Medical sensing system comprising: an elongate interventional device; and an adjustable capacitance circuit; wherein the elongate interventional device comprises: a sensor having a capacitance (C ss), the sensor being disposed on the elongate interventional device; and a first electrical conductor and a second electrical conductor, the first electrical conductor and the second electrical conductor being in electrical contact with the sensor and extending along the elongate interventional device for providing electrical signals corresponding to signals detected by the sensor; and i) an electrically conductive shield that overlaps the electrical conductors (104, 105) and/ or ii) an electrically conductive shaft; wherein the first electrical conductor and the second electrical conductor each have a stray capacitance (C S104, C S105) to the electrically conductive shield and/ or to the electrically conductive shaft; and wherein the adjustable capacitance circuit is configured to provide an adjustable capacitance (C Adj1, C Adj2) between at least one of the electrical conductors (104, 105) and i) the electrically conductive shield that overlaps the electrical conductors (104, 105) and/ or ii) the electrically conductive shaft; and wherein the adjustable capacitance circuit is configured to control the adjustable capacitance (C Adj1, C Adj2) based on a difference in stray capacitance (C S104 - C S105) measured between each electrical conductor (104, 105) and i) the electrically conductive shield that overlaps the electrical conductors (104, 105) and/ or ii) the electrically conductive shaft. an elongate interventional device; and an adjustable capacitance circuit; wherein the elongate interventional device comprises: a sensor having a capacitance (C ss), the sensor being disposed on the elongate interventional device; and a first electrical conductor and a second electrical conductor, the first electrical conductor and the second electrical conductor being in electrical contact with the sensor and extending along the elongate interventional device for providing electrical signals corresponding to signals detected by the sensor; and i) an electrically conductive shield that overlaps the electrical conductors (104, 105) and/ or ii) an electrically conductive shaft; a sensor having a capacitance (C ss), the sensor being disposed on the elongate interventional device; and a first electrical conductor and a second electrical conductor, the first electrical conductor and the second electrical conductor being in electrical contact with the sensor and extending along the elongate interventional device for providing electrical signals corresponding to signals detected by the sensor; and i) an electrically conductive shield that overlaps the electrical conductors (104, 105) and/ or ii) an electrically conductive shaft; i) an electrically conductive shield that overlaps the electrical conductors (104, 105) and/ or ii) an electrically conductive shaft; wherein the first electrical conductor and the second electrical conductor each have a stray capacitance (C S104, C S105) to the electrically conductive shield and/ or to the electrically conductive shaft; and wherein the adjustable capacitance circuit is configured to provide an adjustable capacitance (C Adj1, C Adj2) between at least one of the electrical conductors (104, 105) and i) the electrically conductive shield that overlaps the electrical conductors (104, 105) and/ or ii) the electrically conductive shaft; and wherein the adjustable capacitance circuit is configured to control the adjustable capacitance (C Adj1, C Adj2) based on a difference in stray capacitance (C S104 - C S105) measured between each electrical conductor (104, 105) and i) the electrically conductive shield that overlaps the electrical conductors (104, 105) and/ or ii) the electrically conductive shaft.