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Background: Patients may develop atrial tachycardia (AT) after left atrial (LA) ablation of persistent atrial fibrillation (AF)., Methods: The population consisted of 101 consecutive patients (age = 64.3 ± 8.7 years, 70 males (69%), LA = 4.6 ± 0.8 cm, ejection fraction = 48.5 ± 16%) undergoing their initial procedure for persistent AF. After pulmonary vein isolation, patients either underwent posterior LA isolation (n = 50; study group) or linear ablation at the LA roof with verification of conduction block (n = 51; control group)., Results: A repeat procedure was performed in 17 (34%) and 28 (55%) patients in the study and control groups, respectively (p = 0.02). Patients in the study group were less likely to develop AT (9/50 [18%] vs. 18/51 [35%]; p = 0.02), roof-dependent (1/50 [2%] vs. 8/51 [16%]; p = 0.008), and multi-loop AT (6/50 [12%] vs. 14/51 [27%]; p = 0.03) as compared to controls. Among various factors, only posterior LA isolation was associated with a lower likelihood of AT recurrence and roof tachycardia at redo procedure (OR, 0.37; 95% CI, 0.1 to 1.00, p = 0.05, and OR, 0.1, 95% CI, 0.01 to 0.96; p < 0.05, respectively)., Conclusions: In patients with persistent AF, posterior LA isolation is associated with a lower risk of a redo procedure, roof-dependent macro-reentry, and post-ablation AT in general as compared to controls who only received roof ablation. Posterior LA isolation also obviates the need for pacing maneuvers, and may be a more definitive endpoint than linear ablation at the LA roof., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Competing Interests: Disclosures H.O. is a member of the Scientific Advisory Board of Arga Medtech. The other author reports no conflicts.

Background: Left atrial appendage exclusion (LAAE) is an effective alternative to long-term anticoagulation in patients with atrial fibrillation. Not all patients considered for LAAE undergo the procedure because of ineligibility, anatomic or medical constraints, and preference of the patient., Objective: The objective of this study was to report on the management strategies and long-term clinical outcomes of patients referred to a dedicated multidisciplinary LAAE clinic, including all who subsequently did and did not undergo LAAE., Methods: This was a retrospective analysis of prospectively acquired data from all patients referred to the comprehensive multidisciplinary LAAE clinic at the University of Michigan between 2016 and 2022. A consecutive 301 patients (age, 75 ± 8 years; 106 women) with atrial fibrillation were evaluated. LAAE was performed in 168 patients (56%) with use of the Watchman device in 146 (49%) and surgically in 22 (7%). LAAE was not performed in 133 patients (44%, no-LAAE group) because of ineligibility in 62 (21%), anatomic constraints in 23 (7%), and preference of the patient in 48 (36%). The CHA 2 DS 2 -VASc score (4.7 ± 1.5 vs 4.1 ± 1.6; P = .002) and HAS-BLED score (3.4 ± 1.0 vs 2.8 ± 1.1; P < .001) were higher in the LAAE groups., Results: Anticoagulant therapy was discontinued in 137 of 146 (94%) and 61 of 133 (61%) in the Watchman and no-LAAE groups, respectively (P < .001). During a median follow-up of 2.2 years (interquartile range, 1.2-4.0 years), in the LAAE (n = 168) and no-LAAE (n = 133) groups, respectively, 39 (23%) vs 29 (22%) deaths, 13 (8%) vs 5 (4%) thromboembolic events, and 24 (14%) vs 23 (17%) bleeding complications occurred. Continued long-term anticoagulation was not a predictor of clinical outcomes., Conclusion: After a comprehensive evaluation in a multidisciplinary clinic, ∼50% of the patients referred for LAAE did not proceed with LAAE and resumed anticoagulation., Competing Interests: Disclosures The authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Ablation of premature ventricular complexes (PVCs) originating from the parahisian area is challenging. Late gadolinium-enhanced cardiac magnetic resonance (LGE-CMR) scar may influence procedural outcomes; the impact of cardiac scar on parahisian PVCs has not been described., Objective: The objective of this study was to examine the incidence and significance of LGE-CMR scarring in patients undergoing ablation for parahisian PVCs., Methods: Consecutive patients who underwent preprocedure LGE-CMR imaging and ablation of parahisian PVCs were included. Acute and long-term outcomes were examined., Results: Forty-eight patients were included (male, n = 37; age, 66 ± 10 years; ejection fraction, 50% ± 12%; preprocedure PVC burden, 21% ± 12%). Intramural LGE-CMR scar was present in 33 of 48 (69%) patients. Cryoablation was used in 9 patients; ablation in multiple chambers was required in 28 (58%) patients. The PVC site of origin (SOO) was intramural (n = 25 patients), left ventricular (n = 5), and right ventricular (n = 18). Patients with LGE-CMR scar were more likely to have intramural PVCs (64% vs 27%; P < .04) and to require ablation in multiple cardiac chambers (58% vs 13%; P < .02). Patients with intramural scar required longer duration of ablation delivery (31 ± 20 minutes vs 17 ± 8 minutes; P < .02). Acute procedural success was 69%; PVC burden on follow-up was 6% ± 9% and similar for those with and without scar., Conclusion: Ablation of parahisian PVCs often requires mapping and ablation of multiple cardiac chambers, with an intramural SOO identified in most patients. An intramural scar was associated with an intramural SOO of the PVCs requiring more extensive ablation procedures, with similar long-term outcomes compared with those without scar., Competing Interests: Disclosures The authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Introduction: Several implantable cardioverter defibrillators (ICD) programming strategies are applied to minimize ICD therapy, especially unnecessary therapies from supraventricular arrhythmias (SVA). However, it remains unknown whether these optimal programming recommendations only benefit those with SVAs or have any detrimental effects from delayed therapy on those without SVAs. This study aims to assess the impact of SVA on the outcomes of ICD programming based on 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines., Methods: Consecutive patients who underwent ICD insertion for primary prevention were classified into four groups based on SVA status and ICD programming: (1) guideline-concordant group (GC) with SVA, (2) GC without SVA, (3) nonguideline concordant group (NGC) with SVA, and (4) NGC without SVA. Cox proportional hazard models were analyzed for freedom from ICD therapies, shock, and mortality., Results: Seven hundred and seventy-two patients (median age, 64 years) were enrolled. ICD therapies were the most frequent in NGC with SVA (24.0%), followed by NGC without SVA (19.9%), GC without SVA (11.6%), and GC with SVA (8.1%). Guideline concordant programming was associated with 68% ICD therapy reduction (HR 0.32, p = .007) and 67% ICD shock reduction (HR 0.33, p = .030) in SVA patients and 44% ICD therapy reduction in those without SVA (HR 0.56, p = .030)., Conclusion: Programming ICDs in primary prevention patients based on current guidelines reduces therapy burden without increasing mortality in both SVA and non-SVA patients. A greater magnitude of reduced ICD therapy was found in those with supraventricular arrhythmias., (© 2024 Wiley Periodicals LLC.)

