Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
59 words
An implantable rate responsive pacer provided with adequate means to drive the stimulation/inhibition rate within limits which are programmable and related to the metabolic demand of the patient and including a measurement circuit which detects a parameter strictly dependent on pulmonary minute ventilation, that is the quantity of air inhaled by the patient in the time unit, e.g. liters/min.
Claim 2
Dependent Claim
59 words
An implantable rate responsive pacer provided with adequate means to drive the stimulation/inhibition rate within limits which are programmable and related to the metabolic demand of the patient and including a measurement circuit which detects a parameter strictly dependent on pulmonary minute ventilation, that is the quantity of air inhaled by the patient in the time unit, e.g. liters/min.
Claim 3
Dependent Claim
38 words
The pacer of claim 1 wherein the circuit detecting the patient's minute ventilation includes means to detect variations in time of the geometry of at least a part of the chest of the patient due to pulmonary ventilation.
Claim 4
Dependent Claim
141 words
The pacer of claim 2 wherein said circuit detecting the patient's chest geometric variations due to minute ventilation includes two electrodes (A and B), one of which (B) preferably corresponds to pacemaker (P) conductive case and the other (A) is subcutaneously positioned at an adequate and non critical distance from (B) or is placed on an insulating part (C) of the pacer case, adequate means being provided to detect with the proper sampling frequency, e.g. approx. 10 Hz, the impedance variations in time between said electrodes and other means being provided to process that signal and to produce another signal proportional to minute ventilation, care being taken that said electrode (A) be placed in any position which guarantees that the physiologic variations are very lightly affected by movements other than respiration, for example by the movement of the patient's upper limbs.
Claim 5
Dependent Claim
144 words
The pacer according to claim 3, wherein the physiologic variable processing and detecting circuit comprises in series: - a strobed Impedance/Voltage convertor (1) characterized by minimum energy consumption and producing a signal V ( ZAB ) which corresponds to the impedance detected between the electrodes (A and B) provided with the pacer; - block (2) calculating the absolute value variations between a pulse and the previous one produced by the previous block and producing a signal V' (ΔZ AB ); - a low-pass filter (3) or similar circuit with a time constant of a few tens of seconds, e.g. approx. 30 sec., designed to produce the mean value or the average of the absolute values of impedance variations and to produce a signal Vm (ΔZ AB ) changing proportionally to the patient's minute ventilation VE and, hence, strictly dependent on the patient's physical activity.
Claim 6
Dependent Claim
108 words
The pacer according to claim 4, means being provided to send the output signal of low-pass filter(3)to a programmable correlator (4) which via telemetry link associates two values (Vml and Vm2) of the filter output, "a priori" programmed or obtained by two different physical activity levels, with two rate values (fl and f2) of the pacer circuit; said rates defining a possible operational mode of the pacer wherein the stimulation/ /inhibition rate and the time relations of the various operational stages which are sent to the last block (5) of any cardiac pacer, both single and double chambered, depend on the output data of the low-pass filter (3).
Claim 7
Dependent Claim
71 words
A minimum energy consumption electronic circuit which detects a parameter proportional to the patient's minute ventilation suitable to operate artificial organs, such as an artificial heart, or, more generally, to realize implantable or portable, therapeutic or diagnostic devices, wherein the circuit detecting the patient's minute ventilation includes means to detect variations in time of the geometry of at least a part of the chest of the patient due to pulmonary ventilation.
Claim 8
Dependent Claim
71 words
A minimum energy consumption electronic circuit which detects a parameter proportional to the patient's minute ventilation suitable to operate artificial organs, such as an artificial heart, or, more generally, to realize implantable or portable, therapeutic or diagnostic devices, wherein the circuit detecting the patient's minute ventilation includes means to detect variations in time of the geometry of at least a part of the chest of the patient due to pulmonary ventilation.
Claim 9
Dependent Claim
147 words
A circuit according to claim 6 detecting the patient's chest geometric variations due to minute ventilation, including two electrodes (A and B), one of which (B) preferably corresponds to the (P) conductive case of the therapeutic or diagnostic device and the other (A) is subcutaneously positioned at an adequate and non critical distance from (B) or is placed on an insulating part (C) of the said case, the adequate means being provided to detect with the proper sampling frequency, e.g. approx. 10 Hz, the impedance variations in time between said electrodes and other means being provided to process that signal and to produce another signal propor= tional to minute ventilation, care being taken that said electrode (A) be placed in any position which guarantees that the physiologic variations are very lightly affected by movements other than respiration, for example by the movement of the patient's upper limbs.
Claim 10
Dependent Claim
139 words
A circuit according to claim 7, comprising in series: - a strobed Impedance/Voltage convertor (1) characterized by minimum energy consumption and producing a signal V (Z AB ) which corresponds to the impedance detected between the electrodes (A and B) provided with the therapeutic or diagnostic device; - block (2) calculating the absolute value variations between a pulse and the previous one produced by the previous block and producing a signal V' (ΔZ AB ); - a low-pass filter (3) or similar circuit with a time constant of a few tens of seconds, e.g. approx. 30 sec., designed to produce the mean value or the average of the absolute values of impedance variations and to produce a signal Vm (ΔZ AB ) changing proportionally to the patient's minute ventilation VE and, hence, strictly dependent on the patient's physical activity.
Claim 11
Dependent Claim
73 words
A circuit according to claim 8 means being provided to send the output signal of low-pass filter (3) to a programmable correlator (4) which via telemetry link associates two values (Vml and Vm2) of the filter output, "a priori" programmed or obtained by two different physical activity levels, with two rate values (fl and f2) of the device circuit; said rates defining a possible operational mode of the said therapeutic or diagnostic device.