Search

Ventricular tachycardia (VT) substrate in left ventricular (LV) nonischemic cardiomyopathy (NICM) consists of fibrosis with surviving myocardium.The purpose of this study was to determine whether, in patients with LV NICM and sustained VT, reduced QRS amplitude and QRSf during sinus rhythm can identify the presence and location of abnormal septal (S-NICM) and/or free-wall (FW-NICM) VT substrate.We compared patients with NICM and VT (group 1) with electroanatomic mapping septal (S-NICM; n = 21) or free-wall (FW-NICM; n = 20) VT substrate to a 38-patient reference cohort (group 2) with cardiac magnetic resonance imaging (cMRI) and NICM but no VT referred for primary prevention implantable cardioverter-defibrillator (26 [68.4%] with late gadolinium enhancement).Group 1 had lower QRS amplitude in leads II (0.60 ± 0.22 vs 0.86 ± 0.35, P.001), aVR (0.60 ± 0.24 vs 0.75 ± 0.31, P = .002), aVF (0.48 ± 0.20 vs 0.70 ± 0.28, P.001), and VIn LV NICM, low frontal plane QRS (0.55 mV in aVF) is associated with VT substrate. Although multilead QRS fractionation is associated with the presence and location of VT substrate, it is frequently identified in patients without VT with cMRI abnormalities.

Right ventricular (RV) pacing-induced cardiomyopathy (PICM) is typically defined as left ventricular systolic dysfunction resulting from electrical and mechanical dyssynchrony caused by RV pacing. RV PICM is common, occurring in 10-20% of individuals exposed to frequent RV pacing. Multiple risk factors for PICM have been identified, including male sex, wider native and paced QRS durations, and higher RV pacing percentage, but the ability to predict which individuals will develop PICM remains modest. Biventricular and conduction system pacing, which better preserve electrical and mechanical synchrony, typically prevent the development of PICM and reverse left ventricular systolic dysfunction after PICM has occurred.

Background Interatrial septal tachycardias (IAS-ATs) following atrial fibrillation (AF) ablation or cardiac surgery are rare, and their management is challenging. Objective The purpose of this study was to investigate the electrophysiological features and outcomes associated with catheter ablation of IAS-AT. Methods We screened 338 patients undergoing catheter ablation of ATs following AF ablation or cardiac surgery. Diagnosis of IAS-AT was based on activation mapping and analysis of response to atrial overdrive pacing. Results Twenty-nine patients (9%) had IAS-AT (cycle length [CL] 311 ± 104 ms); 16 (55%) had prior AF ablation procedures (median 3; range 1–5), 3 (10%) had prior surgical maze, and 12 (41%) had prior cardiac surgery (including atrial septal defect surgical repair in 5 and left atrial myxoma resection in 1). IAS substrate abnormalities were documented in all patients. Activation mapping always demonstrated a diffuse early IAS breakout with centrifugal biatrial activation, and atrial overdrive pacing showed a good postpacing interval (equal or within 25 ms of the AT CL) only at 1 or 2 anatomically opposite IAS sites in all cases. Ablation was acutely successful in 27 patients (93%) (from only the right IAS in 2, only the left IAS in 9, both IAS sides with sequential ablation in 13, and both IAS sides with bipolar ablation in 3). After median follow-up of 15 (6–52) months, 17 patients (59%) remained free from recurrent arrhythmias. Conclusion IAS-ATs are rare and typically occur in patients with evidence of IAS substrate abnormalities and prior cardiac surgery. Catheter ablation can be challenging and may require sequential unipolar ablation or bipolar ablation.

Objectives The goal of this study was to characterize the relationship between DF, the electroanatomic mapping (EAM) substrate, and outcomes of catheter ablation of VT in NICM. Background A substantial proportion of patients with nonischemic dilated cardiomyopathy (NICM) and ventricular tachycardia (VT) do not have scar detectable by cardiac magnetic resonance late gadolinium enhancement (LGE) imaging. In these patients, the significance of diffuse fibrosis (DF) detected with T1 mapping has not been previously investigated. Methods This study included 51 patients with NICM and VT undergoing catheter ablation (median age 55 years; 77% male subjects) who had no evidence of LGE on pre-procedural cardiac magnetic resonance. Post-contrast T1 relaxation time determined on the septum was assessed as a surrogate of DF burden. The extent of endocardial low-voltage areas (LVAs) at EAM was correlated with T1 mapping data. Results Bipolar LVAs were present in 22 (43%) patients (median extent 15 cm2 [8 to 29 cm2]) and unipolar LVA in all patients (median extent 48 cm2 [26 to 120 cm2]). A significant inverse correlation was found between T1 values and both unipolar-LVA (R2 = 0.64; β = –0.85; p Conclusions In patients with NICM and no evidence of LGE undergoing catheter ablation of VT, DF estimated by using post-contrast T1 mapping correlates with the voltage abnormality at EAM and seems to affect post-ablation outcomes.

Together, heart failure and arrhythmia represent the most important cardiovascular sources of morbidity and mortality among adults with congenital heart disease (ACHDs). Although traditionally conceptualized as operating within 2 distinct clinical silos, these scenarios frequently coexist within the same individual; consequently the mechanistic, therapeutic, and prognostic overlap between them demands increased recognition. In fact, given the near ubiquity of heart failure and arrhythmia among ACHDs, there is perhaps no other arena within cardiology where this critical intersection is more frequently observed. Optimal care for ACHDs therefore requires a heightened awareness of the relevant interactions as well as the pharmacologic and interventional resources that are increasingly available to the treating cardiologist. This review explores and highlights the overlap between these 2 fields to recommend a parallel, yet interactive, multidisciplinary approach to clinical management. Congenital heart disease categories are broken down into their archetypal subtypes to highlight subtleties of the pathophysiology, evaluation, and therapeutic approach.

Background: Left ventricular (LV) scar on late gadolinium enhancement (LGE) cardiac magnetic resonance has been correlated with life-threatening arrhythmic events in patients with apparently idiopathic ventricular arrhythmias (VAs). We investigated the prognostic significance of a specific LV-LGE phenotype characterized by a ringlike pattern of fibrosis. Methods: A total of 686 patients with apparently idiopathic nonsustained VA underwent contrast-enhanced cardiac magnetic resonance. A ringlike pattern of LV scar was defined as LV subepicardial/midmyocardial LGE involving at least 3 contiguous segments in the same short-axis slice. The end point of the study was time to the composite outcome of all-cause death, resuscitated cardiac arrest because of ventricular fibrillation or hemodynamically unstable ventricular tachycardia and appropriate implantable cardioverter defibrillator therapy. Results: A total of 28 patients (4%) had a ringlike pattern of scar (group A), 78 (11%) had a non-ringlike pattern (group B), and 580 (85%) had normal cardiac magnetic resonance with no LGE (group C). Group A patients were younger compared with groups B and C (median age, 40 vs 52 vs 45 years; P, SCOPUS: ar.j, info:eu-repo/semantics/published

ObjectiveTo evaluate the prognosis of patients with ischemic stroke according to the timing of an atrial fibrillation (AF) diagnosis, we created an inception cohort of incident stroke events and compared the risk of death between patients with stroke with (1) sinus rhythm, (2) known AF (KAF), and (3) AF diagnosed after stroke (AFDAS).MethodsWe used the Penn AF Free study to create an inception cohort of patients with incident stroke. Mortality events were identified after linkage with the National Death Index through June 30, 2017. We also evaluated initiation of anticoagulants and antiplatelets across the study duration. Cox proportional hazards models evaluated associations between stroke subtypes and death.ResultsWe identified 1,489 individuals who developed an incident ischemic stroke event: 985 did not develop AF at any point during the study period, 215 had KAF before stroke, 160 had AF detected ≤6 months after stroke, and 129 had AF detected >6 months after stroke. After a median follow-up of 4.9 years (interquartile range 1.9–6.8), 686 deaths occurred. The annualized mortality rate was 8.8% in the stroke, no AF group; 12.2% in the KAF group; 15.8% in the AFDAS ≤6 months group; and 12.7% in the AFDAS >6 months group. Patients in the AFDAS ≤6 months group had the highest independent risk of all-cause mortality even after multivariable adjustment for demographics, clinical risk factors, and the use of antithrombotic therapies (hazard ratio 1.62 [1.22–2.14]). Compared to the stroke, no AF group, those with KAF had a higher mortality risk that was rendered nonsignificant after adjustment.ConclusionsThe AFDAS group had the highest risk of death, which was not explained by comorbidities or use of antithrombotic therapies.

