A method of refining steel utilizing induction melting furnaces sized for use in micro mills consists of charging a medium frequency induction melting furnace having a maximum production rate of about 50 tons per hour with pre-refined steel, and melting steel in the furnace. The melted steel is transferred to a refining vessel, the refining vessel has a high free board, induction heating and stirring capacity and apparatus for supplying blasts of gas. The refined steel is then transferred to a tundish for a continuous casting operation.

Presently, steel scrap is taken from major industrial areas, shipped to remote sites, melted in arc furnaces, either refined in the arc furnace or a ladle metallurgy station and then direct cast into ingots, billets or slabs. The ingot, billets or slabs are then shaped into various end products by conventional rolling or casting means. Additionally, work is being done to develop casters which will continuously cast such end products as rods, wires, sheets and slabs.
Heretofore, the steel industry has used ladle "arc" refining technology as a method for optimizing and increasing the flexibility of the steel production process. The state of ladle "arc" refining furnace technology is set forth in an article by R. J. Fruehan, Professor and Director of CISR, Carnegie-Mellon University, entitled "Ladle Refining Furnaces for the Steel Industry", a report prepared for the Center of Metals Production, in March 1985. In the article, ladle furnaces are described as "not unlike electric arc furnaces", Supra, page 2. Furthermore, the report notes that ladle "arc" furnaces typically range in size from 30-60 tons (a small unit) to 180-240 tons (a large unit). Supra, page 2. The report also notes that it is known to use induction stirring techniques in such ladle "arc" refining furnaces. Supra, Table 4.1.
Induction melting furnaces have been used by the steel foundry industry for approximately 20 years. For example, see the article by R. Duncan entitled "Coreless Induction Melting in Steel Foundries" written for Castell Technical Service of Lopez, Wash. But their application has been limited because at production rates of 100 tons per hour or higher, the furnaces have not proven successful because of their use of 60 cycle current induction technology.
Conventional steel making practice relies on the oxygen decarburization reaction to accomplish refining of the steel scrap or reduce iron used as the charge materials in the melt operation. The decarburization process is characterized by the addition of sufficient carbon during melt or subsequent to melting and then removing the carbon by use of either solid oxygen in the form of scale or ore, or by gaseous injection through lances or other means to achieve a rapid and violent boil. The benefits of carbon are first to lower the melting point of the solid mass thereby reducing the energy to form a molten pool, and second to refine by the generation of carbon monoxide which bubbles through the liquid steel causing the boil. Because most melting processes are relatively slow and usually carried out in air, such as electric arc melting, line frequency or 60 cycle coreless induction, oxidation of the raw materials in the furnace before they turn into liquid is quite prevalent and is another reason for the requirement of the carbon oxygen decarburization reaction.
Another reason for the need of a carbon boil is the increase in the quantities of hydrogen and nitrogen to the liquid steel caused by atmospheric conditions during a slow melting or the action of the electric arc and electric arc melting which ionizes these gases that are then absorbed by the melt. The decarburization reaction flushes excesses of these gases from the melt to tolerable levels.
The action of the arc in the electric arc melting of steel, the slowness and unfavorable melting characteristics of line or 60 cycle frequency coreless induction furnces, and the lack of sufficient power capabilities of the early and non-solid state medium frequency coreless induction furnces made it necessary to rely on the carbon oxygen reaction to form gas bubbles for refining steel prior to the instant invention.
Prior to the instant invention, steel production at micro mill rates, disclosed hereinafter, were either not capable of being produced economically or else required processing methods such as the carburization/decarburization action in order to be economically viable.


A composition is disclosed for freshening sinus cavities, including a carrier of the ingredients and a masking agent for concealing or eliminating odors that emanate from the sinus cavities. The disclosure is also related to a composition for cleansing and freshening nostrils and sinus cavities that includes a saline solution as a moisturizing base component, a flavoring agent, a preservative, an antiseptic and/or anti-microbial agent, a counter-irritant, and an alcohol. The disclosure is also related to the use of such composition to provide many unexpected benefits of clean and healthy nasal and sinus passages.

This invention relates to a composition that is applied to a person""s nostrils and sinus cavities, using an inhaler or other suitable means, for cleansing, freshening and deodorizing the named areas for controlling halitosis.
Conventional control of halitosis or xe2x80x9cbad breathxe2x80x9d, as it is often termed, is presently accomplished through the use of mouthwashes, breath mints, candy, chewing gum, brushing and flossing teeth, and other such means that are taken by mouth. Recent developments in this field have focused on the theory that the digestive organs can be responsible for objectionable odors that are produced from consuming certain foods or liquids.
