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.

Performance of Ambulatory Electrocardiographic Data for Prediction of Stroke and Heart Failure Events.

Background: Despite clear associations between arrhythmia burden and cardiovascular risk, clinical risk scores that predict cardiovascular events do not incorporate individual-level arrhythmia characteristics from long-term continuous monitoring (LTCM). Objectives: This study evaluated the performance of risk models that use data from LTCM and patient claims for prediction of heart failure (HF) and ischemic stroke. Methods: We retrospectively analyzed features extracted from up to 14 days of LTCM electrocardiogram (ECG) data linked to patient-level claims data for 320,974 Medicare beneficiaries who underwent ZioXT ambulatory monitoring. We created predictive models for HF hospitalization, stroke hospitalization, and new-onset HF within 1 year using LASSO Cox regression for variable selection among ambulatory ECG variables and components of the CHA2DS2-VASc score. Results: A model that included components of the CHA2DS2-VASc and all ambulatory ECG variables had greater discrimination for HF hospitalization (C-statistic 0.85, 95% CI: 0.84-0.86) than the CHA2DS2-VASc (C-statistic 0.73, 95% CI: 0.72-0.74), but performed similarly to the CHA2DS2-VASc for prediction of stroke hospitalization (C-statistic 0.75 [95% CI: 0.74-0.77] vs 0.71 [95% CI: 0.70-0.72], respectively). Atrial fibrillation was associated with greater risk in the most predictive models (HF hospitalization, HR: 1.53 [95% CI: 1.35-1.72]; stroke hospitalization, HR: 1.58 [95% CI: 1.30-1.93]), and premature ventricular couplets were associated with greater risk of HF hospitalization (HR: 1.54, 95% CI: 1.43-1.65). Conclusions: The CHA2DS2-VASc performed modestly for prediction of stroke and HF events; predictive ability improved significantly with addition of LTCM ECG covariates. The presence of atrial fibrillation and ventricular ectopy on 14-day LTCM were strongly associated with HF events.

Design and Rationale of a Pragmatic Randomized Clinical Trial of Early Dronedarone versus Usual Care to Change and Improve Outcomes in Persons with First-Detected Atrial Fibrillation - The CHANGE AFIB Study.

BACKGROUND: While there are several completed clinical trials that address treatment strategies in patients with symptomatic and recurrent atrial fibrillation (AF), there are no randomized clinical trials that address first-line rhythm control of new-onset AF. Recent data suggest that early initiation of rhythm control within 1 year can improve outcomes. METHODS: In this open-label pragmatic clinical trial nested within the Get With The Guidelines Atrial Fibrillation registry, approximately 3,000 patients with first-detected AF will be enrolled at approximately 200 sites. Participants will be randomized (1:1) to treatment with dronedarone in addition to usual care versus usual care alone. The primary endpoint will be time to first cardiovascular (CV) hospitalization or death from any cause through 12 months from randomization. Secondary endpoints will include a WIN ratio (all-cause death, ischemic stroke or systemic embolism, heart failure hospitalization, acute coronary hospitalization), CV hospitalization, and all-cause mortality. Patient reported outcomes will be analyzed based on change in Atrial Fibrillation Effect on Quality of Life (AFEQT) and change in Mayo AF-Specific Symptom Inventory (MAFSI) from baseline to 12 months. CONCLUSION: CHANGE AFIB will determine if treatment with dronedarone in addition to usual care is superior to usual care alone for the prevention of CV hospitalization or death from any cause in patients with first-detected AF. The trial will also determine whether initiation of rhythm control at the time of first-detected AF affects CV events or improves patient reported outcomes. CLINICALTRIALS: GOV #: - NCT05130268.

Assessment of Antitachycardia Pacing in Primary Prevention Patients: The APPRAISE ATP Randomized Clinical Trial.

