Association of Atrial Fibrillation Burden and Mortality Among Patients With Cardiac Implantable Electronic Devices.

BACKGROUND: Current estimates of atrial fibrillation (AF)-associated mortality rely on claims- or clinical-derived diagnoses of AF, limit AF to a binary entity, or are confounded by comorbidities. The objective of the present study is to assess the association between device-recognized AF and mortality among patients with cardiac implantable electronic devices capable of sensitive and continuous atrial arrhythmia detection. Secondary outcomes include relative mortality among cohorts with no AF, paroxysmal AF, persistent AF, and permanent AF. METHODS: Using the deidentified Optum Clinformatics US claims database (2015 to 2020) linked to the Medtronic CareLink database, we identified individuals with a cardiac implantable electronic device who transmitted data ≥6 months after implantation. AF burden was assessed during the first 6 months after implantation (baseline period). Subsequent mortality, assessed from claims data, was compared between patients with and those without AF, with adjustment for age, geographic region, insurance type, Charlson Comorbidity Index, and implantation year. RESULTS: Of 21 391 patients (age, 72.9±10.9 years; 56.3% male) analyzed, 7798 (36.5%) had device-recognized AF. During a mean of 22.4±12.9 months (median, 20.1 [12.8-29.7] months) of follow-up, the overall incidence of mortality was 13.5%. Patients with AF had higher adjusted all-cause mortality than patients without AF (hazard ratio, 1.29 [95% CI, 1.20-1.39]; P<0.001). Among those with AF, patients with nonparoxysmal AF had the greatest risk of mortality (persistent AF versus paroxysmal AF: hazard ratio, 1.36 [95% CI, 1.18-1.58]; P<.001; permanent AF versus paroxysmal AF: hazard ratio, 1.23 [95% CI, 1.14-1.34]; P<.001). CONCLUSIONS: After adjustment for potential confounding factors, presence of AF was associated with higher mortality than no AF in our cohort of patients with cardiac implantable electronic devices. Among those with AF, nonparoxysmal AF was associated with the greatest risk of mortality.

Association between high-density mapping of atypical atrial flutter, clinical outcomes and healthcare utilization.

BACKGROUND: Success of atypical atrial flutter (AAFL) ablation has historically been limited by difficulty mapping the complex re-entrant circuits involved. While high-density (HD) mapping has become commonplace in clinical practice, there are limited data on outcomes of HD versus non-HD mapping for AAFL ablation. OBJECTIVE: To compare clinical outcomes and healthcare utilization using HD mapping versus non-HD mapping for AAFL ablation. METHODS: Retrospective analysis of all AAFL procedures between 2005 and 2022 at an academic medical center was conducted. Procedures utilizing a 16-electrode HD Grid catheter and Precision mapping system were compared to procedures using prior generation 10-20 electrode spiral catheters and the Velocity system (Abbott, IL). Cox regression models and Poisson regression models were utilized to examine procedural and healthcare utilization outcomes. Models were adjusted for left ventricular ejection fraction, CHA2DS2-VASc, and history of prior ablation. RESULTS: There were 108 patients (62% HD mapping) included in the analysis. Baseline clinical characteristics were similar between groups. Use of HD mapping was associated with a higher rate of AAFL circuit delineation (92.5% vs. 76%; p = .014) and a greater adjusted procedure success rate, defined as non-inducibility at procedure end, (aRR (95% CI) 1.26 (1.02-1.55) p = .035) than non-HD mapping. HD mapping was also associated with a lower rate of ED visits (aIRR (95% CI) 0.32 (0.14-0.71); p = .007) and hospitalizations (aIRR (95% CI) 0.32 (0.14-0.68); p = .004) for AF/AFL/HF through 1 year. While there was a lower rate of recurrent AFL through 1 year among HD mapping cases (aHR (95% CI) 0.60 (0.31-1.16) p = .13), statistical significance was not met likely due to the low sample size and higher rate of ambulatory rhythm monitoring in the HD group (61% vs. 39%, p = .025). CONCLUSION: Compared to non-HD mapping, AAFL ablation with HD mapping is associated with improvements in the ability to define the AAFL circuit, greater procedural success, and a reduction in the number of ED visits and hospitalization for AF/AFL/HF.

MRI Investigation of the Association of Left Atrial and Left Atrial Appendage Hemodynamics with Silent Brain Infarction.

