Associations between 3D-based Left Atrial Volumetric and Blood Flow Parameters in a Single-Site Cohort of the Multi-Ethnic Study of Atherosclerosis

Purpose To investigate associations between left atrial volume (LAV) and function with impaired three-dimensional hemodynamics from four-dimensional flow MRI. Materials and Methods A subcohort of participants from the Multi-Ethnic Study of Atherosclerosis from Northwestern University underwent prospective 1.5-T cardiac MRI including whole-heart four-dimensional flow and short-axis cine imaging between 2019 and 2020. Four-dimensional flow MRI analysis included manual three-dimensional segmentations of the LA and LA appendage (LAA), which were used to quantify LA and LAA peak velocity and blood stasis (% voxels < 0.1 m/sec). Short-axis cine data were used to delineate LA contours on all cardiac time points, and the resulting three-dimensional-based LAVs were extracted for calculation of LA emptying fractions (LAEFtotal, LAEFactive, LAEFpassive). Stepwise multivariable linear models were calculated for each flow parameter (LA stasis, LA peak velocity, LAA stasis, LAA peak velocity) to determine associations with LAV and LAEF. Results This study included 158 participants (mean age, 73 years ± 7 [SD]; 83 [52.5%] female and 75 [47.4%] male participants). In multivariable models, a 1-unit increase of LAEFtotal was associated with decreased LA stasis (β coefficient, -0.47%; P < .001), while increased LAEFactive was associated with increased LA peak velocity (β coefficient, 0.21 cm/sec; P < .001). Furthermore, increased minimum LAV indexed was most associated with impaired LAA flow (higher LAA stasis [β coefficient, 0.65%; P < .001] and lower LAA peak velocity [β coefficient, -0.35 cm/sec; P < .001]). Conclusion Higher minimum LAV and reduced LA function were associated with impaired flow characteristics in the LA and LAA. LAV assessment might therefore be a surrogate measure for LA and LAA flow abnormalities. Keywords: Atherosclerosis, Left Atrial Volume, Left Atrial Blood Flow, 4D Flow MRI Supplemental material is available for this article. © RSNA, 2024.

Use of Atrial Fibrillation Electrograms and T1/T2 Magnetic Resonance Imaging to Define the Progressive Nature of Molecular and Structural Remodeling: A New Paradigm Underlying the Emergence of Persistent Atrial Fibrillation

BACKGROUND

The temporal progression states of the molecular and structural substrate in atrial fibrillation (AF) are not well understood. We hypothesized that these can be detected by AF electrograms and magnetic resonance imaging parametric mapping.

METHODS AND RESULTS

AF was induced in 43 dogs (25-35 kg, ≥1 year) by rapid atrial pacing (RAP) (3-33 weeks, 600 beats/min), and 4 controls were used. We performed high-resolution epicardial mapping (UnEmap, 6 atrial regions, both atria, 130 electrodes, distance 2.5 mm) and analyzed electrogram cycle length, dominant frequency, organization index, and peak-to-peak bipolar voltage. Implantable telemetry recordings were used to quantify parasympathetic nerve activity over RAP time. Magnetic resonance imaging native T1, postcontrast T1, T2 mapping, and extracellular volume fraction were assessed (1.5T, Siemens) at baseline and AF. In explanted atrial tissue, DNA oxidative damage (8-hydroxy-2'-deoxyguanosine staining) and percentage of fibrofatty tissue were quantified. Cycle length and organization index decreased (R=0.5, P<0.05; and R=0.5, P<0.05; respectively), and dominant frequency increased (R=0.3, P n.s.) until 80 days of RAP but not thereafter. In contrast, voltage continued to decrease throughout the duration of RAP (R=0.6, P<0.05). Parasympathetic nerve activity increased following RAP and plateaued at 80 days. Magnetic resonance imaging native T1 and T2 times increased with RAP days (R=0.5, P<0.05; R=0.6, P<0.05) in the posterior left atrium throughout RAP. Increased RAP days correlated with increasing 8-hydroxy-2'-deoxyguanosine levels and with fibrosis percentage (R=0.5, P<0.05 for both).

CONCLUSIONS

A combination of AF electrogram characteristics and T1/T2 magnetic resonance imaging can detect early-stage AF remodeling (autonomic remodeling, oxidative stress) and advanced AF remodeling due to oxidative stress and fibrosis.

Comparative effectiveness and healthcare utilization for ambulatory cardiac monitoring strategies in Medicare beneficiaries

BACKGROUND

Objective data comparing the diagnostic performance of different ambulatory cardiac monitors (ACMs) are lacking.

OBJECTIVES

To assess variation in monitoring strategy, clinical outcomes and healthcare utilization in patients undergoing ambulatory monitoring without a pre-existing arrhythmia diagnosis.

METHODS

Using the full sample (100%) of Medicare claims data, we performed a retrospective cohort study of diagnostic-naïve patients who received first-time ACM in 2017 to 2018 and evaluated arrhythmia encounter diagnosis at 3-months, repeat ACM testing at 6 months, all-cause 90-day emergency department (ED) and inpatient utilization, and cost of different strategies: Holter; long-term continuous monitor (LTCM); non-continuous, event-based external ambulatory event monitor (AEM); and mobile cardiac telemetry (MCT). We secondarily performed a device-specific analysis by manufacturer, identified from unique claim modifier codes.

RESULTS

ACMs were used in 287,789 patients (AEM = 10.3%; Holter = 53.8%; LTCM = 13.3%; MCT = 22.5%). Device-specific analysis showed that compared to Holter, AEM, MCT, or other LTCM manufacturers, a specific LTCM (ZioⓇ XT 14-day patch, iRhythm Technologies, San Francisco, CA) had the highest adjusted odds of diagnosis and lowest adjusted odds of ACM retesting. Findings were consistent for specific arrhythmia diagnoses of ventricular tachycardia, atrioventricular block, and paroxysmal atrial fibrillation. As a category, LTCM was associated with the lowest 1-year incremental health care expenditures (mean Δ$10,159), followed by Holter ($10,755), AEM ($11,462), and MCT ($12,532).

CONCLUSIONS

There was large variation in diagnostic monitoring strategy. A specific LTCM was associated with the highest adjusted odds of a new arrhythmia diagnosis and lowest adjusted odds of repeat ACM testing. LTCM as a category had the lowest incremental acute care utilization. Different monitoring strategies may produce different results with respect to diagnosis and care.

Promises and Perils of Consumer Mobile Technologies in Cardiovascular Care: JACC Scientific Statement

Direct-to-consumer (D2C) wearables are becoming increasingly popular in cardiovascular health management because of their affordability and capability to capture diverse health data. Wearables may enable continuous health care provider-patient partnerships and reduce the volume of episodic clinic-based care (thereby reducing health care costs). However, challenges arise from the unregulated use of these devices, including questionable data reliability, potential misinterpretation of information, unintended psychological impacts, and an influx of clinically nonactionable data that may overburden the health care system. Further, these technologies could exacerbate, rather than mitigate, health disparities. Experience with wearables in atrial fibrillation underscores these challenges. The prevalent use of D2C wearables necessitates a collaborative approach among stakeholders to ensure effective integration into cardiovascular care. Wearables are heralding innovative disease screening, diagnosis, and management paradigms, expanding therapeutic avenues, and anchoring personalized medicine.

