Cardiac electrophysiology review最新文献

{"title":"How should subgroup analyses affect clinical practice? Insights from the Metoprolol Succinate Controlled-Release/Extended-Release Randomized Intervention Trial in Heart Failure (MERIT-HF).","authors":"John Wikstrand,&nbsp;Hans Wedel,&nbsp;Jalal Ghali,&nbsp;Prakash Deedwania,&nbsp;Björn Fagerberg,&nbsp;Sidney Goldstein,&nbsp;Stephen Gottlieb,&nbsp;Ake Hjalmarson,&nbsp;John Kjekshus,&nbsp;Finn Waagstein","doi":"10.1023/B:CEPR.0000012438.04416.00","DOIUrl":"https://doi.org/10.1023/B:CEPR.0000012438.04416.00","url":null,"abstract":"<p><strong>Context: </strong>The Metoprolol CR/XL Randomized Intervention Trial in Chronic Heart Failure (MERIT-HF), the Cardiac Insufficiency Bisoprolol Study II (CIBIS-II), and the Carvedilol Prospective Randomized Cumulative Survival Study (COPERNICUS) have all demonstrated highly significant positive effects on total mortality as well as total mortality plus all-cause hospitalization in patients with heart failure. While none of these trials are large enough to provide definitive results in any particular subgroup, it is of interest for physicians to examine the consistency of results as regards efficacy and safety for various subgroups or risk groups.</p><p><strong>Objective: </strong>To summarize results from both predefined as well as post-hoc subgroup analyses performed in the MERIT-HF trial, and to provide guidance as to whether any subgroup is at increased risk, despite an overall strongly positive effect, and to discuss the difficulties and limitations in conducting such subgroup analyses. For some subgroups we performed metaanalyses with data from the CIBIS II and COPERNICUS trials in order to obtain more robust data on mortality in subgroups with a small number of deaths (e.g. for women).</p><p><strong>Setting: </strong>MERIT-HF was run in 14 countries, and randomized a total of 3,991 patients with symptomatic systolic heart failure (NYHA class II to IV with ejection fraction < or =0.40). Treatment was initiated with a very low dose with careful titration to a maximum target dose of 200 mg metoprolol succinate controlled release/extended release (CR/XL), or highest tolerated dose.</p><p><strong>Main outcome measures: </strong>Total mortality (first primary endpoint), total mortality plus all-cause hospitalization (second primary endpoint), and total mortality plus hospitalization for heart failure (first secondary endpoint) analyzed on a time to first event basis.</p><p><strong>Results: </strong>Overall, MERIT-HF demonstrated a 34% reduction in total mortality ( p = 0.00009 nominal) and a 19% reduction for mortality plus all-cause hospitalization ( p = 0.00012). The first secondary endpoint of mortality plus hospitalization for heart failure was reduced by 31% ( p = 0.0000008). The results were remarkably consistent for both primary outcomes and the first secondary outcome across all predefined subgroups as well as nearly all post-hoc subgroups. Metoprolol CR/XL has been very well tolerated, overall as well as in all subgroups analyzed. Overall 87% of the patients reached a dose of 100 mg or more of metoprolol CR/XL once daily, and 64% reached the target dose of 200 mg once daily.</p><p><strong>Conclusion: </strong>Our results show that when carefully titrated, metoprolol CR/XL can safely be instituted for the overwhelming majority of outpatients with clinically stable systolic heart failure, with minimal side effects or deterioration. The time has come to overcome the barriers that physicians perceive to beta-blocker treatment, and ","PeriodicalId":80888,"journal":{"name":"Cardiac electrophysiology review","volume":"7 3","pages":"264-75"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/B:CEPR.0000012438.04416.00","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24177919","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":"Time to first recurrence as a trial endpoint: time to change?","authors":"Rahul Mehra","doi":"10.1023/B:CEPR.0000012396.77522.6e","DOIUrl":"https://doi.org/10.1023/B:CEPR.0000012396.77522.6e","url":null,"abstract":"<p><p>There has been a rapidly increasing interest in developing new therapies for management of atrial fibrillation. The optimal method for evaluating their efficacy is by measuring changes in outcomes such as mortality, quality of life or cost of care; requiring