[Catheter tip force probe: a paraclinical development for per- and postoperative monitoring in heart surgery]

Local intramyocardial "one-point" force measurement is well adapted to the myocardial architecture. The dense three-dimensional muscle network does not permit direct measurement of longitudinal tension in a particular bundle of muscle fibers. However, measurements on the skeletal muscle have shown changes in tendon stress to be strictly proportional to changes in local force measured simultaneously at different sites on the gastrocnemial muscle. In the heart in situ the response to inotropic and pre- and afterloads changes is extremely sensitive. However, in comparison to left ventricular pressure, local force measurements at different sites and in different ventricular layers show distinct force gradients and phase dislocation, indicating a wide range of inhomogeneities in ventricular dynamics. The method is suitable for clinical application in cardiac surgery: the probe may be implanted directly on the exposed heart or during ventricular catheterization using a pointed catheter tip force probe.