atrial fibrillation ( af ) is the most common arrhythmia in the general population and is associated with significant cardiovascular morbidity ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8) . left atrium ( la ) structural changes play a major role in the process of initiation and maintenance of the arrhythmia together , with fibrosis and myofibre disarray ( 1 , 2 , 9 ) . although la size appears to be a factor for af recurrence , it is , however , determined by many other factors such as age , cause and af duration ( 2 , 6 ) . la function modulates left ventricle ( lv ) filling through its three components : the reservoir phase during ventricular systole , conduit phase during early ventricular diastole and pump phase at end ventricular diastole ( 1 , 6 ) . in af , the reservoir and conduit functions are believed to be impaired and pump function is lost ( 6 , 7 ) . new markers of atrial structural remodelling and myocardial deformation properties , measured as strain and strain rate by two - dimensional speckle - tracking techniques , have recently been proposed ( 1 , 2 , 3 , 6 , 8 , 10 , 11 , 12 ) . these parameters have the advantage of being angle - independent ( 2 , 10 , 11 ) . several studies conducted in recent years found that patients with af have lower la strain values compared with healthy controls ( 2 , 3 , 5 , 7 , 8) . la wall fibrosis , as part of structural remodelling occurring in af , seems to be inversely related to la strain and strain rate ( 13 ) . these parameters of myocardial deformation could thus identify patients at increased risk of developing af and predict , in those with diagnosed arrhythmia , the success of therapeutic interventions ( 2 ) , one of which is external electrical cardioversion ( ecv ) , considered to be the most effective for restoring sinus rhythm ( sr ) ( 4 , 6 , 7 ) . this study aimed to ascertain whether atrial deformation parameters can : ( 1 ) identify individuals with higher thrombotic risk , defined as low laa velocities < 25cm / s or laa thrombus ; and ( 2 ) foresee unsuccessful ecv , in a population of patients with af and atrial flutter ( afl ) . one hundred and thirty - three consecutive patients with af or afl undergoing a first ecv between 2010 and 2014 at the hospital vall dhebron , barcelona , were retrospectively evaluated . transthoracic ( tte ) and transoesophageal echocardiography ( tee ) studies were conducted before cardioversion in all patients . exclusion criteria were presence of organic valvular disease ( n=15 ) , prosthetic valves ( n=2 ) , pericarditis or acute myocardial infarction ( n=3 ) , or a recent history of heart surgery or pacemaker implantation ( n=7 ) and without minimum requirements for lad analysis ( n=50 ) . demographics , medical history including the type of arrhythmia ( af or afl ) , duration of the arrhythmia episode classified as paroxysmal ( if it lasted less than 48h ) and as persistent ( lasting days or months ) and other co - morbidities ( hypertension , diabetes , history of stroke and body mass index ) are given in table 1 . table 1clinical and echocardiographic characteristics of patients.demographic characterizationco - morbiditiessexmale36 ( 64%)hypertension39 ( 69.6%)female20 ( 36%)diabetes14 ( 25%)age ( years)67 ( 5974)history of stroke2 ( 3.6%)body mass index ( kg / m)28.8 ( 25.431.6)arrhythmia characterizationtype of arrhythmiaatrial fibrillation39 ( 69.6%)atrial flutter17 ( 30.4%)heart rate ( hr ) during the exam ( beats per minute)100 ( 80125)duration of the episodeparoxysmal ( < 48 h)5 ( 8.9%)persistent ( days)42 ( 75%)persistent ( months)9 ( 16.1%)echocardiographic characterizationlvedd ( mm)49 ( 4555)lalamv ( ml)80 ( 65106)esd ( mm)37 ( 3042)lamv indexed to bsa ( ml / m)42 ( 3555)edv ( ml)108 ( 82135)lamv ( ml)51 ( 3975)esv ( ml)53 ( 4180)lamv indexed to bsa ( ml / m)26 ( 2137)ef ( % ) 50 ( 3355)pps ( % ) 7.9 ( 6.010.8)laafvlaa ( m / s)0.32 ( 0.121.00)pps / lamv indexed to bsa ( % /ml / m)0.17 ( 0.130.29)evlaa ( m / s)0.26 ( 0.200.44)pps / lamv indexed to bsa ( % /ml / m)0.29 ( 0.180.51)presence thrombi4 patients ( 7.1%)pns ( % ) 0.92 ( 2.3 to 0.53)lala diameter ( mm)46 ( 4351)pns / lamv indexed to bsa ( % /ml / m)0.023 ( 0.049 to 0.012)la area ( cm)26 ( 2331)pns / lamv indexed to bsa ( % /ml / m)0.04 ( 0.078 to 0.017)bsa , body surface area ; edd , end - diastolic diameter ; edv end - diastolic volume ; ef , ejection fraction ; esd end - systolic diameter ; esv , end - systolic volume ; evlaa , emptying velocities of left atrial appendage ; fvlaa , filling velocities of left atrial appendage ; la , left atrium ; laa , left atrial appendage ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; lv , left ventricle ; pps , peak - positive strain ; pns , peak - negative strain . 
