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Background Data related to electrophysiologic characteristics of atypical atrial flutter (AFL) following atrial fibrillation (AF) ablation and its prognostic value on repeat ablation success are limited. Methods We studied consecutive patients who underwent a repeat left atrial (LA) ablation procedure for either recurrent AF or atypical AFL, at least 3 months after index AF ablation, between January 2012 and July 2019. The demographics, clinical history, procedural data, complications, and 1-year arrhythmia-free survival rates were recorded for each subject after the first repeat ablation. Results A total of 336 patients were included in our study. Among these 336 patients, 102 underwent a repeat ablation procedure for atypical AFL and 234 underwent a repeat ablation procedure for recurrent AF. The mean age was 63.7 ± 10.7 years, and 72.6% of patients were men. The atypical AFL cohort had significantly higher LA diameters (4.6 vs. 4.4 cm, p = .04) and LA volume indices (LAVi; 85.1 vs. 75.4 ml/m2 , p = .03) compared to AF patients at repeat ablation. Atypical AFL patients were more likely to have had index radiofrequency (RF) ablation (as opposed to cryoballoon) than recurrent AF patients (98% vs. 81%, p = .01). Atypical AFLs were roof-dependent in 35.6% and peri-mitral in 23.8% of cases. Major complications at repeat ablation occurred in 0.9% of the total cohort. Arrhythmia-free survival at one year was significantly higher in the recurrent atypical AFL compared to the recurrent AF cohort (75.5 vs. 65.0%, p = .04). Conclusion In our series, roof-dependent flutter is the most common form of atypical atrial flutter post AF ablation. Patients developing atypical AFL after index AF ablation have greater LA dimensions than patients with recurrent AF. The success rate of first repeat ablation is significantly higher among patients with recurrent atypical AFL as compared to recurrent AF after index AF ablation.

Background: An estimated 1 million patients require cardiac implantable electronic devices (CIEDs) but go without annually. This disparity exists in low-to-middle-income nations largely owing to the cost of CIED hardware. Humanitarian reuse of CIEDs has been shown to be safe and feasible. However, recent publications have raised concern that promotion of CIED reuse may foster a CIED “black market,” to the dismay of manufacturers, regulators, and clinicians alike. Objective: To determine if unregulated CIED sales for potential human use is a real issue by investigating unregulated public online CIED sale listings in the United States of America. Methods: An observational study was undertaken over 6 months using multiple internet search engines from May 1 to November 1, 2019. We cataloged usable CIEDs (still in packaging, manufactured

Objectives This study compared clinical outcomes between an increased electrical delay in the left ventricular region (QLV)-based LV lead implantation approach (QLV arm) and anatomical imp...

A significant proportion of AF patients with advanced age are being treated in clinical practice. Cryoballoon ablation of AF, given its shorter procedure time and comparable efficacy to radiofrequency ablation, has rapidly become a commonly used tool for AF ablation. Data regarding the outcomes of cryoballoon ablation of AF in octogenarians are limited because of the exclusion of this age group in the previous studies. The authors report outcomes of 15 octogenarian AF patients undergoing index cryoballoon ablation at a single centre. The mean age of the included patients was 83 ± 3 years. In total, 13 patients (87%) presented with paroxysmal AF, and two (13%) had long-standing persistent AF. At 6 and 12 months of follow-up, freedom from AF was 80% and 70%, respectively. None of the patients suffered any procedure-related complications. Cryoballoon ablation appears to be a safe and effective approach for treating symptomatic AF refractory to antiarrhythmic drug therapy in octogenarian patients, based on outcomes in this cohort. These findings require further validation in prospective randomised studies with larger sample sizes.

A symptomatic patient with atrial fibrillation and Cheyne-Stokes respiration (CSR) was implanted with a transvenous phrenic nerve stimulation (TPNS) device—the remedē System—that is indicated for adult patients with moderate to severe central sleep apnea. Sleep recordings demonstrated that TPNS eliminated periodic breathing by activating the diaphragm and stabilizing respiratory patterns. These recordings of preprogrammed periods on versus off TPNS illustrate prompt (1) stabilization of tidal airflow, respiratory effort, and oxygenation as stimulation amplitude increased stepwise and (2) recurrence of CSR immediately after TPNS deactivated. Despite differences in respiratory patterns, minute ventilation was comparable during periods on and off TPNS. These findings suggest that diaphragmatic pacing entrains ventilation without disrupting sleep, accounting for observed improvements in periodic breathing, gas exchange, sleep architecture, and quality of life. Effective means to relieve CSR could potentially mitigate nocturnal cardiovascular stress and disease progression. CITATION: Schwartz AR, Sgambati FP, James KJ, et al. Novel phrenic nerve stimulator treats Cheyne-Stokes respiration: polysomnographic insights. J Clin Sleep Med. 2020;16(5):817–820.

Background We have previously developed an intraprocedural automatic arrhythmia‐origin localization (AAOL) system to identify idiopathic ventricular arrhythmia origins in real time using a 3‐lead ECG. The objective was to assess the localization accuracy of ventricular tachycardia (VT) exit and premature ventricular contraction (PVC) origin sites in patients with structural heart disease using the AAOL system. Methods and Results In retrospective and prospective case series studies, a total of 42 patients who underwent VT/PVC ablation in the setting of structural heart disease were recruited at 2 different centers. The AAOL system combines 120‐ms QRS integrals of 3 leads (III, V2, V6) with pace mapping to predict VT exit/PVC origin site and projects that site onto the patient‐specific electroanatomic mapping surface. VT exit/PVC origin sites were clinically identified by activation mapping and/or pace mapping. The localization error of the VT exit/PVC origin site was assessed by the distance between the clinically identified site and the estimated site. In the retrospective study of 19 patients with structural heart disease, the AAOL system achieved a mean localization accuracy of 6.5±2.6 mm for 25 induced VTs. In the prospective study with 23 patients, mean localization accuracy was 5.9±2.6 mm for 26 VT exit and PVC origin sites. There was no difference in mean localization error in epicardial sites compared with endocardial sites using the AAOL system (6.0 versus 5.8 mm, P =0.895). Conclusions The AAOL system achieved accurate localization of VT exit/PVC origin sites in patients with structural heart disease; its performance is superior to current systems, and thus, it promises to have potential clinical utility.

Background:People living with human immunodeficiency virus (HIV+) have greater risk for sudden arrhythmic death than HIV-uninfected (HIV–) individuals. HIV-associated abnormal cardiac repolarization may contribute to this risk. We investigated whether HIV serostatus is associated with ventricular repolarization lability by using the QT variability index (QTVI), defined as a log measure of QT-interval variance indexed to heart rate variance.Methods:We studied 1123 men (589 HIV+ and 534 HIV–) from MACS (Multicenter AIDS Cohort Study), using the ZioXT ambulatory electrocardiography patch. Beat-to-beat analysis of up to 4 full days of electrocardiographic data per participant was performed using an automated algorithm (median analyzed duration [quartile 1–quartile 3]: 78.3 [66.3–83.0] hours/person). QTVI was modeled using linear mixed-effects models adjusted for demographics, cardiac risk factors, and HIV-related and inflammatory biomarkers.Results:Mean (SD) age was 60.1 (11.9) years among HIV– and 54.2 (11.2) years among HIV+ participants (PConclusions:HIV+ men have greater beat-to-beat variability in QT interval (QTVI) than HIV– men, especially in the setting of HIV viremia and heightened inflammation. Among HIV+ men, higher QTVI suggests ventricular repolarization lability, which can increase susceptibility to arrhythmias, whereas lower heart rate variability signals a component of autonomic dysfunction.