BACKGROUND: Left atrial (LA) myopathy is thought to be associated with silent brain infarctions (SBI) through changes in blood flow hemodynamics leading to thrombogenesis. 4D-flow MRI enables in-vivo hemodynamic quantification in the left atrium (LA) and LA appendage (LAA). PURPOSE: To determine whether LA and LAA hemodynamic and volumetric parameters are associated with SBI. STUDY TYPE: Prospective observational study. POPULATION: A single-site cohort of 125 Participants of the multiethnic study of atherosclerosis (MESA), mean age: 72.3 ± 7.2 years, 56 men. FIELD STRENGTH/SEQUENCE: 1.5T. Cardiac MRI: Cine balanced steady state free precession (bSSFP) and 4D-flow sequences. Brain MRI: T1- and T2-weighted SE and FLAIR. ASSESSMENT: Presence of SBI was determined from brain MRI by neuroradiologists according to routine diagnostic criteria in all participants without a history of stroke based on the MESA database. Minimum and maximum LA volumes and ejection fraction were calculated from bSSFP data. Blood stasis (% of voxels <10 cm/sec) and peak velocity (cm/sec) in the LA and LAA were assessed by a radiologist using an established 4D-flow workflow. STATISTICAL TESTS: Student's t test, Mann-Whitney U test, one-way ANOVA, chi-square test. Multivariable stepwise logistic regression with automatic forward and backward selection. Significance level P < 0.05. RESULTS: 26 (20.8%) had at least one SBI. After Bonferroni correction, participants with SBI were significantly older and had significantly lower peak velocities in the LAA. In multivariable analyses, age (per 10-years) (odds ratio (OR) = 1.99 (95% confidence interval (CI): 1.30-3.04)) and LAA peak velocity (per cm/sec) (OR = 0.87 (95% CI: 0.81-0.93)) were significantly associated with SBI. CONCLUSION: Older age and lower LAA peak velocity were associated with SBI in multivariable analyses whereas volumetric-based measures from cardiac MRI or cardiovascular risk factors were not. Cardiac 4D-flow MRI showed potential to serve as a novel imaging marker for SBI. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 2.

"Pill-in-Pocket" anticoagulation for stroke prevention in atrial fibrillation.

Uninterrupted anticoagulation for atrial fibrillation (AF), regardless of AF burden, is deeply rooted in practice since the early anticoagulation trials. However, uninterrupted anticoagulation is not without risks, and may not be beneficial for allcomers with a history of AF. Indeed, contemporary data that support a critical duration threshold of AF that benefits from anticoagulation, and a temporal association between stroke and multihour AF episodes, compel the study of a more targeted approach to AF anticoagulation. In this review, we discuss data that support further investigation of "pill in the pocket" anticoagulation for AF, and introduce the pivotal Rhythm Evaluation for Anticoagulation Therapy for Atrial Fibrillation (REACT-AF) trial that will robustly evaluate this strategy.

Accuracy of the Apple watch for detection of AF: A multicenter experience.

INTRODUCTION: The Apple watch (AW) irregular rhythm notification (IRN) feature uses photoplethysmography to identify prolonged episodes of irregular rhythm suggestive of atrial fibrillation (AF). IRN is FDA cleared for those with no previous history of AF, however, these devices are increasingly being used for AF management.  The objective of the present study was to determine the accuracy of the IRN in subjects with a previous diagnosis of nonpermanent AF. METHODS: Subjects with a history of nonpermanent AF and either an insertable cardiac monitor (ICM) or cardiac implanted electronic device (CIED) with <5% ventricular pacing were fitted with an AW Series 5 for 6 months. AF episodes were compared between the ICM/CIED and IRN. The primary endpoints were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the IRN by subject for AF ≥1 h. Secondary endpoints were sensitivity and PPV by AF episode ≥1 h. Analysis was limited to a maximum of 10 ICM/CIED episodes per subject and included only those AF episodes occurring during active AW use confirmed by activity data. RESULTS: Thirty participants were enrolled. Mean age was 65.4 ± 12.2 years and 40% were female. There were 10 ICMs and 20 CIEDs. Eleven subjects had AF on ICM/CIED while the AW was worn, of whom 8 were detected by IRN. There were no false positive IRN detections by subject ("by subject" 72% sensitivity, 100% specificity, 100% PPV, and 90% NPV). Five subjects had AF only when the AW was not worn. There were a total of 70 AF episodes on ICM/CIED, 35 of which occurred while the AW was being worn. Of these, 21 were detected by IRN with 1 false positive ("by episode" sensitivity = 60.0%, PPV = 95.5%). CONCLUSION: In a population with known AF, the AW IRN had a low rate of false positive detections and high specificity. Sensitivity for detection by subject and by AF episode was lower. The current IRN algorithm appears accurate for AF screening as currently cleared, but increased sensitivity and wear times would be necessary for disease management.

