obesity is a major public health problem , with a prevalence of 10% to 20% in western europe . obesity is characterized by both a large increase in body weight and an increase in body fat exceeding standard measures . currently , obesity is classified on the basis of body mass index ( bmi ) , and patients with bmi > 30  kg / m are considered obese . a bmi > 30  kg / m has a negative impact on health and is associated with premature atherosclerosis , increased risk of myocardial infarction , and heart failure . severe obesity is associated with decreased survival , largely because of cardiovascular deaths [ 3 , 4 ] . most echocardiographic studies assessing left ventricular ( lv ) systolic function in obese patients used ejection phase indices like lv ejection fraction and lv fractional shortening . they reported normal or hyperdynamic lv systolic function and no or little differences in lean and obese subjects [ 5 , 6 ] . impaired lv systolic function in persons with obesity was only found in the presence of coexistent heart disease . more recent echocardiography technics like tissue - doppler and strain imaging have revealed evidence of subclinical lv systolic dysfunction in subjects with obesity , even in the presence of normal lv ejection phase indices [ 8 , 9 ] . alterations in cardiac function have also been shown to be reversible with weight reduction strategies [ 10 , 11 ] . weight loss after interventions like bariatric surgery and dietary weight reduction can be beneficial to cardiovascular structure and function and result in a decrease in cardiovascular risk and total mortality [ 1214 ] . the purpose of this study was to examine systolic left ventricular function and the effect of diet - induced weight loss in patients with severe obesity by transthoracic two - speckle - tracking echocardiography ( ste ) with lv strain imaging . the study was approved by the ethics committee of the state medical council of hessen , germany ( approval number ff 112/2015 ) . all patients were participants in the optifast-52 diet program ( nestl health science , frankfurt , germany ) , which ran for a total of 52 consecutive weeks . the specifics of the program included a fasting phase of 12 weeks with ingestion of food restricted to formula products with a high protein content . a subsequent transitional phase and a final stabilization phase aim to introduce the patients to a balanced diet . for the duration of the program , all patients received psychological , physiotherapeutic , medical , and nutritional care . inclusion criteria were as follows : age 18 and 65 years , bmi > 30 kg / m , secondary and accompanying conditions requiring treatment such as hypertension , hypercholesterolemia , diabetes mellitus , and illnesses of the locomotor system . all patients had made repeated ( at least three ) unsuccessful attempts to reduce weight . exclusion criteria were cardiac arrhythmia , recent myocardial infarction , severe ( malign ) general illnesses , pregnancy and nursing , or a documented eating disorder . total body composition and fat content was also measured using the dual energy x - ray absorptiometry ( dxa ) in week 1 and in week 12 . echocardiography was performed using a commercially available ultrasound machine ( vivid 7 , ge healthcare , horten , norway ) and a 3.5  mhz ( 3s - rs ) transducer . patients were examined in a resting , left - lateral position and , for specific parts of the examination , in end - expiration by an experienced examiner . all images were obtained from standard parasternal and apical position using 2d and m - mode echocardiographic techniques . lv ejection phase indices like lv ejection fraction and fractional shortening were calculated from parasternal m - mode measurements . two - dimensional ste analysis was performed offline using dedicated automated software ( echopac pc , version 6.0 , ge healthcare , horten , norway ) . from the apical and parasternal short - axis datasets , the software divided the lv into six segments and performed speckle - tracking analysis throughout one cardiac cycle . finally , the software automatically created the time - domain lv strain curves in six segments , from which end - systolic strain was calculated . global longitudinal peak systolic strain ( glps ) was defined as the averaged longitudinal strains at end - systole in 18 segments from three apical views . global radial strain ( grs ) was defined as averaged radial strain at end - systole in 18 segments from three levels of short - axis views . dxa is a common measurement of human body composition based on a three - compartment model . it divides the body into total body mineral , fat - free soft mass , and fat tissue mass . body composition was evaluated by dxa with the use of a hologic densitometer ( qdr discovery wi , hologic inc . , measurements were taken with the patient lying in the supine position on the scanning table . the results are expressed as mean  standard deviation ( sd ) for continuous variables . for the descriptive statistics , the arithmetic mean , sd , median , minimum and maximum , and first and third quartiles were calculated . for the comparison of two measurements at different times , statistical analyses were performed using a statistical software package ( bias for windows , version 11.0 ) . body weight decreased significantly from week 1 to week 12 of the weight loss program ( figure 2 ) . the number of patients with arterial hypertension defined as blood pressure > 140  mmhg systolic and > 90  mmhg diastolic decreased from 9 patients to 1 patient . mean systolic blood pressure was significantly reduced from 148  16 to 130  17  mmhg and diastolic blood pressure from 95  14 to 82  9  mmhg . the mean heart rate also decreased significantly from 94  16 to 82  9 beats per minute , respectively . total body fat mass decreased by 19% ( mean ) from 50.9  20.9  kg to 41.1  16.9  kg . changes in fat distribution resulting from the 12 week fasting phase are reported in table 2 . grading of the image quality before weight loss was good in 9 , moderate in 7 , and poor in 5 patients . after weight