Siemens Aktiengesellschaft

Siemens Elema Ab

Lennart Moberg

Asa Hedin

Anders Lindgren

Jan Ljungstroem

Per Franberg

In a heart stimulator which delivers stimulation pulses to a heart when the heart's spontaneous rate drops below a defined basic rate, in order to reduce the period during which the heart stimulator emits stimulation pulses, the defined basic rate is slow. When the spontaneous heart rate drops below the defined basic rate, stimulation pulses are initially emitted at a faster stimulation rate, in relation to the basic rate, the stimulation rate then dropping toward the defined basic rate.

Heart stimulator

A medical device implantable into the body of a patient with which spontaneous tissue contractions can be detected and tissue contractions can be stimulated, generates a stimulation after the expiration of an adjustable first time interval, started by the respective detection or the stimulation of a tissue contraction, if a spontaneous tissue contraction is not detected before the expiration of the first time interval and if a shorter, second time interval, started by the detection or stimulation of a tissue contraction, has not yet expired. Detection of a spontaneous tissue contraction during the second time interval starts a new second time interval. The duration of the second time interval is automatically set such that it is always shorter by a defined amount than the duration of the first time interval.

Method and implantable medical device for stimulating tissue contractions

A heart pacemaker normally operates at a basic pacing rate having a basic escape interval between pacing pulses associated therewith, so that the pulses are delivered at the basic rate in the absence of a sensed, pacer inhibiting heart event. The pacemaker includes circuitry for setting a hysteresis interval, added to the basic escape interval, to form an extended escape interval in response to the sensed, pacer inhibiting heart event, with the hysteresis interval being a function of the basic escape interval length.

Heart pacemaker with hysteresis function

A method of finding rate responsive parameter settings in a functional relationship between sensor signal and stimulation frequency for a pacemaker by selecting desired heart rates optimal for a patient with respect to certain work loads. The respectively corresponding sensor signal values are obtained from the sensor, and the parameters are calculated by inserting the sensor signal values and selected frequencies into the functional relationship.

Method for finding the parameters in a functional relationship between

A battery test circuit for a heart pacemaker has a stimulation pulse counter and input logic which identify the consumed charge from the operating values of the pacemaker, from the number of stimulation pulses emitted, and from a time-dependent base value. The consumed charge identified in each test is summed in a charge counter. The content of the charge counter is accordingly a measure for the total charge consumed.

Battery test circuit for a heart pacemaker

A battery test circuit for a heart pacemaker generates a signal which corresponds to the charge status of the pacemaker battery which is displayable in a manner which does not interfere with the normal pacing frequency of the pacemaker. A marking pulse is generated by the circuit at a chronological position between successive stimulation pulses which is dependent upon the charge status of the battery at the time the marking pulse is generated.

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Spanga, Sweden

Lennart Moberg