  clinical and echocardiographic characteristics of patients . bsa , body surface area ; edd , end - diastolic diameter ; edv end - diastolic volume ; ef , ejection fraction ; esd end - systolic diameter ; esv , end - systolic volume ; evlaa , emptying velocities of left atrial appendage ; fvlaa , filling velocities of left atrial appendage ; la , left atrium ; laa , left atrial appendage ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; lv , left ventricle ; pps , peak - positive strain ; pns , peak - negative strain . echocardiographic parameters by tte and toe study were lv dimensions and ejection fraction , la dimensions and deformation parameters , left atrial appendage ( laa ) filling and emptying velocities , and the presence of la thrombi . prothrombotic status was defined when emptying and filling velocities were < 0.25 m/s ( 14 ) . the success of ecv was established when sr was stable at least 1 day after cardioversion . all patients were evaluated by tte and toe , immediately before ecv , using a vivid digital ultrasound system ( ge medical systems ) . la diameter was measured at end - systole , in parasternal long - axis view . lv diameters were measured at end - diastole and end - systole , in the same imaging plane . la volumes were calculated from an apical four - chamber view ( maximum volume at end - systole ; minimum volume at end - diastole ) . lv volumes were also measured in this imaging plane , and ejection fraction ( lvef ) was calculated . 2d speckle tracking imaging was used to analyse la strain values in six segments . for this purpose , a line was manually drawn along the la endocardium at peak systole in an apical four - chamber view . the software then automatically generated tracking of the la endocardium , which was further adjusted by the operator . the six segments of the left atrium were analysed and an average value of all segments was considered . la function can be evaluated through 2d speckle tracking imaging by analysing its three curve strain components . in sinus rhythm , a qrs - timed analysis identifies the reservoir phase by peak ventricular systolic value ( r ) , which corresponds to maximum atrium filling ; the contractile phase by peak late diastole ( ct ) and the conduit phase by peak early diastole ( cd ) , corresponding to the difference between peaks r and ct ( fig . , it is believed that the reservoir and conduit function are impaired and pump function is lost . thus , in these patients , only peak - positive systolic strain ( pps ) and peak - negative diastolic strain ( pns ) of the curves were analysed , as there was no an accurate way of identifying the different stages of atrial function ( fig . an average of different measurements of la strain curves was taken ( in five consecutive cycles ) in each case . all patients included in the study fulfilled the minimum requirements for analysis by speckle tracking imaging . in sinus rhythm , the qrs - timed analysis identifies the reservoir phase by peak ventricular systolic value ( r ) , which corresponds to the maximum atrium filling ; the contractile phase by peak late diastole ( ct ) and the conduit phase by peak early diastole ( cd ) , corresponding to the difference between peaks r and ct . 
 figure 2la function assessed through 2d speckle tracking imaging in atrial fibrillation . in these circumstances , only peak - positive systolic strain ( pps ) and peak - negative strain ( pns ) of the curves were analysed . , the qrs - timed analysis identifies the reservoir phase by peak ventricular systolic value ( r ) , which corresponds to the maximum atrium filling ; the contractile phase by peak late diastole ( ct ) and the conduit phase by peak early diastole ( cd ) , corresponding to the difference between peaks r and ct . la function assessed through 2d speckle tracking imaging in atrial fibrillation . in these circumstances , only peak - positive systolic strain ( pps ) and peak - negative strain ( pns ) of the curves were analysed . continuous variables were expressed as medians and interquartile range ( iqr ) in line with their non - normal distribution . statistical comparisons were made using the chi - square test or fisher s exact test , as appropriate , for categorical variables , and the mann variables associated in the univariate analysis , or clinically significant in the investigator s opinion , were entered into a forward stepwise logistic regression model to identify variables independently associated with higher thrombotic risk ( odds ratio ( 95% confidence interval ( ci ) for exp ( b ) % ) ) . to predict the discriminatory effect of the peak - positive strain in prothrombotic risk and cardioversion success , the interobserver variabilities of peak - positive and -negative strains were assessed with the intraclass correlation coefficient ( icc ) . one hundred and thirty - three consecutive patients with af or afl undergoing a first ecv between 2010 and 2014 at the hospital vall dhebron , barcelona , were retrospectively evaluated . transthoracic ( tte ) and transoesophageal echocardiography ( tee ) studies were conducted before cardioversion in all patients . exclusion criteria were presence of organic valvular disease ( n=15 ) , prosthetic valves ( n=2 ) , pericarditis or acute myocardial infarction ( n=3 ) , or a recent history of heart surgery or pacemaker implantation ( n=7 ) and without