A miniature segment-length strain gauge arch for the assessment of myocardial function

A miniature myocardial segment-length strain gauge arch utilizing solid-state strain gauge elements is described. The arch weighs 0.25 g, has a frequency response flat to 30 Hz, requires simple circuitry, and is stable in situ for periods exceeding 6 hours. Its miniaturization and ease of insertion offer distinct advantages over similar devices previously described. Miniature arches have been applied simultaneously to multiple sites to assess left ventricular function in dogs. The response of these arches to a variety of interventions indicates that this device may be used to follow localized segment-length and velocity changes. The study also clearly demonstrates that the orientation of strain gauge arches with respect to muscle fiber direction in the ventricular wall qualitatively and quantitatively affects the recorded segment-length alterations.