Cardiac support device
A highly compliant and elastic cardiac support device is provided. The device is constructed from a biocompatible material is applied to an external surface of a heart. The device can be used to resist dilatation of the heart, to provide acute wall support, or to enhance reduction in the size of the heart using stored potential energy, without interfering with systolic contraction.
1. A device for treating diseases of a human heart, the device comprising:
a biocompatible material configured to correspond to an external surface of the human heart, wherein the biocompatible material has a compliance deformable under strain to a stretched state within a range of stretched states defined by the compliance of the biocompatible material, the compliance being the inverse of stiffness;
wherein the compliance of the biocompatible material is greater than a compliance of a normal myocardium;
wherein the biocompatible material has an elasticity that returns the biocompatible material to a rest state from the stretched state;
wherein the elasticity and compliance are selected to store energy within the biocompatible material to assist chronic remodeling of the heart and to avoid acute resistance to diastolic filling of the heart;
wherein the biocompatible material is configured to resist circumferential expansion of the heart but not impede systolic contraction and not over restrain the human heart;
wherein once the device is applied to the external surface of the human heart, no additional energy is required for device functionality; and
wherein the biocompatible material has a stiffness of less than about 3.8 lbs/in (0.68 kg/cm) when subjected to a uniaxial load at a strain of less than 30%.
2. The device according to claim 1 , wherein the biocompatible material is sized to be smaller than the external surface of the human heart to which it is applied, and wherein the biocompatible material is configured to exert a pressure on the external surface of the human heart that is no greater than an end diastolic pressure of a left and/or right ventricle of the human heart.
3. The device according to claim 1 , wherein the biocompatible material is sized to be larger than the external surface of the human heart to which it is applied, and wherein the biocompatible material is configured to be sized by adjustment during implantation.
4. The device according to claim 1 , wherein the biocompatible material is a patch configured to provide dilation constraint and/or acute wall support over the external surface of the human heart without completely surrounding the circumference of the human heart.
5. The device according to claim 1 , wherein the compliance of the biocompatible material is greater than a compliance of a normal latissimus dorsi.
6. The device according to claim 1 , wherein the compliance is a 3-dimensional volumetric compliance that allows at least a 3% increase in volume per 1 mm Hg change in pressure exerted on the external surface of the human heart.
7. The device according to claim 6 , wherein the 3-dimensional volumetric compliance further allows between a 5% and 15% increase in volume per 1 mm Hg change in pressure exerted on the external surface of the human heart.
8. The device according to claim 1 , wherein the elasticity is configured to allow the device to deform elastically up to a desired reduction in cardiac dimension targeted for the chronic potential energy release.
9. The device according to claim 8 , wherein the elasticity has an elastic recovery of at least 50%.