Prognosis of patients in end-stage heart failure with atrial fibrillation treated with ablation: Insights from CASTLE-HTx.

BACKGROUND: The CASTLE-HTx trial demonstrated the benefit of atrial fibrillation (AF) ablation compared with medical therapy in decreasing mortality, need for left ventricular assist device implantation, or heart transplantation (HTx) in patients with end-stage heart failure (HF). OBJECTIVE: This analysis aimed to identify risk factors related to adverse outcomes in patients with end-stage HF and to assess the impact of ablation. METHODS: The CASTLE-HTx protocol randomized 194 patients with end-stage HF and AF to ablation vs medical therapy. We identified left ventricular ejection fraction <30%, New York Heart Association class ≥III, and AF burden >50% as predictors for the primary end point. The CASTLE-HTx risk score assigned weights to these risk factors. Patients with a risk score ≥3 were identified as high risk. RESULTS: The patients were assigned to low-risk (89 [45.9%]) and high-risk (105 [54.1%]) groups. After a median follow-up of 18 months, a primary end point event occurred in 6 and 31 patients of the low- and high-risk groups (hazard ratio, 4.98; 95% confidence interval, 2.08-11.9). The incidence rate (IR) difference between ablation and medical therapy was much larger in high-risk patients (8/49 [IR, 11.4] vs 23/56 [IR, 36.1]) compared with low-risk patients (2/48 [IR, 2.6] vs 4/41 [IR, 6.3]). The IR difference for ablation was significantly higher in high-risk patients (24.69) compared with low-risk patients (3.70). CONCLUSION: The absolute benefit of ablation is more pronounced in high-risk patients, but low-risk patients may also benefit. The CASTLE-HTx risk score identifies patients with end-stage HF who will particularly benefit from ablation.

Left atrial volume affects the correlation of voltage map with magnetic resonance imaging.

BACKGROUND: The low-voltage area detected by electroanatomic mapping (EAM) is a surrogate marker of left atrial fibrosis. However, the correlation between the EAM and late gadolinium enhancement magnetic resonance imaging (LGE-MRI) has been inconsistent among studies. This study aimed to investigate how LA size affects the correlation between EAM and LGE-MRI. METHODS: High-density EAMs of the LA during sinus rhythm were collected in 22 patients undergoing AF ablation. The EAMs were co-registered with pre-ablation LGE-MRI models. Voltages in the areas with and without LGE were recorded. Left atrial volume index (LAVI) was calculated from MRI, and LAVI > 62 ml/m2 was defined as significant LA enlargement (LAE). RESULTS: Atrial bipolar voltage negatively correlates with the left atrial volume index. The median voltages in areas without LGE were 1.1 mV vs 2.0 mV in patients with vs without significant LAE (p = 0.002). In areas of LGE, median voltages were 0.4 mV vs 0.8 mV in patients with vs without significant LAE (p = 0.02). A voltage threshold of 1.7 mV predicted atrial LGE in patients with normal or mildly enlarged LA (sensitivity and specificity of 74% and 59%, respectively). In contrast, areas of voltage less than 0.75 mV correlated with LGE in patients with significant LA enlargement (sensitivity 68% and specificity 66%). CONCLUSIONS: LAVI affects left atrial bipolar voltage, and the correlation between low-voltage areas and LGE-MRI. Distinct voltage thresholds according to the LAVI value might be considered to identify atrial scar by EAM.

Smartphone AF Burden During the Blanking Period Predicts Catheter Ablation Outcomes: Insights From DECAAF II.

