Italian heart journal : official journal of the Italian Federation of Cardiology最新文献

{"title":"Pulmonary arterial hypertension: therapeutic algorithm.","authors":"Nazzareno Galiè,&nbsp;Angelo Branzi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The numerous controlled clinical trials performed recently in pulmonary arterial hypertension (PAH) can allow us to abandon a clinical-based treatment strategy and adopt an evidence-based therapy. The treatment algorithm is restricted to patients in NYHA class III or IV. The different treatments have been evaluated mainly in sporadic, idiopathic PAH and in PAH associated with scleroderma or to anorexigen use. Extrapolation of these recommendations to other PAH subgroups should be done with caution. High doses of calcium channel blockers are indicated only in the minority of patients who are responders to acute vasoreactivity testing. Patients in NYHA class III should be considered candidates for treatment with either an endothelin receptor antagonist, a prostanoid or a type 5 phosphodiesterase inhibitor. Continuous intravenous administration of epoprostenol is proposed as rescue treatment in NYHA class IV patients. Combination therapy can be attempted in selected cases. Balloon atrial septostomy and/or lung transplantation are indicated for refractory patients or when medical treatments are unavailable.</p>","PeriodicalId":80289,"journal":{"name":"Italian heart journal : official journal of the Italian Federation of Cardiology","volume":"6 10","pages":"856-60"},"PeriodicalIF":0.0,"publicationDate":"2005-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25673934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From acute pulmonary embolism to chronic thromboembolic pulmonary hypertension.","authors":"Vittorio Pengo,&nbsp;Paolo Prandoni","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Chronic thromboembolic pulmonary hypertension (CTEPH), a disease associated with considerable morbidity and mortality, is the consequence of unresolved thromboembolic occlusion in pulmonary vasculature. CTEPH was considered a rare disease occurring in 0.1-0.5% of patients with pulmonary emboli who survive. Recently, a much higher incidence was reported and some risk factors such as a previous pulmonary embolism (PE), an idiopathic form of PE and the severity of perfusion defect at the time of diagnosis have been identified. Exertional dyspnea is the main symptom at the beginning of the disease while later on patients may suffer from syncope related to low cardiac output or hemoptysis as a consequence of high pulmonary artery pressure. In suspected patients, a confirmation of pulmonary arterial hypertension should be ascertained at transthoracic echocardiography. Then the obstructive nature of the disease may be revealed by ventilation-perfusion lung scan but is better described at pulmonary angiography. Computed tomography scan may be useful to rule out confounding disorders. To prevent recurrences, long-term oral anticoagulants to maintain an INR between 2.5 and 3.5 (target 3.0) are indicated. Treatment of severe CTEPH is essentially surgical (thromboendarterectomy). This procedure may be difficult when distal branches of pulmonary vascular tree are involved. In selected cases, alternative therapies may be the arterial pulmonary vessel angioplasty and lung transplantation.</p>","PeriodicalId":80289,"journal":{"name":"Italian heart journal : official journal of the Italian Federation of Cardiology","volume":"6 10","pages":"830-3"},"PeriodicalIF":0.0,"publicationDate":"2005-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25674032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pulmonary embolism: role of echocardiography and of biological markers.","authors":"Adam Torbicki,&nbsp;Piotr Pruszczyk,&nbsp;Marcin Kurzyna","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Echocardiography and biomarkers: what should be their place in the algorithms designed for pulmonary embolism (PE)? Our opinions on that continue to evolve. This manuscript attempts a snapshot reflecting the position of cardiac imaging and cardiac biomarkers in suspected and confirmed PE. Comparing the prognostic