trials of large sample size. In order to reduce the sample size, there is a need to develop appropriate surrogate endpoints. \"Is time to first recurrence of symptomatic atrial fibrillation\" an appropriate surrogate endpoint for quality of life? Since a surrogate endpoint must capture the net effect of the treatment, it was assumed (a) that frequency of symptomatic episodes captures the net effect on quality of life and (b) \"time to first recurrence\" is a measure of the frequency of symptomatic episodes. The effect of frequency of symptomatic episodes or their duration and symptom severity on quality of life has not been evaluated. \"Time to first symptomatic recurrence\" was proposed because data from a few patients demonstrated that symptomatic atrial fibrillation episodes arose independently and randomly and could be represented mathematically by a Poisson distribution. Recent data from a greater number of patients with implantable devices that detect symptomatic and asymptomatic episodes of atrial tachyarrhythmias indicate that these episodes tend to cluster in time and cannot be well represented by a Poisson distribution. Because all atrial tachyarrhythmia episodes do not follow a Poisson distribution, it is unlikely that only symptomatic episodes would follow the same distribution, although this needs to be proved. A non-Poisson distribution requires a larger sample to detect differences in clinical trials. This should be taken into consideration when designing prospective trials. Alternative methods may include measuring frequency of symptomatic episodes as well their severity and duration. In patients with implanted devices, total duration of time spent in atrial tachyarrhythmias or objective measures of rate control should also be evaluated as surrogate endpoints. If surrogate endpoints cannot be developed, changes in clinical outcomes will need to be demonstrated to evaluate therapeutic efficacy.</p>","PeriodicalId":80888,"journal":{"name":"Cardiac electrophysiology review","volume":"7 3","pages":"280-4"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/B:CEPR.0000012396.77522.6e","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24177921","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":"Azimilide for atrial fibrillation: clinical trial results and implications.","authors":"Edward L C Pritchett,&nbsp;Stephen R Marcello","doi":"10.1023/B:CEPR.0000012385.15778.d2","DOIUrl":"https://doi.org/10.1023/B:CEPR.0000012385.15778.d2","url":null,"abstract":"<p><p>Azimilide dihydrochloride (or azimilide) is a class III antiarrhythmic drug currently under investigation that has been tested in atrial fibrillation in four randomized, placebo-controlled clinical trials to assess efficacy and dose range. These investigational trials showed that doses of azimilide 100 and 125 mg once daily prolonged the time to symptomatic arrhythmia recurrence in patients with a history of symptomatic atrial fibrillation, atrial flutter or both. Doses of 75 mg or less were not useful in this indication. Safety of azimilide has been examined in several different types of studies. In a large randomized clinical trial of post-infarct patients, azimilide neither increased nor decreased mortality risk. In patients with supraventricular arrhythmias, the most common adverse effects reported by patients on azimilide were approximately equal in frequency with those on placebo: headache, asthenia, infection, diarrhea and dizziness. Infrequent cases of torsade de pointes and severe neutropenia were reported in patients taking azimilide. Azimilide is an investigational antiarrhythmic drug that has shown efficacy in patients with atrial fibrillation.</p>","PeriodicalId":80888,"journal":{"name":"Cardiac electrophysiology review","volume":"7 3","pages":"215-9"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/B:CEPR.0000012385.15778.d2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24177467","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":"Rationale for the Atrial Fibrillation and Congestive Heart Failure (AF-CHF) trial.","authors":"Denis Roy","doi":"10.1023/B:CEPR.0000012383.63580.c8","DOIUrl":"https://doi.org/10.1023/B:CEPR.0000012383.63580.c8","url":null,"abstract":"<p><p>Congestive heart failure and atrial fibrillation (AF) are two important and growing problems in medicine and