Surgery: light – thermal – and electrical application – Light – thermal – and electrical application – Electrical therapeutic systems
Reexamination Certificate
1999-01-25
2001-12-11
Evanisko, George R. (Department: 3762)
Surgery: light, thermal, and electrical application
Light, thermal, and electrical application
Electrical therapeutic systems
C607S027000
Reexamination Certificate
active
06330474
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to annunciator devices for organ stimulating systems implantable in the body of a patient, and in particular, to such devices which may be used in combination with implantable defibrillator systems, for example, and be assured of attracting the attention of the patient upon the occurrence of a predetermined event. Still more particularly, the invention serves to produce a subaudible vibration which is detectable by the patient.
BACKGROUND OF THE INVENTION
Implantable defibrillation systems are known in the art which deliver a high-voltage defibrillation pulse to the heart when the onset of fibrillation is detected and/or in the event of a detected complete loss of cardiac output. Such known devices are also capable, if the heart exhibits an arrhythmia such as atrial fibrillation, atrial flutter or tachycardia, or ventricular tachycardia, of cardioverting the heart by delivering a high-voltage pulse in an attempt to regain synchronous operation of the heart, instead of delivering the higher voltage defibrillation pulse.
The disclosures of the following patents broadly present the current state of the art with respect to heart monitoring systems.
For example, it is known from U.S. Pat. No. 4,086,916 to contain a cardiac monitoring system in a wristwatch worn by a patient, the system including circuitry for detecting an erratic heartbeat, a missing pulse or other irregularities and providing an alarm indication, audio and visual, when such an event is detected.
It is also known from U.S. Pat. No. 4,088,139 to provide, in an implantable cardiac pacing system, means for generating a marking pulse in the pacemaker monitoring system if an event such as loss of capture occurs. The patient is not immediately informed of the occurrence of such an event, however, the system is provided with telemetry means so that when the recorded data is subsequently read out and examined by a physician, the data will include the marker indicating that loss of capture has occurred. The physician can then take such corrective steps as may be necessary.
An implantable pacing system is disclosed in U.S. Pat. No. 4,102,346 which includes an alarm device as part of the implanted unit which generates an alarm signal to inform the pacemaker user when the battery source of power of the pacemaker is nearing end of life or is malfunctioning.
An implantable tissue stimulating device is disclosed in U.S. Pat. No. 4,345,603 which activates an alarm which informs the patient in whom the system is implanted that the battery is in need of replacement. After the user has been so informed, the user applies a magnet externally in the vicinity of the implanted unit to deactivate the monitoring system and thereby cease the continued operation of the alarm.
A pacemaker for controlling tachycardia is disclosed in U.S. Pat. No. 4,407,289 also disclosing means for informing a pacemaker user of the remaining battery life. The user places a magnet externally in the vicinity of the implanted unit, which thereby causes the implanted unit to generate two pulses which can be seen on the patient's ECG waveform. The time separation between the two pulses indicates the remaining battery potential. Application of the magnet, after the pulses have been generated, temporarily disables the device.
In U.S. Pat. No. 5,190,034, an implantable arrhythmia treatment system is disclosed which includes reliable protection against the release of unneeded treatment pulses, that is, which provides protection against a false-positive output. The disclosed system utilizes an alarm generator which may be disposed in the implanted unit, or in an external unit. The alarm may be of any type which does not require constant, active monitoring by the user, such as a sensory alarm, for example, an audio alarm generator or a tactile alarm generator or “tickler”.
Other examples of implantable arrhythmia devices which include an alarm generator, either audio, tactile, or visual, are found in U.S. Pat. Nos. 4,295,474; 4,210,149; and 3,783,877.
According to the current state of the art, error conditions are announced within an implantable cardioverter defibrillator (ICD) using a piezo annunciator or beeper. Some current implantable devices utilize a piezo actuator to flex the titanium can at audio frequencies. However, the efficacy of audio emissions from devices implanted abdominally can be questioned. The attenuation of the audio transmitted through tissue is dramatic. Aged patients commonly have hearing loss that further decreases their sensitivity to implanted audio generators.
As ICD design targets pectoral implantation, the ICD package dimensions decrease. A current example is the Jewel ™ ICD manufactured and sold by Medtronic Inc. of Minneapolis, Minn. The typical implementation of a piezo annunciator adds to the ICD thickness dimension. The Jewel™ ICD lacks an annunciator. Device malfunction, however, is not announced to the patient until the next scheduled follow-up.
It was in light of the foregoing that the present invention was conceived and has now been reduced to practice.
SUMMARY OF THE INVENTION
According to the invention, an annunciator is provided for an organ stimulating system which is implantable in the body of a patient. A stimulus signal generator such as an implantable cardioverter defibrillator which includes an energizing capacitor is encased in a housing for imparting an electrical stimulation signal to an organ, such as a heart, to be stimulated. The signal generator includes a sensor for sensing at least one of a plurality of physiological characteristics and apparatus for generating an electrical signal corresponding to the sensed physiological characteristic or diagnostic event. A vibration generator responsive to that electrical signal is then operable to impart to the housing a subaudible vibration, that is, one having a frequency less than about 250 hertz, which is detectable by the patient. The vibration generator may include, for example, a motor having an offset mass, a battery for driving the motor with the offset mass to thereby cause the vibrating effect, and a switch responsive to the electrical signal corresponding to the sensed physiological characteristic or diagnostic event for electrically connecting the battery to the motor, energizing the motor, and thereby imparting the subaudible vibration to the housing.
One embodiment of the invention, when applied, for example, to an ICD which utilizes a cylindrical high voltage photoflash-type capacitor for its energization, may be implemented by means of a cylindrical motor having the following attributes:
the motor diameter does not exceed the diameter of the capacitor;
the motor thickness may be typically 6 mm or less;
the motor is packaged within the ICD at one end of a capacitor, effectively adding 1 mm to the length of the capacitor;
the motor contains an offset mass to cause the vibrating effect; and
the motor is directly powered by a typical low-impedance LiSVO (lithium silver vanadium pentoxide) defibrillator battery through an appropriate switching means.
While a motor with an offset mass represents one embodiment of the invention, other acceptable vibration-producing expedients, for purposes of the invention, may be, for example, in one instance, a linear reciprocating motor and, in another instance, a hammer and anvil combination.
It is noteworthy that regardless of the particular manner in which the vibrations are produced, they are of an inaudible quality or nature, intended to be felt, not heard. The pathway for the communication of the vibrations to the patient, therefore, is by stimulating nerves in the skin and/or in the trunk of the body of the patient. The vibrations are not transmitted either through the air or through the patient's skeleton to the ear as would be done were the vibrations within an audible range. In this instance, the vibrations are inaudible, that is, have a frequency of less than about 250 hertz.
The present invention offers numerous advantages. In a first instance, it provides
Evanisko George R.
Pacesetter Inc.
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