congestive heart failure ( hf ) is classified according to clinical and instrumental findings into four stages . stage a and b being the first two are characterized by the presence of clinical risk factors and structural abnormalities , respectively , asymptomatically . these silent abnormalities may lead over a time to symptomatic left ventricular dysfunction ( lvd ) ( stage c and d ) . early detection of subclinical form of lvd may lead to establish an early protective treatment and potentially delay the development into overt hf . metabolic syndrome ( ms ) is a cluster of several risk factors for cardiovascular diseases associated with an higher incidence of symptomatic hf and cardiovascular events . data from third national health and nutrition examination survey ( nhanes iii ) showed that patients with ms had nearly twice the likelihood of self - reported hf , suggesting that ms may serve as a surrogate indicator for the association between insulin resistance and hf . moreover , each individual marker of ms is inferior to ms itself in identifying subtle cardiac dysfunction . however , the prevalence of asymptomatic lv systolic and/or diastolic dysfunction is not well established in patients with ms at stage a or b of hf . aim of this study is to evaluate left ventricular systolic and/or diastolic abnormalities in a large sample of patients with ms and without symptoms of hf . total of 6422 consecutive patients ( median age 59 years , interquartiles range : 48 - 68 ; men 3364 ) referred for a routine transthoracic examination to 75 national echocardiographic laboratories , were enrolled in the study . all laboratories were selected according to the competence level of the operators , which is level 3 in agreement with the american society of echocardiography ( ase ) requirements . detailed history of all the patients were taken , with focus on cardiovascular risk factors . exclusion criteria were : dyspnoea , valvular heart disease at least of moderate degree , previous valvular heart surgery , coronary artery by - pass surgery within the previous six months . in this study , we adopted the main definition of ms in accordance with the american heart association ( aha)/national heart , lung , and blood institute ( nhlbi ) scientific statements . we diagnosed ms with the presence of at least three of the following : hypertension , dyslipidemia , glucose intolerance and obesity with cutoff points consistent with the national cholesterol education program s adult treatment panel iii ( atp iii ) report , modified with body mass index ( bmi ) in place of waist circumference . hypertension was defined as systolic bp  140 mm hg , diastolic bp  90 mm hg , or self - reported antihypertensive medication use during the 2-week period before the clinical examination . dyslipidemia was defined as a low hdl cholesterol level ( < 40 mg / dl in men and < 50 mg / dl in women ) or as an elevated triglyceride level (  150 mg / dl ) . glucose intolerance was defined by the presence of diabetes ( self - reported physician diagnosis of diabetes , use of insulin or oral hypoglycemic medication , or fasting glucose level  126 mg / dl ) or impaired fasting glucose ( fasting glucose level  110 mg / dl ) according to american diabetes association criteria . subjects having three or more of the above mentioned criteria were classified as having ms . consistently with other major studies , we used bmi because we could not obtain waist circumference measurements for the entire study sample . the waist circumference criteria used in the atp iii definition were replaced with cutoff points for bmi ( 28.8 kg / m for men and 26.7 kg / m for women ) , as in previous studies . all patients underwent physical examination , 12-lead electrocardiography , and a complete transthoracic echocardiographic examination , according to the standardized protocol based on the recommendations of the ase . measurements of left ventricular ejection fraction ( lvef ) were performed using the modified biplane simpson s rule as a mean of three cardiac cycles . in patients with atrial fibrillation , the average value was obtained from six cardiac cycles . left ventricular diastolic function was evaluated by measuring mitral valve and pulmonary venous flow doppler parameters ; the mitral flow was recorded in basal condition and during valsalva manoeuvre , according to the standard criteria . the following echocardiographic parameters were evaluated : lvef , mitral inflow [ e wave velocity , a wave velocity , e / a ,  e / a ( changes from basal to valsalva manoeuvre ) , e wave deceleration time ( dt ) , a wave duration ( adur ) ] , pulmonary venous flow [ ( systolic velocity ( s ) , diastolic velocity ( d ) , a reverse wave duration ( ardur ) ] . diastolic function was classified , according to the progression of dysfunction , as follows : normal ( 0.75<e / a < 1.5 , dt>140 msec , e / a<0.5 during valsalva manoeuvre , sd , ardur < adur ) ; mild ( e / a0.75 , dt>140 msec , e / a < 0.5 , s > d , ardur < adur ) ; moderate ( 0.75 < e / a<1.5 , dt>140 ms , e / a0.5 , s < d or ardur > adur+30 ms ) and