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Post-myocardial infarction ventricular tachycardia (VT) is due to re-entry through surviving conductive myocardial corridors across infarcted tissue. However, not all conductive corridors participate in re-entry.This study sought to test the hypothesis that critical VT corridors are more likely to traverse near lipomatous metaplasia (LM) and that current loss is reduced during impulse propagation through such corridors.Among 30 patients in the Prospective 2-center INFINITY (Intra-Myocardial Fat Deposition and Ventricular Tachycardia in Cardiomyopathy) study, potential VT-viable corridors within myocardial scar or LM were computed from late gadolinium enhancement cardiac magnetic resonance images. Because late gadolinium enhancement highlights both scar and LM, LM was distinguished from scar by using computed tomography. The SD of the current along each corridor was measured.Scar exhibited lower impedance than LM (median Z-score -0.22 [IQR: -0.84 to 0.35] vs -0.07 [IQR: -0.67 to 0.54]; P lt; 0.001). Among all 381 corridors, 84 were proven to participate in VT re-entry circuits, 83 (99%) of which traversed or were adjacent to LM. In comparison, only 13 (4%) non-VT corridors were adjacent to LM. Critical corridors adjacent to LM displayed lower SD of current compared with noncritical corridors through scar but distant from LM (2.0 [IQR: 1.0 to 3.4] μA vs 8.4 [IQR: 5.5 to 12.8] μA; P lt; 0.001).Corridors critical to VT circuitry traverse infarcted tissue through or near LM. This association is likely mediated by increased regional resistance and reduced current loss as impulses traverse corridors adjacent to LM.

Indoor air pollution represents a modifiable risk factor for respiratory morbidity in COPD. The effects of indoor air pollution, as well as the impact of interventions to improve indoor air quality, on cardiovascular morbidity in COPD remain unknown.To determine the association between indoor particulate matter(PM) and heart rate variability(HRV), a measure of cardiac autonomic function tied to cardiovascular morbidity and mortality, as well as the impact of household air purifiers on HRV.Former smokers with moderate-severe COPD were recruited from a six-month randomized controlled trial of a portable air cleaner intervention, to undergo paired assessment of both in-home PM and HRV, using 24-hour Holter monitoring, at up to 5 time points. Primary outcomes were HRV measures tied to cardiovascular morbidity (SDNN and RMSSD).85 participants contributed 317 HRV measurements. A two-fold increase in household PM2.5 was associated with decreases in SDNN (ß -2.98% [95% CI, -5.12 to -0.78]) and RMSSD (ß -4.57% [95% CI, -10.1 to -1.60]). The greatest effects were observed with ultrafine particles(100 nm) (RMSSD; ß -16.4% [95% CI, -22.3 to -10.1]) and among obese participants. Participants randomized to the active air cleaner saw improvements in RMSSD (ß 25.2% [95% CI, 2.99 to 52.1]), but not SDNN (ß 2.65% [95% CI, -10.8 to 18.1]), compared to the placebo group.This is the first US study to describe the association between household PM and cardiac autonomic function among individuals with COPD, and the potential cardiovascular health benefits of household air cleaners.

