter in the SMC Group (p = 0.002). Compared to those in the Fo8 arm (n = 37), the time to hemostasis remained shorter in the SMC group (p = 0.001). Among those planned for same-day discharge, there were more delays in the MC group (31.5% vs. 11.3%, p = 0.0144). Rates of major and minor complications were similar between SMC and MC groups at discharge (p = 0.243) and 30 days (p = 1.00), as were nursing utilization, self-reported pain, and overall patient reported outcomes. The overall cost of care related to the procedure was similar between the MC and SMC groups ($56 533.65 [$45 699.47, $66 987.64] vs. $57 050.44 [$47 251.40, $66 426.34], p = 0.601). CONCLUSION: SMC has been shown to decrease time to hemostasis and ambulation and facilitate earlier same-day discharge after AF ablation without an increase in direct or indirect costs.

Spontaneous fluctuation in atrial fibrillation burden and duration in patients with implantable loop monitors.

BACKGROUND: Most studies of device-detected atrial fibrillation (AF) have recommended indefinite anticoagulation once a patient crosses a particular threshold for AF duration or burden. However, durations and burdens are known to fluctuate over time, but little is known about the magnitude of spontaneous fluctuations and the potential impact on anticoagulation decisions. OBJECTIVE: To quantify spontaneous fluctuations in AF duration and burden in patients with implantable loop recorders (ILRs) METHODS: We reviewed all ILR interrogations for patients with non-permanent AF at our institution from 2018 to 2023. We excluded patients treated with rhythm control. The duration of longest AF episode at each interrogation was classified as < 6, 6-24, and > 24 h, and the AF burden reported at each interrogation was classified as < 2%, 2%-11.4%, and > 11.4%. RESULTS: Out of 156 patients, the mean age at ILR implant was 70.9 ± 12.5 years, CHA2DS2-VASc score was 4.2 ± 1.8, duration of ILR follow-up was 23.4 ± 11.2 months, and number of ILR interrogations per patient was 18.0 ± 8.9. The duration of longest AF episode at any point during follow-up was < 6 , 6-24 , and > 24 h in 110, 30, and 16 patients, respectively. Among the 30 patients with a longest AF episode of 6-24 h at some point during follow-up, out of 594 total ILR interrogations, only 75 (12%) showed a longest episode of 6-24 h. In the remaining 519 interrogations, the longest episode was < 6 h. In patients with a longest episode of > 24 h at any point during follow-up (n = 16), only 47 out of 320 total ILR interrogations (15%) showed an episode of > 24 h. When evaluating AF burden, 96, 38, and 22 patients had maximum reported AF burdens of < 2%, 2%-11.4%, and > 11.4% at any point during ILR follow-up. Among those with a maximum burden of 2%-11.4% at some point during follow-up (n = 38), out of 707 ILR interrogations, only 76 (11%) showed a burden of 2%-11.4%. In the remaining 631 interrogations, the burden was < 2%. In the 22 patients with a burden > 11.4% at some point during follow-up, only 80 out of 480 interrogations (17%) showed a burden of > 11.4%. In 65% of interrogations, the burden was < 2%. CONCLUSION: Significant, spontaneous fluctuations in AF burden and duration are common in patients with ILRs. Even in patients with AF episodes of 6-24 h or > 24 h at some point during follow-up, the vast majority of interrogations show episodes of < 6 h. Similarly, in patients with burdens of 2%-11.4% or > 11.4% at some point during follow-up, the vast majority of interrogations show burdens of < 2%. More data are needed to determine whether crossing an AF burden or duration threshold once is sufficient to merit lifelong anticoagulation or whether spontaneous fluctuations in AF burden and duration should impact anticoagulation decisions.

Procedural and long-term outcomes of tunneled transvenous leads.

