Publications by authors named "Buch E"

149 Publications

Hybrid surgical vs percutaneous access epicardial ventricular tachycardia ablation.

Heart Rhythm 2018 04 11;15(4):512-519. Epub 2017 Nov 11.

UCLA Cardiac Arrhythmia Center, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California. Electronic address:

Background: There is limited experience of surgical epicardial access in the contemporary era of ventricular tachycardia ablation after cardiac surgery.

Objectives: The purpose of this study was to describe our institutional experience with surgical epicardial access and the influence of surgical approach and compare outcomes with those of a propensity-matched percutaneous epicardial access control group.

Methods: We performed a retrospective study of consecutive surgical epicardial ventricular tachycardia (VT) ablation cases from a single center. Surgical cases were propensity-matched to percutaneous epicardial ablation controls and short-term and long-term outcomes were compared.

Results: Between 2004 and 2016, 38 patients underwent 40 surgical epicardial access procedures (subxiphoid, n = 22; thoracotomy, n = 18). The commonest indication was prior coronary artery bypass grafting (45%), valve surgery (22%), or ventricular assist device (VAD) (10%). The mean procedure time was 444 minutes (standard deviation, 107 minutes). Mapped epicardial geometry area was 149 cm (interquartile range 182 cm), which comprised 36% of the mapped epicardial geometric area of a percutaneous control group. Subxiphoid access gave preferential access to the inferior and inferolateral left ventricular segments and was less frequently able to access the anterior, anterolateral, and apical segments compared with a thoracotomy approach. When compared with results from a propensity-matched percutaneous-access group, short-term outcomes, complication rates, and 1-year survival free from a combined end point of VT recurrence, death, or transplantation were not statistically different.

Conclusions: Surgical epicardial access after cardiac surgery for ablation of VT in patients with careful preprocedure evaluation can be performed with acceptable safety with no statistical difference in long-term outcomes compared with a propensity-matched percutaneous epicardial cohort. The region of left ventricular epicardium that can be mapped is limited compared with that of percutaneous cases and is determined by the surgical approach.
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http://dx.doi.org/10.1016/j.hrthm.2017.11.009DOI Listing
April 2018

Longitudinal Structural and Functional Differences Between Proportional and Poor Motor Recovery After Stroke.

Neurorehabil Neural Repair 2017 Dec 12;31(12):1029-1041. Epub 2017 Nov 12.

3 National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.

Background: Evolution of motor function during the first months after stroke is stereotypically bifurcated, consisting of either recovery to about 70% of maximum possible improvement ("proportional recovery, PROP") or in little to no improvement ("poor recovery, POOR"). There is currently no evidence that any rehabilitation treatment will prevent POOR and favor PROP.

Objective: To perform a longitudinal and multimodal assessment of functional and structural changes in brain organization associated with PROP.

Methods: Fugl-Meyer Assessments of the upper extremity and high-density electroencephalography (EEG) were obtained from 63 patients, diffusion tensor imaging from 46 patients, at 2 and 4 weeks (T0) and at 3 months (T1) after stroke onset.

Results: We confirmed the presence of 2 distinct recovery patterns (PROP and POOR) in our sample. At T0, PROP patients had greater integrity of the corticospinal tract (CST) and greater EEG functional connectivity (FC) between the affected hemisphere and rest of the brain, in particular between the ventral premotor and the primary motor cortex. POOR patients suffered from degradation of corticocortical and corticofugal fiber tracts in the affected hemisphere between T0 and T1, which was not observed in PROP patients. Better initial CST integrity correlated with greater initial global FC, which was in turn associated with less white matter degradation between T0 and T1.

Conclusions: These findings suggest links between initial CST integrity, systems-level cortical network plasticity, reduction of white matter atrophy, and clinical motor recovery after stroke. This identifies candidate treatment targets.
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http://dx.doi.org/10.1177/1545968317740634DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6368856PMC
December 2017

Incidence and significance of adhesions encountered during epicardial mapping and ablation of ventricular tachycardia in patients with no history of prior cardiac surgery or pericarditis.

Heart Rhythm 2018 01 14;15(1):65-74. Epub 2017 Sep 14.

University of California, Los Angeles, Cardiac Arrhythmia Center, David Geffen School of Medicine at UCLA, Los Angeles, California. Electronic address:

Background: Pericardial adhesions can prevent epicardial access and restrict catheter movement during mapping and ablation of ventricular tachycardia (VT). The incidence of adhesions in patients without prior cardiac surgery or clinically evident pericarditis is not known.

Objective: To describe the incidence of pericardial adhesions and explore their impact in patients without prior cardiac surgery or pericarditis.