Many problems have been associated with inadequate cleansing of the nasal and sinus cavities. For examples, smokers of cigars and cigarettes often have a particular form of fetid breath known as xe2x80x9csmoker""s breath.xe2x80x9d Further, other individuals suffering from problems associated with the nasal passages and sinus cavities become addicted to over-the-counter medicated nasal and sinus sprays. Active ingredients in these sprays alter normal body functions in order to achieve short-term results. Prolonged use of medicated sprays frequently results in user dependency. In many cases this occurs long after the original symptoms for which the sprays were intended have run their course.
Additionally, a particular type of fetid breath originates in an area deep within the throat, near the extreme rear of the tongue, where the sphenoid sinus drains into the throat. Bacteria buildup in this area produces sulfurous gases which results in accumulative fetid breath. Small plastic devices, described as tongue scrapers, are a common method people often use in an attempt to dislodge the bacterial build up as they attempt to combat this type of fetid breath; however, many of the users of these devices report vexatious retching with foreign objects placed so deeply within the throat.
Further, some individuals living in harsh, cold climates often associated with mountainous living, reported they frequently experience cracking and bleeding of the nasal passages. These same individuals reported their home interior heating is often very dry, resulting in a mild form of sleep distress.
Individuals living in certain parts of the country such as farm belts and urban suburbs frequently must contend with very high pollen concentrations contaminating the atmosphere. This environmental condition often results in distressed breathing among a great number of people because their airways become heavily taxed when the pollen, which resembles a very fine dust, becomes entrapped in their nose and sinuses. The pollen also results in sneezing and watery eyes.
Certain geographic areas, such as large, industrialized cities have very poor air quality due to high concentrations of airborne pollution caused by industrial and engine emissions, as well as common mold spores, dust and other hazardous particulates. The pollutants can lodge or even clog the nasal passages and sinus, possibly leading to infection.
Another problem associated with the sinuses is sinusitis, an infection of one or more of the sinus cavities, caused by fungus. Once infected, the lining of the sinus cavity becomes swollen, causing a buildup of fluid or mucus. This buildup is responsible for symptoms such as congestion, runny nose, headache pain and sinus pressure.
Not to be confused with chronic sleep disorders, some individuals snore due to obstructed nasal passages. The individuals who exhibit this condition also frequently experience an extreme dryness in their mouth. Much the same as with individuals seeking relief from snoring due to obstructed nasal passages, many other individuals have difficulty sleeping for the same reason xe2x80x9cobstructed nasal passagesxe2x80x9d.
A further possible problem with nasal and sinus passages is associated with the xe2x80x9ccommon coldxe2x80x9d, a minor respiratory illnesses caused by a variety of different respiratory viruses. Symptoms of nasal discharge, nasal congestion and sneezing are usually present from the first day and usually progress to maximum severity by the second or third day. The cost of treatment with over-the-counter medications and outpatient clinics is estimated at more than $6.5 billion annually, all related to the relief of symptoms. The symptomatic treatment available often contains one or more antihistamines, decongestants, antitussives and expectorants, as well as other types of pharmaceutical actives. For individuals with certain medical conditions such as heart disease, hypertension, diabetes or thyroid disorder, these active ingredients could pose a risk.
In a wide range of respiratory infections, increased nasal secretion of mucus greatly reduces the efficiency of the sense of smell and taste, and also frequently creates the sensation of unusual taste and smell. This is sometimes reported as a xe2x80x9cmetallic effectxe2x80x9d. A heavy cold has a similar effect of damping odor sensitivity by the over-production of mucus and the swelling of the nasal membranes. A specific infection of the olfactory membrane, known as rhinitis, may result in an altered or total, temporary loss of smell. The same effect may stem from a number of allergies, all of which are associated with nasal congestion.
Other individuals having problems with nasal and sinus passages are those recovering from post operative medical care that are frequently required to visit an ear, nose and throat specialist (ENT) for sinus and nasal irrigation procedures. In these procedures, solutions are forced, under pressure, into the patient""s affected areas for cleansing.
Some individuals who are required to communicate extensively, such as sales people and teachers, frequently experience excessive dryness of the mouth and nose. This dryness often results in unusual bad breath, as well as a soreness and discomfort of the throat.
Further, an altered sensitivity to odors is commonly encountered during pregnancy. Substances previously pleasant smelling may become repugnant to expectant mothers. The exact reason for this condition is not known, but the body""s changed hormonal state exerts an influence on the olfactory membrane, frequently causing it to swell. Additionally, nasal blockage is commonly associated with pregnancy.