INTRODUCTION Cryoballoon ablation (CBA) is an alternative to radiofrequency ablation (RFA) for ablation of atrial fibrillation (AF) and real-world comparisons of this strategy are lacking. As such, we sought to compare patient and periprocedural characteristics and outcomes of CBA versus RFA in the Get With the Guidelines AFIB Registry. METHODS Categorical variables were compared via the χ2 test and continuous variables were compared via the Wilcoxon rank-sum test. Adjusted analyses were performed using overlap weighting of propensity scores. RESULTS A total of 5247 (1465 CBA, 3782 RFA) ablation procedures were reported from 33 sites. Those undergoing CBA more often had paroxysmal AF (60.0% vs. 48.8%) and no prior AF ablation (87.5% vs. 73.8%). CHA2 DS2 -VASc scores were similar. Among de novo ablations, most ablations involved intracardiac echocardiography and electroanatomic mapping, but both were less common with CBA (87.3% vs. 93.9%, p

BACKGROUND Ablation of septal substrate-associated ventricular tachycardia (VT) in patients with nonischemic cardiomyopathy (NICM) is challenging. We sought to standardize the characterization of septal substrates on late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) and to examine the association of that substrate with VT exit and isthmus sites on invasive mapping. METHODS LGE-CMR was performed before electroanatomic mapping and ablation for VT in 20 NICM patients. LGE extent and distribution were quantified using myocardial signal-intensity Z scores (SI-Z). The SI-Z thresholds correlating to previously validated voltage thresholds, for abnormal tissue and dense scar were defined. RESULTS Bipolar and unipolar (electrogram) voltage amplitude measurements from the LV and RV were negatively associated with SI-Z from LGE-CMR imaging (p

Objectives This study sought to address whether technological innovations such as contact force sensing (CFS) can improve acute and long-term ablation outcomes of left ventricular papillar...

Background Twelve-lead electrocardiogram (ECG) criteria have been developed to identify idiopathic ventricular arrhythmias (VAs) from the left ventricular (LV) papillary muscles (PAPs), but accurate localization remains a challenge. Objective The purpose of this study was to develop ECG criteria for accurate localization of LV PAP VAs using lead V1 exclusively. Methods Consecutive patients undergoing mapping and ablation of VAs from the LV PAPs guided by intracardiac echocardiography from 2007 to 2018 were reviewed (study group). The QRS morphology in lead V1 was compared to patients with VAs with a "right bundle branch block" morphology from other LV locations (reference group). Patients with structural heart disease were excluded. Results One hundred eleven patients with LV PAP VAs (mean age 54 ± 16 years; 65% men) were identified, including 64 (55%) from the posteromedial PAP and 47 (42%) from the anterolateral PAP. The reference group included patients with VAs from the following LV locations: fascicles (n = 21), outflow tract (n = 36), ostium (n = 37), inferobasal segment (n = 12), and apex (5). PAP VAs showed 3 distinct QRS morphologies in lead V1 93% of the time: Rr (53%), R with a slurred downslope (29%), and RR (11%). Sensitivity, specificity, positive predictive value, and negative predictive value for the 3 morphologies combined are 93%, 98%, 98%, and 93%, respectively. The intrinsicoid deflection of PAP VAs in lead V1 was shorter than that of the reference group (63 ± 13 ms vs 79 ± 24 ms; P Conclusion VAs originating from the LV PAPs manifest unique QRS morphologies in lead V1, which can aid in rapid and accurate localization.

Background Early studies suggest that coronavirus disease 2019 (COVID-19) is associated with a high incidence of cardiac arrhythmias. SARS-CoV-2 infection may cause injury to cardiac myocytes and increase arrhythmia risk. Objective To evaluate the risk of cardiac arrest and arrhythmias including incident atrial fibrillation (AF), bradyarrhythmias, and nonsustained ventricular tachycardia (NSVT) in a large urban population hospitalized for COVID-19. We also evaluated correlations between the presence of these arrhythmias and mortality. Methods We reviewed the characteristics of all COVID-19 patients admitted to our center over a 9-week period. Throughout hospitalization, we evaluated the incidence of cardiac arrests, arrhythmias and in-patient mortality. We also used logistic regression to evaluate age, sex, race, body mass index, prevalent cardiovascular disease, diabetes, hypertension, kidney disease and ICU status as potential risk factors for each arrhythmia. Results Among 700 patients (mean age 50±18 years, 45% men, 71% African American, and 11% received ICU care), there were 9 cardiac arrests, 25 incident AF events, 9 clinically significant bradyarrhythmias, and 10 NSVTs. All cardiac arrests occurred among patients admitted to the ICU. In addition, admission to the ICU was associated with incident AF (OR 4.68 [95% CI 1.66 – 13.18]) and NSVT (OR 8.92 [95% CI 1.73 – 46.06]) after multivariable adjustment. Also, age and incident AF (OR 1.05 [95% CI 1.02 – 1.09]); and prevalent heart failure and bradyarrhythmias (OR 9.75 [95% CI 1.95 – 48.65]) were independently associated. Only cardiac arrests were associated with acute, in-hospital mortality. Conclusion Cardiac arrests and arrhythmias are likely the consequence of systemic illness and not solely the direct effects of COVID-19 infection., Graphical abstract

INTRODUCTION Functional tricuspid regurgitation (TR) remains a challenging clinical problem with poor outcomes and few effective treatments. Atrial fibrillation (AF) has been associated with functional TR. We sought to determine whether restoring sinus rhythm through catheter ablation of AF can decrease the degree of TR. METHODS AND RESULTS A retrospective cohort study of patients undergoing AF ablation between 2011 and 2017 at a single center was conducted. We included patients with at least moderate TR on echocardiogram within the year preceding ablation, who underwent repeat echocardiogram within the year following ablation. Formal quantitative analysis was performed by an experienced research echocardiographer, blinded to arrhythmia outcomes. Arrhythmia-free survival was correlated to the extent of improvement in TR. Thirty-six patients met the inclusion criteria. A baseline echocardiogram was performed 37 ± 68 days before ablation and follow-up echocardiogram 139 ± 112 days following ablation. Patients were 63.7 ± 11.1 years old with a mean CHA2 DS2 -VASc score of 2.7 ± 1.7. The degree of TR improved by at least one grade in 23 patients (64%). TR area decreased from 11.6 ± 3.4 to 7.0 ± 3.5 cm2 (p

Background Subcutaneous implantable cardioverter-defibrillators (S-ICDs) are attractive for preventing sudden cardiac death in hypertrophic cardiomyopathy (HCM) as they mitigate risks of transvenous leads in young patients. However, S-ICDs may be associated with increased inappropriate shock (IAS) in HCM patients. Objective The purpose of this study was to assess the incidence and predictors of appropriate shock and IAS in a contemporary HCM S-ICD cohort. Methods We collected electrocardiographic and clinical data from HCM patients who underwent S-ICD implantation at 4 centers. Etiologies of all S-ICD shocks were adjudicated. We used Firth penalized logistic regression to derive adjusted odds ratios (aORs) for predictors of IAS. Results Eighty-eight HCM patients received S-ICDs (81 for primary and 7 for secondary prevention) with a mean follow-up of 2.7 years. Five patients (5.7%) had 9 IAS episodes (3.8 IAS per 100 patient-years) most often because of sinus tachycardia and/or T-wave oversensing. Independent predictors of IAS were higher 12-lead electrocardiographic R-wave amplitude (aOR 2.55 per 1 mV; 95% confidence interval 1.15–6.38) and abnormal T-wave inversions (aOR 0.16; 95% confidence interval 0.02–0.97). There were 2 appropriate shocks in 7 secondary prevention patients and none in 81 primary prevention patients, despite 96% meeting Enhanced American College of Cardiology/American Heart Association criteria and the mean European HCM Risk-SCD score predicting 5.7% 5-year risk. No patients had sudden death or untreated sustained ventricular arrhythmias. Conclusion In this multicenter HCM S-ICD study, IAS were rare and appropriate shocks confined to secondary prevention patients. The R-wave amplitude increased IAS risk, whereas T-wave inversions were protective. HCM primary prevention implantable cardioverter-defibrillator guidelines overestimated the risk of appropriate shocks in our cohort.