Importance: The emergence of novel programming guidelines that reduce premature and inappropriate therapies along with the availability of new implantable cardioverter-defibrillator (ICD) technologies lacking traditional endocardial antitachycardia pacing (ATP) capabilities requires the reevaluation of ATP as a first strategy in terminating fast ventricular tachycardias (VTs) in primary prevention ICD recipients. Objective: To assess the role of ATP in terminating fast VTs in primary prevention ICD recipients with contemporary programming. Design, Setting, and Participants: This global, prospective, double-blind, randomized clinical trial had an equivalence design with a relative margin of 35%. Superiority tests were performed at interim analyses and the final analysis if equivalence was not proven. Patients were enrolled between September 2016 and April 2021 at 134 sites in 8 countries, with the last date of follow-up on July 6, 2023. Patients were required to have an indication for a primary prevention ICD, including left ventricular ejection fraction less than or equal to 35%. Interventions: Patients were randomized in a 1:1 ratio to receive ATP plus shock vs shock only. Main Outcomes and Measures: The primary end point was time to first all-cause shock. Secondary end points included time to first appropriate shock, time to first inappropriate shock, all-cause mortality, and the composite of time to first all-cause shock plus all-cause mortality. Results: A total of 2595 patients were randomized (mean age, 63.9 years; 22.4% were females). At a mean follow-up of 38 months, first all-cause shock occurred in 129 participants in the ATP plus shock group and 178 participants in the shock only group. The hazard ratio (HR) for the primary end point was 0.72 (95.9% CI, 0.57-0.92), with P = .005 for superiority of the ATP plus shock group over the shock only group. During follow-up in an intention-to-treat analysis, the total shock burden per 100 patient-years was not statistically different, at 12.3 and 14.9, respectively (P = .70). Conclusions and Relevance: The use of a single burst of ATP prior to shock in primary prevention ICD recipients with modern ICD detection programming prolonged the time to first all-cause ICD shock. Trial Registration: ClinicalTrials.gov Identifier: NCT02923726.

Transvenous extraction of conduction system and lumenless pacing leads.

INTRODUCTION: Conduction system pacing (CSP), often accomplished with lumenless pacing leads, is increasingly employed to achieve physiologic ventricular activation. There are limited data on the extraction of these leads. The objective of this study was to describe the safety and efficacy of extraction of CSP pacing leads and compare outcomes with extraction of non-CSP lumenless leads. METHODS: Patients undergoing CSP/non-CSP lumenless lead removal were included. Outcomes of interest included rates of complete procedural success, complications, and successful reimplantation. RESULTS: Overall, 23 patients were included (n = 14 with CSP and n = 9 with non-CSP lumenless leads implanted in the right atrium, right ventricle, or septum). The mean age was 52.7 ± 24.0 years, 30% were female, and the mean lead age was 4.5 ± 4.4 years. The complete procedural success rate was 100%. One serious complication occurred in the non-CSP group but was unrelated to the lead of interest. Manual traction alone was successful in 57% of CSP cases (mean lead age 2.4 ± 1.7 years) and in 11% of non-CSP cases (mean lead age 7.9 ± 5.3 years). Laser sheaths were used in 43% of CSP cases and 89% of non-CSP cases; rotational cutting tools were used in no CSP cases and in 33% of non-CSP cases. Reimplantation in the conduction system was attempted with a left bundle branch pacing lead and successful in 80% (n = 4/5). CONCLUSION: Extraction of CSP and non-CSP lumenless leads is feasible with a high success rate and a good safety profile. CSP reimplantation after extraction is also feasible with good electrical performance.

Performance of Atrial Fibrillation Burden Trends for Stroke Risk Stratification.