Characterization of baseline clinical factors associated with incident worsening kidney function in patients with non-valvular atrial fibrillation: the Hokuriku-Plus AF Registry.

Evidence suggests that atrial fibrillation (AF) could increase the risk of worsening kidney function (WKF) which is linked to an increased risk of stroke, bleeding, and death in AF patients. However, limited data exist regarding the factors that could lead to WKF in these patients. Therefore, we sought to identify the potential factors associated with the development of WKF in patients with non-valvular AF (NVAF). We analyzed prospectively recruited 1122 NVAF patients [men 71.9%, median age 73.0 years (interquartile range: 66.0-79.0)] with a baseline estimated glomerular filtration rate (eGFR) ≥ 15 mL/min/1.73 m2 from the Hokuriku-Plus AF Registry. The primary outcome was incident WKF, defined as the %eGFR change from the baseline ≥ 30% during the follow-up period. We evaluated the association between baseline variables and incident WKF using univariate and multivariate Cox proportional hazard models. We also evaluated the non-linear association between the identified factors and incident WKF. During a median follow-up period of 3.0 years (interquartile range: 2.7-3.3), incident WKF was observed in 108 patients (32.6 per 1000 person-years). Compared to the patients without incident WKF, the patients with incident WKF were older and had a higher prevalence of heart failure (HF), diabetes mellitus (DM), and vascular disease at baseline. Those who experienced incident WKF also had higher diastolic blood pressure, lower hemoglobin, lower eGFR, higher B-type natriuretic peptide (BNP) and used warfarin more frequently. Upon multivariate analysis, age ≥ 75 years, HF, DM, and anemia were independently associated with incident WKF. Additionally, age and hemoglobin were linearly associated with the risk of incident WKF, whereas a J- or U-shaped association was observed for HbA1c and BNP. Age ≥ 75 years, HF, DM, and anemia were associated with the development of WKF in Japanese patients with NVAF. In patients with these risk factors, a careful monitoring of the kidney function and appropriate interventions may be important when possible.

The future of long-term monitoring after catheter and surgical ablation for atrial fibrillation.

In recent years, there has been an emergence of long-term cardiac monitoring devices, particularly as they relate to nonprescribed, user-initiated, wearable- and/or, smartphone-based devices. With these new available data, practitioners are challenged to interpret these data in the context of routine clinical decision-making. While there are many potential uses for long-term rhythm monitoring, in this review, we will focus on the evolving role of this technology in atrial fibrillation (AF) monitoring after catheter and/or surgical ablation. Here, we explore the landscape of prescription-based tools for long-term rhythm monitoring; investigate commercially available technologies that are accessible directly to patients, and look towards the future with investigative technologies that could have a growing role in this space.

Esophageal temperature management during cryoballoon ablation for atrial fibrillation.

INTRODUCTION: Esophageal thermal injury (ETI) is a well-recognized complication of atrial fibrillation (AF) ablation. Previous studies have demonstrated that direct esophageal cooling reduces ETI during radiofrequency AF ablation. The purpose of this study was to evaluate the use of an esophageal warming device to prevent ETI during cryoballoon ablation (CBA) for AF. METHODS: This prospective, double-blinded study enrolled 42 patients with symptomatic AF undergoing CBA. Patients were randomized to the treatment group with esophageal warming (42°C) using recirculated water through a multilumen, silicone tube inserted into the esophagus (EnsoETM®; Attune Medical) (WRM) or the control group with a luminal single-electrode esophageal temperature monitoring probe (LET). Patients underwent upper endoscopy esophagogastroduodenoscopy (EGD) the following day. ETI was classified into four grades. RESULTS: Baseline patient characteristics were similar between groups. Procedural characteristics including number of freezes, total freeze time, early freeze terminations, coldest balloon temperature, procedure duration, posterior wall ablation, and proton pump inhibitor and transesophageal echocardiogram use before procedure were not different between groups. The EGD was completed in 40/42 patients. There was significantly more ETI in the WRM group compared to the LET group (n = 8 [38%] vs. n = 1 [5%], p = 0.02). All ETI lesions were grade 1 (erythema) or 2 (superficial ulceration). Total freeze time in the left inferior pulmonary vein was predictive of ETI (360 vs. 300 s, p = 0.03). CONCLUSION: Use of a luminal heat exchange tube for esophageal warming during CBA for AF was paradoxically associated with a higher risk of ETI.