Objectives This study investigated the prevalence and prognostic significance of concealed myocardial abnormalities identified by cardiac magnetic resonance (CMR) imaging in patients with apparently idiopathic premature ventricular contractions (PVCs). Background The role of CMR imaging in patients with frequent PVCs and otherwise negative diagnostic workup is uncertain. Methods This was a multicenter, international study that included 518 patients (44 ± 15 years; 57% men) with frequent (>1,000/24 h) PVCs and negative routine diagnostic workup. Patients underwent a comprehensive CMR protocol including late gadolinium enhancement imaging for detection of necrosis and/or fibrosis. The study endpoint was a composite of sudden cardiac death, resuscitated cardiac arrest, and nonfatal episodes of ventricular fibrillation or sustained ventricular tachycardia that required appropriate implantable cardioverter-defibrillator therapy. Results Myocardial abnormalities were found in 85 (16%) patients. Male gender (odds ratio [OR]: 4.28; 95% confidence interval [CI]: 2.06 to 8.93; p = 0.01), family history of sudden cardiac death and/or cardiomyopathy (OR: 3.61; 95% CI: 1.33 to 9.82; p = 0.01), multifocal PVCs (OR: 11.12; 95% CI: 4.35 to 28.46; p Conclusions CMR can identify concealed myocardial abnormalities in 16% of patients with apparently idiopathic frequent PVCs. Presence of myocardial abnormalities on CMR predict worse clinical outcomes.

In patients with nonischemic cardiomyopathy (NICM) little is known about the clinical impact of catheter ablation (CA) of septal ventricular tachycardia (VT) resulting in the collateral injury of the conduction system (CICS).Ninety-five consecutive patients with NICM underwent CA of septal VT. Outcomes in patients with no baseline conduction abnormalities who developed CICS (group 1, n = 28 [29%]) were compared to patients with no CICS (group 2, n = 17 [18%]) and to patients with preexisting conduction abnormalities or biventricular pacing (group 3, n = 50 [53%]). Group-1 patients were younger, had a higher left ventricular ejection fraction and a lower prevalence of New York Heart Association III/IV class compared to group 3 while no significant differences were observed with group 2. After a median follow-up of 15 months, VT recurred in 14% of patients in group 1, 12% in group 2 (P = .94) and 32% in group 3 (P = .08) while death/transplant occurred in 14% of patients in group 1, 18% in group 2 (P = .69) and 28% in group 3 (P = .15). A worsening of left ventricular ejection fraction (LVEF) (median LVEF variation, -5%) was observed in group 1 compared to group 2 (median LVEF variation, 0%; P .01) but not group-3 patients (median LVEF variation, -4%; P = .08) with a consequent higher need for new biventricular pacing in group 1 (43%) compared to group 2 (12%; P = .03) and group 3 (16%; P .01).In patients with NICM and septal substrate, sparing the abnormal substrate harboring the conduction system provides acceptable VT control while preventing a worsening of the systolic function.

This study sought to examine clinical characteristics of procedural and long-term outcomes in patients undergoing catheter ablation (CA) of outflow tract ventricular arrhythmias (OT-VAs) over 16 years.CA is an effective treatment strategy for OT-VAs.Patients undergoing CA for OT-VAs from 1999 to 2015 were divided into 3 periods: 1999 to 2004 (early), 2005 to 2010 (middle), and 2011 to 2015 (recent). Successful ablation site (right ventricular OT, aortic cusps/left ventricular OT, or coronary venous system/epicardium), VA morphology (right bundle branch block or left bundle branch block), and acute and clinical success rates were assessed.Six hundred eighty-two patients (336 female) were included (early: n = 97; middle: n = 204; recent: n = 381). Over time there was increase in use of irrigated ablation catheters and electroanatomic mapping, and more VAs were ablated from the aortic cusp/left ventricular OT or coronary venous system/epicardium (14% vs. 45% vs. 56%; p 0.0001). Acute procedural success was achieved in 585 patients (86%) and was similar between groups (82% vs. 84% vs. 88%; p = 0.27). Clinical success was also similar between groups (86% vs. 87% vs. 88%; p = 0.94), but more patients in earlier periods required repeat ablation (18% vs. 17% vs. 9%; p = 0.02). Overall complication rate was 2% (similar between groups).Over a 16-year period there was an increase in patients undergoing CA for OT-VTs, with more ablations performed at non-right ventricular outflow tract locations using electroanatomic mapping and irrigated-tip catheters. Over time, single procedure success has improved and complications have remained limited.

Objectives This study sought to evaluate the prevalence, mapping features, and ablation outcomes of non–scar-related ventricular tachycardia (NonScar-VT) and Purkinje-related VT (Purkinje-VT) in patients with structural heart disease. Background VT in structural heart disease is typically associated with scar-related myocardial re-entry. NonScar-VTs arising from areas of normal myocardium or Purkinje-VTs originating from the conduction system are less common. Methods We retrospectively analyzed 690 patients with structural heart disease who underwent VT ablation between 2013 and 2017. Results A total of 37 (5.4%) patients (16 [43%] with ischemic cardiomyopathy, 16 [43%] with nonischemic dilated cardiomyopathy, and 5 [14%] others) demonstrated NonScar/Purkinje-VTs, which represented the clinical VT in 76% of cases. Among the 37 VTs, 31 (84%) were Purkinje-VTs (28 bundle branch re-entrant VT). The remaining 6 (16%) VTs were NonScar-VTs and included 4 idiopathic outflow tract VTs. A total of 16 patients had prior history of VT ablations: empirical scar substrate modification was performed in 6 (38%) patients and residual inducibility of VT had not been assessed in 7 (44%). In all 37 patients, the NonScar/Purkinje-VT was successfully ablated. After a median follow-up of 18 months, the targeted NonScar/Purkinje-VT did not recur in any patients, and 28 (76%) of patients were free from any recurrent VT episodes. Conclusions NonScar/Purkinje-VTs can be identified in 5.4% of patients undergoing VT ablation in the setting of structural heart disease. Careful effort to induce, characterize, and map these VTs is important because substrate-based ablation strategies would fail to eliminate these types of VT.

Objective This study sought to investigate incidence of left atrial appendage (LAA) triggers of atrial fibrillation (AF) and/or organized atrial tachycardias (OAT) in patients undergoing AF ablation and to evaluate outcomes after ablation. Background Although LAA isolation is being increasingly performed during AF ablation, the true incidence of LAA triggers for AF remains unclear. Methods All patients with LAA triggers of AF and/or OAT during AF ablation from 2001 to 2017 were included. LAA triggers were defined as atrial premature depolarizations from the LAA, which initiated sustained AF and/or OAT. Results Out of 7,129 patients undergoing AF ablation over 16 years, LAA triggers were observed in 21 (0.3%) subjects (age 60 ± 9 years; 57% males; 52% persistent AF). Twenty (95%) patients were undergoing repeat ablation. The LAA was the only nonpulmonary vein trigger in 3 patients; the remaining 18 patients had both LAA and other nonpulmonary vein triggers. LAA triggers were eliminated in all patients (focal ablation in 19 patients; LAA isolation in 2 patients). Twelve months after ablation, 47.6% remained free from recurrent arrhythmia. After overall follow-up of 5.0 ± 3.6 years (median: 3.7 years; interquartile range: 1.4 to 8.9 years), 38.1% were arrhythmia-free. All 3 patients with triggers limited to the LAA remained free of AF recurrence. One patient undergoing LAA isolation developed LAA thrombus during follow-up. Conclusions The incidence of true LAA triggers is very low (0.3%). Most patients with LAA triggers have additional nonpulmonary vein triggers, and despite elimination of LAA triggers, long-term arrhythmia recurrence rates remain high. Potential risks of empiric LAA isolation during AF ablation (especially first-time AF ablation) may outweigh benefits.

