The "straight back" syndrome: current perspective more often associated with valvular heart disease than pseudoheart disease: a prospective clinical, electrocardiographic, roentgenographic, and echocardiographic study of 50 patients.

Fifty consecutive patients (36 male, 14 female, mean age 28 years) who had heart murmurs and clinical and radiographic evidence of straight upper dorsal spine (straight back syndrome, SBS) underwent detailed clinical, electrocardiographic, roentgenographic, and echocardiographic evaluation. Palpable systolic thrill noted in one (2%) and widened S2 with persistent splitting in 2 (4%) patients were uncommon. Murmurs were invariably systolic in nature. Those located at the base of the heart in 19 (38%) patients were ejection in type and best heard during expiration. Those located at the apex in 26 (52%) patients were either mid-, late-, or pansystolic, and often associated with midsystolic click. Five (10%) patients had both types of murmurs. Diastolic murmurs were not heard in any patient. EKGs were normal in the majority. Cardiomegaly (C:T greater than 55%) was present in only 5 (10%) and dilatation of the main pulmonary artery in 2 (4%) patients. Thus the incidence of pseudoheart disease (PsHD) was small (14%). Echocardiograms were normal in 18 (36%) and abnormal in 32 (64%) patients. There was evidence of mitral valve prolapse (MVP) in 29 (58%) patients and 3 (6%) had evidence of bicuspid aortic valve (BAV). In a control group of 40 age- and sex-matched patients (26 male, 14 female, mean age 29.5 years), who also had heart murmurs but lacked straight upper dorsal spine, only 7 (17.5%) had MVP and none had BAV. The difference is both clinically and statistically significant (p less than 0.001). It is concluded that SBS is more often associated with valvular heart disease (MVP and BAV) than PsHD. Therefore, the diagnosis of SBS should remain presumptive until echocardiography has been performed to exclude MVP and BAV. SBS patients who have valvular heart disease should receive infective endocarditis prophylaxis.