Atrial flutter (AFL) is a common form of arrhythmia recurrence after atrial fibrillation (AF) ablation. We aimed to define (1) the incidence of AFL and (2) the clinical factors associated with cavo-tricuspid isthmus dependent (typical) and atypical AFL, after AF ablation. The retrospective cohort consisted of 1,029 patients that underwent initial radiofrequency AF ablation from May 2005 to December 2013 at a single academic center. Patients with missing follow-up data, history of AFL ablation, and those with undocumented AFL were excluded. Atrial volumes were measured using three-dimensional cardiac computed tomography or magnetic resonance imaging. A total of 607 patients were included in the final cohort (age 59.2 ± 10.6 years, 76.0% men, 58.7% paroxysmal AF). During a median follow-up of 845 days (interquartile range 389 to 1,597 days), 122 (20.1%) patients developed AFL. Of these, 17 had typical AFL, 98 had atypical AFL, and 7 patients had both circuits. In the multivariable Cox regression analysis, only right atrial volume index (hazard ratio [HR] 1.25 per 10 ml/m2, confidence interval [CI] 95% 1.10 to 1.42) was associated with incident typical AFL; whereas persistent AF (HR 1.59, CI 95% 1.06 to 2.40), linear lesions (HR 1.58, CI 95% 1.02 to 2.46) and left atrial volume index (HR 1.17 per 10 ml/m2, CI 95% 1.07 to 1.27) were associated with incident atypical AFL. In conclusion, noninvasive measures of right and left atrial remodeling are strongly associated with incident AFL after AF ablation. Strategies to prevent incident AFL using these measures after index ablation warrant further investigation.

BACKGROUND Left atrial appendage (LAA) closure with the Watchman device is increasingly used in patients with nonvalvular atrial fibrillation for stroke prevention. Though clinical trials have shown a similar combined risk of ischemic and hemorrhagic stroke, there is an increased risk of ischemic stroke in patients with a Watchman device compared with anticoagulation. Some ischemic strokes are related to a device-related thrombus (DRT), which may be attributable to delayed endothelialization of exposed fabric and metal. METHODS AND RESULTS Patients undergoing Watchman LAA occlusion between January 2016 and June 2018 were enrolled in a prospective registry. From this cohort, 46 patients who had both transesophageal echocardiogram (TEE) and computed tomography (CT) at 45 days follow-up were selected for this study. The degree of LAA occlusion and type of leak were assessed by CT and TEE. TEE identified no patients with a significant (>5 mm) peri-device leak, 27 (58.6%) with nonsignificant peri-device leak (

Background The sympathetic nervous system plays an important role in arrhythmogenesis in arrhythmogenic right ventricular cardiomyopathy (ARVC). Sudden cardiac death commonly occurs during exertion, and β-blockers are associated with a reduction in arrhythmia burden. Bilateral cardiac sympathetic denervation (BCSD) has been shown to reduce implantable cardioverter-defibrillator (ICD) shocks in patients with structural heart disease and refractory ventricular tachycardia (VT); however, data in ARVC are sparse. Objective The purpose of this study was to evaluate the role of BCSD in patients with ARVC and refractory VT. Methods Consecutive patients with ARVC who underwent BCSD because of refractory VT were included. Number of ICD shocks, sustained VT episodes, VT storm, and antiarrhythmic therapy were assessed and compared before and after the intervention. VT-free survival rate, death, and heart transplantation were also evaluated. Results Eight patients with ARVC (mean age 32 ± 20 years; 3 men [38%]) underwent sympathectomy for recurrent VT. All patients failed catheter ablation, and 50% had a desmosomal mutation identified. Procedural complications included neuropathic pain, paravertebral venous plexus injury, and pneumothorax. Over a mean follow-up of 1.9 ± 0.9 years, 5 patients (63%) had no VT recurrence. BCSD significantly reduced the number of ICD shocks or sustained VT compared with 1-year pre-BCSD (mean 12.6 ± 18.2 and median 6.5 [interquartile range 4.5–10.5] pre-BCSD vs 0.9 ± 1.4 and 0 [interquartile range 0–1.5] post-BCSD; P = .011). Most of the patients (88%) were on β-blocker therapy alone at the end of follow-up. One patient underwent heart transplantation because of heart failure, and no deaths occurred. Conclusion BCSD may be an effective option for patients with ARVC and refractory ventricular arrhythmia who have failed conventional treatment modalities.

RationalePatients with ischemic cardiomyopathy (ICMP) are at high risk for malignant arrhythmias, largely due to electrophysiological remodeling of the non-infarcted myocardium. The electrophysiological properties of the non-infarcted myocardium of patients with ICMP remain largely unknown.ObjectivesTo assess the pro-arrhythmic behavior of non-infarcted myocardium in ICMP patients and couple computational simulations with machine learning to establish a methodology for the development of disease-specific action potential models based on clinically measured action potential duration restitution (APDR) data.Methods and ResultsWe enrolled 22 patients undergoing left-sided ablation (10 ICMP) and compared APDRs between ICMP and structurally normal left ventricles (SNLVs). APDRs were clinically assessed with a decremental pacing protocol. Using genetic algorithms (GAs), we constructed populations of action potential models that incorporate the cohort-specific APDRs. The variability in the populations of ICMP and SNLV models was captured by clustering models based on their similarity using unsupervised machine learning. The pro-arrhythmic potential of ICMP and SNLV models was assessed in cell- and tissue-level simulations. Clinical measurements established that ICMP patients have a steeper APDR slope compared to SNLV (by 38%, p < 0.01). In cell-level simulations, APD alternans were induced in ICMP models at a longer cycle length compared to SNLV models (385–400 vs 355 ms). In tissue-level simulations, ICMP models were more susceptible for sustained functional re-entry compared to SNLV models.ConclusionMyocardial remodeling in ICMP patients is manifested as a steeper APDR compared to SNLV, which underlies the greater arrhythmogenic propensity in these patients, as demonstrated by cell- and tissue-level simulations using action potential models developed by GAs from clinical measurements. The methodology presented here captures the uncertainty inherent to GAs model development and provides a blueprint for use in future studies aimed at evaluating electrophysiological remodeling resulting from other cardiac diseases.