In today""s market place, one can find health care products related to every conceivable hygienic purpose except for the nose and sinuses. For existing oral care products, what are often marketed as xe2x80x9cnew and improved formulasxe2x80x9d are actually nothing more than old concepts. Mouthwash rinses are used to flush the mouth with bacteria killing agents and, in most cases, with additives of various types designed to freshen the mouth and mask odors. Bacterial elimination is normally accomplished by the use of alcohol and/or various dilutions of saline solution. The use of alcohol in these products often causes the intrusive effect experienced by many persons as a burning sensation. Saline solutions are very effective bacteria killing agents and do not cause the burning sensation; however, the taste is not well received by most consumers. While somewhat effective in some cases, mouthwashes and other oral means of controlling breath odors may not be completely effective in solving many of the problems noted above.
It is, therefore, one of the principal objects of the present invention to freshen breath and eliminate or mask objectionable breath odors by introducing the composition of the present invention into the nostrils and therethrough, into the sinus cavities.
Another object of the present invention is to provide a composition which may be conveniently introduced through the nose with, for example, an inhaler or atomizer-type container and which causes no discomfort to the user. A further object of the present invention is to provide an effective means of breath odor control as a substitute or supplement to conventional therapies and which has both immediate and residual effect.
These and additional objects are attained by the present invention which, in the broadest sense, comprises a carrier means, such as water or a dilute saline solution, and an odor masking agent. The odor-masking agent can be an essential oil or flavoring means such as those used in conventional mouthwashes. Other additives may include a small quantity of alcohol for acting on bacteria and an adherent means such as glycerin for maintaining the composition in place in the nostrils and sinus cavities for a sufficient length of time to produce the desired effect. Other means such as preserving agents and healing and soothing agents may also be employed.
Various additional objects and advantages of the present invention will become apparent from the following detailed description.
The present invention is a liquid composition that is inhaled through the nostrils and into the sinus cavities. It is of particular utility for use by persons who smoke cigarettes, cigars and the like, as the smoke necessarily invades the nostrils and sinus cavities when it is inhaled.
The composition includes a carrier means, which can be water or a mild or dilute saline solution. The saline solution is preferred and provides a mild antibacterial effect. Saline solutions are also commonly used as moisturizers at present and are safely used in the nasal passages and sinuses. While the concentration may vary between approximately 50% and approximately 75%, a solution of approximately 65% saline has been found to be effective and non-objectionable for the user.
Control and/or elimination of objectionable odors is accomplished using masking agents in the composition, such as, for example, but not limited to, oil of peppermint, spearmint, etc., or agents having a fruity or citrus essence. Other agents include, but are not limited to eucalyptol, methyl salicylate, and various other flavoring means.
A small quantity of alcohol may be used in the composition to provide an antibacterial effect. The alcohol is not necessary, but may facilitate mixing of the other components. A further component which may be added is a preserving agent such as benzalkonium chloride, which is used to extend shelf life. The use of the preserving agent or agents depends on whether or not some or any of the other components are stable in storage.
It is known in the art that zinc ions are powerful and natural antirhinoviral agents, immune system aids, interferon inducers, cell plasma/membrane pore closing agents, anti-inflammatory agents, antioxidants, protease inhibitors, and strong drying agents. It has been found that zinc ion availability (ZIA) values of approximately 100 will shorten the common cold by an average of seven days. Prior to the composition of present invention, ZIA 100 was only available in the form of zinc acetate lozenges. The composition of the present invention can also incorporate the ZIA 100 zinc acetate, or zinc chloride, thereby providing further healing and soothing properties to the composition. The zinc acetate or zinc chloride provided in the composition is pleasant tasting, flavor stable and causes no objectionable after taste.
Also included in the composition is an antiseptic and/or anti-microbial agent. Various embodiments of the composition exist in which various antiseptic and/or anti-microbial agents are used. In the preferred embodiment of the composition, the antiseptic agent used is cetylpyridinium chloride (CPC). Other antiseptic and/or anti-microbial agents include, but are not limited to, chlorhexidine digluconate, hexetidine, sanguinanine, triclosan, and benzalkoniun chloride. It should be understood that many other antiseptic and/or anti-microbial agents could be used in the present invention, as would be known to one skilled in the art.