minimum requirements for lad analysis ( n=50 ) . demographics , medical history including the type of arrhythmia ( af or afl ) , duration of the arrhythmia episode classified as paroxysmal ( if it lasted less than 48h ) and as persistent ( lasting days or months ) and other co - morbidities ( hypertension , diabetes , history of stroke and body mass index ) are given in table 1 . table 1clinical and echocardiographic characteristics of patients.demographic characterizationco - morbiditiessexmale36 ( 64%)hypertension39 ( 69.6%)female20 ( 36%)diabetes14 ( 25%)age ( years)67 ( 5974)history of stroke2 ( 3.6%)body mass index ( kg / m)28.8 ( 25.431.6)arrhythmia characterizationtype of arrhythmiaatrial fibrillation39 ( 69.6%)atrial flutter17 ( 30.4%)heart rate ( hr ) during the exam ( beats per minute)100 ( 80125)duration of the episodeparoxysmal ( < 48 h)5 ( 8.9%)persistent ( days)42 ( 75%)persistent ( months)9 ( 16.1%)echocardiographic characterizationlvedd ( mm)49 ( 4555)lalamv ( ml)80 ( 65106)esd ( mm)37 ( 3042)lamv indexed to bsa ( ml / m)42 ( 3555)edv ( ml)108 ( 82135)lamv ( ml)51 ( 3975)esv ( ml)53 ( 4180)lamv indexed to bsa ( ml / m)26 ( 2137)ef ( % ) 50 ( 3355)pps ( % ) 7.9 ( 6.010.8)laafvlaa ( m / s)0.32 ( 0.121.00)pps / lamv indexed to bsa ( % /ml / m)0.17 ( 0.130.29)evlaa ( m / s)0.26 ( 0.200.44)pps / lamv indexed to bsa ( % /ml / m)0.29 ( 0.180.51)presence thrombi4 patients ( 7.1%)pns ( % ) 0.92 ( 2.3 to 0.53)lala diameter ( mm)46 ( 4351)pns / lamv indexed to bsa ( % /ml / m)0.023 ( 0.049 to 0.012)la area ( cm)26 ( 2331)pns / lamv indexed to bsa ( % /ml / m)0.04 ( 0.078 to 0.017)bsa , body surface area ; edd , end - diastolic diameter ; edv end - diastolic volume ; ef , ejection fraction ; esd end - systolic diameter ; esv , end - systolic volume ; evlaa , emptying velocities of left atrial appendage ; fvlaa , filling velocities of left atrial appendage ; la , left atrium ; laa , left atrial appendage ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; lv , left ventricle ; pps , peak - positive strain ; pns , peak - negative strain . 
  clinical and echocardiographic characteristics of patients . bsa , body surface area ; edd , end - diastolic diameter ; edv end - diastolic volume ; ef , ejection fraction ; esd end - systolic diameter ; esv , end - systolic volume ; evlaa , emptying velocities of left atrial appendage ; fvlaa , filling velocities of left atrial appendage ; la , left atrium ; laa , left atrial appendage ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; lv , left ventricle ; pps , peak - positive strain ; pns , peak - negative strain . echocardiographic parameters by tte and toe study were lv dimensions and ejection fraction , la dimensions and deformation parameters , left atrial appendage ( laa ) filling and emptying velocities , and the presence of la thrombi . prothrombotic status was defined when emptying and filling velocities were < 0.25 m/s ( 14 ) . the success of ecv was established when sr was stable at least 1 day after cardioversion . all patients were evaluated by tte and toe , immediately before ecv , using a vivid digital ultrasound system ( ge medical systems ) . la diameter was measured at end - systole , in parasternal long - axis view . lv diameters were measured at end - diastole and end - systole , in the same imaging plane . la volumes were calculated from an apical four - chamber view ( maximum volume at end - systole ; minimum volume at end - diastole ) . lv volumes were also measured in this imaging plane , and ejection fraction ( lvef ) was calculated . 2d speckle tracking imaging was used to analyse la strain values in six segments . for this purpose , a line was manually drawn along the la endocardium at peak systole in an apical four - chamber view . the software then automatically generated tracking of the la endocardium , which was further adjusted by the operator . the six segments of the left atrium were analysed and an average value of all segments was considered . la function can be evaluated through 2d speckle tracking imaging by analysing its three curve strain components . in sinus rhythm , a qrs - timed analysis identifies the reservoir phase by peak ventricular systolic value ( r ) , which corresponds to maximum atrium filling ; the contractile phase by peak late diastole ( ct ) and the conduit phase by peak early diastole ( cd ) , corresponding to the difference between peaks r and ct ( fig . , it is believed that the reservoir and conduit function are impaired and pump function is lost . thus , in these patients , only peak - positive systolic strain ( pps ) and peak - negative diastolic strain ( pns ) of the curves were analysed , as there was no an accurate way of identifying the different stages of atrial function ( fig . an average of different measurements of la strain curves was taken ( in five consecutive cycles ) in each case . all patients included in the study fulfilled the minimum requirements for analysis by speckle tracking imaging . figure 1la function assessed through 2d speckle tracking imaging . in sinus rhythm , the qrs - timed analysis identifies the reservoir phase by peak ventricular systolic value ( r ) , which corresponds to the maximum atrium filling ; the contractile phase by peak late diastole ( ct ) and the conduit phase by peak early diastole ( cd ) , corresponding to the difference between peaks r and ct . 
