Left atrial (LA) maximal volume contains prognostic information in patients with heart failure and acute myocardial infarction. However, only few studies have investigated the detailed mechanical function of the LA in these patients. We assessed the feasibility of evaluating LA volume and mechanical function with Multi Slice Computed Tomography (MSCT) in patients with ischemic heart disease. Furthermore, the LA and left ventricular (LV) function was evaluated in relation to signs of clinical heart failure. METHODS AND RESULTS: MSCT was performed in 40 patients with sinus rhythm and ischemic heart disease. We enrolled 20 patients with reduced LV ejection fraction (LVEF=45%) and 20 with preserved LVEF (>45%). LA volumes, reservoir, channel and pump function were measured. Interobserver variation for LA volume measures was 1.5% (SD: 6.6%). In patients with reduced LVEF, LA volumes were larger throughout the cardiac cycle (LA-max 66.8 ml/m(2) vs 57.4 ml/m(2) and LA-min: 45.8 ml/m(2) vs 31.6 ml/m(2), p