Thermophotovoltaic efficiency of 40.

Thermophotovoltaics (TPVs) convert predominantly infrared wavelength light to electricity via the photovoltaic effect, and can enable approaches to energy storage1,2 and conversion3-9 that use higher temperature heat sources than the turbines that are ubiquitous in electricity production today. Since the first demonstration of 29% efficient TPVs (Fig. 1a) using an integrated back surface reflector and a tungsten emitter at 2,000 °C (ref. 10), TPV fabrication and performance have improved11,12. However, despite predictions that TPV efficiencies can exceed 50% (refs. 11,13,14), the demonstrated efficiencies are still only as high as 32%, albeit at much lower temperatures below 1,300 °C (refs. 13-15). Here we report the fabrication and measurement of TPV cells with efficiencies of more than 40% and experimentally demonstrate the efficiency of high-bandgap tandem TPV cells. The TPV cells are two-junction devices comprising III-V materials with bandgaps between 1.0 and 1.4 eV that are optimized for emitter temperatures of 1,900-2,400 °C. The cells exploit the concept of band-edge spectral filtering to obtain high efficiency, using highly reflective back surface reflectors to reject unusable sub-bandgap radiation back to the emitter. A 1.4/1.2 eV device reached a maximum efficiency of (41.1 ± 1)% operating at a power density of 2.39 W cm-2 and an emitter temperature of 2,400 °C. A 1.2/1.0 eV device reached a maximum efficiency of (39.3 ± 1)% operating at a power density of 1.8 W cm-2 and an emitter temperature of 2,127 °C. These cells can be integrated into a TPV system for thermal energy grid storage to enable dispatchable renewable energy. This creates a pathway for thermal energy grid storage to reach sufficiently high efficiency and sufficiently low cost to enable decarbonization of the electricity grid.

Severe mental illness: cardiovascular risk assessment and management.

Patients with severe mental illness (SMI) including schizophrenia and bipolar disorder die on average 15-20 years earlier than the general population often due to sudden death that, in most cases, is caused by cardiovascular disease. This state-of-the-art review aims to address the complex association between SMI and cardiovascular risk, explore disparities in cardiovascular care pathways, describe how to adequately predict cardiovascular outcomes, and propose targeted interventions to improve cardiovascular health in patients with SMI. These patients have an adverse cardiovascular risk factor profile due to an interplay between biological factors such as chronic inflammation, patient factors such as excessive smoking, and healthcare system factors such as stigma and discrimination. Several disparities in cardiovascular care pathways have been demonstrated in patients with SMI, resulting in a 47% lower likelihood of undergoing invasive coronary procedures and substantially lower rates of prescribed standard secondary prevention medications compared with the general population. Although early cardiovascular risk prediction is important, conventional risk prediction models do not accurately predict long-term cardiovascular outcomes as cardiovascular disease and mortality are only partly driven by traditional risk factors in this patient group. As such, SMI-specific risk prediction models and clinical tools such as the electrocardiogram and echocardiogram are necessary when assessing and managing cardiovascular risk associated with SMI. In conclusion, there is a necessity for differentiated cardiovascular care in patients with SMI. By addressing factors involved in the excess cardiovascular risk, reconsidering risk stratification approaches, and implementing multidisciplinary care models, clinicians can take steps towards improving cardiovascular health and long-term outcomes in patients with SMI.