BACKGROUND: Atrial fibrillation (AF) recurrence during the blanking period is under investigated. With the rise of smartphone-based electrocardiogram (ECG) monitoring, there's potential for better prediction and understanding of AF recurrence trends. OBJECTIVES: In this study the authors hypothesize that AF burden derived from a single-lead Smartphone ECG during the blanking period predicts recurrence of atrial arrhythmias after ablation. METHODS: 630 patients with persistent AF undergoing ablation were included from the DECAAF II (Effect of MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation) trial. Patients recorded daily ECG strips using a smartphone device. AF burden was defined as the ratio of ECG strips with AF to the total number of strips submitted. The primary outcome was the recurrence of atrial arrhythmia. RESULTS: Recurrence occurred in 301 patients during the 18-month follow-up period. In patients who developed recurrent arrhythmia after 90 days of follow-up, AF burden during the blanking period was significantly higher when compared with patients who remained in sinus rhythm (31.3% vs 7.5%; P < 0.001). AF burden during the blanking period was an independent predictor of arrhythmia recurrence (HR: 1.41; 95% CI: 1.36-1.47; P < 0.001). Through grid searching, an AF burden of 18% best discriminates between recurrence and no-recurrence groups, yielding a C-index of 0.748. After a follow-up period of 18 months, recurrence occurred in 33.7% of patients (147 of 436) with an AF burden <18% and in 79.4% of patients (154 of 194) with an AF burden >18% (HR: 4.57; 95% CI: 3.63-5.75; P < 0.001). CONCLUSIONS: A high AF burden derived from a smartphone ECG during the blanking period is a strong predictor of atrial arrhythmia recurrences after ablation.

Early Remodeling of the Left Atrium Following Catheter Ablation of Atrial Fibrillation: Insights From DECAAFII.

BACKGROUND: Left atrial (LA) enlargement is prevalent among atrial fibrillation (AF) patients and constitutes an important marker of atrial myopathy. Several studies have described reduction in LA volume post-catheter ablation (CA) of AF, however, none have investigated differences related to additional ablation outside the pulmonary veins (PVs). OBJECTIVES: The authors sought to study early LA remodeling following CA of persistent AF and the impact of additional, fibrosis-guided extra-PV ablation. METHODS: In this DECAAF II (Effect of MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation) trial subanalysis, patients with persistent AF were randomized to receive pulmonary vein isolation (PVI) only or PVI + fibrosis-guided ablation. Late gadolinium enhancement magnetic resonance imaging (LGE-MRI) was performed before and 3 months after CA. Patients were followed up with single-lead electrocardiogram devices for 12 to18 months. AF burden was calculated as days with AF divided by days monitored. RESULTS: This analysis included 733 patients. The mean LA volume index (LAVI) before ablation was 62.0 mm3/m2 and after ablation was 51.3 mm3/m2, with a mean reduction of 10.7 mm3/m2 (P < 0.001). Patients in the fibrosis-guided ablation arm had more volume reduction than did those in the PVI-only group (12.1 mm3/m2 vs 9.3 mm3/m2; P = 0.02). LAVI reduction was greater in patients with heart failure (15.7 vs 8.9; P = 0.001) and was associated with improved left ventricular ejection fraction (LVEF) (r = 0.23; P < 0.001), reduced AF burden (r = -0.173; P < 0.001), improved LVEF, and improved quality of life (r = 0.146; P < 0.001). CONCLUSIONS: We confirmed the presence of LA remodeling within 3 months after ablation for persistent AF. Importantly, we saw more LA volume reductions in patients in the PVI + fibrosis-guided ablation arm in comparison with PVI only, and in patients with LV dysfunction. LA volume reduction in response to CA is associated with decreased arrhythmia recurrence, reduced AF burden, and improved LVEF and quality of life.

Catheter Ablation in End-Stage Heart Failure with Atrial Fibrillation.

BACKGROUND: The role of catheter ablation in patients with symptomatic atrial fibrillation and end-stage heart failure is unknown. METHODS: We conducted a single-center, open-label trial in Germany that involved patients with symptomatic atrial fibrillation and end-stage heart failure who were referred for heart transplantation evaluation. Patients were assigned to receive catheter ablation and guideline-directed medical therapy or medical therapy alone. The primary end point was a composite of death from any cause, implantation of a left ventricular assist device, or urgent heart transplantation. RESULTS: A total of 97 patients were assigned to the ablation group and 97 to the medical-therapy group. The trial was stopped for efficacy by the data and safety monitoring board 1 year after randomization was completed. Catheter ablation was performed in 81 of 97 patients (84%) in the ablation group and in 16 of 97 patients (16%) in the medical-therapy group. After a median follow-up of 18.0 months (interquartile range, 14.6 to 22.6), a primary end-point event had occurred in 8 patients (8%) in the ablation group and in 29 patients (30%) in the medical-therapy group (hazard ratio, 0.24; 95% confidence interval [CI], 0.11 to 0.52; P<0.001). Death from any cause occurred in 6 patients (6%) in the ablation group and in 19 patients (20%) in the medical-therapy group (hazard ratio, 0.29; 95% CI, 0.12 to 0.72). Procedure-related complications occurred in 3 patients in the ablation group and in 1 patient in the medical-therapy group. CONCLUSIONS: Among patients with atrial fibrillation and end-stage heart failure, the combination of catheter ablation and guideline-directed medical therapy was associated with a lower likelihood of a composite of death from any cause, implantation of a left ventricular assist device, or urgent heart transplantation than medical therapy alone. (Funded by Else Kröner-Fresenius-Stiftung; CASTLE-HTx ClinicalTrials.gov number, NCT04649801.).