 figure 2la function assessed through 2d speckle tracking imaging in atrial fibrillation . in these circumstances , only peak - positive systolic strain ( pps ) and peak - negative strain ( pns ) of the curves were analysed . , the qrs - timed analysis identifies the reservoir phase by peak ventricular systolic value ( r ) , which corresponds to the maximum atrium filling ; the contractile phase by peak late diastole ( ct ) and the conduit phase by peak early diastole ( cd ) , corresponding to the difference between peaks r and ct . la function assessed through 2d speckle tracking imaging in atrial fibrillation . in these circumstances , only peak - positive systolic strain ( pps ) and peak - negative strain ( pns ) of the curves were analysed . continuous variables were expressed as medians and interquartile range ( iqr ) in line with their non - normal distribution . statistical comparisons were made using the chi - square test or fisher s exact test , as appropriate , for categorical variables , and the mann variables associated in the univariate analysis , or clinically significant in the investigator s opinion , were entered into a forward stepwise logistic regression model to identify variables independently associated with higher thrombotic risk ( odds ratio ( 95% confidence interval ( ci ) for exp ( b ) % ) ) . to predict the discriminatory effect of the peak - positive strain in prothrombotic risk and cardioversion success , roc curves were performed with its sensitivity and specificity values . the interobserver variabilities of peak - positive and -negative strains were assessed with the intraclass correlation coefficient ( icc ) . most patients had atrial fibrillation ( 69.6% ) , with a persistent character ( 91.1% ) . of the 51 patients with persistent arrhythmia , 42 ( 75% ) had the arrhythmia < 30 days ( median 24 days ; range : 1431 days ) and 9 patients had the arrhythmia > 30 days ( median 115 days ; range : 46280 days ) . the majority of patients had hypertension ( 69.6% ) and only two had a history of stroke ( 3.6% ) . lv systolic function was normal or slightly depressed in 36 patients ( 64.3% ) , and with moderate - to - severe dysfunction ( lvef < 45% ) in 20 ( 35.7% ) . in 27 patients ( 48.2% ) , emptying and filling laa velocities were < 0.25 m/s and normal in 29 ( 51.8% ) . both pps and pns correlated with all la size parameters as given in table 2 . correlation was better with la maximum ( lamv ) and minimum ( lamv ) volumes indexed to body surface area ( bsa ) than with absolute la diameter or area . table 2correlation between heart rate and atrial dimension with peak - positive and -negative strains.ppspnspearson correlationppearson correlationpla diameter0.2740.0410.4210.001la area0.3080.0210.3100.020lamv0.2950.0270.2800.037lamv indexed to bsa0.3750.0040.2670.047lamv0.469<0.0010.3940.003lamv indexed to bsa0.507<0.0010.3740.004bsa , body surface area ; la , left atrium ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; pns , peak - negative strain ; pps , peak - positive strain . bsa , body surface area ; la , left atrium ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; pns , peak - negative strain ; pps , peak - positive strain . the pps correlated with heart rate ( hr ) ( spearman correlation 0.291 ; p 0.030 ) , as opposed to the pns ( spearman correlation 0.149 ; p 0.275 ) . a linear regression model applied verified that hr interferes with approximately 8.5% of the pps value . the interobserver variability of strain parameters was excellent : icc was 0.97 for pps ( 0.960.99 ; p<0.001 ) and 0.93 for pns ( 0.890.96 ; p<0.001 ) . the sample was divided into two groups according to laa velocities : the first with normal velocities and the second with emptying and filling velocities < 0.25 m/s . the second group had higher la volumes and lower pps values , absolute and indexed by bsa ( table 3 ) . table 3correlation between laa velocities and other parameters.with normal