Ultra-rapid, Free-breathing, Real-time Cardiac Cine MRI Using GRASP Amplified with View Sharing and KWIC Filtering

Purpose To achieve ultra-high temporal resolution (approximately 20 msec) in free-breathing, real-time cardiac cine MRI using golden-angle radial sparse parallel (GRASP) reconstruction amplified with view sharing (VS) and k-space-weighted image contrast (KWIC) filtering. Materials and Methods Fourteen pediatric patients with congenital heart disease (mean age [SD], 9 years ± 2; 13 male) and 10 adult patients with arrhythmia (mean age, 62 years ± 8; nine male) who underwent both standard breath-hold cine and free-breathing real-time cine using GRASP were retrospectively identified. To achieve high temporal resolution, each time frame was reconstructed using six radial spokes, corresponding to acceleration factors ranging from 24 to 32. To compensate for loss in spatial resolution resulting from over-regularization in GRASP, VS and KWIC filtering were incorporated. The blur metric, visual image quality scores, and biventricular parameters were compared between clinical and real-time cine images. Results In pediatric patients, the incorporation of VS and KWIC into GRASP (ie, GRASP + VS + KWIC) produced significantly (P < .05) sharper x-y-t (blur metric: 0.36 ± 0.03, 0.41 ± 0.03, 0.48 ± 0.03, respectively) and x-y-f (blur metric: 0.28 ± 0.02, 0.31 ± 0.03, 0.37 ± 0.03, respectively) component images compared with GRASP + VS and conventional GRASP. Only the noise score differed significantly between GRASP + VS + KWIC and clinical cine; all visual scores were above the clinically acceptable (3.0) cutoff point. Biventricular volumetric parameters strongly correlated (R2 > 0.85) between clinical and real-time cine images reconstructed with GRASP + VS + KWIC and were in good agreement (relative error < 6% for all parameters). In adult patients, the visual scores of all categories were significantly lower (P < .05) for clinical cine compared with real-time cine with GRASP + VS + KWIC, except for noise (P = .08). Conclusion Incorporating VS and KWIC filtering into GRASP reconstruction enables ultra-high temporal resolution (approximately 20 msec) without significant loss in spatial resolution. Keywords: Cine, View Sharing, k-Space-weighted Image Contrast Filtering, Radial k-Space, Pediatrics, Arrhythmia, GRASP, Compressed Sensing, Real-Time, Free-Breathing Supplemental material is available for this article. © RSNA, 2024.

Robust and fast stochastic 4D flow vector-field signature technique for quantifying composite flow dynamics from 4D flow MRI: Application to left atrial flow in atrial fibrillation

4D flow MRI is an emerging imaging modality that maps voxel-wise blood flow information as velocity vector fields that is acquired in 7-dimensional image volumes (3 spatial dimensions + 3 velocity directions + time). Blood flow in the cardiovascular system is often complex and composite involving multiple flow dynamics and patterns (e.g., vortex flow, jets, stagnating flow) that occur and interact simultaneously. The spectrum of such complex flow dynamics is embedded in the velocity vector field dynamics derived from 4D Flow MRI. However, current flow metrics cannot fully measure high-dimensional vector-field data and embedded complex composite flow data. Instead, these methods need to break down the vector-field data into secondary scalar fields of individual flow components using fluid dynamics operators. These methods are gradient-based and sensitive to data uncertainties, and only focus on individual flow components of the overall composite flow, therefore potentially underestimating the severity of overall flow changes associated with cardiovascular diseases. To address these limitations, in MICCAI 2021, we introduced a novel comprehensive stochastic 4D Flow vector-field signature technique that works directly on the entire spatiotemporal velocity vector field. This technique uses efficient stochastic gradient-free interrogation of multi-million flow vector-pairs per patient to derive the patient's unique flow profile of the complex composite flow alterations and in real-time processing. The signature technique's probabilistic gradient-free formulation should allow for highly robust quantification despite inherent errors in 4D flow MRI acquisitions. Here, we extend the application of the 4D flow vector-field signature technique to the left atrium to analyze complex composite flow changes in patients with atrial fibrillation. In 128 subjects, we performed extensive sensitivity testing and determined that the vector-field signature technique is highly robust to typical sources of data uncertainties in 4D flow MRI: degradation in spatiotemporal resolution, added Gaussian noise, and segmentation errors. We demonstrate the excellent generalizability of the stochastic convergence from the aorta to the left atrium and between different 4D Flow MRI acquisition protocols. We compare the robustness of our technique to existing advanced flow quantification metrics of kinetic energy, vorticity, and energy loss demonstrating a superior performance of up-to 14-fold. Our results show the potential diagnostic and clinical utility of our signature technique in identifying distinctly altered composite flow signatures in atrial fibrillation patients independent of existing flow metrics.

Assessment of Beat-To-Beat Variability in Left Atrial Hemodynamics Using Real Time Phase Contrast MRI in Patients With Atrial Fibrillation

BACKGROUND

Hemodynamic assessment of left atrial (LA) flow using phase contrast MRI provides insight into thromboembolic risk in atrial fibrillation (AF). However, conventional flow imaging techniques are averaged over many heartbeats.

PURPOSE

To evaluate beat-to-beat variability and LA hemodynamics in patients with AF using real time phase contrast (RTPC) MRI.

STUDY TYPE

Prospective.

SUBJECTS

Thirty-five patients with history of AF (68 ± 10 years, nine female), 10 healthy controls (57 ± 19 years, four female).

FIELD STRENGTH/SEQUENCE

5T, 2D RTPC with through-plane velocity-encoded gradient echo sequence and 4D flow MRI with three-directional velocity-encoded gradient echo sequence.

ASSESSMENT

RTPC was continuously acquired for a mid-LA slice in all subjects. 4D flow data were interpolated at the RTPC location and normally projected for comparison with RTPC. RR intervals extracted from RTPC were used to calculate heart rate variability (HRV = interquartile range over median × 100%). Patients were classified into low (<9.7%) and high (>9.7%) HRV groups. LA peak/mean velocity and stasis (%velocities < 5.8 cm/sec) were calculated from segmented 2D images. Variability in RTPC flow metrics was quantified by coefficient of variation (CV) over all cycles.

STATISTICAL TESTS

Pearson's correlation coefficient (r), Bland-Altman analysis, Kruskal-Wallis test. A P value < 0.05 was considered statistically significant.

RESULTS

RTPC and 4D flow measurements were strongly/significantly correlated for all hemodynamic parameters (R2  = 0.75-0.83) in controls. Twenty-four patients had low HRV (mean = 4 ± 2%) and 11 patients had high HRV (27 ± 9%). In patients, increased HRV was significantly correlated with CV of peak velocity (r = 0.67), mean velocity (r = 0.51), and stasis (r = 0.41). A stepwise decrease in peak/mean velocity and increase in stasis was observed when comparing controls vs. low HRV vs. high HRV groups. Mean velocity and stasis differences were significant for control vs. high HRV groups.

CONCLUSIONS

RTPC may be suitable for assessing the impact of HRV on hemodynamics and provide insight for AF management in highly arrhythmic patients.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 2.

The impact of catheter ablation in patient's heart failure and atrial fibrillation: a meta-analysis of randomized clinical trials

BACKGROUND

Recent trial data suggest a benefit to catheter ablation (CA) compared to medical therapy for atrial fibrillation (AF) in patients with heart failure (HF). Nevertheless, because of mixed trial evidence, contemporary guidelines give it a class 2 recommendation. Accordingly, we sought to assess the currently available evidence for CA in HF with AF.

METHODS

Electronic databases were searched to identify randomized clinical trials (RCTs) comparing CA to medical therapy in patients with AF and HF. Study data was pooled using fixed and random effects, and the number needed to treat (NNT) was calculated to gauge absolute risk differences. Heterogeneity was quantified using I2. Our primary outcome was all-cause mortality.

RESULTS

Nine trials (CA 1075 patients; medical therapy 1083 patients) were included. Ablation reduced the relative risk of all-cause mortality by 31.5% (95% CI 13.7 to 45.6%; NNT = 23), cardiovascular mortality by 39.3% (95% CI 10.9 to 58.7%; NNT = 31), cardiovascular hospitalization by 29.1% (95% CI 9.4 to 44.6%; NNT = 9), and heart failure hospitalization by 28.5% (95% CI 6.5 to 45.4%; NNT = 22). Improvements in quality of life were observed with CA using the Minnesota Living with Heart Failure Questionnaire (mean difference - 5.26; 95% CI - 2.73 to - 7.78) and the Atrial Fibrillation Effect on Quality of Life (mean difference 5.36; 95% CI 2.72 to 8.00).

CONCLUSION

Compared to medical therapy, CA for AF in patients with HF reduces all-cause mortality, cardiovascular mortality, cardiovascular hospitalizations, and heart failure hospitalizations, and may improve quality of life.

Does early detection of atrial fibrillation reduce the risk of thromboembolic events? Rationale and design of the Heartline study

BACKGROUND

The impact of using direct-to-consumer wearable devices as a means to timely detect atrial fibrillation (AF) and to improve clinical outcomes is unknown.

