Pulmonary Vein Isolation With or Without Left Atrial Appendage Ligation in Atrial Fibrillation: The aMAZE Randomized Clinical Trial.

Importance: Left atrial appendage elimination may improve catheter ablation outcomes for atrial fibrillation. Objective: To assess the safety and effectiveness of percutaneous left atrial appendage ligation adjunctive to catheter pulmonary vein isolation for nonparoxysmal atrial fibrillation. Design, Setting, and Participants: This multicenter, prospective, open-label, randomized clinical trial evaluated the safety and effectiveness of percutaneous left atrial appendage ligation adjunctive to planned pulmonary vein isolation for nonparoxysmal atrial fibrillation present for less than 3 years. Eligible patients were randomized in a 2:1 ratio to undergo left atrial appendage ligation and pulmonary vein isolation or pulmonary vein isolation alone. Use of a 2:1 randomization ratio was intended to provide more device experience and safety data. Patients were enrolled from October 2015 to December 2019 at 53 US sites, with the final follow-up visit on April 21, 2021. Interventions: Left atrial appendage ligation plus pulmonary vein isolation compared with pulmonary vein isolation alone. Main Outcomes and Measures: A bayesian adaptive analysis was used for primary end points. Primary effectiveness was freedom from documented atrial arrythmias of greater than 30 seconds duration 12 months after undergoing pulmonary vein isolation. Rhythm was assessed by Holter monitoring at 6 and 12 months after pulmonary vein isolation, symptomatic event monitoring, or any electrocardiographic tracing obtained through 12 months after pulmonary vein isolation. Primary safety was a composite of predefined serious adverse events compared with a prespecified 10% performance goal 30 days after the procedure. Left atrial appendage closure was evaluated through 12 months after pulmonary vein isolation. Results: Overall, 404 patients were randomized to undergo left atrial appendage ligation plus pulmonary vein isolation and 206 were randomized to undergo pulmonary vein isolation alone. Primary effectiveness was 64.3% with left atrial appendage ligation and pulmonary vein isolation and 59.9% with pulmonary vein isolation only (difference, 4.3% [bayesian 95% credible interval, -4.2% to 13.2%]; posterior superiority probability, 0.835), which did not meet the statistical criterion to establish superiority (0.977). Primary safety was met, with a 30-day serious adverse event rate of 3.4% (bayesian 95% credible interval, 2.0% to 5.0%; posterior probability, 1.0) which was less than the prespecified threshold of 10%. At 12 months after pulmonary vein isolation, complete left atrial appendage closure (0 mm residual communication) was observed in 84% of patients and less than or equal to 5 mm residual communication was observed in 99% of patients. Conclusions and Relevance: Percutaneous left atrial appendage ligation adjunctive to pulmonary vein isolation did not meet prespecified efficacy criteria for freedom from atrial arrhythmias at 12 months compared with pulmonary vein isolation alone for patients with nonparoxysmal atrial fibrillation, but met prespecified safety criteria and demonstrated high rates of closure at 12 months. Trial Registration: ClinicalTrials.gov Identifier: NCT02513797.

Outcomes of convergent atrial fibrillation ablation with continuous rhythm monitoring.

BACKGROUND: Outcomes of catheter ablation for persistent atrial fibrillation (PeAF) are suboptimal. The convergent procedure (CP) may offer improved efficacy by combining endocardial and epicardial ablation. METHODS: We reviewed 113 consecutive patients undergoing the CP at our institution. The cohort was divided into two groups based on the presence (n = 92) or absence (n = 21) of continuous rhythm monitoring (CM) following the CP. Outcomes were reported in two ways. First, using a conventional definition of any atrial fibrillation/atrial tachycardia (AF/AT) recurrence lasting >30 seconds, after a 90 day blanking period. Second, by determining AF/AT burden at relevant time points in the group with CM. RESULTS: Across the entire cohort, 88% had either persistent or long-standing persistent AF, mean duration of AF diagnosis before the CP was 5.1 ± 4.6 years, 45% had undergone at least one prior AF ablation, 31% had impaired left ventricle ejection fraction and 62% met criteria for moderate or severe left atrial enlargement. Mean duration of follow-up after the CP was 501 ± 355 days. In the entire cohort, survival free from any AF/AT episode >30 seconds at 12 months after the blanking period was 53%. However, among those in the CM group who experienced recurrences, mean burden of AF/AT was generally very low (<5%) and remained stable over the duration of follow-up. Ten patients (9%) required elective cardioversion outside the 90 day blanking period, 11 patients (9.7%) underwent repeat ablation at a mean of 229 ± 178 days post-CP and 64% were off AADs at the last follow-up. Procedural complications decreased significantly following the transition from transdiaphragmatic to sub-xiphoid surgical access: 23% versus 3.8% (P = .005) CONCLUSIONS: In a large, consecutive series of patients with predominantly PeAF, the CP was capable of reducing AF burden to very low levels (generally <5%), which appeared durable over time. Complication rates associated with the CP decreased significantly with the transition from transdiaphragmatic to sub-xiphoid surgical access. Future trials will be necessary to determine which patients are most likely to benefit from the convergent approach.

