Atypical response of intermittent continuous murmur of patent ductus arteriosus to vasoactive agents, with particular reference to the external and intracardiac phonocardiography.

Abstract

A 20-year-old female with proved patent ductus arteriosus of insignificant left-to-right shunt and intermittent continuous murmur was reported. Once auscultation and phonocardiography revealed a typical continuous murmur, but this was responded unusually by amyl nitrite and methoxamine. Amyl nitrite inhalation initially caused usual response (attenuation of the murmur), but it was followed by unusual intensification. Intravenous administration of methoxamine caused, contrary to the expectation, decrease (first test) or disappearance (second test) of the murmur. The cause of these unusual findings is discussed.