Association of Neighborhood-Level Material Deprivation With Atrial Fibrillation Care in a Single-Payer Health Care System: A Population-Based Cohort Study.

BACKGROUND: There are limited data on the association of material deprivation with clinical care and outcomes after atrial fibrillation (AF) diagnosis in jurisdictions with universal health care. METHODS: This was a population-based cohort study of individuals ≥66 years of age with first diagnosis of AF between April 1, 2007, and March 31, 2019, in the Canadian province of Ontario, which provides public funding and prohibits private payment for medically necessary physician and hospital services. Prescription medications are subsidized for residents >65 years of age. The primary exposure was neighborhood material deprivation, a metric derived from Canadian census data to estimate inability to attain basic material needs. Neighborhoods were categorized by quintile from Q1 (least deprived) to Q5 (most deprived). Cause-specific hazards regression was used to study the association of material deprivation quintile with time to AF-related adverse events (death or hospitalization for stroke, heart failure, or bleeding), clinical services (physician visits, cardiac diagnostics), and interventions (anticoagulation, cardioversion, ablation) while adjusting for individual characteristics and regional cardiologist supply. RESULTS: Among 347 632 individuals with AF (median age 79 years, 48.9% female), individuals in the most deprived neighborhoods (Q5) had higher prevalence of cardiovascular disease, risk factors, and noncardiovascular comorbidity relative to residents of the least deprived neighborhoods (Q1). After adjustment, Q5 residents had higher hazards of death (hazard ratio [HR], 1.16 [95% CI, 1.13-1.20]) and hospitalization for stroke (HR, 1.16 [95% CI, 1.07-1.27]), heart failure (HR, 1.14 [95% CI, 1.11-1.18]), or bleeding (HR, 1.16 [95% CI, 1.07-1.25]) relative to Q1. There were small differences across quintiles in primary care physician visits (HR, Q5 versus Q1, 0.91 [95% CI, 0.89-0.92]), echocardiography (HR, Q5 versus Q1, 0.97 [95% CI, 0.96-0.99]), and dispensation of anticoagulation (HR, Q5 versus Q1, 0.97 [95% CI, 0.95-0.98]). There were more prominent disparities for Q5 versus Q1 in cardiologist visits (HR, 0.84 [95% CI, 0.82-0.86]), cardioversion (HR, 0.80 [95% CI, 0.76-0.84]), and ablation (HR, 0.45 [95% CI, 0.30-0.67]). CONCLUSIONS: Despite universal health care and prescription medication coverage, residents of more deprived neighborhoods were less likely to visit cardiologists or receive rhythm control interventions after AF diagnosis, even though they exhibited higher cardiovascular disease burden and higher risk of adverse outcomes.

Is There a Role for Vitamin K Antagonist in the Management of Atrial Fibrillation in 2023?

PURPOSE OF REVIEW: To address the following question: Are vitamin K antagonists (VKA) obsolete as stroke prevention therapy for patients with atrial fibrillation (AF) and thromboembolic risk factors? RECENT FINDINGS: A patient-level meta-analysis of the pivotal phase III randomized trials confirmed the favorable treatment effect of direct oral anticoagulants (DOAC) over VKA in multiple key patient subgroups. Among patients with AF and rheumatic heart disease (85% of whom had mitral stenosis), a randomized trial showed that rivaroxaban was not superior to VKA for stroke prevention. Caution should be exercised when prescribing DOAC for AF-related stroke prevention for patients with elevated body mass indices or history of bariatric surgery, patients with bioprosthetic heart valves, and those who require treatment with drugs that interact with cytochrome P450 and P-glycoprotein. Drug costs associated with DOAC remain considerably higher than VKA, by up to 30-fold. Direct oral anticoagulants are preferable over VKA in the large majority of eligible patients with AF and thromboembolic risk factors. The use of DOAC should be avoided for patients with mechanical heart valves or moderate/severe rheumatic mitral stenosis. Vitamin K antagonist is a reasonable option for patients who are under-represented in randomized trials, when there are significant drug-drug interactions or when patients cannot afford DOAC agents due to their higher costs.

Focal and pseudo/rotational activations in human atrial fibrillation defined with automated periodicity mapping.

