Heart stimulator with evoked response detector and an arrangement for determining the stimulation threshold
First Claim
1. 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.
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Accused Products
Abstract
A heart stimulator has a pulse generator which emits stimulation pulses of different amplitudes, which are delivered to a patient'"'"'s heart via a lead connected to the pulse generator. The pulse generator is controlled by a control unit, in a procedure for determining a stimulation threshold value, to emit stimulation pulses of successively unidirectionally changing amplitudes. Each stimulation pulse is followed by a test pulse having a predetermined high, constant amplitude delivered in a period corresponding to the refractory period after the preceding stimulation pulse. Each test pulse has an amplitude sufficient to capture a non-refractory heart. A measurement unit is connected to the electrode lead, and measures a signal picked up by the lead after each test pulse. The measured signals are supplied to a comparator, which compares the signals following the test pulses with each other. A significant change in the measured signal after the test pulses indicates that the amplitude of the stimulation pulses has passed the threshold value.
25 Citations
8 Claims
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1. A heart stimulator comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification