Non-blood contacting mechanical device that improves heart function after injury

Abstract

A method and device are provided for non-blood contact mechanically assisting an injured (e.g., infarcted) ventricle by coupling an inflatable bladder or other volume adjustable device to the injured ventricle and selectively inflating the bladder or increasing the size of the volume in systole to apply force against the injured ventricle and deflating the bladder or reducing the size of the volume in diastole to remove force against the injured ventricle. When no mechanical assistance is being provided to the injured ventricle, the inflatable bladder or volume adjustable device is preferably maintained at a predetermined pressure so as to selectively stiffen the injured tissue and alter ventricular geometry a desired amount. The method is implemented by a mechanical assist device including the volume adjustable device, a coupling means that couples the volume adjustable device to the injured ventricle, a pulsatile device that selectively increases and decreases the volume of the volume adjustable device, and a controller responsive to the pace of the heart and adapted to selectively change the size of the volume adjusting device in different modes of operation.

What is claimed: 
     
         1 . A method of mechanically assisting an injured heart ventricle, comprising:
 coupling an elastic fluid fill chamber to the injured ventricle; and   selectively adjusting a volume of the fill chamber in systole to apply force against the injured ventricle and emptying the fill chamber in diastole to remove force against the injured ventricle.   
     
     
         2 . The method of  claim 1 , further comprising maintaining the volume of the fill chamber at a predetermined volume so as to selectively stiffen the injured ventricle a desired amount. 
     
     
         3 . The method of  claim 1 , wherein the force applied by the fill chamber is sufficient to variably alter a geometry of the injured ventricle to a pre-injury shape by eliminating a cavity volume of the ventricle bounded by the injured ventricle tissue. 
     
     
         4 . The method of  claim 1 , wherein the force applied by the fill chamber is sufficient to redirect blood volume from a non-contractile injured region of the ventricle to an uninjured contractile remote region of the ventricle. 
     
     
         5 . A mechanical assist device for providing active assistance to an injured ventricle, comprising:
 an elastic fluid fill chamber;   means for coupling said fill chamber to the injured ventricle; and   means for selectively adjusting a volume of the fill chamber in systole to apply force against the injured ventricle and emptying the fill chamber in diastole to remove force against the injured ventricle.   
     
     
         6 . The mechanical assist device of  claim 5 , wherein the means for selectively adjusting the volume of the fill chamber includes a controller responsive to the pace of the heart and adapted to selectively expand the volume of the fill chamber in systole to apply force against the injured ventricle and to selectively reduce the volume of the fill chamber in diastole to remove force against the injured ventricle. 
     
     
         7 . The mechanical assist device of  claim 6 , wherein the fill chamber is a bladder having a volume that is selectively filled with fluid provided by a fluid fill port under control of a pulsatile device responsive to said controller. 
     
     
         8 . The mechanical assist device of  claim 6 , wherein the fill chamber is maintained at a predetermined volume to selectively stiffen the injured ventricle and/or to alter the ventricle geometry a desired amount when the controller is inoperative. 
     
     
         9 . The mechanical assist device of  claim 5 , wherein the fill chamber is adapted to be implanted in a patient on epicardial tissue so as not to contact blood being pumped by the patient's heart. 
     
     
         10 . The mechanical assist device of  claim 5 , wherein the fill chamber has an inelastic outer shell. 
     
     
         11 . The mechanical assist device of  claim 5 , wherein the coupling means comprises sutures. 
     
     
         12 . The mechanical assist device of  claim 5 , wherein the fill chamber is a bladder having a first portion for accepting a first fluid and a second portion for accepting a second fluid provided by first and second fill ports. 
     
     
         13 . The mechanical assist device of  claim 5 , wherein the fill chamber has a plurality of bladders adapted to accept liquid and/or gas from a plurality of fill ports. 
     
     
         14 . The mechanical assist device of  claim 5 , wherein the means for selectively adjusting the volume of the fill chamber is adapted to operate in a static mode where the fill chamber is affixed over the injured ventricle and filled with fluid to a predetermined volume, a synchronous dynamic mode that times expansion and reduction of the fill volume with a cardiac cycle of the heart, and/or an asynchronous dynamic mode in which an amplitude, frequency, and/or duration of the adjustment of the volume of the fill chamber is adjusted independent of the cardiac cycle of the heart. 
     
     
         15 . A mechanical assist device for selectively stiffening injured tissue of a ventricle and/or to alter ventricle geometry a desired amount, comprising:
 a material configured to change size of the ventricle when affixed to the injured tissue so as not to contact blood being pumped by the patient's heart; and   means for coupling the solid material to the injured tissue.   
     
     
         16 . The mechanical assist device of  claim 14 , wherein the position, size, and volume of the material is individualized for a patient. 
     
     
         17 . The mechanical assist device of  claim 14 , wherein the material is a solid material. 
     
     
         18 . The mechanical assist device of  claim 14 , wherein the material comprises a bladder filled with fluid to a predetermined volume. 
     
     
         19 . The mechanical assist device of  claim 14 , wherein the material is a self expanding wire mesh.