The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 18, 1987
Filed:
Mar. 29, 1982
Rodney W Salo, Columbia Heights, MN (US);
Brian D Pederson, St. Paul, MN (US);
Cardiac Pacemakers, Inc., St. Paul, MN (US);
Abstract
A biomedical apparatus capable of sensing changes in the heart's ventricular volume or stroke volume and then changing the operating performance of the device in a fashion as a function of stroke volume. A relatively low frequency signal (under 5 KHz) is applied between spaced electrodes disposed in the heart and the beating action of the heart serves to modulate this signal due to changes in impedance being sensed between these or other electrodes within the heart. The modulated carrier signal is then processed to remove R-wave and other electrical artifacts and then demodulated to remove the carrier frequency component leaving the envelope which is proportional to instantaneous ventricular volume. This envelope signal then contains stroke volume and ventricular volume information which can be used by the biomedical apparatus to vary its operating parameters. For example, a current proportional to changes in stroke volume may be injected into the timing circuit of a demand-type cardiac pacer pulse generator whereby the interpulse interval of the pulse generator is varied as a function of stroke volume.