Mobile Health for Arrhythmia Diagnosis and Management.

Palpitations are a common symptom managed by general practitioners and cardiologists; atrial fibrillation (AF) is the most common arrhythmia in adults. The recent commercial availability of smartphone-based devices and wearable technologies with arrhythmia detection capabilities has revolutionized the diagnosis and management of these common medical issues, as it has placed the power of arrhythmia detection into the hands of the patient. Numerous mobile health (mHealth) devices that can detect, record, and automatically interpret irregularities in heart rhythm and abrupt changes in heart rate using photoplethysmography (PPG)- and electrocardiogram-based technologies are now commercially available. As opposed to prescription-based external rhythm monitoring approaches, these devices are more inexpensive and allow for longer-term monitoring, thus increasing sensitivity for arrhythmia detection, particularly for patients with infrequent symptoms possibly due to cardiac arrhythmias. These devices can be used to correlate symptoms with cardiac arrhythmias, assess efficacy and toxicities of arrhythmia therapies, and screen the population for serious rhythm disturbances such as AF. Although several devices have received clearance for AF detection from the United States Food & Drug Administration, limitations include the need for ECG confirmation for arrhythmias detected by PPG alone, false positives, false negatives, charging requirements for the battery, and financial cost. In summary, the growth of commercially available devices for remote, patient-facing rhythm monitoring represents an exciting new opportunity in the care of patients with palpitations and known or suspected dysrhythmias. Physicians should be familiar with the evidence that underlies their added value to patient care and, importantly, their current limitations.

Atrial fibrillation and atrial cardiomyopathies.

Atrial fibrillation (AF) is the most common arrhythmia among adults. While there have been incredible advances in the management of AF and its clinical sequelae, investigation of atrial cardiomyopathies (ACMs) is becoming increasingly more prominent. ACM refers to the electromechanical changes-appreciated subclinically and/or clinically-that underlie atrial dysfunction and create an environment ripe for the development of clinically apparent AF. There are several subtypes of ACM, distinguished by histologic features. Recent progress in cardiovascular imaging, including echocardiography with speckle-tracking (e.g., strain analysis), cardiovascular magnetic resonance imaging (CMR), and atrial 4-D flow CMR, has enabled increased recognition of ACM. Identification of ACM and its features carry clinical implications, including elevating a patient's risk for development of AF, as well as associations with outcomes related to catheter-based and surgical AF ablation. In this review, we explore the definition and classifications of ACM, its complex relationship with clinical AF, imaging modalities, and clinical implications. We propose next steps for a more unified approach to ACM recognition that can direct further research into this complex field.

Evaluation of image quality of wideband single-shot late gadolinium-enhancement MRI in patients with a cardiac implantable electronic device.

INTRODUCTION: While wideband segmented, breath-hold late gadolinium-enhancement (LGE) cardiovascular magnetic resonance (CMR) has been shown to suppress image artifacts associated with cardiac-implanted electronic devices (CIEDs), it may produce image artifacts in patients with arrhythmia and/or dyspnea. Single-shot LGE is capable of suppressing said artifacts. We sought to compare the performance of wideband single-shot free-breathing LGE against the standard and wideband-segmented LGEs in CIED patients. METHODS AND RESULTS: We retrospectively identified all 54 consecutive patients (mean age: 61 ± 15 years; 31% females) with CIED who had undergone CMR with standard segmented, wideband segmented, and/or wideband single-shot LGE sequences as part of quality assurance for determining best clinical practice at 1.5 T. Two raters independently graded the conspicuity of myocardial scar or normal myocardium and the presence of device artifact level on a 5-point Likert scale (1: worst; 3: acceptable; 5: best). Summed visual score (SVS) was calculated as the sum of conspicuity and artifact scores (SVS ≥ 6 defined as diagnostically interpretable). Median conspicuity and artifact scores were significantly better for wideband single-shot LGE (F = 24.2, p < .001) and wideband-segmented LGE (F = 20.6, p < .001) compared to standard-segmented LGE. Among evaluated myocardial segments, 72% were deemed diagnostically interpretable-defined as SVS ≥ 6-for standard-segmented LGE, 89% were deemed diagnostically interpretable for wideband-segmented LGE, and 94% segments were deemed diagnostically interpretable for wideband single-shot LGE. CONCLUSIONS: Wideband single-shot LGE and wideband-segmented LGE produced similarly improved image quality compared to standard LGE.

