***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVES We tested whether an assessment of myocardial scarring by cardiac magnetic resonance imaging ( MRI ) would improve risk stratification in patients evaluated for implantable cardioverter-defibrillator ( ICD ) implantation . BACKGROUND Current sudden cardiac death risk stratification emphasizes left ventricular ejection fraction ( LVEF ) ; however , most patients suffering sudden cardiac death have a preserved LVEF , and many with poor LVEF do not benefit from ICD prophylaxis . METHODS One hundred thirty-seven patients undergoing evaluation for possible ICD placement were prospect ively enrolled and underwent cardiac MRI assessment of LVEF and scar . The pre-specified primary endpoint was death or appropriate ICD discharge for sustained ventricular tachyarrhythmia . RESULTS During a median follow-up of 24 months the primary endpoint occurred in 39 patients . Whereas the rate of adverse events steadily increased with decreasing LVEF , a sharp step-up was observed for scar size > 5 % of left ventricular mass ( hazard ratio [ HR ] : 5.2 ; 95 % confidence interval [ CI ] : 2.0 to 13.3 ) . On multivariable Cox proportional hazards analysis , including LVEF and electrophysiological- study results , scar size ( as a continuous variable or dichotomized at 5 % ) was an independent predictor of adverse outcome . Among patients with LVEF > 30 % , those with significant scarring ( > 5 % ) had higher risk than those with minimal or no ( ≤5 % ) scarring ( HR : 6.3 ; 95 % CI : 1.4 to 28.0 ) . Those with LVEF > 30 % and significant scarring had risk similar to patients with LVEF ≤30 % ( p = 0.56 ) . Among patients with LVEF ≤30 % , those with significant scarring again had higher risk than those with minimal or no scarring ( HR : 3.9 ; 95 % CI : 1.2 to 13.1 ) . Those with LVEF ≤30 % and minimal scarring had risk similar to patients with LVEF > 30 % ( p = 0.71 ) . CONCLUSIONS Myocardial scarring detected by cardiac MRI is an independent predictor of adverse outcome in patients being considered for ICD placement . In patients with LVEF > 30 % , significant scarring ( > 5 % LV ) identifies a high-risk cohort similar in risk to those with LVEF ≤30 % . Conversely , in patients with LVEF ≤30 % , minimal or no scarring identifies a low-risk cohort similar to those with LVEF > 30 % Background Heart failure treatment depends partly on the underlying cause of the disease . We evaluated cardiovascular magnetic resonance ( CMR ) for the problem of differentiating dilated cardiomyopathy ( DCM ) from left ventricular ( LV ) dysfunction caused by coronary artery disease ( CAD ) . Methods and Results Late gadolinium enhancement with CMR was performed in 90 patients with heart failure and LV systolic dysfunction ( 63 patients with DCM and unobstructed coronary arteries and 27 with significant CAD at angiography ) . We also studied 15 control subjects with no coronary risk factors and /or unobstructed coronary arteries . None ( 0 % ) of the control subjects had myocardial gadolinium enhancement ; however , all patients ( 100 % ) with LV dysfunction and CAD had enhancement , which was subendocardial or transmural . In patients with DCM , there were 3 findings : no enhancement ( 59 % ) ; myocardial enhancement indistinguishable from the patients with CAD ( 13 % ) ; and patchy or longitudinal striae of midwall enhancement clearly different from the distribution in patients with CAD ( 28 % ) . Conclusions Gadolinium CMR is a powerful technique to distinguish DCM from LV dysfunction related to CAD and yields new insights in DCM . These data suggest that using the coronary angiogram as the arbiter for the presence of LV dysfunction caused by CAD could have lead to an incorrect assignment of DCM cause in 13 % of patients , possibly because of coronary recanalization after infa rct ion . The midwall myocardial enhancement in patients with DCM is similar to the fibrosis found at autopsy ; it has not previously been visualized in vivo and warrants further investigation . CMR may become a useful alternative to routine coronary angiography in the diagnostic workup of DCM . ( Circulation . 2003;108:54‐59 . Background —The underlying pathophysiology of heart failure with preserved ejection fraction ( HFPEF ) is incompletely understood , but myocardial extracellular matrix accumulation is thought to play a major role . Our aims were to estimate myocardial extracellular matrix using cardiac magnetic resonance T1 mapping and to assess the relationship between pathobiology/pathophysiology and prognosis . Methods and Results — Patients with suspected HFPEF ( n=100 ) were enrolled in this prospect i ve , observational study . Confirmatory diagnostic tests , cardiac magnetic resonance imaging including T1 mapping , and invasive hemodynamic assessment s were performed at baseline . Sixty-one patients with confirmed HFPEF entered a longitudinal outcome -monitoring phase ( mean , 22.9±5.0 months ) , during which 16 had a cardiac event . Cardiac magnetic resonance T1 time ( hazard ratio , 0.99 ; 95 % confidence interval , 0.98–0.99 ; P=0.046 ) , left atrial area ( hazard ratio , 1.08 ; 95 % confidence interval , 1.03–1.13 ; P<0.01 ) , and pulmonary vascular resistance ( hazard ratio , 1.01 ; 95 % confidence interval , 1.00–1.01 ; P=0.03 ) were significantly associated with cardiac events . Patients with T1 times below the median ( < 388.3 ms ) were at greater risk of cardiac events