Cardiac Resynchronization Therapy Improves Outcomes in Patients With Intraventricular Conduction Delay But Not Right Bundle Branch Block: A Patient-Level Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Benefit from cardiac resynchronization therapy (CRT) varies by QRS characteristics; individual randomized trials are underpowered to assess benefit for relatively small subgroups. METHODS: The authors analyzed patient-level data from pivotal CRT trials (MIRACLE [Multicenter InSync Randomized Clinical Evaluation], MIRACLE-ICD [Multicenter InSync ICD Randomized Clinical Evaluation], MIRACLE-ICD II [Multicenter InSync ICD Randomized Clinical Evaluation II], REVERSE [Resynchronization Reverses Remodeling in Systolic Left Ventricular Dysfunction], RAFT [Resynchronization-Defibrillation for Ambulatory Heart Failure], BLOCK-HF [Biventricular Versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block], COMPANION [Comparison of Medical Therapy, Pacing and Defibrillation in Heart Failure], and MADIT-CRT [Multicenter Automatic Defibrillator Implantation Trial - Cardiac Resynchronization Therapy]) using Bayesian Hierarchical Weibull survival regression models to assess CRT benefit by QRS morphology (left bundle branch block [LBBB], n=4549; right bundle branch block [RBBB], n=691; and intraventricular conduction delay [IVCD], n=1024) and duration (with 150-ms partition). The continuous relationship between QRS duration and CRT benefit was also examined within subgroups defined by QRS morphology. The primary end point was time to heart failure hospitalization (HFH) or death; a secondary end point was time to all-cause death. RESULTS: Of 6264 patients included, 25% were women, the median age was 66 [interquartile range, 58 to 73] years, and 61% received CRT (with or without an implantable cardioverter defibrillator). CRT was associated with an overall lower risk of HFH or death (hazard ratio [HR], 0.73 [credible interval (CrI), 0.65 to 0.84]), and in subgroups of patients with QRS ≥150 ms and either LBBB (HR, 0.56 [CrI, 0.48 to 0.66]) or IVCD (HR, 0.59 [CrI, 0.39 to 0.89]), but not RBBB (HR 0.97 [CrI, 0.68 to 1.34]; Pinteraction <0.001). No significant association for CRT with HFH or death was observed when QRS was <150 ms (regardless of QRS morphology) or in the presence of RBBB. Similar relationships were observed for all-cause death. CONCLUSIONS: CRT is associated with reduced HFH or death in patients with QRS ≥150 ms and LBBB or IVCD, but not for those with RBBB. Aggregating RBBB and IVCD into a single "non-LBBB" category when selecting patients for CRT should be reconsidered. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifiers: NCT00271154, NCT00251251, NCT00267098, and NCT00180271.

Benefit of cardiac resynchronization therapy among older patients: A patient-level meta-analysis.

BACKGROUND: Cardiac resynchronization therapy (CRT) reduces heart failure hospitalizations (HFH) and mortality for guideline-indicated patients with heart failure (HF). Most patients with HF are aged ≥70 years but such patients are often under-represented in randomized trials. METHODS: Patient-level data were combined from 8 randomized trials published 2002-2013 comparing CRT to no CRT (n = 6,369). The effect of CRT was estimated using an adjusted Bayesian survival model. Using age as a categorical (<70 vs ≥70 years) or continuous variable, the interaction between age and CRT on the composite end point of HFH or all-cause mortality or all-cause mortality alone was assessed. RESULTS: The median age was 67 years with 2436 (38%) being 70+; 1,554 (24%) were women; 2,586 (41%) had nonischemic cardiomyopathy and median QRS duration was 160 ms. Overall, CRT was associated with a delay in time to the composite end point (adjusted hazard ratio [aHR] 0.75, 95% credible interval [CI] 0.66-0.85, P = .002) and all-cause mortality alone (aHR of 0.80, 95% CI 0.69-0.96, P = .017). When age was treated as a categorical variable, there was no interaction between age and the effect of CRT for either end point (P > .1). When age was treated as a continuous variable, older patients appeared to obtain greater benefit with CRT for the composite end point (P for interaction = .027) with a similar but nonsignificant trend for mortality (P for interaction = .35). CONCLUSION: Reductions in HFH and mortality with CRT are as great or greater in appropriately indicated older patients. Age should not be a limiting factor for the provision of CRT.

Peak frequency mapping of atypical atrial flutter.

