Can Fat Deposition After Myocardial Infarction Alter the Performance of RF Catheter Ablation of Scar-Related Ventricular Tachycardia?: Results from a Computer Modeling Study

Effect of Fat Deposition on the Performance in RF Ablation IntroductionThe outcomes of catheter ablation of scar-mediated ventricular tachycardia (VT) remain far from perfect. The presence of fat as a component of the underlying substrate for scar-mediated VT could be relevant since this entity can seriously impede the passage of RF current due to its low electrical conductivity. Methods and ResultsComputer models of RF ablation were built in order to investigate the means by which the spatial heterogeneity of different tissues represented within the ventricular infarct zone, including the viable myocardium, fibrous tissue, and fat, could influence temperature distributions during RF ablation. The results demonstrated that spatial distributions of different tissue types significantly alter the density of electrical current largely as a result of fat impeding the passage of current. However, the thermal lesions appear minimally unaffected by this phenomenon, with variations in depth of approximate to 1 mm. ConclusionWhile during RF ablation of scar-related ventricular tachycardia differences in tissue characteristics may affect the density of electrical current on a small-scale, overall this does not appear to significantly impact the size of the created thermal lesions.This work was supported by the Spanish "Plan Estatal de Investigacion, Desarrollo e Innovacion Orientada a los Retos de la Sociedad" under Grant TEC2014-52383-C3 (TEC2014-52383-C3-1-R).Pérez, JJ.; D'avila, A.; Aryana, A.; Trujillo Guillen, M.; Berjano, E. (2016). Can Fat Deposition After Myocardial Infarction Alter the Performance of RF Catheter Ablation of Scar-Related Ventricular Tachycardia?: Results from a Computer Modeling Study. Journal of Cardiovascular Electrophysiology. 27(8):947-952. https://doi.org/10.1111/jce.13006S947952278Aryana, A., & d’ Avila, A. (2014). 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Circulation, 126(17), 2065-2072. doi:10.1161/circulationaha.112.112540Sasaki, T., Calkins, H., Miller, C. F., Zviman, M. M., Zipunnikov, V., Arai, T., … Zimmerman, S. L. (2015). New insight into scar-related ventricular tachycardia circuits in ischemic cardiomyopathy: Fat deposition after myocardial infarction on computed tomography--A pilot study. Heart Rhythm, 12(7), 1508-1518. doi:10.1016/j.hrthm.2015.03.041Goldfarb, J. W., Roth, M., & Han, J. (2009). Myocardial Fat Deposition after Left Ventricular Myocardial Infarction: Assessment by Using MR Water-Fat Separation Imaging. Radiology, 253(1), 65-73. doi:10.1148/radiol.2532082290Ichikawa, Y., Kitagawa, K., Chino, S., Ishida, M., Matsuoka, K., Tanigawa, T., … Sakuma, H. (2009). Adipose Tissue Detected by Multislice Computed Tomography in Patients After Myocardial Infarction. JACC: Cardiovascular Imaging, 2(5), 548-555. doi:10.1016/j.jcmg.2009.01.010Su, L., Siegel, J. E., & Fishbein, M. C. (2004). Adipose tissue in myocardial infarction. Cardiovascular Pathology, 13(2), 98-102. doi:10.1016/s1054-8807(03)00134-0Suárez, A. G., Hornero, F., & Berjano, E. J. (2010). Mathematical Modeling of Epicardial RF Ablation of Atrial Tissue with Overlying Epicardial Fat. The Open Biomedical Engineering Journal, 4(1), 47-55. doi:10.2174/1874120701004020047PÉREZ, J. J., D’AVILA, A., ARYANA, A., & BERJANO, E. (2015). Electrical and Thermal Effects of Esophageal Temperature Probes on Radiofrequency Catheter Ablation of Atrial Fibrillation: Results from a Computational Modeling Study. Journal of Cardiovascular Electrophysiology, 26(5), 556-564. doi:10.1111/jce.12630Berjano, E. J. (2006). BioMedical Engineering OnLine, 5(1), 24. doi:10.1186/1475-925x-5-24Hasgall PA Di Gennaro F Baumgartner C Neufeld E Gosselin MC Payne D Klingenböck A Kuster N 10.13099/VIP21000-03-0 www.itis.ethz.ch/databaseGonzalez-Suarez, A., & Berjano, E. (2016). 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Cardiac Resynchronization Therapy: Who Benefits?

