External counterpulsation cardiac assist device

Abstract

The cardiac assist device includes a sealed tubular housing for externally applying positive and negative relative pressure to a limb in counterpulsation with heart function. The applicator is assembled, in situ, to provide customized fit. It includes a fabric or sponge-like inner layer cut to size and situated around the limb. Initially deformable material is sized, sealed around the inner fabric layer and then secured by straps or the like to form a relatively rigid, non-expandable tubular shell. The shell may include an interior wall composed of a sheet of hard plastic or articulated sections of hard plastic or metal. The interior wall has a plurality of openings to the sealed shell interior. The exterior shell wall is positioned around the interior wall. The shell walls are spaced apart by radially and/or longitudinally extending spacer elements defining a multi-section air flow chamber between the walls. The interior shell wall and spacer elements may be integral. The spacer elements include passages such that air pumped into and out of the shell chamber is uniformly distributed and moves freely to and from the shell interior. A heater may be used to regulate the air temperature to promote vascular dilation.