Background: The substrate for ventricular tachycardia (VT) in left ventricular (LV) nonischemic cardiomyopathy may be epicardial. We assessed the prevalence, location, endocardial electrograms, and VT ablation outcomes in LV nonischemic cardiomyopathy with isolated epicardial substrate. Methods: Forty-seven of 531 (9%) patients with LV nonischemic cardiomyopathy and VT demonstrated normal endocardial (>1.5 mV)/abnormal epicardial bipolar low-voltage area (LVA, Results: Epicardial bipolar LVA (27.3 cm 2 [interquartile range, 15.8–50.0]) localized to basal (40), mid (8), and apical (3) LV with basal inferolateral LV most common (28/47, 60%). Of 44 endocardial maps available, 40 (91%) had endocardial unipolar LVA (24.5 cm 2 [interquartile range, 9.4–68.5]) and 29 (67%) had characteristic normal amplitude endocardial split electrograms opposite the epicardial LVA. At mean of 34 months, the VT-free survival was 55% after one and 72% after multiple procedures. Greater endocardial unipolar LVA than epicardial bipolar LVA (hazard ratio, 10.66 [CI, 2.63–43.12], P =0.001) and number of inducible VTs (hazard ratio, 1.96 [CI, 1.27–3.00], P =0.002) were associated with VT recurrence. Conclusions: In patients with LV nonischemic cardiomyopathy and VT, the substrate may be confined to epicardial and commonly basal inferolateral. LV endocardial unipolar LVA and normal amplitude bipolar split electrograms identify epicardial LVA. Ablation targeting epicardial VT and substrate achieves good long-term VT-free survival. Greater endocardial unipolar than epicardial bipolar LVA and more inducible VTs predict VT recurrence.

Background: When presenting for atrial fibrillation (AF) ablation, women, compared with men, tend to have more nonpulmonary vein triggers and advanced atrial disease. Whether this informs differences in AF ablation strategy is not well described. We aimed to characterize ablation strategy and complications by sex, using the Get With The Guidelines-AF registry. Methods: From the Get With The Guidelines-AF registry ablation feature, we included patients who underwent initial AF ablation procedure between January 7, 2016, and December 27, 2019. Patients were stratified based on AF type (paroxysmal versus nonparoxysmal) and sex. We compared patient demographics, ablation strategy, and complications by sex. Results: Among 5356 patients from 31 sites who underwent AF ablation, 1969 were women (36.8%). Women, compared with men, were older (66.8±9.6 versus 63.4±10.6, P P P =0.0002; inferior mitral isthmus line: 10.2% versus 7.0%, P =0.01; floor line: 46.1% versus 40.6%, P =0.02) than in men. In multivariable analysis, the association between patient sex and complications from ablation was not statistically significant. Conclusions: In this US wide AF ablation quality improvement registry, women with nonparoxysmal AF were more likely to receive adjunctive lesion sets compared with men. These findings suggest that patient sex may inform ablation strategy in ways that may not be strongly supported by evidence and emphasize the need to clarify optimal ablation strategies by sex.

Background It remains unclear whether additional left atrial posterior wall isolation (LAPWI) beyond pulmonary vein reisolation (PVRI) is beneficial in atrial fibrillation (AF) patients undergoing repeat ablation. Objective We sought to assess impact of LAPWI on arrhythmia outcomes in patients undergoing repeat AF ablation. Methods All AF patients that underwent repeat ablation between January 2016 and December 2018 were included. Those undergoing PVRI only served as control, whereas those undergoing LAPWI (with or without PVRI) were the study group. Primary endpoint was freedom from atrial arrhythmias (AA) off antiarrhythmic drugs (AADs) at 1 year follow-up. Secondary endpoint was freedom from AA on/off AADs at 1 year follow-up. Results One hundred ninety-six patients (61% paroxysmal AF, 39% persistent AF) participated; 93 underwent PVRI and 103 underwent LAPWI±PVRI. Patients in the LAPWI group were older, had more hypertension and persistent AF, and had lower rates of PV reconnection (52.4% vs 100%, P < .001). LAPWI was performed empirically in 79.6% and to target triggers in 20.4%. It was accomplished by linear lesions across the LA floor and roof alone in 65% and additional LAPW lesions in 35%. The primary and secondary endpoints were similar between patients undergoing LAPWI and those undergoing PVRI (43.7% vs 69.9%, P = .50 and 66% vs 77.4%, P = .36, respectively). There was no difference in adverse events between the 2 groups. Conclusion LAPWI did not improve freedom from atrial arrhythmias on or off AADs at 1 year beyond PVRI in AF patients undergoing repeat ablation. Differences in patient demographics and AF type may underlie the observed lack of benefit of LAPWI, and further study is warranted., Graphical abstract Outcomes of left atrial posterior wall isolation during repeat atrial fibrillation ablation

Background Low QRS amplitude (QRSa), QRS fractionation (QRSf) and longer QRS duration (QRSd) are markers of myocardial fibrosis and inflammation in non-ischemic cardiomyopathy (NICM). Objective To determine if reduction of inflammation with treatment of cardiac sarcoidosis (CS) may reverse these 12 lead ECG parameter changes. Methods 21 patients (pts) with CS and VT ablation with a positive baseline positron emission tomographic (PET 1) scan were studied. All pts received prednisone ≥40 mg for 4 to 8 weeks followed by a taper and maintenance with methotrexate ± low-dose prednisone, Results Pts in PET2(+) vs PET2(−) groups has similar gender (men 89% vs 100%, p=0.42), age (57±8 vs 56±10 years, p=0.8) and LV ejection fraction (41±11 vs 46±11, p=0.31). Baseline 12-lead ECGs showed similar QRSd, ≥2QRSf contiguous leads and QRSa for PET2(+) vs PET2(−); P all >0.15 (Table 1). At 1 yr there was a lower prevalence of ≥2QRSf contiguous leads and strong trend for shorter QRS duration and larger QRSa in lead DI if PET2(−) vs PET2(+). 4 pts demonstrated loss of QRSf 2 contiguous leads and/or increase in QRSa in DI by at least 0.15 mV from baseline if PET2(−) and none if PET2(+). Conclusions In pts with CS and VT, reversal of inflammation may result in a greater QRSa and reduction in QRSf. An increase in QRSa in lead 1 by >0.15mV and/or loss of QRSf identifies a clear positive response to treatment and negative PET at 1 year. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Richard T and Angela Clark Innovation Fund in Cardiovascular Medicine, the Mark S Marchlinski EP Research and Education Fund and the Winkelman Family Fund in Cardiovascular Innovation. Table 1

Background Catheter ablation (CA) of idiopathic premature ventricular complexes (PVCs) is typically guided by both activation and pace-mapping, with ablation ideally delivered at the site of the earliest local activation. However, activation mapping requires sufficient intraprocedural quantity of PVCs. This study aimed to investigate the outcome of CA of infrequent PVCs guided exclusively by pace-mapping. Methods We retrospectively analyzed all patients undergoing CA of idiopathic PVCs between 2014 and 2017. Results Among 327 patients, 24 (7.3%) had low intraprocedural PVC burden despite isoproterenol, including two patients with zero PVCs, rendering activation mapping impractical/impossible. All 24 had a history of symptomatic PVCs. During ablation, a median of 27 (17-55) pace-maps were performed, with best median PASO score of 97 (96-98)%. A median of 12 (8.75-18.75) radiofrequency (RF) lesions were delivered with 11.4 (8.5-17.6) minutes of total RF time. Clinical success, defined as more than 80% reduction in the burden of previously frequent PVCs and/or absence of symptoms as well as any documented clinical PVCs among those with infrequent or exercise-induced PVCs, was achieved in 19 (79%) patients over 9.2 (2.0-15.0) months of follow-up. Conclusions When activation mapping cannot be performed due to inadequate intraprocedural PVC burden, detailed pace-mapping can frequently identify the precise arrhythmia site of origin, thereby guiding successful CA.