AimsPost-infarct myocardium contains viable corridors traversing scar or lipomatous metaplasia (LM). Ventricular tachycardia (VT) circuitry has been separately reported to associate with corridors that traverse LM and with repolarization heterogeneity. We examined the association of corridor activation recovery interval (ARI) and ARI dispersion with surrounding tissue type.Methods and resultsThe cohort included 33 post-infarct patients from the prospective Intra-Myocardial Fat Deposition and Ventricular Tachycardia in Cardiomyopathy (INFINITY) study. We co-registered scar and corridors from late gadolinium enhanced magnetic resonance, and LM from computed tomography with intracardiac electrogram locations. Activation recovery interval was calculated during sinus or ventricular pacing, as the time interval from the minimum derivative within the QRS to the maximum derivative within the T-wave on unipolar electrograms. Regional ARI dispersion was defined as the standard deviation (SD) of ARI per AHA segment (ARISD). Lipomatous metaplasia exhibited higher ARI than scar [325 (interquartile range 270–392) vs. 313 (255–374), P < 0.001]. Corridors critical to VT re-entry were more likely to traverse through or near LM and displayed prolonged ARI compared with non-critical corridors [355 (319–397) vs. 302 (279–333) ms, P < 0.001]. ARISD was more closely associated with LM than with scar (likelihood ratio χ2 50 vs. 12, and 4.2-unit vs. 0.9-unit increase in 0.01*Log(ARISD) per 1 cm2 increase per AHA segment). Additionally, LM and scar exhibited interaction (P < 0.001) in their association with ARISD.ConclusionLipomatous metaplasia is closely associated with prolonged local action potential duration of corridors and ARI dispersion, which may facilitate the propensity of VT circuit re-entry.

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.

Gray zone, a measure of tissue heterogeneity on late gadolinium enhanced-cardiac magnetic resonance (LGE-CMR) imaging, has been shown to predict ventricular arrhythmias (VAs) in ischemic cardiomyopathy (ICM) patients. However, no studies have described whether left ventricular (LV) tissue heterogeneity and intramyocardial fat mass on contrast-enhanced computed tomography (CE-CT), which provides greater spatial resolution, is useful for assessing the risk of VAs in ICM patients with LV systolic dysfunction and no previous VAs.The purpose of this proof-of-concept study was to determine the feasibility of measuring global LV tissue heterogeneity and intramyocardial fat mass by CE-CT for predicting the risk of VAs in ICM patients with LV systolic dysfunction and no previous history of VAs.Patients with left ventricular ejection fraction ≤35% and no previous VAs were enrolled in a prospective, observational registry and underwent LGE-CMR. From this cohort, patients with ICM who additionally received CE-CT were included in the present analysis. Gray zone on LGE-CMR was defined as myocardium with signal intensity (SI)peak SI of healthy myocardium but50% maximal SI. Tissue heterogeneity on CE-CT was defined as the standard deviation of the Hounsfield unit image gradients (HU/mm) within the myocardium. Intramyocardial fat on CE-CT was identified as regions of image pixels between -180 and -5 HU. The primary outcome was VAs, defined as appropriate implantable cardioverter-defibrillator shock or sudden arrhythmic death.The study consisted of 47 ICM patients, 13 (27.7%) of whom experienced VA events during mean follow-up of 5.6 ± 3.4 years. Increasing tissue heterogeneity (per HU/mm) was significantly associated with VAs after multivariable adjustment, including for gray zone (odds ratio [OR] 1.22;In ICM patients, CE-CT-derived LV tissue heterogeneity was independently associated with VAs and may represent a novel marker useful for risk stratification.

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.

Aims Multiple wavefront pacing (MWP) and decremental pacing (DP) are two electroanatomic mapping (EAM) strategies that have emerged to better characterize the ventricular tachycardia (VT) substrate. The aim of this study was to assess how well MWP, DP, and their combination improve identification of electrophysiological abnormalities on EAM that reflect infarct remodelling and critical VT sites. Methods and results Forty-eight personalized computational heart models were reconstructed using images from post-infarct patients undergoing VT ablation. Paced rhythms were simulated by delivering an initial (S1) and an extra-stimulus (S2) from one of 100 locations throughout each heart model. For each pacing, unipolar signals were computed along the myocardial surface to simulate substrate EAM. Six EAM features were extracted and compared with the infarct remodelling and critical VT sites. Concordance of S1 EAM features between different maps was lower in hearts with smaller amounts of remodelling. Incorporating S1 EAM features from multiple maps greatly improved the detection of remodelling, especially in hearts with less remodelling. Adding S2 EAM features from multiple maps decreased the number of maps required to achieve the same detection accuracy. S1 EAM features from multiple maps poorly identified critical VT sites. However, combining S1 and S2 EAM features from multiple maps paced near VT circuits greatly improved identification of critical VT sites. Conclusion Electroanatomic mapping with MWP is more advantageous for characterization of substrate in hearts with less remodelling. During substrate EAM, MWP and DP should be combined and delivered from locations proximal to a suspected VT circuit to optimize identification of the critical VT site.

