Pneumatic or hydraulic cardiac assist devices
The embodiments relate to cardiac assist devices that comprise a jacket that wraps the exterior of the heart, where the jacket comprises one or more pneumatic or hydraulic bladders. The pneumatic or hydraulic bladders are linked to a pump, and the pump fills the bladders with fluid and withdraws the fluid in a cycle to match beats of the heart to assist contraction and pumping of the heart in systole or to assist expansion and filling of the heart in diastole.
1. A device for treating cardiac disease comprising:
(a) a cardiac jacket configured to fit generally around the heart of a mammal, the jacket comprising an inner layer proximal to the heart and an outer layer distal to the heart, each composed of a biocompatible material, the inner and outer layers coupled to form one or more fluid-tight seals that define (i) one or more chambers collectively configured to generally overlay the right ventricle, which are the right chamber or chambers, and (ii) one or more chambers collectively configured to generally overlay the left ventricle, which are the left chamber or chambers;
(b) a first fluid passageway linked to the right chamber or chambers;
(c) a second fluid passageway linked to the left chamber or chambers;
(d) a fluid reservoir linked to the first and second fluid passageways; and
(e) a pump linked to the fluid reservoir and configured to pump fluid from the fluid reservoir into right chamber or chambers and the left chamber or chambers and to withdraw the fluid from the chambers in a cycle to expand the left chambers and/or the right chambers during systole and contract the chambers during diastole to assist systolic pumping of the heart or diastolic refilling of the heart or both;
wherein the chambers do not cover the apex of the heart and in operation the jacket does not compress the apex of the heart upward;
wherein the right chamber or chambers are fluidically separated from the left chamber or chambers except through the fluid reservoir;
wherein the left chamber or chambers are delimited in part by a seam coupling the inner and outer layers and configured to overlay the anterior sulcus of the heart, and by a seam coupling the inner and outer layers and configured to overlay the posterior sulcus of the heart;
wherein the device is configured to allow an operator to (i) adjust pressure or time course of pressure exerted on the left or right ventricle in diastole by the device or maximum expansion volume of the left or right ventricle allowed by the device in diastole, or (ii) adjust the pressure or the time course of pressure exerted on the left or right ventricle in systole by the device or the minimum volume of the left or right ventricle in systole, or both (i) and (ii);
wherein the device is configured to allow adjustment of the maximum expansion volume of the left or right ventricle during diastole that is allowed by the device by altering the amount of fluid in the left chamber or chambers or the right chamber or chambers at the point of maximum diastolic expansion of the left or right ventricle.
2. The device of claim 1 , wherein the device is configured to exert different pressures on the left and right ventricles during systole.
3. The device of claim 2 wherein the device is configured to exert pressure on the left or right ventricle in systole and substantially no pressure on the other ventricle in systole.
4. The device of claim 1 wherein the device is configured to exert pressure on the left or right ventricle during diastolic expansion of the ventricles before maximum expansion during diastole of the ventricle or ventricles against which pressure is exerted.
5. The device of claim 1 wherein the device is configured to exert negative pressure on the left or right ventricle during diastolic expansion of the ventricles to assist the left or right ventricle with diastolic expansion.
6. The device of claim 5 wherein the device is further configured to exert on the ventricle or ventricles that receive negative pressure during diastolic expansion positive pressure at or near the point of maximum diastolic expansion of the ventricle or ventricles.
7. The device of claim 1 wherein the device is configured to allow separate adjustment of the maximum expansion volume of the left and right ventricles during diastole that is allowed by the device by altering the amount of fluid in the left and right chambers of the device at the point of maximum diastolic expansion of the ventricle.