Methods: A retrospective search of our ablation database containing patients who underwent epicardial ablation for VT was undertaken. Adhesions were diagnosed with routine contrast pericardiography after pericardial entry. Demographics and long-term outcomes were compared between patients with and without adhesions.

Results: Between 2004 and 2016, successful epicardial entry was achieved in 188 of 192 attempts (98%). In 155 first-time epicardial access attempts, pericardial adhesions were diagnosed in 13 (8%). When comparing baseline demographics, there was no significant difference. However, adhesions tended to occur more frequently with severe renal impairment (2% of patients without adhesions vs 15% of patients with adhesions, P = .07). No patient with a structurally normal heart had adhesions present. Adhesions were associated with limited epicardial mapping (3% of patients without adhesions vs 85% of patients with adhesions, P < .001) and lower short-term procedural success (68% of patients without adhesions vs 46% of patients with adhesions, P = .02), but complication rates were similar. The presence of adhesions did not translate into lower VT-free survival (P = .64) or freedom from a combined end point of VT recurrence, death, or transplant at 1 year (P = .93).

Conclusion: Adhesions may be unexpectedly encountered in patients without prior cardiac surgery or pericarditis. When present, they can limit mapping and may be associated with lower short-term success. Larger studies are required to determine their impact on long-term outcomes.
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http://dx.doi.org/10.1016/j.hrthm.2017.09.007DOI Listing
January 2018

'Runaway' vagal nerve stimulator: a case of cyclic asystole.

HeartRhythm Case Rep 2016 Sep 28;2(5):388-390. Epub 2016 Jun 28.

UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California.

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http://dx.doi.org/10.1016/j.hrcr.2016.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5419945PMC
September 2016

Could less be more in catheter ablation for persistent atrial fibrillation? Pulmonary vein isolation reconsidered.

Heart Rhythm 2017 05;14(5):668-669

UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA, Los Angeles, California.

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http://dx.doi.org/10.1016/j.hrthm.2017.01.024DOI Listing
May 2017

Effects of tDCS on motor learning and memory formation: A consensus and critical position paper.

Clin Neurophysiol 2017 Apr 29;128(4):589-603. Epub 2017 Jan 29.

Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA. Electronic address:

Motor skills are required for activities of daily living. Transcranial direct current stimulation (tDCS) applied in association with motor skill learning has been investigated as a tool for enhancing training effects in health and disease. Here, we review the published literature investigating whether tDCS can facilitate the acquisition, retention or adaptation of motor skills. Work in multiple laboratories is underway to develop a mechanistic understanding of tDCS effects on different forms of learning and to optimize stimulation protocols. Efforts are required to improve reproducibility and standardization. Overall, reproducibility remains to be fully tested, effect sizes with present techniques vary over a wide range, and the basis of observed inter-individual variability in tDCS effects is incompletely understood. It is recommended that future studies explicitly state in the Methods the exploratory (hypothesis-generating) or hypothesis-driven (confirmatory) nature of the experimental designs. General research practices could be improved with prospective pre-registration of hypothesis-based investigations, more emphasis on the detailed description of methods (including all pertinent details to enable future modeling of induced current and experimental replication), and use of post-publication open data repositories. A checklist is proposed for reporting tDCS investigations in a way that can improve efforts to assess reproducibility.
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http://dx.doi.org/10.1016/j.clinph.2017.01.004DOI Listing
April 2017

The continuing search for patient-specific atrial fibrillation ablation targets: Need for rigorously verified and independently replicated data.

Heart Rhythm 2016 12 24;13(12):2331-2332. Epub 2016 Aug 24.

Loma Linda University Medical Center, Loma Linda, California.

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http://dx.doi.org/10.1016/j.hrthm.2016.08.033DOI Listing
December 2016

3D-printed head models for navigated non-invasive brain stimulation.

Clin Neurophysiol 2016 10 25;127(10):3341-2. Epub 2016 Aug 25.

Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, United States. Electronic address:

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http://dx.doi.org/10.1016/j.clinph.2016.08.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5108057PMC
October 2016

Predicting motor improvement after stroke with clinical assessment and diffusion tensor imaging.

Neurology 2016 05 29;86(20):1924-5. Epub 2016 Apr 29.

From the Human Cortical Physiology and Neurorehabilitation Section (E.R.B., L.G.C.), NINDS, NIH, Bethesda, MD; and University Hospital and University of Geneva (S.R., P.N., A.S., A.G.G.), Switzerland.