INTRODUCTION: Defining atrial fibrillation (AF) wave propagation is challenging unless local signal features are discrete or periodic. Periodic focal or rotational activity may identify AF drivers. Our objective was to characterize AF propagation at sites with periodic activation to evaluate the prevalence and relationship between focal and rotational activation. METHODS: We included 80 patients (61 ± 10 years, persistent AF 49%) from the FaST randomized trial that compared the efficacy of adjunctive focal site ablation versus pulmonary vein isolation. Patients underwent left atrial (LA) activation mapping with a 20-pole circular catheter during spontaneous or induced AF. Five-second bipolar and unipolar electrograms in AF were analyzed. Periodic sites were identified by spectral analysis of the bipolar electrogram. Activation maps of periodic sites were constructed using an automated, validated tracking algorithm, and classified into three patterns: focal sites (FS), rotation (RO), or pseudo-rotation (pRO). RESULTS: The most common propagation pattern at periodic sites was FS for 5-s in all patients (4.9 ± 1.9 per patient). RO and pRO were observed in two and seven patients, respectively, but were all transient (3-5 cycles). Activation from a FS evolved into transient RO/pRO in five patients. No patient had autonomous RO/pRO activations. Patients with RO/pRO had greater LA surface area with periodicity (78 ± 7 vs. 63 ± 16%, p = .0002) and shorter LA periodicity CL (166 ± 10 vs. 190±28 ms, p = .0001) than the rest. CONCLUSION: Using automated, regional AF periodicity mapping, FS is more prevalent and temporally stable than RO/pRO. Most RO/pRO evolve from neighboring FS. These findings and their implications for AF maintenance require verification with global, panoramic mapping.

Unipolar electrogram-based voltage mapping with far-field cancellation to improve detection of abnormal atrial substrate during atrial fibrillation.

INTRODUCTION: An important substrate for atrial fibrillation (AF) is fibrotic atrial myopathy. Identifying low voltage, myopathic regions during AF using traditional bipolar voltage mapping is limited by the directional dependency of wave propagation. Our objective was to evaluate directionally independent unipolar voltage mapping, but with far-field cancellation, to identify low-voltage regions during AF. METHODS: In 12 patients undergoing pulmonary vein isolation for AF, high-resolution voltage mapping was performed in the left atrium during sinus rhythm and AF using a roving 20-pole circular catheter. Bipolar electrograms (EGMs) (Bi) < 0.5 mV in sinus rhythm identified low-voltage regions. During AF, bipolar voltage and unipolar voltage maps were created, the latter with (uni-res) and without (uni-orig) far-field cancellation using a novel, validated least-squares algorithm. RESULTS: Uni-res voltage was ~25% lower than uni-orig for both low voltage and normal atrial regions. Far-field EGM had a dominant frequency (DF) of 4.5-6.0 Hz, and its removal resulted in a lower DF for uni-orig compared with uni-res (5.1 ± 1.5 vs. 4.8 ± 1.5 Hz; p < .001). Compared with Bi, uni-res had a significantly greater area under the receiver operator curve (0.80 vs. 0.77; p < .05), specificity (86% vs. 76%; p < .001), and positive predictive value (43% vs. 30%; p < .001) for detecting low-voltage during AF. Similar improvements in specificity and positive predictive value were evident for uni-res versus uni-orig. CONCLUSION: Far-field EGM can be reliably removed from uni-orig using our novel, least-squares algorithm. Compared with Bi and uni-orig, uni-res is more accurate in detecting low-voltage regions during AF. This approach may improve substrate mapping and ablation during AF, and merits further study.

Impact of electrical cardioversion on quality of life for patients with symptomatic persistent atrial fibrillation: Is there a treatment expectation effect?

