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.

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.

Adaptive versus conventional cardiac resynchronisation therapy in patients with heart failure (AdaptResponse): a global, prospective, randomised controlled trial.

BACKGROUND: Continuous automatic optimisation of cardiac resynchronisation therapy (CRT), stimulating only the left ventricle to fuse with intrinsic right bundle conduction (synchronised left ventricular stimulation), might offer better outcomes than conventional CRT in patients with heart failure, left bundle branch block, and normal atrioventricular conduction. This study aimed to compare clinical outcomes of adaptive CRT versus conventional CRT in patients with heart failure with intact atrioventricular conduction and left bundle branch block. METHODS: This global, prospective, randomised controlled trial was done in 227 hospitals in 27 countries across Asia, Australia, Europe, and North America. Eligible patients were aged 18 years or older with class 2-4 heart failure, an ejection fraction of 35% or less, left bundle branch block with QRS duration of 140 ms or more (male patients) or 130 ms or more (female patients), and a baseline PR interval 200 ms or less. Patients were randomly assigned (1:1) via block permutation to adaptive CRT (an algorithm providing synchronised left ventricular stimulation) or conventional biventricular CRT using a device programmer. All patients received device programming but were masked until procedures were completed. Site staff were not masked to group assignment. The primary outcome was a composite of all-cause death or intervention for heart failure decompensation and was assessed in the intention-to-treat population. Safety events were collected and reported in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02205359, and is closed to accrual. FINDINGS: Between Aug 5, 2014, and Jan 31, 2019, of 3797 patients enrolled, 3617 (95·3%) were randomly assigned (1810 to adaptive CRT and 1807 to conventional CRT). The futility boundary was crossed at the third interim analysis on June 23, 2022, when the decision was made to stop the trial early. 1568 (43·4%) of 3617 patients were female and 2049 (56·6%) were male. Median follow-up was 59·0 months (IQR 45-72). A primary outcome event occurred in 430 of 1810 patients (Kaplan-Meier occurrence rate 23·5% [95% CI 21·3-25·5] at 60 months) in the adaptive CRT group and in 470 of 1807 patients (25·7% [23·5-27·8] at 60 months) in the conventional CRT group (hazard ratio 0·89, 95% CI 0·78-1·01; p=0·077). System-related adverse events were reported in 452 (25·0%) of 1810 patients in the adaptive CRT group and 440 (24·3%) of 1807 patients in the conventional CRT group. INTERPRETATION: Compared with conventional CRT, adaptive CRT did not significantly reduce the incidence of all-cause death or intervention for heart failure decompensation in the included population of patients with heart failure, left bundle branch block, and intact AV conduction. Death and heart failure decompensation rates were low with both CRT therapies, suggesting a greater response to CRT occurred in this population than in patients in previous trials. FUNDING: Medtronic.

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.

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.

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.

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.

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.

Efficacy and Safety of Appropriate Shocks and Antitachycardia Pacing in Transvenous and Subcutaneous Implantable Defibrillators: Analysis of All Appropriate Therapy in the PRAETORIAN Trial.

