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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.

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 implantation approach (control arm) in patients with non-left bundle branch block.Limited data exist on cardiac resynchronization therapy effectiveness in patients with non-left bundle branch block. Clinicians generally deliver cardiac resynchronization therapy through an anatomical implantation approach; however, targeting the QLV may serve as an individualized implantation strategy in non-left bundle branch block patients.The study enrolled 248 subjects at 29 U.S. centers. Subjects were randomized in a 2:1 ratio between a QLV-based implantation approach and anatomical implantation approach and were implanted with a St. Jude Medical quadripolar cardiac resynchronization therapy defibrillator system. The primary endpoint was the clinical composite score after 12 months of follow-up.The study analyzed 191 available subjects at 12 months of follow-up (128 QLV arm, 63 control arm). Of these, 39 subjects (26 in the QLV arm and 13 in the control arm) had heart failure events (8 cardiac deaths and 31 heart failure hospitalizations). Aside from New York Heart Association functional class, there were no other significant differences in baseline characteristics between the 2 arms. The responder rate at 12 months measured by the clinical composite score was 67.2% in the QLV arm and 73.0% in the control arm (p = 0.506).Although patient-tailored left ventricular lead placement guided by QLV is promising, we observed no difference in outcome between the QLV-based implantation approach and the conventional anatomical implantation approach.

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.

Electromechanical de-coupling is hypothesized to explain non-response of dyssynchrony patient to cardiac resynchronization therapy (CRT). In this pilot study, we investigated regional electromechanical uncoupling in 10 patients referred for CRT using two non-invasive electrical and mechanical imaging techniques (CMR tissue tracking and ECGI).Reconstructed regional electrical and mechanical activation captured delayed LBBB propagation direction from septal to anterior/inferior and finally to lateral walls as well as from LV apical to basal. All 5 responders demonstrated significantly delayed mechanical and electrical activation on the lateral LV wall at baseline compared to the non-responders (P.05). On follow-up ECGI, baseline electrical activation patterns were preserved in native rhythm and global LV activation time was reduced with biventricular pacing.The combination of novel imaging techniques of ECGI and CMR tissue tracking can be used to assess spatial concordance of LV electrical and mechanical activation to gain insight into electromechanical coupling.

Prognostic significance of left atrial (LA) function in patients with atrial fibrillation (AF) is poorly defined.To examine the association of LA function measured with cardiac magnetic resonance (CMR) feature-tracking and AF recurrence following catheter ablation.One hundred and twenty-one AF patients (72% paroxysmal, mean age 59 ± 10 years) were enrolled. Baseline LA function was measured by calculating passive, active, and total emptying fractions (LAEF) and analysis of global longitudinal strain and strain rates. Patients were followed up for recurrence of AF or atrial tachycardia (AT). Hazard ratios for recurrence were calculated using Cox proportional models adjusted for potential clinical confounders, type of AF, left ventricular ejection fraction, AF duration, LA volume, and late gadolinium enhancement (LGE).During a mean follow-up of 18 ± 9 months, 52 patients (43%) experienced recurrent AF/AT. Patients with recurrent AF/AT had higher baseline LA volume index and lower LA passive, and total LAEF (P.05 for all). The baseline peak LA strain and strain rates in all phases of LA function were lower in the AF/AT recurrence group (P.01 for all). In multivariable analysis total LAEF, peak LA strain, and systolic and late diastolic strain rates were associated with recurrence. Both peak LA strain and total LAEF improved prediction of recurrent AT/AF compared to the baseline clinical model, including LA LGE (C statistic 0.82 vs 0.77, P.05 for both total LAEF and peak LA strain).LA reservoir function was independently associated with recurrent AF/AT after PVI and can additionally improve risk stratification in patients undergoing PVI.

