Left atrial volume: an old echocardiographic measure with renewed prognostic significance: a study in patients with dilated cardiomyopathy

Abstract

Left atrial enlargement is common in many cardiac diseases; a major determinant of this enlargement is left ventricular diastolic pressure. Left atrial volume (LAV) has recently been linked to adverse prognosis. The objective of our study was to assess LAV as a prognostic marker in patients with dilated cardiomyopathy (DCM) and to correlate LAV with other known prognostic factors such as maximum oxygen consumption (VO2 max) and pro-B-type natriuretic peptide (pro-BNP).

Methods: Our population consisted of 35 patients with DCM followed regularly in our hospital and with mean ejection fraction (EF) of 31+/-9.6%. All patients underwent routine 2D Doppler echocardiographic examination, TDI was used to obtain early peak velocity of the mitral annulus, and LAV was calculated using Simpson's method of disks. Pro-BNP was measured and cardiopulmonary exercise testing was also carried out. Mean follow-up was 24+/-4 months and new hospital admission due to heart failure, cardiac transplantation and death were considered cardiac events.

Results: All two-dimensional (left ventricular dimensions and volumes and EF) and conventional Doppler echocardiographic parameters (mitral inflow) were analyzed; mean LAV was 78.6+/-33 ml. Age and gender had no influence on LAV. LAV (and LAV indexed to body surface area [BSA]) showed an inverse correlation with VO2max (r=-0.48, p=0.008) and with pro-BNP (r=0.43, p=0.02). With regard to prognosis, LAV and LAV/BSA were associated with cardiac events (r=0.4, p=0.02), like other classic prognostic markers (EF, left ventricular volumes, mitral regurgitation and E/E'). The cut-off values of LAV and LAV/BSA for cardiac events on ROC curve analysis were 70 ml and 38 ml/m2 respectively.

Conclusions: LAV (LAV/BSA) has incremental prognostic value in patients with dilated cardiomyopathy and correlates with exercise tolerance and pro-BNP.