pulmonary arterial hypertension ( pah ) is a progressive disease that can cause right ventricular ( rv ) dilatation and dysfunction as a result of increased pulmonary vascular resistance ( pvr ) and pulmonary arterial ( pa ) pressure.1)2 ) echocardiographic evidence of rv systolic dysfunction and clinical features of right - sided heart failure have been regarded as the main determinants of morbidity and mortality in patients with pah.3)4)5 ) despite the obvious clinical importance of assessing rv systolic function , the estimation of rv function can be challenging.6)7 ) because of their invasiveness and/or high - cost , right heart catheterization ( rhc ) and cardiac magnetic resonance imaging ( cmr ) are impractical for frequent serial assessment . although transthoracic 2-dimensional echocardiography ( 2de ) provides important information about rv anatomy , function and hemodynamic status , the complex geometry of the rv makes accurate assessment by conventional 2de difficult.8 ) moreover , conventional 2de measures including velocity and displacement based analyses can be affected by translational motion of the heart and respiratory variation.9 ) two - dimensional strain echocardiography has been introduced to assess regional and global rv function in various disease categories including pah.6)10)11)12 ) because longitudinal shortening contributes to overall rv systolic function , rv longitudinal strain ( rvls ) assessed by strain echocardiography can give direct information about regional and global rv mechanics . however , there are relatively small numbers of validation data in rv strain measurement . thus , we compared rvls with functional capacity and invasive hemodynamic data by rhc in patients with primary pah . we retrospectively studied consecutive adult patients ( > 18 years of age ) with world health organization ( who ) group 1 pah evaluated from february 2000 to december 2007 in the pah clinic of cleveland clinic . all patients fulfilled the contemporary diagnostic criteria,13 ) and they had regular outpatient follow - ups in this institution . patients with left ventricular ( lv ) systolic dysfunction , significant valvular heart disease , chronic thromboembolic disease , and pulmonary parenchymal diseases were excluded in this study . we included and analyzed echocardiographic data without change of medication during the time interval between echocardiography and rhc . patients without baseline echocardiographic examination or rhc in this institution , with poor echocardiographic images unable to analyze , atrial fibrillation , or medication change during time interval of two examinations were excluded . conventional 2de examinations were performed according to the guidelines and standard recommendations of the american society of echocardiography and were recorded digitally.14 ) in our institution , all echocardiographic images are stored digitally into echocardiographic database with digital imaging and communications in medicine standard format . echocardiographic images were reviewed by sonographers unaware of the clinical , laboratory , and hemodynamic information . rv fractional area change ( rvfac ) was calculated from the apical 4-chamber view using the percentage change in areas of the end - diastolic and end - systolic areas of the rv . the tricuspid annular plane systolic excursion ( tapse ) was recorded with m - mode echocardiography parallel to the lateral rv wall and across the tricuspid annular plane and measured as the distance of systolic movement of the rv annulus in the longitudinal direction.8 ) rv tei index was defined as the ratio of isovolumic relaxation time ( ivrt ) and isovolumic contraction time ( ivct ) divided by ejection time ( et ) of rv.8 ) rv free wall thickness was measured using m mode from the subcostal view at the peak of the r wave at the level of the tricuspid valve chordae tendineae . rv tei index was defined as the ratio of ivrt and ivct divided by et of rv.8 ) pa systolic pressure was estimated from the maximal continuous - wave doppler velocity of the tricuspid regurgitation ( tr ) jet imaged from multiple planes plus estimated central venous pressure calculated by the diameter of inferior vena cava and distensibility.8 ) an average of three measurements was used for all analyses . rv strain and strain rate were analyzed off - line with velocity vector imaging ( vvi ) software ( axius , siemens medical solutions , mountain view , ca , usa ) . after manual tracing of the endocardial border of the rv ( about 10 to 16 points ) over one frame , the endocardial borders were automatically tracked throughout the cardiac cycle . myocardial velocity is derived as the ratio between frame - to - frame displacement of the speckles and the time interval.12 ) global longitudinal strain and time - to peak strain were calculated . negative strain values indicate tissue shortening and a smaller value ( that is , higher absolute value ) indicates better rv systolic function . global longitudinal strain of rv ( rvlsglobal ) was calculated by the average of six segmental values of the lateral wall and interventricular septum . global longitudinal strain of rv free wall ( rvlsfw ) was measured by the averages of three segmental values ( base , mid and apex ) of the lateral wall . hemodynamic data included the pa systolic pressure ( spap ) , mean pa pressure ( mpap ) , pulmonary capillary wedge pressure ( pcwp ) , right atrium and rv pressures , and cardiac output . pvr was calculated using the formula ( mpap - pcwp)/cardiac output and reported in wood units . a 6-minute walking distance was performed according to the american thoracic society protocol.15 ) total distance walked , expressed in meters , was recorded . brain natriuretic peptide ( bnp ) was measured by triage immunoassay reagents ( biosite , san diego , ca , usa ) formatted for beckman coulter instrumentation ( brea , ca , usa ) . longitudinal strain measurements for each patient were performed offline in a blinded manner by two independent observers . each observer performed two independent measurements of regional and global rv strain values with vvi on same echocardiographic images in a randomly selected 10 patients . the data were analyzed using spss version 20.0 ( spss inc . , chicago , il , usa ) and medcalc version 12.4 ( medcalc software , mariakerke , belgium ) . linear regression analysis was performed to evaluate the relationship between rvls and other functional or invasive hemodynamic variables . a paired student t test was applied to evaluate the difference of basal and follow - up values . in the variables without normal distribution , wilcoxon signed rank test was used to evaluate the difference . to assess the overall differences on rvlsglobal between groups without versus with change of treatment ( i.e. treatment initiation or intensification ) , applied a linear mixed effects model with unstructured covariance for random effects was . effects of groups were tested as a factor , time after initial echocardiographic assessment as a covariate , as well as timegroup interactions . variability was tested with 2-way analysis of variance with calculation of intra- and inter - observer standard error or measurement ( semintra and seminter ) . semintra expresses the random error by a single observe , while seminter is an indicator of the mean variation between different observers.16 ) all tests were two - sided and p value<0.05 was considered statistically significant . we retrospectively studied consecutive adult patients ( > 18 years of age ) with world health organization ( who ) group 1 pah evaluated from february 2000 to december 2007 in the pah clinic of cleveland clinic . all patients fulfilled the contemporary diagnostic criteria,13 ) and they had regular outpatient follow - ups in this institution . patients with left ventricular ( lv ) systolic dysfunction , significant valvular heart disease , chronic thromboembolic disease , and pulmonary parenchymal diseases were excluded in this study . we included and analyzed echocardiographic data without change of medication during the time interval between echocardiography and rhc . patients without baseline echocardiographic examination or rhc in this institution , with poor echocardiographic images unable to analyze , atrial fibrillation , or medication change during time interval of two examinations were excluded . conventional 2de examinations were performed according to the guidelines and standard recommendations of the american society of echocardiography and were recorded digitally.14 ) in our institution , all echocardiographic images are stored digitally into echocardiographic database with digital imaging and communications in medicine standard format . echocardiographic images were reviewed by sonographers unaware of the clinical , laboratory , and hemodynamic information . rv fractional area change ( rvfac ) was calculated from the apical 4-chamber view using the percentage change in areas of the end - diastolic and end - systolic areas of the rv . the tricuspid annular plane