Background The extent of left atrial (LA) late gadolinium enhancement (LGE), as a surrogate for fibrosis, has been associated with atrial fibrillation (AF) recurrence after catheter ablation. Furthermore, there is ex vivo evidence that islands of fibrosis may anchor fibrillatory rotors. Objective The purpose of this study was to examine the anatomical association of AF rotors with LA and right atrial (RA) LGE on cardiac magnetic resonance. Methods The cohort included 9 patients with persistent AF (mean age 61.1 ± 9.7 years) who underwent LGE cardiac magnetic resonance before AF ablation using the focal impulse and rotor modulation system. The extent of LA and RA LGE was quantified globally and in each of the 7 sectors: LA posterior/inferior wall, anterior wall, roof, left and right pulmonary vein antra, and RA lateral and septal regions. The multivariable association of rotor incidence with global and per sector LGE extent was examined using multivariable Bernoulli logistic regression estimated by generalized estimating equations. Results The mean RA and LA volumes were 113.2 ± 37.31 and 143.03 ± 58.25 mL, respectively. The mean RA and LA LGE burden was 17.2% ± 11.0% and 17.4% ± 14.4%, respectively. A total of 18 LA rotors and 9 RA rotors were identified in all patients. No univariable or multivariable association was observed between global or per sector LGE extent and focal impulse and rotor modulation rotor incidence. Conclusion In this cohort of patients, there was no association between AF rotor incidence and the global or regional extent of RA and LA LGE.

We describe the novel use of bilateral cardiac sympathectomy in a woman with end-stage heart failure caused by ventricular tachycardia refractory to standard medical therapy who was under consideration for heart transplantation. Postoperatively, our patient has not experienced any symptoms of ventricular tachycardia, has returned to normal physical activity, and is no longer under consideration for transplantation as a result of the improvement in her cardiac function. Bilateral sympathectomy can be more effective than unilateral sympathectomy or percutaneous stellate ganglion blockade in patients with refractory ventricular tachycardia. Careful patient selection is necessary to identify patients who will benefit most from the procedure.

Background Ventricular arrhythmias (VAs) in cardiac sarcoidosis (CS) are frequently refractory to both antiarrhythmic drug (AAD) therapy and catheter ablation (CA). Cardiac sympathetic denervation (CSD) has been shown to reduce VA burden and implantable cardioverter-defibrillator (ICD) shocks in patients with nonischemic cardiomyopathy. Objective We aimed to report our center's preliminary experience with CSD in patients with known or presumed CS and refractory VAs. Methods Patients with CS and refractory VAs who underwent CSD at our institution were included. Patient characteristics, procedural outcomes, and number of arrhythmic events including ICD shocks pre- and post-CSD are reported. Results Five patients with CS (mean age 53 ± 11 years; 2 men [40%]; mean left ventricular ejection fraction 38% ± 11%) underwent CSD for VA refractory to AAD therapy and CA. Four of 5 patients underwent bilateral CSD; 1 patient underwent right-sided sympathectomy only because of poor intraoperative visualization on the left. Procedural complications included hemothorax in 1 patient and azygous vein injury in 1 patient. The median number of ICD shocks in the 6 months pre-CSD was 5. During a median follow-up of 26 months (range 5–29 months), the median number of ICD shocks post-CSD was 0; 1 patient had sustained VA that was below the threshold for device therapy, and 1 patient had symptomatic premature ventricular contractions; both underwent repeat CA. In addition, 1 patient required cardiac transplantation for progressive heart failure. Conclusion CSD may be a feasible therapeutic adjunct for patients with CS and VA refractory to AAD therapy and CA.