than the rest of the group ( P<0.01 ) . Extracellular matrix of left ventricular biopsies ( n=9 ) , quantified by TissueFAXS technology correlated with T1 time ( R=0.98 ; P<0.01 ) . T1 time also correlated with right ventricular – pulmonary arterial coupling ( pulmonary vascular resistance : R=−0.36 ; P<0.01 ; right ventricular ejection fraction : R=0.28 ; P=0.01 ) . Conclusions —In the present preliminary study , cardiac magnetic resonance postcontrast T1 time is associated with prognosis in HFPEF , suggesting postcontrast T1 as possible biomarker for HFPEF Background : Because of specific method ological difficulties in conducting r and omized trials , surgical research remains dependent predominantly on observational or non‐r and omized studies . Few vali date d instruments are available to determine the method ological quality of such studies either from the reader 's perspective or for the purpose of meta‐ analysis . The aim of the present study was to develop and vali date such an instrument Background Following publication of the PRISMA statement , the UK Centre for Review s and Dissemination ( CRD ) at the University of York in Engl and began to develop an international prospect i ve register of systematic review s with health-related outcomes . The objectives were to reduce unplanned duplication of review s and provide transparency in the review process , with the aim of minimizing reporting bias . Methods An international advisory group was formed and a consultation undertaken to establish the key items necessary for inclusion in the register and to gather views on various aspects of functionality . This article describes the development of the register , now called PROSPERO , and the process of registration . Results PROSPERO offers free registration and free public access to a unique prospect i ve register of systematic review s across all areas of health from all around the world . The dedicated web-based interface is electronically search able and available to all prospect i ve registrants . At the moment , inclusion in PROSPERO is restricted to systematic review s of the effects of interventions and strategies to prevent , diagnose , treat , and monitor health conditions , for which there is a health-related outcome .Ideally , registration should take place before the research ers have started formal screening against inclusion criteria but review s are eligible as long as they have not progressed beyond the point of completing data extraction .The required data set captures the key attributes of review design as well as the administrative details necessary for registration .Su bmi tted registration forms are checked against the scope for inclusion in PROSPERO and for clarity of content before being made publicly available on the register , rejected , or returned to the applicant for clarification . The public records include an audit trail of major changes to planned methods , details of when the review has been completed , and links to result ing publications when provided by the authors . Conclusions There has been international support and an enthusiastic response to the principle of prospect i ve registration of protocol s for systematic review s and to the development of PROSPERO .In October 2011 , PROSPERO contained 200 records of systematic review s being undertaken in 26 countries around the world on a diverse range of interventions OBJECTIVES We studied the prognostic implication s of midwall fibrosis in dilated cardiomyopathy ( DCM ) in a prospect i ve longitudinal study . BACKGROUND Risk stratification of patients with nonischemic DCM in the era of device implantation is problematic . Approximately 30 % of patients with DCM have midwall fibrosis as detected by late gadolinium-enhancement ( LGE ) cardiovascular magnetic resonance ( CMR ) , which may increase susceptibility to arrhythmia and progression of heart failure . METHODS Consecutive DCM patients ( n = 101 ) with the presence or absence of midwall fibrosis  were followed up prospect ively for 658 + /- 355 days for events . RESULTS Midwall fibrosis was present in 35 % of patients and was associated with a higher rate of the predefined primary combined end point of all-cause death and hospitalization for a cardiovascular event ( hazard ratio 3.4 , p = 0.01 ) . Multivariate analysis showed midwall fibrosis as the sole significant predictor of death or hospitalization . However , there was no significant difference in all-cause mortality between the 2 groups . Midwall fibrosis also predicted secondary outcome measures of sudden cardiac death ( SCD ) or ventricular tachycardia ( VT ) ( hazard ratio 5.2 , p = 0.03 ) . Midwall fibrosis remained predictive of SCD/VT after correction for baseline differences in left ventricular ejection fraction between the 2 groups . CONCLUSIONS In DCM , midwall fibrosis determined by CMR is a predictor of the combined end point of all-cause mortality and cardiovascular hospitalization , which is independent of ventricular remodeling . In addition , midwall fibrosis by CMR predicts SCD/VT . This suggests a potential role for CMR in the risk stratification of patients with DCM , which may have value in determining the need for device therapy 
    Output:
    
Conclusion In conclusion , native T1 values were significantly different between NIC patients and controls .
Native T1 mapping may be a useful noninvasive method to detect diffuse myocardial fibrosis in NIC patients