Background Transesophageal echocardiography (TEE) is variably performed before atrial fibrillation (AF) ablation to evaluate left atrial appendage (LAA) thrombus. We describe our experience with transitioning to the pre-ablation cardiac computed tomography (CT) approach for the assessment of LAA thrombus during the COVID-19 pandemic. Methods We studied consecutive patients undergoing AF ablation at our center. The study cohort was divided into pre- vs. post-COVID groups. The pre-COVID cohort included ablations performed during 1 year before the COVID-19 pandemic; pre-ablation TEE was used routinely to evaluate LAA thrombus in high-risk patients. Post-COVID cohort included ablations performed during the 1 year after the COVID-19 pandemic; pre-ablation CT was performed in all patients, with TEE performed only in patients with LAA thrombus by CT imaging. The demographics, clinical history, imaging, and ablation characteristics, and peri-procedural cerebrovascular events (CVE) were recorded. Results A total of 637 patients (pre-COVID n=424, post-COVID n=213) were studied. The mean age was 65.6  10.1 years in the total cohort, and the majority were men. There was a significant increase in pre-ablation CT imaging from pre to post-COVID cohort (74.8 vs. 93.9%, p=

Background: Infiltrating adipose tissue (inFAT) is a newly recognized proarrhythmic substrate for postinfarct ventricular tachycardias (VT) identifiable on contrast-enhanced computed tomography. This study presents novel digital-heart technology that incorporates inFAT from contrast-enhanced computed tomography to noninvasively predict VT ablation targets and assesses the capability of the technology by comparing its predictions with VT ablation procedure data from patients with ischemic cardiomyopathy. Methods: Digital-heart models reflecting patient-specific inFAT distributions were reconstructed from contrast-enhanced computed tomography. The digital-heart identification of fat-based ablation targeting (DIFAT) technology evaluated the rapid-pacing–induced VTs in each personalized inFAT-based substrate. DIFAT targets that render the inFAT substrate noninducible to VT, including VTs that arise postablation, were determined. DIFAT predictions were compared with corresponding clinical ablations to assess the capabilities of the technology. Results: DIFAT was developed and applied retrospectively to 29 ischemic cardiomyopathy patients with contrast-enhanced computed tomography. DIFAT ablation volumes were significantly less than the estimated clinical ablation volumes (1.87±0.35 versus 7.05±0.88 cm 3 , P Conclusions: DIFAT is a novel digital-heart technology for individualized VT ablation guidance designed to eliminate VT inducibility following initial ablation. DIFAT predictions colocalized well with clinical ablation locations but provided significantly smaller lesions. DIFAT also predicted VTs targeted in redo procedures years later. As DIFAT uses widely accessible computed tomography, its integration into clinical workflows may augment therapeutic precision and reduce redo procedures.

BACKGROUND: We previously developed an intraprocedural automated site of origin localization system to identify the origin of early left ventricular (LV) activation using 12-lead ECGs. However, it has limitations, as it could not identify the site of origin in the right ventricle (RV), and relied on acquiring a complete electroanatomic map (EAM). OBJECTIVE: The objective of this study was to present a new system, the Automatic Arrhythmia Origin Localization (AAOL) system, which utilized incomplete EAM for localization of idiopathic ventricular arrhythmia (IVA) origin on the patient-specific geometry of LV, RV and neighboring vessels. The accuracy of the system in localizing IVA source sites on cardiac structures where pace-mapping is challenging was assessed. METHODS: Twenty patients undergoing IVA catheter ablation had a 12-lead ECG recorded during clinical arrhythmia and during pacing at various locations identified on EAM geometries. The new system combined 3-lead (III, V2, V6) 120-ms QRS integrals and patient-specific EAM geometry with pace mapping to predict the site of earliest ventricular activation. The predicted site was projected onto EAM geometry. RESULTS: Twenty-three IVA origin sites were clinically identified by activation mapping and/or pace mapping (8 RV; 15 LV, including 8 from the posteromedial papillary muscle; 2 from the aortic root; and 1 from the distal coronary sinus). The new system achieved a mean localization accuracy of 3.6 mm for the 23 mapped IVAs. CONCLUSIONS: The new intraprocedural AAOL system achieved accurate localization of IVA origin in ventricles and neighbouring vessels, which could facilitate ablation procedures for patients with IVAs. Key Words: Idiopathic ventricular arrhythmias (IVA); Premature ventricular complexes (PVCs); idiopathic ventricular tachycardia (IVT); Pace mapping; Activation mapping; Radiofrequency (RF) Ablation; ECG.

Introduction: Left atrial appendage (LAA) is the primary source of clot formation that can cause stroke or transient ischemic attack (TIA) in patients with atrial fibrillation (AF). LAA closure devices have emerged as alternatives to traditional anticoagulation therapy for reducing stroke risk in AF patients. However, ~1-2% of AF patients undergoing LAA closure have subsequent stroke/TIA event. Hypothesis: The presence of a persistent low-flow zone in LA, distinct from LAA, explains why some patients have stroke/TIA events after LAA closure. Methods: We developed a personalized stroke risk prediction tool that uses patient’s CT image to perform computational fluid dynamics simulation and determine presence of low blood-flow in the LA before and after LAA closure. Low flow is quantified by the establishment of low velocity fraction (LVF) in the LA volume, and low wall shear stress fraction (LWSSF) on the surface of the LA wall. The tool was applied retrospectively on 4 AF patients who had undergone LAA closure: 2 patients with TIA 4 months after LAA closure, and 2 controls matched for age, gender, CHA2DS2-VASc score and LAA dimensions with no complications at follow-up up to 2 years. Results: Before LAA closure, TIA and control groups had similar LVF (0.07 and 0.06, respectively) and LWSSF (0.12 and 0.16, respectively). However, after LAA closure, the TIA group had smaller reductions as compared to controls in both LVF (67% vs 79%) and LWSSF (17% vs 52%). This suggests that the LA low-flow region (especially at LA wall) was not substantially reduced after LAA closure, explaining why these patients might have experienced TIA. Conclusion: This proof-of-concept study demonstrates that LAA closure might not substantially reduce low-flow zones for all AF patients, as some retain low-flow zones in LA. Our stroke prediction tool has the potential to identify patients at risk of future stroke/TIA, thus enabling personalized patient selection to increase efficacy of LAA closure devices.

Introduction: Catheter ablation (CA) for atrial fibrillation (AF) is widely performed, with a rising proportion of patients of advanced age receiving the procedure. There are limited data describing the experience of index radiofrequency (RF) vs. cryoballoon (CB) ablation for AF among elderly patients in the United States. Hypothesis: CB ablation is associated with better outcomes in elderly patients. Methods: We conducted a retrospective analysis of patients > 75 years undergoing index AF ablation between January 2001 and March 2019 at our center. Major complications and efficacy, defined as freedom from any atrial tachyarrhythmia (ATA) lasting ≥30 seconds after 1 year of follow-up, were assessed in patients with index RF vs. CB ablation. Predictors of ATA recurrence at 1year follow-up were also evaluated. Results: In our cohort of 194 patients, the mean age was 78 + 3.1 years, 58.2% were men, and 39.4% had persistent AF. The mean left atrial (LA) diameter was 4.5 + 0.7, while mean CHA2DS2-VASc score was 3.5 + 1.2. The majority (n=149, 76.8%) underwent RF ablation. The incidence of major complications, including bleeding and cardiac tamponade, was similar in the two sub-groups (RF: 2% vs. CB: 0%, p=0.63). No significant difference in success rate at 1year follow-up was found between patients receiving RF vs. CB ablation (57.7% vs. 64.4% Figure, p=0.94). In a multivariable model adjusting for the age, sex, CHA 2 DS 2 -VASc score, AF type, and index RF vs CB ablation, only LA size was associated with ATA recurrence at 1 year follow-up with each increment of 1 cm in LA size was associated with 1.6-fold greater risk of recurrence [HR=1.59, CI: 1.05-2.41, p=0.02]. Conclusion: In elderly patients undergoing index CA for AF, RF ablation was the predominant modality with similar safety and efficacy relative to CB ablation. LA size was the significant predictor of ATA recurrence at 1year independent of index ablation modality.