OBJECTIVES: We examined RFCA lesions within and around scar by cardiac magnetic resonance imaging (CMR) and histology. BACKGROUND: Substrate modification by radiofrequency catheter ablation (RFCA) is the cornerstone therapy for ventricular arrhythmias. RFCA in scarred myocardium, however, is not well understood. METHODS: We performed electroanatomical mapping and RFCA in the left-ventricles of 8 swine with myocardial infarction. Non-contrast-enhanced T1-weighted (T1w) and contrast-enhanced CMR after RFCA were compared to gross pathology and histology. RESULTS: Of 59 lesions, 17 were in normal myocardium (NL, voltage > 1.5mV), 21 in border zone (BZ, 0.5–1.5mV), and 21 in scar (< 0.5mV). All RFCA lesions were enhanced in T1w CMR, while scar was hypo-intense, allowing discrimination between normal myocardium, scar, and RFCA lesions. With contrast-enhancement, lesions and scar were similarly enhanced and not distinguishable. Lesion width and depth in T1w CMR correlated with necrosis in pathology (both; r(2)=0.94, p

The diagnosis of cardiac sarcoidosis (CS), especially in cases where there is limited or no extracardiac involvement, is challenging. Patients with CS are at increased risk of ventricular arrhythmias and sudden cardiac death. Several techniques for risk stratification for sudden cardiac death have been proposed in this population, including advanced cardiac imaging and electrophysiology study. Clinical ventricular arrhythmias in patients with CS may be treated with immunosuppressant therapy, antiarrhythmic drugs, catheter ablation, or implantable cardioverter-defibrillator placement. This article will provide an update on techniques for diagnosing CS, risk stratifying patients with CS for sudden cardiac death, and treating patients with CS with ventricular arrhythmias, focusing on evidence that has become available since publication of the 2014 Heart Rhythm Society Expert Consensus Statement on the Diagnosis and Management of Arrhythmias Associated With Cardiac Sarcoidosis.

Background: Recent studies suggest that left atrial (LA) late gadolinium enhancement (LGE) can quantify the underlying tissue remodeling that harbors atrial fibrillation (AF). However, quantification of LA-LGE requires labor-intensive magnetic resonance imaging acquisition and postprocessing at experienced centers. LA intra-atrial dyssynchrony assessment is an emerging imaging technique that predicts AF recurrence after catheter ablation. We hypothesized that 1) LA intra-atrial dyssynchrony is associated with LA-LGE in patients with AF and 2) LA intra-atrial dyssynchrony is greater in patients with persistent AF than in those with paroxysmal AF. Method: We conducted a cross-sectional study comparing LA intra-atrial dyssynchrony and LA-LGE in 146 patients with a history of AF (60.0 ± 10.0 years, 30.1% nonparoxysmal AF) who underwent pre-AF ablation cardiac magnetic resonance (CMR) in sinus rhythm. Using tissue-tracking CMR, we measured the LA longitudinal strain in two- and four-chamber views. We defined intra-atrial dyssynchrony as the standard deviation (SD) of the time to peak longitudinal strain (SD-TPS, in %) and the SD of the time to the peak pre-atrial contraction strain corrected by the cycle length (SD-TPSpreA, in %). We used the image intensity ratio (IIR) to quantify LA-LGE. Results: Intra-atrial dyssynchrony analysis took 5 ± 9 minutes per case. Multivariable analysis showed that LA intra-atrial dyssynchrony was independently associated with LA-LGE. In addition, LA intra-atrial dyssynchrony was significantly greater in patients with persistent AF than those with paroxysmal AF. In contrast, there was no significant difference in LA-LGE between patients with persistent and paroxysmal AF. LA intra-atrial dyssynchrony showed excellent reproducibility and its analysis was less time-consuming (5 ± 9 minutes) than the LA-LGE (60 ± 20 minutes). Conclusion: LA Intra-atrial dyssynchrony is a quick and reproducible index that is independently associated with LA-LGE to reflect the underlying tissue remodeling. Resumo Fundamento: Estudos recentes sugerem que o realce tardio com gadolínio (RTG) no átrio esquerdo (AE) pode quantificar a remodelação tecidual subjacente que abriga a fibrilação atrial (FA). No entanto, a quantificação do RTG-AE requer um trabalho intenso de aquisição por ressonância magnética e pós-processamento em centros experientes. A avaliação da dessincronia intra-atrial no AE é uma técnica de imagem emergente que prediz a recorrência da FA após ablação por cateter. Nós levantamos as hipóteses de que 1) a dessincronia intra-atrial está associada ao RTG-AE em pacientes com FA e 2) a dessincronia intra-atrial é maior em pacientes com FA persistente do que naqueles com FA paroxística. Método: Realizamos um estudo transversal comparando a dessincronia intra-atrial no AE e o RTG-AE em 146 pacientes com história de FA (60,0 ± 10,0 anos, 30,1% com FA não paroxística) submetidos à ressonância magnética cardíaca (RMC) durante ritmo sinusal antes da ablação da FA. Com utilização de RMC com tissue tracking, medimos o strain longitudinal do AE em cortes de duas e quatro câmaras. Definimos a dessincronia intra-atrial como o desvio padrão (DP) do tempo até o pico do strain longitudinal (DP-TPS, em %) e o DP do tempo até o pico do strain antes da contração atrial corrigido pela duração do ciclo (DP-TPSpreA, em %). Utilizamos a razão da intensidade da imagem (RIM) para quantificar o RTG-AE. Resultados: A análise da dessincronia intra-atrial levou 9 ± 5 minutos por caso. A análise multivariada mostrou que a dessincronia intra-atrial no AE esteve independentemente associada ao RTG-AE. Além disso, a dessincronia intra-atrial no AE foi significativamente maior em pacientes com FA persistente do que naqueles com FA paroxística. Por outro lado, não houve diferença significativa no RTG-AE entre pacientes com FA persistente e paroxística. A dessincronia intra-atrial no AE mostrou excelente reprodutibilidade e sua análise foi menos demorada (5 ± 9 minutos) do que o RTG-AE (60 ± 20 minutos). Conclusão: A dessincronia intra-atrial no AE é um índice rápido, reprodutível e independentemente associado ao RTG-AE para indicar remodelação tecidual subjacente. (Arq Bras Cardiol. 2019; 112(4):441-450)