Background: While ICD therapy reduction programming strategies are recommended in current multi-society guidelines, concerns remain about a possible trade-off between the benefits of ICD therapy reduction and failure to treat episodes of ventricular arrhythmias. The study is to evaluate the outcomes of primary prevention patients followed in centers with high and low concordance with the 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines., Methods: Consecutive patients with primary prevention ICD implantation from two centers between 2014 and 2016 were included. One center was classified as high guideline concordance center (HGC) with 47% (146/310) of patients with initial ICD concordant with the guidelines, and the other center was classified as low guideline concordance center (LGC) with only 1% (2/178) of patients with guideline-concordant initial ICD programming. Cox proportional hazard models were used to assess risk of first ICD therapy (ATP or shock), first ICD shock, and mortality., Results: A total of 488 patients were included (mean age, 66 ± 13 years). During a mean follow-up of 1.9 ± 0.9 years, patients followed at HGC were 63% less likely to receive any ICD therapy (adjusted HR [aHR] 0.37, 95% CI 0.42-0.99). There were no significant differences in the rate of first ICD shock (aHR 0.72, 95% CI 0.34-1.52) or mortality (aHR 1.19, 95% CI, 0.47-3.05)., Conclusions: Compared to primary prevention patients followed at LGC, primary prevention ICD patients followed at HGC received a significantly lower rate of ICD therapy, mainly from ATP reduction, without a difference in mortality during follow-up., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: Incidental left atrial appendage (LAA) isolation may occur during radiofrequency ablation of persistent atrial fibrillation (AF). The study aims to describe the mechanisms and long-term thromboembolic risk related to incidental LAA isolation., Methods: Patients who experienced incidental LAA isolation after AF ablation were included. Culprit sites where ablation resulted in LAA isolation were identified. Thromboembolic risk despite oral anticoagulation (OAC) was compared to that in a propensity-matched control group without LAA isolation., Results: Forty-one patients with LAA isolation, and 82 matched patients without LAA isolation were included. The patient age, ejection fraction, LA diameter, and CHA 2 DS 2 -VASc score were 64 ± 11 years, 55 ± 12%, 45.0 ± 7 mm and 2.62 ± 1.5, respectively. Culprit sites included the LAA base, mitral isthmus, inferior LA, Bachmann's bundle, coronary sinus, and Marshall vein. After 4.2 ± 3.6 years follow-up, thromboembolism occurred in 7 of 41 patients (17%) with LAA isolation versus 3 of 82 patients (4%) without isolation (log rank p < .009, HR 5.14, 95% CI [1.32-19.94], p = .02). Patients with and without thromboembolism had similar CHA 2 DS 2 -VASc scores (2.65 ± 1.3 vs. 2.71 ± 0.76, p = .89). Thromboembolism occurred during noncompliance with or temporary discontinuation of OAC in four of the seven patients., Conclusions: Incidental LAA isolation may occur during ablation of atrial arrhythmias in the vicinity of, or even at sites remote from the appendage. Patients with incidental LAA isolation had higher rates of thromboembolism compared to patients without isolation. Since thromboembolism may occur despite prescription for OAC, the risks of LAA isolation must be weighed against clinical benefit and appendage occlusion devices should be considered in vulnerable patients., (© 2023 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Background: Cirrhosis has been reported as an important risk factor for death in coronavirus disease 2019 (COVID-19) disease. In this study, we aimed to investigate the effects of COVID-19 on the natural course of cirrhosis before and after starting vaccination., Methods: The cirrhosis patients in our cohort ( n : 140; median age:56; 71 female) were included in this study. The median MELD (Model For End-stage Liver Disease) score was 11 (6-25) and CCI (Charlson Comorbidity Index) score was 4 (1-11). In total, 85 had CTP (Child-Turcotte-Pugh)-A, 44 had CTP-B and 11 had CTP-C cirrhosis. The course of COVID-19 in this patient group was evaluated before and after COVID-19 vaccination., Results: Between March 2020 and January 2021, 36 of the 140 cirrhosis patients had developed COVID-19. Cirrhosis (+)/COVID-19 (+) and Cirrhosis (+)/COVID-19 (-) groups did not differ in terms of age, CCI and MELD-Na scores, or gender. There were six deaths in the Cirrhosis (+)/COVID-19 (+) group and five in the Cirrhosis (+)/COVID-19 (-) group [6/36 (16.6%) vs. 5/104 (4.8%); p : 0.03]. Patients who died were older, had higher CCI and MELD-Na scores, and lower albumin levels. Having had COVID-19 [6.45 (1.43-29.4); p : 0.015], higher MELD-Na score [1.35 (1.18-1.60); p : 0.001] and higher CCI score [1.65 (1.14-2.39); p : 0.008] were found to be independent predictors of mortality. After effective vaccination started in Turkey, only 11 of the remaining 129 patients developed COVID-19, and only one patient died, who was unvaccinated., Discussion: In our cirrhotic cohort, COVID-19 disease was associated with 16% mortality in the pre-vaccination period. COVID-19 vaccination prevents serious illness and death due to COVID-19 in cirrhotic patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Keskin, Oral, Sahin, Kav and Parlak.)

Introduction: Transseptal puncture (TSP) is routinely performed for left atrial ablation procedures. The use of a three-dimensional (3D) mapping system or intracardiac echocardiography (ICE) is useful in localizing the fossa ovalis and reducing fluoroscopy use. We aimed to compare the safety and efficacy between 3D mapping system-guided TSP and ICE-guided TSP techniques., Methods: We conducted a prospective observational study of patients undergoing TSP for left atrial catheter ablation procedures (mostly atrial fibrillation ablation). Propensity scoring was used to match patients undergoing 3D-guided TSP with patients undergoing ICE-guided TSP. Logistic regression was used to compare the clinical data, procedural data, fluoroscopy time, success rate, and complications between the groups., Results: Sixty-five patients underwent 3D-guided TSP, and 151 propensity score-matched patients underwent ICE-guided TSP. The TSP success rate was 100% in both the 3D-guided and ICE-guided groups. Median needle time was 4.00 min (interquartile range [IQR]: 2.57-5.08) in patients with 3D-guided TSP compared to 4.02 min (IQR: 2.83-6.95) in those with ICE-guided TSP (p = .22). Mean fluoroscopy time was 0.2 min (IQR: 0.1-0.4) in patients with 3D-guided TSP compared to 1.2 min (IQR: 0.7-2.2) in those with ICE-guided TSP (p < .001). There were no complications related to TSP in both group., Conclusions: Three-dimensional mapping-guided TSP is as safe and effective as ICE-guided TSP without additional cost., (© 2022 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Background: Left bundle branch block (LBBB) and atrioventricular (AV) conduction abnormalities requiring permanent pacemaker (PPM) implantation occur frequently following transcatheter aortic valve replacement (TAVR). The resultant left ventricular (LV) dyssynchrony may be associated with adverse clinical events., Objectives: The purpose of this study was to assess the adverse outcomes associated with LV dyssynchrony due to high-burden right ventricular (RV) pacing or permanent LBBB following TAVR in patients with preserved left ventricular ejection fraction (LVEF)., Methods: Consecutive TAVR patients at the University of Michigan from January 2012 to June 2017 were included. Pre-existing cardiac implantable electronic device, previous LBBB, LVEF <50%, or follow-up period <1 year were excluded. The primary outcome was all-cause mortality. Secondary outcomes included cardiomyopathy (defined as LVEF ≤45%), a composite endpoint of cardiomyopathy or all-cause mortality, and the change in LVEF at 1-year follow-up., Results: A total of 362 patients were analyzed (mean age 77 years). LV dyssynchrony group (n = 91 [25.1%]) included 56 permanent LBBB patients, 12 permanent LBBB patients with PPM, and 23 non-LBBB patients with PPM and high-burden RV pacing. Remaining patients served as control (n = 271 [74.9%]). After adjusted analysis, LV dyssynchrony had significantly higher all-cause mortality (adjusted hazard ratio [HR] 2.16; 95% confidence interval [CI] 1.07-4.37) and cardiomyopathy (adjusted HR 14.80; 95% CI 6.31-14.69). The LV dyssynchrony group had mean LVEF decline of 10.5% ± 10.2% compared to a small increase (0.5% ± 7.7%) in control., Conclusion: Among TAVR patients with preserved LVEF and normal AV conduction, development of postprocedural LV dyssynchrony secondary to high-burden RV pacing or permanent LBBB was associated with significantly higher risk of death and cardiomyopathy at 1-year follow-up., (Copyright © 2022. Published by Elsevier Inc.)