It is assumed that electrical cardioversion (ECV) improves the quality of life (QoL) of patients with atrial fibrillation (AF) by restoring sinus rhythm (SR). OBJECTIVE: We examined the effect of ECV and rhythm status on QoL of patients with symptomatic persistent AF in a randomized controlled trial. METHOD: The elective cardioversion for prevention of symptomatic atrial fibrillation trial examined the efficacy of dronedarone around the time of ECV in maintaining SR. Quality of life was measured with the University of Toronto Atrial Fibrillation Severity Scale. The primary outcome was the change in AF symptom severity (∆AFSS) score over 6 months (0-35 points, with higher scores reflecting worse QoL and a minimal clinically important difference defined as ∆AFSS ≥3 points). Multivariable linear regression was performed to identify factors associated with changes in QoL. RESULTS: We included 148 patients with complete AFSS scores at baseline and 6 months. Over 6 months, QoL improved irrespective of rhythm status (ΔAFSS scores for patients who (i) maintained SR; (ii) had AF relapse after successful ECV; and (iii) had unsuccessful ECV were -6.8 ±â€¯6.4 points, -4.1 ±â€¯6.2 points, and -4.0 ±â€¯5.8 points respectively, P < .01 for all subgroups). After adjustment of baseline covariates, maintenance of SR was associated with QoL improvement (ΔAFSS: -3.8 points, 95% CI: -6.0 to -1.6 points, P < .01). CONCLUSIONS: Maintenance of SR was associated with clinically relevant improvement in patients' QoL at 6 months. Patients with AF recurrence had a small but still relevant improvement in their QoL, potentially due to factors other than sinus rhythm.

The more you look, the more you find: atrial fibrillation - nowhere to hide.

PURPOSE OF REVIEW: We provide an updated review on the incidence of postoperative atrial fibrillation (POAF) after cardiac surgery as determined by enhanced cardiac rhythm monitoring technology and provide a rationale for why a more aggressive detection approach for POAF may be clinically useful. RECENT FINDINGS: Most of the published literature had focused on the in-hospital incidence of POAF after cardiac surgery. However, recent studies using continuous cardiac rhythm technologies revealed that the incidence of POAF during the postdischarge, subacute (<1 month) phase could be as high as 28%. This is a clinically relevant finding since that POAF is linked with occurrence of future, 'late' atrial fibrillation, and adverse clinical outcomes even beyond 1 year after cardiac surgery. Furthermore, the role of oral anticoagulation is still not well established for cardiac surgical patients with POAF because of lack of randomized trials specifically designed for this patient population. SUMMARY: Emerging data suggest that POAF after cardiac surgery is not a transient, self-resolving phenomenon. Rather, its occurrence is associated with future risk of atrial fibrillation and long-term adverse outcomes such as stroke and death. This highlights the potential importance of enhanced cardiac rhythm monitoring to refine prognostic stratification in this high-risk patient population.

The Optimal Anti-Coagulation for Enhanced-Risk Patients Post-Catheter Ablation for Atrial Fibrillation (OCEAN) trial.

BACKGROUND: The optimal long-term antithrombotic regimen for patients after successful catheter-based atrial fibrillation (AF) ablation is not well defined. Presently, practice variation exists, and the benefits of oral anticoagulation over antiplatelet therapy across the entire spectrum of stroke risk profile remain undefined in the postablation population. To date, there are no randomized trials to inform clinicians on this therapeutic question. OBJECTIVE: The objective was to assess whether rivaroxaban is superior to acetylsalicylic acid (ASA) in reducing the risk of clinically overt stroke, systemic embolism, or covert stroke among patients without apparent recurrent atrial arrhythmias for at least 1 year after their most recent AF ablation procedure. METHODS/DESIGN: A prospective, multicenter, open-label, randomized trial with blinded assessment of outcomes is under way (NCT02168829). Atrial fibrillation patients with at least 1 stroke risk factor (as defined by the CHA2DS2-VASc score) and without known atrial arrhythmia recurrences for at least 12 months after ablation are randomized to rivaroxaban 15 mg or ASA 75-160 mg daily. The primary outcome is a composite of clinically overt stroke, systemic embolism, and covert stroke based on brain magnetic resonance imaging. Key secondary outcomes include major bleeding outcomes, intracranial hemorrhage, transient ischemic attack, neuropsychological testing, quality of life, and an economic analysis. Subjects will be followed for 3 years. The estimated overall sample size is 1,572 subjects (786 per arm). DISCUSSION: The OCEAN trial is a multicenter randomized controlled trial evaluating 2 antithrombotic treatment strategies for patients with risk factors for stroke after apparently successful AF ablation. We hypothesize that rivaroxaban will reduce the occurrence of clinically overt stroke, systemic embolism, and covert stroke when compared with ASA alone.

