Left atrial size and left ventricular function in coronary artery disease: An echocardiographic‐angiographic correlative study

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Abstract
M‐mode echocardiography was used to determine left atrial size in 100 patients with coronary artery disease undergoing cardiac catheterization. Patients were divided in two groups on the basis of left atrial diameter (≥ 40 mm in 40 patients and < 40 mm in 60). Patients with larger left atria had a higher frequency of electrocardiographic evidence of left atrial abnormality (p < 0.01) and myocardial infarction (p < 0.001). Pulmonary capillary wedge and left ventricular end‐diastolic pressures were higher (p < 0.005) in patients with larger left atria. An abnormal end‐diastolic volume (>100 ml/M2) was observed in 13 patients with enlarged left atria compared to none with normal left atrial size (p < 0.001). Triple vessel disease was more frequent (63% vs 32%) and single vessel disease less frequent (10% vs 37%) in patients with larger left atria (p < 0.005). Abnormal left ventricular contractile patterns were noted in 45% of patients with normal left atrial diameters compared to 80% in those with an enlarged left atrium (p < 0.001). An abnormally low ejection fraction (< 0.5) was observed in 25% and 80%, respectively, in patients with normal and enlarged left atria (p < 0.001). Of 58 patients with normal ejection fractions, only 17% had left atrial diameters ≥40 mm compared to 71% of 42 patients with abnormally low ejection fractions (p < 0.001). Of 18 patients with left atrial diameters > 42 mm, only two had normal ejection fractions. The mean ejection fraction for patients with left atrial diameters <40 mm was 0.63 ± 0.13 compared to 0.41 ± 0.18 for those with diameters ≥40 mm (p < 0.001). The sensitivity, specificity, and predictive value for an enlarged left atrium in identifying an abnormal ejection fraction were, respectively, 71, 83, and 75%. These findings indicate that M‐mode echocardiographic left atrial enlargement is a useful marker of advanced hemodynamic and anglographic abnormality in patients with coronary artery disease.