performance of brain natriuretic peptide (BNP) and troponins, it seems that with thresholds set appropriately high, troponins could be more helpful in the identification of patients with adverse prognosis while low BNP levels are reliable markers of good prognosis. Because of the relatively short plasma half-life, BNP as well as NT-proBNP could be repeated to monitor evolution of the hemodynamic status of the patient and the results of implemented treatment. The role of echocardiography outside massive PE seems to be decreasing, although if considered together with information provided on potential alternative or additional cardiovascular diseases as well as intracardiac or intravascular thrombi, its place in a tentative management algorithm in PE seems still secured.</p>","PeriodicalId":80289,"journal":{"name":"Italian heart journal : official journal of the Italian Federation of Cardiology","volume":"6 10","pages":"805-10"},"PeriodicalIF":0.0,"publicationDate":"2005-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25674028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pulmonary embolism: lung scan and computed tomography.","authors":"Carlo Marini,&nbsp;Antonio Palla,&nbsp;Carlo Giuntini","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The diagnosis of pulmonary embolism may be confounded by a clinical presentation that is often subtle or atypical. Therefore pulmonary angiography, although invasive, has been widely used to prove pulmonary embolism. The aim of this review is to discuss the value of non-invasive techniques, such as lung scan and chest computed tomography scan, in the diagnosis of pulmonary embolism. Ventilation-perfusion scan has demonstrated a very high specificity (97%) but a quite low sensitivity (41%) in the diagnosis of pulmonary embolism, while perfusion lung scan not associated with ventilation scan has shown a specificity of 92% and a considerably high sensitivity (87%). The chest computed tomography scan has not yet shown a definite degree of specificity and sensitivity in the diagnosis of pulmonary embolism, although we suppose that this technique will become widely used. However, we emphasize that the diagnosis of pulmonary embolism is not a mere technical problem.</p>","PeriodicalId":80289,"journal":{"name":"Italian heart journal : official journal of the Italian Federation of Cardiology","volume":"6 10","pages":"811-7"},"PeriodicalIF":0.0,"publicationDate":"2005-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25674029","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ventricular capture management in pediatric pacing: efficacy and safety.","authors":"Massimo S Silvetti,&nbsp;Antonella De Santis,&nbsp;Giorgia Grutter,&nbsp;Vincenzo Di Ciommo,&nbsp;Fabrizio Drago","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Background: </strong>The Ventricular Capture Management (VCM) of Medtronic Kappa 700 series pacemakers (PM) performs automatic threshold detection and optimization of pacing output that may enhance generator longevity. We evaluated efficacy and safety of this algorithm in children.</p><p><strong>Methods: </strong>The study was prospective, non-randomized, involving 50 consecutive patients (mean age 5.6 +/- 6.6 years, median 4 years), enrolled at first PM implant. VCM was active from the implant, with nominal values of safety margin, minimum adapted pulse amplitude and width. Leads were endocardial and epicardial, all unipolar. Thresholds and pacing outputs were registered with telemetric PM interrogation. Endocardial and epicardial thresholds and outputs were also compared. Follow-up duration was 27 +/- 13 months (range 6-49 months).</p><p><strong>Results: </strong>A significant reduction in pulse amplitude was evident since the sixth month. Thresholds and outputs were lower in endocardial than in epicardial pacing. A false negative capture detection occurred during the \"acute phase\" in 3 patients (6.0%), with incorrect automatic output increase to 5 V/1 ms. After this phase, the problem was still detected in 2 patients (4.0%). VCM correctly identified threshold increases in 2 patients (1%). No pacing defect was documented. VCM was not performed in 4 infants (8.0%) for pacing rate > or = 100 b/min.