Development of a direct systolic cardiac augmentation device.
A direct systolic cardiac augmentation device, called a heart cuff, has been developed. The device is designed to be placed around a "weakened" heart to improve cardiac function. The heart cuff forcibly squeezes the heart during ventricular systole by rhythmically inflating two balloons; one is placed over the left ventricle and the other over the right ventricle. An outer, adjustable, non-distensible cylindrical shell with a liquid-filled liner (bladder) holds the balloons in place. The conformable outer shell and liner inflation allow the device to fit on several different sized and shaped hearts. A purse-string nylon "dome", which is wrapped around the base of the heart and secured in the atrio-ventricular groove, is used to keep the heart cuff in position during assistance. An intra-aortic balloon pump system is used to apply the alternating positive and negative pressures to the balloons. The timing circuitry contained in the system allows for proper inflation/deflation of the balloons corresponding to the contraction/relaxation of the heart using the ECG. Studies show that the heart cuff is capable of being quickly and easily slipped into position, remain in position, and supplement heart function during assistance on normal beating canine hearts.
Frake
B C
BC
Biomedical Engineering Program, Iowa State University, Ames 50011.
Young
D F
DF
Kudej
R K
RK
D000818:Animals; D004285:Dogs; D004867:Equipment Design; D006353:Heart-Assist Devices; D013599:Systole