Objectives This study describes the use of septal coronary venous mapping to facilitate substrate characterization and ablation of intramural septal ventricular arrhythmia (VA). Background Intramural septal VA represents a challenge for substrate definition and catheter ablation. Methods Between 2015 and 2018, 12 patients with structural heart disease, recurrent VA, and suspected intramural septal substrate underwent a septal coronary venous procedure in which mapping was performed by advancement of a wire into the septal perforator branches of the anterior interventricular vein. A total of 5 patients with idiopathic VA were also included as control subjects to compare substrate characteristics. Results Patients were 63 ± 14 years of age, and 11 (92%) were men. Most patients with structural heart disease had nonischemic cardiomyopathy (83%). Six patients underwent ablation for premature ventricular contractions (PVC) and 6 for ventricular tachycardia. All patients had larger septal unipolar voltage abnormalities than bipolar voltage abnormalities (mean area 35.3 ± 16.8 cm2 vs. 10.7 ± 8.4 cm2, respectively; p = 0.01), Patients with idiopathic VA had normal voltage. Septal coronary venous mapping revealed low-voltage, fractionated, and multicomponent electrograms in sinus rhythm in all patients with substrate compared to that in patients with idiopathic VA (amplitude 0.9 ± 0.9 mV vs. 4.4 ± 3.7 mV, respectively; p = 0.007; and duration 147 ± 48 ms vs. 92 ± 10 ms, respectively; p = 0.03). Ablation targeted early activation, pace map match, and/or good entrainment sites from intraseptal recording. Over a mean follow-up of 339 ± 240 days, the PVC and insertable cardioverter-defibrillator therapies burden were significantly reduced (from a mean of 22 ± 11% to 4 ± 8%; p = 0.005; and a mean 5 ± 2 to 1 ± 1; p = 0.001, respectively). Most patients (80%) with idiopathic VA remained arrhythmia free. Conclusions In patients with suspected intramural septal VA, mapping of the septal coronary veins may be helpful to characterize the arrhythmia substrate, identify ablation targets, and guide endocardial ablation.

Background Ventricular tachycardia (VT) is frequently encountered in patients with repaired and unrepaired congenital heart disease (CHD), causing significant morbidity and sudden cardiac death. Data regarding underlying VT mechanisms and optimal ablation strategies in these patients remain limited. Objective To describe the electrophysiologic mechanisms, ablation strategies, and long-term outcomes in patients with CHD undergoing VT ablation. Methods Forty-eight patients (mean age 41.3 ± 13.3 years, 77.1% male) with CHD underwent a total of 57 VT ablation procedures at two centers from 2000 to 2017. Electrophysiologic and follow-up data were analyzed. Results Of the 77 different VTs induced at initial or repeat ablation, the underlying mechanism in 62 (81.0%) was due to scar-related re-entry; the remaining included four His-Purkinje system-related macrore-entry VTs and focal VTs mainly originating from the outflow tract region (8 of 11, 72.7%). VT-free survival after a single procedure was 72.9% (35 of 48) at a median follow-up of 53 months. VT-free survival after multiple procedures was 85.4% (41 of 48) at a median follow-up of 52 months. There were no major complications. Three patients died during the follow-up period from nonarrhythmic causes, including heart failure and cardiac surgery complication. Conclusion While scar-related re-entry is the most common VT mechanism in patients with CHD, importantly, nonscar-related VT may also be present. In experienced tertiary care centers, ablation of both scar-related and nonscar-related VT in patients with CHD is safe, feasible, and effective over long-term follow-up.

Background An increasing number of adults with congenital heart disease (CHD) are undergoing catheter ablation for atrial fibrillation (AF). Data on ablation strategy and outcomes in CHD are limited. Rhythm control is often believed to be of greater importance among patients with complex CHD. Objective The purpose of this study was to examine the safety and efficacy of AF ablation in adult patients with CHD. Methods A multicenter retrospective analysis was performed of CHD patients undergoing AF ablation. Clinical data were collected, including AF and CHD type, procedural data, and outcomes. Patients were divided into 3 groups (simple, moderate, and severe) based on CHD complexity, as defined by the 2014 PACES/HRS (Pediatric and Congenital Electrophysiology Society/Heart Rhythm Society) consensus statement. One-year procedural success was defined as freedom from recurrent AF, off antiarrhythmic drugs (complete) or off/on previously failed antiarrhythmic drugs (partial). Results Overall, 84 CHD patients (mean age 51.5 ± 12.1 years; 65.5% male; 45.2% with paroxysmal AF) undergoing AF ablation (51 simple, 22 moderate, 11 severe complexity) were included. Pulmonary vein isolation was performed in 80 (95.2%), of whom 30 (35.7%) underwent pulmonary vein isolation alone. Overall, complete and complete/partial freedom was achieved at 1 year in 53.1% and 71.6%, respectively, with no significant differences between those with simple, moderate, or severe complexity. There were no major complications and 7 minor complications, and 2 patients died during follow-up. Conclusion There are dramatic differences in the degree of CHD complexity among patients referred for AF ablation. When performed at experienced centers, AF ablation is safe and effective even among patients with the most complex forms of CHD.

This study sought to determine the impact of repeat catheter ablation (CA) prior to hospital discharge based on inducibility of clinical ventricular tachycardia (VT) during noninvasive programmed ventricular stimulation (NIPS).Inducibility of clinical VT during NIPS performed several days after CA identifies patients at high risk of recurrence. The impact of NIPS-guided repeat CA has not been reported.Consecutive patients with structural heart disease undergoing CA of VT followed by NIPS were studied. Clinical VT was defined by comparison with 12-lead electrocardiograms and stored implantable cardioverter-defibrillator electrograms from spontaneous VT episodes. Among those with inducible clinical VT at NIPS, VT-free survival was compared between those in whom ablation was repeated (group 1) versus those in whom ablation was not repeated (group 2) prior to hospital discharge.Among 469 patients (64 ± 12 years of age; 85% males; 60% ischemic), 216 patients (46%) underwent NIPS 3 days (interquartile range: 2 to 4 days) after CA. Clinical VT was induced in 45 patients (21%). Among those 45, CA was repeated in 11 patients (24%). There were no significant differences in baseline clinical or index CA characteristics between groups 1 and 2. Over a median 36-month follow-up, only 1 patient (9%) in group 1 experienced VT recurrence compared to 24 patients (71%) in group 2 (p 0.01). In univariate Cox regression, repeat CA guided by NIPS (hazard ratio: 0.07; 95% confidence interval: 0.01 to 0.58; p = 0.01) was the only predictor of VT-free survival.In patients with inducible clinical VT during post-ablation NIPS, repeat CA was associated with significantly lower risk of subsequent recurrence.

