Apparatus and method for adjusting heart/pacer relative to changes in venous ...

United States Patent im

Schroeppel

[li] Patent Number: 4,770,177 [45] Date of Patent: Sep. 13,1988

[54] APPARATUS AND METHOD FOR

ADJUSTING HEART/PACER RELATIVE TO
CHANGES IN VENOUS DIAMETER DURING
EXERCISE TO OBTAIN A REQUIRED
CARDIAC OUTPUT.

[75] Inventor: Edward A. Schroeppel, Miratnar, Fla.

[73] Assignee: Telectronics N.V., Netherlands, Netherlands Antilles

[21] Appl. No.: 830,089

[22] Filed: Feb. 18,1986

[51] Int. Q.* A61N1/36

[52] U.S. a 128/419 PG; 128/670;

128/786

[58] Field of Search 128/419 P, 419 PG, 663,

128/670, 672, 673, 687, 691, 692, 694, 695, 713, 774, 782, 784, 786

[56] References Cited

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OTHER PUBLICATIONS

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Primary Examiner—William E. Kamm

Attorney, Agent, or Firm—Thomas R. Vigil; Henry W.

Collins

[57] ABSTRACT

The apparatus paces a heart in accordance with the heart/pacer rate needed to produce a required cardiac output while a person is exercising or undergoes emotional stress in response to changes in venous blood vessel diameter. The apparatus includes a pacer adapted to be implanted in a human body and having a pulse generator and control circuitry, which may be realized by a microprocessor, therein; a pacing lead adapted to be implanted in a heart having a tip electrode adapted to engage and supply pacing pulses to a right ventricle of a heart; a piezoelectric sensor for determining changes in diameter of a vein in the human body; and computing circuitry including the control circuitry, for relating the changes in venous blood vessel diameter with the required pacing rate needed to supply a desired cardiac output and for causing the pacer to pace the heart at the required rate when the heart is not naturally paced.

18 Claims, 3 Drawing Sheets