BACKGROUND: The PRAETORIAN trial (A Prospective, Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter Defibrillator Therapy) showed noninferiority of subcutaneous implantable cardioverter defibrillator (S-ICD) compared with transvenous implantable cardioverter defibrillator (TV-ICD) with regard to inappropriate shocks and complications. In contrast to TV-ICD, S-ICD cannot provide antitachycardia pacing for monomorphic ventricular tachycardia. This prespecified secondary analysis evaluates appropriate therapy and whether antitachycardia pacing reduces the number of appropriate shocks. METHODS: The PRAETORIAN trial was an international, investigator-initiated randomized trial that included patients with an indication for implantable cardioverter defibrillator (ICD) therapy. Patients with previous ventricular tachycardia <170 bpm or refractory recurrent monomorphic ventricular tachycardia were excluded. In 39 centers, 849 patients were randomized to receive an S-ICD (n=426) or TV-ICD (n=423) and were followed for a median of 49.1 months. ICD programming was mandated by protocol. Appropriate ICD therapy was defined as therapy for ventricular arrhythmias. Arrhythmias were classified as discrete episodes and storm episodes (≥3 episodes within 24 hours). Analyses were performed in the modified intention-to-treat population. RESULTS: In the S-ICD group, 86 of 426 patients received appropriate therapy, versus 78 of 423 patients in the TV-ICD group, during a median follow-up of 52 months (48-month Kaplan-Meier estimates 19.4% and 17.5%; P=0.45). In the S-ICD group, 83 patients received at least 1 shock, versus 57 patients in the TV-ICD group (48-month Kaplan-Meier estimates 19.2% and 11.5%; P=0.02). Patients in the S-ICD group had a total of 254 shocks, compared with 228 shocks in the TV-ICD group (P=0.68). First shock efficacy was 93.8% in the S-ICD group and 91.6% in the TV-ICD group (P=0.40). The first antitachycardia pacing attempt successfully terminated 46% of all monomorphic ventricular tachycardias, but accelerated the arrhythmia in 9.4%. Ten patients with S-ICD experienced 13 electrical storms, versus 18 patients with TV-ICD with 19 electrical storms. Patients with appropriate therapy had an almost 2-fold increased relative risk of electrical storms in the TV-ICD group compared with the S-ICD group (P=0.05). CONCLUSIONS: In this trial, no difference was observed in shock efficacy of S-ICD compared with TV-ICD. Although patients in the S-ICD group were more likely to receive an ICD shock, the total number of appropriate shocks was not different between the 2 groups. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01296022.

Subcutaneous or Transvenous Defibrillator Therapy.

BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (ICD) was designed to avoid complications related to the transvenous ICD lead by using an entirely extrathoracic placement. Evidence comparing these systems has been based primarily on observational studies. METHODS: We conducted a noninferiority trial in which patients with an indication for an ICD but no indication for pacing were assigned to receive a subcutaneous ICD or transvenous ICD. The primary end point was the composite of device-related complications and inappropriate shocks; the noninferiority margin for the upper boundary of the 95% confidence interval for the hazard ratio (subcutaneous ICD vs. transvenous ICD) was 1.45. A superiority analysis was prespecified if noninferiority was established. Secondary end points included death and appropriate shocks. RESULTS: A total of 849 patients (426 in the subcutaneous ICD group and 423 in the transvenous ICD group) were included in the analyses. At a median follow-up of 49.1 months, a primary end-point event occurred in 68 patients in the subcutaneous ICD group and in 68 patients in the transvenous ICD group (48-month Kaplan-Meier estimated cumulative incidence, 15.1% and 15.7%, respectively; hazard ratio, 0.99; 95% confidence interval [CI], 0.71 to 1.39; P = 0.01 for noninferiority; P = 0.95 for superiority). Device-related complications occurred in 31 patients in the subcutaneous ICD group and in 44 in the transvenous ICD group (hazard ratio, 0.69; 95% CI, 0.44 to 1.09); inappropriate shocks occurred in 41 and 29 patients, respectively (hazard ratio, 1.43; 95% CI, 0.89 to 2.30). Death occurred in 83 patients in the subcutaneous ICD group and in 68 in the transvenous ICD group (hazard ratio, 1.23; 95% CI, 0.89 to 1.70); appropriate shocks occurred in 83 and 57 patients, respectively (hazard ratio, 1.52; 95% CI, 1.08 to 2.12). CONCLUSIONS: In patients with an indication for an ICD but no indication for pacing, the subcutaneous ICD was noninferior to the transvenous ICD with respect to device-related complications and inappropriate shocks. (Funded by Boston Scientific; PRAETORIAN ClinicalTrials.gov number, NCT01296022.).