Effect of MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation on Atrial Arrhythmia Recurrence in Patients With Persistent Atrial Fibrillation: The DECAAF II Randomized Clinical Trial.

Importance: Ablation of persistent atrial fibrillation (AF) remains a challenge. Left atrial fibrosis plays an important role in the pathophysiology of AF and has been associated with poor procedural outcomes. Objective: To investigate the efficacy and adverse events of targeting atrial fibrosis detected on magnetic resonance imaging (MRI) in reducing atrial arrhythmia recurrence in persistent AF. Design, Setting, and Participants: The Efficacy of Delayed Enhancement-MRI-Guided Fibrosis Ablation vs Conventional Catheter Ablation of Atrial Fibrillation trial was an investigator-initiated, multicenter, randomized clinical trial involving 44 academic and nonacademic centers in 10 countries. A total of 843 patients with symptomatic or asymptomatic persistent AF and undergoing AF ablation were enrolled from July 2016 to January 2020, with follow-up through February 19, 2021. Interventions: Patients with persistent AF were randomly assigned to pulmonary vein isolation (PVI) plus MRI-guided atrial fibrosis ablation (421 patients) or PVI alone (422 patients). Delayed-enhancement MRI was performed in both groups before the ablation procedure to assess baseline atrial fibrosis and at 3 months postablation to assess for ablation scar. Main Outcomes and Measures: The primary end point was time to first atrial arrhythmia recurrence after a 90-day blanking period postablation. The primary safety composite outcome was defined by the occurrence of 1 or more of the following events within 30 days postablation: stroke, PV stenosis, bleeding, heart failure, or death. Results: Among 843 patients who were randomized (mean age 62.7 years; 178 [21.1%] women), 815 (96.9%) completed the 90-day blanking period and contributed to the efficacy analyses. There was no significant difference in atrial arrhythmia recurrence between groups (fibrosis-guided ablation plus PVI patients, 175 [43.0%] vs PVI-only patients, 188 [46.1%]; hazard ratio [HR], 0.95 [95% CI, 0.77-1.17]; P = .63). Patients in the fibrosis-guided ablation plus PVI group experienced a higher rate of safety outcomes (9 [2.2%] vs 0 in PVI group; P = .001). Six patients (1.5%) in the fibrosis-guided ablation plus PVI group had an ischemic stroke compared with none in PVI-only group. Two deaths occurred in the fibrosis-guided ablation plus PVI group, and the first one was possibly related to the procedure. Conclusions and Relevance: Among patients with persistent AF, MRI-guided fibrosis ablation plus PVI, compared with PVI catheter ablation only, resulted in no significant difference in atrial arrhythmia recurrence. Findings do not support the use of MRI-guided fibrosis ablation for the treatment of persistent AF. Trial Registration: ClinicalTrials.gov Identifier: NCT02529319.

Effect of DrOnedarone on atrial fibrosis progression and atrial fibrillation recurrence postablation: Design of the EDORA randomized clinical trial.