Background: Arrhythmogenic right ventricular cardiomyopathy is an inherited cardiomyopathy characterized by fibrofatty replacement of right ventricular myocardium resulting in reentrant ventricular tachycardia (VT). Cardiac magnetic resonance imaging (CMR) can noninvasively measure regional abnormalities using tissue-tracking strain as well as late gadolinium enhancement (LGE). In this study, we examine arrhythmogenic substrate using regional CMR strain, LGE, and electroanatomic mapping (EAM) in arrhythmogenic right ventricular cardiomyopathy patients presenting for VT ablation. Methods and Results: Twenty-one patients underwent right ventricular endocardial EAM, whereas 17 underwent epicardial EAM, to detect dense scar (P P =0.001), and at VT culprit sites (−7.4±3.7 versus −10.1±4.1; P P Conclusions: Regional myocardial strain on cine CMR improves detection of arrhythmogenic VT substrate compared with LGE. This may enhance diagnostic accuracy of CMR in arrhythmogenic right ventricular cardiomyopathy without the need for invasive procedures and facilitate the planning of VT ablation procedures.

Focal impulse and rotor mapping (FIRM) involves intracardiac detection and catheter ablation of re-entrant drivers (RDs), some of which may contribute to arrhythmia perpetuation in persistent atrial fibrillation (PsAF). Patient-specific computational models derived from late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) has the potential to non-invasively identify all areas of the fibrotic substrate where RDs could potentially be sustained, including locations where RDs may not manifest during mapped AF episodes. The objective of this study was to carry out multi-modal assessment of the arrhythmogenic propensity of the fibrotic substrate in PsAF patients by comparing locations of RD-harboring regions found in simulations and detected by FIRM (RDsim and RDFIRM) and analyze implications for ablation strategies predicated on targeting RDs. For 11 PsAF patients who underwent pre-procedure LGE-MRI and FIRM-guided ablation, we retrospectively simulated AF in individualized atrial models, with geometry and fibrosis distribution reconstructed from pre-ablation LGE-MRI scans, and identified RDsim sites. Regions harboring RDsim and RDFIRM were compared. RDsim were found in 38 atrial regions (median [inter-quartile range (IQR)] = 4 [3; 4] per model). RDFIRM were identified and subsequently ablated in 24 atrial regions (2 [1; 3] per patient), which was significantly fewer than the number of RDsim-harboring regions in corresponding models (p < 0.05). Computational modeling predicted RDsim in 20 of 24 (83%) atrial regions identified as RDFIRM-harboring during clinical mapping. In a large number of cases, we uncovered RDsim-harboring regions in which RDFIRM were never observed (18/22 regions that differed between the two modalities; 82%); we termed such cases “latent” RDsim sites. During follow-up (230 [180; 326] days), AF recurrence occurred in 7/11 (64%) individuals. Interestingly, latent RDsim sites were observed in all seven computational models corresponding to patients who experienced recurrent AF (2 [2; 2] per patient); in contrast, latent RDsim sites were only discovered in two of four patients who were free from AF during follow-up (0.5 [0; 1.5] per patient; p < 0.05 vs. patients with AF recurrence). We conclude that substrate-based ablation based on computational modeling could improve outcomes.

BACKGROUND: Bilateral thoracoscopic stellectomy has antiarrhythmic effects, however, the procedure is invasive with associated morbidity. Sympathetic nerves from both stellate ganglia form the deep cardiac plexus (CP) in the aortopulmonary window (APW), anterior to the trachea. OBJECTIVE: To demonstrate a novel and minimally invasive transtracheal approach to block the cardiac plexus in porcine models. METHODS: In 12 Yorkshire pigs, right (RSG) and left (LSG) stellate ganglia were electrically stimulated and sympathetic baseline response recorded (hemodynamic parameters and T wave pattern). APW was accessed transtracheally with endobronchial ultrasound (EBUS) guidance and local stimulation of CP confirmed the location. Injection of 1% lidocaine (n=10) or saline solution (n=2) was performed and RSG and LSG responses were re-evaluated and compared with baseline. RESULTS: Transtracheal lidocaine injection into the CP successfully blocked bilateral sympathetic induced changes (%) in T wave amplitude (282.8±152.2 vs 20.1±16.5%, p

We thank Penela et al for their comments and congratulate them for their achievements and unique work in the field. Starting in 2005, our group, as well as others, described the utility of cardiac magnetic resonance for ventricular tachycardia substrate identification in the setting of structural heart disease,1 …

Bipolar voltage mapping, as part of atrial fibrillation (AF) ablation, is traditionally performed in a point-by-point (PBP) approach using single-tip ablation catheters. Alternative techniques for fibrosis-delineation include fast-anatomical mapping (FAM) with multi-electrode circular catheters, and late gadolinium-enhanced magnetic-resonance imaging (LGE-MRI). The correlation between PBP, FAM, and LGE-MRI fibrosis assessment is unknown.In this study, we examined AF substrate using different modalities (PBP, FAM, and LGE-MRI mapping) in patients presenting for an AF ablation.LGE-MRI was performed pre-ablation in 26 patients (73% males, age 63±8years). 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 co-registered to LGE-MRI.Mean bipolar voltage for all 19,087 FAM voltage points was 0.88±1.27mV and average IIR was 1.08±0.18. In an adjusted mixed-effects model, each unit increase in local IIR was associated with 57% decrease in bipolar voltage (p0.0001). IIR of0.74 corresponded to bipolar voltage0.5 mV. A total of 1554 PBP-mapping points were matched to the nearest FAM-point. In an adjusted mixed-effects model, log-FAM bipolar voltage was significantly associated with log-PBP bipolar voltage (ß=0.36, p0.0001). At low-voltages, FAM-mapping distribution was shifted to the left compared to PBP-mapping; at intermediate voltages, FAM and PBP voltages were overlapping; and at high voltages, FAM exceeded PBP-voltages.LGE-MRI, FAM and PBP-mapping show good correlation in delineating electro-anatomical AF substrate. Each approach has fundamental technical characteristics, the awareness of which allows proper assessment of atrial fibrosis.