Background Mitral valve prolapse (MVP) is a common valve condition and has been associated with sudden cardiac death. Premature ventricular contractions (PVCs) from the papillary muscles (PMs) may play a role as triggers for ventricular fibrillation (VF) in these patients. Objectives To characterize the electrophysiological substrate and outcomes of catheter ablation in patients with MVP and PM PVCs. Methods Of 597 patients undergoing ablation of ventricular arrhythmias during the period 2012-2015, we identified 25 patients with MVP and PVCs mapped to the PMs (64% female). PVC-triggered VF was the presentation in 4 patients and a fifth patient died suddenly during follow-up. The left ventricle ejection fraction (LVEF) was 50.5% ± 11.8% and PVC burden was 24.4% ± 13.1%. A cardiac magnetic resonance imaging was performed in nine cases and areas of late gadolinium enhancement were found in four of them. A detailed LV voltage map was performed in 11 patients, three of which exhibited bipolar voltage abnormalities. Complete PVC elimination was achieved in 19 (76%) patients and a significant reduction in PVC burden was observed in two (8%). In patients in which the ablation was successful, the PVC burden decreased from 20.4% ± 10.8% to 6.3% ± 9.5% (P = 0.001). In 5/6 patients with depressed LVEF and successful ablation, the LV function improved postablation. No significant differences were identified between patients with and without VF. Conclusions PM PVCs are a source of VF in patients with MVP and can induce PVC-mediated cardiomyopathy that reverses after PVC suppression. Catheter ablation is highly successful with more than 80% PVC elimination or burden reduction.

INTRODUCTION After atrial fibrillation (AF) ablation, oral anticoagulation (OAC) is recommended if stroke risk as assessed by CHA2 DS 2 -VASc score is high. However, patients without AF are often reluctant to take daily OAC. We describe outcome using as needed nonvitamin K antagonist (NOACs) guided by pulse monitoring to detect AF following successful ablation. METHODS AND RESULTS We identified 99 patients (84% male, age 64 ± 8 years), CHA2 DS 2 -VASc score greater than or equal to 1 in men and greater than or equal to 2 in women (median 2, range 1-6), capable of pulse assessment twice daily and no AF on extended monitoring after AF ablation. All patients were instructed to start NOAC if AF >1 hour or recurrent shorter episodes. Duration of NOAC use after restart was typically 2 to 4 weeks. After 30 ± 14 months (total 244 patient-years), 22 patients (22%) transitioned to daily NOAC because of noncompliance with pulse assessment or patient preference (six patients) or because of suspected or documented AF episode(s) in 16 (16%) patients. Of the remaining 77 (78%), 14 (14%) used NOACs but did not transition back to daily use, most (10 patients) with single use (seven patients) or non-AF rhythm (three patients) documented. There was only one thromboembolic event (0.4%/yr of follow-up) in patient without AF and one mild bleeding event (epistaxis). CONCLUSION The use of as needed NOACs when AF is suspected with pulse monitoring is effective and safe to maintain low risk of stroke and bleeding after successful ablation. Transition back to daily NOAC use should be anticipated in about one quarter of patients.

Objectives This study sought to investigate the substrate, procedural strategies, safety, and outcomes of catheter ablation (CA) for ventricular tachycardia (VT) in patients with aortic valve replacement (AVR). Background VT ablation in patients with AVR is challenging, particularly when mapping and ablation in the periaortic region are necessary. Methods We identified consecutive patients with mechanical, bioprosthetic, and transcatheter AVR who underwent CA for VT refractory to antiarrhythmic drugs and analyzed VT substrate, approach to LV access, complications, and long-term outcomes. Results Overall, 29 patients (87% men, mean age 67.9 ± 9.8 years, left ventricular ejection fraction 39 ± 10%) with prior AVR (13 mechanical, 15 bioprosthetic, 1 transcatheter AVR) underwent 40 ablations from 2004 to 2016. Left-sided mapping/CA was performed in 27 patients (36 procedures). Access was retrograde aortic in 11 procedures (all bioprosthetic), transseptal in 24 (13 mechanical; 10 bioprosthetic; 1 transcatheter AVR), or transventricular septal in 1. Periaortic bipolar or unipolar scar was detected in all 24 patients in whom detailed periaortic mapping was performed. Clinical VT circuit(s) involved the periaortic region in 10 patients (34%), 2 (7%) had bundle branch re-entry VT, and 17 (59%) had substrate unrelated to AVR. There were 2 major complications (both related to vascular access). Only 2 patients (9.1%) had VT recurrence. Over median follow-up of 12.8 months, 11 patients died (none as a result of recurrent VT). Conclusions Whereas most patients undergoing CA for VT after AVR had VT from substrate unrelated to AVR, periaortic scar is universally present and bundle branch re-entry can be the VT mechanism. CA can be safely performed with excellent long-term VT elimination.

Catheter ablation of outflow tract ventricular arrhythmias (OTVAs) with the earliest activation within the coronary venous system (CVS) can be challenging. When ablation from the CVS is not feasible or ineffective, an approach from anatomically adjacent site(s) can be considered. We report the outcomes of an anatomical approach for OTVAs linked to the CVS.We retrospectively analysed 665 OTVA patients. Of these, 65 (9.8%) had the earliest activation within the CVS. In 53 (82%) cases, an anatomical approach was attempted. The targeted adjacent anatomical structure was the endocardial left ventricular outflow tract (LVOT) in 24 (45%), the left coronary cusp or the left/right cusp junction in 17 (32%) patients, and the right ventricular outflow tract (RVOT) in 12 (23%). The anatomical approach was successful in 26 (49%) patients (27% from the coronary cusps, 65% from the LVOT, and 8% from the RVOT). The difference in activation times between the earliest activation site within the CVS and the targeted site was not significantly different between the successful and unsuccessful groups (14.2 ± 11.2 ms vs. 13.2 ± 9.3 ms; P = 0.89). The anatomical distance from the earliest activation site to the targeted site was shorter for the successful group (9.7 ± 2.4 mm vs. 13.1 ± 6.5 mm; P 0.05). In particular, when the anatomical distance was12.8 mm, anatomical approach was successful in only 1/13 (8%).In patients with OTVAs linked to the CVS, an anatomical approach targeting an adjacent site can be effective, particularly when the distance between the sites is12.8 mm.

Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Winkelman family research fund. Background. The arrhythmogenic substrate in nonischemic cardiomyopathy (NICM) characteristically consists of fibrosis with surviving myocytes. We hypothesized that the substrate may be reflected on the 12-lead ECG as depolarization abnormalities (QRS fragmentation [QRSf] and J waves) during sinus rhythm in patients with VT. Methods. Phase I subjects included a retrospective cohort with NICM and VT referred for VT ablation between 2007 and 2020 who had detailed substrate mapping. Phase II subjects included a prospective reference cohort with NICM and No VT referred for primary prevention ICD between 2017 and 2019. All patients had supraventricular rhythm. 12-lead ECGs voltage and presence of QRSf/J waves were compared between phase I and phase II patients. Results. Forty-five (59.2%) patients had epicardial (EPI) VT circuits and EPI LV low voltage. Thirty-one (40.8%) had endocardial (ENDO) VT circuits and Endo LV low voltage. All 38 Phase II subjects had cardiac magnetic resonance imaging (cMRI) with 26 (68.4%) patients demonstrating late gadolinium enhancement (LGE). Lower voltage in the limb leads was present in Phase I (NICM/VT) [DI (0.63 ± 0.33 vs 0.87 ± 0.4, p = 0.002), DII (0.6 ± 0.27 vs 0.85 ± 0.36, p Conclusions. In patients with NICM and VT the presence and location of LV scarring can be predicted by depolarization abnormalities on 12-lead ECG. ECG characteristics NICM VT and EPI substrate(n = 45) NICM VT and ENDO substrate(n = 31) p value NICM No VT and LGE(n = 26) NICM No VT and No LGE(n = 12) p value QRSf in 2 contiguous leads 35 (77.7%) 23 (74.1%) p = 0.71 19 (73%) 5 (41.7%) p = 0.06 QRSf in lead DII, DIII, AVF 30 (66.6%) 21 (67.7%) p = 0.92 17 (65.4%) 5 (41.7%) p = 0.16 QRSf in lead DI, AVL, V5, V6 22 (48.9%) 11 (35.5%) p = 0.24 10 (38.5%) 3 (25%) p = 0.41 QRSf in lead V1, V2, V3, V4 10 (22.2%) 7 (22.6%) p = 0.97 9 (34.6%) 2 (16.7%) p = 0.25