velocities in laa ( n=29)with prothrombotic velocities in laa ( n=27)ptype of arrhythmia ( atrial flutter)14 ( 48.3%)3 ( 11.1%)0.003lamv indexed to bsa ( ml / m)40 ( 3443)44 ( 3861)0.021lamv indexed to bsa ( ml / m)23 ( 1827)35 ( 2543)0.001pps ( % ) 8.52 ( 7.4813.88)7.13 ( 5.238.59)0.015pps / lamv indexed to bsa ( % /ml / m)0.25 ( 0.140.36)0.16 ( 0.110.20)0.003pps / lamv indexed to bsa ( % /ml / m)0.46 ( 0.230.60)0.22 ( 0.140.29)0.001presence of thrombi in laa ( number patients)040.048on anticoagulant therapy ( number patients)680.44chads2vasc score2 ( 14)2 ( 23)0.71bsa , body surface area ; laa , left atrial appendage ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; pps , peak - positive strain . bsa , body surface area ; laa , left atrial appendage ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; pps , peak - positive strain . multivariate analysis showed peak - positive strain / la maximum volume indexed by bsa to be associated with laa velocities < 25cm / s ( odds ratio 0.44 ; ( 95% ci : 0.0030.658 ) , p=0.024 ) , regardless of chads2vasc score ( table 4 ) . when we applied the same analysis but with la minimum volume indexed to bsa , and this parameter was also related significantly to laa velocities ( p=0.009 ) but with less significant odds ratio , a measure of association was observed between an exposure and an outcome ( or 0.007 ) . table 4variables included in multivariate analysis of prothrombotic risk.odds ratio95% ciptype of arrhythmia6.8131.45934.5060.012pps / lamv indexed to bsa0.800.7920.9740.014chads2vasc score0.9280.5441.5820.783bsa , body surface area ; dic , dichotomous variable ; lamv , left atrial maximum volume ; pps , peak - positive strain . bsa , body surface area ; dic , dichotomous variable ; lamv , left atrial maximum volume ; pps , peak - positive strain . values of peak - positive strain in relation to la maximum volume indexed to bsa < 0.08 determined the prothrombotic risk ( area under the curve ( auc ) 0.72 , sensitivity 81.5% and specificity 62.1% ) . fifty - two of 56 patients underwent ecv since thrombi in laa , detected in four patients , formally contraindicated the procedure . forty - six converted to sr ( 88% ) while six failed converting to sr ( 12% ) . the success of ecv - obtaining sr was maintained at 3 months of ecv in 44 patients ( 95% ) . pns , in absolute value and in relation to la volumes indexed to bsa , showed lower values in patients who did not convert to sr ( table 5 ) . however , other clinical and echocardiographic parameters such as duration of the arrhythmia , atrial volumes and left ventricle ejection fraction were not related to the efficacy of ecv . 
 table 5correlation between several parameters and cardioversion success.successful cardioversion ( n=46)unsuccessful cardioversion ( n=6)ppersistent arrhythmia ( months duration)7 ( 15.2%)1 ( 16.7%)0.926lvef50 ( 3555)40 ( 3250)0.241lamv indexed to bsa ( ml / m)41 ( 3454)43 ( 3754)0.685lamv indexed to bsa ( ml / m)26 ( 2134)31 ( 2638)0.230pns ( % ) 1.02 ( 2.44 to 0.67)0.55 ( 0.78 to 0.35)0.038pns / lamv indexed to bsa ( % /ml / m)0.026 ( 0.058 to 0.016 ) 0.0111 ( 0.015 to 0.009 ) 0.030pns / lamv indexed to bsa ( % /ml / m)0.042 ( 0.111 to 0.022 ) 0.018 ( 0.023 to 0.012 ) 0.033pps ( % ) 8.25 ( 6.5612.60)6.56 ( 4.888.29)0.128pps / lamv indexed to bsa ( % /ml / m)0.20 ( 0.140.34)0.15 ( 0.110.19)0.160pps / lamv indexed to bsa ( % /ml / m)0.32 ( 0.220.56)0.19 ( 0.140.28)0.089bsa , body surface area ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; lvef , left ventricle ejection fraction ; pns , peak - negative strain ; pps , peak - positive strain . bsa , body surface area ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; lvef , left ventricle ejection fraction ; pns , peak - negative strain ; pps , peak - positive strain . values of peak - positive strain in relation to lamv indexed to bsa > 0.08 determined cardioversion success ( auc 0.74 ; sensitivity 70% and specificity 70% ) ( fig . 3 ) . 
