Myocardium wall thickness transducer and measuring method

US3971363A · kind A · utility

Inventors

• James C. Administrator of the National Aeronautics and Space Fletcher
• Cyril Feldstein · Sierra Madre, US
• Gilbert W. Lewis · Arcadia, US
• Robert H. Silver · San Fernando, US
• Virgil H. Culler · Tustin, US

Key dates

• Filing date: May 5, 1975
• Grant date: Jul 27, 1976
• Expiry date: May 5, 1995

Classification

• Technology area (CPC A): Human Necessities
• CPC primary: A61B5/1076
• WIPO field: Medical technology
• WIPO sector: Instruments

Abstract

A myocardium wall thickness measuring transducer comprises a circular beam of high compliance and an elongated spike which extends in the plane in which the beam is disposed. The spike is connected at one point to the beam while a working end of the spike to which a barb is attached, extends through an opening in the beam at a substantially diametrically opposite point. The beam portion, surrounding the opening, is free to move or be displaced relative to the spike. A sensitive strain gauge is bonded to the beam to sense changes in the tension thereof. The working end of the spike is inserted through the epicardium into the myocardium so that the spike and the beam are in a plane substantially perpendicular to the epicardium at the point of insertion. The spike is inserted, to a depth at which a minimal beam deforming force is applied by the myocardium to the beam portion surrounding the opening. As the heart contracts and myocardium thickness increases larger beam-deforming forces are applied to the beam which increase the beam tension, which is sensed by the strain gauge whose changing output is supplied to an appropriate recorder.