The straight-back syndrome: radiographic manifestations.

Abstract

Absence of the normal thoracic kyphosis is a relatively recently accepted cause of “pseudoheart disease.” The clini-coradiographic condition has come to be known as the “straight-back syndrome.” The diagnosis can readily be suspected on viewing routine postero-anterior and lateral roentgenograms of the chest. The thoracic malformation was first reported by Raw-lings in 1960 (1), and subsequent reports have appeared in the literature (2–5). Material During the past two years, we have studied 24 patients—12 men and 12 women—in whom loss of thoracic kyphosis was the only somatic fault. A constant clinical feature of all 24 was a heart murmur for which they were referred to the cardiology service of our hospital. The age range was twelve to thirty-six years. Each patient had at least one standard 12-lead electrocardiogram, and thoracic wall phonocardiograms were obtained in all subjects. Seven underwent right heart catheterization during which appropriate hemodynamic tests were performed. The other patients were not catheterized because information derived from the first 7 cases enabled us to recognize the entity with assurance at the clinical level. Radiographically, each patient had one or more sets of postero-anterior and lateral chest films. Radiologic assessment included the cardiothoracic ratio, the cardiac configuration, the degree of shift of the cardiac silhouette, and the prominence of the main pulmonary artery. To gain further information concerning deviations from normal thoracic dimensions, the following measurements were made in the 24 patients and in a normal group of 50 men and 50 women of comparable age: (a) anteroposterior diameters along a perpendicular line from the posterior border of the sternum to the anterior border of the eighth thoracic vertebra and (b) transthoracic diameters at the level of the diaphragm. The ratio of the anteroposterior to the transthoracic diameter was then determined. In the control group the arithmetic means and the standard deviations were obtained separately for men and women. Results Most patients were asymptomatic, and the loss of the normal thoracic kyphosis was apparent on physical examination. The appearance of the thorax was often typical, with the decrease in the anteroposterior diameters of the chest obvious. In each of the 24 patients, there were superficial ejection systolic murmurs that varied in intensity from grade 1 to 3 (out of a possible 6). The murmurs were best heard in the second left interspace. They tended to become amplified during full expiration. Since this study, two of the authors (A. C. de L. and J. K. P.) have observed in some cases amplification of the murmur by chest wall compression. Diastolic murmurs were uniformly absent in our series, although they have been reported (3). Twelve electrocardiograms had vertical axes and rsr patterns in leads V1 or AVR.