Right Atrial Volume Measurements

Right atrial (RA) volumes were calculated from biplane cineangiocardiograms obtained during diagnostic cardiac catheterization in twenty-nine patients with normal right hearts. Validation of methodology was performed with calculations of right atrial casts of 14 human right atria. An excellent correlation of known and calculated volume was obtained either with a Simpson's rule method, r = 0.999, or with the area-length method assuming an ellipsoid of revolution, r = 0.998. The relationship between patient size and RA maximal volume (RA Max) was best fit by an exponential equation relating RA Max to body surface area: [RA Max= 54.6 (BSA)1.233, r = 0.979, F ratio 561.8]. RA Max normalized for body size was significantly less for infants less than one year of age than for older patients. RA Max averaged 38% greater than LA Max in the normal group. RA Max was evaluated in 14 patients with atrial septal defect or anomalous pulnonary venous return. These patients all showed increases in RA Max averaging 198% of normal. RA Max/BSA showed a significant correlation with Qp/Qs derived from 02 data, r= 0.805. RA Max was increased in six of fourteen patients with moderate to severe pulmonary stenosis. The ratio of RA Max/LA Max was increased in the pulmonary stenosis group. These data provide the initial values for right atrial volume quantitation in man. RA Max can be estimated accurately from biplane cineangiograms and can aid in evaluation of alterations in right heart structure and function.