Introduction: Few intraprocedural localization systems have been developed to predict idiopathic ventricular arrhythmia (IVA) source sites. However, an accurate and bi-ventricular patient-specific automated site of origin localization system remains elusive. To address this issue, we have developed a new automatic arrhythmia origin localization (AAOL) system that determines the sites of earliest activation in both ventricles and provides superior accuracy. Hypothesis: We hypothesized that the AAOL system can use electroanatomic mapping (EAM) geometry and accurately localize IVA source sites on patient-specific geometry of LV, RV and neighboring vessels using 3-lead ECGs. Methods: Twenty patients undergoing IVA catheter ablation had a 12-lead ECG recorded during clinical arrhythmia and during pacing at various locations identified on EAM geometries. The AAOL system combined 3-lead (III, V2, V6) 120-ms QRS integrals and patient-specific EAM geometry with intracardiac pacing to predict the site of earliest ventricular activation. The predicted site was projected onto the EAM geometry using the EAM triangular-mesh site nearest to the tip of the predicted site. Results: Twenty-three IVA source sites were clinically identified by activation mapping and/or pace mapping (8 RV, 15 LV, including 8 from the posteromedial papillary muscle; 2 from the aortic root; and 1 from the distal coronary sinus). The new system achieved a mean localization accuracy of 3.6 mm for the 23 mapped IVAs (Figure 1D), better than that achieved by previous systems. Conclusions: The new AAOL system offers highly accurate localization of IVA source sites in both ventricles and neighboring vessels, which could facilitate ablation procedures for patients with IVAs.

Background In contrast to historical trials, the Early Treatment of Atrial Fibrillation for Stroke Prevention Trial (EAST-AFNET 4) suggests the superiority of early rhythm control over rate control in patients with recent-onset atrial fibrillation (AF). The relative contribution of timing vs improvement in AF therapeutics over time is unclear. Objective This study aimed to isolate the assessment of early intervention for AF from temporal changes in AF treatments through a secondary analysis of subjects from the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study. Methods We compared rate and rhythm control treatments in AFFIRM subjects stratified by time from their diagnosis of AF. Time-to-event analysis was performed to compare all-cause mortality, cardiovascular hospitalizations, stroke, and number of hospitalization days. Results Of the 4060 AFFIRM subjects, 2526 subjects (62.2%) had their first episode of AF within 6 months of study enrollment. Participants with "new" AF had a decreased risk of all-cause mortality (P = .001) than did those with prior AF diagnoses. Individuals previously diagnosed with AF were similar in age and demographic characteristics, but had more medical comorbidities, including myocardial infarction (P = .006), diabetes mellitus (P = .002), smoking (P = .003), and hepatic or renal comorbidities (P = .008). There were no differences in mortality, cardiovascular hospitalizations, or stroke between rate and rhythm control strategies in either AF subgroup. Conclusion AFFIRM subjects diagnosed with AF within 6 months of study enrollment showed no difference in survival, cardiovascular hospitalization, or ischemic stroke between rate and rhythm control strategies. Superiority of rhythm control strategies reported by newer AF trials may be more attributable to the refinement of AF therapies and less related to the timing of intervention.

INTRODUCTION Atrial fibrillation (AF) ablation is successful in 60%-80% of optimal candidates, with many patients requiring repeat procedures. We performed a detailed examination of electrophysiologic findings and clinical outcomes associated with first repeat AF ablations in the era of contact force-sensing radiofrequency (RF) catheters. METHODS We retrospectively studied patients who underwent their first repeat AF ablations for symptomatic, recurrent AF at our center between 2013 and 2019. All repeat ablations were performed using contact force-sensing RF catheters. Pulmonary vein (PV) reconnections at repeat ablation and freedom from atrial arrhythmia 1 year after repeat ablation were evaluated. We further assessed these findings based on AF classification at the time of presentation for repeat ablation, index RF versus cryoballoon (CB) ablation, and duration (≥3 versus

Background The effects of atrial fibrillation (AF) catheter ablation on the left atrium (LA) are poorly understood. Objectives To examine short and long-term associations of AF catheter ablation with LA function using cardiac magnetic resonance (CMR). Methods Fifty-one AF patients (mean age 56±8 years) underwent CMR at baseline, 1 day (n=17) and 11±2 months after ablation (n=38). LA phasic volumes, emptying fractions (LAEF), and longitudinal strain were measured using feature-tracking CMR. LA fibrosis was quantified using late gadolinium enhancement (LGE). Results There were no acute changes in volume, however, active, total LAEF, and peak LA strain decreased significantly compared to the baseline. During long-term follow-up, there was a decrease in maximum but not minimum LA volume (from 99±5.2ml to 89±4.7ml, p=0.009) and a decrease in total LAEF (from 43±1.8% to 39±2.0%, p=0.001). In patients with AF recurrence, LA volumes were unchanged. However, total LAEF decreased from 38±3% to 33±3%; p=0.015. Patients without AF recurrence had no changes in LA functional parameters during follow-up. The amount of LA LGE at long term follow-up was higher compared to the baseline, however was significantly less compared to immediately post procedure (37±1.9 % vs. 47±2.8%, p=0.015). A higher increase in LA LGE extent compared to the baseline was associated with a greater decrease in total LAEF (r=-0.59, p Conclusions LA function is impaired acutely following AF catheter ablation. However, long-term changes of LA function are associated positively with successful restoration of sinus rhythm and inversely with increased LA LGE. This article is protected by copyright. All rights reserved.

Introduction Advanced interatrial block (IAB) on a 12‐lead electrocardiogram (ECG) is a predictor of stroke, incident atrial fibrillation (AF), and AF recurrence after catheter ablation. The objective of this study was to determine which features of IAB structural remodeling is associated with left atrium (LA) magnetic resonance imaging structure and function. Methods/Results We included 152 consecutive patients (23% nonparoxysmal AF) who underwent preprocedural ECG and cardiac magnetic resonance (CMR) in sinus rhythm before catheter ablation of AF. IAB was defined as P‐wave duration ≥120 ms, and was considered partial if P‐wave was positive and advanced if P‐wave had a biphasic morphology in inferior leads. From cine CMR and late gadolinium enhancement, we derived LA maximum and minimum volume indices, strain, LA fibrosis, and LA dyssynchrony. A total of 77 patients (50.7% paroxysmal) had normal P‐wave, 52 (34.2%) partial IAB, and 23 (15.1%) advanced IAB. Patients with advanced IAB had significantly higher LA minimum volume index (25.7 vs 19.9 mL/m2, P = .010), more LA fibrosis (21.9% vs 13.1%, P = .020), and lower LA maximum strain rate (0.99 vs 1.18, P = .007) than those without. Advanced IAB was independently associated with LA (minimum [P = .032] and fibrosis [P = .009]). P‐wave duration was also independently associated with LA fibrosis (β = .33; P = .049) and LA mechanical dyssynchrony (β = 2.01; P = .007). Conclusion Advanced IAB is associated with larger LA volumes, lower emptying fraction, and more fibrosis. Longer P‐wave duration is also associated with more LA fibrosis and higher LA mechanical dyssynchrony. Sin financiación 2.871 JCR (2020) Q3, 79/142 Cardiac & Cardiovascular Systems 1.193 SJR (2020) Q1, 72/349 Cardiology and Cardiovascular Medicine No data IDR 2020 UEM