BACKGROUND: External defibrillators are used for arrhythmia cardioversion and for defibrillating during cardiac arrest. During defibrillation, short-duration Biphasic pulses cause intense motion due to rapid chest-wall muscle contraction. A reduced-motion external defibrillator (RMD) was constructed by integrating a commercial defibrillator with a Tetanizing-waveform generator. A long-duration low-amplitude Tetanizing-waveform slowly stimulated the chest musculature prior to the Biphasic pulse, reducing muscle contraction during the shock. OBJECTIVE: Evaluate RMD defibrillation in swine for subject-motion during defibrillation pulses and for defibrillation effectiveness. RMD defibrillation can reduce the duration of arrhythmia ablation-therapy or simplify cardioversion procedures. METHODS: The Tetanizing unit delivered a triangular 1-kHz pulse of 0.25–2.0sec duration and 10–100Volt peak amplitude, subsequently triggering the conventional defibrillator to output standard 1–200J energy Biphasic pulses at the next R-wave. Forward-limb motion was evaluated by measuring Peak Acceleration and Limb Work during RMD (Tetanizing+Biphasic) or Biphasic-pulse-only waveforms at 10(−3)sec sampling-rate. Seven swine were arrested electrically and subsequently defibrillated. Biphasic-pulse-only and RMD defibrillations were repeated 25–35 times/swine, varying Tetanizing parameters and the Biphasic-pulse energy. Defibrillation thresholds (DFTs) were established by measuring the minimum energy required to restore sinus-rhythm with Biphasic-pulse-only or RMD defibrillations. RESULTS: Two forward-limb acceleration-peaks occurred during both the Tetanizing-waveform and Biphasic-pulse, indicating rapid and slower nociceptic (pain-sensation) nerve-fiber activation. Optimal RMD Tetanizing-parameters (25–35V, 0.25–0.75sec duration), relative to Biphasic-pulse-only defibrillations, resulted in 74±10% smaller Peak Accelerations and 85±10% reduced Limb Work. DFT energies were identical, comparing RMD to Biphasic-pulse-only defibrillations. CONCLUSION: Relative to conventional defibrillations, RMD defibrillations maintain rhythm-restoration efficiency with drastically reduced subject-motion.

Introduction: Increasing numbers of elderly patients are undergoing catheter ablation (CA) of atrial fibrillation (AF). However, data regarding the experience with this procedure in the octogenarians are limited. Objective: To describe safety and efficacy of index CA of AF and predictors of arrhythmia recurrence in octogenarians. Methods: We conducted a retrospective analysis of patients > 80 years old undergoing index AF ablation between 2012 and 2020 at a large academic medical center. Procedural complications and efficacy, defined as freedom from any atrial tachyarrhythmia (ATA) lasting ≥30 seconds, were assessed. All patients were followed for at least 1 year. Predictors of ATA recurrence were also evaluated. Results: A total of 69 patients were included in our analysis. The median age was 82 (81-85) years, 53.6% were men, and 36.2% had persistent AF (PsAF). The mean left atrial (LA) diameter was 4.3 + 0.8 cm, while the median CHA 2 DS 2 -VASc score was 4 (3-4.5). The majority (n=48, 69.6%) underwent radiofrequency ablation, and the remaining (n=21, 30.4%) patients underwent cryoballoon ablation. Pulmonary vein (PV) isolation was performed in all patients, and 31 (44.9%) patients underwent additional non-PV ablation. None of the patients developed any procedural complications. Acute procedural success with PV isolation was achieved in all the patients, and a total of 44 (63.8%) patients remained free of ATA at 1-year of follow-up. Among the patients with ATA recurrence, 24 (34.8%) were on antiarrhythmic drugs, and 12 (17.4%) patients underwent repeat ablation. Anticoagulation was continued in all the patients. In a multivariable model, only AF type (PsAF) was associated with ATA recurrence at 1-year follow-up (HR=3.42, CI: 1.17-9.94, p=0.02). Conclusion: CA of AF appears to be a safe and effective procedure in octogenarians. AF type (PsAF) is an independent predictor of ATA recurrence at 1-year follow-up.