systolic excursion ( tapse ) was recorded with m - mode echocardiography parallel to the lateral rv wall and across the tricuspid annular plane and measured as the distance of systolic movement of the rv annulus in the longitudinal direction.8 ) rv tei index was defined as the ratio of isovolumic relaxation time ( ivrt ) and isovolumic contraction time ( ivct ) divided by ejection time ( et ) of rv.8 ) rv free wall thickness was measured using m mode from the subcostal view at the peak of the r wave at the level of the tricuspid valve chordae tendineae . rv tei index was defined as the ratio of ivrt and ivct divided by et of rv.8 ) pa systolic pressure was estimated from the maximal continuous - wave doppler velocity of the tricuspid regurgitation ( tr ) jet imaged from multiple planes plus estimated central venous pressure calculated by the diameter of inferior vena cava and distensibility.8 ) an average of three measurements was used for all analyses . rv strain and strain rate were analyzed off - line with velocity vector imaging ( vvi ) software ( axius , siemens medical solutions , mountain view , ca , usa ) . after manual tracing of the endocardial border of the rv ( about 10 to 16 points ) over one frame , the endocardial borders were automatically tracked throughout the cardiac cycle . myocardial velocity is derived as the ratio between frame - to - frame displacement of the speckles and the time interval.12 ) global longitudinal strain and time - to peak strain were calculated . negative strain values indicate tissue shortening and a smaller value ( that is , higher absolute value ) indicates better rv systolic function . global longitudinal strain of rv ( rvlsglobal ) was calculated by the average of six segmental values of the lateral wall and interventricular septum . global longitudinal strain of rv free wall ( rvlsfw ) was measured by the averages of three segmental values ( base , mid and apex ) of the lateral wall . hemodynamic data included the pa systolic pressure ( spap ) , mean pa pressure ( mpap ) , pulmonary capillary wedge pressure ( pcwp ) , right atrium and rv pressures , and cardiac output . pvr was calculated using the formula ( mpap - pcwp)/cardiac output and reported in wood units . a 6-minute walking distance was performed according to the american thoracic society protocol.15 ) total distance walked , expressed in meters , was recorded . brain natriuretic peptide ( bnp ) was measured by triage immunoassay reagents ( biosite , san diego , ca , usa ) formatted for beckman coulter instrumentation ( brea , ca , usa ) . longitudinal strain measurements for each patient were performed offline in a blinded manner by two independent observers . each observer performed two independent measurements of regional and global rv strain values with vvi on same echocardiographic images in a randomly selected 10 patients . the data were analyzed using spss version 20.0 ( spss inc . , chicago , il , usa ) and medcalc version 12.4 ( medcalc software , mariakerke , belgium ) . linear regression analysis was performed to evaluate the relationship between rvls and other functional or invasive hemodynamic variables . a paired student t test was applied to evaluate the difference of basal and follow - up values . in the variables without normal distribution , wilcoxon signed rank test was used to evaluate the difference . to assess the overall differences on rvlsglobal between groups without versus with change of treatment ( i.e. treatment initiation or intensification ) , applied a linear mixed effects model with unstructured covariance for random effects was . effects of groups were tested as a factor , time after initial echocardiographic assessment as a covariate , as well as timegroup interactions . variability was tested with 2-way analysis of variance with calculation of intra- and inter - observer standard error or measurement ( semintra and seminter ) . semintra expresses the random error by a single observe , while seminter is an indicator of the mean variation between different observers.16 ) all tests were two - sided and p value<0.05 was considered statistically significant . a total 34 patients ( 29 females , mean age 4513 years old ) with who group i pah { dana point group i : 26 idiopathic , 5 familial , and 3 associated with other diseases ( 2 with connective tissue disease and 1 with systemic to pulmonary shunt ) } were included in this study . their mean duration of disease was 2331 months ( range 0 - 94 months ) and the majority of patients were who functional