Risk of cardiac complications in surgical patients with bifascicular block.

CHEST, 79: 4, APRIL, 1981 limitation, Simon3 has suggested using an absolute measurement of the transverse heart diameter, and normative data are available. These data, taken from 100 normal chest radiographs, puts the upper limit of normal at 15.5 cm in the male and 14.00 cm in the female (with median values of 12.5 and 11.5 cm respectively). In the 100 chest radiographs reviewed by Simon and myself, the correlation coefficient for thoracic width and transverse heart diameter was 0.59 (p < 0.001) which perhaps justifies the use of the CTR in population studies. In individual cases, however, the ratio does not take account of such variables as the senile chest, where shrinkage and change in shape occur with age, and an absolute measurement may therefore be more appropriate in clinical practice. AdrIan J. Williams, M.B. Co-Director, Pulmonary Function Laboratory, VA Wadsworth Medical Center; Assistant Professor of Medicine, University of California, Los Angeles