BACKGROUND: Atrial fibrillation (AF) is associated with an increased risk of stroke, yet the limitations of conventional monitoring have restricted our understanding of AF burden risk thresholds. Predictive algorithms incorporating continuous AF burden measures may be useful for predicting stroke. This study evaluated the performance of temporal AF burden trends as predictors of stroke from a large cohort with insertable cardiac monitors. METHODS: Using deidentified data from Optum Clinformatics Data Mart (2007-2019) linked with the Medtronic CareLink insertable cardiac monitor database, we identified patients with an insertable cardiac monitor for AF management (n=1197), suspected AF (n=1611), and cryptogenic stroke (n=2205). Daily AF burden was transformed into simple moving averages, and temporal AF burden trends were defined as the comparison of unique simple moving average pairs. Classification trees were used to predict ischemic stroke, and AF burden significance was quantified using bootstrapped mean variable importance. RESULTS: Of 5013 patients (age, 69.2±11.7 years; 50% male; CHA2DS2-VASc, 3.7±1.9) who met inclusion criteria, 869 had an ischemic stroke over 2 409 437 days total follow-up. Prior stroke or transient ischemic attack (variable importance, 13.13) was the number 1 predictor of future stroke followed by no prior diagnosis of AF (7.35) and AF burden trends in follow-up (2.59). Temporal proximity of AF and risk of stroke differed by device indication (simple moving averages: AF management, <8 days and suspected AF and cryptogenic stroke, 8-21 days). Together, baseline characteristics and AF burden trends performed optimally for the area under the receiver operating characteristic curve (0.73), specificity (0.70), and relative risk (5.00). CONCLUSIONS: AF burden trends may provide incremental prognostic value as leading indicators of stroke risk compared with conventional schemes.

Using Atrial Fibrillation Burden Trends and Machine Learning to Predict Near-Term Risk of Cardiovascular Hospitalization.

BACKGROUND: Atrial fibrillation is associated with an increased risk of cardiovascular hospitalization (CVH), which may be triggered by changes in daily burden. Machine learning of dynamic trends in atrial fibrillation burden, as measured by insertable cardiac monitors (ICMs), may be useful in predicting near-term CVH. METHODS: Using Optum's deidentified Clinformatics Data Mart Database (2007-2019), linked with the Medtronic CareLink ICM database, we identified patients with >1 days of ICM-detected atrial fibrillation. ICM-detected diagnostic parameters were transformed into simple moving averages over different periods for daily follow-up. A diagnostic trend was defined as the comparison of 2 simple moving averages of different periods for each diagnostic parameter. CVH was defined as any hospital, emergency department, or ambulatory surgical center encounter with a cardiovascular diagnosis-related group or diagnosis code. Machine learning was used to determine which diagnostic trends could best predict patient risk 5 days before CVH. RESULTS: A total of 2616 patients with ICMs met the inclusion criteria (71±11 years; 55% male). Among them, 1998 (76%) had a planned or unplanned CVH over 605 363 days. Machine learning revealed distinct groups: (A) sinus rhythm (reference), (B) below-average burden, (C) above-average burden, and (D) above-average burden with decreasing patient activity. The relative risk was increased in all groups versus the reference (B, 4.49 [95% CI, 3.74-5.40]; C, 8.41 [95% CI, 7.00-10.11]; D, 11.15 [95% CI, 9.10-13.65]), including a 21% increase in CVH detection over prespecified burden thresholds of duration (≥1 hour) and quantity (≥5%). The area under the receiver operating characteristic curve increased from 0.55 when using hourly burden amounts to 0.66 when using burden trends and decreasing patient activity (P<0.001), a 20% increase in predictive power. CONCLUSIONS: Trends in atrial fibrillation were strongly associated with near-term CVH, especially above-average burden coupled with low patient activity. This approach could provide actionable information to guide treatment and reduce CVH.

AN INTERNATIONAL PHYSICIAN SURVEY OF CURRENT ABLATION PRACTICES IN ATRIAL FIBRILLATION: AN AIM-AF SUBSTUDY.

BACKGROUND: Practice guidelines recommend Ablation (ABL) in atrial fibrillation (AF) for rhythm control; guidance for antiarrhythmic drugs (AADs) post-ablation is limited. OBJECTIVE: To understand AAD and ABL practices in USA and Europe. METHODS: An online survey of experienced cardiologists (CDs, n=360) and interventional electrophysiologists (EPs, n=269) was conducted. AAD and ABL related survey questions and responses were analyzed. RESULTS: ABL was preferred more often as first-line AF therapy (Rx) by US CDs/EPs (p<.001). ABL was selected to avoid AAD Rx by 46% (50% CDs, 40% EPs), prevent AF progression by 41% (36% CDs, 47% EPs) and for superior efficacy by 28% (27% CDs, 30% EPs), ABL was employed by 9% in asymptomatic AF (9% CDs, 10% EPs), by 14% in subclinical AF (13% CDs, 14% EPs), by 17% for first AF event (15% CDs, 18% EPs). Primary ABL was preferred in heart failure by 38%. Co-morbidities, age and left atrial size were limitations for ABL by 48%, 40% and 38%, respectively. AADs were used after ABL for AF/ atrial tachycardia (AT) prophylaxis by 34% for 3-6 months and 29% for 1-2 months. AADs were given for a single AF recurrence by 34%, bridging to re-ablation by 32%, and long-term Rx by 34%. AF/AT post-ABL was most often managed with amiodarone (42-48%). CONCLUSION: ABL was frequently preferred over AADs in symptomatic AF but was notably also used for asymptomatic and subclinical AF. Post-ABL AAD Rx for AF prophylaxis or recurrence was frequent with empiric amiodarone being the most often selected AAD.