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http://dx.doi.org/10.1212/WNL.0000000000002675DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4873682PMC
May 2016

Plasticity of Sensorimotor Networks: Multiple Overlapping Mechanisms.

Neuroscientist 2017 04 8;23(2):185-196. Epub 2016 Jul 8.

1 National Institute of Neurological Disorders and Stroke (NINDS), Bethesda, MD, USA.

Redundancy is an important feature of the motor system, as abundant degrees of freedom are prominent at every level of organization across the central and peripheral nervous systems, and musculoskeletal system. This basic feature results in a system that is both flexible and robust, and which can be sustainably adapted through plasticity mechanisms in response to intrinsic organismal changes and dynamic environments. While much early work of motor system organization has focused on synaptic-based plasticity processes that are driven via experience, recent investigations of neuron-glia interactions, epigenetic mechanisms and large-scale network dynamics have revealed a plethora of plasticity mechanisms that support motor system organization across multiple, overlapping spatial and temporal scales. Furthermore, an important role of these mechanisms is the regulation of intrinsic variability. Here, we review several of these mechanisms and discuss their potential role in neurorehabilitation.
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http://dx.doi.org/10.1177/1073858416638641DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5108685PMC
April 2017

Long-term clinical outcomes of focal impulse and rotor modulation for treatment of atrial fibrillation: A multicenter experience.

Heart Rhythm 2016 Mar 21;13(3):636-41. Epub 2015 Oct 21.

UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA, Los Angeles, California.

Background: New approaches to ablation of atrial fibrillation (AF) include focal impulse and rotor modulation (FIRM). Studies of this technology with short-term follow-up have shown favorable outcomes.

Objective: The purpose of this study was to characterize the long-term results of FIRM ablation in a cohort of patients treated at 2 academic medical centers.

Methods: All FIRM-guided ablation procedures (n = 43) at UCLA Medical Center and Virginia Commonwealth University Medical Center performed between January 2012 and October 2013 were included for analysis. During AF, FIRM software constructed phase maps from unipolar atrial electrograms to identify putative AF sources. These sites were targeted for ablation, along with pulmonary vein isolation in 77% of patients.

Results: AF was paroxysmal in 56%, and 67% had prior AF ablation. All patients had rotors identified (mean 2.6 ± 1.2 per patient, 77% in LA). Prespecified acute procedural end-point was achieved in 47% of patients (n = 20): AF termination in 4, organization in 7, >10% slowing of AF cycle length in 9. Acute complications occurred in 4 patients (9.3%). At 18 ± 7 months of follow-up, 37% were free from documented recurrent AF after a 3-month blanking period; 21% were free from documented atrial tachyarrhythmias and off antiarrhythmic drugs. Multivariate analysis did not reveal any significant predictors of AF recurrence, including pattern of AF, acute procedural success, or prior failed ablation.

Conclusion: Long-term clinical results after FIRM ablation in this cohort of patients showed poor efficacy, different from previously published studies. Randomized studies are needed to evaluate the efficacy and clinical utility of this ablation approach for treating AF.
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http://dx.doi.org/10.1016/j.hrthm.2015.10.031DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4762742PMC
March 2016

Postponing Passage: Doorways, Distinctions, and the Thresholds of Personhood among Older Chicagoans.

Authors:
Elana D Buch

Ethos 2015 Mar;43(1):40-58

Assistant Professor of Anthropology at the University of Iowa.

This article analyzes the quotidian ways that older Chicagoans remade and traversed physical boundaries between their homes and the city beyond. In so doing, it explores how changing engagements with the environment impact social personhood in later life. In a context in which personhood is equated with independence, elders relying on paid care workers to remain in their homes found themselves at the threshold of social death. To sustain their independence and personhood, older Chicagoans sought to prevent spatial and social transitions using a range of everyday tactics and material practices located around the doorways of their homes. These liminal practices simultaneously reasserted racial, class, and other social distinctions between elders, home care workers and others, helping elders continue to occupy familiar subject positions. For these older adults, homes and their thresholds became a resource with which they resisted profound changes to their daily lives, subjectivities, and social personhood.
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http://dx.doi.org/10.1111/etho.12071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4577063PMC
March 2015

Catheter Ablation of Atrial Fibrillation: Advent of Second-Generation Technologies.

J Am Coll Cardiol 2015 Sep;66(12):1361-3

UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA, Los Angeles, California. Electronic address:

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http://dx.doi.org/10.1016/j.jacc.2015.07.056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4659817PMC
September 2015

Altered Human Memory Modification in the Presence of Normal Consolidation.

Cereb Cortex 2016 09 12;26(9):3828-3837. Epub 2015 Aug 12.

Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.