class ii ( 29% ) and iii ( 62% ) . their mean time interval between echocardiography and rhc was 5 days ( range : 0 - 30 days ) . twenty patients had been diagnosed as pah in this institution and the remaining 16 patients were transferred from other hospitals . eight patients were taking a single vasodilator medication { 1 on a phosphodiesterase-5 inhibitor ( pde5i ) , 3 on an oral endothelin receptor antagonists ( era ) , and 4 on prostaglandins } and 8 patients were taking a combination of vasodilators ( 3 on era and prostaglandins , 3 on pde5i and prostaglandins , and 2 on pde5i , era , and prostaglandins ) . the baseline clinical , laboratory , echocardiographic , and hemodynamic data ( table 1 ) were typical for a pah population , with normal lv systolic function , elevated pa pressure , rv enlargement , and rv systolic dysfunction . in patients with advanced clinical symptoms ( nyha functional class iii / iv ) had significantly decreased rvlsglobal ( -17.16.1 vs. -11.43.1% , p=0.01 ) . rvlsfw showed lower in the patients with advanced symptoms without statistical significance ( -18.37.1 vs. -13.44.4% , p=0.08 , fig . rvlsglobal showed good correlations with 6-minute walking distance ( 6mwd , r=-0.54 , p<0.01 ) and logarithmic transformation of bnp concentration ( logbnp , r=0.65 , p<0.01 , fig . 2a and c ) . also , rvlsfw demonstrated significant correlations with 6mwd ( r=-0.57 , p<0.01 ) and logbnp ( r=0.65 , p<0.01 , fig . rvlsglobal had significant correlations with hemodynamic parameters including mpap ( r=0.35 , p<0.05 ) , cardiac index ( r=0.50 , p<0.01 , and pvr ( r=-0.45 , p=0.01 , fig . rvlsfw showed similar correlation with cardiac index ( r=-0.47 , p<0.01 ) and pvr ( r=0.45 , p=0.01 ) . however , it did not have a significant correlation with mpap ( r=0.31 , p=0.08 , fig . follow - up rhc data were available in 25 patients with median time interval of two rhcs was 33 months ( inter - quartile range=21 - 57 months ) . during the period , they were treated with additional specific pulmonary vasodilator therapy ( 19 with prostaglandin therapy , 3 with pde5i , 1 with era , and 2 with combination of era and pde5i ) . the follow - up clinical , echocardiographic and hemodynamic data are listed in table 2 . with specific pulmonary vasodilator treatment , clinical symptoms were improved , 6mwds were increased and bnp levels were decreased . follow - up rvlsglobal value also showed significant correlation with follow - up 6mwd ( r=-0.44 , p=0.04 ) whereas rvlsfw showed insignificant correlation ( r=-0.40 , p=0.06 ) . as baseline logbnp , follow - up logbnp revealed significant correlations with rvlsglobal ( r=0.75 , p<0.01 ) and rvlsfw ( r=0.68 , p<0.01 ) . there were significant correlations between the change of mpap and rvlsglobal ( r=0.45 , p<0.01 ) and rvlsfw ( r=0.43 , p<0.01 , fig . the change of pvr also had significant correlations with change of rvlsglobal ( r=0.40 , p=0.01 ) and rvlsfw ( r=0.31 , p<0.05 , fig . however , 5 patients had a worsening of 6mwd . in patients with worsening of 6mwd , rvlsglobal showed no significant change ( from -13.53.8% to -13.94.7% , p=0.86 ) . in patients with improvement of 6mwd , rvlsglobal improved from -12.75.8% to -16.05.2% ( p=0.03 ) . interestingly , the rvfac ( a " conventional " marker of rv function ) was significantly changed in both patient groups ( in patients with worsening of 6mwd : from 204% to 264% , p=0.02 ; in patients with improvement in 6mwd : from 217% to 299% , p<0.01 ) . in our cohort , all patients underwent echocardiographic follow - up studies early ( within 1 to 6 months , median 95 days ) and late ( > 1 year , median 772 days ) . there were 6 patients without change of treatment after initial echocardiography and 28 patients with either treatment initiation or intensification ( i.e. , increase in dose or addition of another agent ) . 