Asundexian versus Apixaban in Patients with Atrial Fibrillation.

BACKGROUND: Stroke prevention with direct-acting oral anticoagulant agents in patients with atrial fibrillation confers a risk of bleeding and limits their use. Asundexian, an activated factor XI (XIa) inhibitor, is an oral anticoagulant that may prevent strokes with less bleeding. METHODS: In a phase 3, international, double-blind trial, we randomly assigned high-risk patients with atrial fibrillation in a 1:1 ratio to receive asundexian at a dose of 50 mg once daily or standard-dose apixaban. The primary efficacy objective was to determine whether asundexian is at least noninferior to apixaban for the prevention of stroke or systemic embolism. The primary safety objective was to determine whether asundexian is superior to apixaban with respect to major bleeding events. RESULTS: A total of 14,810 randomly assigned patients were included in the intention-to-treat population. The mean (±SD) age of the patients was 73.9±7.7 years, 35.2% were women, 18.6% had chronic kidney disease, 18.2% had a previous stroke or transient ischemic attack, 16.8% had received oral anticoagulants for no more than 6 weeks, and the mean CHA2DS2-VASc score (range, 0 to 9, with higher scores indicating a greater risk of stroke) was 4.3±1.3. The trial was stopped prematurely at the recommendation of the independent data monitoring committee. Stroke or systemic embolism occurred in 98 patients (1.3%) assigned to receive asundexian and in 26 (0.4%) assigned to receive apixaban (hazard ratio, 3.79; 95% confidence interval [CI], 2.46 to 5.83). Major bleeding occurred in 17 patients (0.2%) who received asundexian and in 53 (0.7%) who received apixaban (hazard ratio, 0.32; 95% CI, 0.18 to 0.55). The incidence of any adverse event appeared to be similar in the two groups. CONCLUSIONS: Among patients with atrial fibrillation at risk for stroke, treatment with asundexian at a dose of 50 mg once daily was associated with a higher incidence of stroke or systemic embolism than treatment with apixaban in the period before the trial was stopped prematurely. There were fewer major bleeding events with asundexian than with apixaban during this time. (Funded by Bayer; OCEANIC-AF ClinicalTrials.gov number, NCT05643573; EudraCT number, 2022-000758-28.).

Factors associated with stellate ganglion block success in recurrent ventricular arrhythmias.

AIMS: One treatment option for refractory ventricular arrythmias is stellate ganglion block (SGB). We examined differences in SGB success by patient and arrhythmia characteristics and predictors of successful SGB. METHODS AND RESULTS: This was a multicenter analysis of patients treated for refractory ventricular arrythmias in the Czech Republic and the United States. The primary outcome was absence of ventricular arrythmias at 24 h post SGB. SGB effectiveness was examined according to aetiology of cardiomyopathy, arrhythmia type, laterality of SGB, presence of inotropes, and presence of mechanical circulatory support. Binary logistic regression was used to examine variables associated with the primary outcome. In total there were 117 patients with refractory ventricular arrythmias treated with SGB. Overall, the mean age was 63.5 ± 11.0 years, majority of patients were male (94.0%), White (87.2%), and had an implantable cardioverter defibrillator in situ (70.1%). There were no differences in efficacy of SGB based on aetiology of cardiomyopathy (P = 0.623), arrhythmia type (0.852), laterality of block (P = 0.131), and presence of inotropes (P = 0.083). Multivariable analysis demonstrated that increased age was associated with decreased odds of SGB success (odds ratio: 0.96, confidence interval: 0.92-0.99, P = 0.039) whereas increased left ventricular ejection fraction trended towards increased odds of SGB success (odds ratio: 1.05, confidence interval: 0.995-1.11, P = 0.077). CONCLUSIONS: In this multicentre experience, SGB was similarly effective despite the aetiology of cardiomyopathy, type of arrhythmia, laterality, and inotropic or mechanical support. SGB was less effective for the suppression of ventricular arrythmias at 24 h for the elderly.