Impact of pre-ablation weight loss on the success of catheter ablation for atrial fibrillation.

INTRODUCTION: Obesity is an established risk factor for recurrent atrial fibrillation (AF) after ablation. The impact of pre-procedure weight changes on freedom from AF (FFAF) after ablation in obese and nonobese patients is unknown. METHODS: A single-center retrospective cohort study of patients undergoing pulmonary vein isolation was performed. Before ablation, all candidates were encouraged to adopt healthy lifestyle habits according to American Heart Association guidelines, including weight loss, by their physician. The primary endpoint was FFAF through 1-year after completion of the 3-month blanking period. RESULTS: Of the 601 patients (68% male; average age 62.1 ± 10.3 years) included in analysis, 234 patients (38.9%) were obese (body mass index ≥ 30) and 315 (52.4%) had paroxysmal AF. FFAF was observed in 420 patients (69.9%) at 15 months. Percent change in weight that occurred during the year before ablation independently predicted FFAF through 15-months in all patients (adjusted odds ratio = 1.17, 95% confidence interval: 1.11-1.23). Subgroup analyses based on paroxysmal vs persistent AF, presence of obesity, and history of prior ablation were performed. Percent change in weight over the year before ablation was independently associated with FFAF in all subgroups except nonobese patients with persistent AF. CONCLUSION: Pre-ablation weight loss was associated with FFAF in both obese and nonobese patients. Further studies are needed to define the optimal approach to weight loss before AF ablation.

Cardiovascular Risk Factors in Young Adolescents: Results from the National Health and Nutrition Examination Survey 1988-2016.

OBJECTIVES: Lifestyle behaviors relevant to cardiovascular health are learned during childhood and continued into adulthood. Children and adolescents who participate in unhealthy behaviors have a higher lifetime risk of cardiovascular disease in adulthood. Public health institutions publish behavior and clinical recommendations designed for adolescents to reduce their lifetime cardiovascular risk. We assessed the prevalence and trends of cardiovascular-relevant behaviors and clinical tests among early adolescents using a nationally representative database. METHODS: In 2020, we compared the prevalence of cardiovascular risk factors among 1408 adolescents surveyed from 1988 to 1994 with that of 1812 adolescents surveyed from 2011 to 2016 by obtaining and comparing measures on physical activity, diet, body mass index, smoking status, cholesterol levels, hemoglobin A1c, sodium intake, and blood pressure. RESULTS: The prevalence of adherence to the current recommendations regarding physical activity, diet, and body weight declined over time. Conversely, the prevalence of adhering to recommendations to avoid smoking increased. Clinical indicators, including blood pressure control and normal measures of hemoglobin A1c and total serum cholesterol, showed mixed results, with more individuals showing signs of hyperglycemia, fewer showing signs of hypercholesterolemia, and the percentage of individuals with abnormal blood pressure remaining the same. The use of cardiometabolic medications also increased during the study period. Finally, the number of adolescents with all seven cardiovascular protective factors declined significantly during the study period, from 27.6% to 9.6%. CONCLUSIONS: Modern American teenagers aged 12 to 16 years have more cardiovascular risk factors relating mostly to diet, exercise, and obesity than those of a prior generation; however, smoking rates have also declined precipitously.

Stroke Risk as a Function of Atrial Fibrillation Duration and CHA2DS2-VASc Score.