</p><p><strong>Conclusions: </strong>VCM function is safe and effective in reducing pacing output in pediatric patients; this may increase PM longevity. Epicardial pacing shows higher thresholds and outputs than endocardial pacing.</p>","PeriodicalId":80289,"journal":{"name":"Italian heart journal : official journal of the Italian Federation of Cardiology","volume":"6 9","pages":"751-6"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25626750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predictive parameters of left ventricular reverse remodeling in response to cardiac resynchronization therapy in patients with severe congestive heart failure.","authors":"Elia De Maria,&nbsp;Paolo Gallo,&nbsp;Michele Damiano,&nbsp;Giancarlo Scognamiglio,&nbsp;Ciro De Simone,&nbsp;Salvatore Nilo,&nbsp;Pasquale Guarini,&nbsp;Giosuè Mascioli,&nbsp;Antonio Curnis","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Background: </strong>Cardiac resynchronization therapy (CRT) is useful for the treatment of severe congestive heart failure. Unfortunately up to 30% of patients could be non-responders. The aim of our study was to find parameters to predict responsiveness to CRT.</p><p><strong>Methods: </strong>Fifteen patients (9 males, 6 females, mean age 67.3 +/- 7.8 years, range 52-83 years) with dilated cardiomyopathy, NYHA functional class III-IV, left ventricular (LV) ejection fraction < 35% and QRS > or = 110 ms, underwent CRT. All the patients had echocardiographic evidence of systolic dys-synchrony.</p><p><strong>Results: </strong>One patient died of electromechanical dissociation. The remaining 14 patients maintained biventricular stimulation at 6 months; mean QRS width decreased from 156 to 132 ms (p < 0.001). Ten patients (71%) were considered responders because of a reduction in LV end-systolic volume > 15%. In non-responders (4 patients, 29%) LV end-systolic volume was stable in 3 patients and increased in 1. LV ejection fraction significantly increased only in responders (p < 0.001). Responders had more severe pre-pacing dyssynchrony than non-responders (p < 0.001). Inter- (p = 0.002) and intraventricular dyssynchrony (p = 0.003) did significantly reduce after CRT only in responders. On multiple regression analysis there were two independent predictors of reverse remodeling after pacing: the baseline mitral QS-tricuspid QS (QSm-QSt) time (B = -1.7, p = 0.005) and the intraventricular dyssynchrony index (B = -1.55, p = 0.007). Pre-implant QSm-QSt of 38 ms correctly identified the two groups: responders had a value > 38 ms and non-responders < 38 ms. The pre-implant intraventricular dyssynchrony index of 28 ms was the cut-off value: responders had an index > 28 ms, non-responders < 28 ms.</p><p><strong>Conclusions: </strong>In the literature a tissue Doppler imaging index of intraventricular dyssynchrony evaluated before implantation is used to select responders to CRT. In our work we studied interventricular and intraventricular dyssynchrony, and both the QSm-QSt time and the standard deviation of the 12 LV segment QS time were correctly able to identify responders.</p>","PeriodicalId":80289,"journal":{"name":"Italian heart journal : official journal of the Italian Federation of Cardiology","volume":"6 9","pages":"734-9"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25624616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A difficult diagnosis: right unilateral cardiogenic pulmonary edema. Usefulness of biochemical markers of heart failure for the correct diagnosis.","authors":"Antonio D'Aloia,&nbsp;Pompilio Faggiano,&nbsp;Loretta Brentana,&nbsp;Alessandra Boldini,&nbsp;Roberto Procopio,&nbsp;Marco Racheli,&nbsp;Livio Dei Cas","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We describe a case of unilateral pulmonary edema occurring in a young woman affected by hypertrophic cardiomyopathy complicated by acute worsening of mitral regurgitation. The relevant role of biochemical markers of heart failure, such as brain natriuretic peptide and carbohydrate antigen 125, in clarifying the final diagnosis of cardiogenic pulmonary edema and modifying treatment accordingly is emphasized.