Outcomes of Micra leadless pacemaker implantation with uninterrupted anticoagulation.

BACKGROUND: Implantation of the MICRA Leadless pacemaker requires the use of a 27 French introducer, blunt delivery system and device fixation to the myocardium via nitinol tines. While prior studies have proven its safety, it is unclear whether performing this procedure with uninterrupted anticoagulation exposes patients to increased risks. We sought to investigate the feasibility and safety of continuing therapeutic anticoagulation during the periprocedural period. METHODS: We evaluated all patients undergoing MICRA placement at our institution between April 2014 and August 2018 with complete follow-up data (n = 170). Patients were stratified into two groups: those on active anticoagulation (OAC, n = 26), defined as having an International normalized ratio >2.0 or having continued a direct oral anticoagulant, and those not anticoagulated (Off-OAC, n = 144). We evaluated for a composite outcome of all major complications, including access site complications and pericardial effusion. RESULTS: OAC and Off-OAC groups had similar mean age (74 ± 13 vs 75 ± 13 years; P = .914). The OAC group had a nonsignificantly lower prevalence of end-stage renal disease (8% vs 17%; P = .375) and aspirin use (27% vs 47%; P = .131). Those in the OAC group were more likely to be on warfarin than those in the Off-OAC group (81% vs 30%; P < .001). The rate of the composite endpoint was similar between the OAC and Off-OAC groups (3.8 % vs 1.4%, respectively; P = .761). Length of stay was similar between groups (1.3 ± 2.6 vs 2.3 ± 3.4 days; P = 0.108). CONCLUSION: Continuation of therapeutic anticoagulation during MICRA implantation appears to be feasible, safe and associated with shorter hospitalization among appropriately selected individuals.

Outcomes of percutaneous vacuum-assisted debulking of large vegetations as an adjunct to lead extraction.

BACKGROUND: Consensus statements on lead extraction give consideration to open surgical removal in the setting of large vegetations, to mitigate the risk of massive embolism that may occur with percutaneous lead removal. Vacuum-assisted debulking (VD) of large vegetations as an adjunct to percutaneous lead extraction may provide an opportunity to mitigate these risks. METHODS: We retrospectively identified all patients undergoing lead extraction at our institution for endovascular infection from 2012 to 2018 and stratified them into two groups based on presence of adjunctive VD (n = 6) or without VD (no-VD, n = 39). VD was performed with the AngioVac system (Angio-Dynamics, Latham, NY, USA). RESULTS: Across the cohort, mean age was 62 ± 15 years, ejection fraction was 41 ± 16%, and 39% had end-stage renal disease on dialysis. Defibrillator systems were present in 71%, and 22% had cardiac resynchronization devices. Mean duration of the oldest extracted lead was 6.3 ± 4.9 years. There were no significant differences in baseline covariates between groups. Those in the VD group were significantly less likely to have Staphylococcus aureus as a causative organism (P = .04). In the VD group, vegetations targeted for debulking ranged in size from 1.8 to 6 cm (longest dimension). There were no operative deaths or clinically evident embolic events in either group. The overall nonfatal complication rate in the VD group was higher (33.3% vs 2.3%, P = .043). CONCLUSION: VD can be performed as an adjunct to percutaneous lead extraction with a reasonable safety profile. The relative safety and efficacy of this approach removal requires further study.

Clinical Performance of Magnetic Resonance Imaging Conditional and Nonconditional Cardiac Implantable Electronic Devices.

OBJECTIVES: This study compared risks associated with magnetic resonance imaging (MRI) in patients with non-MRI conditional and MRI conditional pacing and defibrillator systems with particular attention to clinically actionable outcomes. BACKGROUND: While recipients of new MRI conditional pacemaker and defibrillator systems may undergo MRI scanning with very low risk, safety and regulatory concerns persist regarding such scanning in recipients of non-MRI conditional systems. METHODS: Patients with any cardiac device who were referred for MRI were prospectively enrolled at a single center and underwent scanning at 1.5 Tesla. Pre- and postscan lead characteristic changes, system integrity, and symptoms were analyzed. A comparison was made between non-MRI conditional and MRI conditional devices. RESULTS: 105 patients were evaluated allowing for comparison of 97 scans with non-MRI conditional devices and 16 scans with MRI conditional devices. The cohort included those with pacemaker dependency, defibrillator, and cardiac resynchronization devices. Small, nonsignificant changes were observed in lead characteristics following scanning, and there was no significant difference when comparing non-MRI and MRI conditional devices. Lead parameter changes did not require lead revision or programming changes. No device reset, failures, or premature scan termination was observed. CONCLUSIONS: 1.5 T MRI scanning in patients with MRI conditional and non-MRI conditional cardiac devices was performed with similar, low clinical risk.