BACKGROUND: Studies of patients with cardiovascular implantable electronic devices show a relationship between atrial fibrillation (AF) duration and stroke risk, although the interaction with CHA2DS2-VASc score is poorly defined. The objective of this study is to evaluate rates of stroke and systemic embolism (SSE) in patients with cardiovascular implantable electronic devices as a function of both CHA2DS2-VASc score and AF duration. METHODS: Data from the Optum electronic health record deidentified database (2007-2017) were linked to the Medtronic CareLink database of cardiovascular implantable electronic devices capable of continuous AF monitoring. An index date was assigned as the later of either 6 months after device implantation or 1 year after electronic health record data availability. CHA2DS2-VASc score was assessed using electronic health record data before the index date. Maximum daily AF burden (no AF, 6 minutes-23.5 hours, and >23.5 hours) was assessed over the 6 months before the index date. SSE rates were computed after the index date. RESULTS: Among 21 768 nonanticoagulated patients with cardiovascular implantable electronic devices (age, 68.6±12.7 years; 63% male), both increasing AF duration (P<0.001) and increasing CHA2DS2-VASc score (P<0.001) were significantly associated with annualized risk of SSE. SSE rates were low in patients with a CHA2DS2-VASc score of 0 to 1 regardless of device-detected AF duration. However, stroke risk crossed an actionable threshold defined as >1%/y in patients with a CHA2DS2-VASc score of 2 with >23.5 hours of AF, those with a CHA2DS2-VASc score of 3 to 4 with >6 minutes of AF, and patients with a CHA2DS2-VASc score ≥5 even with no AF. CONCLUSIONS: There is an interaction between AF duration and CHA2DS2-VASc score that can further risk-stratify patients with AF for SSE and may be useful in guiding anticoagulation therapy.

Patient-reported outcomes after cryoballoon ablation are equivalent between moderate sedation and general anesthesia.

INTRODUCTION: Moderate sedation (MS) during cryoballoon ablation (CBA) avoids risks of general anesthesia (GA) and improves electrophysiology (EP) lab throughput. However, one barrier to the use of MS is the potential for patient discomfort. The objective of this study was to compare patient-reported outcome measures following CBA for paroxysmal atrial fibrillation (pAF) under MS and GA. METHODS AND RESULTS: Consecutive patients undergoing a first CBA for pAF under GA or MS were prospectively enrolled. The sedation method was assigned based on patient and provider preference, and perceived airway risk. The primary outcomes were quality of recovery (measured using a validated 40 question survey; QoR-40) and likelihood to recommend (LTR) the procedure and sedation method (measured by Likert scale). Secondary outcomes were acute pulmonary vein (PV) isolation rate, procedure, fluoroscopy and ablation times, and complication rates. Forty-seven GA and 53 MS patients were included. The mean age was 64.9 ± 9.4 years and mean CHA2 DS2 -VASc score was 2.0 ± 1.4. QoR-40 scores were 184.6 ± 16.4 for GA and 187.6 ± 10.2 for MS (P = .28). LTR responses were similar between groups. Mean procedure times were 148.2 ± 56.0 minutes for GA and 129.4 ± 31.4 minutes for MS (P = .038). Fluoroscopy and ablation times were similar between groups. A total of 100% (409/409) of PVs were acutely isolated. One hemopericardium occurred in the MS group requiring pericardiocentesis. CONCLUSION: MS for CBA offers an alternative to GA that is safe and well-tolerated by patients with comparable success rates and improved EP lab throughput.

Repeat pulmonary vein isolation with or without FIRM-guided ablation for recurrent atrial fibrillation with pulmonary vein reconnection.

INTRODUCTION: Focal impulse and rotor modulation (FIRM) ablation can be used to target nonpulmonary vein (PV) sources of atrial fibrillation (AF). No published studies have compared freedom from atrial fibrillation (FFAF) after pulmonary vein reisolation (PVRI) plus FIRM to PVRI alone in patients with reconnected PVs undergoing repeat ablation. METHODS: A 3:1 matched retrospective cohort study was performed on 21 patients with recurrent AF and PV reconnection who underwent PVRI plus FIRM-guided ablation and 63 patients with recurrent AF treated with PVRI alone at a single institution. All patients in the PVRI-alone cohort had cryoballoon PVRI at the time of repeat ablation without additional lesion sets for AF. Cases were matched based on the type of AF (paroxysmal vs nonparoxysmal), left atrial diameter (±4 mm), left ventricular ejection fraction (±10%), duration of AF (±18 months), and age (±5 years). The primary endpoint was FFAF after a 3-month blanking period. RESULTS: Out of 53 total FIRM cases performed at Northwestern Memorial Hospital between 2015 and 2017, 21 patients had PVRI plus FIRM for recurrent AF with PV reconnection. These patients had an average of 3.3 ± 2.1 rotors (60% left atrial) ablated. Over a median follow-up time of 24.7 months (interquartile range, 13-36 months), patients in the PVRI-alone cohort demonstrated a higher rate of FFAF (n = 35; 55.6%) than patients in the PVRI plus FIRM-guided ablation cohort (n = 7; 33.3%) (logrank P = .049). CONCLUSION: In patients undergoing repeat ablation for AF with PV reconnection, PVRI plus FIRM did not increase FFAF compared to PVRI alone.