5 . there was an improvement of rvlsglobal during follow - up in patients with change of medication ( p=0.03 for the difference in slopes ) . interestingly , while rvlsglobal was overall higher in the group without the change of medication ( p=0.04 ) , there was no additional change during follow - up . a total 34 patients ( 29 females , mean age 4513 years old ) with who group i pah { dana point group i : 26 idiopathic , 5 familial , and 3 associated with other diseases ( 2 with connective tissue disease and 1 with systemic to pulmonary shunt ) } were included in this study . their mean duration of disease was 2331 months ( range 0 - 94 months ) and the majority of patients were who functional class ii ( 29% ) and iii ( 62% ) . their mean time interval between echocardiography and rhc was 5 days ( range : 0 - 30 days ) . twenty patients had been diagnosed as pah in this institution and the remaining 16 patients were transferred from other hospitals . eight patients were taking a single vasodilator medication { 1 on a phosphodiesterase-5 inhibitor ( pde5i ) , 3 on an oral endothelin receptor antagonists ( era ) , and 4 on prostaglandins } and 8 patients were taking a combination of vasodilators ( 3 on era and prostaglandins , 3 on pde5i and prostaglandins , and 2 on pde5i , era , and prostaglandins ) . the baseline clinical , laboratory , echocardiographic , and hemodynamic data ( table 1 ) were typical for a pah population , with normal lv systolic function , elevated pa pressure , rv enlargement , and rv systolic dysfunction . rvlsglobal was -13.35.0% and rvlsfw was -15.15.8% . in patients with advanced clinical symptoms ( nyha functional class iii / iv ) had significantly decreased rvlsglobal ( -17.16.1 vs. -11.43.1% , p=0.01 ) . rvlsfw showed lower in the patients with advanced symptoms without statistical significance ( -18.37.1 vs. -13.44.4% , p=0.08 , fig . rvlsglobal showed good correlations with 6-minute walking distance ( 6mwd , r=-0.54 , p<0.01 ) and logarithmic transformation of bnp concentration ( logbnp , r=0.65 , p<0.01 , fig . 2a and c ) . also , rvlsfw demonstrated significant correlations with 6mwd ( r=-0.57 , p<0.01 ) and logbnp ( r=0.65 , p<0.01 , fig . rvlsglobal had significant correlations with hemodynamic parameters including mpap ( r=0.35 , p<0.05 ) , cardiac index ( r=0.50 , p<0.01 , and pvr ( r=-0.45 , p=0.01 , fig . rvlsfw showed similar correlation with cardiac index ( r=-0.47 , p<0.01 ) and pvr ( r=0.45 , p=0.01 ) . however , it did not have a significant correlation with mpap ( r=0.31 , p=0.08 , fig . follow - up rhc data were available in 25 patients with median time interval of two rhcs was 33 months ( inter - quartile range=21 - 57 months ) . during the period , they were treated with additional specific pulmonary vasodilator therapy ( 19 with prostaglandin therapy , 3 with pde5i , 1 with era , and 2 with combination of era and pde5i ) . the follow - up clinical , echocardiographic and hemodynamic data are listed in table 2 . with specific pulmonary vasodilator treatment , clinical symptoms were improved , 6mwds were increased and bnp levels were decreased . rv systolic function was improved , and mpap and pvr were decreased . follow - up rvlsglobal value also showed significant correlation with follow - up 6mwd ( r=-0.44 , p=0.04 ) whereas rvlsfw showed insignificant correlation ( r=-0.40 , p=0.06 ) . as baseline logbnp , follow - up logbnp revealed significant correlations with rvlsglobal ( r=0.75 , p<0.01 ) and rvlsfw ( r=0.68 , p<0.01 ) . there were significant correlations between the change of mpap and rvlsglobal ( r=0.45 , p<0.01 ) and rvlsfw ( r=0.43 , p<0.01 , fig . the change of pvr also had significant correlations with change of rvlsglobal ( r=0.40 , p=0.01 ) and rvlsfw ( r=0.31 , p<0.05 , fig . however , 5 patients had a worsening of 6mwd . in patients with worsening of 6mwd , rvlsglobal showed no significant change ( from -13.53.8% to -13.94.7% , p=0.86 ) . in patients with improvement of 6mwd , interestingly , the rvfac ( a " conventional " marker of rv function ) was significantly changed in both patient groups ( in patients with worsening of 6mwd : from 204% to 264% , p=0.02 ; in patients with improvement in 6mwd : from 217% to 299% , p<0.01 ) . in our cohort , all patients underwent echocardiographic follow - up studies early ( within 1 to 6 months , median 95 days ) and late ( > 1 year , median 772 days ) . there were 6 patients without change of treatment after initial echocardiography and 28 patients with either treatment initiation or intensification ( i.e. , increase in dose or addition of another agent ) . 