This cohort study examines inpatient, outpatient, and pharmacy claims to identify use of antiarrhythmic drugs and catheter ablation among commercially insured adults with paroxysmal atrial fibrillation., Key Points Question Are race/ethnicity and socioeconomic status associated with use of a rhythm control strategy (antiarrhythmic drugs and catheter ablation), and specifically catheter ablation, among patients with paroxysmal atrial fibrillation (AF) in the United States? Findings In this cohort study of 109 221 patients with incident paroxysmal AF, Black race and lower zip code–linked median household income were associated with less use of a rhythm control strategy, and Latinx ethnicity and lower zip code–linked median household income were associated with less use of catheter ablation. Meaning Results of this study suggest that racial/ethnic and socioeconomic inequities may be present in management of paroxysmal AF in the United States., Importance In patients with paroxysmal atrial fibrillation (AF), rhythm control with either antiarrhythmic drugs (AADs) or catheter ablation has been associated with decreased symptoms, prevention of adverse remodeling, and improved cardiovascular outcomes. Adoption of advanced cardiovascular therapeutics, however, is often slower among patients from racial/ethnic minority groups and those with lower income. Objective To ascertain the cumulative rates of AAD and catheter ablation use for the management of paroxysmal AF and to investigate for the presence of inequities in AF management by evaluating the association of race/ethnicity and socioeconomic status with their use in the United States. Design, Setting, and Participants This cohort study obtained inpatient, outpatient, and pharmacy claims data from the Optum Clinformatics Data Mart between October 1, 2015, and June 30, 2019. Adult patients (aged ≥18 years) in the database with a diagnosis of incident paroxysmal AF were identified. Patients were excluded if they did not have continuous insurance enrollment for at least 1 year before and at least 6 months after study entry. Exposures Race/ethnicity and zip code–linked median household income. Main Outcomes and Measures Treatment with a rhythm control strategy, and catheter ablation specifically, among those who received rhythm control. Multivariable logistic regression models were used to assess the association of race/ethnicity and zip code–linked median household income with a rhythm control strategy (AADs or catheter ablation) vs a rate control strategy as well as with catheter ablation vs AADs among those receiving rhythm control. Results Of the 109 221 patients who met the inclusion criteria, 55 185 were men (50.5%) and 73 523 were White (67.3%), with a median (interquartile range) age of 75 (68-82) years. A total of 86 359 patients (79.1%) were treated with rate control, 19 362 patients (17.7%) with AADs, and 3500 (3.2%) with catheter ablation. Between 2016 and 2019, the cumulative percentage of patients treated with catheter ablation increased from 1.6% to 3.8%. In multivariable analyses, Black race (adjusted odds ratio [aOR], 0.89; 95% CI, 0.83-0.94; P < .001) and lower zip code–linked median household income (aOR for

Background: We have previously shown that the presence of dual muscular coronary sinus (CS) to left atrial (LA) connections, coupled with rate-dependent unidirectional block in one limb, is associated with atrial fibrillation (AF) induction. This study sought to examine whether ablation of distal CS to LA connections at a first AF ablation reduces arrhythmia recurrence during follow-up. Methods: In this single-center, randomized, controlled trial, 35 consecutive patients with drug-refractory AF undergoing first-time ablation between August 2018 and August 2019, were randomly assigned to (1) standard ablation (pulmonary vein isolation and nonpulmonary vein trigger ablation) versus (2) standard ablation plus elimination of distal CS to LA connections targeting the earliest LA activation during distal CS pacing with a deca-polar catheter placed with its proximal electrode at the ostium. Change of the local CS atrial electrogram and LA activation sequence to early activation of the LA septum or roof during distal CS pacing were the end point for CS-LA connection elimination. Results: Thirty patients completed 6 months study follow-up (15 patients in each group). Demographic characteristics including age and AF persistence were similar in both groups. After a mean follow-up of 170±22 days, there were 7 atrial arrhythmia recurrences in the standard group and 1 recurrence in the CS-LA connection elimination group (46.7% versus 6.7%, hazard ratio, 0.12, P =0.047). Conclusions: Elimination of distal CS to LA connections reduced atrial arrhythmia recurrences compared with standard pulmonary vein isolation and nonpulmonary vein trigger ablation in patients undergoing a first AF ablation procedure in a small randomized study. This strategy warrants further evaluation in a multicenter randomized trial. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03646643.

Introduction: Long-term monitoring for atrial fibrillation (AF) is recommended in patients, who have experienced a cryptogenic stroke (CS). Clinical trials have identified AF in ~30% of patients after 3 years of continuous monitoring with insertable cardiac monitors (ICMs). Hypothesis: In a real-world analysis from a large academic healthcare system, we sought to evaluate a CS population with ICMs and a) determine the yield of AF and subsequent initiation of anticoagulation; and b) identify the presence of other arrhythmias. Methods: We evaluated all CS patients who had received an ICM between October 2014 and April 2020. We manually reviewed all stored electrocardiograms that were automatically labeled as AF by the ICM and adjudicated them as either a) AF or b) other cardiac arrhythmia including premature atrial contractions (PAC), premature ventricular contractions (PVC), supraventricular tachycardia (SVT), or nonsustained ventricular tachycardia (NSVT). Results: A total of 84 CS patients with ICMs were included: 51% men, mean age 63 years, and mean CHA 2 DS 2 -VASc 4.1. Over a median follow-up duration of 15.7 months, there were 34 patients (40% of the cohort) who did not have any AF alerts. In the remaining 50 patients, there were 960 stored electrograms that were adjudicated. Only 154 recordings from 16 patients (19% of the entire cohort) were adjudicated as AF. Oral anticoagulation was initiated in all these patients with adjudicated AF. The remaining tracings, which had been automatically categorized by the ICM as AF alerts, represented 34 patients (40% of the cohort). These patients had other arrhythmias including frequent PACs or PVCs, SVT, or NSVT. Conclusions: Compared to clinical trials, our real-world assessment suggests that the yield of AF following CS is lower - approximately 20%. Our findings highlight the importance for reviewing device tracings given the high rates of false positive for AF. Further research to refine AF detection algorithms in ICMs is needed.

Background The presence of left ventricular (LV) late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR) has been correlated to life-threatening arrhythmic events in patients with apparently idiopathic ventricular arrhythmias (VAs). Aim of the present study was to investigate the prognostic significance of a specific LV-LGE phenotype characterized by a subepicardial/midmyocardial “ring-like” pattern of fibrosis. Methods Out of a total of 518 consecutive patients with apparently idiopathic VAs who underwent CMR study, 79 (15%) had evidence of LV-LGE. Of these, 23 (4%) patients had LV LGE with ring-like pattern, defined as subepicardial or midmyocardial LGE involving at least 3 contiguous segments in the same slice (group A), while 56 (11%) patients had LV LGE with no ring-like pattern (group B). The remaining 439 patients had no LGE (group C). The end-point of the study was a composite SCD, resuscitated cardiac arrest and nonfatal episodes of ventricular fibrillation or documented sustained ventricular tachycardia. Results Group A patients were more frequently males compared to groups B and C (96% vs. 79% vs. 52%; p Conclusion In patients with apparently idiopathic VAs, a nonischemic LV-LGE with a ring-like pattern at CMR is associated with a high rate of malignant arrhythmic events during follow-up. Funding Acknowledgement Type of funding source: None

Introduction Oral anticoagulation(OAC) based on estimated stroke risk is recommended following catheter ablation(CA) of atrial fibrillation(AF), regardless of the extent of arrhythmia control. However, discontinuing OAC in selected patients may be safe. We sought to evaluate a strategy of OAC discontinuation following AF ablation guided by continuous rhythm monitoring. Methods and results We prospectively studied AF ablations performed at our institution from June 2015-December 2019. Patients that had pre-existing cardiac implantable electronic devices (CIEDs) or underwent insertable cardiac monitor(ICM) implantation immediately following AF ablation were included. OAC was continued for 6 weeks following CA in all patients, following which OAC management was guided by CHA2 DS2 VaSC score and continuous rhythm monitoring results, according to a prespecified protocol. AF recurrence was defined as ≥30 seconds (CIEDs) or ≥2 minutes (ICM). We studied 196 patients (mean age 64.7±11.3 years, 66.8% male, 85.7% ICM, 14.3% CIEDs). Mean CHA2 DS2 VaSC score was 2.2±1.5. One-year AF-free survival following CA was 83% for paroxysmal AF and 63% for persistent AF patients. Over 3 years' follow-up, OAC was discontinued in 57(33.7%) patients, mean 7.4±7.1 months following ablation. Following discontinuation, OAC was restarted for AF recurrence in 9(15.8%) patients, mean 11.7±6.8 months after stopping. This discontinuation protocol led to a 21.9% reduction in overall time exposed to OAC. There were no thromboembolic or major bleeding events. Conclusion OAC can be discontinued in a significant percentage of patients following CA of AF. When guided by continuous rhythm monitoring, this practice does not unacceptably increase the risk of thromboembolic events. This article is protected by copyright. All rights reserved.