Electrogram Characteristics of Ablated and Non-Ablated Myocardium in Humans: A Comparison of Miniaturized Embedded Electrodes and Conventional Ablation Electrodes.

INTRODUCTION: Intracardiac electrogram voltage remains an important metric for radiofrequency lesion application. Embedded micro-electrodes within ablation catheters are now approved for use in humans. OBJECTIVE: This study examined electrogram characteristics of miniaturized electrode bipoles (iEGMmini ) compared to distal ablation tip bipoles (iEGMstandard ) in the setting of typical atrial flutter in humans. METHODS: This was a single-center prospective trial involving 21 patients. A total of 54 non-ablated and 56 ablated sites were analyzed offline by separate blinded observers for iEGM voltage after a clinically successful radiofrequency (RF) ablation for typical atrial flutter. Ablation sites were defined as sites that were localized anatomically within the RF lesion set and did not have atrial capture at 10 mA and 2 milliseconds. Non-ablated sites were defined as sites adjacent to or remote from the ablation lesion set with capture at 10 mA and 2 milliseconds. RESULTS: iEGMmini had greater voltages at non-ablated sites and lower voltages at ablated sites than iEGMstandard (non-ablated sites iEGMstandard 0.64 mV vs. iEGMmini 1.0 mV; ablated sites iEGMstandard 0.15 mV, iEGMmini 0.08 mV, P < 0.001). The difference for each patient between ablated and non-ablated sites was greater for iEGMmini compared to iEGMstandard (0.94 mV ± 0.57 iEGMmini vs. 0.52 mV ± 0.35 iEGMstandard , P < 0.001). Inter-observer agreement was good among all non-ablated sites and iEGMmini ablated sites, but was less robust for ablated sites using iEGMstandard . CONCLUSIONS: Imbedded mini-electrode iEGM bipoles had higher voltages in non-ablated tissue, lower voltages in ablated tissue, and significantly greater intra-patient differences between ablated and non-ablated sites. These data suggest a potential role for miniaturized electrode bipole use in RF lesion monitoring.

Outcome of Subcutaneous Implantable Cardioverter Defibrillator Implantation in Patients with End-Stage Renal Disease on Dialysis.

BACKGROUND: Although the subcutaneous ICD (S-ICD®) is an attractive alternative in patients with end-stage renal disease (ESRD), data on S-ICD outcomes in dialysis patients are lacking. METHODS: Patients with cardiomyopathy undergoing S-ICD implantation in our center were stratified by need for chronic dialysis at the time of implant. The primary endpoint was incidence of death, heart failure hospitalization or appropriate S-ICD shocks, and secondary endpoints were incidence of inappropriate shocks or implant related complications requiring surgical re-intervention. Mean follow-up was longer in the nondialysis cohort (514 ± 495 vs. 227 ± 233 days, P = 0.006), so all endpoints were analyzed using time-dependent comparisons and reported as annual event rates. RESULTS: Out of 79 S-ICD implants included in this analysis, 27 patients were on dialysis. Dialysis patients were older and more likely to be diabetic. Mean ejection fraction across the entire cohort was 26.9% without significant difference between dialysis and nondialysis groups. Although not significant, the incidence of the primary endpoint was higher in the dialysis cohort (23.8%/year vs. 10.9%/year, P = 0.317), driven primarily by a higher rate of appropriate shocks. The rate of inappropriate shocks was similar between groups (dialysis 6.0%/year vs. nondialysis 6.8%/year, P = 0.509). No patients in the dialysis cohort had complications requiring surgical re-intervention versus 6 patients in the nondialysis cohort (P = 0.086). CONCLUSIONS: Our data suggest that S-ICD implantation in dialysis patients is not associated with an excess risk of implant related complications or inappropriate shocks.

Prediction of response to cardiac resynchronization therapy using left ventricular pacing lead position and cardiovascular magnetic resonance derived wall motion patterns: a prospective cohort study.