BACKGROUND: Lead-related venous stenosis and occlusion can complicate the insertion or replacement of transvenous leads in patients with cardiac implantable electronic devices (CIEDs). A possible solution is to tunnel the lead from the contralateral vasculature to the ipsilateral generator. Procedural complications and long-term outcomes remain unclear with this technique. OBJECTIVE: We sought to assess outcomes of tunneled transvenous leads. METHODS: We retrospectively identified all patients who underwent transvenous CIED lead tunneling to a contralateral pocket at our institution between 2014 and 2024. Clinical characteristics, indications for lead implantation, postoperative complications, and long-term outcomes were collected. RESULTS: We identified that 27 patients underwent transvenous lead tunneling at our institution. Most patients were men (20, 74%) with a mean age of 68.8 ± 18.3 years. Most patients had nonischemic cardiomyopathy (16, 59%) with a mean ejection fraction of 29.3% ± 11.3%. The tunneled leads were coronary sinus leads (20, 74%), followed by defibrillator leads (5, 18.5%) and right ventricular pacing leads (2, 7.4%). Implantation procedures were primarily for device upgrade (18), lead revisions (8), or de novo lead placement (1). No postoperative complications were seen. Patients were followed for a mean of 2.2 ± 1.4 years. One tunneled defibrillator lead (3.7%) had low shock impedance 3 years after implantation, which was monitored and did not require an intervention. CONCLUSION: In patients with ipsilateral venous occlusion, contralateral lead tunneling appears to be an effective and safe approach to manage patients with CIEDs and occluded ipsilateral subclavian veins.

Managing superior vena cava syndrome in patients with cardiac implantable electronic device leads: Strategies and considerations.

BACKGROUND: Data on transvenous (TV) lead-associated superior vena cava (SVC) syndrome are limited. The management of this problem might require a multidisciplinary approach, often involving transvenous lead extraction (TLE) followed by angioplasty and stenting. OBJECTIVE: The purpose of this study was to describe the management and outcome of TV lead-associated SVC syndrome. METHODS: We retrospectively identified patients with a diagnosis of SVC syndrome and TV leads at Emory Healthcare between 2015 and 2023. RESULTS: Fifteen patients with lead-related SVC syndrome were identified. The cohort average age was 50 years. Symptoms included swelling of the face, neck, and upper extremities (67%); shortness of breath (53%); and lightheadedness (40%). Patients had an average of 2 ± 0.7 leads crossing the SVC, with a lead dwell time of 9.8 ± 7.5 years. Thirteen patients were managed with TLE, followed by SVC stenting and angioplasty in 10 and angioplasty alone in 2; 1 patient had no intervention after TLE. One patient was managed with anticoagulation, and another had angioplasty and stenting with lead jailing. One patient experienced SVC perforation and cardiac tamponade during SVC stenting, which was managed successfully with a covered stent and pericardiocentesis. Among the 12 patients with TLE and angioplasty ± stenting, 7 underwent reimplantation of a transvenous lead. Two of those patients had symptoms recurrence, and none of the 5 patients without lead reimplantation had recurrence of symptoms. CONCLUSION: Lead-related SVC syndrome management requires a multidisciplinary approach often including TLE followed by angioplasty and stenting. Avoiding TV lead reimplantation might help reduce symptoms recurrence.

A leadless ventricular pacemaker providing atrioventricular synchronous pacing in the real-world setting: 12-Month results from the Micra AV post-approval registry.

BACKGROUND: Advances in leadless pacemaker technology have enabled accelerometer-based atrioventricular (AV) synchronous pacing by sensing atrial mechanical contraction. OBJECTIVE: The purpose of this study was to report the performance of the Micra AV leadless pacemaker from the worldwide Micra AV post-approval registry (PAR) through 12 months. METHODS: The Micra AV PAR is a prospective, single-arm, observational registry designed to assess the safety and effectiveness of Micra AV in a real-world setting. For the present interim analysis, major complications and system revisions through 12 months were summarized and compared to a historical cohort of 2667 patients implanted with a transvenous dual-chamber pacing system. RESULTS: The device was successfully implanted in 796 of 801 patients (99.4%) at 97 centers in 19 countries. Micra AV patients were older (74.1 years vs 71.1 years; P < .0001) with a higher incidence of renal disease (22.3% vs 9.8%; P < .0001) compared with transvenous dual-chamber patients. Through 12 months, the major complication rate was 3.7% in Micra AV patients compared with 8.8% in transvenous dual-chamber patients (hazard ratio 0.42; 95% confidence interval 0.28-0.61; P < .001). The system revision rate was 1.5% in Micra AV patients compared with 5.5% for transvenous dual-chamber patients (hazard ratio 0.25; 95% confidence interval 0.13-0.47; P < .001); this reduction was largely driven by the absence of lead dislodgments requiring revision. The median AV synchrony index was 79.4% (interquartile range 65.2%-86.4%) in patients paced >90%. CONCLUSION: The Micra AV leadless pacemaker was implanted with a high rate of success in patients with multiple comorbidities, with a significantly lower rate of complications and system revisions through 12 months compared to a historical cohort of patients with transvenous dual-chamber pacemakers.