Background: Catheter ablation is an increasingly used treatment for symptomatic atrial fibrillation (AF). However, there are limited prospective, nationwide data on patient selection and procedural characteristics. This study describes patient characteristics, techniques, treatment patterns, and safety outcomes of patients undergoing AF ablation. Methods: A total of 3139 patients undergoing AF ablation between 2016 and 2018 in the Get With The Guidelines-Atrial Fibrillation registry from 24 US centers were included. Patient demographics, medical history, procedural details, and complications were abstracted. Differences between paroxysmal and patients with persistent AF were compared using Pearson χ 2 and Wilcoxon rank-sum tests. Results: Patients undergoing AF ablation were predominantly male (63.9%) and White (93.2%) with a median age of 65. Hypertension was the most common comorbidity (67.6%), and patients with persistent AF had more comorbidities than patients with paroxysmal AF. Drug refractory, paroxysmal AF was the most common ablation indication (class I, 53.6%) followed by drug refractory, persistent AF (class I, 41.8%). Radiofrequency ablation with contact force sensing was the most common ablation modality (70.5%); 23.7% of patients underwent cryoballoon ablation. Pulmonary vein isolation was performed in 94.6% of de novo ablations; the most common adjunctive lesions included left atrial roof or posterior/inferior lines, and cavotricuspid isthmus ablation. Complications were uncommon (5.1%) and were life-threatening in 0.7% of cases. Conclusions: More than 98% of AF ablations among participating sites are performed for class I or class IIA indications. Contact force-guided radiofrequency ablation is the dominant technique and pulmonary vein isolation the principal lesion set. In-hospital complications are uncommon and rarely life-threatening.

Introduction The association of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) with epicardial and surface ventricular tachycardia (VT) electrogram features, in nonischemic cardiomyopathy (NICM), is unknown. We sought to define the association of LGE and viable wall thickness with epicardial electrogram features and exit site paced QRS duration in patients with NICM. Methods A total of 19 patients (age 53.5 +/- 11.5 years) with NICM (ejection fraction 40.2 +/- 13.2%) underwent CMR before VT ablation. LGE transmurality was quantified on CMR and coregistered with 2294 endocardial and 2724 epicardial map points. Results Both bipolar and unipolar voltage were associated with transmural signal intensity on CMR. Longer electrogram duration and fractionated potentials were associated with increased LGE transmurality, but late potentials or local abnormal ventricular activity were more prevalent in nontransmural versus transmural LGE regions (p < .05). Of all critical VT sites, 19% were located adjacent to regions with LGE but normal bipolar and unipolar voltage. Exit site QRS duration was affected by LGE transmurality and intramural scar location, but not by wall thickness, at the impulse origin. Conclusions In patients with NICM and VT, LGE is associated with epicardial electrogram features and may predict critical VT sites. Additionally, exit site QRS duration is affected by LGE transmurality and intramural location at the impulse origin or exit.

Atrial fibrillation is a leading cause of ischemic stroke. Stroke risk can be reduced with oral anticoagulation. Current guidelines recommend that decisions regarding anticoagulation after ablation be based solely on preprocedural risk. Factors that favor stopping oral anticoagulationafter atrial fibrillation ablation include lower CHA2DS2-VASc score, lesser extent of atrial cardiopathy as defined by atrial size, and fibrosis and higher bleeding risk. More extensive monitoring with insertable cardiac monitors, smart devices, and frequent pulse checks provide greater sensitivity for recurrence. The authors' strategy for managing oral anticoagulation after atrial fibrillation ablation is provided.

Background Electrical posterior wall isolation (PWI) is increasingly being used for the treatment of patients with atrial fibrillation (AF). Few data exist on the durability of PWI using current technology. Objective The purpose of this study was to characterize the frequency and location of posterior wall reconnection at the time of repeat catheter ablation for AF. Methods We performed a single-center retrospective cohort study of 50 patients undergoing repeat AF ablation after previous PWI. Durability of PWI was assessed at the time of repeat ablation based on posterior wall entrance and exit block. Sites of posterior wall reconnection were characterized based on review of recorded electrical signals and electroanatomic maps. Results At the time of repeat ablation, mean age was 67 ± 10 years, 31 of 50 patients had persistent AF, and mean CHA2DS2-VASc score was 3.0 ± 1.8. Of the 50 patients, 30 had durable PWI at repeat ablation, 1.4 ± 1.6 years after the index procedure. Patients with posterior wall reconnection required repeat ablation earlier (0.9 ± 0.6 years vs1.8 ± 1.9 years from index PWI; P = .048) and were more likely to have atypical atrial flutter (55% vs 27%; P = .043). Among patients with posterior wall reconnection, the roof was the most common site of reconnection (14/20), and 12 patients had multiple regions of reconnection noted. Conclusion Posterior wall reconnection is noted in 40% of patients undergoing repeat ablation after an index PWI. The roof of the left atrium is the most common site of posterior wall reconnection.

This study sought to examine the impact of periprocedural acute kidney injury (AKI) in scar-related ventricular tachycardia (VT) patients undergoing radiofrequency catheter ablation (RFCA) on short- and long-term outcomes.The clinical significance of periprocedural AKI in patients with scar-related VT undergoing RFCA has not been previously investigated.This study included 317 consecutive patients with scar-related VT undergoing RFCA (age: 64 ± 13 years, mean left ventricular ejection fraction: 33 ± 13%, 55% ischemic cardiomyopathy). Periprocedural AKI was defined as an absolute increase in creatinine of ≥0.3 mg/dl over 48 h or an increase of1.5× the baseline values within 1 week post-procedure.Periprocedural AKI occurred in 31 patients (10%). Independent predictors of AKI included chronic kidney disease (odds ratio [OR]: 3.43; 95% confidence interval [CI]: 1.48 to 7.96; p = 0.004), atrial fibrillation (OR: 2.42; 95% CI: 1.01 to 5.78; p = 0.047), and peri-procedural acute hemodynamic decompensation (OR: 3.98; 95% CI: 1.17 to 13.52; p = 0.003). After a median follow-up of 39 months (interquartile range: 6 to 65 months), 95 patients (30%) died. Periprocedural AKI was associated with increased risk of early mortality (within 30 days; hazard ratio [HR]: 9.91; 95% CI: 2.87 to 34.22; p 0.001) and late mortality (within 1 year) (HR: 4.57; 95% CI: 2.08 to 10.05; p 0.001). After multivariable adjustment, AKI remained independently associated with increased risk of early and late mortality (HR: 4.49; 95% CI: 1.1 to 18.36; p = 0.04, and HR: 3.28; 95% CI: 1.43 to 7.49; p = 0.005, respectively).Periprocedural AKI occurs in 10% of patients undergoing RFCA of scar-related VT and is strongly associated with increased risk of early and late post-procedural mortality.