METHODS

Heartline is a pragmatic, randomized, and decentralized application-based trial of US participants aged ≥65 years. Two randomized cohorts include adults with possession of an iPhone and without a history of AF and those with a diagnosis of AF taking a direct oral anticoagulant (DOAC) for ≥30 days. Participants within each cohort are randomized (3:1) to either a core digital engagement program (CDEP) via iPhone application (Heartline application) and an Apple Watch (Apple Watch Group) or CDEP alone (iPhone-only Group). The Apple Watch Group has the watch irregular rhythm notification (IRN) feature enabled and access to the ECG application on the Apple Watch. If an IRN notification is issued for suspected AF then the study application instructs participants in the Apple Watch Group to seek medical care. All participants were "watch-naïve" at time of enrollment and have an option to either buy or loan an Apple Watch as part of this study. The primary end point is time from randomization to clinical diagnosis of AF, with confirmation by health care claims. Key secondary endpoint are claims-based incidence of a 6-component composite cardiovascular/systemic embolism/mortality event, DOAC medication use and adherence, costs/health resource utilization, and frequency of hospitalizations for bleeding. All study assessments, including patient-reported outcomes, are conducted through the study application. The target study enrollment is approximately 28,000 participants in total; at time of manuscript submission, a total of 26,485 participants have been enrolled into the study.

CONCLUSION

The Heartline Study will assess if an Apple Watch with the IRN and ECG application, along with application-facilitated digital health engagement modules, improves time to AF diagnosis and cardiovascular outcomes in a real-world environment.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04276441.

Monitoring for atrial fibrillation prior to patent foramen ovale closure after cryptogenic stroke

BACKGROUND

Patients who had a cryptogenic stroke (CS) suspected to be causally related to a patent foramen ovale (PFO) are candidates for percutaneous PFO closure. In such patients, it is important to screen for atrial fibrillation (AF). Limited guidance is available regarding AF monitoring strategies in CS patients with PFO addressing optimal monitoring technology and duration.

AIM

To provide a narrative review of cardiac rhythm monitoring in CS patients considered for PFO closure, including current practices, stroke recurrences after CS, findings from monitoring studies in CS patients, and predictors for AF detection published in the literature. To propose a personalized strategy for cardiac monitoring in CS patients, accounting for aspects predicting AF detection.

SUMMARY OF REVIEW

AF detection in CS patients is predicted by age, left atrial enlargement, prolonged PR interval, frequent premature atrial contractions, interatrial conduction block, diabetes, prior brain infarctions, leukoaraiosis, elevated B-type natriuretic peptide (BNP)/N-terminal pro B-type natriuretic peptide (NT-proBNP) levels, and a family history of AF, as well as composed scores (e.g. CHA₂DS₂-VASc, atrial fibrillation in embolic stroke of undetermined source (AF-ESUS)). The causal role of the PFO may be accounted for by the risk of paradoxical embolism (RoPE) score and/or the PFO-Associated Stroke Causal Likelihood (PASCAL) classification.

CONCLUSION

A personalized approach to AF detection in CS patients is proposed, accounting for the likelihood of AF detection and aimed at obtaining sufficient confidence regarding the absence of AF in patients considered for PFO closure. In addition, the impact of high-risk PFO features on the monitoring strategy is discussed.

Implementation of an intravenous sotalol initiation protocol: Implications for feasibility, safety, and length of stay

INTRODUCTION

Oral sotalol initiation requires a multiple-day, inpatient admission to monitor for QT prolongation during loading. A 1-day intravenous (IV) sotalol loading protocol was approved by the United States Food and Drug Administration in March 2020, but limited data on clinical use and administration currently exists. This study describes implementation of an IV sotalol protocol within an integrated health system, provides initial efficacy and safety outcomes, and examines length of stay (LOS) compared with oral sotalol initiation.

METHODS

IV sotalol was administered according to a prespecified initiation protocol to adult patients with refractory atrial or ventricular arrhythmias. Baseline characteristics, safety and feasibility outcomes, and LOS were compared with patients receiving oral sotalol over a similar time period.

RESULTS

From January 2021 to June 2022, a total of 29 patients (average age 66.0 ± 8.6 years, 27.6% women) underwent IV sotalol load and 20 patients (average age 60.4 ± 13.9 years, 65.0% women) underwent oral sotalol load. The load was successfully completed in 22/29 (75.9%) patients receiving IV sotalol and 20/20 (100%) of patients receiving oral sotalol, although 7/20 of the oral sotalol patients (35.0%) required dose reduction. Adverse events interrupting IV sotalol infusion included bradycardia (seven patients, 24.1%) and QT prolongation (three patients, 10.3%). No patients receiving IV or oral sotalol developed sustained ventricular arrhythmias before discharge. LOS for patients completing IV load was 2.6 days shorter (mean 1.0 vs. 3.6, p < .001) compared with LOS with oral load.

CONCLUSION

IV sotalol loading has a safety profile that is similar to oral sotalol. It significantly shortens hospital LOS, potentially leading to large cost savings.

Quantification of left atrial function by the area-length method overestimates left atrial emptying fraction

PURPOSE

The biplane area-length method is commonly used in cardiac magnetic resonance (CMR) to assess left atrial (LA) volume (LAV) and function. Associations between left atrial emptying fraction (LAEF) and clinical outcomes have been reported. However, only limited data are available on the calculation of LAEF using the biplane method compared to 3D assessment. This study aimed to compare volumetric and functional LA parameters obtained from the biplane method with 3D assessment in a large, multiethnic cohort.

METHOD

158 participants of MESA (Multi-Ethnic Study of Atherosclerosis) underwent CMR that included standard two- and four-chamber steady-state free precession (SSFP) cine imaging for the biplane method. For 3D-based assessment, short-axis SSFP cine series covering the entire LA were obtained, followed by manual delineation of LA contours to create a time-resolved 3D LAV dataset. Paired t-tests and Bland-Altman plots were used to analyze the data.

RESULTS

Standard volumetric assessment showed that LAVmin (bias: -8.35 mL, p < 0.001), LAVmax (bias: -9.38 mL, p < 0.001) and LAVpreA (bias: -10.27 mL, p < 0.001) were significantly smaller using the biplane method compared to 3D assessment. Additionally, the biplane method reported significantly higher LAEFtotal (bias: 7.22 %, p < 0.001), LAEFactive (bias: 6.08 %, p < 0.001), and LAEFpassive (bias: 4.51 %, p < 0.001) with wide limits of agreement.

CONCLUSIONS

LA volumes were underestimated using the biplane method compared to 3D assessment, while LAEF parameters were overestimated. These findings demonstrate a lack of precision using the biplane method for LAEF assessment. Our results support the usage of 3D assessment in specific settings when LA volumetric and functional parameters are in focus.

Comparison of data quality and monitoring completion rates between clinic and self-applied ECG patches

BACKGROUND

Since the onset of the coronavirus disease 2019 (COVID-19) pandemic, direct-to-patient, self-applied ECG patch use has substantially increased. There are limited data comparing clinic with self-applied electrocardiogram (ECG) patches.

OBJECTIVE

The purpose of this study was to compare rates of ECG patch return, percentages of time patches yielded analyzable data (analyzable time), and percentages of prescribed time ECG patches were worn between clinic and self-applied ECG patches before and during COVID-19.

METHODS

A retrospective analysis of patients prescribed an ECG patch during "pre-COVID" (March 1, 2019, through March 1, 2020) and "COVID" (April 4, 2020, through April 1, 2021) years was performed. ECG patch return rates, mean percentages of analyzable time, and mean percentages of prescribed wear time were compared between clinic and self-applied groups.

RESULTS

Among the 29,093 ECG patch prescriptions (19% COVID self-applied), the COVID self-applied group had a lower return rate (90.8%) than did both clinic-applied groups (COVID: 97.1%; pre-COVID: 98.1%; P < .001). Among the 28,048 ECG patches (17.5% self-applied) returned for analysis, the COVID self-applied group demonstrated a lower mean percentage of analyzable time (95.9% ± 8.2%) than did both clinic-applied groups (COVID: 96.6% ± 6.6%; pre-COVID 96.6% ± 7.4%; P < .001). There were no differences in the mean percentage of prescribed wear time between groups (pre-COVID clinic-applied: 96.7% ± 34.3%; COVID clinic-applied: 97.4% ± 39.8%; COVID self-applied: 98.1% ± 52.1%; P = .09).

