D. Cozma

496 Left atrial surface cut point to detect trapezoidal shape for characterisation of atrial anatomical remodeling

BACKGROUND Complete geometrical and shape characterization of left atrium has not been performed. Ellipse formula has been proved to underestimate the real LA volume. The aim of the study is to analyze the relation between LA area and shape in order to predict their value in the assessment of the severity of anatomical remodeling. METHODS 216 consecutive patients (pts) aged 53 +/- 27 years were included. The following parameters were assessed: LA dimensions (LAd=M-mode, parasternal long axis, LAt and LA1 are the measurements of short- and long-axis in apical four chamber view), LA surface in apical four chamber view (LAs). A new measurement was introduced, the basal dimension of the LA (LAb) as the maximal transverse distance at the base of LA apical four chamber view. LA measurements were calculated at end-systole (maximal). Trapezoidal LA shape was defined if transverse dimension < basal dimension. RESULTS LAs ranged 10.5-54.5 cm2. Trapezoidal LA was found in 149 pts. ROC curve for prediction trapezoidal LA showed a 0.89 area under the curve. The analysis demonstrates a cutoff value of 22.3 cm2 for LAs to detect trapezoidal shape with a sensitivity of 85% and specificity of 82.5%. The simple regression analysis demonstrated a statistically significant linear correlation between LAd and LAs (r2=0.63, p<0.0001) but LA1 was better correlated with LAs (r2=0.7, p<0.0001). Trapezoid LA with atrialization of the pulmonary veins and predominant dilatation of bazal atrium than annular side may explain underestimation of LA volume using ellipse formula. CONCLUSION LAs is a reliable parameter and may be the best choice to estimate LA dilatation; LAs is related to shape remodeling; LA1 is a better parameter than LAd for estimating LA dilatation and complete characterization of LA remodeling should include shape definition and LAb.

168 Echocardiographic evidences of increased left ventricular pressure and atrial dilatation in patients with drug-resistant paroxystic atrial fibrillation and structurally normal heart

UNLABELLED Global myocardial index (GMI) has been significantly related to left ventricular filling pressure. We hypothesized that GMI and echographic indicators of atrial dilatation were significantly different in pAF pts compared to normals. METHODS 39 patients (pts) without structural heart disease, aged 52+/-10 years with pAF were compared to 36 control-matched pts aged 48+/-16 years. Following parameters were assessed: P-wave duration (Pd), GMI, left atrial dimensions (LAd=M-mode, parasternal, LAt and LAI are measurements of short and long-axis apical four chamber view), surface (LAs), volume (LAv), total ejection fraction (LA EF), right atrial dimension (RAd) and surface (RAs), total atrial surface (TAs=LAs+RAs). LAv was calculated using ellipse formula pi/6 (LAdxLAlxLAt). RESULTS There was no difference between the 2 groups concerning Pd (p=0.1), LA EF (p=0.23), LAd (p=0.08) and LAt (p=0.06) while the rest of the parameters were significantly higher in pAF pts: GMI: 0.5+/-0.17 vs 0.36+/-0.06 (p=0.001); LAI: 5.4+/-0.5 vs 4.5+/-0.3 cm2 (p=0.001); LAs was founded increased in pAF pts (20.6+/-5.7 vs 16.3+/-2.1 cm2, p=0.001); TAs: 40.6+/-6.9 vs 30.6+/-5.1 cm2, p=0.0001; LAv: 51.6+/-10.4 vs 37.2+/-9.3 ml (p=0.0001). CONCLUSIONS Although apparently without structural heart disease, pAF pts presented evidence of increased filling pressions in left ventricle and indirect markers of atrial stretch. The role of increased intra-atrial pressure in pts pFA and predictive value of these parameters need to be evaluated in a larger number of patients.