bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrical Homogenization of Ventricular Scar by Application of Collagenase
Authors: Yagishita Daigo , Ajijola Olujimi A. , Vaseghi Marmar , Nsair Ali , Zhou Wei , Yamakawa Kentaro , Tung Roderick , Mahajan Aman , Shivkumar Kalyanam 
Published: July 2013

Background—
Radiofrequency ablation for ventricular tachycardia is an established therapy. Use of chemical agents for scar homogenization represents an alternative approach. The purpose of this study was to characterize the efficacy of collagenase (CLG) application on epicardial ventricular scar homogenization.

Methods and Results—

Myocardial infarcts were created in Yorkshire pigs (n=6) by intracoronary microsphere injection. After 46.6±4.3 days, CLG type 2, type 4, and purified CLG were applied in vitro (n=1) to myocardial tissue blocks containing normal myocardium, border zone, and dense scar. Histopathologic studies were performed to identify the optimal CLG subtype. In vivo high-density electroanatomic mapping of the epicardium was also performed, and border zone and dense scar surface area and late potentials were quantified before and after CLG-4 application (n=5). Of the CLG subtypes tested in vitro, CLG-4 provided the best scar modification and least damage to normal myocardium. During in vivo testing, CLG-4 application decreased border zone area (21.3±14.3 to 17.1±11.1 mm
2
,
P
=0.043) and increased dense scar area (9.1±10.3 to 22.0±20.6 mm
2
,
P
=0.043). The total scar area before and after CLG application was 30.4±23.4 and 39.2±29.5 mm
2
, respectively (
P
=0.08). Late potentials were reduced by CLG-4 application (28.8±21.8 to 13.8±13.1,
P
=0.043). During CLG-4 application (50.0±15.5 minutes), systolic blood pressure and heart rate were not significantly changed (68.0±7.7 versus 61.8±5.3 mmHg,
P
=0.08; 77.4±7.3 versus 78.8±6.0 beats per minute,
P
=0.50, respectively).

Conclusions—
Ventricular epicardial scar homogenization by CLG-4 application is feasible and effective. This represents the first report on bioenzymatic ablation of arrhythmogenic tissue as an alternative strategy for lesion formation.
The Role of Implantable Cardioverter-Defibrillators in Patients With Continuous Flow Left Ventricular Assist Devices
Authors: Enriquez Alan D. , Calenda Brandon , Miller Marc A. , Anyanwu Anelechi C. , Pinney Sean P. 
Published: July 2013

Background—
The prognosis for patients experiencing ventricular arrhythmias (VAs) while on continuous flow left ventricular assist device (LVAD) support has not been well elucidated. Accordingly, the role of implantable cardioverter-defibrillators (ICDs) in this patient population remains undefined.

Methods and Results—

Records of 106 consecutive patients undergoing implantation of the HeartMate II LVAD at a single center were reviewed. For patients surviving >30 days postimplant (98 patients), the impact of VAs and ICDs on survival was analyzed. Mean age was 56.6±11.4 years, 82.1% were male, 42.5% had an ischemic cardiomyopathy, 87.7% were bridge to transplantation, and median length of support was 217 days. Twenty-one (19.8%) patients died, 60 (56.6%) survived to transplantation, and 25 patients (23.6%) reached the end of study, had the LVAD explanted, or were lost to follow-up. Post-LVAD VAs occurred in 37 patients (34.9%) but were not associated with increased mortality (hazard ratio, 0.58 [0.18–1.90]). Sixty-two (63.3%) patients had an active ICD, and 36 (36.7%) patients had no ICD or an inactivated ICD post-LVAD. Patients with an ICD were more likely to be INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) level 3 or 4 at the time of implant (54.8% versus 33.3%;
P
=0.04). An appropriate shock was delivered in 27.3% of patients, but the presence of an active ICD was not associated with improved survival (hazard ratio, 1.12 [0.37–3.35]).