Chronic kidney disease and transvenous cardiac implantable electronic device infection-is there an impact on healthcare utilization, costs, disease progression, and mortality?

AIMS: Cardiac implantable electronic device (CIED) infections are a burden to hospitals and costly for healthcare systems. Chronic kidney disease (CKD) increases the risk of CIED infections, but its differential impact on healthcare utilization, costs, and outcomes is not known. METHODS AND RESULTS: This retrospective analysis used de-identified Medicare Fee-for-Service claims to identify patients implanted with a CIED from July 2016 to December 2020. Outcomes were defined as hospital days and costs within 12 months post-implant, post-infection CKD progression, and mortality. Generalized linear models were used to calculate results by CKD and infection status while controlling for other comorbidities, with differences between cohorts representing the incremental effect associated with CKD. A total of 584 543 patients had a CIED implant, of which 26% had CKD and 1.4% had a device infection. The average total days in hospital for infected patients was 23.5 days with CKD vs. 14.5 days (P < 0.001) without. The average cost of infection was $121 756 with CKD vs. $55 366 without (P < 0.001), leading to an incremental cost associated with CKD of $66 390. Infected patients with CKD were more likely to have septicaemia or severe sepsis than those without CKD (11.0 vs. 4.6%, P < 0.001). After infection, CKD patients were more likely to experience CKD progression (hazard ratio 1.26, P < 0.001) and mortality (hazard ratio 1.89, P < 0.001). CONCLUSION: Cardiac implantable electronic device infection in patients with CKD was associated with more healthcare utilization, higher cost, greater disease progression, and greater mortality compared to patients without CKD.

Sex-based outcomes of subcutaneous implantable cardioverter-defibrillator and impact of surgical technique.

BACKGROUND: Because of differences in chest wall anatomy, female patients may have higher rates of subcutaneous implantable cardioverter-defibrillator (S-ICD) pocket-related complications. OBJECTIVE: We sought to evaluate sex-based outcomes after S-ICD implantation. METHODS: Patients implanted with an S-ICD at Emory Healthcare between 2010 and 2023 were included in the analysis. Patients' clinical characteristics and post-S-ICD implantation complications were collected. RESULTS: There were 429 male patients (68%) and 199 female patients (32%) observed for a median duration of 2.3 years (0.6-4.4 years). Male and female patients had comparable rates of diabetes (28%), end-stage renal disease (29.5%), ejection fraction (30.2% ± 13.4%), and body mass index (29.1 ± 6.6 kg/m2). There was no statistical difference in the incidence of shocks between men and women (26.3% vs 20.1%; P = .09), including appropriate shocks (14.7% vs 12%; P = .98) and inappropriate shocks (11.7% vs 9.5%; P = .98). Pocket-related complications occurred in 21 patients; these included pocket infection (n = 12), wound dehiscence (n = 7), and hematoma requiring drainage (n = 2). Female patients had a significantly higher pocket-related complication rate compared with male patients (7.2% vs 2.5%; P = .016). In controlling for age, body mass index, diabetes, and end-stage renal disease, female patients had higher odds of pocket-related complications compared with male patients (odds ratio, 3.15; 95% confidence interval, 1.27-7.75). Pocket-related complications decreased after 2018 compared with before 2018 (6% vs 2.6%, P = .052), mainly driven by reduction in complications in women (12.3% vs 3.2%; P = .034) but not in men (2.8% vs 2.4%; P = 1). CONCLUSION: In this cohort of S-ICD patients, women had a higher rate of post-S-ICD pocket-related complications that could be explained by sex-based differences in anatomy.