severe dysfunction ( e / a>1.5 , dt<140 ms , e / a0.5 , s < d or ardur > adur+30 ms ) . participants were required to have at least two concordant doppler criteria to be classified and patients with atrial fibrillation were excluded from evaluation of diastolic dysfunction . the study was approved by the local research ethic committees and all patients gave a written informed consent . all analyses were performed by using spss for windows ( version 12.0.1 , chicago ill ) . continuous variables are expressed as mean  sd or as median and 25 through 75 interquartiles when appropriate . the association between age and presence of ms was evaluated using nonparametric mann - whitney u test . stepwise logistic regression analysis was used to determine the association between ms and left ventricular systolic and diastolic dysfunction adjusting for age and gender . total of 6422 consecutive patients ( median age 59 years , interquartiles range : 48 - 68 ; men 3364 ) referred for a routine transthoracic examination to 75 national echocardiographic laboratories , were enrolled in the study . all laboratories were selected according to the competence level of the operators , which is level 3 in agreement with the american society of echocardiography ( ase ) requirements . detailed history of all the patients were taken , with focus on cardiovascular risk factors . exclusion criteria were : dyspnoea , valvular heart disease at least of moderate degree , previous valvular heart surgery , coronary artery by - pass surgery within the previous six months . in this study , we adopted the main definition of ms in accordance with the american heart association ( aha)/national heart , lung , and blood institute ( nhlbi ) scientific statements . we diagnosed ms with the presence of at least three of the following : hypertension , dyslipidemia , glucose intolerance and obesity with cutoff points consistent with the national cholesterol education program s adult treatment panel iii ( atp iii ) report , modified with body mass index ( bmi ) in place of waist circumference . hypertension was defined as systolic bp  140 mm hg , diastolic bp  90 mm hg , or self - reported antihypertensive medication use during the 2-week period before the clinical examination . dyslipidemia was defined as a low hdl cholesterol level ( < 40 mg / dl in men and < 50 mg / dl in women ) or as an elevated triglyceride level (  150 mg / dl ) . glucose intolerance was defined by the presence of diabetes ( self - reported physician diagnosis of diabetes , use of insulin or oral hypoglycemic medication , or fasting glucose level  126 mg / dl ) or impaired fasting glucose ( fasting glucose level  110 mg / dl ) according to american diabetes association criteria . subjects having three or more of the above mentioned criteria were classified as having ms . consistently with other major studies , we used bmi because we could not obtain waist circumference measurements for the entire study sample . the waist circumference criteria used in the atp iii definition were replaced with cutoff points for bmi ( 28.8 kg / m for men and 26.7 kg / m for women ) , as in previous studies . all patients underwent physical examination , 12-lead electrocardiography , and a complete transthoracic echocardiographic examination , according to the standardized protocol based on the recommendations of the ase . measurements of left ventricular ejection fraction ( lvef ) were performed using the modified biplane simpson s rule as a mean of three cardiac cycles . in patients with atrial fibrillation , the average value was obtained from six cardiac cycles . left ventricular diastolic function was evaluated by measuring mitral valve and pulmonary venous flow doppler parameters ; the mitral flow was recorded in basal condition and during valsalva manoeuvre , according to the standard criteria . the following echocardiographic parameters were evaluated : lvef , mitral inflow [ e wave velocity , a wave velocity , e / a ,  e / a ( changes from basal to valsalva manoeuvre ) , e wave deceleration time ( dt ) , a wave duration ( adur ) ] , pulmonary venous flow [ ( systolic velocity ( s ) , diastolic velocity ( d ) , a reverse wave duration ( ardur ) ] . diastolic function was classified , according to the progression of dysfunction , as follows : normal ( 0.75<e / a < 1.5 , dt>140 msec , e / a<0.5 during valsalva manoeuvre , sd , ardur < adur ) ; mild ( e / a0.75 , dt>140 msec , e / a < 0.5 , s > d , ardur < adur ) ; moderate ( 0.75 < e / a<1.5 , dt>140 ms , e / a0.5 , s < d or ardur > adur+30 ms ) and severe dysfunction ( e / a>1.5 , dt<140 ms , e / a0.5 , s < d or ardur > adur+30 ms ) . participants were required to have at least two concordant doppler criteria to be classified and patients with atrial fibrillation were excluded from evaluation of diastolic dysfunction . the study was approved by the local research ethic committees and all patients gave a written informed consent . all analyses were performed by using spss for windows ( version 12.0.1 , chicago ill ) . continuous variables are expressed as mean  sd or as median