The purpose of this study was to evaluate the usefulness of intra-atrial dyssynchrony as a marker of underlying left atrial (LA) remodeling to predict recurrence after the first atrial fibrillation (AF) ablation.Catheter ablation for AF remains far from curative with relatively high recurrence rates. One of the causes of recurrence is poor patient selection out of a diverse patient population with different degrees of LA remodeling.We included 208 patients with a history of AF (59.4 ± 10.0 years of age; 26.0% nonparoxysmal AF) referred for catheter ablation of AF who underwent pre-ablation cardiac magnetic resonance in sinus rhythm. Clinical follow-up was 20 ± 6 months. Using tissue tracking cardiac magnetic resonance, we measured the LA longitudinal strain in each of 12 equal-length segments in 2- and 4-chamber views. We defined intra-atrial dyssynchrony as the standard deviation of the time to the peak longitudinal strain corrected by the cycle length (SD-time to peak strain [TPS], %).Patients with AF recurrence after ablation (n = 101) had significantly higher SD-TPS than those without (n = 107; 3.9% vs. 2.2%; p 0.001). Multivariable cox analysis showed that SD-TPS was associated with recurrence after adjusting for clinical risk factors, AF type, LA structure and function, and fibrosis (p 0.001). Furthermore, receiver-operating characteristics analysis showed SD-TPS improved prediction of recurrence better than clinical risk factors, LA structure and function, and fibrosis.Intra-atrial dyssynchrony during sinus rhythm is an independent predictor of recurrence after the first catheter ablation of paroxysmal or persistent AF. Assessment of intra-atrial dyssynchrony may improve ablation outcomes by refining patient selection.

Our world is faced with a global pandemic that threatens to overwhelm many national health care systems for a prolonged period. Consequently, the elective long-term cardiac implantable electronic device (CIED) management of millions of patients is potentially compromised, raising the likelihood of patients experiencing major adverse events owing to loss of CIED therapy. This review gives practical guidance to health care providers to help promptly recognize the requirement for expert consultation for urgent interrogation and/or surgery in CIED patients.

Abnormalities on cardiac magnetic resonance imaging (CMR) and positron emission tomography (PET) predict ventricular arrhythmias (VA) in patients with cardiac sarcoidosis (CS). Little is known whether concurrent abnormalities on CMR and PET increases the risk of developing VA. Our aim was to compare the additive utility of CMR and PET in predicting VA in patients with CS. We included all patients treated at our institution from 2000 to 2018 who (1) had probable or definite CS and (2) had undergone both CMR and PET. The primary endpoint was VA at follow up, which was defined as sustained ventricular tachycardia, sudden cardiac death, or any appropriate device tachytherapy. Fifty patients were included, 88% of whom had a left ventricular ejection fraction >35%. During a mean follow-up 4.1 years, 7/50 (14%) patients had VA. The negative predictive value of LGE for VA was 100% and the negative predictive value of FDG for VA was 79%. Among groups, VA occurred in 4/21 (19%) subjects in the LGE+/FDG+ group, 3/14 (21%) in the LGE+/FDG- group, and 0/15 (0%) in the FDG+/LGE- group. There were no LGE-/FDG- patients. In conclusion, CMR may be the preferred initial clinical risk stratification tool in patients with CS. FDG uptake without LGE on initial imaging may not add additional prognostic information regarding VA risk.

Background: Characterizing myocardial conduction velocity (CV) in patients with ischemic cardiomyopathy (ICM) and ventricular tachycardia (VT) is important for understanding the patient-specific proarrhythmic substrate of VTs and therapeutic planning. The objective of this study is to accurately assess the relation between CV and myocardial fibrosis density on late gadolinium–enhanced cardiac magnetic resonance imaging (LGE-CMR) in patients with ICM. Methods: We enrolled 6 patients with ICM undergoing VT ablation and 5 with structurally normal left ventricles (controls) undergoing premature ventricular contraction or VT ablation. All patients underwent LGE-CMR and electroanatomic mapping (EAM) in sinus rhythm (2960 electroanatomic mapping points analyzed). We estimated CV from electroanatomic mapping local activation time using the triangulation method that provides an accurate estimate of CV as it accounts for the direction of wavefront propagation. We evaluated the association between LGE-CMR intensity and CV with multilevel linear mixed models. Results: Median CV in patients with ICM and controls was 0.41 m/s and 0.65 m/s, respectively. In patients with ICM, CV in areas with no visible fibrosis was 0.81 m/s (95% CI, 0.59–1.12 m/s). For each 25% increase in normalized LGE intensity, CV decreased by 1.34-fold (95% CI, 1.25–1.43). Dense scar areas have, on average, 1.97- to 2.66-fold slower CV compared with areas without dense scar. Ablation lesions that terminated VTs were localized in areas of slow conduction on CV maps. Conclusions: CV is inversely associated with LGE-CMR fibrosis density in patients with ICM. Noninvasive derivation of CV maps from LGE-CMR is feasible. Integration of noninvasive CV maps with electroanatomic mapping during substrate mapping has the potential to improve procedural planning and outcomes. Visual Overview: A visual overview is available for this article.

Although atrial fibrillation (AF) is strongly associated with stroke, previous studies have shown suboptimal use of anticoagulation (AC). In particular, there is a lack of data on the long-term use of AC after AF catheter ablation. We followed up patients 1 to 5 years out from catheter ablation at the Johns Hopkins Hospital (JHH) to assess their long-term use of AC. We sent a survey to patients from the JHH AF database who underwent an AF catheter ablation between 01/01/2014 and 03/31/2018. Patients were asked whether they were still on AC, if they thought the ablation was successful in controlling AF symptoms and whether they had follow-up rhythm monitoring. Replies were compared with risk scores and demographic data from the electronic medical record. We sent the survey to 628 patients in the database meeting our inclusion criteria, and we received 289 responses. The average age of patients was 67 ± 10 with a median CHA2DS2-VASc of 2 and a median follow-up of 3.6 years. Overall, 81.6% of patients with a CHA2DS2-VASc >2 reported taking AC. Use of AC was positively correlated with a higher CHA2DS2-VASc score (p = 0.012) and older age (p = 0.028), but negatively correlated with a successful ablation (p = 0.040). The most common reason (50.0%) for not being on AC was that doctors were recommending stopping it after a successful ablation. In general, higher risk patients (older, higher CHA2DS2-VASC score) were more likely to remain on AC. However, patients who self-reported a successful ablation were less likely to remain on AC. There may be many patients who can tolerate AC, but are recommended to stop due to a successful ablation. It is still debated how successful AF ablation affects stroke risk. In conclusion, there is considerable variation in the long-term management of AC after an ablation, but for the present, it seems prudent to continue AC based on stroke risk scores until more definite data are available.