The aims of this study were to: 1) use a novel method of late gadolinium enhancement (LGE) quantification that uses normalized intensity measures to confirm the association between LGE extent and atrial fibrillation (AF) recurrence following ablation; and 2) examine the presence of interaction and effect modification between LGE and AF persistence.Recurrent AF after catheter ablation has been reported to associate with the baseline extent of left atrial LGE on cardiac magnetic resonance. Traditional methods for measurement of intensity lack an objective threshold for quantification and interpatient comparisons of LGE.The cohort included 165 participants (mean age 60.0 ± 10.2 years, 77% men, 57% with persistent AF) who underwent initial AF ablation. The association of baseline LGE extent with AF recurrence was examined using multivariable Cox proportional hazards models. Multiplicative and additive interactions between AF type and LGE extent were examined.During 10.2 ± 5.7 months of follow-up, 63 patients (38.2%) experienced AF recurrence. Baseline LGE extent was independently associated with AF recurrence after adjusting for confounders (hazard ratio: 1.5 per 10% increased LGE; p 0.001). The hazard ratio for AF recurrence progressively increased as a function of LGE. The magnitude of association between LGE35% and AF recurrence was greater among patients with persistent AF (hazard ratio: 6.5 [p = 0.001] vs. 3.6 [p = 0.001]); however, there was no evidence for statistical interaction.Regardless of AF persistence at baseline, participants with LGE ≤35% have favorable outcomes, whereas those with LGE35% have a higher rate of AF recurrence in the first year after ablation. These findings suggest a role for: 1) patient selection for AF ablation using LGE extent; and 2) substrate modification in addition to pulmonary vein isolation in patients with LGE extent exceeding 35% of left atrial myocardium.

Symptomatic left atrial (LA) flutter (LAFL) is common after atrial fibrillation (AF) ablation.The purpose of this study was to examine the association of baseline LA function with incident LAFL after AF ablation.The source cohort included 216 patients with cardiac magnetic resonance (CMR) before initial AF ablation between 2010 and 2013. Patients who underwent cryoballoon or laser ablation, patients with AF during CMR, and those with suboptimal CMR, or missing follow-up data were excluded. Baseline LA volume and function were assessed by feature-tracking CMR analysis.The final cohort included 119 patients (mean age 58.9 ± 11 years; 76.5% men; 70.6% patients with paroxysmal AF). During a median follow-up of 421 days (interquartile range 235-751 days), 22 patients (18.5%) had incident LAFL. Baseline LA volume was similar between the 2 groups. In contrast, baseline reservoir, conduit, and contractile function of the LA were significantly impaired in patients with incident LAFL. Baseline global peak longitudinal atrial strain (PLAS)22.65% predicted incident LAFL with 86% sensitivity and 68% specificity (C statistic 0.76). In a multivariable model adjusting for age, heart failure, and LA volume, PLAS (hazard ratio 0.9 per % increase in PLAS; P = .003) and LA linear lesions (hazard ratio 2.94; P = .020) were independently associated with incident LAFL. The coexistence of PLAS22.65% and linear lesions was associated with 9-fold increased hazard of incident LAFL.Baseline LA function and linear lesions were independently associated with incident LAFL after AF ablation. Linear lesions should be limited to selected cases, especially in patients with impaired LA function.