BACKGROUND: Atrial fibrillation (AF) recurrence after catheter ablation is associated with worse outcomes and quality of life. Left atrial (LA) structural remodeling provides the essential substrate for AF perpetuation. Baseline extent and the progression of LA fibrosis after ablation are strong predictors of postprocedural AF recurrence. Dronedarone is an antiarrhythmic drug proven to efficiently maintain sinus rhythm. OBJECTIVE: We sought to investigate the effect of the antiarrhythmic drug Dronedarone in decreasing LA fibrosis progression and AF recurrence after ablation of AF patients. METHODS: EDORA (NCT04704050) is a multicenter, prospective, randomized controlled clinical trial. Patients with persistent or paroxysmal AF undergoing AF ablation will be randomized into Dronedarone versus placebo/standard of care. The co-primary outcomes are the recurrence of atrial arrhythmias (AA) within 13 months of follow-up after ablation and the progression of left atrial fibrosis postablation. All patients will receive a late-gadolinium enhancement magnetic resonance imaging at baseline, 3- and 12-month follow-up for the quantification of LA fibrosis and ablation-related scarring. AA recurrence and burden will be assessed using a 30-day ECG patch every 3 months with daily ECG recordings in between. Quality of life improvement is assessed using the AFEQT and AFSS questionnaires. CONCLUSION: EDORA will be the first trial to assess the progression of LA structural remodeling after ablation and its association with Dronedarone treatment and ablation success in a randomized controlled fashion. The trial will provide insight into the pathophysiology of AF recurrence after ablation and may provide potential therapeutic targets to optimize procedural outcomes.

Saturation recovery-prepared magnetic resonance angiography for assessment of left atrial and esophageal anatomy.

OBJECTIVES: Magnetic resonance angiography (MRA) has been established as an important imaging method in cardiac ablation procedures. In pulmonary vein (PV) isolation procedures, MRA has the potential to minimize the risk of severe complications, such as atrio-esophageal fistula, by providing detailed information on esophageal position relatively to cardiac structures. However, traditional non-gated, first-pass (FP) MRA approaches have several limitations, such as long breath-holds, non-uniform signal intensity throughout the left atrium (LA), and poor esophageal visualization. The aim of this observational study was to validate a respiratory-navigated, ECG-gated (EC), saturation recovery-prepared MRA technique for simultaneous imaging of LA, LA appendage, PVs, esophagus, and adjacent anatomical structures. METHODS: Before PVI, 106 consecutive patients with a history of AF underwent either conventional FP-MRA (n = 53 patients) or our new EC-MRA (n = 53 patients). Five quality scores (QS) of LA and esophagus visibility were assessed by two experienced readers. The non-parametric Mann-Whitney U-test was used to compare QS between FP-MRA and EC-MRA groups, and linear regression was applied to assess clinical contributors to image quality. RESULTS: EC-MRA demonstrated significantly better image quality than FP-MRA in every quality category. Esophageal visibility using the new MRA technique was markedly better than with the conventional FP-MRA technique (median 3.5 [IQR 1] vs median 1.0, p < 0.001). In contrast to FP-MRA, overall image quality of EC-MRA was not influenced by heart rate. CONCLUSION: Our ECG-gated, respiratory-navigated, saturation recovery-prepared MRA technique provides significantly better image quality and esophageal visibility than the established non-gated, breath-holding FP-MRA. Image quality of EC-MRA technique has the additional advantage of being unaffected by heart rate. ADVANCES IN KNOWLEDGE: Detailed information of cardiac anatomy has the potential to minimize the risk of severe complications and improve success rates in invasive electrophysiological studies. Our novel ECG-gated, respiratory-navigated, saturation recovery-prepared MRA technique provides significantly better image quality of LA and esophageal structures than the traditional first-pass algorithm. This new MRA technique is robust to arrhythmia (tachycardic, irregular heart rates) frequently observed in AF patients.

Managing Atrial Fibrillation in Patients With Heart Failure and Reduced Ejection Fraction: A Scientific Statement From the American Heart Association.