CONCLUSION

Self-applied ECG patches were returned at a lower rate and had a statistically lower percentage of analyzable time than clinic-applied patches. However, there were no differences between groups in mean percentages of prescribed wear time, and mean percentages of analyzable time were >95% in all groups.

Effects of catheter ablation of atrial fibrillation on the biomarker profile

BACKGROUND

Following catheter ablation for atrial fibrillation (AF), there are dynamic changes in the atrial myocardium associated with damage to and necrosis of atrial tissue and other procedure related changes in rhythm and anticoagulation. Early time-dependent changes in biomarkers of necrosis, inflammation, and coagulation have been reported. This study examines mid-term (4-8 weeks post-ablation) changes in biomarkers and explores their ability to predict AF recurrence at one-year.

METHODS

Twenty-seven patients (mean age 65.4 ± 9.7 years, 30% female) undergoing catheter ablation for AF had peripheral venous blood samples obtained at the time of ablation and 4-8 weeks later. All samples were processed to obtain plasma which was frozen for subsequent analysis. Coagulation studies were performed at the Northwestern Special Hemostasis Laboratory: VWF, ADAMTS13, PAI-1, D-dimer, and TAT complexes. A commercial lab analyzed samples for CRP, cystatin C, fibrinogen, galectin, IL-6, MMP-2, myoglobin, NT-proBNP, PAI-1, TIMP-1, TIMP-2, TPA, and VWF.

RESULTS

Significant changes were noted with higher levels of ADAMTS13 (p < 0.0001), fibrinogen (p = 0.004), MMP-2 (p = 0.0002), TIMP-2 (p = 0.003), and TPA (p = 0.001) compared to lower levels of TAT (p < 0.0001) and NT-proBNP (p = 0.0001) at follow up post-ablation. One year after ablation, AF had recurred in 11/26 (42%) of patients. None of the biomarker changes predicted the 1-year outcome, and there was no significant association with the use of warfarin versus rivaroxaban.

CONCLUSION

In patients undergoing catheter ablation for AF, there were significant changes in pre- vs post-ablation levels of multiple biomarkers. However, these changes were not associated with 1-year outcome of AF recurrence.

Predictors of Atrial Fibrillation in Patients With Stroke Attributed to Large- or Small-Vessel Disease: A Prespecified Secondary Analysis of the STROKE AF Randomized Clinical Trial

Importance

The Stroke of Known Cause and Underlying Atrial Fibrillation (STROKE AF) trial found that approximately 1 in 8 patients with recent ischemic stroke attributed to large- or small-vessel disease had poststroke atrial fibrillation (AF) detected by an insertable cardiac monitor (ICM) at 12 months. Identifying predictors of AF could be useful when considering an ICM in routine poststroke clinical care.

Objective

To determine the association between commonly assessed risk factors and poststroke detection of new AF in the STROKE AF cohort monitored by ICM.

Design, Setting, and Participants

This was a prespecified analysis of a randomized (1:1) clinical trial that enrolled patients between April 1, 2016, and July 12, 2019, with primary follow-up through 2020 and mean (SD) duration of 11.0 (3.0) months. Eligible patients were selected from 33 clinical research sites in the US. Patients had an index stroke attributed to large- or small-vessel disease and were 60 years or older or aged 50 to 59 years with at least 1 additional stroke risk factor. A total of 496 patients were enrolled, and 492 were randomly assigned to study groups (3 did not meet inclusion criteria, and 1 withdrew consent). Patients in the ICM group had the index stroke within 10 days before insertion. Data were analyzed from October 8, 2021, to January 28, 2022.

Interventions

ICM monitoring vs site-specific usual care (short-duration external cardiac monitoring).

Main Outcomes and Measures

The ICM device automatically detects AF episodes 2 or more minutes in length; episodes were adjudicated by an expert committee. Cox regression multivariable modeling included all parameters identified in the univariate analysis having P values <.10. AF detection rates were calculated using Kaplan-Meier survival estimates.

Results

The analysis included the 242 participants randomly assigned to the ICM group in the STROKE AF study. Among 242 patients monitored with ICM, 27 developed AF (mean [SD] age, 66.6 [9.3] years; 144 men [60.0%]; 96 [40.0%] women). Two patients had missing baseline data and exited the study early. Univariate predictors of AF detection included age (per 1-year increments: hazard ratio [HR], 1.05; 95% CI, 1.01-1.09; P = .02), CHA2DS2-VASc score (per point: HR, 1.54; 95% CI, 1.15-2.06; P = .004), chronic obstructive pulmonary disease (HR, 2.49; 95% CI, 0.86-7.20; P = .09), congestive heart failure (CHF; with preserved or reduced ejection fraction: HR, 6.64; 95% CI, 2.29-19.24; P < .001), left atrial enlargement (LAE; HR, 3.63; 95% CI, 1.55-8.47; P = .003), QRS duration (HR, 1.02; 95% CI, 1.00-1.04; P = .04), and kidney dysfunction (HR, 3.58; 95% CI, 1.35-9.46; P = .01). In multivariable modeling (n = 197), only CHF (HR, 5.06; 95% CI, 1.45-17.64; P = .05) and LAE (HR, 3.32; 1.34-8.19; P = .009) remained significant predictors of AF. At 12 months, patients with CHF and/or LAE (40 of 142 patients) had an AF detection rate of 23.4% vs 5.0% for patients with neither (HR, 5.1; 95% CI, 2.0-12.8; P < .001).

Conclusions and Relevance

Among patients with ischemic stroke attributed to large- or small-vessel disease, CHF and LAE were associated with a significantly increased risk of poststroke AF detection. These patients may benefit most from the use of ICMs as part of a secondary stroke prevention strategy. However, the study was not powered for clinical predictors of AF, and therefore, other clinical characteristics may not have reached statistical significance.

Trial Registration

ClinicalTrials.gov Identifier: NCT02700945.

Development of Complementary Encounter and Patient Decision Aids for Shared Decision Making about Stroke Prevention in Atrial Fibrillation

Introduction

Decision aids (DAs) are helpful instruments used to support shared decision making (SDM). Patients with atrial fibrillation (AF) face complex decisions regarding stroke prevention strategies. While a few DAs have been made for AF stroke prevention, an encounter DA (EDA) and patient DA (PDA) have not been created to be used in conjunction with each other before.

Design

Using iterative user-centered design, we developed 2 DAs for anticoagulation choice and stroke prevention in AF. Prototypes were created, and we elicited feedback from patients and experts via observations of encounters, usability testing, and semistructured interviews.

Results

User testing was done with 33 experts (in AF and SDM) and 51 patients from 6 institutions. The EDA and PDA underwent 1 and 4 major iterations, respectively. Major differences between the DAs included AF pathophysiology and a preparation to meet with the clinician in the PDA as well as different language throughout. Content areas included personalized stroke risk, differences between anticoagulants, and risks of bleeding. Based on user feedback, developers 1) addressed feelings of isolation with AF, 2) improved navigation options, 3) modified content and flow for users new to AF and those experienced with AF, 4) updated stroke risk pictographs, and 5) added structure to the preparation for decision making in the PDA.

Limitations

These DAs focus only on anticoagulation for stroke prevention and are online, which may limit participation for those less comfortable with technology.

Conclusions

Designing complementary DAs for use in tandem or separately is a new method to support SDM between patients and clinicians. Extensive user testing is essential to creating high-quality tools that best meet the needs of those using them.

Highlights

First-time complementary encounter and patient decision aids have been designed to work together or separately.User feedback led to greater structure and different experiences for patients naïve or experienced with anticoagulants in patient decision aids.Online tools allow for easier dissemination, use in telehealth visits, and updating as new evidence comes out.

Stroke Prevention in Atrial Fibrillation

PURPOSE OF REVIEW

Atrial fibrillation is associated with a significant increase in stroke and systemic embolism. This review explores the areas of stroke prevention.