5 . there was an improvement of rvlsglobal during follow - up in patients with change of medication ( p=0.03 for the difference in slopes ) . interestingly , while rvlsglobal was overall higher in the group without the change of medication ( p=0.04 ) , there was no additional change during follow - up . , echocardiographic follow - up data showed that changes in rvls reflect changes in treatment during follow - up . this is relevant since , to our knowledge , there are no studies documenting the changes in rvls during pulmonary hypertension treatment . these findings imply that , while single measurement of rvls is prognostically relevant , it may be also necessary to track changes in treatment to appreciate its impact , and improve prognostication . finally , when compared to previous studies,17)18 ) in this manuscript we correlate rvls with measured , rather than estimated , rvsp and pulmonary vascular resistance . this finding is also relevant since a recent study19 ) showed that echocardiographic estimation may not be always accurate . although rv systolic dysfunction is an important prognostic factor in pah patients , rv assessment can be challenging.20 ) rhc gives important pressure- and flow - derived parameters in the diagnosis and management of pah patients.21 ) however , frequent serial measurement is invasive and impractical.22 ) cmr is a useful imaging method providing morphological and functional information of the rv.23)24 ) however , it is expensive , time consuming , and not readily available in most institutions , and may not be performed in some patients . it provides several doppler - derived parameters about right heart hemodynamics and some parameters ; tapse or presence of pericardial effusion , are known as prognostic factors in pah patients.20 ) however , the assessment of rv function parameters by standard 2de often remains insufficient because of measurement variability intrinsic to the parameters measured.19 ) two - dimensional strain echocardiography is a new method providing relatively easy and angle - independent quantification of myocardial deformation on 2de images.12 ) because the predominant orientation of muscle fiber in the rv is in the longitudinal plane , longitudinal motion of rv is a major determinant of rv systolic function , especially in patients with pah.7 ) strain echocardiography can measure rvls , and rvls can give direct information about regional and global rv mechanics . rv dysfunction is a well - known factor of functional impairment in pah patients.25 ) presently , patients with advanced symptoms had more decreased rvls . our result is similar to the previously reported studies showing pah patients with worse rv longitudinal peak systolic strain had worse functional class and lower rv systolic function.12)26 ) patients with poor exercise capacity ( 6mwd<332 m ) have poor prognosis.20)27 ) rvls significantly correlated with functional capacity assessed by 6mwd at baseline and follow - up in this study . after adjustment of age , gender , body mass index , cardiac index and mpap , rvlsglobal ( standardized =-0.63 , p<0.01 ) and rvlsrvfw ( standardized =-0.59 , p<0.01 ) showed significant association with baseline 6mwd . increased pvr , as consequences of pathological changes in the pulmonary arteries , results in rv pressure overload and rv systolic dysfunction in pah.25 ) chronic rv pressure overload directly affect rv longitudinal systolic function and result in impairment of rvls.17 ) pirat et al.12 ) reported significantly impaired global and regional rv systolic function in 57 patients with pah compared with age - matched normal controls . sachdev et al.6 ) documented significantly decreased rv longitudinal peak systolic strain of rv free wall ( -155% ) in a cohort of 80 pah patients . they showed that patients with impaired rv free wall strain ( > -12.5% ) had higher mpap and pvr . in our study , mean rvlsglobal was -13.25.0% and rvlsfw was -15.15.8% , and these values are similarly decreased as in the study of sachdev et al.6 ) we showed significant correlations of baseline rvls with functional and hemodynamic parameters . recent development of pharmaceutical therapies has resulted in improved hemodynamics , exercise capacity , and prognosis in pah patients.28 ) the effect of specific pulmonary vasodilator therapy on rvls and their relationship with invasive hemodynamic parameters was also investigated . moreover , there are several reports regarding how impaired rvls can be used as a prognostic markers in pah patients.6)18)26 ) these results suggest that rvls can be a useful non - invasive indicator in the serial assessment of rv systolic function in pah patients . in this retrospective and observational study , major limitations include the relatively small numbers of pah patients and the number of pah patients who did not have repeat right heart catheterization . bias may have been introduced from patient selection . this result suggests that the assessment of rvls may be useful to track clinical changes in pah patients . we analyzed rvls with stored images , and the analysis may have been affected by