Atrial fibrillation and heart failure with reduced ejection fraction are increasing in prevalence worldwide. Atrial fibrillation can precipitate and can be a consequence of heart failure with reduced ejection fraction and cardiomyopathy. Atrial fibrillation and heart failure, when present together, are associated with worse outcomes. Together, these 2 conditions increase the risk of stroke, requiring oral anticoagulation in many or left atrial appendage closure in some. Medical management for rate and rhythm control of atrial fibrillation in heart failure remain hampered by variable success, intolerance, and adverse effects. In multiple randomized clinical trials in recent years, catheter ablation for atrial fibrillation in patients with heart failure and reduced ejection fraction has shown superiority in improving survival, quality of life, and ventricular function and reducing heart failure hospitalizations compared with antiarrhythmic drugs and rate control therapies. This has resulted in a paradigm shift in management toward nonpharmacological rhythm control of atrial fibrillation in heart failure with reduced ejection fraction. The primary objective of this American Heart Association scientific statement is to review the available evidence on the epidemiology and pathophysiology of atrial fibrillation in relation to heart failure and to provide guidance on the latest advances in pharmacological and nonpharmacological management of atrial fibrillation in patients with heart failure and reduced ejection fraction. The writing committee's consensus on the implications for clinical practice, gaps in knowledge, and directions for future research are highlighted.

Statistical shape analysis of the left atrial appendage predicts stroke in atrial fibrillation.

The shape of the left atrium (LA) and left atrial appendage (LAA) have been shown to predict stroke in patients with atrial fibrillation (AF). Prior studies rely on qualitative assessment of shape, which limits reproducibility and clinical utility. Statistical shape analysis (SSA) allows for quantitative assessment of shape. We use this method to assess the shape of the LA and LAA and predict stroke in patients with AF. From a database of AF patients who had previously undergone MRI of the LA, we identified 43 patients with AF who subsequently had an ischemic stroke. We also identified a cohort of 201 controls with AF who did not have a stroke after the MRI. We performed SSA of the LA and LAA shape to quantify the shape of these structures. We found three of the candidate LAA shape parameters to be predictive of stroke, while none of the LA shape parameters predicted stroke. When the three predictive LAA shape parameters were added to a logistic regression model that included the CHA2DS2-VASc score, the area under the ROC curve increased from 0.640 to 0.778 (p = .003). The shape of the LA and LAA can be assessed quantitatively using SSA. LAA shape predicts stroke in AF patients, while LA shape does not. Additionally, LAA shape predicts stroke independent of CHA2DS2-VASc score. SSA for assessment of LAA shape may improve stroke risk stratification and clinical decision making for AF patients.

Late Gadolinium Enhancement Magnetic Resonance Imaging Evaluation of Post-Atrial Fibrillation Ablation Esophageal Thermal Injury Across the Spectrum of Severity.

Background Esophageal thermal injury (ETI) is a byproduct of atrial fibrillation (AF) ablation using thermal sources. The most severe form of ETI is represented by atrioesophageal fistula, which has a high mortality rate. Late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) allows identification of ETI. Hence, we sought to evaluate the utility of LGE-MRI as a method to identify ETI across the entire spectrum of severity. Methods and Results All AF radiofrequency ablations performed at the University of Utah between January 2009 and December 2017 were reviewed. Patients with LGE-MRI within 24 hours following AF ablation as well as patients who had esophagogastroduodenoscopy in addition to LGE-MRI were identified. An additional patient with atrioesophageal fistula who had AF ablation at a different institution and had MRI and esophagogastroduodenoscopy at the University of Utah was identified. A total of 1269 AF radiofrequency ablations were identified. ETI severity was classified on the basis of esophageal LGE pattern (none, 60.9%; mild, 27.5%; moderate, 9.9%; severe, 1.7%). ETI resolved in most patients who underwent repeat LGE-MRI at 3 months. All patients with esophagogastroduodenoscopy-confirmed ETI had moderate-to-severe LGE 24 hours after ablation MRI. Moderate-to-severe LGE had 100% sensitivity and 58.1% specificity in detecting ETI, and a negative predictive value of 100%. Atrioesophageal fistula was visualized by both computed tomography and LGE-MRI in one patient. Conclusions LGE-MRI is useful in detecting and characterizing ETI across the entire severity spectrum. LGE-MRI exhibits an extremely high sensitivity and negative predictive value in screening for ETI after AF ablation.

Atrial Fibrillation Burden and Clinical Outcomes in Heart Failure: The CASTLE-AF Trial.