Following initial learning, the memory is stabilized by consolidation mechanisms, and subsequent modification of memory strength occurs via reconsolidation. Yet, it is not clear whether consolidation and memory modification are the same or different systems-level processes. Here, we report disrupted memory modification in the presence of normal consolidation of human motor memories, which relate to differences in lesioned brain structure after stroke. Furthermore, this behavioral dissociation was associated with macrostructural network architecture revealed by a graph-theoretical approach, and with white-matter microstructural integrity measured by diffusion-weighted MRI. Altered macrostructural network architecture and microstructural integrity of white-matter underlying critical nodes of the related network predicted disrupted memory modification. To the best of our knowledge, this provides the first evidence of mechanistic differences between consolidation, and subsequent memory modification through reconsolidation, in human procedural learning. These findings enable better understanding of these memory processes, which may guide interventional strategies to enhance brain function and resulting behavior.
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http://dx.doi.org/10.1093/cercor/bhv180DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5004751PMC
September 2016

Predicting postoperative atrial fibrillation using CHA2DS2-VASc scores.

J Surg Res 2015 Oct 18;198(2):267-72. Epub 2015 Apr 18.

Division of Cardiac Surgery, Department of Surgery, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California. Electronic address:

Background: Postoperative atrial fibrillation (POAF) is the most frequent complication of cardiac surgery and is associated with increased morbidity and mortality. Pharmacologic prophylaxis is the main method of preventing POAF but needs to be targeted to patients at high risk of developing POAF. The CHA2DS2-VASc scoring system is a clinical guideline for assessing ischemic stroke risk in patients with atrial fibrillation. The present study evaluated the utility of this scoring system in predicting the risk of developing de novo POAF in cardiac surgery patients.

Materials And Methods: A total of 2385 patients undergoing cardiac surgery at our institution from 2008-2014 were identified for analysis. Each patient was assigned a CHA2DS2-VASc score and placed into a low- (score of 0), intermediate- (1), or high-risk (≥2) group. A multivariate regression model was created to control for known risk factors of atrial fibrillation.

Results: POAF occurred in 380 of 2385 patients (15.9%). Mean CHA2DS2-VASc scores among patients with POAF and without POAF were 3.6 ± 1.7 and 2.8 ± 1.7, respectively (P < 0.0001). Using multivariate analysis, as a patient's CHA2DS2-VASc score rose from 0-9, the risk of developing POAF increased from 8.2%-42.3%. Each point increase was associated with higher odds of developing POAF (adjusted odds ratio, 1.27; 95% confidence interval, 1.18-1.36, P < 0.0001). Compared with low-risk patients, patients in the high-risk group were 5.21 times more likely to develop POAF (P < 0.0001).

Conclusions: The CHA2DS2-VASc algorithm is a simple risk-stratification tool that could be used to direct pharmacologic prophylaxis toward patients most likely to experience POAF.
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http://dx.doi.org/10.1016/j.jss.2015.04.047DOI Listing
October 2015

Quantitative analysis of localized sources identified by focal impulse and rotor modulation mapping in atrial fibrillation.

Circ Arrhythm Electrophysiol 2015 Jun 14;8(3):554-61. Epub 2015 Apr 14.

From the UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at University of California, Los Angeles (P.B., E.B., P.F., M.S., R.T., K.S., R.M.); and International Heart Institute, Loma Linda University Medical Center, CA (R.M.).

Background: New approaches to ablation of atrial fibrillation (AF) include focal impulse and rotor modulation (FIRM) mapping, and initial results reported with this technique have been favorable. We sought to independently evaluate the approach by analyzing quantitative characteristics of atrial electrograms used to identify rotors and describe acute procedural outcomes of FIRM-guided ablation.

Methods And Results: All FIRM-guided ablation procedures (n=24; 50% paroxysmal) at University of California, Los Angeles Medical Center were included for analysis. During AF, unipolar atrial electrograms collected from a 64-pole basket catheter were used to construct phase maps and identify putative AF sources. These sites were targeted for ablation, in conjunction with pulmonary vein isolation in most patients (n=19; 79%). All patients had rotors identified (mean, 2.3±0.9 per patient; 72% in left atrium). Prespecified acute procedural end point was achieved in 12 of 24 (50%) patients: AF termination (n=1), organization (n=3), or >10% slowing of AF cycle length (n=8). Basket electrodes were within 1 cm of 54% of left atrial surface area, and a mean of 31 electrodes per patient showed interpretable atrial electrograms. Offline analysis revealed no differences between rotor and distant sites in dominant frequency or Shannon entropy. Electroanatomic mapping showed no rotational activation at FIRM-identified rotor sites in 23 of 24 patients (96%).