Oral anticoagulation for stroke prevention amongst atrial fibrillation patients with valvular heart disease: an update.

PURPOSE OF REVIEW: The majority of evidence on the safety and efficacy of oral anticoagulation for stroke prevention amongst patients with atrial fibrillation is derived from those without significant valvular heart disease. This article will review current knowledge, areas of uncertainty and controversy, and ongoing research on oral anticoagulation for stroke prevention amongst patients with valvular heart disease. RECENT FINDINGS: The rates of stroke, systemic embolism, and major bleeding were similar for patients with and without significant native valvular disease when treated with direct oral anticoagulants (DOACs) or vitamin K antagonists. There are very limited prospective data on the safety and efficacy of DOAC use for patients with bioprosthetic valves or rheumatic mitral stenosis. SUMMARY: Atrial fibrillation patients with concomitant valvulopathies constitute a group with high thromboembolic risk and should be treated with oral anticoagulation. There is good supportive evidence that DOAC is well tolerated and effective in preventing thromboembolism amongst patients with native valvular disease. Further research is underway to better define the risks and benefits of DOAC use among patients with bioprosthetic valves or rheumatic mitral stenosis in preventing thromboembolic events. Until then, vitamin K antagonists remain the oral anticoagulant of choice for these patient subsets.

Real-world outcomes, complications, and cost of catheter-based ablation for atrial fibrillation: an update.

PURPOSE OF REVIEW: Catheter-based ablation for atrial fibrillation is a useful and effective form of rhythm-control therapy for symptomatic patients. This article reviews the 'real-world' experience on the outcomes, complications, and costs of atrial fibrillation ablation. RECENT FINDINGS: Currently, real-world outcomes of atrial fibrillation ablation are derived from retrospective analysis of administrative databases or prospective registries from selected centers and patients. The rate of atrial fibrillation recurrence was reported to be as high as 60% and the rate of repeat ablation ranged from ≈10 to 18% within 1 year after ablation. All-cause hospitalizations after atrial fibrillation ablation were frequent, at up to ≈30% within 1 year and with up to half of them related to atrial fibrillation recurrence or repeat procedures. Rates of periprocedural complications were relatively low (≈3%). Female sex was associated with higher risk of complications such as bleeding, vascular injury, and tamponade. Markov models examining the cost-effectiveness of ablation yielded favorable results when success rates of more than 70% were assumed with long time horizons (>5 years). SUMMARY: The real-world outcomes of atrial fibrillation ablation are sobering. Confirmation of these findings with prospective, population-based, minimally biased studies is needed. There is a critical need to delineate the downstream economic impact of atrial fibrillation ablation on society to justify its continued delivery and growth.

Management of postoperative atrial fibrillation after cardiac surgery.

PURPOSE OF REVIEW: Postoperative atrial fibrillation (POAF) occurs commonly after cardiac surgery and is associated with a number of adverse outcomes. This article will review the available evidence on the prevention and treatment of atrial fibrillation after cardiac surgery. Using this knowledge, we propose a conceptual framework on the management of patients with POAF during various phases after cardiac surgery. RECENT FINDINGS: Perioperative ß-blockade is the cornerstone in preventing POAF after cardiac surgery. Results from randomized trials do not support routine use of colchicine or corticosteroids to prevent POAF. There is no study examining the impact of rate versus rhythm control on 'hard' clinical outcomes such as mortality or stroke in the cardiac surgical population. Furthermore, there is a paucity of research on the optimal timing and choice of oral anticoagulation among POAF cardiac surgical patients who are at risk for stroke. SUMMARY: In spite of the plethora of therapies available to treat and prevent POAF in the cardiac surgical population, there is little data to address whether they can improve key clinical outcomes such as death or stroke. Guideline recommendations on rate/rhythm control and oral anticoagulation for stroke prevention in the cardiac surgical population are largely extrapolated from studies of nonsurgical atrial fibrillation patients. Further research is needed to address these key atrial fibrillation management issues specific to the cardiac surgical population.