Accurate detection of lead malfunction from ECG-derived bipolar pacing stimulus amplitude.

BACKGROUND: One common mode of lead failure is insulation breach, which may result in myopotential noise and device malfunction. "Pseudo-unipolarization" of bipolar pacing stimuli, as observed from a routine 12-lead electrocardiogram (ECG) due to stimulus current leak, has been observed with insulation breaches. OBJECTIVE: We sought to characterize this electrocardiographic finding to detect this type of lead malfunction. METHODS: A total of 138 transvenous leads were analyzed, including 88 with known malfunction and 50 normal leads. The amplitude of a bipolar pacing stimulus on the ECG was recorded and compared with a control data set of newly implanted leads with bipolar stimuli normalized for output. RESULTS: The malfunction group consisted of 61% right atrium and 39% right ventricle leads with mean pacing output of 2.74 V at 0.5 ms. There was a significant difference in ECG bipolar stimulus amplitudes at time of identification of failure (7.89 ± 7.56 mm/V; P < .001) compared with those of normal leads (0.86 ± 0.41 mm/V). Receiver operating characteristic curve for the prediction of lead malfunction based on absolute ECG amplitude displayed an area under the curve of 0.93 (95% CI, 0.891-0.969). When normalized for programmed stimulus output, a cutoff of 5 mm/V demonstrated a sensitivity of 91% and a specificity of 92% (area under the curve, 0.967; 95% CI, 0.938-0.996). CONCLUSION: The maximum amplitude of a bipolar pacing stimulus on the ECG is significantly lower in normal functioning leads compared with those with known malfunction. This simply derived variable demonstrated good accuracy at identifying lead failure due to insulation breach.

Impact of omitting the intravenous heparin bolus on outcomes of leadless pacemaker implantation.

BACKGROUND: Early guidance recommended a bolus of intravenous heparin at the beginning of leadless pacemaker (LP) implantation procedures. However, due to concern about bleeding complications, more recent practice has tended toward omitting the bolus and only running a continuous heparin infusion through the introducer sheath. The impact of omitting the heparin bolus on procedural outcomes is not clear. METHODS: We reviewed all Medtronic Micra LP implants at our institution from 9/2014 to 9/2022. The decision to bolus with heparin was at operator discretion. RESULTS: Among 621 LP implants, 326 received an intravenous heparin bolus, 243 did not, and 52 patients were excluded because heparin bolus status could not be confirmed. There was a trend toward more frequent omission of the heparin bolus with more recent implants. Median follow-up after LP implant was 14.3 (interquartile range [IQR]: 8.4-27.9) months. There was no difference between heparin bolus and no bolus groups in the number of device deployments/recaptures (1.42 ± 0.81 vs. 1.31 ± 0.66, p = .15). Implant-related adverse events were also similar between heparin bolus and no bolus groups: access-site hematoma requiring intervention (7 vs. 5, p = .99), pseudoaneurysm (1 vs. 1, p = .99), cardiac perforation (1 vs. 1, p = .99), intraprocedural device thrombus formation (2 vs. 4, p = .41), 30-day rehospitalization (21 vs. 15, p = .98), and 30-day all-cause mortality (16 vs. 14, p = .70). There was one additional nonfatal cardiac perforation in a patient who was excluded due to unknown heparin bolus status. Regarding device electrical parameters between heparin bolus and no bolus groups, there were no significant differences at the time of implant: pacing capture threshold 0.5 ± 0.4 vs. 0.5 ± 0.3, p = .10; pacing impedance 739.9 ± 226.4 vs. 719.1 ± 215.4, p = .52; R wave sensing 11.7 ± 5.7 vs. 12.0 ± 5.4, p = .34). Long-term device performance was also similar between groups. CONCLUSION: Omission of the systemic heparin bolus at the time of LP implantation appears safe in appropriately selected patients. Heparin bolus may still be considered in long cases requiring multiple device deployments or in patients at high risk for thrombotic complications.