INTRODUCTION: Peak frequency (PF) mapping is a novel method that may identify critical portions of myocardial substrate supporting reentry. The aim of this study was to describe and evaluate PF mapping combined with omnipolar voltage mapping in the identification of critical isthmuses of left atrial (LA) atypical flutters. METHODS AND RESULTS: LA omnipolar voltage and PF maps were generated in flutter using the Advisor HD-Grid catheter (Abbott) and EnSite Precision Mapping System (Abbott) in 12 patients. Normal voltage was defined as ≥0.5 mV, low-voltage as 0.1-0.5 mV, and scar as <0.1 mV. PF distributions were compared with ANOVA and post hoc Tukey analyses. The 1 cm radius from arrhythmia termination was compared to global myocardium with unpaired t-testing. The mean age was 65.8 ± 9.7 years and 50% of patients were female. Overall, 34 312 points were analyzed. Atypical flutters most frequently involved the mitral isthmus (58%) or anterior wall (25%). Mean PF varied significantly by myocardial voltage: normal (335.5 ± 115.0 Hz), low (274.6 ± 144.0 Hz), and scar (71.6 ± 140.5 Hz) (p < .0001 for all pairwise comparisons). All termination sites resided in low-voltage regions containing intermediate or high PF. Overall, mean voltage in the 1 cm radius from termination was significantly lower than the remaining myocardium (0.58 vs. 0.95 mV, p < .0001) and PF was significantly higher (326.4 vs. 245.1 Hz, p < .0001). CONCLUSION: Low-voltage, high-PF areas may be critical targets during catheter ablation of atypical atrial flutter.

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.

Rates and predictors of hospital and emergency department care after catheter ablation of atrial fibrillation.

INTRODUCTION: Although atrial fibrillation (AF) ablation has become increasingly safer, rehospitalization and emergency department (ED) evaluations can occur in the postablation period. Better understanding of the frequency, causes, and predictors for hospitalization and ED evaluation after ablation are needed, particularly as same-day discharge programs expand. METHODS: The Optum Clinformatics database was used to define rates, causes, and predictors of hospital and ED care after AF ablation performed between January 2016 and May 2019. Primary outcomes were all-cause hospital and ED care within 30 days of discharge. Independent predictors of all-cause ED and hospital admissions care were determined via logistic regression. RESULTS: Of the 18 848 patients in this study, the mean age was 67.5 ± 10 years, 37.9% were female, and the mean CHA2 DS2 -VASc score was 3.27 ± 1.84. Within 30 days of AF ablation, 1440 of 18 848 patients (7.6%) required hospital care of which 15% had >1 admission; 7.9% required ED care of which 28.6% had >1 ED visit. The most common reasons for hospital admission (which occurred on average 12.3 days after discharge) were supraventricular tachycardia (SVT) or AF (33.2%), heart failure (12.7%), and infection (12.2%). The most common reasons for ED care were SVT/AF (15.0%), noncardiac chest pain (13.3%), and noninfectious respiratory illness (12.2%). Age, female sex, ablation in an inpatient setting, and co-morbidities were associated with increased risk of rehospitalization. Age, female sex, patient comorbidities, and non-use of direct oral anticoagulation were associated with increased risk of ED visit. CONCLUSION: Approximately 7%-8% of patients require unplanned hospitalization or ED care after AF ablation, most commonly due to SVT/AF. Predictors of unscheduled care include patient age, sex, and several patient comorbidities. This study can inform quality improvement initiatives by identifying common causes for unscheduled care.

Watchman device migration and embolization: A report from the NCDR LAAO Registry.

INTRODUCTION: Incomplete anchoring of the Watchman left atrial appendage closure (LAAO) device can result in substantial device migration or device embolization (DME) requiring percutaneous or surgical retrieval. METHODS: We performed a retrospective analysis of Watchman procedures (January 2016 through March 2021) reported to the National Cardiovascular Data Registry LAAO Registry. We excluded patients with prior LAAO interventions, no device released, and missing device information. In-hospital events were assessed among all patients and postdischarge events were assessed among patients with 45-day follow-up. RESULTS: Of 120 278 Watchman procedures, the in-hospital DME rate was 0.07% (n = 84) and surgery was commonly performed (n = 39). In-hospital mortality rate was 14% among patients with DME and 20.5% among patients who underwent surgery. In-hospital DME was more common: at hospitals with a lower median annual procedure volume (24 vs. 41 procedures, p < .0001), with Watchman 2.5 versus Watchman FLX devices (0.08% vs. 0.04%, p = .0048), with larger LAA ostia (median 23 vs. 21 mm, p = .004), and with a smaller difference between device and LAA ostial size (median difference 4 vs. 5 mm, p = .04). Of 98 147 patients with 45-day follow-up, postdischarge DME occurred in 0.06% (n = 54) patients and cardiac surgery was performed in 7.4% (n = 4) of cases. The 45-day mortality rate was 3.7% (n = 2) among patients with postdischarge DME. Postdischarge DME was more common among men (79.7% of events but 58.9% of all procedures, p = .0019), taller patients (177.9 vs. 172 cm, p = .0005), and those with greater body mass (99.9 vs. 85.5 kg, p = .0055). The rhythm at implant was less frequently AF among patients with DME compared to those without (38.9% vs. 46.9%, p = .0098). CONCLUSION: While Watchman DME is rare, it is associated with high mortality and frequently requires surgical retrieval, and a substantial proportion of events occur after discharge. Due to the severity of DME events, risk mitigation strategies and on-site cardiac surgical back-up are of paramount importance.