Objectives The aim of the current investigation is to examine whether use of high-frequency jet ventilation (HFJV) during pulmonary vein isolation (PVI) performed with force-sensing catheters is associated with improved outcomes. Background Catheter ablation is well established as therapy for symptomatic atrial fibrillation (AF). Reconnection following PVI is commonly observed during repeat ablation procedures. Technologies that may optimize catheter stability and lesion delivery include both force-sensing ablation catheters and HFJV. Methods Patients undergoing PVI at Johns Hopkins Hospital were prospectively enrolled in a registry. The study compared procedural characteristics, adverse event rates, and 1-year procedural outcomes in patients undergoing PVI supported either by standard ventilation or HFJV. Patient and procedural aspects were otherwise constant. Results Eighty-four HFJV patients and 84 matched control patients with 1-year outcome data were identified. Atrial arrhythmia recurrence occurred in 26 of 84 HFJV patients (31%) and 42 of 84 control patients (50%; p = 0.019). In patients with paroxysmal AF, arrhythmia recurrence in HFJV and control patients was 27.3% and 47.3%, respectively (p = 0.045). In patients with persistent AF, arrhythmia recurrence rates were not significantly different (37.9% in HFJV patients, 55.2% in control patients; p = 0.184). On multivariate analysis, HFJV was independently associated with improved freedom from arrhythmia recurrence. Vasopressor use during HFJV cases was significantly higher than during standard ventilation (79.7% vs. 22.4%; p = 0.001). Indices of catheter stability and contact force adequacy were significantly higher in the HFJV patients than in control patients. Complication rates in the 2 groups were similarly low. Conclusions Use of HFJV in patients undergoing PVI with radiofrequency force-sensing catheters is associated with improved outcomes, without appreciable increase in adverse procedural events.

BACKGROUND Pacemaker patients experience battery depletion that activates pacemaker's alert for replacement notification. Automatic reprogramming at replacement notification can result in loss of rate response and atrioventricular (AV) synchrony. OBJECTIVE To determine if relevant symptoms or clinical events may be associated with automatic reprogramming at replacement notification. METHODS Electronic medical record review was undertaken for 298 patients referred for pacemaker generator replacement. Primary endpoints were symptoms or clinical events during replacement notification period. RESULTS Following elimination of duplicate pacemaker replacements (n = 12), "near-replacement notification" or "recalled" (n = 15) and pacemakers at "end of life" (n = 5), 266 subjects were included. Three distinct reprogramming cohorts were identified; those with no change (control) in pacing mode (n = 46), those with loss of rate response (n = 154), and those with loss of AV synchrony ± rate response (n = 66). In total, 83 subjects (31.2%) had symptoms with significant differences seen between groups (control = 4.3%, loss of rate response = 26.0%, loss of AV synchrony ± rate response = 62.1%, P

Aims Historically, cardiac resynchronization therapy (CRT) response in non-left bundle branch block (non-LBBB) patients has been suboptimal in comparison with that observed in left bundle branch block patients. The electrical activation pattern of the left ventricle (LV) is different between these two QRS morphologies. Small non-randomized studies have suggested that targeting the LV wall with greatest electrical delay may be superior to conventional anatomical pacing from the lateral wall in non-LBBB patients. This article outlines the design and rationale of a prospective, randomized, pilot study, which assesses the effect of a non-traditional LV lead implant strategy on the clinical composite score after 12 months of follow-up in a non-LBBB patient population. Methods All patients will receive an Abbott quadripolar CRT-D system (Quartet 1458Q LV lead with Unify Quadra™, Quadra Assura™ CRT-D or any market-approved CRT-D device with quadripolar pacing capabilities). Patients will be randomized in a 2:1 ratio between a QLV-based implant strategy vs. standard of care. Up to 250 patients will be enrolled in the study. Conclusions If the primary endpoint is achieved, this study will provide important information about reducing the non-responder rate in non-LBBB patients and provide further evidence for the QLV-based implant strategy.

Background Patients go without pacemaker, defibrillator, and cardiac resynchronization therapies (devices) each year due to the prohibitive costs of devices. Objective We sought to examine data available from studies regarding contemporary risks of reused devices in comparison with new devices. Methods We searched online indexing sites to identify recent studies. Peer-reviewed manuscripts reporting infection, malfunction, premature battery depletion, and device-related death with reused devices were included. The primary study outcome was the composite risk of infection, malfunction, premature battery depletion, and death. Secondary outcomes were the individual risks. Results Nine observational studies (published 2009-2017) were identified totaling 2,302 devices (2,017 pacemakers, 285 defibrillators). Five controlled trials were included in meta-analysis (2,114 devices; 1,258 new vs 856 reused). All device reuse protocols employed interrogation to confirm longevity and functionality, disinfectant therapy, and, usually, additional biocidal agents, packaging, and ethylene oxide gas sterilization. Demographic characteristics, indications for pacing, and median follow-up were similar. There were no device-related deaths reported and no statistically significant difference in risk between new versus reused devices for the primary outcome (2.23% vs 3.86% respectively, P = 0.807, odds ratio = 0.76). There were no significant differences seen in the secondary outcomes for the individual risks of infection, malfunction, and premature battery depletion. Conclusions Device reuse utilizing modern protocols did not significantly increase risk of infection, malfunction, premature battery depletion, or device-related death in observational studies. These data provide rationale for proceeding with a prospective multicenter noninferiority randomized control trial.

Objectives This study examined the trend in growth of catheter ablation for ventricular tachycardia (VT) performed in the United States with analysis of rates and predictors of major adverse events. Background Sustained VT is a significant cause of sudden death, heart failure (HF), and recurrent shocks in implantable cardioverter-defibrillator (ICD) recipients. Catheter ablation for VT reduces arrhythmia recurrence. Limited data are available regarding the use, safety, and long-term outcomes after VT ablation. Methods Using the U.S. Medicare database linked to the Social Security Death Index, we examined the annual use of VT ablation in 21,073 patients over 12 years, with 30-day risk of mortality, nonfatal major adverse events (MAEs), 1-year risk of mortality, re-hospitalization, repeat ablation, and factors associated with adverse outcomes. Results Among 21,073 patients (age 70 ± 9 years; 77% men; 90% white), there were 1,581 (7.5%) non-fatal MAEs within 30 days. There were 963 (4.6%) vascular complications, 485 (2.3%) pericardial complications, and 201 (1%) strokes and/or transient ischemic attacks. Mechanical circulatory support use was infrequent (2.3%). The 30-day and 1-year mortality rates were 4.2% and 15.0%, respectively. The 1-year incidence of repeat ablation was 10.2 per 100 person-years and re-hospitalization for HF or VT was 15.4 per 100 person-years and 18 per 100 person-years, respectively. Patients with an ICD had increased 30-day (4.9% vs. 0.86%) and 1-year mortality (17.5% vs. 2.54% [22.9 per 100 person-years vs. 3.1 per 100 person-years]; hazard ratio [HR]: 2.93; 95% confidence interval [CI]: 2.21 to 3.88). Rates of hospitalization for HF (18 per 100 person-years vs. 1.8 per 100 person-years; HR: 4.00; 95% CI: 2.78 to 5.78) or VT recurrence (22.7 per 100 person-years vs. 2.1 per 100 person-years; HR: 5.70; 95% CI: 4.09 to 7.96) were also higher at 1 year. Between 2000 and 2012, annual VT ablation volumes increased >4-fold. Conclusions Catheter ablation for VT is frequently performed. Short-term MAEs and 1-year mortality is significant and is highest in patients with an ICD. These findings may provide greater insight of outcomes in an unselected real-world population undergoing VT ablation.

