Patent ID: 7054688

Claim:
A heart stimulator comprising: a pulse generator which emits stimulation pulses, each having an amplitude; a lead connected to said pulse generator and adapted for introduction into a patient for delivering said stimulation pulses to the patient's heart; a control unit connected to said pulse generator for controlling said pulse generator, in a procedure for determining a stimulation threshold value, to emit stimulation pulses of successively unidirectionally changing amplitudes, and a test pulse following each stimulation pulse, each test pulse having a predetermined high, constant amplitude and being delivered in a refractory period after the preceding stimulation pulse, the amplitude of each test pulse being sufficient to capture a non-refractory heart; a measurement unit connected to said electrode lead for measuring exclusively an amplitude of electrode signals picked up by said lead after each test pulse, as measured signals; and a comparator supplied with said measured signals for comparing the respective amplitudes of said measured signals following each test pulse with each other, and, if a significant change in said amplitude of said measured signals after test pulses occurs, said comparator emitting a signal indicating that the amplitude of the stimulation pulses has passed said stimulation threshold value.