Voltage gradients in transvenous and subcutaneous defibrillation and their risk of myocardial damage.

INTRODUCTION: Transvenous implantable cardioverter-defibrillator (ICD) shocks have been associated with cardiac biomarker elevations and are thought in some cases to contribute to adverse clinical outcomes and mortality, possibly from myocardium exposed to excessive shock voltage gradients. Currently, there are only limited data for comparison with subcutaneous ICDs. We sought to compare ventricular myocardium voltage gradients resulting from transvenous (TV) and subcutaneous defibrillator (S-ICD) shocks to assess their risk of myocardial damage. METHODS: A finite element model was derived from thoracic magnetic resonance imaging (MRI). Voltage gradients were modeled for an S-ICD with a left-sided parasternal coil and a left-sided TV-ICD with a mid-cavity, a septal right ventricle (RV) coil, or a dual coil lead (TV mid, TV septal, TV septal + superior vena cava [SVC]). High gradients were defined as > 100 V/cm. RESULTS: The volumes of ventricular myocardium with high gradients > 100 V/cm were 0.02, 2.4, 7.7, and 0 cc for TV mid, TV septal, TV septal + SVC, and S-ICD, respectively. CONCLUSION: Our models suggest that S-ICD shocks produce more uniform gradients in the myocardium, with less exposure to potentially damaging electrical fields, compared to TV-ICDs. Dual coil TV leads yield higher gradients, as does closer proximity of the shock coil to the myocardium.

Cardiac resynchronization therapy in patients with a prior history of atrial fibrillation: Insights from four major clinical trials.

AIMS: To investigate the association of cardiac resynchronization therapy (CRT) on outcomes among participants with and without a history of atrial fibrillation (AF). METHODS: Individual-patient-data from four randomized trials investigating CRT-Defibrillators (COMPANION, MADIT-CRT, REVERSE) or CRT-Pacemakers (COMPANION, MIRACLE) were analyzed. Outcomes were time to a composite of heart failure hospitalization or all-cause mortality or to all-cause mortality alone. The association of CRT on outcomes for patients with and without a history of AF was assessed using a Bayesian-Weibull survival regression model adjusting for baseline characteristics. RESULTS: Of 3964 patients included, 586 (14.8%) had a history of AF; 2245 (66%) were randomized to CRT. Overall, CRT reduced the risk of the primary composite endpoint (hazard ratio [HR]: 0.69, 95% credible interval [CI]: 0.56-0.81). The effect was similar (posterior probability of no interaction = 0.26) in patients with (HR: 0.78, 95% CI: 0.55-1.10) and without a history of AF (HR: 0.67, 95% CI: 0.55-0.80). In these four trials, CRT did not reduce mortality overall (HR: 0.82, 95% CI: 0.66-1.01) without evidence of interaction (posterior probability of no interaction = 0.14) for patients with (HR: 1.09, 95% CI: 0.70-1.74) or without a history of AF (HR: 0.70, 95% CI: 0.60-0.97). CONCLUSION: The association of CRT on the composite endpoint or mortality was not statistically different for patients with or without a history of AF, but this could reflect inadequate power. Our results call for trials to confirm the benefit of CRT recipients with a history of AF.

