Rate Control Strategy Research Articles

C31 NEXT GENERATION MYOCARDITIS

Abstract A 75–year–old overweight man, affected by hypertension, diabetes mellitus and atrial fibrillation since 2020. After 3 unsuccessful attempts of electrical cardioversion it was opted for a strategy of rate control with beta blocker and anticoagulant therapy with Rivaroxaban 20 mg. Following episodes of rectal bleeding; adenocarcinoma of the colon was diagnosed. The patient underwent hemicolectomy and started therapy with Pembrolizumab. The anticoagulant was replaced with Edoxaban 60 mg. In August 2022, he was admitted to the emergency department for severe signs and symptoms of heart failure. On ECG, atrial fibrillation with a heart rate of 90 bpm and non–specific changes in ventricular repolarization. The echocardiogram showed a severe reduction of the ejection fraction (FE 30%), which was not present at previous controls. On blood tests, troponins were negative and BNP increased. The patient underwent coronarography which was negative for significant lesions, and heart failure therapy was prescribed. Three months later the patient came to our cardio–oncology outpatient clinic; we repeated the echocardiogram which showed a recovery of the ejection fraction to 45% and planned a cardiac MRI. Cardiac MRI (CMR) showed global left ventricular hypokinesia (FE 42%) and late subepicardial gadoline enhancement in the basal segment of the inferior wall and transmural in the basal segment of the lateral wall without signs of oedema. Report described as compatible with myocarditis. The case was discussed collegially with radiologists and oncologists, and it was decided to discontinue immunotherapy (ICI). Myocarditis is the most common cardiovascular adverse events of ICI therapy, although it has a very low incidence. Generally, myocarditis related to ICI therapy has a high mortality rate and requires discontinuation of ICI. In addition, CMR may have a lower sensitivity in this setting. There is also a possibility of developing left ventricular dysfunction without associated myocarditis in the absence of increase in cardiac troponin and active myocardial inflammation at CMR. Although our case has been defined as myocarditis, it presents some unclear aspects due in part to the early non–diagnosis as a complication of ICI therapy. Although cancer patients taking ICI has expanded considerably in recent years, the evidence on cardiovascular complications is scarce and unknown to the clinical cardiologist.

Directing Reaction Pathways on Supported Metal Catalysts with Low-Density Self-Assembled Monolayers

Controlling reactant adsorption on catalyst surfaces is crucial to reaction activity and selectivity. One method for improving selectivity is by imposing steric constraints to bias the reactant binding orientation. In this study, thiol self-assembled monolayers (SAMs) were deposited onto Pt/Al2O3 catalysts as a method for controlling activity and selectivity via steric effects. In addition to a full monolayer, a low-density SAM-coated catalyst was employed. A number of characterization techniques demonstrated the successful deposition of homogeneous low-density SAMs on the metal surface with reduced site-blocking compared to a full high-density monolayer. Reaction kinetic studies showed increased benzyl alcohol hydrodeoxygenation (HDO) selectivity for both SAM-modified catalysts. This was attributed to the inability of the reactant to adsorb on the catalyst with the aromatic ring parallel to the surface, thus preventing decarbonylation and ring hydrogenation reaction pathways. Additionally, SAM density influenced reaction activity significantly, with the low-density-modified SAM catalyst being more active than the catalyst coated with a full monolayer. Moreover, liquid-phase hydrogenation reactions were used to investigate the relationship between SAM density and reactivity for reactant molecules of various sizes. In all cases, the low-density SAM improved reaction rates relative to dense SAMs. The effect of controlling ligand density depended on the type of reaction: high ligand densities greatly diminished ring hydrogenation, while HDO was largely unaffected, suggesting a potential strategy for size-selective reaction rate and selectivity control.

Atrial fibrillation and QT corrected. What is the best formula to use?