OBJECTIVES: This subanalysis of the CASTLE-AF (Catheter Ablation vs. Standard Conventional Treatment in Patients With LV Dysfunction and AF) trial aimed to address the association between atrial fibrillation (AF) recurrence, AF burden, and hard clinical outcomes in heart failure (HF) patients with AF. BACKGROUND: The CASTLE-AF trial demonstrated the benefit of CA compared to pharmacological treatment in decreasing mortality and CV hospitalizations in patients with AF and HFrEF. However, the impact of AF recurrence and AF burden after ablation on long-term treatment benefit remains unknown. METHODS: The CASTLE-AF protocol randomized 363 patients with coexisting HF and AF in a multicenter prospective controlled fashion to catheter ablation (n = 179) versus pharmacological therapy (n = 184). Two hundred eighty patients were included in this subanalysis (as-treated), 128 of them underwent ablation and 152 received pharmacological treatment. All patients had implanted dual chamber or biventricular implantable defibrillators with activated home monitoring capabilities. The individual AF burden was calculated as the percentage of the atrial arrhythmia time per day. RESULTS: AF burden at baseline was not predictive of the primary endpoint (p = 0.473) or all-cause mortality (p = 0.446). AF recurrence (defined as any episode >30 s) did not show any relationship with the primary endpoints of mortality and occurrence of HF, irrespective of the treatment arm. An AF burden below 50% after 6 months of catheter ablation, was associated with a significant decrease in primary composite outcome (hazard ratio [HR]: 0.33; 95% confidence interval [CI]: 0.15 to 0.71; p = 0.014) and all-cause mortality (HR: 0.23; 95% CI: 0.07 to 0.71; p = 0.031). The risk of the primary endpoint or mortality was directly related to a low (<50%) or high (≥50%) AF burden at 6 months post-ablation. CONCLUSIONS: AF burden at 6 months was predictive of hard clinical outcomes in HF patients with AF. The first recurrent atrial tachyarrhythmia episode >30 s after ablation was not associated with improvement in mortality and hospitalization for HF. (Catheter Ablation vs. Standard Conventional Treatment in Patients With LV Dysfunction and AF [CASTLE-AF]; NCT00643188).

Efficacy of LGE-MRI-guided fibrosis ablation versus conventional catheter ablation of atrial fibrillation: The DECAAF II trial: Study design.

INTRODUCTION: Success rates of catheter ablation in persistent atrial fibrillation (AF) remain suboptimal. A better and more targeted ablation strategy is urgently needed to optimize outcomes of AF treatment. We sought to assess the safety and efficacy of targeting atrial fibrosis during ablation of persistent AF patients in improving procedural outcomes. METHODS: The DECAAF II trial (ClinicalTrials. gov identifier number NCT02529319) is a prospective, randomized, multicenter trial of patients with persistent AF. Patients with persistent AF undergoing a first-time ablation procedure were randomized in a 1:1 fashion to receive conventional pulmonary vein isolation (PVI) ablation (Group 1) or PVI + fibrosis-guided ablation (Group 2). Left atrial fibrosis and ablation induced scarring were defined by late gadolinium enhancement magnetic resonance imaging at baseline and at 3-12 months postablation, respectively. The primary endpoint is the recurrence of atrial arrhythmia postablation, including atrial fibrillation, atrial flutter, or atrial tachycardia after the 90-day postablation blanking period. Patients were followed for a period of 12-18 months with a smartphone ECG Device (ECG Check Device, Cardiac Designs Inc.). With an anticipated enrollment of 900 patients, this study has an 80% power to detect a 26% reduction in the hazard ratio of the primary endpoint. RESULTS AND CONCLUSION: The DECAAF II trial is the first prospective, randomized, multicenter trial of patients with persistent AF using imaging defined atrial fibrosis as a treatment target. The trial will help define an optimal approach to catheter ablation of persistent AF, further our understanding of influencers of ablation lesion formation, and refine selection criteria for ablation based on atrial myopathy burden.

High-degree atrioventricular block in COVID-19 hospitalized patients.

AIMS: The novel coronavirus SARS-CoV-2 has shown the potential to significantly affect the cardiovascular system. Cardiac arrhythmias are commonly reported complications in COVID-19 hospitalized patients. METHODS AND RESULTS: While tachyarrhythmias seem most common, we describe four cases of COVID-19 patients who developed a transient high-degree atrioventricular (AV) block during the course of their hospitalization. All four patients who developed a high-degree AV block during their hospitalization with COVID-19 did not require permanent pacing. CONCLUSION: Similarly to most AV blocks associated with infectious organisms and given its transient nature, this case series suggests that conservative management strategies should be preferred in COVID-19 patients who develop complete heart block.