cardiology. Both conditions often coexist and complicate each other's management. Two therapeutic strategies are available for patients with AF and congestive heart failure: the first aims at restoring and maintaining sinus rhythm, whereas the second focuses exclusively on optimizing ventricular rate. Prior studies of AF and congestive heart failure were not randomized and most were retrospective. Although some studies suggested that AF had no effect on survival, in most recent large congestive heart failure trials, AF was reported to be an independent risk factor for mortality or major morbidity. The primary objective of the Atrial Fibrillation in Congestive Heart Failure (AF-CHF) trial is to compare the two widely used treatment strategies with respect to cardiovascular mortality. AF-CHF is a prospective, multicenter trial that will randomize 1450 CHF patients with left ventricular ejection fraction (LVEF) < or =35% and a documented recent episode of atrial fibrillation to either a rhythm control or a rate control strategy. From recent trial data, we anticipate an 18.75% 2-year cardiovascular mortality in the rate control arm and a 25% event reduction in the rhythm control group. As of December 2003, 960 patients have been randomized. Enrollment is expected to be completed in September 2004 with a minimum follow-up of 2 years.</p>","PeriodicalId":80888,"journal":{"name":"Cardiac electrophysiology review","volume":"7 3","pages":"208-10"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/B:CEPR.0000012383.63580.c8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24177465","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":"Angiotensin receptor blocker as adjunctive therapy for rhythm control in atrial fibrillation: results of the irbesartan-amiodarone trial.","authors":"Antonio H Madrid,&nbsp;Carlos Escobar,&nbsp;José María G Rebollo,&nbsp;Irene Marín,&nbsp;Enrique Bernal,&nbsp;Sebastián Nannini,&nbsp;Lilianna Limón,&nbsp;Jian Peng,&nbsp;Concepción Moro","doi":"10.1023/B:CEPR.0000012391.95928.d2","DOIUrl":"https://doi.org/10.1023/B:CEPR.0000012391.95928.d2","url":null,"abstract":"<p><p>Atrial fibrillation (AF) is a common arrhythmia associated with increased risk of stroke and mortality. The early appearance of electrical remodeling is followed by structural remodeling of the atrial tissue. Direct current cardioversion of persistent AF is the most effective treatment for the restoration of sinus rhythm, but it is hampered by a high percentage of recurrences. Recurrences may be the consequence of both electrical and structural remodeling. A study on the use of irbesartan to maintain sinus rhythm in patients with long-lasting persistent AF showed that this angiotensin II receptor blocker combined with amiodarone prolonged sinus rhythm after cardioversion. Irbesartan may have antifibrotic effects due not only to the ability to diminish the synthesis of collagen type I molecules but also to its capacity to stimulate the degradation of collagen type I fibers, as has been demonstrated with losartan, another angiotensin II receptor blocker. This suggests that efforts to reduce the structural changes that occur during AF may be more useful in preventing recurrences than efforts designed to minimize the electrical changes alone. The AFFIRM trial compared two approaches to the treatment of AF: cardioversion with antiarrhythmic drugs to maintain sinus rhythm and the use of rate-controlling drugs. The results show that management of AF with the rhythm-control strategy offers no survival advantage over the rate-control strategy. However, non-antiarrhythmic drugs to prevent recurrences, like irbesartan, were not controlled and amiodarone was used in a low percentage of the patients. The treatment strategies proposed in both AFFIRM and RACE, in our opinion, may not be the optimal. The modern clinical approach to AF involves an early intervention to restore sinus rhythm, therefore preventing atrial remodeling. The pretreatment of patients with AF who undergo electrical cardioversion is very important and will be the subject for continuous improvement.