In this study, we aimed to evaluate the clinical features and treatments, including the use of biological disease-modifying anti-rheumatic drugs (bDMARDs) in a large cohort of pediatric and adult immunoglobulin A vasculitis (IgAV). Since data on the use of bDMARDs in IgAV are very limited, we collated the reasons for use of bDMARDs during the disease course. Patients who were enrolled in the Hacettepe University Vasculitis Research Centre (HUVAC) registry were included. In this prospective database dating from 2014, there were 436 IgAV patients classified as IgAV according to Ankara 2008 and/or American College of Rheumatology 1990 criteria. 88 adults and 330 pediatric IgAV patients were included as the main study group. Concomitant spondyloarthritis (SpA) was observed only in adult patients (10% vs 0% in children, p < 0.001). IgAV relapse was more common in adults than in children (p: 0.017). Adult patients were mostly treated with corticosteroid (p < 0.001) and conventional synthetic disease-modifying anti-rheumatic drug treatment (< 0.001), while more than half of the pediatric patients were followed up without immunosuppressive treatment. Ten (11%) adult patients used biologics. Among them, two patients used rituximab due to IgAV disease activity, three used infliximab due to SpA, three used etanercept due to SpA (one patient had a pediatric onset enthesitis-related arthritis), and two used anakinra due to recurrent familial Mediterranean fever attacks. This is the first study evaluating the use of all bDMARDs for any reason in the IgAV cohorts in the literature. None of the pediatric patients used biologics. Our data suggest biologics are mainly used for comorbid inflammatory diseases over refractory vasculitis in adult IgAV., (© 2022. The Author(s), under exclusive licence to Società Italiana di Medicina Interna (SIMI).)

One of the most helpful strategies to deal with ongoing coronavirus pandemics is to use some prudence when treating patients infected with SARS-CoV-2. We aimed to evaluate the clinical, demographic, and laboratory parameters that might have predictive value for in-hospital mortality and the need for intensive care and build a model based on them. This study was a prospective, observational, single-center study including non-critical patients admitted to COVID-19 wards. Besides classical clinic-demographic features, basic laboratory parameters obtained on admission were tested, and then new models for each outcome were developed built on the most significant variables. Receiver operating characteristics (ROC) analyses were performed by calculating each model's probability. A total of 368 non-critical hospitalized patients were recruited, the need for ICU care was observed in 70 patients (19%). The total number of patients who died in either ICU or wards was 39 (10.6%). The first two models (based on clinical features and demographics) were developed to predict ICU and death, respectively; older age, male sex, active cancer, and low baseline saturation were noted to be independent predictors. The area under the curve values of the first two models were noted 0.878 and 0.882 (p < .001; confidence interval [CI] 95% [0.837-0.919], p < .001; CI 95% [0.844-0.922]). Following two models, the third and fourth were based on laboratory parameters with clinic-demographic features. Initial lower sodium and lower albumin levels were determined as independent factors in predicting the need for ICU care; higher blood urea nitrogen and lower albumin were independent factors in predicting in-hospital mortality. The area under the curve values of the third and fourth model was noted 0.938 and 0.929, respectively (p < .001; CI 95% [0.912-0.965], p < .001; CI 95% [0.895-962]). By integrating the widely available blood tests results with simple clinic demographic data, non-critical patients can be stratified according to their risk level. Such stratification is essential to filter the patients' non-critical underlying diseases and conditions that can obfuscate the physician's predictive capacity., (© 2022. The Author(s), under exclusive licence to Società Italiana di Medicina Interna (SIMI).)

Introduction: Monitored anesthesia care (MAC) or general anesthesia (GA) can be used during catheter ablation (CA) of atrial fibrillation (AF). However, each approach may have advantages and disadvantages with variability in operator preferences. The optimal approach has not been well established. The purpose of this study was to compare procedural efficacy, safety, clinical outcomes, and cost of CA for AF performed with MAC versus GA., Methods: The study population consisted of 810 consecutive patients (mean age: 63 ± 10 years, paroxysmal AF: 48%) who underwent a first CA for AF. All patients completed a preprocedural evaluation by the anesthesiologists. Among the 810 patients, MAC was used in 534 (66%) and GA in 276 (34%). Ten patients (1.5%) had to convert to GA during the CA., Results: Although the total anesthesia care was longer with GA particularly in patients with persistent AF, CA was shorter by 5 min with GA than MAC (p < 0.01). Prevalence of perioperative complications was similar between the two groups (4% vs. 4%, p = 0.89). There was no atrioesophageal fistula with either approach. GA was associated with a small, ~7% increase in total charges due to longer anesthesia care. During 43 ± 17 months of follow-up after a single ablation procedure, 271/534 patients (51%) in the MAC and 129/276 (47%) patients in the GA groups were in sinus rhythm without concomitant antiarrhythmic drug therapy (p = 0.28)., Conclusion: With the participation of an anesthesiologist, and proper preoperative assessment, CA of AF using GA or MAC has similar efficacy and safety., (© 2022 The Authors. Journal of Cardiovascular Electrophysiology published by Wiley Periodicals LLC.)

Purpose: We aim to describe the long-term safety and efficacy of catheter ablation (CA) in young patients (<30 years) with atrial fibrillation (AF)., Methods: This was a retrospective study of patients aged 18-30 who underwent CA for AF, and clinical characteristics and long-term outcomes are reported. Survival analyses were performed between the study group and a propensity-matched older cohort (>30 years, mean age: 58±10 years)., Results: From January 2000 to January 2019, a 1st CA (radiofrequency energy n=72, cryoballoon n=10), was performed in 82 patients (mean age 26±4 years, paroxysmal n=61, persistent n=14, longstanding persistent n=7), among 6336 consecutive patients with AF. During a follow-up of 5±5 years, 56% and 30% of the patients with paroxysmal and non-paroxysmal AF were arrhythmia free without antiarrhythmic drug (AAD) therapy after a single CA (P=0.02). After 1.5±0.8 CA procedures, 76% and 75% of the patients with paroxysmal AF and non-paroxysmal AF were arrhythmia free without AADs (P=0.54). Compared to a propensity-matched group of older patients, young patients were as likely to remain in sinus rhythm after CA (P=0.47), however after fewer repeat CAs (1.5±0.8 vs 1.9±0.9, P<0.009). There were no long-term adverse outcomes associated with CA., Conclusions: CA is a safe and effective treatment of AF in young patients with comparable outcomes to the older patients, however after fewer procedures., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: Cardiac resynchronization therapy (CRT) and left ventricular assist devices (LVAD) improve outcomes in heart failure patients. Early ventricular arrhythmias (VA) are common after LVAD and are associated with increased mortality. The association between left ventricular pacing (LVP) with CRT and VAs in the early post-LVAD period remains unclear., Methods: This was a retrospective study of all patients undergoing LVAD implantation from 1/2016 to 12/2019. Patients were divided into those with CRT and active LVP (CRT-LVP) immediately post-LVAD implant versus those without CRT-LVP. Implantable cardiac defibrillator electrograms were reviewed and early VAs were defined as sustained ventricular tachycardia (VT)/ventricular fibrillation occurring within 30 days of LVAD implantation., Results: Of 186 included patients (mean age 53 years, 75% male, mean body mass index 28), 72 had CRT devices, 63 of whom had LV pacing enabled after LVAD implant (CRT-LVP group). Patients with CRT-LVP were more likely to have VA in the early postoperative period (21% vs. 4%; p = .0001). All 9 patients with CRT in whom LVP was disabled had no early VA. Among those with early VA, patients with CRT-LVP were more likely to have monomorphic VT (77% vs. 40%; p = .07). In multiple logistic regression, CRT-LVP pacing remained an independent predictor of early VA after adjustment for history of VA and AF., Conclusions: Patients with CRT-LVP after LVAD implant had a higher incidence of early VA (specifically monomorphic VT). Epicardial LV pacing may be proarrhythmic in the early postoperative period after LVAD., (© 2022 Wiley Periodicals LLC.)