 figure 3roc curve to show sensitivity and specificity of pps to predict cardioversion success . most patients had atrial fibrillation ( 69.6% ) , with a persistent character ( 91.1% ) . of the 51 patients with persistent arrhythmia , 42 ( 75% ) had the arrhythmia < 30 days ( median 24 days ; range : 1431 days ) and 9 patients had the arrhythmia > 30 days ( median 115 days ; range : 46280 days ) . the majority of patients had hypertension ( 69.6% ) and only two had a history of stroke ( 3.6% ) . lv systolic function was normal or slightly depressed in 36 patients ( 64.3% ) , and with moderate - to - severe dysfunction ( lvef < 45% ) in 20 ( 35.7% ) . in 27 patients ( 48.2% ) , emptying and filling laa velocities were < 0.25 m/s and normal in 29 ( 51.8% ) . both pps and pns correlated with all la size parameters as given in table 2 . correlation was better with la maximum ( lamv ) and minimum ( lamv ) volumes indexed to body surface area ( bsa ) than with absolute la diameter or area . table 2correlation between heart rate and atrial dimension with peak - positive and -negative strains.ppspnspearson correlationppearson correlationpla diameter0.2740.0410.4210.001la area0.3080.0210.3100.020lamv0.2950.0270.2800.037lamv indexed to bsa0.3750.0040.2670.047lamv0.469<0.0010.3940.003lamv indexed to bsa0.507<0.0010.3740.004bsa , body surface area ; la , left atrium ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; pns , peak - negative strain ; pps , peak - positive strain . bsa , body surface area ; la , left atrium ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; pns , peak - negative strain ; pps , peak - positive strain . the pps correlated with heart rate ( hr ) ( spearman correlation 0.291 ; p 0.030 ) , as opposed to the pns ( spearman correlation 0.149 ; p 0.275 ) . a linear regression model applied verified that hr interferes with approximately 8.5% of the pps value . the interobserver variability of strain parameters was excellent : icc was 0.97 for pps ( 0.960.99 ; p<0.001 ) and 0.93 for pns ( 0.890.96 ; p<0.001 ) . the sample was divided into two groups according to laa velocities : the first with normal velocities and the second with emptying and filling velocities < 0.25 m/s . the second group had higher la volumes and lower pps values , absolute and indexed by bsa ( table 3 ) . table 3correlation between laa velocities and other parameters.with normal velocities in laa ( n=29)with prothrombotic velocities in laa ( n=27)ptype of arrhythmia ( atrial flutter)14 ( 48.3%)3 ( 11.1%)0.003lamv indexed to bsa ( ml / m)40 ( 3443)44 ( 3861)0.021lamv indexed to bsa ( ml / m)23 ( 1827)35 ( 2543)0.001pps ( % ) 8.52 ( 7.4813.88)7.13 ( 5.238.59)0.015pps / lamv indexed to bsa ( % /ml / m)0.25 ( 0.140.36)0.16 ( 0.110.20)0.003pps / lamv indexed to bsa ( % /ml / m)0.46 ( 0.230.60)0.22 ( 0.140.29)0.001presence of thrombi in laa ( number patients)040.048on anticoagulant therapy ( number patients)680.44chads2vasc score2 ( 14)2 ( 23)0.71bsa , body surface area ; laa , left atrial appendage ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; pps , peak - positive strain . bsa , body surface area ; laa , left atrial appendage ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; pps , peak - positive strain . multivariate analysis showed peak - positive strain / la maximum volume indexed by bsa to be associated with laa velocities < 25cm / s ( odds ratio 0.44 ; ( 95% ci : 0.0030.658 ) , p=0.024 ) , regardless of chads2vasc score ( table 4 ) . when we applied the same analysis but with la minimum volume indexed to bsa , and this parameter was also related significantly to laa velocities ( p=0.009 ) but with less significant odds ratio , a measure of association was observed between an exposure and an outcome ( or 0.007 ) . table 4variables included in multivariate analysis of prothrombotic risk.odds ratio95% ciptype of arrhythmia6.8131.45934.5060.012pps / lamv indexed to bsa0.800.7920.9740.014chads2vasc score0.9280.5441.5820.783bsa , body surface area ; dic , dichotomous variable ; lamv , left atrial maximum volume ; pps , peak - positive strain . bsa , body surface area ; dic , dichotomous variable ; lamv , left atrial maximum volume ; pps , peak - positive strain . values of peak - positive strain in relation to la maximum volume indexed to bsa < 0.08 determined the prothrombotic risk ( area under the curve ( auc ) 0.72 , sensitivity 81.5% and specificity 62.1% ) . fifty - two of 56 patients underwent ecv since thrombi in laa , detected in four patients , formally contraindicated the procedure . forty - six converted to sr ( 88% ) while six failed converting to sr ( 12% ) . the success of ecv - obtaining sr was maintained at 3 months of ecv in 44 patients ( 95% ) . pns , in absolute value and in relation to la volumes indexed to bsa , showed lower values in patients who did not convert to sr ( table 5 ) . however , other clinical and echocardiographic parameters such as duration of the arrhythmia , atrial volumes and left ventricle ejection fraction were not related to the efficacy of ecv . 