Conclusions—
VAs are common in patients with continuous flow LVADs. Although some episodes may be clinically significant, VAs are not associated with a worse prognosis, and concomitant ICDs in these patients may not reduce mortality.
Locations of High Contact Force During Left Atrial Mapping in Atrial Fibrillation Patients
Authors: Nakagawa Hiroshi , Kautzner Josef , Natale Andrea , Peichl Petr , Cihak Robert , Wichterle Dan , Ikeda Atsushi , Santangeli Pasquale , Di Biase Luigi , Jackman Warren M. 
Published: July 2013

Background—
During radiofrequency ablation, high electrode-tissue contact force (CF) is associated with increased risk of steam pop and perforation. The purpose of this study, in patients undergoing ablation of paroxysmal atrial fibrillation, was to: (1) identify factors producing high CF during left atrial (LA) and pulmonary vein mapping; (2) determine the ability of atrial potential amplitude and impedance to predict CF; and (3) explore the feasibility of controlling radiofrequency power based on CF.

Methods and Results—
A high-density map of LA/pulmonary veins (median 328 sites) was obtained in 18 patients undergoing atrial fibrillation ablation using a 7.5-Fr irrigated mapping/ablation catheter to measure CF. Average CF was displayed on the 3D map. For 5682 mapped sites, CF ranged 1–144 g (median 8.2 g). High CF (≥35 g) was observed at only 118/5682 (2%) sites, clustering in 6 LA regions. The most common high CF site (48/113 sites in 17/18 patients) was located at the anterior/rightward LA roof, directly beneath the ascending aorta (confirmed by merging the CT image and map). Poor relationship between CF and either unipolar amplitude, bipolar amplitude, or impedance was observed. During ablation, radiofrequency power was modulated based on CF. All pulmonary veins were isolated without steam pop, impedance rise, or pericardial effusion.

Conclusions—
High CF often occurs at anterior/rightward roof, where the ascending aorta provides resistance to the LA. Atrial potential amplitude and impedance are poor predictors of CF. Controlling radiofrequency power based on CF seems to prevent steam pop and impedance rise without loss of lesion effectiveness.
Cardiorespiratory Fitness, Body Mass Index, and Heart Failure Mortality in Men
Authors: Farrell Stephen W. , Finley Carrie E. , Radford Nina B. , Haskell William L. 
Published: July 2013

Background—
We evaluated the individual and joint associations among cardiorespiratory fitness (CRF), body mass index, and heart failure (HF) mortality, as well as the additive effect of an increasing number of cardiovascular risk factors on HF mortality in fit versus unfit men.

Methods and Results—

A total of 44 674 men without a history of cardiovascular disease underwent a baseline examination between 1971 and 2010. Measures included body mass index and CRF quantified as duration of maximal treadmill exercise testing. Participants were divided into age-specific low, moderate, and high CRF categories. Hazard ratios were computed with Cox regression analysis. During a mean follow-up of 19.8±10.4 years, 153 HF deaths occurred. Adjusted hazard ratios across high, moderate, and low CRF categories were 1.0, 1.63, and 3.97, respectively, whereas those of normal, overweight, and obese body mass index categories were 1.0, 1.56, and 3.71, respectively (
P
for trend <0.0001 for each). When grouped into categories of fit and unfit (upper 80% and lower 20% of CRF distribution, respectively), hazard ratios were significantly lower in fit compared with unfit men in normal and overweight body mass index strata (
P
<0.002) but not in obese men. Within men matched for the same number of HF risk factors, fit men had significantly lower HF mortality than unfit men (
P
≤0.02).

Conclusions—
Higher baseline CRF is associated with lower HF mortality risk in men, regardless of the number of HF risk factors present. Men should be counseled on physical activity with the goal of achieving at least a moderate level of CRF, thereby presumably decreasing their risk of HF mortality.
The COP9 Signalosome Is Required for Autophagy, Proteasome-Mediated Proteolysis, and Cardiomyocyte Survival in Adult Mice
Authors: Su Huabo , Li Jie , Osinska Hanna , Li Faqian , Robbins Jeffrey , Liu Jinbao , Wei Ning , Wang Xuejun 
Published: July 2013

Background—
The COP9 signalosome (CSN) is an evolutionarily conserved protein complex composed of 8 unique protein subunits (CSN1 through CSN8). We have recently discovered in perinatal mouse hearts that CSN regulates not only proteasome-mediated proteolysis but also macroautophagy. However, the physiological significance of CSN in a post-mitotic organ of adult vertebrates has not been determined. We sought to study the physiological role of CSN8/CSN in adult mouse hearts.