Background: Rapid and irregular ventricular rates (RVR) are an important consequence of atrial fibrillation (AF). Raw accelerometry data in combination with electrocardiogram (ECG) data have the potential to distinguish inappropriate from appropriate tachycardia in AF. This can allow for the development of a just-in-time intervention for clinical treatments of AF events. The objective of this study is to develop a machine learning algorithm that can distinguish episodes of AF with RVR that are associated with low levels of activity., Methods: This study involves 45 patients with persistent or paroxysmal AF. The ECG and accelerometer data were recorded continuously for up to 3 weeks. The prediction of AF episodes with RVR and low activity was achieved using a deterministic probabilistic finite-state automata (DPFA)-based approach. Rapid and irregular ventricular rate (RVR) is defined as having heart rates (HR) greater than 110 beats per minute (BPM) and high activity is defined as greater than 0.75 quantile of the activity level. The AF events were annotated using the FDA-cleared BeatLogic algorithm. Various time intervals prior to the events were used to determine the longest prediction intervals for predicting AF with RVR episodes associated with low levels of activity., Results: Among the 961 annotated AF events, 292 met the criterion for RVR episode. There were 176 and 116 episodes with low and high activity levels respectively. Out of the 961 AF episodes, 770 (80.1%) were used in the training data set and the remaining 191 intervals were held out for testing. The model was able to predict AF with RVR and low activity up to 4.5 min before the events. The mean prediction performance gradually decreased as the time to events increased. The overall Area under the ROC Curve (AUC) for the model lies within the range of 0.67-0.78., Conclusion: The DPFA algorithm can predict AF with RVR associated with low levels of activity up to 4.5 min before the onset of the event. This would enable the development of just-in-time interventions that could reduce the morbidity and mortality associated with AF and other similar arrhythmias., (© 2021. The Author(s).)

Introduction: Quinidine is an effective therapy for a subset of polymorphic ventricular tachycardia and ventricular fibrillation (VF) syndromes; however, the efficacy of quinidine in scar-related monomorphic ventricular tachycardia (MMVT) is unclear., Methods and Results: Between 2009 and 2020 a single VT referral center, a total of 23 patients with MMVT and structural heart disease (age 66.7 ± 10.9, 20 males, 15 with ischemic cardiomyopathy, mean LVEF 22.2 ± 12.3%, 9 with left ventricular assist device [LVAD]) were treated with quinidine (14 quinidine gluconate; 996 ± 321 mg, 8 quinidine sulfate; 1062 ± 588 mg). Quinidine was used in combination with other antiarrhythmics (AAD) in 19 (13 also on amiodarone). All patients previously failed >1 AAD (amiodarone 100%, mexiletine 73%, sotalol 32%, other 32%) and eight had prior ablations (median of 1.5). Quinidine was initiated in the setting of VT storm despite AADs (6), inability to tolerate other AADs (4), or recurrent VT(12). Ventricular arrhythmias recurred despite quinidine in 13 (59%) patients at a median of 26 (4-240) days after quinidine initiation. In patients with recurrent MMVT, VT cycle length increased from 359 to 434 ms (p = .02). Six (27.3%) patients remained on quinidine at 1 year with recurrence of ventricular arrhythmias in all. The following adverse effects were seen: gastrointestinal side effects (6), QT prolongation (2), rash (1), thrombocytopenia (1), neurologic side effects (1). One patient discontinued due to cost., Conclusion: Quinidine therapy has limited tolerability and long-term efficacy when used in the management of amiodarone-refractory scar-related MMVT., (© 2021 Wiley Periodicals LLC.)

Objectives: LMNA variants have been previously associated with cardiac abnormalities independent of lipodystrophy. We aimed to assess cardiac impact of familial partial lipodystrophy (FPLD) to understand the role of laminopathy in cardiac manifestations., Study Design: Retrospective cohort study., Methods: Clinical data from 122 patients (age range: 13-77, 101 females) with FPLD were analysed. Mature human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a patient with an LMNA variant were studied as proof-of-concept for future studies., Results: Subjects with LMNA variants had a higher prevalence of overall cardiac events than others. The likelihood of having an arrhythmia was significantly higher in patients with LMNA variants (OR: 3.77, 95% CI: 1.45-9.83). These patients were at higher risk for atrial fibrillation or flutter (OR: 5.78, 95% CI: 1.04-32.16). The time to the first arrhythmia was significantly shorter in the LMNA group, with a higher HR of 3.52 (95% CI: 1.34-9.27). Non-codon 482 LMNA variants were more likely to be associated with cardiac events (vs. 482 LMNA: OR: 4.74, 95% CI: 1.41-15.98 for arrhythmia; OR: 17.67, 95% CI: 2.45-127.68 for atrial fibrillation or flutter; OR: 5.71, 95% CI: 1.37-23.76 for conduction disease). LMNA mutant hiPSC-CMs showed a higher frequency of spontaneous activity and shorter action potential duration. Functional syncytia of hiPSC-CMs displayed several rhythm alterations such as early afterdepolarizations, spontaneous quiescence and spontaneous tachyarrhythmia, and significantly slower recovery in chronotropic changes induced by isoproterenol exposure., Conclusions: Our results highlight the need for vigilant cardiac monitoring in FPLD, especially in patients with LMNA variants who have an increased risk of developing cardiac arrhythmias. In addition, hiPSC-CMs can be studied to understand the basic mechanisms for the arrhythmias in patients with lipodystrophy to understand the impact of specific mutations., (© 2021 John Wiley & Sons Ltd.)