</p>","PeriodicalId":80888,"journal":{"name":"Cardiac electrophysiology review","volume":"7 3","pages":"243-6"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/B:CEPR.0000012391.95928.d2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24177915","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":"Biphasic versus monophasic shock waveform for conversion of atrial fibrillation.","authors":"Robert W Rho,&nbsp;Richard L Page","doi":"10.1023/B:CEPR.0000012398.01150.eb","DOIUrl":"https://doi.org/10.1023/B:CEPR.0000012398.01150.eb","url":null,"abstract":"<p><p>Cardioversion of atrial fibrillation (AF) using traditional monophasic shock waveform is unsuccessful in up to 20% of cases, and often requires several shocks of up to 360 J. Based on the success with biphasic shock waveform in converting ventricular fibrillation, it was postulated that biphasic shocks would allow cardioversion with lower energy. In a international multicenter, double-blind, randomized trial of 203 patients, damped sine wave monophasic shocks were compared with impedance-compensated truncated exponential biphasic waveform shocks. Patients received up to five shocks: 100 J, 150 J, 200 J, a fourth shock at maximum output for the initial waveform (200 J biphasic, 360 J monophasic) and a final cross-over shock at maximum output of the alternate waveform. For each energy level, the biphasic waveform compared favorably to the monophasic waveform in successful cardioversion (100 J: 60% versus 22%, P < 0.0001; 150 J: 77% versus 44%, p < 0.0001; 200 J: 90% versus 53%, p < 0.0001). Success with 200 J biphasic was equivalent to 360 J monophasic shock (91% versus 85%, p = 0.29). Patients randomized to biphasic waveform required fewer shocks and lower total energy delivered; in addition, this waveform was associated with less dermal injury and no blistering. Biphasic shocks converted AF present for less than 48 hours with 80% efficacy, but conversion of AF present for more than 48 hours and more than 1 year the success rate was only 63 and 20%, respectively. The results of this study is similar to other investigations comparing biphasic and monophasic shock waveforms for conversion of atrial fibrillation. We recommend starting with biphasic energy of 100 J for atrial fibrillation of less than 48 hours duration, but using higher energies (150 J, 200 J or greater) when AF has been present for longer periods.</p>","PeriodicalId":80888,"journal":{"name":"Cardiac electrophysiology review","volume":"7 3","pages":"290-1"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/B:CEPR.0000012398.01150.eb","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24177352","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":"An update on electrical cardioversion of atrial fibrillation.","authors":"Suneet Mittal,&nbsp;Kenneth M Stein,&nbsp;Steven M Markowitz,&nbsp;Sei Iwai,&nbsp;Amit Guttigoli,&nbsp;Bruce B Lerman","doi":"10.1023/B:CEPR.0000012397.29446.16","DOIUrl":"https://doi.org/10.1023/B:CEPR.0000012397.29446.16","url":null,"abstract":"<p><p>Atrial fibrillation is the most frequently encountered sustained arrhythmia in clinical practice. Electrical cardioversion of atrial fibrillation using damped sine wave shocks has been a mainstay of therapy for nearly 4 decades; its limitation remains a failure rate that approaches 20%. Although several alternatives have been proposed, including delivering 720 J shocks using dual monophasic defibrillators, ibutilide pretreatment and internal cardioversion, each of these approaches has significant limitations, which preclude its routine use. Recent data demonstrate that routine use of biphasic shocks for cardioversion of atrial fibrillation is associated with a marked improvement in cardioversion efficacy and suggest that biphasic shocks may be the preferred method for the transthoracic electrical cardioversion of atrial fibrillation.</p>","PeriodicalId":80888,"journal":{"name":"Cardiac electrophysiology review","volume":"7 3","pages":"285-9"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/B:CEPR.0000012397.29446.16","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24177351","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":"Role of dofetilide in patients with atrial fibrillation. Insights from the Symptomatic Atrial Fibrillation Investigative Research on Dofetilide (SAFIRE-D) study.","authors":"Steven N Singh","doi":"10.1023/B:CEPR.0000012387.04308.29","DOIUrl":"https://doi.org/10.1023/B:CEPR.0000012387.04308.29","url":null,"abstract":"<p><p>Dofetilide is a class III antiarrhythmic drug (potassium channel blocker) that has been