RECENT FINDINGS

In the last decade, NOAC has overtaken warfarin as the anticoagulant of choice for stroke prevention in AF. For patients unable to take anticoagulation, LAA closure has proven to be a valid option. The use of digital devices has led to widespread consumer-directed AF screening. It remains to be determined if all device detect AF pose the same amount of risk as recent studies have shown that short and infrequent episodes of AF may not benefit from anticoagulation. Stroke prevention is paramount in the management of AF. In this review we describe the risk factors contributing to stroke, recent advances in antithrombotic therapies, and the increasing role of digital health in guiding AF detection and stroke prevention.

Thirty-day readmission rate of same-day discharge protocol after left atrial appendage occlusion: A propensity score-matched analysis from the National Readmission Database

BACKGROUND

Given the reduction in periprocedural complication rates, same-day discharge (SDD) after percutaneous left atrial appendage closure (LAAC) could be beneficial. To date, little data exist comparing the standard overnight stay (ONS) vs SDD after LAAC.

OBJECTIVE

The purpose of this study was to investigate the safety and efficacy of SDD compared with ONS.

METHODS

A retrospective cohort study of LAAC procedures performed in the United States from 2015 to 2019 was conducted using the US Nationwide Readmission Database. The primary outcome was all-cause 30-day readmission after discharge in patients who underwent LAAC, and a secondary outcome was requiring total health care cost. A 1:1 propensity score matching was conducted for adjustment. Multivariate Cox proportional hazards regression was also performed to estimate the hazard ratio for all-cause readmission within 30 days of LAAC.

RESULTS

Of 48,953 patients (mean age 76.0 ± 7.9 years), 972 patients (1.99%) were discharged on the same day after LAAC (SDD group) and the remaining 47,981 patients stayed at least 1 night (ONS group). A propensity score-matched analysis generated 961 matched pairs in each group. The 30-day readmission rate after discharge was similar between the groups (SDD vs ONS: 8.5% vs 9.8%; P = .31; hazard ratio 1.13; 95% confidence interval 0.78-1.63; P = .53). The total required health care cost was significantly lower in the SDD group ($23,720 [$18,075-$29,416] vs $25,877 [$19,906-$32,748]; P < .01). Gastrointestinal bleeding was the major cause for readmission (SDD vs ONS: 14.7% vs 15.1%; P = .95), but stroke and pericardial effusion were rare.

CONCLUSION

In patients without procedure-related complications, SDD is a safe and cost-effective protocol.

Staged hybrid totally thoracoscopic maze and catheter ablation for atrial fibrillation

INTRODUCTION

Atrial fibrillation (AF) is a growing health problem and is associated with increased risk of stroke. The Cox-Maze surgical procedure has offered the highest success rate, but utilization of this technique is low due to procedure invasiveness and complexity. Advances in catheter ablation and minimally invasive surgical techniques offer new options for AF treatment.

METHODS

In this review, we describe current trends and outcomes of minimally invasive treatment of persistent and long-standing persistent AF.

RESULTS

Treatment of persistent and long-standing persistent AF can be successfully treated using a team approach combining cardiac surgery and electrophysiology procedures. With this approach, the 1-year freedom from AF off antiarrhythmic drugs was 85%.

DISCUSSION

There are a variety of techniques and approaches used around the world as technology evolves to help develop new treatment strategies for AF. Our report will focus on a hybrid treatment approach using surgical and electrophysiology approaches providing enhanced treatment options by replicating Cox-Maze IV lesions using skills from each specialty. Closure of the left atrial appendage as part of these procedures enhances protection from late stroke. A team approach provides a cohesive evaluation, treatment, and monitoring plan for patients. Development of successful, less invasive treatment options will help address the growing population of patients with AF.

Safety of MRI in patients with retained cardiac leads

Purpose

To evaluate the safety of MRI in patients with fragmented retained leads (FRLs) through numerical simulation and phantom experiments.

Methods

Electromagnetic and thermal simulations were performed to determine the worst‐case RF heating of 10 patient‐derived FRL models during MRI at 1.5 T and 3 T and at imaging landmarks corresponding to head, chest, and abdomen. RF heating measurements were performed in phantoms implanted with reconstructed FRL models that produced highest heating in numerical simulations. The potential for unintended tissue stimulation was assessed through a conservative estimation of the electric field induced in the tissue due to gradient‐induced voltages developed along the length of FRLs.

Results

In simulations under conservative approach, RF exposure at B₁⁺ ≤ 2 µT generated cumulative equivalent minutes (CEM)₄₃ < 40 at all imaging landmarks at both 1.5 T and 3 T, indicating no thermal damage for acquisition times (TAs) < 10 min. In experiments, the maximum temperature rise when FRLs were positioned at the location of maximum electric field exposure was measured to be 2.4°C at 3 T and 2.1°C at 1.5 T. Electric fields induced in the tissue due to gradient‐induced voltages remained below the threshold for cardiac tissue stimulation in all cases.

Conclusions

Simulation and experimental results indicate that patients with FRLs can be scanned safely at both 1.5 T and 3 T with most clinical pulse sequences.

The 30-day readmission rate of same-day discharge protocol following catheter ablation for atrial fibrillation: a propensity score-matched analysis from National Readmission Database

AIMS

The effectiveness and safety of same-day discharge (SDD) for catheter ablation (CA) for atrial fibrillation (AF) has not been fully elucidated using a large nationwide database. This study aimed to evaluate the all-cause readmission rates within 30-days among patients receiving CA for AF with an SDD protocol compared with a conventional overnight stay (ONS).

METHODS AND RESULTS

We performed a retrospective cohort study using the US Nationwide Readmission Database. The primary outcome was all-cause 30-day readmission following discharge in patients receiving CA and a secondary outcome was requiring total healthcare cost. A 1 : 3 propensity score matching was conducted to compare the safety and efficacy within both SDD and ONS group. Among 30 776 patients [mean 67.2 ± 11.4 years, 12 590 female (41.5%)] who received CA from 2016 through 2018, 440 (1.42%) patients were discharged on the same-day following CA (SDD group), and the remaining 30 336 patients stayed at least one night in the hospital (ONS group). A propensity score analysis generated 1751 matched pairs (440 in the SDD group; 1311 in the ONS group). The 30-day readmission following discharge was not significantly higher in the SDD group than the ONS group (SDD vs. ONS: 12.7% vs. 9.7%; hazard ratio: 1.17, 95% confidence interval: 0.76-1.81, P = 0.47). Healthcare cost was significantly higher in the ONS group ($25 237 ± 14 036 vs. $30 749 ± 16 383; P < 0.01).

CONCLUSION

In this nationwide database study, there was no significant difference in the all-cause 30-day readmission following SDD for CA compared with ONS.

Shared Decision Making in Cardiac Electrophysiology Procedures and Arrhythmia Management

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

Erratum: 2021 ISHNE / HRS / EHRA / APHRS Collaborative Statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology / Heart Rhythm Society / European Heart Rhythm Association / Asia Pacific Heart Rhythm Society

[This corrects the article DOI: 10.1093/ehjdh/ztab001.].

Use of a novel 4D intracardiac echocardiography catheter to guide interventional electrophysiology procedures

INTRODUCTION

Standard two-dimensional (2D), phased-array intracardiac echocardiography (ICE) is routinely used to guide interventional electrophysiology (EP) procedures. A novel four-dimensional (4D) ICE catheter (VeriSight Pro, Philips) can obtain 2D and three-dimensional (3D) volumetric images and cine-videos in real-time (4D). The purpose of this study was to determine the early feasibility and safety of this 4D ICE catheter during EP procedures.

METHODS

The 4D ICE catheter was placed from the femoral vein in ten patients into various cardiac chambers to guide EP procedures requiring transseptal catheterization, including ablation for atrial fibrillation and left atrial appendage closure. 2D- and 3D-ICE images were acquired in real-time by the electrophysiologist. A dedicated imaging expert performed digital steering to optimize and postprocess 4D images.