QT interval varies with the heart rate (HR), so a correction in QT calculation is needed (QTc). Atrial fibrillation (AF) is associated with elevated HR and beat-to-beat variation. To find best correlation between QTc in atrial fibrillation (AF) versus restored sinus rhytm (SR) after electrical cardioversion (ECV) (primary end point) and to determine which correction formula and method are the best to determine QTc in AF (secondary end point). During a 3-month period, we considered patients who underwent 12-lead ECG recording and received an AF diagnosis with indication for ECV. Exclusion criteria were as follows: QRS duration >120 ms, therapy with QT-prolonging drugs, a rate control strategy and a nonelectrical cardioversion. The QT interval was corrected using Bazzett's, Framingham, Fridericia and Hodges formulas during the last ECG during AF and the first one immediately after ECV. QTc mean was calculated as mQTc (average of 10 QTc calculated beat per beat) and as QTcM (QTc calculated from the average of 10 raw QT and RR for each beat). Fifty consecutive patients were enrolled in the study. Bazett's formula showed a significant change in mean QTc value between the two rhythms (421.5 ± 33.9 vs. 446.1 ± 31.9; p < 0.001 for mQTc and 420.9 ± 34.1 vs. 441.8 ± 30.9; p = 0.003 for QTcM). On the contrary, in patients with SR, QTc assessed by the Framingham, Fridericia, and Hodges formulas was similar to that in AF. Furthermore, good correlations between mQTc and QTcM are present for each formula, even in AF or SR. During AF, Bazzett's formula, seems to be the most imprecise in QTc estimation.

PO-04-081 ISOLATION OF PERSISTENT LEFT SIDED SUPERIOR VENA CAVA USING PULSED FIELD ABLATION

Pulmonary vein foci account for more than 90% of triggers for atrial fibrillation, most commonly treated with complete pulmonary vein isolation. Non–pulmonary vein triggers are the drivers of atrial fibrillation in a subgroup of patients. One such trigger is a persistent left superior vena cava (SVC), which may contain remnant muscular and pacemaker tissue carried over from embryonic life. However, reported complications of radiofrequency ablation of this structure are significant, including vein stenosis, tamponade and phrenic nerve injury. Pulsed field ablation is a promising new technology that may be uniquely suited to avoid such a complications. This case illustrates the first known application of pulsed field ablation of a left sided SVC. N/A The patient is a fifty-two year old male with a history of coronary artery disease and persistent atrial fibrillation refractory to medical therapy including rate and rhythm control strategies. He is status post multiple cardioversions with restoration to normal sinus rhythm for a relatively short period of time. The patient underwent an ablation procedure at which time it was discovered that he had an isolated persistent left sided SVC. Pulmonary vein isolation was performed using a combined radiofrequency and pulsed field ablation lattice tip catheter (Affera inc., Watertown, MA). Accordingly to study protocol, lesions were placed using radiofrequency anteriorly and pulsed field lesions posteriorly in the left atrium around the pulmonary veins resulting in complete isolation. The patient also developed a counterclockwise typical atrial flutter which was ablated. Given the propensity for triggers from the SVC, pulsed field ablation was performed by creating a circumferential lesion set superiorly beyond the left superior pulmonary vein region and inferiorly near the mid coronary sinus below the left inferior pulmonary vein. A linear lesion set connecting these two regions was also performed along the atrial portion of the coronary sinus, with subsequent confirmation of exit block and elimination of all local electrograms. In patients with persistent left SVC, pulsed field ablation is feasible without the risk of phrenic nerve injury or tamponade from excessive contact force. Further studies are necessary to examine whether the complications associated with LSVC isolation can be minimized.

Evaluation of Quantitative Decision-Making for Rhythm Management of Atrial Fibrillation Using Tabular Q-Learning.

Background Rhythm management is a complex decision for patients with atrial fibrillation (AF). Although clinical trials have identified subsets of patients who might benefit from a given rhythm-management strategy, for individual patients it is not always clear which strategy is expected to have the greatest mortality benefit or durability. Methods and Results In this investigation 52 547 patients with a new atrial fibrillation diagnosis between 2010 and 2020 were retrospectively identified. We applied a type of artificial intelligence called tabular Q-learning to identify the optimal initial rhythm-management strategy, based on a composite outcome of mortality, change in treatment, and sustainability of the given treatment, termed the reward function. We first applied an unsupervised learning algorithm using a variational autoencoder with K-means clustering to cluster atrial fibrillation patients into 8 distinct phenotypes. We then fit a Q-learning algorithm to predict the best outcome for each cluster. Although rate-control strategy was most frequently selected by treating providers, the outcome was superior for rhythm-control strategies across all clusters. Subjects in whom provider-selected treatment matched the Q-table recommendation had fewer total deaths (4 [8.5%] versus 473 [22.4%], odds ratio=0.32, P=0.02) and a greater reward (P=4.8×10-6). We then demonstrated application of dynamic learning by updating the Q-table prospectively using batch gradient descent, in which the optimal strategy in some clusters changed from cardioversion to ablation. Conclusions Tabular Q-learning provides a dynamic and interpretable approach to apply artificial intelligence to clinical decision-making for atrial fibrillation. Further work is needed to examine application of Q-learning prospectively in clinical patients.

