A device for detecting and transmitting electrical pulses from the body surface of a patient to device processing the electrical pulses. The device for detecting includes at least two electrical leads of different lengths, at least one electrical insulating material surrounding the at least two electrical leads, a connecting port for connection to the device for processing the electrical pulses at one end of the at least two electrical leads and a recess in the electrical insulating material of the at least two electrical leads, so that an electric contact can be established with the skin surface of the patient. The two leads of different lengths have a ratio of the electrical resistance to the length of the leads and/or the ratio of the impedance to the length of the leads that is/are greater in the shorter lead than in the longer lead. With the construction artifacts caused by external sources of interference are easily filtered out and it can be manufactured at a low cost, so as to be employed for disposable use.