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:
Jul. 13, 1976
Filed:
Jan. 24, 1975
Joseph A Ballis, Roseville, MN (US);
Medtronic, Inc., Minneapolis, MN (US);
Abstract
A cautery protection circuit is disclosed for use with a heart pacemaker and comprises circuit elements for preventing those signals induced within the output portion of the heart pacemaker circuit by an electric field established by cautery procedures, from being rendered unsymmetrical in wave form, thereby minimizing the possible adverse effects of such induced signals, e.g. fibrillation of the patient's heart. In one embodiment, a diode is disposed from the emitter to the collector of a pacemaker output transistor to offset the unsymmetrical conduction of the output transistor. In another embodiment, a capacitor of a value presenting an effective short circuit to the frequencies of interest, is inserted across the output transistor to shunt thereabout signals induced by cautery procedures. In addition, the cautery protection circuit includes a suitable inductive element to reduce the high frequency current flow to the pacemaker electrodes to a level below that at which the patient's heart may be excited and further, a capacitor to detune the resonant circuit established by the capacitances of the diodes and the transistor junction, and the inductive element, from the frequencies of interest.