Our aim was to investigate, in patients with heart failure, the relationship between left atrial size and exercise capacity and cardiovascular events. Seventy-five patients (67 men and 8 women; mean age, 53.4 +/- 8.8 yr) with left ventricular ejection fractions of < or =0.45 (New York Heart Association functional classes I-III) were matched by age and sex with 20 healthy control subjects. Echocardiographic examinations were performed, as was exercise testing by the modified Bruce protocol. Patients were monitored for a period of 330 to 480 days for cardiac death or for heart failure that required hospitalization. The indexed left atrial diastolic size (beta level = -0.534, P <0.001) and left ventricular late diastolic filling velocity (beta level = 0.247, P <0.017) were the most important values in predicting low exercise capacity. The only independent predictor of low exercise capacity (<5 METS) was the indexed left atrial diastolic size (odds ratio, 1.428; 95% confidence interval, 1.09-1.702; P <0.001). Every 1 mm/m2 increase in indexed left atrial diastolic dimension caused a 42.8% increase in the risk of severe heart failure (exercise capacity, <5 METS). Independent predictors for cardiovascular events were indexed as left atrial systolic size (odds ratio, 1.383; 95% confidence interval, 1.145-1.671; P <0.001) and left ventricular early diastolic/late diastolic filling velocity (odds ratio, 1.096; 95% confidence interval, 1.010-1.189; P <0.027). Indexed left atrial diastolic and left atrial systolic size predict exercise capacity and cardiovascular events, respectively, in New York Heart Association functional class I through III heart failure patients.
Keywords: Atrial function, left/physiology; ROC curve; cardiac output; cardiomegaly, dilated/ultrasonography; diastole; exercise test; exercise tolerance/physiology; exertion; heart atria; heart failure; myocardial contraction; predictive value of tests; prognosis; stroke volume; systole.