The P-wave terminal force in lead V1 (PTFV1) on the 12-lead electrocardiogram (ECG) quantifies left atrial (LA) structural and electrophysiologic abnormalities. We aimed to evaluate the association between PTFV1 and cerebrovascular accident (CVA) as well as LA structure and function in patients with atrial fibrillation (AF). We conducted a cross-sectional study of 229 patients with AF (60 ± 10years, 72% men) with (n = 21) and without (n = 208) a history of CVA, who underwent preablation ECG and cardiac magnetic resonance in sinus rhythm. PTFV1 was defined as the duration (in milliseconds) of the downward deflection of the P wave in lead V1 multiplied by the absolute value of its amplitude (in microvolts) on ECG. PTFV1 is associated with LA minimum volume (Vmin) and left ventricular ejection fraction but not associated with the extent of LA fibrosis quantified by cardiac magnetic resonance late gadolinium enhancement. In addition, PTFV1 is associated with CVA independent of the CHA2DS2-VASc score and LA Vmin (odds ratio 1.23; 95% confidence interval 1.08 to 1.40; p = 0.002). Furthermore, PTFV1 has an incremental value over the CHA2DS2-VASc score as a marker of CVA (p

AIMS Prior studies identified a relationship between epicardial bipolar and endocardial unipolar voltage. Whether the relationship is valid with smaller multielectrode mapping catheters has not been reported. We explored the association of right ventricular (RV) endocardial unipolar voltage mapping with epicardial bipolar voltage mapping using a multielectrode mapping catheter. METHODS Electrograms from patients who underwent multielectrode endocardial and epicardial RV electroanatomical mapping during ablation procedures were analyzed. Each endocardial mapping point was matched to the corresponding nearest epicardial point. The correlation between unipolar endocardial voltage and epicardial bipolar voltage was determined. The optimal unipolar threshold to detect epicardial low voltage (

Objectives The aim of this study was to examine atrial fibrillation (AF) substrate using different modalities (point-by-point [PBP], fast anatomic mapping [FAM], and late gadolinium enhancement [LGE] magnetic resonance imaging [MRI] mapping) in patients presenting for AF ablation. Background Bipolar voltage mapping, as part of AF ablation, is traditionally performed in a PBP approach using single-tip ablation catheters. Alternative techniques for fibrosis delineation include FAM with multi-electrode circular catheters and LGE MRI. The correlation between PBP, FAM, and LGE-MRI fibrosis assessment is unknown. Methods LGE MRI was performed pre-ablation in 26 patients (73% men, mean age 63 ± 8 years). Local image intensity ratio (IIR) was used to normalize myocardial intensities. PBP and FAM voltage maps were acquired, in sinus rhythm, prior to ablation and coregistered with LGE MRI. Results The mean bipolar voltage for all 19,087 FAM voltage points was 0.88 ± 1.27 mV, and the average IIR was 1.08 ± 0.18. In an adjusted mixed-effects model, each unit increase in local IIR was associated with a 57% decrease in bipolar voltage (p 0.74 corresponded to a bipolar voltage Conclusions LGE-MRI, FAM, and PBP mapping showed good correlation in delineating electroanatomic AF substrate. Each approach has fundamental technical characteristics, the awareness of which allows proper assessment of atrial fibrosis.

Atrial fibrillation (AF) is a commonly sustained atrial arrhythmia with associated morbidity and mortality. AF is associated with increased risk of thromboembolism and stroke, requiring use of anticoagulation. Anticoagulation decreases the risk of stroke but is associated with a higher risk of bleeding, necessitating discontinuation in some patients. The left atrial appendage is the likely source of thrombus in the majority of patients with AF. This has led to the development of left atrial appendage occlusion as a means to reduce stroke risk in patients who have a contraindication to long‐term anticoagulation. Multiple implantable devices have surfaced in the last few years, with some promising prospects. The main purpose of this review is to highlight the indications and use of these devices for left atrial appendage occlusion.

All contemporary pacemakers undergo automatic reprogramming upon reaching elective replacement indication due to battery depletion. The majority of such reprogramming will result in changes to both pacing mode and pacing rate. The exact software reprogramming varies considerably among pacemaker manufacturers and may even vary among models of the same manufacturer. Accordingly, it is essential for healthcare providers managing pacemaker patients to have a detailed understanding of the automatic reprogramming seen at elective replacement indication as well as their potential physiological and clinical consequences.

The implantable cardioverter-defibrillator (ICD) has become a routine part of medical care to prevent sudden cardiac death from ventricular arrhythmias (VAs). The initial creation and design of this life-saving device was primarily due to the work of Dr. Michel Mirowski and others. Since first implantation in humans nearly 40 years ago, numerous studies have shown the efficacy of ICDs in decreasing mortality in populations that have sustained or are at risk for developing a life-threatening VA. There has been a tremendous evolution in the size, function, and mechanisms by which ICDs treat VAs in the past decades. Continued research and development, will allow for further refinement of this life-saving technology.

BACKGROUND Pacemaker battery depletion triggers alert for replacement notification and results in automatic reprogramming, which has been shown to be associated with relevant cardiorespiratory symptoms and adverse clinical events. OBJECTIVE Determine if electrocardiogram (ECG) pacing features may be predictive of pacemaker battery depletion and clinical risk. METHODS This is an ECG substudy of a cohort analysis of 298 subjects referred for pacemaker generator replacement from 2006 to 2017. Electronic medical record review was performed; clinical, ECG, and pacemaker characteristics were abstracted. We applied two ECG prediction rules for pacemaker battery depletion that are relevant to all major pacemaker manufacturers except Boston Scientific and MicroPort: (1) atrial pacing not at a multiple of 10 and (2) nonsynchronous ventricular pacing not at a multiple of 10, to determine diagnostic sensitivity, specificity, and risk in applicable ECG subjects. RESULTS We excluded 32 subjects not at replacement notification or duplicate surgeries. Overall, 176 of 266 subjects (66.2%) demonstrated atrial pacing or nonsynchronous ventricular pacing on preoperative ECG. When utilizing both rules, 139 of 176 preoperative ECGs and 12 of 163 postoperative ECGs met criteria for battery depletion yielding reasonable sensitivity (79.0%), high specificity (92.6%), and a positive likelihood ratio of 11.6:1. These rules were associated with significant increase in cardiorespiratory symptoms (P

Background: Previous studies showed that the quantity of the left atrial (LA) periatrial fat tissue predicts recurrence after catheter ablation of atrial fibrillation (AF). We hypothesized that the quality of the LA periatrial fat tissue, measured by the mean computed tomography attenuation, predicts recurrence after AF ablation independent of the quantity of the LA periatrial fat tissue. Methods: We included 143 consecutive patients with drug-refractory AF referred for the first catheter ablation of AF (62.2±10 years, 40% nonparoxysmal AF). All participants had a preablation cardiac computed tomography. We measured the quantity of the LA periatrial fat tissue by the area (millimeter square) and the quality by the mean computed tomography attenuation (Hounsfield units) in a standard 4-chamber view. Results: Patients with AF recurrence after ablation (n=57) had a significantly larger fat area (167.6 [interquartile range, 124.1–255] versus 145.4 [95.6–229.3] mm 2 ; P =0.018) and a higher fat attenuation (−92.0±9.8 versus −96.5±9.4 Hounsfield units; P =0.006) than those without recurrence (controls). LA fat attenuation was correlated with LA fat volume and LA bipolar voltage by invasive mapping and was associated with AF recurrence after adjusting for clinical risk factors, including body mass index, AF type, LA dimension, and fat area (hazard ratio, 2.65; P =0.001). Conclusions: The quality of the LA periatrial fat tissue is an independent predictor of recurrence after the first AF ablation. Assessment of LA periatrial fat attenuation can improve AF ablation outcomes by refining patient selection.

