***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: Background —Heart failure with preserved ejection fraction ( HF-nlEF ) is common in aged individuals with systolic hypertension and is frequently ascribed to diastolic dysfunction . We hypothesized that such patients also display combined ventricular-systolic and arterial stiffening that can exacerbate blood pressure lability and diastolic dysfunction under stress . Methods and Results —Left ventricular pressure-volume relations were measured in patients with HF-nlEF ( n=10 ) and contrasted with asymptomatic age-matched ( n=9 ) and young ( n=14 ) normotensives and age- and blood pressure-matched controls ( n=25 ) . End-systolic elastance ( stiffness ) was higher in patients with HF-nlEF ( 4.7±1.5 mm Hg/mL ) than in controls ( 2.1±0.9 mm Hg/mL for normotensives and 3.3±1.0 mm Hg/mL for hypertensives;P < 0.001 ) . Effective arterial elastance was also higher ( 2.6±0.5 versus 1.9±0.5 mm Hg/mL ) due to reduced total arterial compliance ; the latter inversely correlated with end-systolic elastance ( P = 0.0001 ) . Body size and stroke volumes were similar and could not explain differences in ventricular-arterial stiffening . HF-nlEF patients also displayed diastolic abnormalities , including higher left ventricular end-diastolic pressures ( 24.3±4.6 versus 12.9±5.5 mm Hg ) , caused by an upward-shifted diastolic pressure-volume curve . However , isovolumic relaxation and the early-to-late filling ratio were similar in age- and blood pressure-matched controls . Ventricular-arterial stiffening amplified stress-induced hypertension , which worsened diastolic function , and predicted higher cardiac energy costs to provide reserve output . Conclusion — Patients with HF-lnEF have systolic-ventricular and arterial stiffening beyond that associated with aging and /or hypertension . This may play an important pathophysiological role by exacerbating systemic load interaction with diastolic function , augmenting blood pressure lability , and elevating cardiac metabolic dem and under stress AIMS We used speckle tracking echocardiography ( STE ) to make a comparison between the effects of ageing and of heart failure with normal ejection fraction ( HfnEF ) on left ventricular ( LV ) torsion and strain patterns . METHODS AND RESULTS Forty patients with HfnEF , 27 young controls and 26 older controls , were prospect ively recruited . All subjects underwent clinical examination , 12-lead electrocardiogram , pulmonary function test , echocardiogram , and metabolic exercise test .  LV torsion increases with advancing age ( older controls vs. young controls , 2.2 + /- 0.9 vs. 1.4 + /- 0.8 degrees /cm ; P = 0.03 ) . Circumferential strain was enhanced in patients with HfnEF ( -24.7 + /- 4.7 vs. -20.0 + /- 4.9 % ; P = 0.003 ) . Rotational deformation delay ( time difference between peak basal rotation and peak apical rotation ) , global circumferential strain , E-velocity deceleration time , and LV end-diastolic volume index were independent predictors of LV torsion . LV torsion and body mass index were independent predictors of LV untwist rate . CONCLUSION Ageing is associated with increased LV torsion secondary to reduced rotational deformation delay and increased peak basal rotation . LV torsion and strain patterns in patients with HfnEF are similar to age-related changes apart from circumferential strain , which is enhanced in patients with HfnEF Heart failure with preserved left ventricular ejection fraction ( HFpEF ) is implicitly attributed to diastolic dysfunction , often recognized in elderly patients with hypertension , diabetes , and renal dysfunction . In these patients , left ventricular circumferential and longitudinal shortening is often impaired despite normal ejection fraction . The aim of this prospect i ve study was to analyze circumferential and longitudinal shortening and their relations in patients with nonischemic HFpEF .  Stress-corrected midwall shortening ( sc-MS ) and mitral annular peak systolic velocity ( S ' )  were measured in 60 patients ( mean age 73 ± 13 years ) with chronic nonischemic HFpEF in stable New York Heart Association functional class II or III and compared to the values in 120 healthy controls and 120 patients with hypertension without HFpEF .  