Background: Electrical isolation of the left atrial appendage (LAA) improves outcomes of patients with persistent atrial fibrillation (AF) but may increase the risk of thromboembolism., Objective: The purpose of this study was to describe a method to map and ablate appendage drivers without complete electrical isolation., Methods: One hundred thirteen patients underwent an ablation procedure for persistent AF. The procedure was performed during AF and consisted of pulmonary vein and posterior LA isolation as well as ablation of the LAA. The right atrium (RA) was targeted in patients with a right-to-left gradient in cycle length (CL). The end point of appendage ablation was CL slowing or AF termination but not complete isolation., Results: Among the 113 patients (mean age 64.6 ± 8.6 years; ejection fraction 54% ± 13%; LA diameter 46 ± 6.5 mm), radiofrequency ablation terminated AF in 51 patients (45%). RA ablation was performed in 41 patients (36%) at the index or repeat procedure. The mean AF CL in the RA appendage (RAA) was shorter than that in the LAA (160 ± 32 ms vs 186 ± 29 ms; P < .01) in these patients. The most frequent target in the RA was the RAA (CLs approaching 50-60 ms). Discontinuing radiofrequency ablation upon AF termination or conduction slowing prevented LAA isolation. After a mean follow-up of 24 ± 15 months, 89 patients (78%) remained arrhythmia-free without antiarrhythmic medications., Conclusion: An ablation strategy guided by the AF CL addresses LAA drivers without complete electrical isolation and also helps identify the RAA as a source of persistent AF., (Copyright © 2021 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Objectives: The study's goal was to compare the efficacy and safety of dofetilide (DOF) versus amiodarone (AMIO) in patients with atrial fibrillation (AF)., Background: Comparative efficacy of DOF versus AMIO in patients with AF has not been well established. In addition, proarrhythmia has been a concern with DOF therapy., Methods: Rhythm control was attempted by using DOF in 657 consecutive patients (mean age 72 ± 9 years; 35% women) with AF (n = 528) or atrial flutter and AF (n = 129) between January 2014 and December 2018., Results: DOF was successfully initiated in 573 (87%) of 657 patients, including 510 (89%) with persistent AF and 63 (11%) with paroxysmal AF. During a mean follow-up of 19 ± 7 months, sinus rhythm was maintained in 361 (63%) of the 573 DOF-treated patients. At 12 months, patients on DOF had a similar likelihood of experiencing recurrent atrial arrhythmias compared with the 2,476 consecutive patients treated with AMIO for rhythm control during the study period (37% vs. 39%; p = 0.56). The efficacy of DOF and AMIO was also similar in specific subgroups of patients, including patients >75 years of age, with a low left ventricular ejection fraction, obesity, renal insufficiency, and prior catheter ablation for AF. Among patients with atypical atrial flutter, likelihood of recurrent atrial flutter was similar between the DOF (43 of 108 [40%]) and AMIO (211 of 555 [38%]; p = 0.69) groups., Conclusions: When properly initiated and monitored, DOF has efficacy comparable to that of amiodarone for rhythm control in patients with AF., Competing Interests: Funding Support and Author Disclosures This study was funded in part by the Fischer Family Arrhythmia Research Fund. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Diabetes mellitus (DM) is a risk factor for atrial fibrillation (AF). The effect of antidiabetic medications on AF or the outcomes of catheter ablation (CA) has not been well described. We sought to determine whether metformin treatment is associated with a lower risk of atrial arrhythmias after CA in patients with DM and AF., Methods and Results: A first CA was performed in 271 consecutive patients with DM and AF (age: 65 ± 9 years, women: 34%; and paroxysmal AF: 51%). At a median of 13 months after CA (interquartile range: 6-30), 100/182 patients (55%) treated with metformin remained in sinus rhythm without antiarrhythmic drug therapy, compared with 36/89 patients (40%) not receiving metformin (p = .03). There was a significant association between metformin therapy and freedom from recurrent atrial arrhythmias after CA in multivariable Cox hazards models (hazard ratio [HR]: 0.66; ±95% confidence interval [CI]: 0.44-0.98; p = .04) that adjusted for age, sex, body mass index, AF type (paroxysmal vs. nonparoxysmal), antiarrhythmic medication, obstructive sleep apnea, chronic kidney disease, coronary artery disease, left ventricular ejection fraction, and left atrial diameter. A Cox model that also incorporated other antidiabetic agents and fasting blood glucose demonstrated a similar reduction in the risk of recurrent atrial arrhythmias with metformin treatment (HR: 0.63; ±95% CI: 0.42-0.96; p = .03)., Conclusions: In patients with DM, treatment with metformin appears to be independently associated with a significant reduction in the risk of recurrent atrial arrhythmias after CA for AF. Whether this effect is due to glycemic control or pleiotropic effects on electroanatomical mechanisms of AF remains to be determined., (© 2021 Wiley Periodicals LLC.)

Background: Lead damage is a complication caused by lead manipulation or heating damage from conventional electrocautery (EC) after cardiovascular implantable electronic device (CIED) replacement. Application of electrical plasma (PEAK PlasmaBlade) is a new technology that reportedly reduces this risk., Objectives: This study was designed to compare the effect of EC versus PEAK PlasmaBlade on lead parameters and complications after generator replacement procedures., Methods: We retrospectively studied 410 consecutive patients (840 leads) who underwent CIED replacement using EC (EC group) and 410 consecutive patients (824 leads) using PEAK PlasmaBlade (PlamaBlade group). Pacing lead impedance, incidence of lead damage, and complications were compared between both groups., Results: Lead impedance increased in 393 leads (46.8%) in the EC group versus 282 leads (34.2%) in the PlasmaBlade group (p < .01) with average percent changes of 6.7% and 4.0% (p < .01), respectively. Lead impedance decreased in 438 leads (52.1%) in the EC group versus 507 leads (61.5%) in the PlasmaBlade group (p < .01) with average percent changes of -5.7% and -7.1% (p < .01), respectively. Lead damage requiring lead revision occurred in five leads (0.6%) or after five procedures (1.2%) in the EC group compared to three leads (0.4%, p = .50) or after three procedures (0.7%, p = .48) in the PlasmaBlade group. There were no significant differences in the procedural-related complications between the EC group (nine patients, 2.2%) and the PlasmaBlade group (five patients, 1.2%, p = .28)., Conclusion: Conventional electrocautery can potentially damage lead insulations. However, this study shows that when used carefully electrocautery is as safe as the PEAK PlasmaBlade™., (© 2021 Wiley Periodicals LLC.)

Background: Left atrial (LA) remodeling is associated with structural, electric, and metabolic LA changes. Integrated evaluation of these features in vivo is lacking., Methods: Patients undergoing 18 F-fluorodeoxyglucose (FDG) PET-CT during a hyperinsulinemic-euglycemic clamp were classified into sinus rhythm (SR), paroxysmal AF (PAF), and persistent AF (PerAF). The LA was semiautomatically segmented, and global FDG uptake was quantified using standardized uptake values (SUVmax and SUVmean) in gated, attenuation-corrected images and normalized to LA blood pool activity. Regression was used to relate FDG data to AF burden and critical patient factors. Continuous variables were compared using t-tests or Mann-Whitney tests., Results: 117 patients were included (76% men, age 66.4 ± 11.0, ejection fraction (EF) 25[22-35]%) including those with SR (n = 48), PAF (n = 55), and PerAF (n = 14). Patients with any AF had increased SUVmean (2.3[1.5-2.4] vs 2.0[1.5-2.5], P = 0.006), SUVmax (4.4[2.8-6.7] vs 3.2[2.3-4.3], P < 0.001), uptake coefficient of variation (CoV) 0.28[0.22-0.40] vs 0.25[0.2-0.33], P < 0.001), and hypometabolic scar (32%[14%-53%] vs 16.5%[0%-38.5%], P = 0.01). AF burden correlated with increased SUVmean, SUVmax, CoV, and scar independent of age, gender, EF, or LA size (P < 0.03 for all)., Conclusions: LA structure and metabolism can be assessed using FDG PET/CT. Greater AF burden correlates with the increased LA metabolism and scar.