The implantable cardiac monitor in heart failure patient: a possible new indication?

Implantable cardiac monitors (ICMs) have found increasing use in clinical practice over the years, proving, when used in high-risk populations, to facilitate the diagnosis of bradyarrhythmias and tachyarrhythmias requiring treatment. Experience with heart failure patients undergoing pacemaker (PMK) or implantable defibrillator (ICD) implantation, which allow for continuous electrocardiographic monitoring and transthoracic impedance assessment, has made it possible to identify predictors of heart failure flare-ups. In this context, the use of telemonitoring has been shown to ensure better management of patients with heart failure. These benefits cannot be assessed to date in patients with heart failure and left ventricular ejection fraction (LVEF) > 35% who have no indication for PMK or ICD implantation. This population has been shown to have a significant incidence of ventricular arrhythmias and bradyarrhythmias. In addition, a significant number of cerebrovascular events are observed in this population, largely attributable to the high incidence of atrial fibrillation (AF). In this population, the occurrence of AF has also been shown to have a negative impact on patients' prognosis; at the same time, a rhythm control strategy has been shown to be more beneficial in this area than a rate control strategy. Studies also suggest arrhythmias have a negative impact on the cognitive status and quality of life of heart failure patients. These reasons could justify the implantation of ICMs equipped with telemonitoring systems in heart failure patients. The information provided by the monitoring system, if properly managed, could bring benefits in terms of prognosis and quality of life along with a reduction in economic costs. We will try here, by answering a few questions, to assess whether there is an indication for ICM in heart failure, which patients should be candidates and how these patients should be managed.

Atrial fibrillation in heart failure: drugs or ablation?

Atrial fibrillation (AF) and heart failure (HF) frequently coexist and mutually exert negative influences with important clinical implications. Although there is evidence that restoring and maintaining sinus rhythm may have favourable clinical effects in patients with HF, there is no evidence of a survival benefit with pharmacological antiarrhythmic intervention compared with a heart rate control strategy. In these patients, transcatheter ablation (CA) of AF represents a procedure with an excellent safety profile in centres with expertise and a high volume of interventions. However, in the absence of definite evidence of benefit on major clinical end-points that can be generalized to the heterogeneous population with AF and HF, the option of CA should be discussed and shared with the patient, and mainly considered in patients with conditions that are associated with a greater prospect of clinical benefit, such as 'young' age (65-70 years), good health conditions and few or no comorbidities, recent onset of HF and AF (especially if with high heart rate), left atrial volume not excessively compromised (<55 mm in diameter), and without evidence of substantial fibrotic remodelling, left ventricular ejection fraction (LVEF) >25%, including HF with preserved EF (HFpEF).

Secure Information Sharing Approach for Internet of Vehicles Based on DAG-Enabled Blockchain

Information sharing in vehicular networks has great potential for the future Internet of Vehicles (IoV). Vehicles and roadside units (RSUs) can exchange perceptual information and driving experience to enable intelligent transportation applications such as autonomous driving and road condition analysis. However, ensuring secure and efficient information sharing among vehicles is challenging. While traditional blockchain can guarantee the tamper-proof nature of shared information, it cannot be directly applied in large-scale vehicle networks due to its slow consensus process. Therefore, we propose an information sharing approach based on a directed acyclic graph (DAG), in which shared information is encapsulated into sites instead of blocks. We also propose a driving decision-based tip selection algorithm (DDB-TSA) and design a reputation-based rate control strategy (RBRCS) to ensure secure and efficient information sharing. Simulation results show that our approach reduces consensus latency, improves information sharing efficiency, and provides a more secure information sharing environment compared to existing DAG-enabled blockchain systems.

