A medical sensing system (100) includes an elongate interventional device (101) and an adjustable capacitance circuit (102). The elongate interventional device (101) includes a sensor (103) having a capacitance (Css). The elongate interventional device (101) also includes a first electrical conductor (104) and a second electrical conductor (105). The first electrical conductor (104) and the second electrical conductor (105) are in electrical contact with the sensor (103) and extend along the elongate interventional device (101). The elongate interventional device (101) also includes i) an electrically conductive shield (106) that overlaps the electrical conductors (104, 105) and/or ii) an electrically conductive shaft (107). The adjustable capacitance circuit (102) provides an adjustable capacitance (CAdj1, CAdj2) between at least one of the electrical conductors (104, 105) and i) the electrically conductive shield (106) that overlaps the electrical conductors (104, 105) and/or ii) the electrically conductive shaft (107).