Background: Implanted defibrillators are capable of recording activity data based on company-specific proprietary algorithms. This study aimed to determine the prognostic significance of baseline and decline in device-derived activity level across different device companies in the real world., Methods: We performed a retrospective cohort study of patients (n = 280) who underwent a defibrillator implantation (Boston, Medtronic, St. Jude, and Biotronik) for primary prevention at the University of Michigan from 2014 to 2016. Graphical data obtained from device interrogations were retrospectively converted to numerical data. The activity level averaged over a month from a week postimplantation was used as baseline. Subsequent weekly average activity levels (SALs) were standardized to this baseline. SAL below 59.4% was used as a threshold to group patients. All-cause mortality and death/heart failure were the primary end-points of this study., Results: Fifty-six patients died in this study. On average, they experienced a 50% decline in SAL prior to death. Patients (n = 129) who dropped their SAL below threshold were more likely to be older, male, diabetic, and have more symptomatic heart failure. They also had a significantly increased risk of heart failure/death (hazard ratio [HR] 3.6, 95% confidence interval [95% CI] 2.3-5.8, P < .0001) or death (HR 4.2, 95% CI 2.2-7.7, P < .0001) compared to those who had sustained activity levels. Lower baseline activity level was also associated with significantly increased risk of heart failure/death and death., Conclusion: Significant decline in device-derived activity level and low baseline activity level are associated with increased mortality and heart failure in patients with an ICD for primary prevention., (© 2020 Wiley Periodicals LLC.)

Background: Atrial fibrillation (AF) is a growing health burden, and pulmonary vein isolation (PVI) using cryoballoon (CB) or radiofrequency (RF) represents an attractive therapeutic option. Sex-specific differences in the epidemiology, pathophysiology, and clinical presentation of AF and PVI are recognized., Objective: We aimed at comparing the efficacy, safety, and procedural characteristics of CB and RF in women and men undergoing a first PVI procedure., Methods: We searched for randomized controlled trials and prospective observational studies comparing CB and RF ablation with at least 1 year of follow-up. After merging individual patient data from 18 data sets, we investigated the sex-specific (procedure failure defined as recurrence of atrial arrhythmia, reablation, and reinitiation of antiarrhythmic medication), safety (periprocedural complications), and procedural characteristics of CB vs RF using Kaplan-Meier and multilevel models., Results: From the 18 studies, 4840 men and 1979 women were analyzed. An analysis stratified by sex correcting for several covariates showed a better efficacy of CB in men (hazard ratio for recurrence 0.88; 95% confidence interval 0.78-0.98, P = .02) but not in women (hazard ratio 0.98; 95% confidence interval 0.83-1.16; P = .82). For women and men, the energy source had no influence on the occurrence of at least 1 complication. For both sexes, the procedure time was significantly shorter with CB (-22.5 minutes for women and -27.1 minutes for men)., Conclusion: CB is associated with less long-term failures in men. A better understanding of AF-causal sex-specific mechanisms and refinements in CB technologies could lead to higher success rates in women., (Copyright © 2020 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

During coronavirus disease-2019 (COVID-19) pandemic, there continues to be a need to utilize cardiac catheterization and electrophysiology laboratories for emergent and urgent procedures. Per infection prevention guidelines and hospital codes, catheterization and electrophysiology laboratories are usually built as positive-pressure ventilation rooms to minimize the infection risk. However, patients with highly transmissible airborne diseases such as COVID-19 are best caredfor in negative ventilation rooms to minimize the risk of transmission. From a mechanical and engineering perspective, positive-pressure ventilation rooms cannot be readily converted to negative-pressure ventilation rooms. In this report, we describe a novel, quick, readily implantable, and resource-friendly approach on how to secure air quality in catheterization and electrophysiology laboratories by converting a positive-pressure ventilation room to a two-zone negative ventilation system to minimize the risk of transmission., (© 2020 Wiley Periodicals LLC.)

Background: Inappropriate therapy is a common adverse effect in patients with an implantable cardioverter-defibrillator (ICD) that may be prevented by appropriate programming., Objective: The purpose of this study was to assess the outcomes of device programming based on a 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and a 2019 focused update on optimal ICD programming and testing., Methods: Consecutive patients who underwent ICD insertion for primary prevention from 2014-2016 at 3 centers were included in the retrospective analysis. Patients were classified into 2 groups based on the tachycardia programming at the time of implant: guideline concordant group (GC) and non-guideline concordant group (NGC). Kaplan-Meier analysis and Cox proportional hazard models were used to estimate freedom from ICD therapy (antitachycardia pacing or shock), ICD shock, and death., Results: A total of 772 patients were included in the study (mean age 63.3 ± 13.8 years). Of this total, 258 patients (33.4%) were in the GC group and 514 patients (66.6%) were in the NGC group. During mean follow-up of 2.02 ± 0.91 years, guideline concordant programming was associated with a 53% reduction in ICD therapy (P <.01) and 50% reduction in ICD shock (P = .02). There were no significant differences in mortality (6% in GC group vs11% in NGC group; P = .22)., Conclusion: Only one-third of the studied population had an ICD device programmed in concordance with current guidelines. ICD programming based on the current guidelines was associated with a significantly lower rate of ICD therapy and shock without changes in mortality during intermediate-term follow-up., (Published by Elsevier Inc.)

Background: It is not clear if antiarrhythmic drug therapy (AAD) after catheter ablation (CA) of atrial fibrillation (AF) increases mortality., Objective: To determine whether there is an association between AAD therapy and mortality after CA of AF., Methods: There were 3624 consecutive patients with AF (mean age: 59 ± 11 years, women: 27%, paroxysmal AF: 58%). An AAD was used in 2253 patients (62%, AAD group) for a mean duration of 1.3 ± 0.8 years, during a mean follow-up of 6.7 ± 2.2 years after CA of AF. Using propensity score matching, with every 2 patients using an AAD matched to 1 patient who did not use AAD (NO-AAD group), Cox regression models were utilized to assess the association between AAD use (as a time-variable covariate) and all-cause mortality., Results: There were a total of 50 deaths (2.2%) in the AAD and 62 deaths (4.5%) in the NO-AAD groups, respectively (P = .02). At the time of death, 46 of 50 patients (92%) who died in the AAD cohort were still using an AAD (P = .21, compared to baseline use). On multivariate analysis, although the risk of death was not statistically significant between the AAD and NO-AAD cohorts, there was a trend towards mortality benefit with AAD therapy (hazard ratio [HR]: 0.66, 95% confidence interval [CI]: 0.43-1.00, P = .05), regardless of the rhythm or anticoagulation status., Conclusion: AAD use after CA of AF is not associated with an increased risk of mortality, suggesting that when carefully chosen and monitored, AADs appear to be safe after CA of AF., (Copyright © 2019 Heart Rhythm Society. All rights reserved.)

Despite intense research efforts, maintenance of sinus rhythm in patients with non-paroxysmal AF remains challenging with suboptimal outcomes. A major limitation to the success of current ablation-based treatments is that our understanding of AF pathophysiology is incomplete. Advances in imaging and mapping tools have been reported to improve ablation outcomes. However, the role of these new approaches on the clinical care of patients with AF remains to be validated and better understood before wide adoption can occur. This article reviews the current techniques of imaging and mapping that can be applied in the management of patients with non-paroxysmal AF with a focus on their relevance to catheter ablation. Future applications and opportunities for new knowledge are also discussed., Competing Interests: Disclosure: The authors have no relevant conflicts of interest to declare.

