Auscultatorily Silent Patent Ductus Arteriosus

Two patients with silent patent ductus arteriosus on auscultation, proved by angiography, are reported. Unlike other reported cases pulmonary pressures were within normal limits, documented by cardiac catheterization. The murmurs of hemodynamically insignificant aortic valve disease were responsible for masking the murmur in one patient and ample subcutaneous tissue damped murmur transmission in the other. A plea for routine use of the hydrogen gas technique as a case-finding method is made because the natural history of such lesions is not known. The risk of infectious endocarditis remains to be determined. Hemodynamic ductal size, patient age, and pulmonary pressures are reasonable criteria for recommending surgical closure of a silent patent ductus, but the objective basis of such recommendations has yet to be clarified.