Conclusions: FIRM-identified rotor sites did not exhibit quantitative atrial electrogram characteristics expected from rotors and did not differ quantitatively from surrounding tissue. Catheter ablation at these sites, in conjunction with pulmonary vein isolation, resulted in AF termination or organization in a minority of patients (4/24; 17%). Further validation of this approach is necessary.
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http://dx.doi.org/10.1161/CIRCEP.115.002721DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4655205PMC
June 2015

Relationship between sinus rhythm late activation zones and critical sites for scar-related ventricular tachycardia: systematic analysis of isochronal late activation mapping.

Circ Arrhythm Electrophysiol 2015 Apr 4;8(2):390-9. Epub 2015 Mar 4.

From the University of California at Los Angeles Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA.

Background: It is not known whether the most delayed late potentials are functionally most specific for scar-related ventricular tachycardia (VT) circuits.

Methods And Results: Isochronal late activation maps were constructed to display ventricular activation during sinus rhythm over 8 isochrones. Analysis was performed at successful VT termination sites and prospectively tested. Thirty-three patients with 47 scar-related VTs where a critical site was demonstrated by termination of VT during ablation were retrospectively analyzed. In those who underwent mapping of multiple surfaces, 90% of critical sites were on the surface that contained the latest late potential. However, only 11% of critical sites were localized to the latest isochrone (87.5%-100%) of ventricular activation. The median percentage of latest activation at critical sites was 78% at a distance from the latest isochrone of 18 mm. Sites critical to reentry were harbored in regions with slow conduction velocity, where 3 isochrones were present within a 1-cm radius. Ten consecutive patients underwent ablation prospectively guided by isochronal late activation maps, targeting concentric isochrones outside of the latest isochrone. Elimination of the targeted VT was achieved in 90%. Termination of VT was achieved in 6 patients at a mean ventricular activation percentage of 78%, with only 1 requiring ablation in the latest isochrone.

Conclusions: Late potentials identified in the latest isochrone of activation during sinus rhythm are infrequently correlated with successful ablation sites for VT. The targeting of slow conduction regions propagating into the latest zone of activation may be a novel and promising strategy for substrate modification.
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http://dx.doi.org/10.1161/CIRCEP.114.002637DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4695215PMC
April 2015

Causal manipulation of functional connectivity in a specific neural pathway during behaviour and at rest.

Elife 2015 Feb 9;4. Epub 2015 Feb 9.

Department of Experimental Psychology, Oxford University, Oxford, United Kingdom.

Correlations in brain activity between two areas (functional connectivity) have been shown to relate to their underlying structural connections. We examine the possibility that functional connectivity also reflects short-term changes in synaptic efficacy. We demonstrate that paired transcranial magnetic stimulation (TMS) near ventral premotor cortex (PMv) and primary motor cortex (M1) with a short 8-ms inter-pulse interval evoking synchronous pre- and post-synaptic activity and which strengthens interregional connectivity between the two areas in a pattern consistent with Hebbian plasticity, leads to increased functional connectivity between PMv and M1 as measured with functional magnetic resonance imaging (fMRI). Moreover, we show that strengthening connectivity between these nodes has effects on a wider network of areas, such as decreasing coupling in a parallel motor programming stream. A control experiment revealed that identical TMS pulses at identical frequencies caused no change in fMRI-measured functional connectivity when the inter-pulse-interval was too long for Hebbian-like plasticity.
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http://dx.doi.org/10.7554/eLife.04585DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4353194PMC
February 2015

Troubling gifts of care: vulnerable persons and threatening exchanges in Chicago's home care industry.

Authors:
Elana D Buch

Med Anthropol Q 2014 Dec 21;28(4):599-615. Epub 2014 Oct 21.

Department of Anthropology, University of Iowa.

By tracing the transformations of troubling exchanges in paid home care, this article examines how differently positioned individuals strive to build caring relations within potentially restrictive regimes of care. In paid home care in Chicago, older adults and their workers regularly participate in exchanges of money, time, and material goods. These gifts play a crucial role in building good care relationships that sustain participants' moral personhood. Amid widespread concern about vulnerable elders, home care agencies compete in a crowded marketplace by prohibiting these exchanges, even as they depend on them to strengthen relationships. Supervisors thus exercise discretion, sometimes reclassifying gift exchanges as punishable thefts. In this context, the commodification of care did not lead to the actual elimination of gift relations, but rather transformed gift relations into a suspicious and troublesome source of value.
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http://dx.doi.org/10.1111/maq.12126DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4576839PMC
December 2014

Catheter ablation of scar-based ventricular tachycardia: Relationship of procedure duration to outcomes and hospital mortality.