Introduction: Despite advances in atrial fibrillation (AF) management, patients with AF continue to experience poor quality of life and adverse outcomes. Engagement of patients, caregivers, and clinicians to identify challenges in AF management can inform strategies to improve quality of life and improve AF related outcomes. Methods: We conducted virtual Human Centered Design (HCD) sessions with a) patients with AF and their caregivers to understand challenges in living with AF, and b) clinicians caring for patients with AF to identify difficulties encountered in AF management. During HCD sessions, we engaged participants to answer open-ended questions. Transcripts of audio recorded sessions were coded and emerging themes were identified. Results: 8 patients (25% African American, 13% Asian), 3 caregivers, and 7 clinicians participated in HCD sessions. Median (interquartile range) patient age was 69 years (58 - 78). Major themes from the patient and caregiver perspective included inadequate education on AF, lack of guidance on AF risk factor modification, lack of support networks, and absence of systems to guide patients when experiencing recurrent AF episodes. Major themes from the clinician perspective were complementary to patient and caregiver input. Themes included inadequate patient education due to limited time clinicians can spend with patients, lack of AF risk factor modification programs, and lack of streamlined services to allow timely communication with patients without increasing the administrative burden for physicians (Figure 1). Conclusions: A diverse group of patients, their caregivers, and clinicians identified lack of adequate education, guidance on AF risk factor modification as well as poorly structured patient-clinician communication as major challenges in AF care. Our findings are informing development of mobile health application addressing identified challenges with a goal to improve quality of life and adverse AF outcomes.

Background: We developed a novel RIVAL system that consists of a CT-based computational simulation to identify VT circuits and an ECG-based automated approach to localize VT exit sites. Objective: Prospectively assess the ability of the RIVAL system to localize VT circuits and exits. Methods: Patients presenting for VT ablation were enrolled into the study. Pre-procedural cardiac CT was performed and used to conduct heart simulations for predicting VT circuits. The patient’s CT geometry with the predicted VT circuits was registered to the electroanatomic shell created during the procedure and imported into the RIVAL program. During the procedure, exit sites of induced VTs are localized in real-time using the 12-lead ECG onto the patient-specific CT surface. Predicted ablation regions obtained by combining RIVAL-predicted VT circuits with exit sites were analyzed offline to assess localization accuracy to the invasive VT ablation procedure. Results: Four patients with ischemic cardiomyopathy undergoing VT ablation had preprocedural cardiac CT. In P1, two VTs were induced during the procedure. The RIVAL predicted 2 VT circuits and achieved a mean localization error of 7.0mm for VT exit site prediction (Fig1). There was a spatial concordance between the predicted ablation areas and the clinical ablation regions. For P2, three VTs were induced during the VT ablation. A large area of scar was associated with 6 RIVAL-predicted VT circuits. The exit site localization accuracy could not be precisely quantitated because the VTs terminated with ablation at a mid-diastolic site. For P3, no VTs were inducible, however substrate modification (SM) was performed in the anterior-apical LV. The RIVAL predicted only one VT circuit located in the area where SM was performed. No VT was induced for P4 and the RIVAL did not predict any VT circuits. Conclusions: The RIVAL predicts the VT circuit and exit accurately, which may improve the precision of ablation therapies and procedure outcomes.

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.