Concomitant ablation of atrial fibrillation: New pacemakers and early rhythm recovery.

OBJECTIVE: New permanent pacemaker (PPM) implantation after concomitant atrial fibrillation (AF) ablation has been associated with surgical ablation (SA). We sought to determine factors for PPM use as well as early rhythm recovery. METHODS: From 2004 through 2019, 6135 patients underwent valve surgery and were grouped: No AF (n = 4584), AF no SA (n = 346), and AF with SA (n = 1205) to evaluate predischarge PPM and 3-month rhythm recovery (intrinsic heart rate >40 beats per minute). RESULTS: Overall, 282 (4.6%) patients required a predischarge PPM: atrioventricular node dysfunction in 75.3%, sick sinus syndrome in 19.1%, both (5%), and indeterminate (0.7%). Patients with AF had more PPMs: AF with SA (7.9%) versus AF no SA (6.9%) versus No AF (3.6%) (P < .001). For patients with AF, PPM rates were not significantly higher for ablation patients (7.6% SA vs 6.9% AF no SA; P = .56). There were differences in PPM by SA lesion set (biatrial 12.8%; left atrial only 6.1%; pulmonary vein isolation 3.0%; P < .001). Among patients with AF treated with 3-month PPM follow-up, rhythm recovery was common (35 out of 62 [56.5%]) and did not differ by lesion set. Rhythm recovery was seen in 63 out of 141 (44.7%) in the atrioventricular node dysfunction group versus 24 out of 35 (68.6%) in the sick sinus syndrome group (P = .011). In propensity score-matched groups, late survival was similar (P = .63) for new PPM patients. CONCLUSIONS: Avoiding conduction system trauma and delaying implantation reduces the need for postoperative PPM. Rhythm recovery within 3 months is frequent, especially for patients with sick sinus syndrome. A conservative approach to the implantation of a new PPMs is warranted.

Validation of the SCALE-CryoAF risk model to predict very late return of atrial fibrillation after cryoballoon ablation.

BACKGROUND: To date, few risk models have been validated to predict recurrent atrial fibrillation (AF) >1 year after ablation. The SCALE-CryoAF score was previously derived to predict very late return of AF (VLRAF) >1 year following cryoballoon ablation (CBA), with strong predictive ability. In this study, we aim to validate the SCALE-CryoAF score for VLRAF after CBA in a novel patient cohort. METHODS: Retrospective analysis of a prospectively maintained single-center database was performed. Inclusion criteria were pulmonary vein isolation using CBA 2017-2020. Exclusion criteria included prior ablation, <1-year follow-up, lack of pre-CBA echocardiogram, additional ablation lesion sets, and documented AF recurrence 90-365 days post-CBA. The area under the curve (AUC) of SCALE-CryoAF was compared to the derivation value and other established risk models. RESULTS: Among 469 CBA performed, 241 (61% male, 62.8 ±11.7 years old) cases were included in analysis. There were 37 (15.4%) patients who developed VLRAF. Patients with VLRAF had a higher SCALE-CryoAF score (VLRAF 5.4 ± 2.7; no VLRAF 3.1 ± 2.9; p<0.001). SCALE-CryoAF was linearly associated with VLRAF (y=14.35x-11.72, R2=0.99), and a score > 5 had a 32.7% risk of VLRAF. The SCALE-CryoAF risk model predicted VLRAF with an AUC of 0.74, which was similar to the derivation value (AUCderivation: 0.73) and statistically superior to MB-LATER, CHA2DS2-VASc, and CHADS2 scores. CONCLUSIONS: The current analysis validates the ability of SCALE-CryoAF to predict VLRAF after CBA in a novel patient cohort. Patients with a high SCALE-CryoAF score should be monitored closely for recurrent AF >1 year following CBA.

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.

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.

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.

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.

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.

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.

Improvement in renal function following cryoballoon ablation for atrial fibrillation.