BACKGROUND: Despite marked benefits in many heart failure patients, a considerable proportion of patients treated with cardiac resynchronization therapy (CRT) fail to respond appropriately. Recently, a "U-shaped" (type II) wall motion pattern identified by cardiovascular magnetic resonance (CMR) has been associated with improved CRT response compared to a homogenous (type I) wall motion pattern. There is also evidence that a left ventricular (LV) lead localized to the latest contracting LV site predicts superior response, compared to an LV lead localized remotely from the latest contracting LV site. METHODS: We prospectively evaluated patients undergoing CRT with pre-procedural CMR to determine the presence of type I and type II wall motion patterns and pre-procedural echocardiography to determine end systolic volume (ESV). We assessed the final LV lead position on post-procedural fluoroscopic images to determine whether the lead was positioned concordant to or remote from the latest contracting LV site. CRT response was defined as a ≥ 15% reduction in ESV on a 6 month follow-up echocardiogram. RESULTS: The study included 33 patients meeting conventional indications for CRT with a mean New York Heart Association class of 2.8 ± 0.4 and mean LV ejection fraction of 28 ± 9%. Overall, 55% of patients were echocardiographic responders by ESV criteria. Patients with both a type II pattern and an LV lead concordant to the latest contracting site (T2CL) had a response rate of 92%, compared to a response rate of 33% for those without T2CL (p = 0.003). T2CL was the only independent predictor of response on multivariate analysis (odds ratio 18, 95% confidence interval 1.6-206; p = 0.018). T2CL resulted in significant incremental improvement in prediction of echocardiographic response (increase in the area under the receiver operator curve from 0.69 to 0.84; p = 0.038). CONCLUSIONS: The presence of a type II wall motion pattern on CMR and a concordant LV lead predicts superior CRT response. Improving patient selection by evaluating wall motion pattern and targeting LV lead placement may ultimately improve the response rate to CRT.

Pulse Generator Exchange Does Not Accelerate the Rate of Electrical Failure in a Recalled Small Caliber ICD Lead.

BACKGROUND: St. Jude Riata/Riata ST defibrillator leads (St. Jude Medical, Sylmar, CA, USA) were recalled by the Food and Drug Administration in 2011 for an increased rate of failure. More than 227,000 leads were implanted and at least 79,000 patients still have active Riata leads. Studies have examined clinical predictors of lead failure in Riata leads, but none have addressed the effect of implantable cardioverter defibrillator (ICD) generator exchange on lead failure. The purpose of this study is to assess the effect of ICD generator exchange on the rate of electrical failure in the Riata lead at 1 year. METHODS: A retrospective chart review was conducted in patients who underwent implantation of a Riata/Riata ST lead at one center. Patients with a functioning Riata lead (with/without externalized conductor) at the time of ICD exchange were compared to controls with Riata leads implanted for a comparable amount of time who did not undergo generator replacement. RESULTS: Riata leads were implanted in 1,042 patients prior to the recall and 153 of these patients underwent generator exchange without lead replacement. Conductor externalization was noted in 21.5% of Riata leads in the ICD exchange cohort, which was not different from the control group (19.2%; P = 0.32). Two leads failed in the first year after generator replacement (1.5%) which did not significantly differ from the control group (2.0%; P = 0.57). At change-out, 54% received a commanded shock (18.6 ± 0.9 J) that did not result in any change in the high-voltage lead impedance (46.1 ± 1.1 ohms). CONCLUSIONS: Conductor externalization was seen frequently in our cohort of patients. ICD generator exchange did not accelerate the rate of Riata lead failure at 1 year. Although both the control and the change-out cohorts failed at a rate much greater than nonrecalled leads, generator exchange did not appear to add to the problem.

Predictors of Long-Term Survival Following Transvenous Extraction of Defibrillator Leads.

BACKGROUND: Little data exist on long-term outcomes following extraction of implantable cardioverter defibrillator (ICD) leads, particularly for noninfectious indications. We sought to identify predictors of long-term survival after ICD lead extraction. METHODS: We retrospectively reviewed ICD lead extractions at our institution (n = 508). Procedural outcomes and long-term survival were ascertained by medical records review. RESULTS: Indication for lead extraction was infection in 32.5% and lead failure in 61.8%. Mean dwell time of the oldest extracted lead was 5.1 ± 5.9 years. Complete procedural success was achieved in 96.5% of cases. Major procedure-related complications occurred in 1.6% with six periprocedural deaths. During a mean follow-up of 866 ± 798 days, survival was significantly worse among patients with infection as the indication for extraction. At 1 year after extraction, survival among those with infection was 88.2%, compared to 95.0% in the lead failure cohort (P < 0.001). Procedural failure was a significant predictor of long-term mortality, even after excluding periprocedural deaths. In multivariate models, the presence of chronic kidney disease, increased number of leads requiring extraction, lower ejection fraction, and procedural failure were predictors of mortality. CONCLUSION: Despite high rates of procedural success, infectious indication for ICD lead extraction is associated with increased long-term mortality. In contrast, among patients undergoing extraction for lead failure, long-term survival was excellent. The presence of procedural failure was a significant predictor of long-term mortality. Further studies will be necessary to better understand the mechanisms by which procedural failure may adversely impact long-term outcomes.