Heart Rhythm 2015 Jan 5;12(1):86-94. Epub 2014 Oct 5.

UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA, Los Angeles, California. Electronic address:

Background: Ablation has become an important option for treatment of ventricular tachycardia (VT). The influence of procedure duration on outcomes remains unexamined.

Objective: The purpose of this study was to determine the influence of procedure duration on outcomes and complications over an 8-year period

Methods: Patients referred for scar-mediated VT ablation from 2004 to 2011 were retrospectively analyzed. Procedure duration was defined as the time from the insertion of catheters through the femoral vein to the time of their withdrawal. Procedure duration was analyzed in relationship with baseline and intraoperative covariates, acute procedural outcomes, complications, and 6-month clinical outcomes.

Results: One hundred forty-eight patients underwent VT ablation with mean procedure duration of 5.7 ± 1.8 hours. VT recurrence and survival at 6 months were 46% and 82%, respectively, and were not associated with procedure duration. Hospital mortality increased with intraoperative intraaortic balloon pump insertion (adjusted odds ratio [OR] 13.7, 95% confidence interval [CI] 2.35-79.94, P = .004) and was improved with successful ablation of the clinical VT as a procedural end-point (adjusted OR 0.13, 95% Cl 0.03-0.54, P = .005). The association between procedure duration and hospital mortality remained after adjusting for significant baseline variables (adjusted OR 1.75, 95% CI 1.14-2.68, P = .0098) and intraoperative variables (adjusted OR 1.6, 95% CI 1.12-2.29, P = .0104).

Conclusion: Hospital mortality was significantly increased by unsuccessful clinical VT ablation as a procedural end-point and intraoperative intraaortic balloon pump insertion. However, after adjusting for significant baseline and intraoperative covariates, procedure duration still was associated with increased hospital mortality. Procedure duration had no impact on VT recurrence and survival at 6 months.
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http://dx.doi.org/10.1016/j.hrthm.2014.10.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4282181PMC
January 2015

Do preoperative β-blockers improve postoperative outcomes in patients undergoing cardiac surgery? Challenging societal guidelines.

Am Surg 2014 Oct;80(10):1018-21

UCLA Division of Cardiac Surgery, Los Angeles, California, USA.

Preoperative β-blockers (BBs) are widely administered to reduce morbidity and mortality among surgical patients. In fact, the Society of Thoracic Surgeons uses the administration of preoperative BBs as a quality metric. Recent reports, however, have questioned the benefit and safety of preoperative BB administration. The aim of our study was to investigate whether preoperative BBs lead to improved surgical outcomes in patients undergoing cardiac surgery. A review of our prospectively maintained institutional database was done to identify adults undergoing cardiac operations at our institution from 2008 to 2013. Survival to discharge was the primary outcome with several additional secondary measures of morbidity included. A total of 2120 patients were included in the analysis and a multivariate logistic regression model was developed to adjust for differences between patient groups. After adjustment, BB administration was associated with lower odds of both prolonged ventilation (odds ratio [OR], 0.73; P = 0.032) and prolonged length of stay (OR, 0.79; P = 0.044). BB use was not associated with significant differences in other outcomes such as mortality or postoperative atrial fibrillation. Our study found that preoperative BBs may not be associated with sufficiently improved outcomes to justify their use as a quality metric in this population. Thus, prospective studies are warranted.
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October 2014

Non-invasive brain stimulation in neurorehabilitation: local and distant effects for motor recovery.

Front Hum Neurosci 2014 27;8:378. Epub 2014 Jun 27.

Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, NIH Bethesda, MD, USA ; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of Health Sciences Bethesda, MD, USA.

Non-invasive brain stimulation (NIBS) may enhance motor recovery after neurological injury through the causal induction of plasticity processes. Neurological injury, such as stroke, often results in serious long-term physical disabilities, and despite intensive therapy, a large majority of brain injury survivors fail to regain full motor function. Emerging research suggests that NIBS techniques, such as transcranial magnetic (TMS) and direct current (tDCS) stimulation, in association with customarily used neurorehabilitative treatments, may enhance motor recovery. This paper provides a general review on TMS and tDCS paradigms, the mechanisms by which they operate and the stimulation techniques used in neurorehabilitation, specifically stroke. TMS and tDCS influence regional neural activity underlying the stimulation location and also distant interconnected network activity throughout the brain. We discuss recent studies that document NIBS effects on global brain activity measured with various neuroimaging techniques, which help to characterize better strategies for more accurate NIBS stimulation. These rapidly growing areas of inquiry may hold potential for improving the effectiveness of NIBS-based interventions for clinical rehabilitation.
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http://dx.doi.org/10.3389/fnhum.2014.00378DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4072967PMC
July 2014

Biophysical parameters during radiofrequency catheter ablation of scar-mediated ventricular tachycardia: epicardial and endocardial applications via manual and magnetic navigation.