Development and validation of an automated algorithm for end point adjudication for a large U.S. national registry.

BACKGROUND: Clinical events committee (CEC) evaluation is the standard approach for end point adjudication in clinical trials. Due to resource constraints, large registries typically rely on site-reported end points without further confirmation, which may preclude use for regulatory oversight. METHODS: We developed a novel automated adjudication algorithm (AAA) for end point adjudication in the National Cardiovascular Data Registry Left Atrial Appendage Occlusion (LAAO) Registry using an iterative process using CEC adjudication as the "gold standard." A ≥80% agreement rate between automated algorithm adjudication and CEC adjudication was prespecified as clinically acceptable. Agreement rates were calculated. RESULTS: A total of 92 in-hospital and 127 post-discharge end points were evaluated between January 1, 2016 and June 30, 2019 using AAA and CEC. Agreement for neurologic events was >90%. Percent agreement for in-hospital and post-discharge events was as follows: ischemic stroke 95.7% and 94.5%, hemorrhagic stroke 97.8% and 96.1%, undetermined stroke 97.8% and 99.2%, transient ischemic attack 98.9% and 98.4% and intracranial hemorrhage 100.0% and 94.5%. Agreement was >80% for major bleeding (83.7% and 90.6%) and major vascular complication (89.1% and 97.6%). With this approach, <1% of site reported end points require CEC adjudication. Agreement remained very good during the period after algorithm derivation. CONCLUSIONS: An AAA-guided approach for end point adjudication was successfully developed and validated for the LAAO Registry. With this approach, the need for formal CEC adjudication was substantially reduced, with accuracy maintained above an 80% agreement threshold. After application specific validation, these methods could be applied to large registries and clinical trials to reduce the cost of event adjudication while preserving scientific validity.

Subcutaneous and Transvenous ICDs: an Update on Contemporary Questions and Controversies.

PURPOSE OF REVIEW: While the subcutaneous (S-) implantable cardioverter-defibrillator (ICDs) is an alternative to the transvenous (TV-) ICD in many patients, optimal use remains unclear. In this review, we summarize recent clinically relevant data on sensing algorithms, inappropriate shocks, defibrillation testing, and battery and electrode failures. RECENT FINDINGS: Changes in sensing algorithms and S-ICD programming have significantly decreased inappropriate shock rates. Avoiding fat below the S-ICD coil and can is key for reducing the defibrillation threshold. While S-ICD battery and electrode failures have resulted in recalls, system components remain commercially available since failure rates are low and no other similar devices are available. The S-ICD is a good alternative to the TV-ICD for many patients, and particularly in light of recently developed device algorithms and improvements in implant technique. Future research will need to better understand: the impact of S-ICD electrode and battery failures and the potential for integrating leadless pacing into a modular S-ICD platform.

Left bundle-branch block is associated with asimilar dyssynchronous phenotype in heart failure patients with normal and reduced ejection fractions.

BACKGROUND: Few therapies improve outcomes in patients with heart failure with preserved ejection fraction (HFpEF). If left bundle-branch block (LBBB) is associated with left ventricular dyssynchrony and impaired cardiac performance in HFpEF, cardiac resynchronization therapy could be a promising treatment. METHODS: We performed a cross-sectional analysis of selected patients with HFpEF (ejection fraction ≥50%) with and without LBBB (normal conduction, NC) and patients with HFrEF and LBBB who were suitable cardiac resynchronization therapy candidates to describe and contextualize the mechanical phenotype of LBBB in HFpEF. Systolic and diastolic isovolumic times, ejection time(ET), and diastolic filling time(DFT) were measured on spectral tissue Doppler echocardiographic images and indexed to the heart rate. Dyssynchrony pattern was assessed using speckle-tracked longitudinal strain patterns. Comparisons were performed using analysis of variance and χ2 test with posthoc pairwise comparisons as indicated. RESULTS: Eighty-two HFpEF (50 with NC, 32 with LBBB) and 149 HFrEF (all with LBBB) patients met criteria. Overall, 84.4% with HFpEF/LBBB and 91.3% with HFrEF/LBBB had demonstrable mechanical dyssynchrony compared to 0% with HFpEF/NC. Compared to HFpEF/NC, HFpEF/LBBB had significantly prolonged isovolumetric contraction time (ICT), isovolumetric relaxation time (IRT), and total isovolumetric time and significantly shorter ET (all indexed). LBBB/HFrEF patients, compared to LBBB/HFpEF patients, had increased ICT and IRT with decreased DFT but similar ET. CONCLUSIONS: Patients with HFpEF and LBBB frequently have an LBBB dyssynchrony phenotype, prolonged ICT and IRT, and reduced ET compared to HFpEF patients with NC. The electromechanical dyssynchrony and disordered cardiac timing of HFpEF with LBBB are similar to HFrEF with LBBB.

