Abstract: A method of diagnosing the heart condition of a living body moving in the water, in which an electrocardiogram recorded by the steps of hermetically contacting electrodes on the skin surface of the body moving under water, detecting an electrocardiac signal by the electrodes, leading the detected electrocardiac signal through lead wires to a wireless transmitter on the living body, remotely receiving the radio electrocardiac signal transmitted from the transmitted by a receiver, and recording the electrocardiogram on the basis of the radio electrocardiac signal received by the receiver.

Abstract: A waterproof electrode assembly with a transmitter for recording an electrocardiogram, in which the electrodes can reliably be attached on the outer surface of a human body due to bonding force of the adherent sheet and the sucking force caused by returning action of a cup-shaped suction disk to its original shape, the electrodes are not separated from the body even during severe exercise in the water, such as swimming. The waterproofness of the electrode assembly is reliable and durable, and the electrocardiogram of the living body during swimming can be efficiently and accurately recorded, no current leakage phenomenon occurs, the entanglement of the cable with legs and arms can be removed.

Abstract: Waterproof electrodes for recording an electrocardiogram, in which one end of a lead wire is inserted from the convex surface side to the concave surface side of a cup-shaped suction disc made of waterproof elastic material into a through hole formed at the center of the disc, an electrode plate connected to the end of the lead wire is put on the concave surface side of the suction disc to close the hole, the contacting portion between the outer peripheral edge portion of the plate and the concave surface of the suction disc and the gap between the periphery of the wire and the convex surface of the suction disc are respectively hermetically sealed by elastic sealing material, and an annular body surface adherent sheet capable of hermetically sticking on the surface of a human body along the concentric circle surrounding the electrode plate is bonded on the concave surface of the disc.