Recurrence After Atrial Fibrillation Ablation and Investigational Biomarkers of Cardiac Remodeling.

BACKGROUND: Recurrence after atrial fibrillation (AF) ablation remains common. We evaluated the association between recurrence and levels of biomarkers of cardiac remodeling, and their ability to improve recurrence prediction when added to a clinical prediction model. METHODS AND RESULTS: Blood samples collected before de novo catheter ablation were analyzed. Levels of bone morphogenetic protein-10, angiopoietin-2, fibroblast growth factor-23, insulin-like growth factor-binding protein-7, myosin-binding protein C3, growth differentiation factor-15, interleukin-6, N-terminal pro-brain natriuretic peptide, and high-sensitivity troponin T were measured. Recurrence was defined as ≥30 seconds of an atrial arrhythmia 3 to 12 months postablation. Multivariable logistic regression was performed using biomarker levels along with clinical covariates: APPLE score (Age >65 years, Persistent AF, imPaired eGFR [<60 ml/min/1.73m2], LA diameter ≥43 mm, EF <50%; which includes age, left atrial diameter, left ventricular ejection fraction, persistent atrial fibrillation, and estimated glomerular filtration rate), preablation rhythm, sex, height, body mass index, presence of an implanted continuous monitor, year of ablation, and additional linear ablation. A total of 1873 participants were included. A multivariable logistic regression showed an association between recurrence and levels of angiopoietin-2 (odds ratio, 1.08 [95% CI, 1.02-1.15], P=0.007) and interleukin-6 (odds ratio, 1.02 [95% CI, 1.003-1.03]; P=0.02). The area under the receiver operating characteristic curve of a model that only contained clinical predictors was 0.711. The addition of any of the 9 studied biomarkers to the predictive model did not result in a statistically significant improvement in the area under the receiver operating characteristic curve. CONCLUSIONS: Higher angiopoietin-2 and interleukin-6 levels were associated with recurrence after atrial fibrillation ablation in multivariable modeling. However, the addition of biomarkers to a clinical prediction model did not significantly improve recurrence prediction.

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.

Pulmonary Vein Myocardial Sleeve Length and its Association With Sex and 4q25/PITX2 Genotype.

BACKGROUND: Experimental evidence suggests genetic variation in 4q25/PITX2 modulates pulmonary vein (PV) myocardial sleeve length. Although PV sleeves are the main target of atrial fibrillation (AF) ablation, little is known about the association between different PV sleeve characteristics with ablation outcomes. OBJECTIVES: This study sought to evaluate the association between clinical and genetic (4q25) risk factors with PV sleeve length in humans, and to evaluate the association between PV sleeve length and recurrence after AF ablation. METHODS: In a prospective, observational study of patients undergoing de novo AF ablation, PV sleeve length was measured using electroanatomic voltage mapping before ablation. The sentinel 4q25 AF susceptibility single nucleotide polymorphism, rs2200733, was genotyped. The primary analysis tested the association between clinical and genetic (4q25) risk factors with PV sleeve length using a multivariable linear regression model. Covariates included age, sex, body mass index, height, and persistent AF. The association between PV sleeve length and atrial arrhythmia recurrence (>30 seconds) was tested using a multivariable Cox proportional hazards model. RESULTS: Between 2014 and 2019, 197 participants were enrolled (median age 63 years [IQR: 55 to 70 years], 133 male [67.5%]). In multivariable modeling, men were found to have PV sleeves 2.94 mm longer than women (95% CI: 0.99-4.90 mm; P < 0.001). Sixty participants (30.5%) had one 4q25 risk allele and 6 (3.1%) had 2 alleles. There was no association between 4q25 genotype and PV sleeve length. Forty-six participants (23.4%) experienced arrhythmia recurrence within 3 to 12 months, but there was no association between recurrence and PV sleeve length. CONCLUSIONS: Common genetic variation at 4q25 was not associated with PV sleeve length and PV sleeve length was not associated with ablation outcomes. Men did have longer PV sleeves than women, but more research is needed to define the potential clinical significance of this observation.

Leadless versus transvenous single-chamber ventricular pacemakers: 3 year follow-up of the Micra CED study.