Methods and Results—

Csn8

was conditionally ablated in the cardiomyocytes of adult mice (CSN8
CKO
) using a temporally controlled Cre-LoxP system. Loss of CSN8 accumulated the neddylated forms of cullins and noncullin proteins, increased ubiquitinated proteins, and stabilized a surrogate substrate of the proteasome in the heart. Autophagic flux was significantly decreased, whereas autophagosomes were markedly increased in CSN8
CKO
hearts, indicative of impaired autophagosome removal. Furthermore, we observed increased oxidized proteins, massive necrotic cardiomyocytes, and morphological and functional changes characteristic of dilated cardiomyopathy in CSN8
CKO
mice.

Conclusions—
CSN deneddylates substrates more than cullins and is indispensable to cardiomyocyte survival in not only perinatal hearts but also adult hearts. CSN8/CSN regulates both proteasome-mediated proteolysis and the autophagic-lysosomal pathway, critical to the removal of oxidized proteins in the heart.
Cardiovascular Magnetic Resonance Characteristics in Children With Hypertrophic Cardiomyopathy
Authors: Chaowu Yan , Shihua Zhao , Jian Ling , Li Li , Wei Fang 
Published: July 2013

Background—
Cardiovascular magnetic resonance has provided important information on the diagnosis and risk stratification of hypertrophic cardiomyopathy (HCM) in adults; however, comparable data are absent for HCM in children. The study was performed to evaluate cardiovascular magnetic resonance characteristics in children with idiopathic HCM.

Methods and Results—

Cardiovascular magnetic resonance was performed in 71 consecutive children with idiopathic HCM (age, 12.8±4.1 years; 46 boys and 25 girls). The left ventricular (LV) parameters indexed by body surface area were calculated and compared with those in 71 healthy children (age, 13.1±3.3 years; 51 boys and 20 girls). Among those with HCM, concentric LV hypertrophy occurred in 9 patients (12.7%): in 2 children, it progressed into end-stage phase. The prevalence of late gadolinium enhancement (LGE) was 73%, and the extent of LGE was 10.4±8.3% of LV mass. Children with HCM with LGE had greater LV mass indexed (112.7±57.9 versus 70.3±37.4 g/m
2
;
P
=0.025) but had no significant difference in maximal LV wall thickness indexed (19.4±6.3 versus 18.1±7.9 mm/m
2
;
P
=0.513). In addition, the hazard ratio of adverse events for the extent of LGE was 1.1 (
P
=0.004). The follow-up (2.4±1.6 years) demonstrated that LGE was associated with adverse events in children with HCM (log-rank;
P
=0.029).

Conclusions—
The prevalence and extent of LGE in children with HCM approximate to those in adults with HCM. Furthermore, children with HCM with LGE tend to have adverse events, and larger researches with longer follow-up are required.
Assessment of Mitral Valve Adaptation With Gated Cardiac Computed Tomography
Authors: Beaudoin Jonathan , Thai Wai-Ee , Wai Bryan , Handschumacher Mark D. , Levine Robert A. , Truong Quynh A. 
Published: July 2013

Background—
Mitral valve (MV) enlargement is a compensatory mechanism capable of preventing functional mitral regurgitation (FMR) in dilated ventricles. Total leaflet area and its relation with closure area measured by 3-dimensional (3D) echocardiography have been related to FMR. Whether these parameters can be assessed with other imaging modalities is not known. Our objectives are to compare cardiac computed tomography (CT)–based measurements of MV leaflets with 3D echocardiography and determine the relationship of these metrics to the presence of FMR.

Methods and Results—

We used 2 cohorts of patients who had cardiac CT to measure MV total leaflet, closure, and annulus areas. In cohort 1 (26 patients), we validated these CT metrics to 3D echocardiography. In cohort 2 (66 patients), we assessed the relation of MV size with the presence of FMR in 3 populations: heart failure with FMR, heart failure without FMR, and normal controls. Cardiac CT and 3D echocardiography produced similar results for total leaflet (
R
2
=0.97), closure (
R
2
=0.89), and annulus areas (
R
2
=0.84). MV size was the largest in heart failure without FMR compared with controls and patients with FMR (9.1±1.7 versus 7.5±1.0 versus 8.1±0.9 cm
2
/m
2
;
P
<0.01). Patients with FMR had reduced ratios of total leaflet to closure areas and total leaflet to annulus areas when compared with patients without FMR (
P
<0.01).