Anticoagulation Alone vs Anticoagulation Plus Aspirin or DAPT Following Left Atrial Appendage Occlusion.

BACKGROUND: The prevalence of and outcomes associated with different antithrombotic strategies after left atrial appendage occlusion (LAAO) are not well described. OBJECTIVES: This study sought to evaluate patterns of antithrombotic medication strategies at discharge following LAAO with the Watchman FLX device in real-world practice and to compare the risk of adverse events among the different antithrombotic regimens. METHODS: The authors evaluated patients in the NCDR (National Cardiovascular Data Registry) LAAO Registry who underwent LAAO with the second-generation LAA closure device between 2020 and 2022. They grouped patients by mutually exclusive discharge antithrombotic strategies and compared the rates of adverse events at 45 days and 6 months using multivariable Cox proportional hazards regression. RESULTS: Among 53,878 patients undergoing successful LAAO with the second-generation LAA closure device, the most common antithrombotic discharge regimens were direct oral anticoagulant (DOAC) plus aspirin (48.3%), DOAC alone (22.6%), dual antiplatelet therapy (8.1%), warfarin plus aspirin (7.7%), and DOAC plus P2Y12 inhibitor (4.9%). In multivariate analysis, DOAC alone had a lower rate of major adverse events and major bleeding at 45 days of follow-up compared with DOAC plus aspirin (major adverse events: HR: 0.78; 95% CI: 0.68-0.91; major bleeding: HR: 0.69; 95% CI: 0.60-0.80). These differences persisted at 6 months. Warfarin without aspirin also showed lower rates of major bleeding at both time points. No differences were seen in stroke/transient ischemic attack or device-related thrombus. CONCLUSIONS: In real-world U.S. practice, discharge on DOAC alone or warfarin alone was associated with a lower rate of adverse events compared with DOAC plus aspirin.

Discordant Treatment Goals for Patients With Atrial Fibrillation and Clinical Trials Metrics.

BACKGROUND: Most clinical trials define successful atrial fibrillation (AF) treatment as no AF episodes longer than 30 seconds. Yet, there has been minimal study of how patients define successful treatment and whether their perspectives align with trial outcomes. OBJECTIVES: Survey patients with AF to identify: 1) what aspect of AF is most important to address (frequency, duration, or severity of AF episodes); 2) what AF burden would be considered acceptable to consider treatment successful; and 3) to establish patient preferences for successful treatment thresholds for a validated patient-reported outcome (PRO) score. METHODS: We surveyed patients receiving active care for AF at a single tertiary care center modeled after the Toronto AF Severity Scale (AFSS). The survey consisted of current and "successful treatment" AF frequency, burden, and symptom domains; and baseline socioeconomic information. RESULTS: Of 7,000 invitations, 852 individuals completed the survey (12% response) with a mean age of 65 ± 13 years, 36.5% were female, and they had a mean CHA2DS2-VAsc score of 2.9 ± 1.9. Overall, 114 (13%) selected a decrease in AF episode duration as their top treatment priority, 505 (59%) episode frequency, and 230 (27%) episode severity. Overall, 207 (24%) patients would only consider a treatment successful if they never had AF again, whereas 645 (76%) patients considered success to be fewer AF episodes. A total of 341 (40%) patients would only consider a treatment successful if AF episodes lasted less than a few minutes, whereas 509 (60%) patients would accept AF episodes lasting >30 minutes. An AFSS symptom score ≤5 was considered a good outcome by 80% of respondents. CONCLUSIONS: Patients prioritize decreased AF frequency over improvements in severity or duration, and an AFSS ≤5 would be a reasonable outcome of AF treatment. Most patients would consider treatment successful if they had more than 1 AF episode lasting longer than 30 seconds. Future clinical trial design should consider patients' perspectives when designing outcomes.