Electrocardiographic predictors of atrial mechanical sensing in leadless pacemakers.

BACKGROUND: Leadless pacemakers (LPs) capable of VDD pacing allow for atrioventricular synchrony through mechanical sensing of atrial contraction. However, mechanical sensing is less reliable and less predictable than electrical sensing. OBJECTIVE: The purpose of this study was to evaluate P-wave amplitude during sinus rhythm from preoperative 12-lead electrocardiograms (ECGs) as a predictor for atrial mechanical sensing in patients undergoing VDD LP implantation. METHODS: Consecutive patients undergoing VDD LP implantation were included in this 2-center prospective cohort study. ECG parameters were evaluated separately and in combination for association with the signal amplitude of atrial mechanical contraction (A4). RESULTS: Eighty patients (median age 82 years; female 55%; mean body mass index [BMI] 25.8 kg/m2) were included in the study and 61 patients in the A4 signal analysis (19 patients in VVI mode during follow-up). Absolute (aVL, aVF, V1, V2) and BMI-adjusted (I, II, aVL, aVF, aVR, V1, V2) P-wave amplitudes from baseline ECGs demonstrated a statistically significant positive correlation with A4 signal amplitude (all P <.05). A combined P-wave signal amplitude of at least 0.2 mV in V1 and aVL was predictive, with specificity of 83% (95% confidence interval 67%-100%) for A4 signal ≥1 m/s2. We found a significant correlation of A4 signal amplitude and overall atrioventricular synchrony (P = .013). CONCLUSION: P-wave amplitudes in ECG leads aVL and V1 can predict A4 signal amplitude in patients with VDD LP and therefore the probability of successful AV synchronous pacing.

Pacing and Defibrillation Consideration in the Era of Transcatheter Tricuspid Valve Replacement.

PURPOSE OF REVIEW: Tricuspid regurgitation is a commonly encountered valvular pathology in patients with trans-tricuspid pacing or implantable cardioverter-defibrillator leads. Transcatheter tricuspid valve interventions are increasingly performed in patients at high surgical risk. Implantation of these valves can lead to the "jailing" of a trans-tricuspid lead. This practice carries both short- and long-term risks of lead failure and subsequent infection without the ability to perform traditional transvenous lead extraction. Herein, this manuscript reviews available therapeutic options for lead management in patients undergoing transcatheter tricuspid valve interventions. RECENT FINDINGS: The decision to jail a lead may be appropriate in certain high-risk cases, though extraction may be a better option in most cases given the variety of options for re-implant, including leadless pacemakers, valve-sparing systems, epicardial leads, leads placed directly through prosthetic valves, and the completely subcutaneous implantable-defibrillator. A growing number of patients meet the requirement for CIED implantation in the United States. A significant proportion of these patients will have tricuspid valve dysfunction, either related to or independent of their transvenous lead. As with any percutaneous intervention that has shown efficacy, the role of TTVI is also likely to increase as this therapy advances beyond the investigational phase. As such, the role of the heart team in the management of these patients will be increasingly critical in the years to come, and in those patients that have pre-existing CIED leads, we advocate for the involvement of an electrophysiologist in the heart team.

Recurrence of new-onset post-operative AF after cardiac surgery: detected by implantable loop recorders: A systematic review and Meta-analysis.