image quality and echocardiographic machines . secondly , we used a vendor - independent platform to measure rvls with echocardiographic images studied by different echocardiographic machines . however , using a vendor - independent platform from different echocardiographic machines can be an option in the comparison of rvls in serial echocardiographic examinations , especially in the assessment of treatment effects . echocardiographic parameters and cardiac catheterization were not performed simultaneously . the decision for a second catheterization nonetheless , a prospective study with large numbers of patients using the same echocardiographic machine will be needed to confirm the correlations and the clinical impact of this measurement . rvls calculated by strain echocardiography correlates with functional capacity and invasive hemodynamic parameters in patients with pah . the increase of rvls corresponds with the decrease of mpap and pvr with specific pulmonary vasodilator therapy . decrease of mpap and pvr as a result of treatment was associated with improvement of rvls . in this retrospective and observational study , major limitations include the relatively small numbers of pah patients and the number of pah patients who did not have repeat right heart catheterization . this result suggests that the assessment of rvls may be useful to track clinical changes in pah patients . we analyzed rvls with stored images , and the analysis may have been affected by image quality and echocardiographic machines . secondly , we used a vendor - independent platform to measure rvls with echocardiographic images studied by different echocardiographic machines . however , using a vendor - independent platform from different echocardiographic machines can be an option in the comparison of rvls in serial echocardiographic examinations , especially in the assessment of treatment effects . echocardiographic parameters and cardiac catheterization were not performed simultaneously . the decision for a second catheterization nonetheless , a prospective study with large numbers of patients using the same echocardiographic machine will be needed to confirm the correlations and the clinical impact of this measurement . rvls calculated by strain echocardiography correlates with functional capacity and invasive hemodynamic parameters in patients with pah . the increase of rvls corresponds with the decrease of mpap and pvr with specific pulmonary vasodilator therapy . decrease of mpap and pvr as a result of treatment was associated with improvement of rvls .
background and objectivesright ventricular longitudinal strain ( rvls ) is a new parameter of rv function . 
 we evaluated the relationship of rvls by speckle - tracking echocardiography with functional and invasive parameters in pulmonary arterial hypertension ( pah ) patients.subjects and methodsthirty four patients with world health organization group 1 pah ( 29 females , mean age 4513 years old ) . 
 rvls were analyzed with velocity vector imaging.resultspatients with advanced symptoms { new york heart association ( nyha ) functional class iii / iv } had impaired rvls in global rv ( rvlsglobal , -175 vs. -123% , p<0.01 ) and rv free wall ( rvlsfw , -195 vs. -144% , p<0.01 to nyha class i / ii ) . 
 baseline rvlsglobal and rvlsfw showed significant correlation with 6-minute walking distance ( r=-0.54 and r=-0.57 , p<0.01 respectively ) and logarithmic transformation of brain natriuretic peptide concentration ( r=0.65 and r=0.65 , p<0.01 , respectively ) . 
 these revealed significant correlations with cardiac index ( r=-0.50 and r=-0.47 , p<0.01 , respectively ) and pulmonary vascular resistance ( pvr , r=0.45 and r=0.45 , p=0.01 , respectively ) . during a median follow - up of 33 months , 25 patients ( 74% ) had follow - up examinations . 
 mean pulmonary arterial pressure ( mpap , 5413 to 4616 mmhg , p=0.03 ) and pvr ( 115 to 62 wood units , p<0.01 ) were significantly decreased with pulmonary vasodilator treatment . 
 rvlsglobal ( -125 to -165% , p<0.01 ) and rvlsfw ( -145 to -185% , p<0.01 ) were significantly improved . 
 the decrease of mpap was significantly correlated with improvement of rvlsglobal ( r=0.45 , p<0.01 ) and rvlsfw ( r=0.43 , p<0.01 ) . 
 the pvr change demonstrated significant correlation with improvement of rvlsglobal ( r=0.40 , p<0.01).conclusionrvls correlates with functional and invasive hemodynamic parameters in pah patients . 
 decrease of mpap and pvr as a result of treatment was associated with improvement of rvls .