De subitaneis mortibus. XVII. Multifocal stenoses due to fibromuscular dysplasia of the sinus node artery.

The sinus node artery was focally narrowed by fibromuscular dysplasia in two examples of sudden unexpected death reported here. Although both cases had additional histological abnormalities in the conduction system of the heart, the more striking feature was the focal fibromuscular dysplasia. These findings are discussed in relationship to a large number of similar examples of focal fibromuscular dysplastic narrowing of the sinus node artery observed in other victims of sudden unexpected death, considering some possible mechanisms for lethal electrical instability of the heart and also the possible pathogenesis of such fibromuscular dysplasia.