Long-term oral anticoagulation for patients after successful catheter ablation of atrial fibrillation: is it necessary?

PURPOSE OF REVIEW: Catheter ablation for atrial fibrillation is an effective rhythm-control therapy for selected patients. Currently, it is unknown whether maintenance of sinus rhythm after atrial fibrillation ablation can reduce one's stroke risk. If so, this may potentially obviate the need to treat patients with long-term oral anticoagulation (OAC). This article reviews the available evidence and areas of uncertainty pertaining to this question. RECENT FINDINGS: To date, no randomized trial data exist on this topic. Analyses from health administrative databases and observational registries suggested that atrial fibrillation patients who underwent catheter ablation had lower risk of stroke when compared with those who did not. Among patients who maintained sinus rhythm after ablation, low rates of stroke (<0.7% per year) were observed even after discontinuation of OAC therapy. These findings raise the possibility that successful catheter ablation may lower one's stroke risk to a point at which long-term OAC therapy is not obligatory. SUMMARY: Whether successful atrial fibrillation ablation reduces one's stroke risk is unknown. Low stroke risks were reported by observational studies in patients who maintained sinus rhythm after ablation despite OAC cessation. High-quality, randomized trial data are needed to provide clarity on this key unanswered question.

Bipolar ablation for deep intra-myocardial circuits: human ex vivo development and in vivo experience.

AIMS: Current conventional ablation strategies for ventricular tachycardia (VT) aim to interrupt reentrant circuits by creating ablation lesions. However, the critical components of reentrant VT circuits may be located at deep intramural sites. We hypothesized that bipolar ablations would create deeper lesions than unipolar ablation in human hearts. METHODS AND RESULTS: Ablation was performed on nine explanted human hearts at the time of transplantation. Following explant, the hearts were perfused by using a Langendorff perfusion setup. For bipolar ablation, the endocardial catheter was connected to the generator as the active electrode and the epicardial catheter as the return electrode. Unipolar ablation was performed at 50 W with irrigation of 25 mL/min, with temperature limit of 50°C. Bipolar ablation was performed with the same settings. Subsequently, in a patient with an incessant septal VT, catheters were positioned on the septum from both the ventricles and radiofrequency was delivered with 40 W. In the explanted hearts, there were a total of nine unipolar ablations and four bipolar ablations. The lesion depth was greater with bipolar ablation, 14.8 vs. 6.1 mm (P < 0.01), but the width was not different (9.8 vs. 7.8 mm). All bipolar lesions achieved transmurality in contrast to the unipolar ablations. In the patient with a septal focus, bipolar ablation resulted in termination of VT with no inducible VTs. CONCLUSION: By using a bipolar ablation technique, we have demonstrated the creation of significantly deeper lesions without increasing the lesion width, compared with standard ablation. Further clinical trials are warranted to detail the risks of this technique.

Canadian Heart Rhythm Society and Canadian Association of Radiologists consensus statement on magnetic resonance imaging with cardiac implantable electronic devices.

Magnetic resonance imaging (MRI) has historically been considered contraindicated for individuals with cardiac implantable electronic devices (CIEDs) such as pacemakers and implantable defibrillators. Magnetic resonance scanners produce magnetic fields that can interact negatively with the metallic components of CIEDs. However, as CIED technology has advanced, newer MRI conditional devices have been developed that are now in clinical use and these systems have had demonstrated safety in the MRI environment. Despite the supportive data of such CIED systems, physicians remain reluctant to perform MRI scanning of conditional devices. This joint statement by the Canadian Heart Rhythm Society and the Canadian Association of Radiologists describes a collaborative process by which CIED specialists and clinics can work with radiology departments and specialists to safely perform MRI in patients with MRI conditional CIED systems. The steps required for patient and scanning preparation and the roles and responsibilities of the CIED and radiology departments are outlined. We also briefly outline the risks and a process by which patients with nonconditional CIEDs might also receive MRI in highly specialized centres. This document supports MRI in patients with MRI conditional CIEDs and offers recommendations on how this can be implemented safely and effectively.