Lenient rate control versus strict rate control for atrial fibrillation: a statistical analysis plan for the Danish Atrial Fibrillation (DanAF) randomized clinical trial

BackgroundA key decision in the treatment of atrial fibrillation is choosing between a rhythm control strategy or a rate control strategy as the main strategy. When choosing rate control, the optimal heart rate target is uncertain. The Danish Atrial Fibrillation trial is a randomized, multicenter, two-group, superiority trial comparing strict rate control versus lenient rate control in patients with either persistent or permanent atrial fibrillation at inclusion. To prevent bias arising from selective reporting and data-driven analyses, we developed a predefined description of the statistical analysis.MethodsThe primary outcome of this trial is the physical component score of the SF-36 questionnaire. A total of 350 participants will be enrolled based on a minimal important difference of 3 points on the physical component score of the SF-36 questionnaire, a standard deviation of 10 points, a statistical power of 80% (beta of 20%), and an acceptable risk of type I error of 5%. All secondary, exploratory, and echocardiographic outcomes will be hypothesis-generating. The analyses of all outcomes will be based on the intention-to-treat principle. We will analyze continuous outcomes using linear regression adjusting for “site,” type of atrial fibrillation at inclusion (persistent/ permanent), left ventricular ejection fraction (≥ 40% or < 40%), and the baseline value of the outcome (all as fixed effects). We define our threshold for statistical significance as a p-value of 0.05 and assessments of clinical significance will be based on the anticipated intervention effects defined in the sample size and power estimations. Thresholds for both statistical and clinical significance will be assessed according to the 5-step procedure proposed by Jakobsen and colleagues.DiscussionThis statistical analysis plan will be published prior to enrolment completion and before any data are available and is sought to increase the validity of the DANish Atrial Fibrillation trial.Trial registrationClinicaltrials.gov NCT04542785. Registered on Sept 09, 2020.

Patients with Rapid Atrial Fibrillation in Congestive Heart Failure with Bilateral Pleural Effusion Complication: Case Report and Literature Review

Highlights: In the setting of AF in patient with AHF, conventional treatment strategies do not convert the rhythm into sinus rhythm. Newly emerged therapies such as catheter ablation, or atrioventricular node ablation with biventricular pacing might be more beneficial rather than the conventional rhythm and rate control strategies Abstract: Atrial fibrillation (AF) is the most common form of arrhythmia. The prevalence of AF in patients with systolic left ventricular dysfunction and CHF is around 35% in the patient population with NYHA II-IV. In this case, we will discuss a case report of a patient with AF with complications of CHF and Bilateral Pleural Effusion. Case Summary. A female patient, 62 years old, came to the emergency room of dr. Soegiri Hospital with complaints of sudden shortness of breath since morning. There were crackles in the right lung field during the auscultation and the chest x-ray shows cardiomegaly with a CTR&gt; 50% with bilateral effusion and atelectasis. On the electrocardiogram examination performed at the ICCU, an irregular rhythm was obtained with an HR of 100x/minute, with p waves that cannot be distinguished, normal QRS waves, and T waves that cannot be assessed. The patient was diagnosed with congestive heart failure (CHF) with rapid atrial fibrillation (AF) accompanied by complications of bilateral pleural effusion with a differential diagnosis of acute decompensated heart failure (ADHF) with pneumonia and acute lung edema (ALO). Discussion. Patients with AF and CHF have a poorer prognosis than patients with a single diagnosis of AF or CHF alone. A rhythm control strategy consisting of antiarrhythmic drugs and electrical cardioversion in stable patients with AF and CHF adds no benefit to a heart rate control strategy.

The impact of rate and rhythm control strategies on quality of life for patients with atrial fibrillation: a protocol for a systematic review

BackgroundAtrial fibrillation (AF) is the most common heart arrhythmia globally and it adversely affects the quality of life (QoL). Available rate and rhythm control strategies equally reduce mortality but may impact QoL differently. A number of systematic reviews have focused on the impact of specific strategies on QoL, though a 2006 review synthesized the evidence on the effect of all strategies on QoL, allowing for a clinically important comparison between the types of strategies. Many trials have been published since the review undertook the search in 2005; therefore, an update is needed. This systematic review aims to provide an update to the 2006 review on the impact of all rate and rhythm control strategies on QoL in people with AF.MethodsThe following four databases and three clinical trial registries will be searched for primary studies: CENTRAL, MEDLINE, Embase, CINAHL, WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, and ClinicalTrialsRegister.eu. No language restriction will be applied. The search will be limited to 2004 or later publication year to allow overlap with the search conducted by the 2006 review authors. Any randomized control trial that reports the QoL of adult (≥ 18 years) AF patients following an eligible rate or rhythm control intervention will be eligible for inclusion. Eligible interventions (and comparators) include pacing, atrioventricular node junction and bundle of HIS ablation, pharmacological therapy, radio frequency catheter ablation, cryoablation, pulmonary vein isolation, maze operation, pace maker implantation, and defibrillator implantation. Two reviewers will independently screen for eligible studies, extract the data using a piloted tool, and assess bias by QoL outcome using the RoB 2 tool. The suitability of conducting a meta-analysis will be assessed by the clinical and methodology similarities of included studies. If it is feasible, standardized mean differences will be pooled using a random-effects model and assessed appropriately.DiscussionThe findings from this review will allow for meaningful comparisons between various rate and rhythm control strategies regarding their impact on QoL. This review will be useful for a wide range of stakeholders and will be crucial for optimizing the overall wellbeing of AF patients.Systematic review registrationPROSPERO CRD42021290542