Background: Heart block requiring a pacemaker is common after self-expandable transcatheter aortic valve replacement (SE-TAVR); however, conduction abnormalities may improve over time. Optimal device management in these patients is unknown., Objective: To evaluate the long-term, natural history of conduction disturbances in patients undergoing pacemaker implantation following SE-TAVR., Methods: All patients who underwent new cardiac implantable electronic device (CIED) implantation at Michigan Medicine following SE-TAVR placement between January 1, 2012 and September 25, 2017 were identified. Electrocardiogram and device interrogation data were examined during follow-up to identify patients with recovery of conduction. Logistic regression analysis was used to compare clinical and procedural variables to predict conduction recovery., Results: Following SE-TAVR, 17.5% of patients underwent device placement for new atrioventricular (AV) block. Among 40 patients with an average follow-up time of 17.1 ± 8.1 months, 20 (50%) patients had durable recovery of AV conduction. Among 20 patients without long-term recovery, four (20%) had transient recovery. The time to transient conduction recovery was 2.2 ± 0.2 months with repeat loss of conduction at 8.2 ± 0.9 months. On multivariate analysis, larger aortic annular size (odds ratio: 0.53 [0.28-0.86]/mm, P = 0.02) predicted lack of conduction recovery., Conclusions: Half of the patients undergoing CIED placement for heart block following SE-TAVR recovered AV conduction within several months and maintained this over an extended follow-up period. Some patients demonstrated transient recovery of conduction before recurrence of conduction loss. Larger aortic annulus diameter was negatively associated with conduction recovery., (© 2019 Wiley Periodicals, Inc.)

Introduction: Atrial Fibrillation (AF) is the most common cardiac arrhythmia, presenting a significant independent risk factor for stroke and thromboembolism. With the emergence of m-Health devices, the importance of automatic detection of AF in an off-clinic setting is growing. This study demonstrates the performance of a bimodal classifier for distinguishing AF from sinus rhythm (SR) that could be used for automated detection of AF episodes., Methods: Surface recordings from a hand-held research device and standard electrocardiograms (ECG) were collected and analyzed from 68 subjects. An additional 48 subjects from the MIT-BIH Arrythmia Database were also analyzed. All ECGs were blindly reviewed by physicians independently of the bimodal algorithm analysis. The algorithm selects an artifact-free 6-s ECG segment out of a 20-s long recording and computes a spectral Frequency Dispersion Metric (FDM) and a temporal R-R interval variability (VRR) index., Results: Scatter plots of the VRR and FDM indices revealed two distinct clusters. The bimodal scattering of the indices revealed a linear classification boundary that could be employed to differentiate the SR from AF waveforms. The selected classification boundary was able to correctly differentiate all the subjects from both datasets into either SR or AF groups, except for 3 SR subjects from the MIT-BIH dataset., Conclusion: Our bimodal classification algorithm was demonstrated to successfully acquire, analyze and interpret ECGs for the presence of AF indicating its potential to support m-Health diagnosis, monitoring, and management of therapy in AF patients., (Copyright © 2018. Published by Elsevier Ltd.)

Background: The role of cryoballoon ablation (CBA) for antral pulmonary vein isolation (APVI) has not been well established in persistent atrial fibrillation (PerAF). Isolation of the left atrial posterior wall (BOX) after APVI has been suggested to improve the efficacy of radiofrequency catheter ablation (RFA) in PerAF., Objective: The purpose of this study was to compare characteristics and clinical outcomes of APVI by CBA vs APVI + BOX by contact force-guided RFA (CF-RFA) in patients with PerAF., Methods: APVI was performed in 167 consecutive patients with PerAF (mean age 64 ± 9 years; left atrial diameter 46 ± 6 mm) using CBA (n = 90) or CF-RFA (n = 77). After APVI, a roofline was created in 33 of 90 patients (37%) in the CBA group and BOX was performed in all 77 patients in the CF-RFA group., Results: During 21 ± 10 months of follow-up after a single ablation procedure, 37 of 90 patients (41%) in the CBA group (APVI) and 39 of 77 (51%) in the CF-RFA group (APVI + BOX) remained in sinus rhythm without antiarrhythmic drugs (AADs) (P = .22). During repeat ablation, APVI + BOX using CF-RFA was performed in 20 of 90 patients (22%) and in 18 of 77 patients (23%) who initially underwent CBA or CF-RFA, respectively. At 19 ± 10 months after repeat ablation, sinus rhythm was maintained in 55 of 90 patients (61%) and 52 of 77 patients (68%) in the CBA and CF-RFA groups without AADs, respectively (P = .39)., Conclusion: In PerAF, an initial approach of APVI by CBA or APVI + BOX by CF-RFA has a similar efficacy of 40%-50% without AADs. After repeat ablation for APVI + BOX by CF-RFA in ∼25%, sinus rhythm is maintained in 60%-70% of patients without AADs., (Copyright © 2018 Heart Rhythm Society. All rights reserved.)

Purpose: The endpoint for radiofrequency catheter ablation (RFA) of cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL) is complete conduction block along the CTI. The purpose of this study is to evaluate the utility of the temporal relationship between the P wave and the local atrial electrograms in determining complete CTI block., Methods: RFA of CTI was performed in 125 patients (age 63 ± 11 years). During pacing from the coronary sinus (CS), the intervals from the peak of the P wave (P peak ) in lead V 1 to the second component of the local atrial electrogram (A 2 ) along the ablation line (P peak -A 2 ) and from the end of the P wave (P end ) to A 2 (P end -A 2 ) were investigated before and after complete block in the first 100 patients (training set). In the next 25 patients (validation set), P peak -A 2 and P end -A 2 intervals were prospectively assessed to determine CTI block., Results: The mean P peak -A 2 and P end -A 2 immediately before complete block were - 15±24 and - 39±23 ms compared to 49 ± 17 and 21 ± 16 ms after CTI block (P < 0.0001). P peak -A 2 ≥ 20 ms and P end -A 2 ≥ 0 ms predicted CTI block with 98% sensitivity and 95% specificity and 96% sensitivity and 100% specificity, respectively. In the validation set, the positive and negative predictive values of P peak -A 2 ≥ 20 ms or P end -A 2 ≥ 0 ms were 100 and 96%, respectively. The diagnostic accuracy was 98%., Conclusions: During pacing from the CS, the temporal relationship between the P wave in lead V 1 and A 2 is a simple and reliable indicator of complete block during RFA of CTI-AFL.