Background Catheter ablation utilizing radiofrequency (RF), Cryothermal (Cryo), or Laser energy is effective for treatment of atrial fibrillation (AF). Late gadolinium enhancement magnetic resonance imaging (LGE-MRI) has been used to estimate the burden of left atrial (LA) fibrosis, but no data exist regarding structural changes following each modality. We sought to compare the baseline to postprocedure change in LA scar burden following RF, Cryo, or Laser ablation for treatment of AF. Methods Seventeen patients with AF underwent initial pulmonary vein (PV) isolation (PVI) using RF (n = 7), Cryo (n = 5), and Laser (n = 5). LGE-MRI was performed prior to and at 24 hours and 3 months after PVI. Results In a linear mixed-effects model, accounting for intrapatient clustering of data and interpatient differences in baseline scar, LGE extent was significantly increased at 24 hours postablation (+14.6 ± 1.9% of LA myocardium, P < 0.001), and remained stable from 24 hours to 3 months (+0.12 ± 1.9%, P = 0.951). There was no statistically significant difference between the postablation scar extent among ablation modalities when compared to RF (Cryo +4.5 ± 3.0%, P = 0.123; Laser −3.2 ± 3.0%, P = 0.291). The PV antral LGE intensity was increased by 25.1 ± 3.8% (P

Mercury affects the nervous system and has been implicated in altering heart rhythm and function. We sought to better define its role in modulating heart rate variability, a well-known marker of cardiac autonomic function.This is a systematic review study.We searched PubMed, Embase, TOXLINE, and DART databases without language restriction. We report findings as a qualitative systematic review because heterogeneity in study design and assessment of exposures and outcomes across studies, as well as other methodological limitations of the literature, precluded a quantitative meta-analysis.We identified 12 studies of mercury exposure and heart rate variability in human populations (ten studies involving primarily environmental methylmercury exposure and two studies involving occupational exposure to inorganic mercury) conducted in Japan, the Faroe Islands, Canada, Korea, French Polynesia, Finland, and Egypt. The association of prenatal mercury exposure with lower high-frequency band scores (thought to reflect parasympathetic activity) in several studies, in particular the inverse association of cord blood mercury levels with the coefficient of variation of the R-R intervals and with low-frequency and high-frequency bands at 14 years of age in the Faroe Islands birth cohort study, suggests that early mercury exposure could have a long-lasting effect on cardiac parasympathetic activity. Studies with later environmental exposures to mercury in children or in adults were heterogeneous and did not show consistent associations.The evidence was too limited to draw firm causal inferences. Additional research is needed to elucidate the effects of mercury on cardiac autonomic function, particularly as early-life exposures might have lasting impacts on cardiac parasympathetic function.

Despite the revolutionary advancements in the past 3 decades in the treatment of ventricular tachyarrhythmias with device-based therapy, sudden cardiac death (SCD) remains an enormous public health burden. Survivors of SCD are generally at high risk for recurrent events. The clinical management of such patients requires a multidisciplinary approach from postresuscitative care to a thorough cardiovascular investigation in an attempt to identify the underlying substrate, with potential to eliminate or modify the triggers through catheter ablation and ultimately an implantable cardioverter-defibrillator (ICD) for prompt treatment of recurrences in those at risk. Early recognition of low left ventricular ejection fraction as a strong predictor of death and association of ventricular arrhythmias with sudden death led to significant investigation with antiarrhythmic drugs. The lack of efficacy and the proarrhythmic effects of drugs catalyzed the development and investigation of the ICD through several major clinical trials that proved the efficacy of ICD as a bedrock tool to detect and promptly treat life-threatening arrhythmias. The ICD therapy is routinely used for primary prevention of SCD in patients with cardiomyopathy and high risk inherited arrhythmic conditions and secondary prevention in survivors of sudden cardiac arrest. This compendium will review the clinical management of those surviving SCD and discuss landmark studies of antiarrhythmic drugs, ICD, and cardiac resynchronization therapy in the primary and secondary prevention of SCD.