J Cardiovasc Electrophysiol 2014 Nov 24;25(11):1165-73. Epub 2014 Jul 24.

UCLA Cardiac Arrhythmia Center, UCLA Health System, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.

Background: There is a paucity of data on biophysical parameters during radiofrequency ablation of scar-mediated ventricular tachycardia (VT).

Methods And Results: Data were collected from consecutive patients undergoing VT ablation with open-irrigation. Complete data were available for 372 lesions in 21 patients. The frequency of biophysical parameter changes were: >10Ω reduction (80%), bipolar EGM reduction (69%), while loss of capture was uncommon (32%). Unipolar injury current was seen in 72% of radiofrequency applications. Both EGM reduction and impedance drop were seen in 57% and a change in all 3 parameters was seen in only 20% of lesions. Late potentials were eliminated in 33%, reduced/modified in 56%, and remained after ablation in 11%. Epicardial lesions exhibited an impedance drop (90% vs. 76%, P = 0.002) and loss of capture (46% vs. 27%, P < 0.001) more frequently than endocardial lesions. Lesions delivered manually exhibited a >10Ω impedance drop (83% vs. 71%, P = 0.02) and an EGM reduction (71% vs. 40%, P < 0.001) more frequently than lesions applied using magnetic navigation, although loss of capture, elimination of LPs, and a change in all 3 parameters were similarly observed.

Conclusions: VT ablation is inefficient as the majority of radiofrequency lesions do not achieve more than one targeted biophysical parameter. Only one-third of RF applications targeted at LPs result in complete elimination. Epicardial ablation within scar may be more effective than endocardial lesions, and lesions applied manually may be more effective than lesions applied using magnetic navigation. New technologies directed at identifying and optimizing ablation effectiveness in scar are clinically warranted.
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http://dx.doi.org/10.1111/jce.12477DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4282185PMC
November 2014

Comparative safety of periablation anticoagulation strategies for atrial fibrillation: data from a large multicenter study.

Pacing Clin Electrophysiol 2014 Jun 4;37(6):665-73. Epub 2014 May 4.

Arrhythmia Institute, Valley Health System, New York, New York and Ridgewood, New Jersey.

Background: There are a variety of periprocedural anticoagulation strategies for atrial fibrillation (AF) ablation, including the use of dabigatran. It is unclear which strategy is superior.

Objective: To compare the safety and efficacy of anticoagulation with uninterrupted warfarin, dabigatran, and warfarin with heparin bridging in patients undergoing ablation of AF at four experienced centers.

Methods And Results: In this retrospective analysis, 882 patients (mean age: 61 ± 11 years) underwent ablation of AF using uninterrupted warfarin (n = 276), dabigatran (n = 374), or warfarin with heparin bridging (n = 232) for periprocedural anticoagulation. The rate of total complications was 23/276 (8.3%) in the uninterrupted warfarin group, 30/374 (8.0%) in the dabigatran group, and 29/232 (12.5%) in the bridged group (P = 0.15). Major complications were more frequent in the uninterrupted warfarin group 12/276 (4.3%) compared with 3/374 (0.8%) in dabigatran and 6/232 (2.6%) in the bridged group (P = 0.01). The most common major complication was the need for transfusion or occurrence of major bleeding. Minor complications did not differ among the three groups. On multivariate analysis, female gender (odds ratio [OR] 1.93, confidence interval [CI] 1.16-3.19, P = 0.011), bridging heparin (OR 2.13, CI 1.100-3.941, P = 0.016), use of triple antithrombotic therapy (OR 1.77, CI 1.05-2.98, P = 0.033), and prior myocardial infarction (OR 2.40, CI 1.01-5.67, P = 0.046) independently predicted total complications.

Conclusions: When comparing the use of uninterrupted warfarin, dabigatran, and warfarin with heparin bridging in patients undergoing catheter ablation of AF, dabigatran was not associated with increased risk, major complications were more common in the uninterrupted warfarin group, and after adjustment, warfarin with bridging increased total complications.
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http://dx.doi.org/10.1111/pace.12401DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4253027PMC
June 2014

Can cortical stimulation of inferior frontal cortex enhance proactive control?