 table 5correlation between several parameters and cardioversion success.successful cardioversion ( n=46)unsuccessful cardioversion ( n=6)ppersistent arrhythmia ( months duration)7 ( 15.2%)1 ( 16.7%)0.926lvef50 ( 3555)40 ( 3250)0.241lamv indexed to bsa ( ml / m)41 ( 3454)43 ( 3754)0.685lamv indexed to bsa ( ml / m)26 ( 2134)31 ( 2638)0.230pns ( % ) 1.02 ( 2.44 to 0.67)0.55 ( 0.78 to 0.35)0.038pns / lamv indexed to bsa ( % /ml / m)0.026 ( 0.058 to 0.016 ) 0.0111 ( 0.015 to 0.009 ) 0.030pns / lamv indexed to bsa ( % /ml / m)0.042 ( 0.111 to 0.022 ) 0.018 ( 0.023 to 0.012 ) 0.033pps ( % ) 8.25 ( 6.5612.60)6.56 ( 4.888.29)0.128pps / lamv indexed to bsa ( % /ml / m)0.20 ( 0.140.34)0.15 ( 0.110.19)0.160pps / lamv indexed to bsa ( % /ml / m)0.32 ( 0.220.56)0.19 ( 0.140.28)0.089bsa , body surface area ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; lvef , left ventricle ejection fraction ; pns , peak - negative strain ; pps , peak - positive strain . bsa , body surface area ; lamv , left atrial maximum volume ; lamv , left atrial minimum volume ; lvef , left ventricle ejection fraction ; pns , peak - negative strain ; pps , peak - positive strain . values of peak - positive strain in relation to lamv indexed to bsa > 0.08 determined cardioversion success ( auc 0.74 ; sensitivity 70% and specificity 70% ) ( fig . 3 ) . 
 figure 3roc curve to show sensitivity and specificity of pps to predict cardioversion success . the present study shows la strain to be useful in identifying patients with af or afl with high thrombotic risk , and a good predictor of ecv efficacy . some of these findings concur with the study of azemi and coworkers ( 15 ) , which , in a series of 57 patients showed the relationship between low lad values with high risk of stroke or tia in patients with low chads2 . this correlation was moderate regarding la volumes ( maximum and minimum indexed to bsa ) , a finding already described by vianna - pinton and coworkers in a preliminary study of 84 normal subjects ( 11 ) . those authors also verified that the correlation with la volumes was higher than with la diameter or area . this can be explained by the fact that la enlargement is often asymmetrical and occurs predominantly in the medial  lateral and superior  inferior axes , while being limited in the anteroposterior axis by the thoracic cavity ( 10 ) . therefore , la volumes are considered superior to la diameter as a measurement of la dimension ( 10 ) . thus , in our study , the adjustment of strain values to la dimensions was accomplished by considering its volumes rather than diameter . nevertheless , in our retrospective series , we only systematically obtained the four - chamber view . the thrombotic risk of this population of patients with supraventricular arrhythmias is a crucial issue . this study revealed a significant association between lower pps values and the presence of prothrombotic velocities in laa . the peak - positive strain in relation to la maximum volume was associated with higher thrombotic risk , by multivariate analysis , regardless of the chads2vasc score . this association between la deformation parameters and laa velocities and higher thrombotic risk has been described previously ( 5 , 15 , 16 ) . kaya and coworkers , in their prospective study of 22 patients with af who underwent cardioversion , showed an association between la strain values and laa velocities and observed a progressive improvement over time after ecv ( 5 ) . azemi and coworkers also mentioned a relationship between lower la strain values ( also measured as pps and pns ) and a higher thrombotic risk , when evaluating the occurrence of cerebrovascular events in patients with af ( 15 ) . providncia and coworkers also found a correlation between increased left atrial stasis , assessed through various parameters ( including laa velocities ) , and la mechanical dysfunction assessed with speckle tracking imaging ( 16 ) . therefore , the myocardial deformation parameters appear to be potential non - invasive parameters associated with a higher risk of thrombus in laa ( a contraindication for electrical cardioversion ) and may , therefore , in the future , hypothetically replace invasive techniques such as toe for their evaluation , and be determinants of how long patients should be kept under anticoagulation after cardioversion . the peak - positive strain atrial volume ratio seems to be stronger when its components are separated . the la maximum volume indexed to bsa seems to be a more practical parameter to use in daily practice and was associated with a more significant odds ratio compared with the minimum atrial volume . our data suggest that left atrial mechanical dysfunction , assessed through negative peak longitudinal strain , was associated with the poor success of effective cardioversion , a fact not previously described in the literature . peak - negative strain in this setting of atrial fibrillation can correspond to the residual capacity of myocardial fibres shortening in the absence of an effective atrial contractile function , as part of the la remodelling process . wang and coworkers studied 42 patients and found the early diastolic peak strain rate of the basal segment of the la wall to be a possible predictor of successful cardioversion and maintenance of sr ( 17 ) . in our study , the pns variable isolated or in relation to la volumes was associated with cardioversion failure . remarkably , no other variables such as arrhythmia duration , atrial volumes or left ventricle ejection fraction were associated with ecv success . one of the most significant limitations was the patient population , since small samples may lack statistical power to demonstrate