Background: There are no randomized controlled studies of the efficacy and safety of protamine to reverse anticoagulant effects of heparin after catheter ablation (CA) of atrial fibrillation (AF)., Objective: The purpose of this study was to determine the efficacy and safety of protamine to expedite vascular hemostasis and ambulation after CA of AF., Methods: CA to eliminate AF (n = 139) or left atrial flutter (n = 11) was performed in 150 patients using radiofrequency catheter ablation (n = 112) or cryoballoon ablation (n = 38). CA was performed under uninterrupted anticoagulation with warfarin in 28 patients or after skipping a single dose of a novel oral anticoagulant in 122 patients who were randomized to receive protamine (n = 77) or to the control group (n = 73). Baseline and procedural characteristics were similar between the 2 groups. Hemostasis was achieved manually once the activated clotting time returned to preprocedural values., Results: The maximum activated clotting time during CA was 359 ± 31 and 359 ± 29 seconds in the protamine and control groups, respectively (P = .91). The time to hemostasis was 123 ± 95 minutes in the protamine group and 260 ± 70 minutes in the control group (P < .001). The time to ambulation was 316 ± 80 and 480 ± 92 minutes in the protamine and control groups, respectively (P < .001). There were no differences in the rates of major or minor vascular access complications or thromboembolic events (P > .05)., Conclusion: Protamine expedites vascular hemostasis and time to ambulation by ∼3 hours after CA of AF without an increase in the risk of vascular or thromboembolic complications., (Copyright © 2018 Heart Rhythm Society. All rights reserved.)

Atrial arrhythmias, including atrial fibrillation and atrial flutter, are common in patients with pulmonary hypertension and are closely associated with clinical decompensation and poor clinical outcomes. The mechanisms of arrhythmogenesis and subsequent clinical decompensation are reviewed. Practical implications and current evidence for the management of atrial arrhythmias in patients with pulmonary hypertension are summarised., Competing Interests: Disclosure: The authors have no conflicts of interest to declare.

Introduction: Although noninferiority of cryoballoon ablation (CBA) and radiofrequency catheter ablation for antral pulmonary vein isolation (APVI) has been reported in patients with paroxysmal atrial fibrillation (PAF), it is not clear whether contact force sensing (CF-RFA) and CBA with the second-generation catheter have similar procedural costs and long-term outcomes. The objective of this study is to compare the long-term efficacy and cost implications of CBA and CF-RFA in patients with PAF., Methods and Results: A first APVI was performed in 146 consecutive patients (age: 63 ± 10 years, men: 95 [65%], left atrial diameter: 42 ± 6 mm) with PAF using CBA (71) or CF-RFA (75). Clinical outcomes and procedural costs were compared. The mean procedure time was significantly shorter with CBA than with CF-RFA (98 ± 39 vs. 158 ± 47 minutes, P < 0.0001). Despite a higher equipment cost in the CBA than the CF-RFA group, the total procedure cost was similar between the two groups (P = 0.26), primarily driven by a shorter procedure duration that resulted in a lower anesthesia cost. At 25 ± 5 months after a single ablation procedure, 51 patients (72%) in the CBA, and 55 patients (73%) in the CF-RFA groups remained free from atrial arrhythmias without antiarrhythmic drug therapy (P = 0.84)., Conclusions: The procedure duration was approximately 60 minutes shorter with CBA than CF-RFA. The procedural costs were similar with both approaches. At 2 years after a single procedure, CBA and CF-RFA have similar single-procedure efficacies of 72-73%., (© 2017 Wiley Periodicals, Inc.)

Atrial fibrillation (AF) is a common cardiac arrhythmia and a major risk factor for stroke, heart failure, and premature death. The pathogenesis of AF remains poorly understood, which contributes to the current lack of highly effective treatments. To understand the genetic variation and biology underlying AF, we undertook a genome-wide association study (GWAS) of 6,337 AF individuals and 61,607 AF-free individuals from Norway, including replication in an additional 30,679 AF individuals and 278,895 AF-free individuals. Through genotyping and dense imputation mapping from whole-genome sequencing, we tested almost nine million genetic variants across the genome and identified seven risk loci, including two novel loci. One novel locus (lead single-nucleotide variant [SNV] rs12614435; p = 6.76 × 10 -18 ) comprised intronic and several highly correlated missense variants situated in the I-, A-, and M-bands of titin, which is the largest protein in humans and responsible for the passive elasticity of heart and skeletal muscle. The other novel locus (lead SNV rs56202902; p = 1.54 × 10 -11 ) covered a large, gene-dense chromosome 1 region that has previously been linked to cardiac conduction. Pathway and functional enrichment analyses suggested that many AF-associated genetic variants act through a mechanism of impaired muscle cell differentiation and tissue formation during fetal heart development., (Copyright © 2017 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Background: The role of the ligament of Marshall (LOM) in patients with atrial fibrillation (AF) has not been well defined., Objective: The purpose of this study was to describe the role of the LOM in patients with AF and related arrhythmias., Methods: Fifty-six patients (mean age 63 ± 11 years; persistent AF in 48 [86%]; ejection fraction 0.49 ± 0.13; left atrial diameter 4.7 ± 0.6 cm) with LOM-mediated arrhythmias were included., Results: A LOM-pulmonary vein (PV) connection was present in 18 patients (32%) and was eliminated with radiofrequency (RF) ablation at the left lateral ridge or crux (n = 12), at the mitral annulus (n = 3), or with alcohol/ethanol (EtOH) ablation of the vein of Marshall (VOM; n = 3). A LOM-mediated atrial tachycardia (AT) was present in 13 patients (23%). Thirty-one patients with refractory mitral isthmus conduction were referred for potential EtOH ablation. In the 6 patients in whom VOM was injected during perimitral reentry, EtOH resulted in slowing in 3 patients and termination in 1 patient. In others, EtOH infusion resulted in complete isolation of the left-sided PVs and left atrial appendage. Repeat RF and adjunctive EtOH ablation of the VOM tended to be more effective in creating conduction block across the mitral isthmus than RF ablation alone (P = .057)., Conclusion: The LOM is responsible for a variety of arrhythmia mechanisms in patients with AF and atrial tachycardia. It may be ablated at any point along its course, at the mitral annulus, at the lateral ridge/PV antrum, and epicardially in the coronary sinus and the VOM itself. EtOH ablation of the VOM may be an adjunctive strategy in patients with refractory perimitral reentry., (Copyright © 2017. Published by Elsevier Inc.)

Competing Interests: Disclosure The authors received no payment for conducting this study. The authors report no conflicts of interest in this work.

Background: Frequent premature ventricular complexes (PVCs) have been associated with increased mortality. However, the optimal approach to the risk stratification of these patients is unclear., Objective: The purpose of this study was to prospectively assess the use of cardiac magnetic resonance imaging (MRI) and programmed ventricular stimulation to identify patients with PVCs undergoing radiofrequency ablation at risk for adverse long-term outcomes., Methods: A total of 321 consecutive patients (52 ± 15 years; 157 men [49%]; left ventricular ejection fraction 51% ± 12%) underwent PVC ablation between 2004 and 2015, preceded by cardiac MRI to assess for structural heart disease (SHD). Programmed stimulation was performed at the time of the ablation procedure. If ventricular tachycardia (VT) was induced in the presence of SHD, an implantable cardioverter-defibrillator (ICD) was implanted., Results: SHD was identified by MRI in 64 patients (20%), and sustained monomorphic VT was inducible in 15 patients (5%). Fourteen patients had both SHD and inducible VT, and received an ICD after the procedure. The primary endpoint of VT/ventricular fibrillation or death was met in 15 patients after a median 20 months of follow-up. The combination of SHD by MRI and VT inducibility conferred independently an increased risk of adverse outcome (multivariate hazard ratio 25.73, 95% confidence interval 6.74-98.20; P <.001)., Conclusion: Preablation cardiac MRI and programmed stimulation can be useful for risk stratification in patients with frequent PVCs. Patients with inducible VT in the setting of SHD may benefit from ICD implantation after ablation regardless of left ventricular ejection fraction., (Copyright © 2017 Heart Rhythm Society. All rights reserved.)