BACKGROUND: Atrial fibrillation (AF) is one of the most common complications after cardiac surgery. New-onset post-operative AF may signal an elevated risk of AF and associated outcomes in long-term follow-up. We aimed to estimate the rate of AF recurrence as detected by an implantable loop recorder (ILR) in patients experiencing post-operative AF within 30 days after cardiac surgery. METHODS: We searched MEDLINE, Embase and Cochrane CENTRAL to April 2023 for studies of adults who did not have known AF, experienced new-onset AF within 30 days of cardiac surgery and received an ILR. We pooled individual participant data on timing of AF recurrence using a random-effects model with a frailty model applied to a Cox proportional hazard analysis. RESULTS: From 8671 citations, 8 single-centre prospective cohort studies met eligibility criteria. Data were available from 185 participants in 7 studies, with a median follow-up of 1.7 (IQR: 1.3-2.8) years. All included studies were at a low risk of bias. Pooled AF recurrence rates following 30 post-operative days were 17.8% (95% CI 11.9%-23.2%) at 3 months, 24.4% (17.7%-30.6%) at 6 months, 30.1% (22.8%-36.7%) at 12 months and 35.3% (27.6%-42.2%) at 18 months. CONCLUSIONS: In patients who experience new-onset post-operative AF after cardiac surgery, AF recurrence lasting at least 30 s occurs in approximately 1 in 3 in the first year after surgery. The optimal frequency and modality to use for monitoring for AF recurrence in this population remain uncertain.

Leadless pacemakers at 5-year follow-up: the Micra transcatheter pacing system post-approval registry.

BACKGROUND AND AIMS: Prior reports have demonstrated a favourable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. Updated performance of the Micra VR leadless pacemaker through five years from the worldwide post-approval registry (PAR) was assessed. METHODS: All Micra PAR patients undergoing implant attempts were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 transvenous pacemaker patients using Fine-Gray competing risk models. RESULTS: 1809 patients were enrolled between July 2015 and March 2018 and underwent implant attempts from 179 centres in 23 countries with a median follow-up period of 51.1 months (IQR: 21.6-64.2). The major complication rate at 60 months was 4.5% [95% confidence interval (CI): 3.6%-5.5%] and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: .47, 95% CI: .36-.61; P < .001). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%-6.1%). System revisions among Micra patients were mostly for device upgrades (41.2%) or elevated thresholds (30.6%). There were no Micra removals due to infection noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.2% vs. 6.6%, P < .001). CONCLUSIONS: Long-term outcomes with the Micra leadless pacemaker continue to demonstrate low rates of major complications and system revisions and an extremely low incidence of infection.

Outcomes of tricuspid regurgitation after lead extraction.

INTRODUCTION: Transvenous leads have been implicated in tricuspid valve (TV) dysfunction, but limited data are available regarding the effect of extracting leads across the TV on valve regurgitation. The aim of this study is to quantify tricuspid regurgitation (TR) before and after lead extraction and identify predictors of worsening TR. METHODS: We studied 321 patients who had echocardiographic data before and after lead extraction. TR was graded on a scale (0 = none/trivial, 1 = mild, 2 = moderate, 3 = severe). A change of >1 grade following extraction was considered significant. RESULTS: A total of 321 patients underwent extraction of a total of 338 leads across the TV (1.05 ± 0.31 leads across the TV per patient). There was no significant difference on average TR grade pre- and postextraction (1.18 ± 0.91 vs. 1.15 ± 0.87; p = 0.79). TR severity increased after extraction in 84 patients, but was classified as significantly worse (i.e., >1 grade change in severity) in only 8 patients (2.5%). Use of laser lead extraction was associated with a higher rate of worsening TR postextraction (44.0% vs. 31.6%, p = 0.04). CONCLUSION: In our single-center analysis, extraction of leads across the TV did not significantly affect the extent of TR in most patients. Laser lead extraction was associated with a higher rate of worsening TR after extraction.

Predictive value of the PRAETORIAN score for defibrillation test success in patients with subcutaneous ICD: A subanalysis of the PRAETORIAN-DFT trial.