</p>","PeriodicalId":80289,"journal":{"name":"Italian heart journal : official journal of the Italian Federation of Cardiology","volume":"6 9","pages":"771-4"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25626754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brugada syndrome and neurally mediated susceptibility.","authors":"Nicolino Patruno,&nbsp;Daniele Pontillo,&nbsp;Renato Anastasi,&nbsp;Lorenzo Sunseri,&nbsp;Luigi Giamundo,&nbsp;Giovanni Ruggeri","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The risk of sudden death in patients with Brugada syndrome (BS) is still unclear. Moreover, particular clinical conditions may have a confounding effect on the diagnostic and therapeutic approach. We report the case of a 27-year-old man with a clinical history of suspected neurally mediated syncope and typical ECG features of BS. The tilt table test showed a type I, mixed, positive response. The electrophysiological study (EPS) disclosed a peculiar ventricular irritability with the induction of a life-threatening arrhythmia. After the implantation of a cardioverter-defibrillator an episode of ventricular fibrillation during sleep at night was correctly identified and treated by the device. The association between neurally mediated susceptibility and the typical ECG abnormalities of BS is not an unexpected event in young subjects. The misjudgment of the pathophysiological mechanism of syncopal episodes may lead, on one hand, to overlook the risk of sudden death and, on the other, to pursue inappropriate therapeutic measures. The application of a tailored diagnostic work-up based on currently available guidelines may be useful to overcome the clinical and therapeutic dilemma.</p>","PeriodicalId":80289,"journal":{"name":"Italian heart journal : official journal of the Italian Federation of Cardiology","volume":"6 9","pages":"761-4"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25626752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of pulmonary regurgitation and age at surgical repair on textural and functional right ventricular myocardial properties in patients with tetralogy of Fallot.","authors":"Giuseppe Pacileo,&nbsp;Giuseppe Limongelli,&nbsp;Marina Verrengia,&nbsp;Tiziana Miele,&nbsp;Giulia Cesare,&nbsp;Paolo Calabrò,&nbsp;Giovanni Di Salvo,&nbsp;Fabiana Cerrato,&nbsp;Roberta Ancona,&nbsp;Raffaele Calabrò","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Background: </strong>The aim of this study was to identify non-invasively the potential impact of pulmonary regurgitation and age at surgical repair on the right ventricular (RV) textural and functional myocardial properties in patients operated on for tetralogy of Fallot (TOF).</p><p><strong>Methods: </strong>We assessed the average intensity (Int.(1B)) and the cyclic variation (CV(IB)) of the echocardiographic backscatter curve in 30 TOF patients (mean age 16.2 +/- 8.3 years), who had undergone corrective surgery (mean age at repair 3.2 +/- 2.6 years, range 0.2-11 years). They were divided into three age- and body surface area (BSA)-matched subgroups according to the results of the surgical repair: 12 patients had no significant postsurgical sequelae (group I), 12 patients had isolated moderate-severe pulmonary regurgitation (group II), and 6 patients had pulmonary regurgitation associated with significant (> 30 mmHg) RV outflow tract obstruction (group III). In addition, 30 age-, sex- and BSA-matched normal subjects were identified as the control group.</p><p><strong>Results: </strong>In our study population, CV(IB) was lower (7.86 +/- 2.5 vs 10.6 +/- 1.4 dB, p < 0.001) and Int.IB higher (-18.6 +/- 4.1 vs -21 +/- 2.8 dB, p = 0.01) compared to the control group. Comparison between the control group and each subgroup of TOF patients showed: a) comparable values of CV(IB) and Int.(IB) in group I (10.6 +/- 1.4 vs 9.4 +/- 2.3 dB, p = 0.07; and -21 +/- 2.8 vs -21.4 +/- 2.3 dB, p = 0.7, respectively); b) Int.