Two-dimensional Echocardiographic Assessment of Electrocardiographic Criteria for Right Atrial Enlargement

Right atrial (RA) size was determined with two-dimensional echocardiography using the apical four-chamber view in 45 adult patients with various echocardiographic criteria for RA enlargement and in 25 normal controls. RA size varied from 11.4-24.0 cm² (mean 16.1 cm²) in controls. RA enlargement (2 25 cm²) was found in only two of 11 patients with P pulmonale (predictive value [PVJ = 18%) and one of five with prominent positive P-wave forces in lead V, (PV = 20%). However, RA enlargement was found in eight of eight patients wh a qR pattern in lead V1 in the absence of clinical indications of coronary artery disease (PV = 100%). RA enlargement was also found in 13 of 28 patients with a total QRS amplitude in lead V, of 6 mm or less and a threefold or greater ratio of total QRS amplitude in lead V, relative to that in V, (V2/V1 2 3) (PV = 48%). A V2/V, ratio of 4 or more detected 11 of 13 patients with RA enlargement, with six false-positive diagnoses (sensitivity = 85%, specificity = 60%, PV = 65%). The combination of total QRS amplitude in V, of 4 mm or less, together with a Vj/V, ratio of 5 or more, detected six of 11 with RA enlargement, with one false-positive diagnosis (sensitivity = 46%, specificity = 93%, PV = 86%). We conclude that ECG criteria for RA enlargement that primarily use increased P-wave amplitude have a limited PV. The qR pattern in lead V, appears to be extremely accurate in detecting RA enlargement. ECG criteria in leads V, and V2 using decreased amplitude in leads V, and a V2/V, 2 3 are of some value in detecting RA enlargement.