Outcomes With the WATCHMAN FLX in Everyday Clinical Practice From the NCDR Left Atrial Appendage Occlusion Registry.

BACKGROUND: PINNACLE FLX (Protection Against Embolism for Nonvalvular AF Patients: Investigational Device Evaluation of the WATCHMAN FLX LAA Closure Technology) demonstrated improved outcomes and low incidence of adverse events with the WATCHMAN FLX device in a controlled setting. The National Cardiovascular Disease Registry's Left Atrial Appendage Occlusion Registry was utilized to assess the safety and effectiveness of WATCHMAN FLX in contemporary clinical practice in the United States. METHODS: The WATCHMAN FLX Device Surveillance Post Approval Analysis Plan used data from the Left Atrial Appendage Occlusion registry to identify patients undergoing WATCHMAN FLX implantation between August 2020 and September 2022. The key safety end point was defined as all-cause death, ischemic stroke, systemic embolism, or device or procedure-related events requiring open cardiac surgery or major endovascular intervention between device implantation and hospital discharge. Major adverse events were reported at hospital discharge, 45 days, and 1 year. RESULTS: Among 97 185 patients in the Left Atrial Appendage Occlusion registry undergoing WATCHMAN FLX, successful implantation occurred in 97.5% (n=94 784) of patients. The key safety end point occurred in 0.45% of patients. At 45 days post-procedure, all-cause death occurred in 0.81% patients, ischemic stroke in 0.23%, major bleeding in 3.1%, pericardial effusion requiring intervention in 0.50%, device-related thrombus in 0.44%, and device embolism in 0.04% patients. No peri-device leak was observed in 83.1% of patients at 45 days. At 1 year, the rate of all-cause death was 8.2%, the rate of any stroke was 1.5% (ischemic stroke, 1.2%), and major bleeding occurred in 6.4% of patients. CONCLUSIONS: In a large contemporary cohort of patients with the WATCHMAN FLX device, the rates of implant success and clinical outcomes through 1 year were comparable with the PINNACLE FLX study, demonstrating that favorable outcomes achieved in the pivotal approval study can be replicated in routine clinical practice.

Ineffective cardiac resynchronization pacing is associated with poor outcomes in a nationwide cohort analysis.

BACKGROUND: Delivery of cardiac resynchronization therapy (CRT) requires left ventricular myocardial capture to achieve clinical benefits. OBJECTIVE: We sought to determine whether ineffective pacing affects survival. METHODS: Ineffective ventricular pacing (VP) was defined as the difference between the percentage of delivered CRT (%VP) and the percentage of effective CRT in CRT devices. Using the Optum de-identified electronic health record data set and Medtronic CareLink data warehouse, we identified patients implanted with applicable devices with at least 30 days of follow-up. Kaplan-Meier and Cox proportional hazards models assessed the impact of %VP and % ineffective VP on survival. RESULTS: Among 7987 patients with 2.1 ± 1.0 years of follow-up, increasing ineffective VP was associated with decreasing survival: the highest observed survival was in the quartile with <0.08% ineffective VP and the lowest survival was in the quartile with >1.47% ineffective VP (85.1% vs 75.7% at 3 years; P < .001). As expected, patients with more than the median %VP of 97.7% had better survival than did patients with <97.7% VP (84.2% vs 77.8%; P < .001). However, patients who had >97.7% VP but >2% ineffective VP had similar survival to patients with <97.7% VP but ≤2% ineffective VP (81.6% vs 79.4%; P = .54). A multivariable Cox proportional hazards model demonstrated that <97.7% VP (adjusted hazard ratio 1.29; 95% confidence interval 1.14-1.46; P < .001) and >2% ineffective VP (hazard ratio 1.35; 95% confidence interval 1.18-1.54; P < .001) were both significantly associated with decreased survival. CONCLUSION: Ineffective VP is associated with decreased survival. In addition to maximizing the percentage of delivered CRT pacing, every effort should be made to minimize ineffective VP.

