Poor relationship between left atrial diameter and volume in patients with atrial fibrillation

AbstractBackgroundLeft atrial (LA) enlargement is a predictor of worse outcome after catheter ablation for atrial fibrillation (AF). We investigated the correspondence between single LA diameter (LAd) and LA volume (LAV) in patients undergoing catheter ablation for AF.MethodsTotal 782 patients (aged 58±11 yrs; 70% males; 56% paroxysmal AF) were enroled in 2 centres in the period of 2007–2011. Echocardiographic antero-posterior LAd was assessed in parasternal long-axis view and LAV was derived from electroanatomic 3D reconstruction of LA (183±50 CARTO mapping points; 55% CT image registration).ResultsMean LAd was 45±6mm (median: 45; IQR: 41–49; range: 25–73mm) and mean LAV was 134±42ml (median: 128; IQR: 103–160; range: 46–313ml). Correlation between both variables was weak (r=0.56; p <0.0001) and area under the ROC curve for the LAd-based prediction of LAV >130 was 0.76. Accordingly, severe dilation of LA (LAV >160ml; upper quartile) was found only in 56% of patients with LAd >50mm while it appeared in 11% of those with LAd