Atrial Fibrillation Occurring During Acute Hospitalization: A Scientific Statement From the American Heart Association

Acute atrial fibrillation is defined as atrial fibrillation detected in the setting of acute care or acute illness; atrial fibrillation may be detected or managed for the first time during acute hospitalization for another condition. Atrial fibrillation after cardiothoracic surgery is a distinct type of acute atrial fibrillation. Acute atrial fibrillation is associated with high risk of long-term atrial fibrillation recurrence, warranting clinical attention during acute hospitalization and over long-term follow-up. A framework of substrates and triggers can be useful for evaluating and managing acute atrial fibrillation. Acute management requires a multipronged approach with interdisciplinary care collaboration, tailoring treatments to the patient's underlying substrate and acute condition. Key components of acute management include identification and treatment of triggers, selection and implementation of rate/rhythm control, and management of anticoagulation. Acute rate or rhythm control strategy should be individualized with consideration of the patient's capacity to tolerate rapid rates or atrioventricular dyssynchrony, and the patient's ability to tolerate the risk of the therapeutic strategy. Given the high risks of atrial fibrillation recurrence in patients with acute atrial fibrillation, clinical follow-up and heart rhythm monitoring are warranted. Long-term management is guided by patient substrate, with implications for intensity of heart rhythm monitoring, anticoagulation, and considerations for rhythm management strategies. Overall management of acute atrial fibrillation addresses substrates and triggers. The 3As of acute management are acute triggers, atrial fibrillation rate/rhythm management, and anticoagulation. The 2As and 2Ms of long-term management include monitoring of heart rhythm and modification of lifestyle and risk factors, in addition to considerations for atrial fibrillation rate/rhythm management and anticoagulation. Several gaps in knowledge related to acute atrial fibrillation exist and warrant future research.

Choice of sinus rhythm control strategy in patients with atrial fibrillation: why, when and how? A review

After 20 years of dubious notions of parity between sinus rhythm control and ventricular rate control strategies in patients with atrial fibrillation, there is evidence of the prognostic superiority of the former. The review article presents the results of randomized trials that support early rhythm control in patients with atrial fibrillation, possible pharmacological and non-pharmacological methods of such treatment in real clinical practice.

Self-paced heart rate control for treadmill exercise

Introduction: With conventional heart rate (HR) control systems, the exercising person is bound to walk or run at a pace determined by the feedback. This may be challenging for people with impairments that make it difficult for them to achieve a smooth, continuous pace. The aim of this work was to assess the technical feasibility of a novel self-paced heart rate control strategy and to compare its accuracy with conventional heart rate control.Methods: We propose a self-paced heart rate control system that embeds an automatic positioning controller within the heart rate control loop. The treadmill speed command is decoupled from the heart rate compensator, whereas speed is determined by the exerciser’s own volition: target speed is displayed visually to the person and, when they try to follow this target, the position controller sets the treadmill speed while keeping the person at a safe reference position on the track. A further novel contribution of this work is a new input-sensitivity-shaping, frequency-domain design strategy for feedback control of position.Results: Experimental evaluation with four participants showed that self-paced heart rate control is technically feasible: all participants were able to accurately follow the target running speed calculated by the HR compensator and presented to them visually; for all four participants, self-paced HR tracking accuracy was not substantially different from conventional HR control performance; on average, the self-paced heart rate controller gave slightly better performance than conventional HR control, with RMS tracking error of 2.98 beats per minute (bpm) vs 3.11 bpm and higher average control signal power.Conclusion: The proposed self-paced heart rate control strategy with embedded automatic position control is deemed feasible. This approach may be helpful for people with gait impairments or other limitations that make it difficult for them to follow an imposed treadmill speed.