approved by the regulatory agencies in the United States and throughout the world to convert atrial fibrillation and maintain sinus rhythm. Therapy is initiated in-hospital during heart rhythm monitoring. Doses are selected according to the QT interval and estimated creatinine clearance. In patients with heart failure and prior myocardial infarction, dofetilide was very effective in converting atrial fibrillation and maintaining normal sinus rhythm. In patients with persistent atrial fibrillation, dofetilide compared to placebo was significantly better in converting atrial fibrillation and maintaining sinus rhythm. This was especially true for the highest dose of 500 microg twice-a-day. Caution must be used when initiating dofetilide therapy to avoid torsade de pointes ventricular tachycardia, especially in patients with heart failure, hypertrophy, bradycardia and female gender.</p>","PeriodicalId":80888,"journal":{"name":"Cardiac electrophysiology review","volume":"7 3","pages":"225-8"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/B:CEPR.0000012387.04308.29","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24177469","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":"Beta blockers improve outcome in patients with heart failure and atrial fibrillation: U.S. carvedilol study.","authors":"Karthik Ramaswamy","doi":"10.1023/B:CEPR.0000012388.85901.1c","DOIUrl":"https://doi.org/10.1023/B:CEPR.0000012388.85901.1c","url":null,"abstract":"<p><p>Atrial fibrillation (AF) is present in a significant number of patients with heart failure (HF) caused by left ventricular systolic dysfunction and is associated with increased morbidity and mortality. The deleterious interaction of AF and HF is mediated through a number of mechanisms including hemodynamic alterations and activation of the sympathetic nervous system. Beta-blockers have been shown to improve symptoms and survival in patients with HF. In addition, beta-blockers have been used in patients with AF, primarily for rate control. A retrospective analysis of the U.S. Carvedilol Heart Failure Trial demonstrated that carvedilol improves outcomes in the high-risk subgroup of patients with HF and concomitant AF.</p>","PeriodicalId":80888,"journal":{"name":"Cardiac electrophysiology review","volume":"7 3","pages":"229-32"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/B:CEPR.0000012388.85901.1c","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24177470","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":"Antiarrhythmic surgery to cure atrial fibrillation--subgroups and postoperative management.","authors":"Thomas Deneke,&nbsp;Krishna Khargi,&nbsp;Peter H Grewe,&nbsp;Frank Kuschkowitz,&nbsp;Axel Laczkovics,&nbsp;Bernd Lemke","doi":"10.1023/B:CEPR.0000012394.73676.93","DOIUrl":"https://doi.org/10.1023/B:CEPR.0000012394.73676.93","url":null,"abstract":"<p><p>Antiarrhythmic surgical procedures to cure atrial fibrillation (AF) are widely used in cardiac surgery. Whereas the Cox maze procedure remains the highly effective gold-standard a variety of different antiarrhythmic procedures aim at reducing the extent and duration of the procedure. Antiarrhythmic procedures are especially effective in patients undergoing mitral valve surgery. In 110 patients with permanent AF undergoing various surgical procedures sinus rhythm was re-established in 75%. Subgroup analyses revealed no significant differences in rhythm or survival after antiarrhythmic intraoperative ablation indicating the usefulness and feasibility of this procedure in patients with a wide range of characteristics. Because conversion usually occurs spontaneously within the first 6 months and antiarrhythmic medication does not increase the incidence of conversion it seems reasonable to wait for spontaneous occurrence of sinus rhythm after antiarrhythmic intraoperative ablation. In patients with permanent AF undergoing open heart surgery additional antiarrhythmic procedures have been shown to be safe and effective.</p>","PeriodicalId":80888,"journal":{"name":"Cardiac electrophysiology review","volume":"7 3","pages":"259-63"},"PeriodicalIF":0.0,"publicationDate":"2003-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1023/B:CEPR.0000012394.73676.93","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"24177918","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}