J Neurosci 2014 Apr;34(18):6125-7

Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, United Kingdom, Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom, Human Cortical Physiology and Neurorehabilitation Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20814, and Center for Neuroscience and Regenerative Medicine, Uniformed Services University of Health Sciences, Bethesda, Maryland 20814.

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http://dx.doi.org/10.1523/JNEUROSCI.0590-14.2014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4004802PMC
April 2014

Analysis of emergency department visits for palpitations (from the National Hospital Ambulatory Medical Care Survey).

Am J Cardiol 2014 May 1;113(10):1685-90. Epub 2014 Mar 1.

Department of Emergency Medicine, Oregon Health and Science University, Portland, Oregon.

Palpitations is a common complaint in patients who visit the emergency department (ED), with causes ranging from benign to life threatening. We analyzed the ED component of the National Hospital Ambulatory Medical Care Survey for 2001 through 2010 for visits with a chief complaint of palpitations and calculated nationally representative weighted estimates for prevalence, demographic characteristics, and admission rates. ED and hospital discharge diagnoses were tabulated and categorized, and recursive partitioning was used to identify factors associated with admission. An estimated 684,000 visits had a primary reason for visit of "palpitations" representing a national prevalence of 5.8 per 1,000 ED visits (0.58%, 95% confidence interval 0.52 to 0.64). Women and non-Hispanic whites were responsible for most visits. A cardiac diagnosis made up 34% of all ED diagnoses. The overall admission rate was 24.6% (95% confidence interval 21.2 to 28.1), with higher rates seen in the Midwest and Northeast compared with the West. Survey-weighted recursive partitioning revealed several factors associated with admission including age >50 years, male gender, cardiac ED diagnosis, tachycardia, hypertension, and Medicare insurance. In conclusion, palpitations are responsible for a significant minority of ED visits and are associated with a cardiac diagnosis roughly 1/3 of the time. This was associated with a relatively high admission rate, although significant regional variation in these rates exists.
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http://dx.doi.org/10.1016/j.amjcard.2014.02.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4011931PMC
May 2014

CHADS2 score predicts atrial fibrillation following cardiac surgery.

J Surg Res 2014 Aug 15;190(2):407-12. Epub 2014 Feb 15.

Division of Cardiothoracic Surgery, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California. Electronic address:

Background: Atrial fibrillation (AF) following cardiac surgery portends higher morbidity and increased health expenditure. Although many anatomic and patient risk factors have been identified, a simple clinical scoring system to identify high-risk patients is lacking. The CHADS2 score is widely used to predict the risk of stroke in patients with AF. We assessed the utility of this scoring algorithm in predicting the development of de novo postoperative atrial fibrillation (POAF) in cardiac surgery patients.

Material And Methods: A total of 2120 patients from 2008 to 2013 were identified for inclusion in our analysis. CHADS2 scores were calculated, and patients grouped into low- (0), intermediate- (1) and high-risk (≥2) categories. A multivariate regression model was developed to account for known risk factors of AF.

Results: Of the 2120 patients, 344 (16.2%) patients developed de novo POAF during their primary hospitalization. Mean CHADS2 scores for POAF patients and no POAF patients were 2.1 ± 1.2 and 1.7 ± 1.3 (P < 0.0001), respectively. CHADS2 score was a significant predictor of AF on multivariate regression analysis (adjusted odds ratio, 1.26; 95% confidence interval, 1.14-1.40). As CHADS2 score increased from 0 to 6, the probability of POAF increased from 11.1% to 32.7% (P < 0.0001). Compared with the low-risk group, the intermediate-risk and high-risk groups had a 1.73- and 2.58-fold increase in odds of developing POAF, respectively (P < 0.02 and P < 0.0001).

Conclusions: CHADS2 score is a powerful and convenient predictor of developing POAF. We recommend its utilization in identifying high-risk patients that may benefit from pharmacologic prophylaxis.
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http://dx.doi.org/10.1016/j.jss.2014.02.007DOI Listing
August 2014

Marshaling the autonomic nervous system for treatment of atrial fibrillation.

J Am Coll Cardiol 2014 May 19;63(18):1902-3. Epub 2014 Feb 19.

UCLA Cardiac Arrhythmia Center, UCLA, Los Angeles, California; David Geffen School of Medicine, UCLA, Los Angeles, California; Molecular, Cellular and Integrative Physiology Program, UCLA, Los Angeles, California; Neurocardiology Program, Center for Neurobiology of Stress, UCLA, Los Angeles, California. Electronic address:

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http://dx.doi.org/10.1016/j.jacc.2014.01.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4219829PMC
May 2014