From monster to reversed perfusion

Abstract

A human being born without heart and head, the acardius/acranius malformation, has been described since antiquity. Superstition and fear made it a mystical disorder, a sign of God’s wrath. The inquisition ruled that acranic infants should not be baptized and located the soul in the brain. Acardia was not associated with twin gestation until the reports of Méry (1720) and Winslow (1740) were published in Paris. In 1850, Meckel identified the pathogenetic mechanism as reversed perfusion due to large arterioarterial and venovenous anastomoses; he believed the heart would fail to develop or stop during development, and the acardiac fetus would be maintained by arterial perfusion from the pump twin. In 1859, Claudius articulated that after normal initial development, the heart degenerates when backwards flow in the aorta leads to thrombosis. Today, it is assumed that both mechanisms may exist. With the advent of prenatal ultrasound diagnosis and radiofrequency ablation of the acardiac twin’s circulation, it became possible to save the pump twin.