Association between COVID-19 vaccination and atrial arrhythmias in individuals with cardiac implantable electronic devices.

INTRODUCTION: The impact of mRNA-based coronavirus disease-2019 (COVID-19) vaccines on atrial arrhythmias (AA) and ventricular arrhythmias incidence is unknown. METHODS: BIOTRONIK Home Monitoring data and Medicare Claims data were utilized to identify individuals implanted with a cardiac implantable electronic device (CIED) between 2010 and 2020 who received one or more doses of COVID-19 vaccine in 2021. The burden of AA (%) in the 3 months postvaccination was compared to those noted in the preceding 3 months using the Wilcoxon signed rank test. Sub-analyses comparing the effects of the influenza vaccine against the COVID-19 vaccine were also evaluated for individuals who received the influenza vaccine in 2020. A 1:1 propensity score match comparison between COVID-19 vaccine and non-vaccinated patients was also performed. RESULTS: First and second doses of the COVID-19 vaccine were administered to 7757 and 6579 individuals with a CIED (age 76.2 ± 9.0 years, 49% males), respectively. While a small but statistically significant increase in the burden of AA was noted in the 3 months postvaccination compared to the preceding 3 months after the first dose of the COVID-19 vaccine (0.43 ± 9.04%, p = .028) a similar rise in AA was found following the influenza vaccine and for matched patients who did not receive the COVID-19 vaccine. No significant difference in device therapies was seen pre- and postvaccination. CONCLUSIONS: Though we report a small but significant increase in the number of CIED-detected AAs following vaccination for COVID-19 over a 3-month window, we believe these results correlate more with time and the progressive nature of AF rather than the vaccine itself. While these data should not dissuade from the use of these vaccines, increased vigilance and prompt treatment of AF is required for high-risk groups, specifically males over 70 years of age, following vaccination.

Predictors of Shock-Reduction Programming and Its Impact on Implantable Cardioverter-Defibrillator Therapies and Mortality: The CERTITUDE Registry.

BACKGROUND: Shock-reduction implantable cardioverter-defibrillator programming (SRP) was associated with fewer therapies and improved survival in randomized controlled trials, but real-world studies investigating SRP and associated outcomes are limited. METHODS AND RESULTS: The BIOTRONIK CERTITUDE registry was linked with the Medicare database. We included all patients with an implantable cardioverter-defibrillator implanted between August 22, 2012 and September 30, 2021 in the United States. SRP was defined as programming to either a therapy rate cutoff ≥188 beats per minute or number of intervals to detection ≥30/40 for treatment. Among 6781 patients (mean 74±9 years; 27% women), 3393 (50%) had SRP. Older age, secondary prevention indication, and device implantation in the southern or western United States were associated with lower use of SRP. The cumulative incidence rate of implantable cardioverter-defibrillator shocks was lower in the SRP group (5.1% shocks/patient year) compared with the non-SRP group (7.2% shocks/patient year) (adjusted hazard ratio [HR], 0.83 [95% CI, 0.73-0.96]; P=0.005). Over a median follow-up of 2.9 years, 739 deaths occurred in the SRP group and 822 deaths occurred in the non-SRP group (adjusted HR, 0.97 [95% CI, 0.88-1.07]; P=0.569). SRP was associated with a lower all-cause mortality among patients without ischemic heart disease compared with patients with ischemic heart disease (adjusted HR, 0.64 [95% CI, 0.48-0.87] versus adjusted HR, 1.02 [95% CI, 0.92-1.14]; Pinteraction=0.004). CONCLUSIONS: Adoption of SRP is low in real-world clinical practice. Age, clinical variables, and geographic factors are associated with use of SRP. In this study, SRP-associated decrease in mortality was limited to patients without ischemic heart disease.

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.

Machine Learning of Cardiac Anatomy and the Risk of New-Onset Atrial Fibrillation After TAVR.