Sudden cardiac death due to ventricular arrhythmia in diabetes mellitus: A bench to bedside review.

Diabetes mellitus (DM) confers an increased risk of sudden cardiac death (SCD) independent of its associated cardiovascular comorbidities. DM induces adverse structural, electrophysiologic, and autonomic cardiac remodeling that can increase one's risk of ventricular arrhythmias and SCD. Although glycemic control and prevention of microvascular and macrovascular complications are cornerstones in the management of DM, they are not adequate for the prevention of SCD. In this narrative review, we describe the contribution of DM to the pathophysiologic mechanism of SCD beyond its role in atherosclerotic cardiovascular disease and heart failure. On the basis of this pathophysiologic framework, we outline potential preventive and therapeutic strategies to mitigate the risk of SCD in this population of high-risk patients.

P-Wave Duration/Amplitude Ratio Quantifies Atrial Low-Voltage Area and Predicts Atrial Arrhythmia Recurrence After Pulmonary Vein Isolation.

BACKGROUND: Atrial low-voltage areas (LVAs) in patients with atrial fibrillation increase the risk of atrial arrhythmia (AA) recurrence after pulmonary vein isolation (PVI). Contemporary LVA prediction scores (DR-FLASH, APPLE) do not include P-wave metrics. We aimed to evaluate the utility of P-wave duration/amplitude ratio (PWR) in quantifying LVA and predicting AA recurrence after PVI. METHODS: In 65 patients undergoing first-time PVI, 12-lead ECGs were recorded during sinus rhythm. PWR was calculated as the ratio between the longest P-wave duration and P-wave amplitude in lead I. High-resolution biatrial voltage maps were collected and LVAs included bipolar electrogram amplitudes < 0.5 mV or < 1.0 mV. An LVA quantification model was created with the use of clinical variables and PWR, and then validated in a separate cohort of 24 patients. Seventy-eight patients were followed for 12 months to evaluate AA recurrence. RESULTS: PWR strongly correlated with left atrial (LA) (< 0.5 mV: r = 0.60; < 1.0 mV: r = 0.68; P < 0.001) and biatrial LVA (< 0.5 mV: r = 0.63; < 1.0 mV: r = 0.70; P < 0.001). Addition of PWR to clinical variables improved model quantification of LA LVA at the < 0.5 mV (adjusted R2 = 0.59 to 0.68) and < 1.0 mV (adjusted R2 = 0.59 to 0.74) cutoffs. In the validation cohort, PWR model-predicted LVA correlated strongly with measured LVA (< 0.5 mV: r = 0.78; < 1.0 mV: r = 0.81; P < 0.001). PWR model was superior to DR-FLASH (area under the receiver operating characteristic curve [AUC] 0.90 vs 0.78; P = 0.030) and APPLE (AUC 0.90 vs 0.67; P = 0.003) at detecting LA LVA and similar at predicting AA recurrence after PVI (AUC 0.67 vs 0.65 and 0.60). CONCLUSION: Our novel PWR model accurately quantifies LVA and predicts AA recurrence after PVI. PWR model-predicted LVA may help guide patient selection for PVI.

Combined Minimally Invasive Surgical and Percutaneous Catheter Ablation of Atrial Fibrillation: JACC Review Topic of the Week.

Hybrid ablation is a novel therapy in the invasive management of patients with atrial fibrillation (AF) which combines minimally invasive surgical and percutaneous catheter-based techniques. The evidence is mainly based on observational studies from experienced centers, with success rates of approximately 70% and risks that are 2.0-fold to 3.6-fold higher than catheter-based ablation. Hybrid ablation is offered typically to patients with persistent or longstanding persistent AF which, by design, requires 2 procedures (epicardial surgical and endocardial catheter-based ablation). One randomized trial demonstrated that hybrid ablation was more effective than catheter-based ablation, but with higher complication rates. The incidence of the most serious complications has decreased in contemporary studies of hybrid ablation. At present, hybrid ablation should be performed by experienced centers on selected patients with persistent or longstanding persistent AF. Additional randomized trials are needed to define the risks, benefits, and cost effectiveness of hybrid ablation to identify its most appropriate application in clinical practice.