RESULTS

Eight patients underwent pulmonary vein isolation (cryoballoon in seven patients, pulsed field ablation in one, additional radiofrequency left atrial ablation in one). Two patients underwent left atrial appendage closure. High quality images of cardiac structures, transseptal catheterization equipment, guide sheaths, ablation tools, and closure devices were acquired with the ICE catheter tip positioned in the right atrium, left atrium, pulmonary vein, coronary sinus, right ventricle, and pulmonary artery. There were no complications.

CONCLUSION

This is the first experience of a novel deflectable 4D ICE catheter used to guide EP procedures. 4D ICE imaging is safe and allows for acquisition of high-quality 2D and 3D images in real-time. Further use of 4D ICE will be needed to determine its added value for each EP procedure type.

Trends in Cardiovascular Mortality Related to Atrial Fibrillation in the United States, 2011 to 2018

Background

Prevalence of atrial fibrillation (AF) continues to increase and is associated with significant cardiovascular morbidity and mortality. To inform prevention strategies aimed at reducing the burden of AF, we sought to quantify trends in cardiovascular mortality related to AF in the United States.

Methods and Results

We performed serial cross‐sectional analyses of national death certificate data for cardiovascular mortality related to AF, whereby cardiovascular disease was listed as underlying cause of death and AF as multiple cause of death among adults aged 35 to 84 years using the Centers for Disease Control and Prevention's Wide‐Ranging Online Data for Epidemiologic Research. We calculated age‐adjusted mortality rates per 100 000 population and examined trends over time, estimating average annual percentage change using the Joinpoint Regression Program. Subgroup analyses were performed by race‐sex and across 2 age groups (younger: 35–64 years; older: 65–84 years). A total of 276 373 cardiovascular deaths related to AF were identified in the United States between 2011 and 2018 in decedents aged 35 to 84 years. Age‐adjusted mortality rate increased from 18.0 (95% CI, 17.8–18.2) to 22.3 (95% CI, 22.0–22.4) per 100 000 population between 2011 and 2018. The increase in age‐adjusted mortality rate (average annual percentage change) between 2011 and 2018 was greater among younger decedents (7.4% per year [95% CI, 6.8%–8.0%]) compared with older decedents (3.0% per year [95% CI, 2.6%–3.4%]).

Conclusions

Cardiovascular deaths related to AF are increasing, especially among younger adults, and warrant greater attention to prevention earlier in the life course.

Association of Lower Urinary Tract Symptoms Based on the International Prostate Symptom Score and Cardiovascular Disease

BACKGROUND

Because it is unclear whether lower urinary tract symptoms (LUTS) are associated with cardiovascular disease (CVD) in the Japanese population, we explored the association in general Japanese men aged 55-75 years.Methods and Results:The cross-sectional study included male participants who had both national health checkup data and the International Prostate Symptom Score (IPSS) in the same calendar year between 2009 and 2017. LUTS severity was evaluated by IPSS. A robust Poisson regression model was used to assess the association between LUTS severity and the composite CVD outcome [coronary artery disease (CAD), stroke, or atrial fibrillation (AF)] and each component of the composite outcome. Prevalence ratio (PR) was adjusted for conventional cardiovascular risk factors. Of 16,781 male participants (mean age, 67±5 years), mild LUTS were observed in 9,243 (55.1%); moderate, 6,445 (38.4%); and severe, 1,093 (6.5%). Compared with the mild LUTS group, moderate LUTS [PR 1.18, 95% confidence interval (CI) 1.10-1.25, P<0.001] and severe LUTS (PR 1.38, 95% CI 1.24-1.53, P<0.001) were significantly associated with a higher prevalence of CVD. LUTS severity was associated with higher prevalence of CAD and stroke, but not AF.

CONCLUSIONS

The severity of LUTS was associated with a higher prevalence of CVD, especially CAD and stroke, independent of conventional CVD risk factors.

Reexamination of the Embolic Stroke of Undetermined Source Concept

Occult atrial fibrillation (AF) is a leading cause of stroke of unclear cause. The optimal approach to secondary stroke prevention for these patients remains elusive. The term embolic stroke of undetermined source (ESUS) was coined to describe ischemic strokes in which the radiographic features demonstrate territorial infarcts resembling those seen in patients with confirmed sources of embolism but without a clear source of embolism detected. It was assumed that patients with ESUS had a high rate of occult AF and would benefit from treatment with direct oral anticoagulants, which are at least as effective as vitamin K antagonists for secondary stroke prevention in patients with AF, but with a much lower risk of intracerebral hemorrhage. Two recent large randomized trials failed to show superiority of direct oral anticoagulants over aspirin in ESUS patients. These findings prompt a reexamination of the ESUS concept, with the goal of improving specificity for detecting patients with a cardioembolic cause. Based on the negative trial results, there is renewed interest in the role of long-term cardiac monitoring for AF in patients who fit the current ESUS definition, as well as the clinical implication of detecting AF. Ongoing trials are exploring these questions. Current ESUS definitions do not accurately detect the patients who should be prescribed direct oral anticoagulants, potentially because occult AF is less common than expected in these patients and/or anticoagulants may be less beneficial in patients with ESUS but no AF than they are for patients with stroke with established AF. More specific criteria to identify patients who may be at higher risk for occult AF and reduce their risk of subsequent stroke have been developed and are being tested in ongoing clinical trials.

Inter-Patient Atrial Flutter Classification Using FFT-Based Features and a Low-Variance Stacking Classifier

OBJECTIVE

Atrial Flutter (AFL) is a supraventricular tachyarrhythmia typically arising from a macroreentry circuit that can have variable atrial anatomy. It is often treated by catheter ablation, the success of which depends upon the correct determination of the electroanatomic circuit, generally through invasive electrophysiological (EP) study. We hypothesized that machine learning (ML) methods applied to the diagnostic 12-lead surface electrocardiogram (ECG) could determine the specific circuit prior to any invasive EP study.

METHODS

The 12-lead ECGs were reduced to eight independent leads: I, II, V1 V6. Through an algorithm using ventricular complex cancellation methods, windows of atrial activity in the ECG were uncovered and spectra were generated. Three ML classifier approaches were applied: Support Vector Machine (SVM), Random Forest (RF) and k-Nearest Neighbors (KNN), and their outputs combined using soft voting.

RESULTS

Ten-second surface ECGs taken from 419 AFL patients prior to invasive EP study and ablation were analyzed retrospectively. Of the 419 patients, 285 had typical cavotricuspid isthmus (CTI)-dependent AFL, 41 had atypical right-atrial AFL and 93 had left-atrial AFL, as determined during the subsequent EP study. Lead V5 was found to be most useful giving a test accuracy of 98\% and f1 score of 0.97.

CONCLUSION

We conclude that ML methods have the potential to automatically determine the AFL macroreentry circuit from the surface ECG.

SIGNIFICANCE

The AFL classification method presented in this investigation achieves 95+\% accuracy on an unbalanced inter-patient dataset which has important clinical applications.

External validity of a model to predict postoperative atrial fibrillation after thoracic surgery

OBJECTIVES

A prediction model developed by Passman et al. stratifies patients' risk of postoperative atrial fibrillation (POAF) after major non-cardiac thoracic surgery using 3 simple factors (sex, age and preoperative resting heart rate). The model has neither undergone external validation nor proven to be relevant in current thoracic surgery practice.

METHODS

A retrospective single-centre analysis of all patients who underwent major non-cardiac thoracic surgery (2008-2017) with prospective documentation of incidence and severity of POAF was used for external validation of Passman's derivation sample (published in 2005 with 856 patients). The model calibration was assessed by evaluating the incidence of POAF and patients' risk scores (0-6).

RESULTS

A total of 2054 patients were included. Among them, POAF occurred in 164 (7.9%), compared to 147 (17.2%) in Passman's study. Differences in our sample compared to Passman's sample included mean heart rate (75.7 vs 73.7 bpm, P < 0.001), proportion of patients with hypertension (46.1 vs 29.4%, P < 0.001), proportion of extensive lung resections, particularly pneumonectomy (6.1 vs 21%, P < 0.001) and proportion of minimally invasive surgeries (56.6% vs 0%). The model demonstrated a positive correlation between risk scores and POAF incidence (risk score 1.2% vs 6.16%).