BACKGROUND Patients with cardiac sarcoidosis (CS) may present with arrhythmic events (AE): atrioventricular block (AVB) and/ or ventricular arrhythmias (VA). We sought to: (a) use regional analysis of cardiac magnetic resonance imaging (CMR) to describe anatomic and functional phenotypes of patients with CS and AE; (b) Assess the association of regional CMR abnormalities with the combined endpoint of death, heart transplantation (HT) and AE; and (c) use machine learning (ML) to predict the combined endpoint based on CMR features. METHODS we included 76 patients with CS and CMR. We analyzed cine images to determine regional longitudinal (LS) and radial strain (RS); and late gadolinium enhancement imaging to determine regional scar burden (%scar). RESULTS Patients with AVB (n = 7), compared with those without, had higher %scar in the anterior (21.8 ± 27.4 vs 5.1 ± 8.9; P = 0.0005) and anteroseptal (19.3 ± 24.5 vs 3.5 ± 5.5; P

Background: Abnormalities on cardiac imaging (cardiac magnetic resonance imaging [CMR] or positron emission tomography [PET]), left ventricular ejection fraction (LVEF), and electrophysiology study (EPS) all predict ventricular arrhythmias (VA) in patients with cardiac sarcoidosis (CS). We sought to assess the utility of EPS in patients with CS and abnormal cardiac imaging, focusing on those with LVEF >35%. Methods: We identified all patients treated at our institution from 2000 to 2017 who: 1.) had probable or definite CS; 2.) had either late gadolinium enhancement (LGE) on CMR or abnormal 18-flourodeoxyglucose (FDG) uptake on PET, and 3.) had undergone EPS. The primary endpoint was VA during follow up. Results: Twenty five patients were included, of whom 10 (40%) had positive EPS. During a mean follow-up of 4.8 +/− 3.4 years, 11 (44%) patients had VA. The positive predictive value (PPV) of EPS for VA was 100% and the negative predictive value (NPV) of EPS for VA was 93%. Among 12 patients with LVEF >35% and no prior VA, the PPV of EPS for VA was 100% and the NPV of EPS for VA was 90%. Conclusion: EPS may help with risk stratification in patients with CS and abnormal imaging, especially those without conventional indications for ICD placement. Among patients with LVEF >35% and no history of prior VA, a negative EPS has good positive and negative predictive value for future VA events. Keywords: Cardiac sarcoidosis, Ventricular arrhythmia, Sudden cardiac death, Electrophysiology study, Implantable cardioverter defibrillator

Introduction The interplay between electrical activation and mechanical contraction patterns is hypothesized to be central to reduced effectiveness of cardiac resynchronization therapy (CRT). Furthermore, complex scar substrates render CRT less effective. We used novel cardiac computed tomography (CT) and non-invasive electrocardiographic imaging (ECGI) techniques in an ischemic dyssynchronous heart failure (DHF) animal model to evaluate electrical and mechanical coupling of cardiac function, tissue viability and venous accessibility of target pacing regions. Methods and Results Ischemic DHF was induced in 6 dogs using coronary occlusion, left bundle ablation and tachy RV pacing. Full body ECG was recorded during native rhythm followed by volumetric first-pass and delayed enhancement CT. Regional electrical activation were computed and overlaid with segmented venous anatomy and scar regions. Reconstructed electrical activation maps show consistency with LBBB starting on the RV and spreading in a “U-shaped” pattern to the LV. Previously reported lines of slow conduction are seen parallel to anterior or inferior inter-ventricular grooves. Mechanical contraction showed large septal to lateral wall delay (80±38 vs 123 ± 31 ms, p = 0.0001). All animals showed electromechanical correlation except dog 5 with largest scar burden. Electromechanical decoupling was largest in basal lateral LV segments. Conclusion We demonstrated a promising application of CT in combination with ECGI to gain insight into electromechanical function in ischemic dyssynchronous heart failure that can provide useful information to study regional substrate of CRT candidates. This article is protected by copyright. All rights reserved

The feasibility and safety of postmortem cardiovascular implantable electronic device (CIED; pacemaker or defibrillator) retrieval for reuse has been shown. To date, studies indicate a low yield of reusable postmortem CIEDs (17%-30%).The purpose of this study was to test the hypothesis that a higher rate of reusable CIEDs would be identified upon postmortem retrieval when an institutional protocol for systematic and routine acquisition, interrogation, reprogramming, and manufacturer analysis was used.Over a 6-year period, all subjects referred for autopsy underwent concomitant CIED pulse generator retrieval and enrollment in the Johns Hopkins Post-Mortem CIED Registry. CIEDs were interrogated, reprogrammed, and submitted for manufacturer analysis.In total, 84 autopsies had CIEDs (37 pacemakers, 47 implantable cardioverter-defibrillators). CIEDs were implanted 2.84 ± 2.32 years before death, with 30% implanted1 year before death. Overall, CIED postmortem longevity was 4.79 ± 3.41 years, with 56% demonstrating longevity ≥4 years (this group had an estimated mean longevity of 7.37 ± 2.44 years). Manufacturer analyses uncovered 2 falsely triggered elective replacement indication alerts, confirmed 5 correctly triggered elective replacement indication alerts, identified a recalled pacemaker, and verified that a defibrillator had undergone nonprogrammable hard reset.When a protocol for systematic and routine postmortem CIED retrieval, interrogation, reprogramming, and analysis was used, we noted that60% of pacemakers and50% of defibrillators demonstrated normal functional status with projected longevities7 years on average. Formation of a national hospital-based "CIED donor network" would facilitate larger scale charitable efforts in underserved countries.

Background Skeletal muscle activation has been implicated as the source of pain associated with implantable cardioverter-defibrillator shocks. We hypothesized that the skeletal muscle response to defibrillatory shocks could be attenuated with a tetanizing prepulse immediately before biphasic shock delivery. Objective The purpose of this study was to test the ability of tetanizing prepulses to reduce the skeletal muscle activation associated with defibrillation. Methods Seven adult pigs were studied. A left ventricular coil and subcutaneous dummy can in the right thorax were used to deliver either pure biphasic waveforms or test waveforms consisting of a tetanizing pulse of high-frequency alternating current (HFAC) ramped to an amplitude of 5–100 V over 0.25–1 second, immediately followed by a biphasic shock of approximately 9 J (ramped HFAC and biphasic [rHFAC+B]). We used limb acceleration and rate of force development as surrogate measures of pain. Test and control waveforms were delivered in sinus rhythm and induced ventricular fibrillation to test defibrillation efficacy. Results Defibrillation threshold energy was indistinguishable between rHFAC+B and pure biphasic shocks. Peak acceleration and rate of force development were reduced by 72% ± 7% and 71% ± 22%, respectively, with a 25-V, 1-second rHFAC+B waveform compared with pure biphasic shocks. Notably, rHFAC+B with a 9-J biphasic shock produced significantly less skeletal muscle activation than a 0.1-J pure biphasic shock. Conclusion A putative source of implantable cardioverter-defibrillator shock-related pain can be mitigated using a tetanizing prepulse followed by biphasic shock. Human studies will be required to assess true pain reduction with this approach.