and 25 through 75 interquartiles when appropriate . the association between age and presence of ms was evaluated using nonparametric mann - whitney u test . stepwise logistic regression analysis was used to determine the association between ms and left ventricular systolic and diastolic dysfunction adjusting for age and gender . a total number of 6422 patients were eligible for the study . clinical characteristics of patients are shown in table 1 . patients were divided according to the absence or presence of ms into group a and group b [ table 2 ] . prevalence of ms was higher in man ( 9.1% ) than in women ( 8.5% ) , but not statistically significant ( p = 0.37 ) . study population characteristics group a = no metabolic syndrome ; group b = metabolic syndrome risk factors and ms prevalence left ventricular systolic function was evaluated in 6175 patients ( 96.2% ) ; in the remaining 247 patients ( 3.8% ) lvef was not calculated because of poor acoustic window . in the group of patients with ms ( group b ) , the prevalence of systolic dysfunction was significantly higher than in patients without ms ( group a ) , 12.5% vs 10.8% ( rr 1.57 ; ci 95% 1.2 - 2.0 ; p < 0.001 ) [ table 3 ] . systolic left ventricular dysfunction ( lvd ) in the two groups diastolic function was evaluated in 3936 patients ( 61.3% ) . the overall prevalence of diastolic lvd was 33.3% ( n = 1187 ) and was significantly higher in patients with ms , 45.7% vs 33.3% ( rr 1.68 ; ci 95% 1.3 - 2.0 ; p < 0.001 ) [ table 4 ] . diastolic left ventricular dysfunction ( lvd ) in the two groups moreover , logistic regression analysis showed that after adjustment for age and gender , ms was an independent predictor of both systolic and diastolic lvd [ tables 5 and 6 ] . in our study , we sought to determine if ms is associated with lvs and/or diastolic dysfunction in patients without symptoms for hf . in previous studies , we demonstrated that echocardiography can detect preclinical functional or structural myocardial abnormalities in asymptomatic subjects with two or more cvrs and without electrocardiogram abnormalities , and can improve the prognostic impact in comparison to other settings ( clinical , ecg ) . in this survey , asymptomatic patients having diagnosed for ms , were presented with significantly higher prevalence of systolic than patients with only one or two risk factors . more importantly , after adjustment for age and gender , ms proved to be a strong independent predictor of early lv systolic and diastolic dysfunction in this subset of patients . our results are consistent with other data available in literature , suggesting that ms leads to an higher risk of ventricular dysfunction involving the myocardium in early stages , before clinical signs of hf . individual ms markers are inferior to ms in identifying subtle cardiac dysfunction , emphasizing the importance of synergistic effect of these clinical conditions in identifying organ damage . particularly , among ms criteria , the coexistence of ms and type 2 diabetes exhibits the highest risk for biventricular dysfunction , requiring more aggressive therapeutic strategies to prevent hf . furthermore , the number of coexisting characteristics of metabolic syndrome ( arterial hypertension , central obesity , hyperglycemia and hypertriglyceridemia ) can strongly influence not only the presence , but also the degree of diastolic dysfunction . it has also been demonstrated that the impact of ms on lv remodeling and diastolic lvd is significantly influenced by gender , since the effects of ms on preclinical lvd were found to be more pronounced in women . however , these data were not confirmed in our study , in which no statistically significant differences were found between sex categories . in a community - based sample of middle - aged men , metabolic syndrome proved to be a significant predictor of hf , independent of established risk factors for hf , during two decades of moreover , data from a large trial on 9306 participants with impaired glucose tolerance and at least one or more cvr , reveal that traditional risk factors and novel indices of central adiposity and increased urinary albumin - creatinine are good predictors of incident hospitalization for hf . this implies that ms provides important risk information beyond that of established risk factors for hf . previous data supported the role of insulin resistance , as an important risk factor for the development of hypertension , atherosclerotic heart disease , left ventricular hypertrophy and hf , reflecting that a disturbance of glucose metabolism may potentially worsen metabolic efficiency of both skeletal muscle and cardiac muscle . some authors proposed that insulin resistance might be promoted by a sympathetic nervous system over activity , characterizing chronic hf and that this neurohormonal disregulation could be potentiated by obesity and ms . recently , it has been pointed out that superobesity is associated with insulin resistance , with a worse impact on cardiac remodeling and lv diastolic function than morbid obesity . consistently with an early