HRS White Paper on Clinical Utilization of Digital Health Technology.

This collaborative statement from the Digital Health Committee of the Heart Rhythm Society provides everyday clinical scenarios in which wearables may be utilized by patients for cardiovascular health and arrhythmia management. We describe herein the spectrum of wearables that are commercially available for patients, and their benefits, shortcomings and areas for technological improvement. Although wearables for rhythm diagnosis and management have not been examined in large randomized clinical trials, undoubtedly the usage of wearables has quickly escalated in clinical practice. This document is the first of a planned series in which we will update information on wearables as they are revised and released to consumers.

Pharmacological rhythm versus rate control in patients with atrial fibrillation and heart failure: the CASTLE-AF trial.

BACKGROUND: The value of antiarrhythmics to maintain normal sinus rhythm in patients with atrial fibrillation (AF) and heart failure (HF) is still being debated. We aimed to determine whether rhythm control using antiarrhythmic drugs (AADs) is more effective than rate control in improving outcomes in this population. METHOD: In this sub-analysis of the CASTLE-AF study, we included patients that were treated pharmacologically either to maintain sinus rhythm or to achieve rate control. The primary endpoint was defined as a composite of death from any cause or worsening of HF that led to an unplanned overnight hospitalization. RESULT: Among 210 patients (mean age of 64.1 ± 10.8 years, 83.3% male) treated pharmacologically, 60 patients were in the rhythm control group and 150 were in the rate control group. Patients in the rhythm control group were less likely to be assigned a beta-blocker (53 (88.3%) vs 141 (97.9%), P = 0.004) and digitalis (8 (13.3%) vs 53 (36.8%), P < 0.001). Over a median follow-up of 3.76 (95% confidence interval (CI), 3.23, 4.48) years, the primary composite endpoint of all-cause mortality and HF admissions occurred in 23 patients (38.3%) in the rhythm control arm vs 67 (44.7%) in the rate control arm (hazard ratio, 0.99; 95% CI, 0.62 to 1.60; P = 0.976). CONCLUSION: In CASTLE-AF among AF patients with HF, rhythm control with AADs did not significantly reduce the primary composite endpoint of all-cause mortality and HF hospitalization when compared with a pharmacological rate control strategy.

Catheter ablation for atrial fibrillation in patients with end-stage heart failure and eligibility for heart transplantation.

AIMS: Timely referrals for transplantation and left ventricular assist device (LVAD) play a key role in favourable outcomes in patients with advanced heart failure (HF). The purpose of the Catheter Ablation for atrial fibrillation in patientS with end-sTage heart faiLure and Eligibility for Heart Transplantation (CASTLE-HTx) trial is to test the hypothesis that atrial fibrillation (AF) ablation has beneficial effects on mortality and morbidity during 'waiting time' for heart transplantation (HTx) or to prolong the time span until LVAD implantation. METHODS AND RESULTS: CASTLE-HTx is a randomized evaluation of ablative treatment of AF in patients with severe left ventricular dysfunction who are candidates and eligible for HTx. The primary endpoint is the composite of all-cause mortality, worsening of HF requiring a high urgent transplantation, or LVAD implantation. The secondary study endpoints are all-cause mortality, cardiovascular mortality, cerebrovascular accidents, worsening of HF requiring unplanned hospitalization, AF burden reduction, unplanned hospitalization due to cardiovascular reason, all-cause hospitalization, quality of life, number of delivered implantable cardioverter defibrillator therapies, time to first implantable cardioverter defibrillator therapy, number of device-detected ventricular tachycardia/ventricular fibrillation episodes, left ventricular function, exercise tolerance, and percentage of right ventricular pacing. Ventricular myocardial tissue will be obtained from patients who will undergo LVAD implantation or HTx to assess the effect of catheter ablation on human HF myocardium. CASTLE-HTx will randomize 194 patients over a minimum time period of 2 years. CONCLUSIONS: CASTLE-HTx will determine if AF ablation has beneficial effects on mortality in patients with end-stage HF who are eligible for HTx.