Left ventricular extracellular volume expansion does not predict recurrence of atrial fibrillation following catheter ablation.

INTRODUCTION: A recent study reported that diffuse left ventricular (LV) fibrosis is a predictor of atrial fibrillation (AF) recurrence following catheter ablation, by measuring postcontrast cardiac T1 (an error prone metric as per the 2017 Society for Cardiovascular Magnetic Resonance consensus statement) using an inversion-recovery pulse sequence (an error prone method in arrhythmia) in AF ablation candidates. The purpose of this study was to verify the prior study, by measuring extracellular volume (ECV) fraction (an accurate metric) using a saturation-recovery pulse sequence (accurate method in arrhythmia). METHODS AND RESULTS: This study examined 100 AF patients (mean age = 62 ± 11 years, 69 males and 31 females, 67 paroxysmal [pAF] and 33 persistent [peAF]) who underwent a preablation cardiovascular magnetic resonance (CMR) exam. LV ECV and left atrial (LA) and LV functional parameters were quantified using standard analysis methods. During an average follow-up period of 457 ± 261 days with 4 ± 3 rhythm checks per patient, 72 patients maintained sinus rhythm. Between those who maintained sinus rhythm (n = 72) and those who reverted to AF (n = 28), the only clinical characteristic that was significantly different was age (60 ± 12 years vs 66 ± 9 years); for CMR metrics, neither mean LV ECV (25.1 ± 3.3% vs 24.7 ± 3.7%), native LV T1 (1093.8 ± 73.5 ms vs 1070.2 ± 115.9 ms), left ventricular ejection fraction (54.1 ± 11.2% vs 55.7 ± 7.1%), nor LA end diastolic volume/body surface area (42.4 ± 14.8 mL/m2 vs 43.4 ± 19.6 mL/m2 ) were significantly different (P ≥ .23). According to Cox regression tests, none of the clinical and imaging variables predict AF recurrence. CONCLUSION: Neither LV ECV nor other CMR metrics predict recurrence of AF following catheter ablation.

Racial Disparity in the Prescription of Anticoagulants and Risk of Stroke and Bleeding in Atrial Fibrillation Patients.

BACKGROUND: Oral anticoagulant (OAC) therapy is proven to be effective at reducing risk of stroke in patients with atrial fibrillation (AF). However, racial minorities with AF are less likely to be prescribed vitamin K anticoagulants (VKA). There is little information on the racial disparity in the prescription of the non-vitamin K oral anticoagulants (NOACs) and the associated risks of stroke and bleeding. METHODS: We used data from the Northwestern Medicine Enterprise Data Warehouse - a joint initiative across 11 Northwestern Medicine affiliated healthcare centers within metropolitan Chicago, Illinois. Newly diagnosed AF patients between Jan, 2011 and Dec, 2017 with CHA2DS2VASc (congestive heart failure, hypertension, age ≥75 years, diabetes, stroke/transient ischemic attack, vascular disease, age 65 to 74 years, female sex) score of 2 or more and no prior history of stroke or major bleeding were eligible. Logistic regression was used to examine differences in the prescription of any OAC and NOACs by race. Racial differences in the associations of NOACs prescription with incident stroke (a composite of ischemic and hemorrhagic stroke and cerebral embolism) and major bleeding were evaluated using Cox regression. RESULTS: Among 11,575 newly diagnosed AF patients with CHA2DS2VASc score of 2 or more, 48.7% (47.8-49.6) were on any OAC and among those 40.1% (38.8.3-41.4) received any NOACs. After adjusting for age, gender, income, insurance status, and stroke risk factors, the odds of receiving any OAC was .69 (95% CI: .58-.83) in blacks, .74 (.53-1.903) in Hispanics, and .75 (.58-.95) in Asians compared to whites. Among anticoagulated patients, blacks and Hispanics had significantly lower odds of receiving NOACs: .72 (.53-.97) and .53 (.29-.99), respectively. Use of NOACs, as compared to VKAs, was associated with significantly lower risk of stroke [.52(.31-.85)] and bleeding [.72(.54-.95)] in whites but not in non-whites [stroke: .71 (.22-2.31); bleeding .83(.43-1.57)] independent of other risk factors. CONCLUSIONS: Racial minorities with AF who are at risk of stroke were less likely to receive any OAC and NOACs specifically compared to whites even after accounting for insurance status, income, and stroke risk factors. Independent of other risk factors, use of NOACs as compared to VKA was associated with significantly lower risk of stroke and bleeding only in whites but not in non-whites.