myocardial damage , metabolic syndrome was recently found to be associated with decreased mechanical properties of the myocardium , particularly of sub - endocardial fibers , as demonstrated by an impairment of longitudinal myocardial diastolic and systolic functions , but preserved circumferential functions and twist mechanics . however , our study is the first large national multicenter study providing a real prevalence of asymptomatic lvd in a population with cvr and no symptoms for hf . limitation of this study is the selection of a sample of patients not representative of entire population , but a selected population with more prone to cvr . another limitation is that we used bmi rather than waist circumference to define metabolic syndrome . however , this parameter has been accepted by other major studies , in which a close correlation was found between bmi and waist circumference . moreover , being a national multicenter study , involving more than 75 centers , our protocol did not include tissue doppler imaging ( tdi ) or 2-dimensional ( 2d ) strain for longitudinal function and myocardial deformation evaluations , as they are not easily available in all echolabs within the territory . these data might have revealed an early left ventricular dysfunction also in patients with normal ef , unmasking the earliest stages of systolic lvd . limitation of this study is the selection of a sample of patients not representative of entire population , but a selected population with more prone to cvr . another limitation is that we used bmi rather than waist circumference to define metabolic syndrome . however , this parameter has been accepted by other major studies , in which a close correlation was found between bmi and waist circumference . moreover , being a national multicenter study , involving more than 75 centers , our protocol did not include tissue doppler imaging ( tdi ) or 2-dimensional ( 2d ) strain for longitudinal function and myocardial deformation evaluations , as they are not easily available in all echolabs within the territory . these data might have revealed an early left ventricular dysfunction also in patients with normal ef , unmasking the earliest stages of systolic lvd . our data show that in a large sample of asymptomatic patients , the presence of ms is an independent predictive risk factor for asymptomatic systolic and diastolic lvd . echocardiographic examination is a useful tool to detect left ventricular alterations in high risk patients , and may help to identify subset of patients prone to develop overt hf . the presence of these alterations may help to introduce lifestyle changes aimed to reducing single risk factors , or lead to establish a prompt pharmacological treatment to prevent future cardiovascular events and/or the progression to symptomatic congestive hf . considering the epidemiologic implication of the disease , patients who are at risk for ms , should be screened aggressively for cardio - vascular parameters with the aim of reducing morbidity and mortality , improving quality of life , and also reducing the financial burden .
context : metabolic syndrome ( ms ) is a cluster of interrelated common clinical disorders , including obesity , insulin resistance , glucose intolerance , hypertension and dyslipidemia , associated with a greater risk of atherosclerotic cardiovascular disease than any of its individual components . 
 although ms is associated with increased cardiovascular risk ( cvr ) , its relationship with heart failure ( hf ) and left ventricular ( lv ) dysfunction is not fully understood.aims:we sought to determine whether ms is associated to lv systolic and diastolic dysfunction in a sample of patients with ms and no symptoms for hf.subjects and methods : we enrolled 6422 consecutive asymptomatic patients admitted to echo - lab for a routine echocardiogram . 
 we calculated lv systolic and diastolic function , by simpson biplane method and validated doppler parameters , respectively . 
 ms was diagnosed if three or more cvr factors were found.results:lv systolic function was evaluated in 6175 patients ( 96.2% ) . in the group of patients without ms ( n = 5630 ) , 
 the prevalence of systolic dysfunction was 10.8% ( n = 607 ) while in the group of patients with ms ( n = 545 ) it was 12.5% ( n = 87 ) , ( rr1.57 ; ci 95% 1.2 - 2.0 ; p < 0.001 ) . 
 diastolic function was evaluated in 3936 patients ( 61.3% ) . in the group of patients without ms ( n = 3566 ) 
 the prevalence of diastolic dysfunction was 33.3% ( n = 1187 ) , while in patients with ms ( n = 370 ) it was 45.7% ( n = 169 ) , ( rr1.68 ; ci95% 1.3 - 2.0 ; p < 0.001 ) . 
 after adjustment for age and gender , ms proved to be an independent predictor of lv systolic and diastolic dysfunction.conclusions:our data show that asymptomatic lv systolic and diastolic dysfunction , is correlated with ms and demonstrate that echocardiography is a useful tool to detect patients at high risk for hf . 
 echocardiography in asymptomatic patients with ms may lead to a therapy initiation at early stages to prevent future cardiovascular events and hf .