the presence of significant statistical differences . peak - negative longitudinal strain was found to correlate with successful cardioversion , even when the number of patients in the sample was low . therefore , lad may become an important echocardiographic parameter in the clinical decision to perform cardioversion or not in af patients ( 18 ) . another consideration is that the data were obtained using software designed for lv assessment and not specific for la evaluation . nevertheless , this tool permitted the definition and tracking of speckles in the la with a quality of tracking we believe would not improve much further with other software . we chose to evaluate only the six segments of an apical four - chamber view owing to the lack of good la endocardial border definition in the two - chamber view in a considerable number of patients . overall assessment of the various segments of the la in apical two- and four - chamber views may provide more accurate data . we did not perform multivariate analysis given the low number of patients , which would render its interpretation difficult . these findings could have a major clinical impact in the future if confirmed by larger studies . we believe that prospective studies of larger dimensions are required to evaluate myocardial deformation parameters in patients with supraventricular arrhythmias since they seem to provide important information for clinical decision - making regarding the best treatment strategy in this patient population , particularly concerning anticoagulation and cardioversion to sinus rhythm . one of the most significant limitations was the patient population , since small samples may lack statistical power to demonstrate the presence of significant statistical differences . peak - negative longitudinal strain was found to correlate with successful cardioversion , even when the number of patients in the sample was low . therefore , lad may become an important echocardiographic parameter in the clinical decision to perform cardioversion or not in af patients ( 18 ) . another consideration is that the data were obtained using software designed for lv assessment and not specific for la evaluation . nevertheless , this tool permitted the definition and tracking of speckles in the la with a quality of tracking we believe would not improve much further with other software . we chose to evaluate only the six segments of an apical four - chamber view owing to the lack of good la endocardial border definition in the two - chamber view in a considerable number of patients . overall assessment of the various segments of the la in apical two- and four - chamber views may provide more accurate data . we did not perform multivariate analysis given the low number of patients , which would render its interpretation difficult . these findings could have a major clinical impact in the future if confirmed by larger studies . we believe that prospective studies of larger dimensions are required to evaluate myocardial deformation parameters in patients with supraventricular arrhythmias since they seem to provide important information for clinical decision - making regarding the best treatment strategy in this patient population , particularly concerning anticoagulation and cardioversion to sinus rhythm . this study showed that in the near future , atrial deformation parameters could constitute complementary echocardiographic data in the management of patients with atrial fibrillation and atrial flutter . these parameters seem to be able to identify patients who have a higher thrombotic risk and should , therefore , undergo anticoagulant therapy . the parameters also appear to be a good predictor of unsuccessful electrical cardioversion and could be useful in the clinical management strategy of rhythm versus rate control in this patient population . the authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported . this work did not receive any specific grant from any funding agency in the public , commercial or not - for - profit sector .
backgroundleft atrial deformation ( lad ) parameters are new markers of atrial structural remodelling that seem to be affected in atrial fibrillation ( af ) and atrial flutter ( afl ) . 
 this study aimed to determine whether lad can identify patients with a higher risk of thrombosis and unsuccessful electrical cardioversion ( ecv).methodsretrospective study including 56 patients with af or afl undergoing ecv , with previous transthoracic ( tte ) and transoesophageal echocardiography ( tee ) studies . 
 echocardiographic parameters analysed were as follows : left ventricle function , left atrium ( la ) dimensions , lad parameters ( positive and negative strain peaks ) , left atrial appendage ( laa ) filling and emptying velocities and the presence of thrombi . 
 strain values were analysed according to thrombotic risk and success of ecv.resultslower mean values of peak - positive strain ( pps ) in patients with prothrombotic velocities ( < 25 cm / s ) and a higher incidence of thrombi in laa were observed compared with those with normal velocities . 
 multivariate analysis revealed pps normalised by la maximum volume indexed by body surface area ( bsa ) to be associated with prothrombotic risk ( odds ratio 0.000 ( 95% ci : 0.0000.243 ) , p 0.017 ) , regardless of chads2vasc score . 
 peak - negative strain normalised by la volumes indexed by bsa were associated with unsuccessful ecv.conclusionsatrial deformation parameters identify af and afl patients with a high risk of thrombosis and unsuccessful ecv . 
 therefore , these new parameters should be included in anticoagulation management and rhythm vs rate control strategies .