Changes in the specific absorption rate (SAR) of radiofrequency energy in patients with retained cardiac leads during MRI at 1.5T and 3T.

PURPOSE: To evaluate the local specific absorption rate (SAR) and heating around retained cardiac leads during MRI at 64 MHz (1.5T) and 127 MHz (3T) as a function of RF coil type and imaging landmark. METHODS: Numerical models of retained cardiac leads were built from CT and X-ray images of 6 patients with retained cardiac leads. Electromagnetic simulations and bio-heat modeling were performed with MRI RF body and head coils tuned to 64 MHz and 127 MHz and positioned at 9 different imaging landmarks covering an area from the head to the lower limbs. RESULTS: For all patients and at both 1.5T and 3T, local transmit head coils produced negligible temperature rise ( Δ T < 0.1 ° C ) for ‖ ‖ B 1 + ‖ ‖ ≤ 3 µ T . For body imaging with quadrature-driven coils at 1.5T, Δ T during a 10-min scan remained < 3°C at all imaging landmarks for ‖ ‖ B 1 + ‖ ‖ ≤ 3 µ T and <6°C for ‖ ‖ B 1 + ‖ ‖ ≤ 4 µ T . For body imaging at 3T, Δ T during a 10-min scan remained < 6°C at all imaging landmarks for ‖ ‖ B 1 + ‖ ‖ ≤ 2 µ T . For shorter pulse sequences up to 2 min, Δ T remained < 6°C for ‖ ‖ B 1 + ‖ ‖ ≤ 3 µ T . CONCLUSION: For the models based on 6 patients studied, simulations suggest that MRI could be performed safely using a local head coil at both 1.5T and 3T, and with a body coil at 1.5T with pulses that produced ‖ ‖ B 1 + ‖ ‖ ≤ 4 µ T . MRI at 3T could be performed safely in these patients using pulses with ‖ ‖ B 1 + ‖ ‖ ≤ 2 µ T .

Patient characteristics as predictors of recurrence of atrial fibrillation following cryoballoon ablation.

BACKGROUND: While several studies have evaluated predictors for atrial fibrillation (AF) recurrence following catheter ablation, there are limited data specific to cryoballoon ablation (CBA). METHODS: We analyzed a prospective registry of patients at a single institution who underwent CBA. Recurrence of AF (RAF) was defined as recurrence of AF by 12-month follow-up, excluding the 3-month blanking period. Univariate analysis was performed to evaluate predictors of RAF. Receiver operating characteristic analysis was used to compare and evaluate the performance of various risk scores for discriminating risk of RAF. RESULTS: There were 542 patients included in the analysis with mean age 61.3 ± 10.6 years, 67.9% male, and 51.6% paroxysmal AF (PAF). Overall, only left atrial diameter (LAD) > 40 mm and ERAF (early recurrence of AF within 0-3 month blanking period) were significant predictors of RAF. In the PAF specific subgroup, LAD > 40 mm, AF duration > 12 months, prior stroke or transient ischemic attack, ERAF, and having previously failed an antiarrhythmic drug were significant predictors of RAF. In persistent AF (PeAF) subgroup, obstructive sleep apnea (OSA) and ERAF were significant predictors of RAF. Out of clinical risk scores tested, BASEAF2 had the highest performance with area under the curve of 0.646 (95% confidence interval [0.548, 0.708]; P < .01). CONCLUSIONS: In this single-center retrospective study of CBA, we found only LAD > 40 mm and ERAF to be predictors of RAF. We identified OSA as a potential targetable risk factor in PeAF patients undergoing CBA. Out of risk scores tested for discriminating risk of RAF, BASEAF2 had the best performance.