Background: Cardiac resynchronization therapy (CRT) has been well established in multiple large trials to improve symptoms, hospitalizations, reverse remodeling, and mortality in well-selected patients with heart failure when used in addition to optimal medical therapy. Updated consensus guidelines outline patients in whom such therapy is most likely to result in substantial benefit. However, pooled data have demonstrated that only approximately 70% of patients who qualify for CRT based on current indications actually respond favorably. In addition, current guidelines are based on outcomes from the carefully selected patients enrolled in clinical trials, and almost certainly fail to include all patients who might benefit from CRT. Findings: The identification of patients most likely to benefit from CRT requires consideration of factors beyond these standard criteria, QRS morphology with particular consideration in patients with left bundle-branch block pattern, extent of QRS prolongation, etiology of cardiomyopathy, rhythm, and whether the patient requires or will eventually need antibradycardia pacing. In addition, the baseline severity of functional impairment may influence the type of benefit to be expected from CRT; for example, New York Heart Association class I patients may derive long-term benefit in cardiac structure and function, but no benefit in symptoms or hospitalizations can be reasonably expected. In contrast, certain New York Heart Association class IV patients may be too sick to realize long-term mortality benefits from CRT, but improvements in hemodynamic profile and functional capacity may represent vital advances in this population. Conclusion: This review evaluates the evidence regarding the various factors that can predict positive or even detrimental responses to CRT, to help better determine who benefits most from this evolving therapy

Quality indicators for the care and outcomes of adults with atrial fibrillation

Aims To develop quality indicators (QIs) that may be used to evaluate the quality of care and outcomes for adults with atrial fibrillation (AF). Methods and results We followed the ESC methodology for QI development. This methodology involved (i) the identification of the domains of AF care for the diagnosis and management of AF (by a group of experts including members of the ESC Clinical Practice Guidelines Task Force for AF); (ii) the construction of candidate QIs (including a systematic review of the literature); and (iii) the selection of the final set of QIs (using a modified Delphi method). Six domains of care for the diagnosis and management of AF were identified: (i) Patient assessment (baseline and follow-up), (ii) Anticoagulation therapy, (iii) Rate control strategy, (iv) Rhythm control strategy, (v) Risk factor management, and (vi) Outcomes measures, including patient-reported outcome measures (PROMs). In total, 17 main and 17 secondary QIs, which covered all six domains of care for the diagnosis and management of AF, were selected. The outcome domain included measures on the consequences and treatment of AF, as well as PROMs. Conclusion This document defines six domains of AF care (patient assessment, anticoagulation, rate control, rhythm control, risk factor management, and outcomes), and provides 17 main and 17 secondary QIs for the diagnosis and management of AF. It is anticipated that implementation of these QIs will improve the quality of AF care

A principal component meta-analysis on multiple anthropometric traits identifies novel loci for body shape

Large consortia have revealed hundreds of genetic loci associated with anthropometric traits, one trait at a time. We examined whether genetic variants affect body shape as a composite phenotype that is represented by a combination of anthropometric traits. We developed an approach that calculates averaged PCs (AvPCs) representing body shape derived from six anthropometric traits (body mass index, height, weight, waist and hip circumference, waist-to-hip ratio). The first four AvPCs explain >99% of the variability, are heritable, and associate with cardiometabolic outcomes. We performed genome-wide association analyses for each body shape composite phenotype across 65 studies and meta-analysed summary statistics. We identify six novel loci: LEMD2 and CD47 for AvPC1, RPS6KA5/C14orf159 and GANAB for AvPC3, and ARL15 and ANP32 for AvPC4. Our findings highlight the value of using multiple traits to define complex phenotypes for discovery, which are not captured by single-trait analyses, and may shed light onto new pathways.Peer reviewe