The role of posterior wall isolation in catheter ablation of persistent atrial fibrillation.

The left atrial posterior wall has many embryologic, anatomic, and electrophysiologic characteristics, that are important for the initiation and maintenance of persistent atrial fibrillation. The left atrial posterior wall is a potential target for ablation in patients with persistent atrial fibrillation, a population in whom pulmonary vein isolation alone has resulted in unsatisfactory recurrence rates. Published clinical studies report conflicting results on the safety and efficacy of posterior wall isolation. Emerging technologies including optimized use of radiofrequency ablation, pulse field ablation, and combined endocardial/epicardial ablation may optimize approaches to posterior wall isolation and reduce the risk of injury to nearby structures such as the esophagus. Critical evaluation of future and ongoing clinical studies of posterior wall isolation requires careful scrutiny of many characteristics, including intraprocedural definition of posterior wall isolation, concomitant extrapulmonary vein ablation, and study endpoints.

Procedure characteristics and outcomes of atrial fibrillation ablation procedures using cryoballoon versus radiofrequency ablation: A report from the GWTG-AFIB registry.

INTRODUCTION: Cryoballoon ablation (CBA) is an alternative to radiofrequency ablation (RFA) for ablation of atrial fibrillation (AF) and real-world comparisons of this strategy are lacking. As such, we sought to compare patient and periprocedural characteristics and outcomes of CBA versus RFA in the Get With the Guidelines AFIB Registry. METHODS: Categorical variables were compared via the χ2 test and continuous variables were compared via the Wilcoxon rank-sum test. Adjusted analyses were performed using overlap weighting of propensity scores. RESULTS: A total of 5247 (1465 CBA, 3782 RFA) ablation procedures were reported from 33 sites. Those undergoing CBA more often had paroxysmal AF (60.0% vs. 48.8%) and no prior AF ablation (87.5% vs. 73.8%). CHA2 DS2 -VASc scores were similar. Among de novo ablations, most ablations involved intracardiac echocardiography and electroanatomic mapping, but both were less common with CBA (87.3% vs. 93.9%, p < .0001, and 87.7% vs. 94.6%, p < .0001, respectively). CBA was associated with shorter procedures (129 vs. 179 min, p < .0001), increased fluoroscopy use (19 vs. 11 min, p < .0001), and similar ablation times (27 vs. 35 min, p = .15). Nonpulmonary vein ablation was common with CBA: roof line 38.6%, floor line 20.4%, cavotricuspid isthmus 27.7%. RFA was associated with more total complications compared to CBA (5.4% vs. 2.3%, p < .0001), due to more volume overload and "other" events, although phrenic nerve injury was more common with CBA (0.9% vs 0.1%, p = .0001). In the adjusted model, any complication was less common among CBA cases (odds ratio, 0.45; confidence interval, 0.25-0.79, p = .0056). CONCLUSION: CBA was associated with fewer complications, and shorter procedure times, and greater fluoroscopy times, compared to RFA. Nonpulmonary vein ablation and electroanatomic mapping system use was common with CBA.

Cannabis use disorder among atrial fibrillation admissions, 2008-2018.