Sc-MS was classified as low if < 89 % and S ' as low if < 8.5 cm/s ( the 10th-percentile values of healthy controls ) . Isolated low sc-MS was detected in 46 % of patients with HFpEF , 27 % of patients with hypertension , and 2 % of controls ; isolated low S ' was detected in 11 % of patients with HFpEF , 7 % of patients with hypertension , and 5 % of controls ; and combined low sc-MS and low S ' was detected in 26 % of patients with HFpEF , 9 % of patients with hypertension , and 5 % of controls ( HFpEF vs others , all p values < 0.001 ) . Thus , any alteration of systolic function was found in 83 % of patients with HFpEF . The relation between sc-MS and S ' was nonlinear ( cubic ) . Changes in S ' within normal values corresponded to negligible variations in sc-MS , whereas the progressive decrease below 8.5 cm/s was associated with substantial decrease in sc-MS . In conclusion , circumferential and /or longitudinal systolic dysfunction is present in most patients with HFpEF . Circumferential shortening normalized by wall stress identifies more patients with concealed left ventricular systolic dysfunction than longitudinal shortening OBJECTIVES The purpose of this study was to define age- , sex- , and ethnicity-specific reference values for  3-dimensional echocardiographic ( 3DE ) left ventricular ( LV ) volumes and LV ejection fraction ( LVEF ) in a large cohort of European white and Indian Asian subjects . BACKGROUND Transthoracic 3DE imaging is recommended for the routine evaluation of LV volumes and function . However , there remains a lack of population -based reference values for 3DE LV volumes and LVEF , hindering adoption of this technique into routine clinical practice . METHODS We identified subjects from the LOLIPOP ( London Life Sciences Prospect i ve Population ) study who were free of clinical cardiovascular disease , hypertension , and type 2 diabetes . All subjects underwent  transthoracic 2-dimensional and 3D echocardiography for quantification of LV end-systolic volume index , LV end-diastolic volume index , and LVEF . RESULTS 3DE image quality was satisfactory in 978 subjects ( 89 % ) for the purpose s of LV volumetric analysis . Indexed 3DE LV volumes were significantly smaller in female compared with male subjects and in Indian Asians compared with European whites . Upper limit of normal ( mean ± 2 SD ) reference values for the LV end-systolic volume index and LV end-diastolic volume index for the 4 ethnicity-sex subgroups were , respectively , as follows : European white men , 29 ml/m(2 ) and 67 ml/m(2 ) ; Indian Asian men , 26 ml/m(2 ) and 59 ml/m(2 ) ; European white women , 24 ml/m(2 ) and 58 ml/m(2 ) ; Indian Asian women , 23 ml/m(2 ) and 55 ml/m(2 ) , respectively . Compared with 3DE studies , 2-dimensional echocardiography underestimated the LV end-systolic volume index and LV end-diastolic volume index by an average of 2.0 ml/m(2 ) and 4.7 ml/m(2 ) , respectively . LVEF was similar between in all 4 groups and between 2- and 3-dimensional techniques , with a lower cutoff of 52 % for the whole cohort . CONCLUSIONS These reference values are based on the largest 3DE study performed to date that should facilitate the st and ardization of the technique and encourage its adoption for the routine assessment of LV volumes and LVEF in the clinical echocardiography laboratory . This study supports the application of ethnicity-specific reference values for indexed LV volumes Objectives : Increased homocysteine ( HCY ) levels are associated with an increased risk of cardiovascular disease . Plasma HCY is increased in chronic heart failure ( CHF ) patients , and previous studies suggest that hyperhomocysteinemia causes adverse cardiac remodeling and affects pump function . We aim ed to evaluate the HCY levels in patients with diastolic heart failure with preserved left ventricular ejection fraction ( LVEF ) . Methods : We prospect ively studied 68 patients ( 39 females and 29 males ) who were hospitalized for symptomatic heart failure , as well as 40 age- and sex-matched healthy subjects who comprised the control group . CHF was diagnosed in all cases based on Framingham diagnostic criteria . CHF with preserved LVEF was defined as cases with CHF with an LVEF of 50 % or more . Patients with regional left ventricular wall motion abnormalities , atrial fibrillation , and renal failure were excluded . Results : The mean age was 65.5 ± 9.6 years in the heart failure group and 65.2 ± 9.7 years in the control group . The mean  LVEF was 59.8 ± 5.3 in the heart failure group and 61.4 ± 5.2 in the control group . The mean total fasting HCY concentrations were significantly higher in patients with heart failure ( 16.9 ± 5.27 µmol/l vs. 10.15 ± 3.49 µmol/l , respectively ; p < 0.001 ) . Multiple regression analysis indicated that NT-proBNP , hs-CRP , E/A ratio , and HbA1C were independently associated with hyperhomocysteinemia . Conclusions : Our results suggest that hyperhomocysteinemia is prevalent in heart failure with preserved ejection fraction . Larger scale studies are needed to clarify its pathogenic mechanisms and effects on the natural history of heart failure 
    Output:
    
This analysis showed that EF in HFPEF is on average " greater-than-normal " .
This phenomenon may be related to an underlying adaptive mechanism occurring in HFPEF .