Since ligation of a patent ductus arteriosus is now a popular and effective operation, it is of practical interest to consider other cardiac conditions that, by producing a similar murmur, may lead to a pre-operative error in diagnosis. If the " mill-wheel" or " machinery" murmur of patent ductus arteriosus has not fully developed, the error may be one of oversight, but confusion may also arise when a similar murmur is produced by other defects. These defects all include a free leak from the aorta above the cusps, and may be either congenital or acquired. If the defect be one in the aortic septum, the murmur may date from birth, and in such a case the expectation of life is not above fourteen years (Dadds and Hoyle, 1949). A similar murmur may follow rupture of a congenital aneurysm of the sinus of Valsalva into the pulmonary conus and may occur at twelve years or not until the patient is over forty years of age (Morgan Jones and Langley, 1949). These authors also described similar rupture of two acquired sinus aneurysms, one possibly due to rheumatism, but the best recognized acquired lesion to produce the mill-wheel murmur is a fistula between a syphilitic aneurysm of the first part of the aortic arch and the pulmonary artery. The following description is of a case of this kind.Case Report History. A factory manager, aged 44 years, was admitted with a history of very good health and good athletic record till two years previously. He then began to notice slight dyspnoea on exertion, which increased gradually till two months before his admission, when he became much more dyspnoeic at all times and was in particular subject to acute attacks of dyspnoea at night. A few nights before admission he had severe vomiting, and when admitted he was still trying to make himself vomit and occasionally succeeded in raising a little blood-tinged sputum. He was very nervous and worried, and complained of severe epigastric tightness and discomfort.Physical examination. A well developed, muscular man, afebrile, orthopnceic, markedly dyspnoeic and moderately cyanosed. The neck veins were filled nearly to angle of jaw and pulsated visibly. The heart showed a rather diffuse apical impulse just external to the nipple line in the fifth left space. A loud systolic and diastolic " mill-wheel " murmur was heard all over the precordium, loudest in the pulmonary area, where it was accompanied by a synchronous palpable thrill. The heart rate was at 116 a minute.The blood pressure was 130/50. The left base showed many rales, and a moderate pleural effusion covered the right base and lower axilla.The liver was tender and smooth, extending 8 cm. below the right costal margin. Moderate cedema of sacrum, feet and ankles was present.Investigations. An X-ray of the chest showed much dilatation of the pulmonary artery and conus, and heavy shadows of the pulmonary branches, with some congestion of the lung bases (Fig. 1). An electrocardiogram showed sinus tachycardia and a tendency to right axis deviation. Lead I showed a good voltage RS and lead I...