CONCLUSIONS

The POAF model demonstrated good calibration in our population, despite a lower overall incidence of POAF compared to the derivation study. POAF rates were higher among patients with a higher risk score and undergoing procedures with greater intrathoracic dissection. This tool may be useful in identifying patients who are at risk of POAF when undergoing major thoracic surgery and may, therefore, benefit from targeted prophylactic therapy.

Using 5D flow MRI to decode the effects of rhythm on left atrial 3D flow dynamics in patients with atrial fibrillation

PURPOSE

This study used a 5D flow framework to explore the influence of arrhythmia on thrombogenic hemodynamic parameters in patients with atrial fibrillation (AF).

METHODS

A fully self-gated, 3D radial, highly accelerated free-running 5D flow sequence with interleaved four-point velocity-encoding was acquired using an in vitro arrhythmic flow phantom and in 25 patients with a history of AF (68 ± 8 y, 6 female). Self-gating signals were used to calculate AF burden, bin data, and tag each k-space line with its RRLength . Data were binned as an RR-resolved dataset with four RR-interval bins (RR1-RR4, short-to-long) for compressed sensing reconstruction. AF burden was calculated as interquartile range of all intrascan RR-intervals divided by median RR-interval, and left atrial (LA) stasis as the percent of the cardiac cycle where the velocity was <0.1 m/s.

RESULTS

In vitro results demonstrated successful recovery of RR-binned flow curves using RR-resolved 5D flow compared to a real-time PC reference standard. In vivo, 5D flow was acquired in 8:48 minutes. AF burden was significantly correlated with 5D flow-derived peak (PV) and mean (MV) velocity and stasis (|ρ| = 0.54-0.75, P < .001). Sensitivity analyses determined a threshold for low versus high AF burden at 9.7%. High burden patients had increased LA mean stasis (up to +42%, P < .01), and lower MV and PV (-30%, -40.6%, respectively, P < .01). RR4 deviated furthest from respiratory-resolved reconstruction (end-expiration) with increased mean stasis (7.6% ± 14.0%, P = .10) and decreased PV (-12.7 ± 14.2%, P = .09).

CONCLUSIONS

RR-resolved 5D flow can capture temporal and RR-resolved 3D hemodynamics in <10 minutes and offers a novel approach to investigate arrhythmias.

2021 ISHNE/HRS/EHRA/APHRS Expert Collaborative Statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia-Pacific Heart Rhythm Society

Supplemental Digital Content is available in the text.

This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia-Pacific Heart Rhythm Society describes the current status of mobile health technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self-management are novel aspects of mobile health. The promises of predictive analytics but also operational challenges in embedding mobile health into routine clinical care are explored.

2021 ISHNE/ HRS/ EHRA/ APHRS collaborative statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia Pacific Heart Rhythm Society

This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology/ Heart Rhythm Society/ European Heart Rhythm Association/ Asia Pacific Heart Rhythm Society describes the current status of mobile health ("mHealth") technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self‐management are novel aspects of mHealth. The promises of predictive analytics but also operational challenges in embedding mHealth into routine clinical care are explored.

2021 ISHNE/HRS/EHRA/APHRS collaborative statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia Pacific Heart Rhythm Society

This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology/Heart Rhythm Society/European Heart Rhythm Association/Asia Pacific Heart Rhythm Society describes the current status of mobile health (“mHealth”) technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self‐management are novel aspects of mHealth. The promises of predictive analytics but also operational challenges in embedding mHealth into routine clinical care are explored.

2021 ISHNE / HRS / EHRA / APHRS Collaborative Statement on mHealth in Arrhythmia Management: Digital Medical Tools for Heart Rhythm Professionals: From the International Society for Holter and Noninvasive Electrocardiology / Heart Rhythm Society / European Heart Rhythm Association / Asia Pacific Heart Rhythm Society

This collaborative statement from the International Society for Holter and Noninvasive Electrocardiology / Heart Rhythm Society / European Heart Rhythm Association / Asia Pacific Heart Rhythm Society describes the current status of mobile health ("mHealth") technologies in arrhythmia management. The range of digital medical tools and heart rhythm disorders that they may be applied to and clinical decisions that may be enabled are discussed. The facilitation of comorbidity and lifestyle management (increasingly recognized to play a role in heart rhythm disorders) and patient self-management are novel aspects of mHealth. The promises of predictive analytics but also operational challenges in embedding mHealth into routine clinical care are explored.

The future of long-term monitoring following catheter and surgical intervention for atrial fibrillation

Monitoring following catheter or surgical ablation for atrial fibrillation (AF) is an essential tool used to assess outcomes for research purposes and help guide clinical decision making. The most commonly used methods to monitor for postintervention AF include a variety of ambulatory external electrocardiogram monitors, cardiac implantable electronic devices, and more recently, direct to consumer digital health technologies. The traditional metric of ablation success, recurrence > 30 s at 1 year, is below the detection capabilities of almost all monitoring techniques yet still undervalues the efficacy of AF interventions. Measures of AF burden reduction and duration give a more complete assessment of the impact of AF surgeries and ablation. As it is increasingly being recognized that AF burden and duration is related to stroke risk, long-term, inexpensive, noninvasive monitoring methods are needed. Smart phones and watches with AF-detecting capabilities, which are increasingly being used by the majority of U.S. adults, have emerged as viable options to achieve this goal, shifting the paradigm of AF monitoring to a more patient-centered approach.

Digital Health and the Care of the Patient With Arrhythmia

The field of cardiac electrophysiology has been on the cutting edge of advanced digital technologies for many years. More recently, medical device development through traditional clinical trials has been supplemented by direct to consumer products with advancement of wearables and health care apps. The rapid growth of innovation along with the mega-data generated has created challenges and opportunities. This review summarizes the regulatory landscape, applications to clinical practice, opportunities for virtual clinical trials, the use of artificial intelligence to streamline and interpret data, and integration into the electronic medical records and medical practice. Preparation of the new generation of physicians, guidance and promotion by professional societies, and advancement of research in the interpretation and application of big data and the impact of digital technologies on health outcomes will help to advance the adoption and the future of digital health care.

Temporal relationship between atrial fibrillation and ischaemic stroke in a large cohort with continuous rhythm monitoring

Background/Introduction

Atrial fibrillation (AF) increases the risk of ischaemic stroke, but the temporal relationship is uncertain.

Purpose

To assess the temporal relationship between AF episodes and ischaemic stroke in patients with cardiovascular implantable electronic devices (CIED) utilizing a case-crossover analysis.

Methods

We linked a very large U.S. aggregated de-identified electronic health record database (2007–2017), containing claims for ischaemic stroke hospitalizations, to a manufacturer's CIED database with continuous AF monitoring. All stroke patients with ≥120 days of pre-stroke rhythm data were included. For each stroke patient, we compared the presence of a day with ≥5.5 hours of AF (the TRENDS study threshold) in the case period (days 1–30 pre-stroke) to that in the control period (days 91–120 pre-stroke). Matched analyses for dichotomous outcomes generated odds ratios with confidence intervals and p values.

Results

We identified 891 ischaemic stroke patients (71.3±10.5 years, 65% male, 27% pacemakers, 60% defibrillators, 13% insertable cardiac monitors) with continuous monitoring data in the 120 days pre-stroke. The vast majority had either no AF in both the case and control periods (n=682, 77%) or AF in both periods (n=143, 16%), i.e., non-informative records. However, among the 66 patients with informative, discordant arrhythmic states, 52 had AF in the case period versus 14 in the control period, for an odds ratio of 3.71 (95% C.I. 2.06–6.70, p&lt;0.001). Analysed by 5-day periods, stroke risk was markedly increased within 30 days of the AF episode (figure). For days 1–5 following an AF episode, the odds ratio was 9.7 (95% C.I. 5.9–16.1). Risk diminished towards non-AF risk after 30 days.

Conclusion

Our analysis of this largest cohort with continuous rhythm monitoring prior to ischaemic stroke demonstrates that stroke risk is highest within a few days of an episode of AF and diminishes rapidly thereafter. Our findings support a strategy of time-limited anticoagulation for patients with infrequent episodes of AF and available continuous rhythm monitoring.