Rate Control in Versatile Video Coding with Cosh Rate–Distortion Model

In this paper, we propose a rate control (RC) scheme for versatile video coding (VVC) to enhance coding performance. First, we propose a rate–distortion (R–D) model at the coding tree unit (CTU) level to describe the R–D relationship. Second, we adjust the quantization parameter (QP) and Lagrange multiplier at the coding unit (CU) level according to visual features to improve the rationality of local coding results. Finally, we propose a model parameter updating strategy to guarantee bitrate accuracy. The experimental results demonstrate that our RC method has better R–D performance with similar bitrate accuracy and better visual quality compared to the default RC strategy in VVC reference software VTM 10.2.

Factors predictive of spontaneous reversion to sinus rhythm: Findings from an integrated acute atrial fibrillation pathway

Recent evidence suggests that delayed cardioversion of uncomplicated acute AF is non-inferior to early cardioversion in the Emergency Department (ED), 1 Pluymaekers N.A.H.A. Dudink E.A.M.P. Luermans J.G.L.M. et al. Early or Delayed Cardioversion in Recent-Onset Atrial Fibrillation. N Engl J Med. 2019; 380: 1499-1508 Crossref PubMed Scopus (95) Google Scholar and most patients will revert spontaneously to sinus rhythm (SR) by a rate control strategy. 2 Abadie B.Q. Hansen B. Walker J. et al. Likelihood of Spontaneous Cardioversion of Atrial Fibrillation Using a Conservative Management Strategy Among Patients Presenting to the Emergency Department. Am J Cardiol. 2019; 124: 1534-1539 Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar We adopted a new inter-departmental acute AF clinical pathway 3 Al-Busaidi I.S. Clare G.C. Joyce L.R. et al. Presentation, Treatment and Long-Term Outcomes of a Multidisciplinary Acute Atrial Fibrillation Pathway: A 12-Month Follow-Up Study. Heart Lung Circ. 2022; 31: 216-223 Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar in 2015 which involves a ‘rate-and-wait’ strategy where patients are managed with rate control agents followed by a review in a ward-based clinic within 24-72 hours (97% attend within this time frame). Over two-thirds (71%) of pathway patients spontaneously reverted to SR by clinic review. 3 Al-Busaidi I.S. Clare G.C. Joyce L.R. et al. Presentation, Treatment and Long-Term Outcomes of a Multidisciplinary Acute Atrial Fibrillation Pathway: A 12-Month Follow-Up Study. Heart Lung Circ. 2022; 31: 216-223 Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar We examined predictors of spontaneous reversion to SR at AF clinic follow-up.

Impact of frailty on early rhythm control outcomes in older adults with atrial fibrillation: A nationwide cohort study.

Rhythm-control therapy administered early following the initial diagnosis of atrial fibrillation (AF) has superior cardiovascular outcomes compared to rate-control therapy. Frailty is a key factor in identifying older patients' potential for improvement after rhythm-control therapy. This study evaluated whether frailty affects the outcome of early rhythm-control therapy in older patients with AF. From the Korean National Health Insurance Service database (2005-2015), we collected 20,611 populations aged ≥65 years undergoing rhythm- or rate-control therapy initiated within 1 year of AF diagnosis. Participants were emulated by the EAST-AFNET4 trial, and stratified into non-frail, moderately frail, and highly frail groups based on the hospital frailty risk score (HFRS). A composite outcome of cardiovascular-related mortality, myocardial infarction, hospitalization for heart failure, and ischemic stroke was compared between rhythm- and rate-control. Early rhythm-control strategy showed a 14% lower risk of the primary composite outcome in the non-frail group [weighted incidence 7.3 vs. 8.6 per 100 person-years; hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.79-0.93, p < 0.001] than rate-control strategy. A consistent trend toward a lower risk of early rhythm-control was observed in the moderately frail (HR 0.91, 95% CI 0.81-1.02, p = 0.09) and highly frail (HR 0.93, 95% CI 0.75-1.17, p = 0.55) groups. Although the degree attenuated with increasing frailty, the superiority of cardiovascular outcomes of early rhythm-control in AF treatment was maintained without increased risk for safety outcomes. An individualized approach is required on the benefits of early rhythm-control therapy in older patients with AF, regardless of their frailty status.