BACKGROUND: Despite changes inthe legality of cannabis use and the increasing prevalence of cannabis use disorder (CUD), there is little data investigating the association between CUD and inpatient atrial fibrillation (AF) hospitalizations. METHODS: Using the National Inpatient Sample, we identified Atrial Fibrillation (AF) hospitalizations with and without a codiagnosis of CUD using International Classification of Diseases diagnosis codes and compared demographics, socioeconomics, comorbidities, outcomes, and trends between cohorts. RESULTS: Between 2008 and 2018, we identified 5,155,789 admissions for AF of which 31,768 (0.6%) had a codiagnosis of CUD. The proportion of admissions with a history of CUD increased from 0.3% in 2008 to 1.0% in 2018 (p < .001). Hospital discharges of patients with CUD were significantly younger (53 vs. 72 years, p < .001), had a higher proportion of black race (CUD: 26.6% vs. 8.0%, p < .001), and had a higher proportion of income in the lowest income quartile than without a codiagnosis of CUD (CUD: 40.5% vs. 26.2%, p < .001). CONCLUSIONS: CUD is increasingly prevalent among AF hospitalizations, particularly among young patients. Codiagnosis of CUD in AF hospitalizations is also more common in underserved patients. As a result, it is important for future research to examine and understand the impact of CUD on this population, particularly in the light of changing legislation surrounding the legality of cannabis.

Association between vectorcardiographic QRS area and incident heart failure diagnosis and mortality among patients with left bundle branch block: A register-based cohort study.

BACKGROUND: QRS duration and morphology including left bundle branch block (LBBB) are the most widely used electrocardiogram (ECG) markers for assessing ventricular dyssynchrony and predicting heart failure (HF). However, the vectorcardiographic QRS area may more accurately identify delayed left ventricular activation and HF development. OBJECTIVE: We investigated the association between QRS area and incident HF risk in patients with LBBB. METHODS: By crosslinking data from Danish nationwide registries, we identified patients with a first-time digital LBBB ECG between 2001 and 2015. The vectorcardiographic QRS area was derived from a 12­lead ECG using the Kors transformation method and grouped into quartiles. The endpoint was a composite of HF diagnosis, filled prescriptions for loop diuretics, or death from HF. Cause-specific multivariable Cox regression was used to compute hazard ratios(HR) with 95% confidence intervals(CI). RESULTS: We included 3316 patients with LBBB free from prior HF-related events (median age, 72 years; male, 40%). QRS area quartiles comprised Q1, 36-98 µVs; Q2, 99-119 µVs; Q3, 120-145 µVs; and Q4, 146-295 µVs. During a 5-year follow-up, 31% of patients reached the composite endpoint, with a rate of 39% in the highest quartile Q4. A QRS area in quartile Q4 was associated with increased hazard of the composite endpoint (HR:1.48, 95%CI:1.22-1.80) compared with Q1. CONCLUSIONS: Among primary care patients with newly discovered LBBB, a large vectorcardiographic QRS area (146-295 µVs) was associated with an increased risk of incident HF diagnosis, filling prescriptions for loop diuretics, or dying from HF within 5-years.

Healthcare utilization and cost in patients with atrial fibrillation and heart failure undergoing catheter ablation.

BACKGROUND: Catheter ablation is an effective treatment for patients with atrial fibrillation (AF) and heart failure (HF). However, little is known about how healthcare utilization and cost change after ablation in this population. We sought to determine healthcare utilization and cost patterns among patients with AF and HF undergoing ablation. METHODS: Using a large United States administrative database, we identified (n = 1568) treated with ablation with a primary and secondary diagnosis of AF and HF, respectively, were evaluated 1-year pre- and postablation for outcomes including inpatient admissions (AF or HF), emergency department (ED) visits, cardioversions, length of stay (LOS), and cost. A secondary analysis was extended to 3-years postablation. RESULTS: Reductions were observed in AF-related admissions (64%), LOS (65%), cardioversions (52%), ED visits (51%, all values, p < .0001), and HF-related admissions (22%, p = .01). There was a 40% reduction in inpatient admission cost ($4165 preablation to $2510 postablation, p < .0001). In a sensitivity analysis excluding repeat-ablation patients, a greater reduction in overall AF management cost was observed compared to the full cohort (-43% vs. -2%). Comparing 1-year pre- to 3-years postablation, both total mean AF-management cost ($850 per-patient per-month 1-year pre- to $546 3-years postablation, p < .0001) and AF-related healthcare utilization was reduced. CONCLUSIONS: Catheter ablation in patients with AF and HF resulted in significant reductions in healthcare utilization and cost through 3-years of follow-up. This reduction was observed regardless of whether repeat ablation was performed, reflecting the positive impact of ablation on longer term cost reduction.

