A patch sensor (20, 40) adapted to transmit one or more signals to a medical device, the patch sensor comprising: a transducer array (21, 41) adapted to transmit ultrasound waves and receive echo information to thereby generate a received echo signal; a processing system (22, 42) defining: a first processing pathway (24, 25, 22A) adapted to process the received echo signal to generate a first signal carrying a first type of medical data derived from the received echo signal; and a second processing pathway (24, 25, 22B) adapted to process the received echo signal to generate a second signal carrying a second, different type of medical data derived from the received echo signal, the second signal occupying a greater bandwidth than the first signal; and a communications module (23, 42) adapted to transmit one or more signals to the medical device, the communications module being operable in: a first communication mode, in which the communications module transmits only the first signal to the medical device; and a second communication mode, in which the communications module transmits at least the second signal to the medical device, wherein the first type of medical data is physiological data and the second type of medical data is ultrasound imaging data. a transducer array (21, 41) adapted to transmit ultrasound waves and receive echo information to thereby generate a received echo signal; a processing system (22, 42) defining: a first processing pathway (24, 25, 22A) adapted to process the received echo signal to generate a first signal carrying a first type of medical data derived from the received echo signal; and a second processing pathway (24, 25, 22B) adapted to process the received echo signal to generate a second signal carrying a second, different type of medical data derived from the received echo signal, the second signal occupying a greater bandwidth than the first signal; and a first processing pathway (24, 25, 22A) adapted to process the received echo signal to generate a first signal carrying a first type of medical data derived from the received echo signal; and a second processing pathway (24, 25, 22B) adapted to process the received echo signal to generate a second signal carrying a second, different type of medical data derived from the received echo signal, the second signal occupying a greater bandwidth than the first signal; and a communications module (23, 42) adapted to transmit one or more signals to the medical device, the communications module being operable in: a first communication mode, in which the communications module transmits only the first signal to the medical device; and a second communication mode, in which the communications module transmits at least the second signal to the medical device, wherein the first type of medical data is physiological data and the second type of medical data is ultrasound imaging data. a first communication mode, in which the communications module transmits only the first signal to the medical device; and a second communication mode, in which the communications module transmits at least the second signal to the medical device, wherein the first type of medical data is physiological data and the second type of medical data is ultrasound imaging data.