Conclusions—
MV size measured by CT is comparable with 3D echocardiography. MV enlargement in cardiomyopathy suggests leaflet adaptation. Patients with FMR have inadequate adaptation as reflected by decreased ratios of leaflet area and areas determined by ventricle size (annulus and closure areas). These measurements provide additional insight into the mechanism of FMR.
Lessons From the Tc-99m Shortage
Authors: Small Gary R. , Ruddy Terrence D. , Simion Oana , Alam Mohammed , Fuller Lyanne , Chen Li , Beanlands Rob S. , Chow Benjamin J.W. 
Published: July 2013

Background—
In 2009, the Chalk River nuclear reactor closed for repairs that led to a critical shortage of technetium-99m (Tc-99m). Several centers used thallium-201 (Tl-201) as an alternative radiotracer for myocardial perfusion imaging. Because Tl-201 is considered by many as a suboptimal radiotracer, we sought to understand the impact of using Tl-201 (during the Tc-99m shortage) on downstream resource utilization.

Methods and Results—

We performed a retrospective study at the Ottawa Heart Institute of 7402 patients (60% men; mean age, 62.6±11.8 years), patients were referred for myocardial perfusion imaging between May 2008 and January 2011 (PRE_Tc-99m [2938 patients]), during (DURING_Tl-201 [2959 patients]), and after (POST_Tc-99m [1505 patients]) the Tc-99m shortage. Patients were followed for 6 months after their index myocardial perfusion imaging to determine subsequent rates of cardiac catheterization or noninvasive imaging. More downstream testing was seen in the Tl-201 cohort (639 [21.4%] patients) than the Tc-99m cohort (537 [12.1%] patients;
P
<0.001). After adjustment using propensity scores, differences in downstream referral rates were maintained. The downstream investigations resulted in an estimated increase in per-patient costs ($165.22; 95% confidence interval, 153.00–177.42) in the DURING_Tl-201 cohort compared with the Tc-99m cohort ($90.97; 95% confidence interval, 83.42–98.90;
P
<0.001). As well, the mean effective radiation dose per-patient was higher in DURING_Tl-201 (23.57 mSv; 95% confidence interval, 23.16–23.96) than in Tc-99m (12.92 mSv; 95% confidence interval, 12.55–13.40;
P
<0.001).

Conclusions—
In this single-center study, the use of Tl-201 during the Tc-99m shortage was associated with an increase in downstream testing, cost, and patient radiation exposure, but these findings may not be generalizable to other centers. Although Tl-201 provided a short-term solution to the unexpected Tc-99m shortage, long-term cost-effective solutions should be areas of future study.
Expansion of Invasive Cardiac Services in the United States
Authors: Horwitz Jill R. , Nichols Austin , Nallamothu Brahmajee K. , Sasson Comilla , Iwashyna Theodore J. 
Published: July 2013

Background—
The number of hospitals offering invasive cardiac services (diagnostic angiography, percutaneous coronary intervention, and coronary artery bypass grafting) has expanded, yet national patterns of service diffusion and their effect on geographic access to care are unknown.

Methods and Results—
This is a retrospective cohort study of all hospitals in fee-for-service Medicare, 1996 to 2008. Logistic regression identified the relationship between cardiac service adoption and the proportion of neighboring hospitals within 40 miles already offering the service. From 1996 to 2008, 397 hospitals began offering diagnostic angiography, 387 percutaneous coronary intervention, and 298 coronary artery bypass grafting (increasing the proportion with services by 3%, 11%, and 4%, respectively). This capacity increase led to little new geographic access to care; the population increase in geographic access to diagnostic angiography was 1 percentage point; percutaneous coronary intervention 5 percentage points, and coronary artery bypass grafting 4 percentage points. Controlling for hospital and market characteristics, a 10 percentage point increase in the proportion of nearby hospitals already offering the service increased the odds by 10% that a hospital would add diagnostic angiography (odds ratio, 1.102; 95% confidence interval, 1.018–1.193), increased the odds by 79% that it would add percutaneous coronary intervention (odds ratio, 1.794; 95% confidence interval, 1.288–2.498), and had no significant effect on adding coronary artery bypass grafting (odds ratio, 0.929; 95% confidence interval, 0.608–1.420).