Atrio-ventricular nodal ablation with biventricular pacing in atrial fibrillation with narrow QRS – a novel strategy to reduce mortality independent of underling left ventricular function.

Historically, clinical studies have demonstrated conflicting results for rate-control versus rhythm-control strategy in patients with permanent atrial fibrillation (AF) in terms of long-term mortality and morbidity. The concept of atrioventricular (AV) nodal ablation coupled with permanent biventricular pacing has recently been advocated as the closest approach to obtain a physiological reset especially in AF patients having underlying ventricular dysfunction. Herein, we present a critical analysis and detailed review based on prior and currently available evidence based on the ablation in permanent atrial fibrillation – cardiac resynchronization therapy (APAF-CRT) mortality trial.

A Distributed Rate-Control Approach to Reduce Communication Burdens in VSNs

In visual sensor networks, the analyze-then-compress paradigm, where each camera process data and extract local features, is proved to be an efficient approach to reduce the amount of transmitted information. The bitrate can be further reduced by efficiently compressing the extracted features using a distributed feature coding technique. However, since the rate control is performed at the decoder, an abundant use of the feedback channel is needed to adjust the coding rate. Moreover, transmitting all extracted features, including irrelevant ones with no further contribution to the application accuracy, overloads the network. In this paper, we propose a novel feature selection and distributed coding rate control strategies that cope with these issues. The proposed strategies are designed to significantly reduce the transmitted bitrate and the communication burden with the sink, which implicitly reduces the energy consumption and the decoding delay. We show that, wisely selecting at the camera sensors level only the features effectively contributing to the application accuracy reduces the amount of transmitted information up to 34% while preserving accuracy. Furthermore, the cameras can collaborate periodically, by exchanging small amount of information about their selected features, to estimate the minimum transmission rate required for each feature based on a linear fitting model that takes into consideration the inter-camera correlation and the channel conditions. Significant average bitrate savings, reaching up to 37.71%, are achieved.

130: CALCIUM CHANNEL BLOCKERS VERSUS BETA BLOCKERS FOR ACUTE RATE CONTROL IN HEART FAILURE PATIENTS

Introduction: A rate control strategy is often pursued for management of new-onset atrial fibrillation and a rapid ventricular rate (RVR) in heart failure with reduced ejection fraction (HFrEF) patients. Either a beta blocker (BB) or non-dihydropyridine calcium channel blocker (non-DHP CCB) can be used, however, non-DHP CCBs may worsen heart failure through negative inotropic effects. This study was conducted to compare short-term use of BBs with non-DHP CCBs on the incidence of heart failure exacerbation. Methods: This was a multi-site, retrospective cohort study conducted at a 2,247-bed community teaching hospital system in the United States. Adult patients presenting to the emergency department for atrial fibrillation with RVR were included if they had new-onset or a history of HFrEF and received a non-DHP CCB or BB for less than 48 hours. Hemodynamically unstable patients were excluded. The primary outcome was the incidence of heart failure exacerbation within 48 hours of drug administration, defined by a combination of provider documentation and at least one clinical or laboratory marker. Additional efficacy and safety endpoints were assessed secondarily. Results: Between March 2018 and January 2021, 1,519 patients were screened and 164 included (113 in the non-DHP CCB group and 51 in the BB group). The median age was 70 years and 70% were male. The median dose of non-DHP CCB at 48 hours was 90 mg and the median duration was 13 hours. In the BB group, the median dose and duration was 5 mg and 6 hours, respectively. Eleven patients receiving a non-DHP CCB and 1 patient receiving a BB met the primary outcome (p=0.08). Patients who had a heart failure exacerbation in the non-DHP CCB group received both a higher median dose (190 mg) and longer median duration (21 hours) of therapy. Additionally, 6 patients in the non-DHP CCB group and 1 in the BB group experienced an exacerbation within 7 days (p=0.33). More patients in the non-DHP CCB group experienced bradycardia (23% vs 5.9%, p=0.008), however, there were no other differences in safety or efficacy. Conclusions: While not statistically significant, there were numerically more incidences of heart failure exacerbations in HFrEF patients receiving non-DHP CCBs compared with BBs for acute rate control.