BACKGROUND: The PRAETORIAN score estimates the risk of failure of subcutaneous implantable cardioverter-defibrillator (S-ICD) therapy by using generator and lead positioning on bidirectional chest radiographs. The PRospective randomized compArative trial of subcutanEous implanTable cardiOverter-defibrillatoR ImplANtation with and without DeFibrillation Testing (PRAETORIAN-DFT) investigates whether PRAETORIAN score calculation is noninferior to defibrillation testing (DFT) with regard to first shock efficacy in spontaneous events. OBJECTIVE: This prespecified subanalysis assessed the predictive value of the PRAETORIAN score for defibrillation success in induced ventricular arrhythmias. METHODS: This multicenter investigator-initiated trial randomized 965 patients between DFT and PRAETORIAN score calculation after de novo S-ICD implantation. Successful DFT was defined as conversion of induced ventricular arrhythmia in <5 seconds from shock delivery within 2 attempts. Bidirectional chest radiographs were obtained after implantation. The predictive value of the PRAETORIAN score for DFT success was calculated for patients in the DFT arm. RESULTS: In total, 482 patients were randomized to undergo DFT. Of these patients, 457 (95%) underwent DFT according to protocol, of whom 445 (97%) had successful DFT and 12 (3%) had failed DFT. A PRAETORIAN score of ≥90 had a positive predictive value of 25% for failed DFT, and a PRAETORIAN score of <90 had a negative predictive value of 99% for successful DFT. A PRAETORIAN score of ≥90 was the strongest independent predictor for failed DFT (odds ratio 33.77; confidence interval 6.13-279.95; P < .001). CONCLUSION: A PRAETORIAN score of <90 serves as a reliable indicator for DFT success in patients with S-ICD, and a PRAETORIAN score of ≥90 is a strong predictor for DFT failure.

Outcomes of patients implanted with an atrioventricular synchronous leadless ventricular pacemaker in the Medicare population.

BACKGROUND: The Micra AV Coverage with Evidence Development study is a novel analysis of utilization and outcomes associated with Micra AV leadless pacing in US Medicare patients. OBJECTIVE: The purpose of this study was to describe patient characteristics, complications, and outcomes of patients implanted with a Micra AV leadless pacemaker compared with a contemporaneous cohort of patients implanted with a dual chamber transvenous pacemaker. METHODS: Patients implanted with Micra AV (n = 7471) or a dual chamber transvenous pacemaker (n = 107,800) from February 5, 2020, through December 1, 2021, were identified using device registry-linked Medicare claims data. Acute complications were assessed at 30 days, and chronic complications, reinterventions, and all-cause mortality were assessed at 6 months. RESULTS: Patients implanted with Micra AV had higher rates of end-stage renal disease (14.9% vs 2.0%; P < .0001) and overall comorbidity burden (mean Charlson Comorbidity Index 4.9 vs 3.8; P < .0001). There was no difference in the unadjusted rate of complications at 30 days (9.1% vs 8.7%; P = .61), and patients implanted with Micra AV had a significantly lower adjusted rate of complications (8.6% vs 11.0%; P < .0001). At 6 months, patients implanted with Micra AV had significantly lower rates of complications (adjusted hazard ratio 0.50; 95% confidence interval 0.43-0.57; P < .0001) and reinterventions (adjusted hazard ratio 0.46; 95% confidence interval 0.36-0.58; P < .0001). Patients implanted with Micra AV had higher all-cause mortality at 30 days and 6 months, likely because of differences in the underlying risk of mortality. CONCLUSION: Patients implanted with Micra AV had similar rates of complications at 30 days and significantly lower rates of complications and reinterventions at 6 months, despite being sicker than patients implanted with a transvenous pacemaker.

Update on Cardiovascular Implantable Electronic Device Infections and Their Prevention, Diagnosis, and Management: A Scientific Statement From the American Heart Association: Endorsed by the International Society for Cardiovascular Infectious Diseases.

The American Heart Association sponsored the first iteration of a scientific statement that addressed all aspects of cardiovascular implantable electronic device infection in 2010. Major advances in the prevention, diagnosis, and management of these infections have occurred since then, necessitating a scientific statement update. An 11-member writing group was identified and included recognized experts in cardiology and infectious diseases, with a career focus on cardiovascular infections. The group initially met in October 2022 to develop a scientific statement that was drafted with front-line clinicians in mind and focused on providing updated clinical information to enhance outcomes of patients with cardiovascular implantable electronic device infection. The current scientific statement highlights recent advances in prevention, diagnosis, and management, and how they may be incorporated in the complex care of patients with cardiovascular implantable electronic device infection.