Conclusions—
Hospitals are most likely to introduce new invasive cardiac services when neighboring hospitals already offer such services. Increases in the number of hospitals offering invasive cardiac services have not led to corresponding increases in geographic access.
Intercultural Encounters in Collective Narratives: The Transition of “The Shining Robe” from North Africa to Ashkenaz via Provence
Authors: Kushelevsky Rella 
Published: July 2013

Abstract
Collective narratives that have been received by a society as part of its culture are based on and respond to prevalent norms and values. Whether they conform to or criticize existing conventions, collective narratives are created within a cultural historical context that should be reconstructed as a point of departure for interpretation. In this article I focus on “The Shining Robe”, a story incorporated in Hibbur Yafeh MeHa’yeshua authored by Rabbi Nissim Gaon of Kairouan (first half of the 11th century). The choice of this story is intriguing due to its foreign nature and its departure from the gender norms that prevailed in Ashkenaz, compared to the gender norms that were prevalent in the Jewish-Muslim context. I argue that the response that this story evoked in Ashkenaz, whether explicit or implicit, made it necessary to cross cultural bridges between Kairouan where it was created and the cultural context where it was received. I refer to the Judeo-Arabic version of Hibbur Yafeh in comparison to its translations-adaptations in Ashkenaz dated to the 13th-16th centuries. These adapted versions are briefly compared also to its parallel in Provence, translated from the Judeo-Arabic.
Early Muslim Medicine and the Indian Context: A Reinterpretation
Authors: Shefer-Mossensohn M. , Hershkovitz K. Abou 
Published: July 2013

Abstract
The past few decades have witnessed a remarkable shift in the way scholars study the field of sciences in Muslim societies. Up to the 1980s, research focused on Muslim scientists’ role as transmitters of science to the West, and as contributors to Western science. The Muslim world was commonly viewed as a link between ancient Greece and Latin Christendom, its scholars serving as translators of Greek treatises, and as preservers of Greek knowledge. Recently, the theme of Indian-Muslim cultural-scientific relations has attracted growing attention. Following this trend, we maintain that the eighth and ninth centuries reveal an interaction between Indian and Muslim medicine and physicians. Building on the past work of scholars such as Michael W. Dols and more recently Kevin van Bladel, we reinterpret medieval Arabic sources to reveal that the interest in Asian science was not a brief and untypical phenomenon that lacked long-lasting implications. By rereading Arabic chronicles and biographical dictionaries, we will portray how a rather brief contact between ʿAbbāsid Iraq and India proved to yield enduring influences. We will focus on two aspects of Muslim medical practice for demonstrating the Indian connection: the presence of Indian physicians in Baghdād in and around the ʿAbbāsid court, and the emergence of early Muslim hospitals.
Spectacle, Community and Holy War in Fourteenth-Century Cyprus
Authors: Devaney Thomas 
Published: July 2013

Abstract
This article examines how temporal and ecclesiastic authorities on Lusignan Cyprus used rhetoric and performance to mobilize support for the Alexandria Crusade. While King Peter I appealed to the chivalric ideals of his vassals in order to overcome their reluctance to endanger the kingdom’s economic and military security, papal legate Peter of Thomas led interfaith processions that presented Cyprus’s population as united in its Christian devotion despite long-standing tensions between the Latin and Greek communities. This presentation of a shared Cypriot identity reflected nascent moves away from the physical and social segregation of confessional groups. It also clarifies the role played by perceptions of a constant threat of Mamlūk invasion in this process of acculturation. Such concerns and responses were not unique to Cyprus. By considering late-medieval Cyprus as a frontier society, we can gain insight into the complex politics of holy war in other composite medieval communities.
“Halting Between Two Opinions”: Conversion and Apostasy in Early Islam
Authors: Simonsohn Uriel 
Published: July 2013

Abstract
The phenomenon of individuals converting to Islam and later returning to their former religions is well attested in both narrative and documentary records from the early Islamic period. Such shifts in religious commitments posed social and legal problems for the communities to which their former members sought reentry. Specifically, legal authorities were faced with the challenge of assessing the trustworthiness of returning apostates, whether their return was wholehearted and sincere or, rather, opportunistic and deceitful. The present discussion offers the historical context and a comparative analysis of some of the legal mechanisms by which the Jewish geʾonim of Babylonia and Eastern Christian church leaders attempted to overcome this challenge.