(IB) was significantly different only in group III (-21 +/- 2.8 vs -13.3 +/- 4.6 dB, p < 0.0001), c) CV(IB) was different either in group II or III (10.6 +/- 1.4 vs 7.42 +/- 2, p < 0.001; and 10.6 +/- 1.4 vs 5.56 +/- 1.8, p < 0.001, respectively). In addition, comparison of integrated backscatter indexes among the TOF subgroups revealed significant differences of CV(IB) between group I and II (9.4 +/- 2.4 vs 7.4 +/- 2, p = 0.03) and between group I and III (9.4 +/- 2.4 vs 5.56 +/- 1.8, p = 0.004), and of Int.(IB) between group I and III (-21.4 +/- 2.3 vs -13.3 +/- 4.66, p < 0.001) and between group II and III (-21.4 +/- 2.3 vs -18.6 +/- 2.8, p = 0.006). Group III patients, who had the most significant RV dilation, expressed as the ratio between RV and left ventricular end-diastolic diameter (0.55 +/- 0.8) compared to group II (0.67 +/- 0.11, p = 0.038) and group I (0.55 +/- 0.87, p < 0.001), showed the lowest values of CV(IB) (5.56 +/- 1.8 dB) and the highest values of Int.(IB) (-13.3 +/- 4.6 dB) Finally, in our study population, both the degree of RV dilation and the age at surgical repair significantly correlated with Int.(IB) (r = 0.49 and r = 0.4, p = 0.06 and p = 0.033, respectively) and inversely correlated with CV(IB) (r = -0.55 and r = -0.53, p = 0.002 and p = 0.003, respectively).</p><p><strong>Conclusions: </strong>In patients operated on for TOF: a) integrated backscatter analysis may identify patients with significant RV my","PeriodicalId":80289,"journal":{"name":"Italian heart journal : official journal of the Italian Federation of Cardiology","volume":"6 9","pages":"745-50"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25626749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prognostic role of non-sustained ventricular tachycardia in a large cohort of patients with idiopathic dilated cardiomyopathy.","authors":"Massimo Zecchin,&nbsp;Andrea Di Lenarda,&nbsp;Dario Gregori,&nbsp;Michele Moretti,&nbsp;Mauro Driussi,&nbsp;Aneta Aleksova,&nbsp;Dorita Chersevani,&nbsp;Gastone Sabbadini,&nbsp;Gianfranco Sinagra","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Background: </strong>The identification of patients with idiopathic dilated cardiomyopathy (IDC) at higher risk of sudden death (SD) is still an unsolved issue, and the role of non-sustained ventricular tachycardia (NSVT) uncertain.</p><p><strong>Methods: </strong>The effect of NSVT on total mortality, SD and life-threatening arrhythmias was evaluated in 554 patients with IDC on optimal medical treatment and at long-term follow-up (81 +/- 58 months).</p><p><strong>Results: </strong>At diagnosis, 240 patients (43%) had NSVT at Holter monitoring and 314 (57%) did not. During follow-up, 189 patients (5/100 patients-year) died or underwent heart transplantation; SD occurred in 53 patients (1.4/100 patients-year); SD + non-fatal ventricular arrhythmias occurred in 75 patients (2/100 patients-year). Patients with and without NSVT at diagnosis had the same 5-year transplant-free survival rate (76 vs 76%, p = NS) and a similar incidence of SD (10 vs 7%, p = NS). The length and rate of NSVT did not show any significant relationship with the outcome. Only heart failure symptoms (NYHA class III-IV) (hazard ratio [HR] 1.9, p = 0.015) and severe left ventricular impairment (left ventricular ejection fraction < or = 0.30 and left ventricular end-diastolic diameter > or = 70 mm) (HR 2.7, p < 0.0001) were independently associated with higher SD risk. At multivariate analysis the presence of frequent NSVT episodes (> or = 3 runs/day) was associated with an increased risk of total mortality (HR 1.68, p = 0.041) and of major ventricular arrhythmias (HR 2.11, p = 0.037), but only in the subgroup of patients with severe left ventricular impairment.</p><p><strong>Conclusions: </strong>Patients with advanced heart failure symptoms, severe left ventricular dysfunction and dilation had a higher risk of SD independently of NSVT. The finding of more frequent NSVT was associated with an increased risk of all-cause mortality and of major ventricular arrhythmias in patients with severe left ventricular impairment.</p>","PeriodicalId":80289,"journal":{"name":"Italian heart journal : official journal of the Italian Federation of Cardiology","volume":"6 9","pages":"721-7"},"PeriodicalIF":0.0,"publicationDate":"2005-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"25624612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}