loss , image quality improved to good in 11 , moderate in 7 , and poor in 3 patients . lv ejection phase indices , lv ejection fraction and fractional shortening , were within normal range at baseline and remained unchanged after weight loss ( table 3 ) . glps at baseline was 18.7  3.2 in week 1 and 18.8  2.4 in week 12 ( figure 3 ) . no significant correlation was noted between glps and bmi ( r = 0.36 , p = ns ) . we found a weak but not significant correlation between percentage weight loss and increase in glps ( r = 0.39 , p = ns ) . also , no significant change in grs after weight loss was noted ( 41.1  22.0 versus 43.9  23.3 , p = 0.09 ) . the left atrial diameter ( anterior - posterior ) measured in the parasternal long - axis view weight reduction after 12 weeks of diet was associated with a decrease in left atrial size , but the difference was not significant ( table 3 ) . left atrial volume , lv wall thickness , and lv end - diastolic diameter were within normal range at baseline and remained unchanged after weight loss . variable findings have been reported with respect to systolic function in obese subjects , including preserved or mildly reduced left ventricular function . interestingly , these alterations have been shown to be reversible with weight reduction therapies [ 10 , 17 ] . lv ejection fraction appears to be clinically the most relevant parameter . however , lv ejection fraction has some limitations . the most important , it is not sensitive enough to detect subtle alterations in the contractile function and therefore not suitable for detecting subclinical myocardial damage . in some studies , tissue - doppler echocardiography has been able to show the presence of subclinical systolic contractile abnormalities , although the left ventricular ejection fraction remained within the normal range [ 8 , 9 , 1922 ] . two - dimensional ste is a new gray - scale based technique that provides angle - independent measurements of myocardial deformation and has the potential for quantitative assessment of systolic left ventricular function [ 18 , 23 ] . speckles are produced as a result of the scatter of the ultrasound beam by the tissue . by tracking frame by frame the displacement of the speckles during the cardiac cycle , strain , software automatically resolves the magnitude of myocardial deformation in different directions and generates strain . strain is the percentage change in the length of a myocardial segment during a cardiac cycle and has the unit % . in the present study , lv ejection phase indices , lv ejection fraction and fractional shortening , were normal at baseline and unchanged at follow - up . also , systolic left ventricular function quantified by glps and grs was normal . we found glps and grs values in a range comparable to values defined as normal in a large meta - analysis including 2,597 subjects from 24 studies . other studies in obese individuals without cardiac disease reported similar lv ejection fraction but worse systolic mechanics as assessed by glps when compared with nonobese controls [ 2527 ] . a recent study by leung et al . found a significant improvement in both systolic and diastolic myocardial function measured by longitudinal strain in obese patients with type 2 diabetes and weight loss 9 months after sleeve gastrectomy . a behavioural intervention program including dietary restrictions and exercise training in obese patients found an increase in strain measured by tissue - doppler myocardial imaging in patients with significant reduction of weight after 6 months . in contrast to other studies we could not find a significant increase in glps or grs after weight loss . this might be due to a shorter follow - up period , a lower rate of concomitant diseases , and different weight loss strategies [ 30 , 31 ] . in moderate - to - severe cases of obesity , increased cardiac output as a result of the high metabolic activity of excessive fat may lead to left atrial and ventricular dilation , increased lv wall stress , and compensatory ( eccentric ) lv hypertrophy [ 32 , 33 ] . in the present study , mean lv diameter and thickness of the lv wall were normal at baseline and remained unchanged after 12 weeks on the diet . an echocardiographic study in obese patients with a bmi of 50.0  1.4 who underwent bariatric surgery reported a decrease in lv dilatation and hypertrophy after a longer follow - up period of 13  4 months . other studies have also shown a decrease in lv mass and size one to three years after weight reduction interventions [ 7 , 35 , 36 ] . similar findings were reported in patients with obesity after gastric bypass surgery [ 36 , 37 ] . lifestyle and diet therapies have demonstrated some cardiovascular benefits . the data from a number of recent meta - analyses , however , suggests that bariatric operations result in larger benefits to cardiovascular risk parameters than other weight loss therapies . however , no randomized controlled trials currently exist comparing the effects of bariatric surgery with standardized nonsurgical treatments , specifically focusing on cardiovascular end points . the small number of the study groups limits interpretation of the results , in particular p values . we were unable to demonstrate cardiac changes due to obesity such as lv hypertrophy and enlargement or atrial dilatation as described by other authors . however , patients in our group were relatively young ( mean age 43 years ) in terms of the risk of other causes of structural cardiac abnormalities . glps measured by ste in order to determine systolic function is in part heart rate and blood pressure - dependent and is subject to change within any given patient . finally , when studying people with obesity , echocardiographic measurements may be error - prone or imprecise . in our study , obesity was not associated with systolic dysfunction measured by ste with strain imaging . dimensions of left atrial and ventricular structures were normal at baseline and not altered after weight loss . diet with successful weight reduction goes along with reduction in blood pressure and heart rate .