INTRODUCTION: The Micra Coverage with Evidence Development (CED) Study is a novel comparative analysis of Micra (leadless VVI) and transvenous single-chamber ventricular pacemakers (transvenous VVI) using administrative claims data. To compare chronic complications, device reinterventions, heart failure hospitalizations, and all-cause mortality after 3 years of follow-up. METHODS: US Medicare claims data linked to manufacturer device registration information were used to identify Medicare beneficiaries with a de novo implant of either a Micra VR leadless VVI or transvenous VVI pacemaker from March 9, 2017 to December 31, 2018. Unadjusted and propensity score overlap-weight adjusted Fine-Gray competing risk models were used to compare outcomes at 3 years. RESULTS: Leadless VVI patients (N = 6219) had a 32% lower rate of chronic complications and a 41% lower rate of reintervention compared with transvenous VVI patients (N = 10 212) (chronic complication hazard ratio [HR] 0.68; 95% confidence interval [CI], 0.59-0.78; reintervention HR 0.59; 95% CI 0.44-0.78). Infections rates were significantly lower among patients with a leadless VVI (<0.2% vs. 0.7%, p < .0001). Patients with a leadless VVI also had slightly lower rates of heart failure hospitalization (HR 0.90; 95% CI 0.84-0.97). There was no difference in the adjusted 3-year all-cause mortality rate (HR 0.97; 95% CI, 0.92-1.03). CONCLUSION: This nationwide comparative evaluation of leadless VVI versus transvenous VVI de novo pacemaker implants demonstrated that the leadless group had significantly fewer complications, reinterventions, heart failure hospitalizations, and infections than the transvenous group at 3 years, confirming that the previously reported shorter-term advantages associated with leadless pacing persist and continue to accrue in the medium-to-long-term.

Rationale for and use of the lumenless 3830 pacing lead.

Most currently available pacing and defibrillation leads utilize a stylet-based design that facilitates implantation. This has advantages, but also increases the lead diameter and adds the potential for metal fatigued-based conductor failure. A systematic literature search was conducted, and the authors add their twenty-year experience with this lead design. The global experience with lumenless leads was reviewed both for "standard" positioning and with conduction system pacing. Methods for both placement and system modification are reviewed. Lumenless leads have the potential to improve the durability of endocardial pacing and facilitate conduction system pacing.

Rationale and design of the Lead Evaluation for Defibrillation and Reliability study: Safety and efficacy of a novel ICD lead design.

BACKGROUND: Implantable cardioverter defibrillators (ICD) are indicated for primary and secondary prevention of sudden cardiac arrest. Despite enhancements in design and technologies, the ICD lead is the most vulnerable component of the ICD system and failure of ICD leads remains a significant clinical problem. A novel, small-diameter, lumenless, catheter-delivered, defibrillator lead was developed with the aim to improve long-term reliability. METHODS AND RESULTS: The Lead Evaluation for Defibrillation and Reliability (LEADR) study is a multi-center, single-arm, Bayesian, adaptive design, pre-market interventional pivotal clinical study. Up to 60 study sites from around the world will participate in the study. Patients indicated for a de novo ICD will undergo defibrillation testing at implantation and clinical assessments at baseline, implant, pre-hospital discharge, 3 months, 6 months, and every 6 months thereafter until official study closure. Patients may be participating for a minimum of 18 months to approximately 3 years. Fracture-free survival will be evaluated using a Bayesian statistical method that incorporates both virtual patient data (combination of bench testing to failure with in-vivo use condition data) with clinical patients. The clinical subject sample size will be determined using decision rules for number of subject enrollments and follow-up time based upon the observed number of fractures at certain time points in the study. The adaptive study design will therefore result in a minimum of 500 and a maximum of 900 patients enrolled. CONCLUSION: The LEADR Clinical Study was designed to efficiently provide evidence for short- and long-term safety and efficacy of a novel lead design using Bayesian methods including a novel virtual patient approach.

Randomized evaluation of decision support interventions for atrial fibrillation: Rationale and design of the RED-AF study.

BACKGROUND: Shared decision making (SDM) improves the likelihood that patients will receive care in a manner consistent with their priorities. To facilitate SDM, decision aids (DA) are commonly used, both to prepare a patient before their clinician visit, as well as to facilitate discussion during the visit. However, the relative efficacy of patient-focused or encounter-based DAs on SDM and patient outcomes remains largely unknown. We aim to directly estimate the comparative effectiveness of two DA's on SDM observed in encounters to discuss stroke prevention strategies in patients with atrial fibrillation (AF). METHODS: The study aims to recruit 1200 adult patients with non-valvular AF who qualify for anticoagulation therapy, and their clinicians who manage stroke prevention strategies, in a 2x2 cluster randomized multi-center trial at six sites. Two DA's were developed as interactive, online, non-linear tools: a patient decision aid (PDA) to be used by patients before the encounter, and an encounter decision aid (EDA) to be used by clinicians with their patients during the encounter. Patients will be randomized to PDA or usual care; clinicians will be randomized to EDA or usual care. RESULTS: Primary outcomes are quality of SDM, patient decision making, and patient knowledge. Secondary outcomes include anticoagulation choice, adherence, and clinical events. CONCLUSION: This trial is the first randomized, head-to-head comparison of the effects of an EDA versus a PDA on SDM. Our results will help to inform future SDM interventions to improve patients' AF outcomes and experiences with stroke prevention strategies.