Funding Acknowledgement

Type of funding source: None

Are all CHA2DS2-VASc risk factors created equal? An assessment of stroke risk among 34,470 patients with CHA2DS2-VASc scores of 1 or 2

Introduction

The CHA2DS2-VASc score is commonly used to assess ischemic stroke risk in patients with documented atrial fibrillation (AF). Whether each combination of CHA2DS2-VASc score 1 or 2 confers a similar stroke risk is poorly understood.

Methods

A de-identified database of aggregated electronic health record (EHR) data from 2007–2017 was used to identify patients not on oral anticoagulation (OAC) who had documented AF and CHA2DS2-VASc scores of 1 or 2. CHA2DS2-VASc=1 groups included patients with only heart failure, hypertension, age 65–74, diabetes, vascular disease or female gender. The 17 possible permutations of CHA2DS2-VASc =2 scores were consolidated into 6 groups: prior stroke/TIA, age &gt;75, 2 co-morbidities, 1 co-morbidity + age 65–74, 1 co-morbidity + female gender, or age 65–74 + female gender. Stroke risk hazard ratios were computed for each of these groups.

Results

A total of 34,470 patients (61.0±12.0 years, 67.3% male) not on OAC with a documented history of AF and CHA2DS2-VASc scores of 1 (n=16,572) or 2 (n=17,898) were identified. The annual risks of ischemic stroke among CHA2DS2-VASc 1 and 2 patients were 0.22% [0.18–0.26] and 0.38% [0.33–0.43], respectively. For CHA2DS2-VASc =1 patients, age 65–74 conferred a greater risk of stroke while female gender conferred a lower risk. For CHA2DS2-VASc =2 patients, prior stroke/TIA conferred a greater risk of stroke while 1 co-morbidity + female gender conferred a lower risk [Figure].

Conclusion

Ischemic stroke risk varies significantly across specific risk factors in patients with CHA2DS2-VASc scores =1 or 2. Therefore, OAC decisions in these patients should consider individual risk factors rather than the aggregate score alone.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Medtronic

Atrial fibrillation ablation success defined by duration of recurrence on cardiac implantable electronic devices

INTRODUCTION

Ablation for atrial fibrillation (AF) has emerged as an effective method of rhythm control. This exploratory analysis aimed to determine how various measures of recurrence would influence the definition of treatment success.

METHODS

Using an electronic health record data set from January 2007 to June 2019 linked with Medtronic cardiac implantable electronic device (CIED) data, patients who underwent a first AF ablation procedure following CIED implantation were identified. Data were analyzed for recurrence of AF stratified by varying definitions of successful ablation. The performance of various simulated external AF monitoring strategies was assessed.

RESULTS

A total of 665 patients were analyzed including 248 with paroxysmal AF (mean age: 66.2 ± 9.3 years, 73.0% male) and 417 patients with persistent AF (mean age: 67.3 ± 9.0 years, 73.6% male). Among patients with paroxysmal AF, survival free from recurrence at 1 year ranged from 28.2% to 72.1% (>6 min and >23 h thresholds, respectively) with an overall median percentage of time in AF reduction of 99.6%. Among patients with persistent AF, survival free from recurrence at 1 year ranged from 24.9% to 60.0% (>6 min and 7 consecutive days > 23 h thresholds, respectively) with an overall median percentage of time in AF reduction of 99.3%. A single 7-day monitoring strategy had a sensitivity of less than 50% for detecting AF greater than 6 min in patients with paroxysmal and persistent AF.

CONCLUSION

In this real-world data set of AF patients with CIEDs undergoing catheter ablation, treatment success varied substantially with different definitions of minimally required AF duration and is significantly impacted by the method of recurrence detection.

Attenuation of Oxidative Injury With Targeted Expression of NADPH Oxidase 2 Short Hairpin RNA Prevents Onset and Maintenance of Electrical Remodeling in the Canine Atrium: A Novel Gene Therapy Approach to Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common heart rhythm disorder in adults and a major cause of stroke. Unfortunately, current treatments of AF are suboptimal because they are not targeted to the molecular mechanisms underlying AF. Using a highly novel gene therapy approach in a canine, rapid atrial pacing model of AF, we demonstrate that NADPH oxidase 2 (NOX2) generated oxidative injury causes upregulation of a constitutively active form of acetylcholine-dependent K+ current (IKACh), called IKH; this is an important mechanism underlying not only the genesis, but also the perpetuation of electric remodeling in the intact, fibrillating atrium.

METHODS

To understand the mechanism by which oxidative injury promotes the genesis and maintenance of AF, we performed targeted injection of NOX2 short hairpin RNA (followed by electroporation to facilitate gene delivery) in atria of healthy dogs followed by rapid atrial pacing. We used in vivo high-density electric mapping, isolation of atrial myocytes, whole-cell patch clamping, in vitro tachypacing of atrial myocytes, lucigenin chemiluminescence assay, immunoblotting, real-time polymerase chain reaction, immunohistochemistry, and Masson trichrome staining.

RESULTS

First, we demonstrate that generation of oxidative injury in atrial myocytes is a frequency-dependent process, with rapid pacing in canine atrial myocytes inducing oxidative injury through the induction of NOX2 and the generation of mitochondrial reactive oxygen species. We show that oxidative injury likely contributes to electric remodeling in AF by upregulating IKACh by a mechanism involving frequency-dependent activation of PKCε (protein kinase C epsilon). The time to onset of nonsustained AF increased by >5-fold in NOX2 short hairpin RNA-treated dogs. Furthermore, animals treated with NOX2 short hairpin RNA did not develop sustained AF for up to 12 weeks. The electrophysiological mechanism underlying AF prevention was prolongation of atrial effective refractory periods, at least in part attributable to the attenuation of IKACh. Attenuated membrane translocation of PKCε appeared to be a likely molecular mechanism underlying this beneficial electrophysiological remodeling.

CONCLUSIONS

NOX2 oxidative injury (1) underlies the onset, and the maintenance of electric remodeling in AF, as well, and (2) can be successfully prevented with a novel, gene-based approach. Future optimization of this approach may lead to a novel, mechanism-guided therapy for AF.

Left Ventricular Extracellular Volume Expansion Is Not Associated with Atrial Fibrillation or Atrial Fibrillation-mediated Left Ventricular Systolic Dysfunction

PURPOSE

To determine whether left ventricular (LV) extracellular volume (ECV) expansion is associated with atrial fibrillation (AF) or AF-mediated LV systolic dysfunction (LVSD) while minimizing the influence of biologic and imaging methodologic confounders.

MATERIALS AND METHODS

This study examined the prevalence of LV ECV expansion in 137 patients with AF (mean age, 62 years ± 11 [standard deviation]; 92 male patients and 45 female patients; 83 paroxysmal and 54 persistent) who underwent preablation cardiovascular MRI. Biologic confounders were minimized by measuring the ECV fraction and excluding patients with severe LV hypertrophy, defined as wall thickness greater than 1.5 cm. Imaging confounders were minimized by using an arrhythmia-insensitive-rapid (AIR) cardiac T1 mapping pulse sequence. Other cardiac functional parameters, including LV ejection fraction (LVEF) and left atrial end-diastolic volume indexed to body surface area, were assessed using cine cardiovascular MRI. A substudy was conducted in 32 patients with no AF (mean age, 54 years ± 16) in sinus rhythm to establish control values and convert these values between the AIR sequence and literature-based modified Look-Locker inversion recovery (MOLLI) values.

RESULTS

The mean ECV was not significantly different (P > .05) between patients with AF with a normal LVEF (24.5% ± 2.8; n = 107), patients with AF with LVSD (24.5% ± 2.5; n = 30), and patients with no AF (24.4% ± 3.8; n = 32), but there was a significant interaction between ECV and CHA₂DS₂-VASc score (P = .045). Compared with the literature data obtained from healthy control patients scanned using MOLLI, 99.3% of patients with AF had ECV below the fibrosis cutoff point (32.8% when converted from MOLLI T1 mapping to AIR T1 mapping), including a subset of patients with AF (n = 28) with low CHA₂DS₂-VASc score (0/1 for men/women).

CONCLUSION

Study results suggest that an LV ECV expansion is not associated with AF or AF-mediated LVSD. Supplemental material is available for this article. © RSNA, 2020See also the commentary by Stillman in this issue.