P2415Normal values for left atrial myocardial and volumetric function in a healthy Dutch population

Background: Incidence of atrial fibrillation (AF) is increasing due to ageing population and electrical cardioversion (ECV) is often overused because of early AF recurrences.Nuclear Magnetic Resonance has explored the mechanisms through which diastolic dysfunction increases risk of nonvalvular AF, underlying left atrial (LA) phasic function quantification potential in unveiling the link between AF and left ventricular (LV) diastolic dysfunction.Purpose: Aim of study was to evaluate value of novel 3D-echocardiographicderived LA conduit (LAC) phasic function quantification in predicting early AF recurrence after ECV.Methods: We included 106 continuous patients (78 males, 74 [64-78] years) who underwent ECV for persistent nonvalvular AF, excluding those with previous history of AF or inadequate echographic apical views.For all a clinical and echoDoppler examination was available before ECV, together with a simultaneous LV-LA 3D full-volume data set.We computed LAC as: [(LV maximum-LV minimum) -(LA maximum-LA minimum) volume], expressed as % of LV stroke volume.AF recurrence was checked with Holter monitoring.Results: At 1 month 66 patients were in sinus rhythm and 40 in AF, for an identical CHA2DS2-VASc (3.0 [2.0-4.0]).Echocardiographic parameters of 2 populations are shown in table.The only difference is higher ejection fraction in AF recurrence patients (p=.05).LA minimum volume (p=.02) and LAC (p<.001) were the only significant AF predictors at multiple regression, even after correction for biometric characteristics and therapy.ROC analysis demonstrated that LAC>68% predicted AF recurrence (100% sensitivity, 50% specificity, area 0.84, p<.001).The analysis for LA minimum volume >45 ml/sqm showed 100% sensitivity, 8% specificity (area 0.56, p=.29, p=.0002 vs. LAC).Sinus Rhythm AF p value LV end-diastolic volume (ml/sqm) 47 [42-61] 52 [42-60] 0.97 Ejection fraction (%) 46 [40-53] 50 [46-54] 0.05 LA minimum volume (ml/sqm) 23 [18-31] 25 [19-32] 0.29 E/Mitral Deceleration Time (ms) 0.59 [0.49-0.082]0.64 [0.51-0.85]0.29 E/E' 8.6 [7.4-10.5]9.1 [7-12.3]0.52 Conduit (%) 48 [36-54] 67 [54-77] <0.01Conclusion: AF causes dependence of LV stroke volume on reciprocation between LA reservoir/conduit phases.Our study suggests that LAC larger contribution to LV filling in AF patients reflects diastolic dysfunction, which skews atrioventricular interaction leading to AF perpetuation and makes LAC a powerful AF recurrence predictor early after ECV.