Shared Decision Making in Cardiac Electrophysiology Procedures and Arrhythmia Management.

Shared decision making (SDM) has been advocated to improve patient care, patient decision acceptance, patient-provider communication, patient motivation, adherence, and patient reported outcomes. Documentation of SDM is endorsed in several society guidelines and is a condition of reimbursement for selected cardiovascular and cardiac arrhythmia procedures. However, many clinicians argue that SDM already occurs with clinical encounter discussions or the process of obtaining informed consent and note the additional imposed workload of using and documenting decision aids without validated tools or evidence that they improve clinical outcomes. In reality, SDM is a process and can be done without decision tools, although the process may be variable. Also, SDM advocates counter that the low-risk process of SDM need not be held to the high bar of demonstrating clinical benefit and that increasing the quality of decision making should be sufficient. Our review leverages a multidisciplinary group of experts in cardiology, cardiac electrophysiology, epidemiology, and SDM, as well as a patient advocate. Our goal is to examine and assess SDM methodology, tools, and available evidence on outcomes in patients with heart rhythm disorders to help determine the value of SDM, assess its possible impact on electrophysiological procedures and cardiac arrhythmia management, better inform regulatory requirements, and identify gaps in knowledge and future needs.

Clinical and radiographic predictors of cardiovascular implantable electronic device lead failure at the time of initial implantation.

OBJECTIVE: To assess the clinical and radiographic factors associated with lead failure by comparing subjects with lead failure within 10 years of implantation with an implant-year-matched group without lead failure. METHODS: A case-control study with 49 subjects who received Cardiac Implantable Electronic Device (CIED) between January 1, 1999 and July 31, 2008 and developed lead failure within 10 years of implantation in a single center. The control group consisted of subjects (n = 54) with normally functioning leads matched one-to-one by implant year. RESULTS: Among the failure group, the meantime from implantation to device lead failure was 4.70 ± 2.94 years. Older age at implantation was associated with a lower likelihood of lead failure (Odds Ratio (OR) = 0.28 (75 vs 42 years old), 95% CI 0.12-0.63, P = .002). A larger smallest loop diameter on the chest radiograph was also associated with a lower likelihood of lead failure (OR = 0.51 (31 vs 14 mm), 95% CI 0.27-0.97, P = .04). CIED type (defibrillator vs pacemaker) and Ottawa scores were not significantly associated with lead failure. Among lead-specific parameters, defibrillation lead vs pace-sense lead was associated with lead failure (OR = 3.91, 95% CI 1.95-7.81, P < .001). CONCLUSIONS: Younger age, defibrillation leads, and small lead loops are associated with lead failure in CIEDs. Techniques to avoid tight loops in the pocket could potentially reduce the risk of lead failure and bear important implications for the implanting physician.

Contemporaneous Comparison of Outcomes Among Patients Implanted With a Leadless vs Transvenous Single-Chamber Ventricular Pacemaker.

Importance: The safety and efficacy of leadless VVI pacemakers have been demonstrated in multiple clinical trials, but the comparative performance of the device in a large, real-world population has not been examined. Objective: To compare patient characteristics and complications among patients implanted with leadless VVI and transvenous VVI pacemakers. Design, Setting, Participants: The Longitudinal Coverage With Evidence Development Study on Micra Leadless Pacemakers (Micra CED) is a continuously enrolling observational cohort study evaluating complications, utilization, and outcomes of leadless VVI pacemakers in the US Medicare fee-for-service population. Patients implanted between March 9, 2017, and December 1, 2018, were identified and included. All Medicare patients implanted with leadless VVI and transvenous VVI pacemakers during the study period were enrolled. Patients with less than 12 months of continuous enrollment in Medicare prior to leadless VVI or transvenous VVI implant and with evidence of a prior cardiovascular implantable electronic device were excluded, leaving 5746 patients with leadless VVI pacemakers and 9662 patients with transvenous VVI pacemakers. Data were analyzed from May 2018 to April 2021. Exposures: Medicare patients implanted with leadless VVI pacemakers or transvenous VVI pacemakers. Main Outcomes and Measures: The main outcomes were acute (30-day) complications and 6-month complications. Results: Of 15 408 patients, 6701 (43.5%) were female, and the mean (SD) age was 81.0 (8.7) years. Compared with patients with transvenous VVI pacemakers, patients with leadless VVI pacemakers were more likely to have end-stage kidney disease (690 [12.0%] vs 226 [2.3%]; P < .001) and a higher mean (SD) Charlson Comorbidity Index score (5.1 [3.4] vs 4.6 [3.0]; P < .001). The unadjusted acute complication rate was higher in patients with leadless VVI pacemakers relative to transvenous VVI pacemakers (484 of 5746 [8.4%] vs 707 of 9662 [7.3%]; P = .02). However, there was no significant difference in overall acute complication rates following adjustment for patient characteristics (7.7% vs 7.4%; risk difference, 0.3; 95% CI, -0.6 to 1.3; P = .49). Pericardial effusion and/or perforation within 30 days was significantly higher among patients with leadless VVI pacemakers compared with patients with transvenous VVI pacemakers in both unadjusted and adjusted models (unadjusted, 47 of 5746 [0.8%] vs 38 of 9662 [0.4%]; P < .001; adjusted, 0.8% vs 0.4%; risk difference, 0.4; 95% CI, 0.1 to 0.7; P = .004). Patients implanted with leadless VVI pacemakers had a lower rate of 6-month complications compared with patients implanted with transvenous VVI pacemakers (unadjusted hazard ratio, 0.84; 95% CI, 0.68-1.03; P = .10; adjusted hazard ratio, 0.77; 95% CI, 0.62-0.96; P = .02). Conclusions and Relevance: In this study, despite significant differences in patient characteristics, patients in whom a leadless pacemaker was implanted were observed to have higher rates of pericardial effusion and/or perforation but lower rates of other device-related complications and requirements for device revision at 6 months. Understanding the benefits and risks associated with leadless VVI pacemakers compared with transvenous VVI pacemakers can help clinicians and patients make informed treatment decisions.