PURPOSE: Patients with chronic kidney disease are predisposed to heart rhythm disorders including atrial fibrillation (AF). Several studies have suggested that radiofrequency catheter ablation of AF improves renal function. However, little data exists for pulmonary vein isolation with cryoballoon ablation (CBA). The purpose of this study is to assess change in renal function following CBA for AF. METHOD: This is a single-center retrospective study that included patients who underwent CBA for AF between 2011 and 2016. Patients were grouped by baseline-estimated glomerular filtration rate (eGFR): ≥ 90 (Stage G1), 60-89.9 (Stage G2), and 30-59.9 mL/min/1.73 m2 (Stage G3). Change in eGFR was assessed > 3 months post-ablation. RESULTS: A total of 306 patients with both pre- and post-ablation serum creatinine measurements available were included. Baseline eGFRs for Stages G1, G2, and G3 patients were 103.5 ± 12.9 (n = 82), 74.7 ± 8.2 (n = 184), and 52.6 ± 6.6 mL/min/1.73 m2 (n = 40), respectively. Renal function was assessed 310.8 ± 104.2 days post-ablation. Average intra-procedural contrast use was 58.4 ± 23.8 mL. There was no significant change in eGFR following CBA in Stage G1 patients (p = 0.10). For those with Stages G2 and G3 renal function, eGFR improved by 6.1% (4.2 mL/min/1.73 m2, p < 0.01) and 13.8% (7.2 mL/min/1.73 m2, p < 0.01), respectively. This improvement was seen regardless of the presence or absence of recurrent atrial arrhythmias. CONCLUSIONS: CBA for AF may be associated with an improvement in renal function, particularly among those with a reduced baseline eGFR despite recurrence of atrial arrhythmias and intra-procedural contrast use.

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.

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.

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.

A novel risk model for very late return of atrial fibrillation beyond 1 year after cryoballoon ablation: the SCALE-CryoAF score.

PURPOSE: Cryoballoon ablation (CBA) is an effective technique for pulmonary vein isolation (PVI). To date, there are no risk models to predict very late recurrence of atrial fibrillation (VLRAF) after CBA. METHODS: Retrospective analysis of a single-center database was performed. Inclusion criteria included PVI using CBA for atrial fibrillation (AF) without additional ablation targets, follow-up > 365 days, and no recurrent AF between 90 and 365 days after procedure. The primary endpoint was recurrent AF > 30 s > 12 months post-CBA. A risk model was created using clinical variables. RESULTS: Of 674 CBA performed from 2011 to 2016, 300 patients (200 male, 62.0 ± 9.9 years) met inclusion criteria. Of these, 159 (53.0%) patients had paroxysmal AF. Patients had an average of 9.5 ± 2.7 cryoballoon freezes, and no patients required additional radiofrequency ablation lesion sets. Over a follow-up of 995 ± 490 days, 77/300 (25.7%) patients exhibited VLRAF. Univariate and multivariate analyses demonstrated that Structural heart disease (1 point), Coronary artery disease (3 points), left Atrial diameter > 43 mm (1 point), Left bundle branch block (3 points), Early return of AF (4 points), and non-paroxysmal AF (3 points) were risk factors for VLRAF. Combining these variables into a risk model, SCALE-CryoAF, (min 0; max 15) predicted VLRAF with an area under the curve of 0.73. CONCLUSION: SCALE-CryoAF is the first risk model to specifically predict first recurrence of AF beyond 1 year, VLRAF, after CBA. Model discrimination demonstrates that SCALE-CryoAF predicts VLRAF after CBA significantly better than other risk models for AF recurrence.

Characterization of atrial flutter after pulmonary vein isolation by cryoballoon ablation.

PURPOSE: Pulmonary vein isolation (PVI) by cryoballoon ablation (CBA) has emerged as a commonly used technique for the treatment of atrial fibrillation. We sought to explore the incidence, risk factors for, and characterization of post-CBA-PVI atrial flutter. METHODS: We analyzed a prospective registry of patients who underwent CBA-PVI at a single institution. We included patients with more than 3 months of follow-up data and excluded those with a history of cavotricuspid isthmus (CTI) ablation. Locations of post-CBA-PVI atrial flutters were determined by analysis of intracardiac electrograms and electroanatomic maps. RESULTS: There were 556 patients included in the analysis. The mean age was 61.0 ± 10.6 years, 67.4% were male, the number of failed anti-arrhythmic medication trials was 1.2 ± 0.8, and the duration of atrial fibrillation pre-CBA was 54.3 ± 69.1 months. The 28-mm second-generation cryoballoon was used almost exclusively. Over a median follow-up time of 22.7 ± 17.9 months, 25 (4.5%) patients developed post-CBA-PVI atrial flutter after the 3-month blanking period. Of those 25 patients, 15 (60%) underwent subsequent ablation to eliminate the atrial flutter circuit, with 60% being CTI-dependent and the remainder left-sided (p value not significant). Risk factors for the development of atrial flutter included NYHA class ≥ 2 (OR 5.02, p < 0.001), presence of baseline bundle branch block (OR 4.33, p = 0.006), and left ventricular ejection fraction < 50% (OR 3.36, p = 0.007). CONCLUSIONS: The rate of post-CBA-PVI atrial flutter is low after the blanking period even with medium-term follow-up. The origin of atrial flutter is equally divided between the right and left atria.

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.