Adding Mobility to a Fire Products Collector

Tyco's laboratories provided a typical lab scenario setup for a case study of the application of a mobile fire products collector. For the purpose of the study, the fire products collector system design was subdivided into four primary components used for typical laboratory testing requirements: the hood, the duct, the probes and the instrumentation cabinet. The sampling portion of the duct and the mobile cabinet with all of the instrumentation are able to be moved and can be shared between the two different test bays in order to reduce the cost significantly. Through creating a mobile version of the fire products collector, the cost efficiency of the system was improved by approximately 66%

Flocculation of fine fluorite particles with Corynebacterium xerosis and commercial long chain polymers

This work aimed to study, comparatively, the flocculation of fluorite particles with Corynebacterium xerosis cells and three commercial long chain polymers. Best flocculation results were obtained with cells of C. xerosis and with an anionic polyacrylamide. Both were effective in solids removal and water clarification, although flocculation with C. xerosis cells requires a higher dosage of reagent per mass unit of processed ore

Painful left bundle branch block syndrome treated with his bundle pacing

This is a case report of a patient with painful LBBB Syndrome that responded favorably to His Bundle Pacing. This syndrome is largely under recognized despite 50 reports in the literature over the last 60 years. Both diagnosis and treatment are not well defined and represent a major challenge in patients with this entity. Right ventricular pacing has been attempted with inconsistent efficacy outcomes. We report for the first-time complete resolution of chest pain with His bundle pacing. HBP provides a promising alternative pacing option that might provide symptom resolution to patients with a painful LBBB syndrome

Flocculation of fine fluorite particles with Corynebacterium xerosis and commercial long chain polymers

This work aimed to study, comparatively, the flocculation of fluorite particles with Corynebacterium xerosis cells and three commercial long chain polymers. Best flocculation results were obtained with cells of C. xerosis and with an anionic polyacrylamide. Both were effective in solids removal and water clarification, although flocculation with C. xerosis cells requires a higher dosage of reagent per mass unit of processed ore

Acute and chronic effects of epicardial radiofrequency applications delivered on epicardial coronary arteries

Epicardial coronary injury is by far the most feared complication of epicardial ablation. Little information is available regarding the chronic effects of delivering radiofrequency in the vicinity of large coronary vessels, and the long-term impact of this approach for mapping and ablation on epicardial vessel integrity is poorly understood. Therefore, the aim of this study was to characterize the acute and chronic histopathologic changes produced by in vivo epicardial pulses of radiofrequency ablation on coronary artery of porcine hearts. Seven pigs underwent a left thoracotomy. The catheter was sutured adjacent to the left anterior descending artery and left circumflex artery, and 20 pulses of radiofrequency energy were applied. Radiofrequency lesions located no more than 1 mm of the vessel were used for this analysis. Three animals were euthanized 20 days (acute phase) after the procedure and 4 animals after 70 days (chronic phase). The following parameters were obtained in each vessel analyzed: (1) internal and external perimeter; (2) vessel wall thickness; (3) tunica media thickness, and (4) tunica intima thickness. The presence of adipose tissue around the coronary arteries, the distance between the artery and the epicardium, and the anatomic relationship of the artery with the coronary vein was also documented for each section. Sixteen of 20 (80%) sections analyzed, showed intimal thickening with a mean of 0.18 ± 0.14 mm compared with 0.13 ± 0.16 mm in the acute phase (P = 0.331). The mean tunica media thickness was 0.25 ± 0.10 mm in the chronic phase animals compared with 0.18 ± 0.03 mm in the acute phase animals (P = 0.021). A clear protective effect of pericardial fat and coronary veins was also present. A positive correlation between depth of radiofrequency lesion and the degree of vessel injury expressed as intimal and media thickening (P = 0.001) was present. A negative correlation was identified (r = -0.83; P = 0.002) between intimal thickening and distance between epicardium and coronary artery. In this porcine model of in vivo epicardial radiofrequency ablation in proximity to coronary arteries leads to acute and chronic histopathologic changes characterized by tunica intima and media thickening, with replacement of smooth muscle cells with extracellular matrix, but no significant stenosis was observed up to 70 days after the ablation. The absence of acute coronary occlusion or injury does not preclude subsequent significant arterial damage, which frequently occurs when epicardial radiofrequency applications are delivered in close vicinity to the vessels