In vitro modeling accurately predicts cardiac lead fracture at 10 years.

BACKGROUND: Development of a cardiac lead fracture model has the potential to differentiate well-performing lead designs from poor performing ones and could aid in future lead development. OBJECTIVE: The purpose of this study was to demonstrate a predictive model for lead fracture and validate the results generated by the model by comparing them to observed 10-year implantable cardioverter-defibrillator lead fracture-free survival. METHODS: The model presented here uses a combination of in vivo patient data, in vitro conductor fatigue test data, and statistical simulation to predict the fracture-free survival of cardiac leads. The model was validated by comparing the results to human clinical performance data from the Medtronic Sprint Fidelis (Minneapolis, MN) models 6931 (single coil, active fixation) and 6949 (dual coil, active fixation), as well as the Quattro model 6947 (dual coil, active fixation). RESULTS: Median patient age in the single coil Fidelis 6931 population (64 years) was less than in the dual coil Fidelis 6949 and Quattro populations (68 years). Modeled and observed fracture-free survival for Quattro (>97%) was superior to that for Fidelis (<94%). The modeled survival agreed with the observed fracture-free survival data. The average model error was 0.3% (SD 1.2%). CONCLUSION: This model for cardiac lead fracture-free survival using in vivo lead bending measurements and in vitro bench testing can be used to predict lead performance as observed by alignment with field survival data.

Risk Factors for Repeat Infection and Mortality After Extraction of Infected Cardiovascular Implantable Electronic Devices.

OBJECTIVES: This study sought to investigate the factors associated with repeat infection following lead extraction procedures. BACKGROUND: Although lead extraction is an essential therapy for patients with cardiovascular implantable electronic device (CIED) infection, repeat infection still occurs in some patients. METHODS: The authors reviewed data for consecutive patients who underwent extraction of infected CIEDs from August 2003 to May 2019. Repeat infection was defined as infective endocarditis, sepsis with no alternative focus, or pocket infection after extraction of infected CIEDs. RESULTS: Extraction of infected CIEDs was performed in 496 patients. The most commonly implicated pathogen was Staphylococcus aureus (n = 188). In 449 patients (90.5%), all leads were completely extracted using only transvenous techniques. Thirty-three patients (6.7%) underwent surgical lead extraction, and 14 (2.8%) had retained leads or lead components. After a median follow-up of 352 [40 to 1,255] days after CIED extraction, 144 patients (29.0%) died. Repeat infection occurred in 47 patients (9.5%) with the median time from the extraction to repeat infection of 103 [45 to 214] days. In multivariable analysis, presence of a left ventricular assist device, younger age at extraction, and S. aureus infection were independent predictors of repeat infection. Additionally, chronic kidney disease, congestive heart failure, presence of septic emboli, S. aureus infection, and occurrence of major complications were independent predictors of increased mortality. CONCLUSIONS: Patients with S. aureus infection have a high risk of repeat infection and poor prognosis after CIED extraction. Repeat infection is also predicted by younger age and the presence of a left ventricular assist device, whereas mortality was predicted by congestive heart failure, chronic kidney disease, and septic emboli.