BACKGROUND: New-onset atrial fibrillation (NOAF) occurs in 5% to 15% of patients who undergo transfemoral transcatheter aortic valve replacement (TAVR). Cardiac imaging has been underutilized to predict NOAF following TAVR. OBJECTIVES: The objective of this analysis was to compare and assess standard, manual echocardiographic and cardiac computed tomography (cCT) measurements as well as machine learning-derived cCT measurements of left atrial volume index and epicardial adipose tissue as risk factors for NOAF following TAVR. METHODS: The study included 1,385 patients undergoing elective, transfemoral TAVR for severe, symptomatic aortic stenosis. Each patient had standard and machine learning-derived measurements of left atrial volume and epicardial adipose tissue from cardiac computed tomography. The outcome of interest was NOAF within 30 days following TAVR. We used a 2-step statistical model including random forest for variable importance ranking, followed by multivariable logistic regression for predictors of highest importance. Model discrimination was assessed by using the C-statistic to compare the performance of the models with and without imaging. RESULTS: Forty-seven (5.0%) of 935 patients without pre-existing atrial fibrillation (AF) experienced NOAF. Patients with pre-existing AF had the largest left atrial volume index at 76.3 ± 28.6 cm3/m2 followed by NOAF at 68.1 ± 26.6 cm3/m2 and then no AF at 57.0 ± 21.7 cm3/m2 (P < 0.001). Multivariable regression identified the following risk factors in association with NOAF: left atrial volume index ≥76 cm2 (OR: 2.538 [95% CI: 1.165-5.531]; P = 0.0191), body mass index <22 kg/m2 (OR: 4.064 [95% CI: 1.500-11.008]; P = 0.0058), EATv (OR: 1.007 [95% CI: 1.000-1.014]; P = 0.043), aortic annulus area ≥659 mm2 (OR: 6.621 [95% CI: 1.849-23.708]; P = 0.004), and sinotubular junction diameter ≥35 mm (OR: 3.891 [95% CI: 1.040-14.552]; P = 0.0435). The C-statistic of the model was 0.737, compared with 0.646 in a model that excluded imaging variables. CONCLUSIONS: Underlying cardiac structural differences derived from cardiac imaging may be useful in predicting NOAF following transfemoral TAVR, independent of other clinical risk factors.

Procedure Volume and Outcomes With WATCHMAN Left Atrial Appendage Occlusion.

BACKGROUND: Procedure volumes are associated with outcomes for many cardiovascular procedures, leading to guidelines on minimum volume thresholds for certain procedures; however, the volume-outcome relationship with left atrial appendage occlusion is poorly understood. As such, we sought to determine the relationship between hospital and physician volume and WATCHMAN left atrial appendage occlusion procedural success overall and with the new generation WATCHMAN FLX device. METHODS: We performed an analysis of WATCHMAN procedures (January 2019 to October 2021) from the National Cardiovascular Data Registry LAAO Registry. Three-level hierarchical generalized linear models were used to assess the adjusted relationship between procedure volume and procedural success (device released with peridevice leak <5 mm, no in-hospital major adverse events). RESULTS: Among 87 480 patients (76.2±8.0 years; 58.8% men; mean CHA2DS2-VASc score, 4.8±1.5) from 693 hospitals, the procedural success rate was 94.2%. With hospital volume Q4 (greatest volume) as the reference, the likelihood of procedural success was significantly less among Q1 (odds ratio [OR], 0.66 [CI, 0.57-0.77]) and Q2 (OR, 0.78 [CI, 0.69-0.90]) but not Q3 (OR, 0.95 [CI, 0.84-1.07]). With physician volume Q4 (greatest volume) as the reference, the likelihood of procedural success was significantly less among Q1 (OR, 0.72 [CI, 0.63-0.82]), Q2 (OR, 0.79 [CI, 0.71-0.89]), and Q3 (OR, 0.88 [CI, 0.79-0.97]). Among WATCHMAN FLX procedures, there was attenuation of the volume-outcome relationships, with statistically significant but modest absolute differences of only ≈1% across volume quartiles. CONCLUSIONS: In this contemporary national analysis, greater hospital and physician WATCHMAN volumes were associated with increased procedure success. The WATCHMAN FLX transition was associated with increased procedural success and less heterogeneity in outcomes across volume quartiles. These findings indicate the importance of understanding the volume-outcome relationship for individual left atrial appendage occlusion devices.