Implantable cardioverter-defibrillator lead revision following left ventricular assist device implantation.

INTRODUCTION: Lead dysfunction can lead to serious consequences including failure to treat ventricular tachycardia or fibrillation (VT/VF). The incidence and mechanisms of lead dysfunction following left ventricular assist device (LVAD) implantation are not well-described. We sought to determine the incidence, mechanisms, timing, and complications of right ventricular lead dysfunction requiring revision following LVAD implantation. METHODS: Retrospective observational chart review of all LVAD recipients with pre-existing implantable cardioverter-defibrillator (ICD) from 2009 to 2018 was performed including device interrogation reports, laboratory and imaging data, procedural reports, and clinical outcomes. RESULTS: Among 583 patients with an ICD in situ undergoing LVAD implant, the median (interquartile range) age was 62.5 (15.7) years, 21% were female, and the types of LVADs included HeartWare HVAD (26%), HeartMate II (52%), and HeartMate III (22%). Right ventricular lead revision was performed in 38 patients (6.5%) at a median (25th, 75th) of 16.4 (3.6, 29.2) months following LVAD. Mechanisms of lead dysfunction included macrodislodgement (n = 4), surgical lead injury (n = 4), recall (n = 3), insulation failure (n = 8) or conductor fracture (n = 7), and alterations in the lead-myocardial interface (n = 12). Undersensing requiring revision occurred in 22 (58%) cases. Clinical sequelae of undersensing included failure to detect VT/VF (n = 4) and pacing-induced torsade de pointes (n = 1). Oversensing occurred in 12 (32%) and sequelae included inappropriate antitachycardia pacing ([ATP], n = 8), inappropriate ICD shock (n = 6), and ATP-induced VT (n = 1). CONCLUSION: The incidence of right ventricular lead dysfunction following LVAD implantation is significant and has important clinical sequelae. Physicians should remain vigilant for lead dysfunction after LVAD surgery and test lead function before discharge.

Lead one ratio in left bundle branch block predicts poor cardiac resynchronization therapy response.

BACKGROUND: A low electrocardiogram (ECG) lead one ratio (LOR) of the maximum positive/negative QRS amplitudes is associated with lower left ventricular ejection fraction (LVEF) and worse outcomes in left bundle branch block (LBBB); however, the impact of LOR on cardiac resynchronization therapy (CRT) outcomes is unknown. We compared clinical outcomes and echocardiographic changes after CRT implantation by LOR. METHODS: Consecutive CRT-defibrillator recipients with LBBB implanted between 2006 and 2015 at Duke University Medical Center were included (N = 496). Time to heart transplant, left ventricular assist device (LVAD) implantation, or death was compared among patients with LOR <12 vs ≥12 using Cox-proportional hazard models. Changes in LVEF and LV volumes after CRT were compared by LOR. RESULTS: Baseline ECG LOR <12 was associated with an adjusted hazard ratio (HR) of 1.69 (95% CI: 1.12-2.40, P = .01) for heart transplant, LVAD, or death. Patients with LOR <12 had less reduction of LV end diastolic volume (ΔLVEDV -4 ± 21 vs -13 ± 23%, P = .04) and LV end systolic volume (ΔLVESV -9 ± 27 vs -22 ± 26%, P = .03) after CRT. In patients with QRS duration (QRSd) ≥150 ms, LOR <12 was associated with an adjusted HR of 2.01 (95% CI 1.21-3.35, P = .008) for heart transplant, LVAD, or death, compared with LOR ≥12. CONCLUSIONS: Baseline ECG LOR <12 portends worse outcomes after CRT implantation in patients with LBBB, specifically among those with QRSd ≥150 ms. This ECG ratio may identify patients with a class I indication for CRT implantation at high risk for poor postimplantation outcomes.