The bruit of carotid stenosis versus radiated basal heart murmurs. Differentiation by phonoangiography.

Phonoangiography, quantitative analysis of arterial bruits, has been shown to provide accurate noninvasive diagnosis of uncomplicated carotid arterial stenosis, but had not been tested where cervical bruits from other sources were present. In this study, 27 carotid bruits in 15 consecutive patients with carotid bruits and basal heart murmurs were analyzed by phonoangiography. Tape recordings were made over the base of the heart and along the course of the carotid arteries in the neck; spectral analysis was performed as previously described. The spectral shape of the basal heart murmurs was recognizable and amplitude decreased with distance from the heart, althouth a secondary, lower amplitude, maximum often occurred over the carotid bifurcation. Intrinsic carotid bruits, by contrast, were always maximal over the bifurcation, and although they radiated both proximally and distally, were not detectable over the chest wall. In quantitative terms, the correct diagnosis as to the presence and extent of carotid stenosis was made in 25 of 27 cases (92%) despite the presence of a radiated murmur. Phonoangiography is capable of accurate differentiation of radiated murmurs from intrinsic carotid bruits and of quantitation of the latter even in the presence of radiated sounds.