The delivery method used for the composition can vary. Delivery means of the composition include for example, but are not limited to, spray bottles, droppers, and/or atomizer-type squeeze or pump bottles. Experimentation with a one ounce (1 oz.) pump atomizer spray bottle can be an effective delivery means of the composition. Containers of this type are currently used by several pharmaceutical companies for introducing sinus medication into the nostrils and sinus cavities. The atomizer-type bottles reduce the composition to a very fine mist, thus making the delivery of the composition minimally intrusive.
No discomfort for the user was experienced in testing of the composition. In addition, no harmful effects on the nostrils or sinus cavities were caused by any of the components of the composition. Further illustrated by clinicals entitled: xe2x80x9cA Phase Study to Evaluate the Safety and Efficacy of SinoFresh Nasal Care Used Twice Dailyxe2x80x9d (the Study). The composition effectively eliminated or masked odors associated with smoking and with eating various foods such as onion, garlic and other spices, as well as certain liquids, particularly alcoholic beverages, coffee, tea, etc.
There are numerous advantages and unexpected results from use of the composition. For example, smokers and those exposed to second hand tobacco smoke who routinely use the composition of the present invention have all reported the complete elimination of smoker""s breath. Many have also reported an improvement in their sense of smell after prolonged use of the composition.
Other than being the location of the olfactory membrane, the nasal cavity is quite unrelated to smells and smelling, but instead acts as an air-conditioning type system to clean and treat the air breathed before the air meets the sensitive and delicate tissues of the lungs. As such, it has been found unexpectedly that the sense of smell is improved by the cleansing of the olfactory hairs and the replacement of olfactory mucosa while using the composition of the present invention. Also, nose hairs become burdened with nicotine, tar and other tobacco-related chemicals. Routine hygienic cleansing of the nasal passages and sinus cavities aids the body in ridding itself of offensive odors, especially those that have become trapped in the middle, inferior and superior nasal concha. Freshening ingredients of the composition of the present invention that are left in the nose after cleansing with the composition leaves the nose and sinuses feeling cleansed, cleared, and refreshed with a minty aftertaste.
Many people have been able to substitute the use of the composition of the present invention in lieu of use of the medicated sprays, thereby relieving their dependency. Their unexpected results can be explained in several ways. First, the user develops a habit with regard to the sprayer itself. For example, some reformed smokers utilize a therapeutic device resembling a cigarette to imitate the act of placing an actual cigarette in their mouth. The use of the present composition fulfills a similar function for the user as use of stronger, harsher medicated sprays. Second, by keeping nasal passages and sinuses cleaner and therapeutically refreshed, users experience increased breathing capacity. This is especially beneficial because it is accomplished without the use of medicated ingredients. Therefore, the composition can be used as often as desired with absolutely no addictive problems.
Some individuals who use the composition have reported an unexpected improvement in oral-related fetid breath. Prolonged use of the composition allows for residual deposits of the cleansing and freshening agents to pass through the nasal and sinus passage and drain down into the described area of the mouth, thus resulting in correlative improvements in reducing these bacteria and deposits, and leaving behind freshening agents. The composition offers a more user-friendly approach to this type of bad breath.
While using the composition individuals living in harsh, cold climates that experience cracking and bleeding of the nasal passages reported a heretofore unprecedented tremendous improvement in the cracking and bleeding symptoms, as well as improvements in their sleep distress. These improvements are a result of moisturizing agents and isotonic saline nature of the composition ingredients. The sleep distress is relieved with a clearing of the nasal passages, which makes breathing easier in the thin atmosphere.
It is found unexpectedly that, with respect to those individuals living in areas with a high pollen count, routine hygienic cleansing of the nasal passages and sinuses with the composition, loosens and expels much of the pollen that has become trapped in the nasal passages and nose hairs which are acting as the body""s filtering system for the respiratory system. The more the composition is used, the more pollen that is expelled. Because there are no medicinal ingredients in the composition, the user can cleanse the nose as often as necessary in order to relieve this type of problem.
For individuals living in polluted geographic areas, routine use of the composition can provide a previously unknown innocuous method of expelling much airborne pollution from the nose and sinuses. Use of the composition results in a cleansing and freshening process that improves breathing ability.
With respect to sinusitis, clinical studies were conducted to validate the use of the composition in the prevention and treatment of chronic sinusitis, the basis of which is the antifungal properties of the solution. In addition, it has been found unexpectedly that routine use will relieve many of the symptoms and bathe the affected area with soothing and antibacterial, anti-fungal, and/or anti-infective ingredients. Fetid breath is often present as an additional symptom of sinusitis that use of the composition can, in most cases, eliminate. Further illustrated by Clinicals entitled xe2x80x9cIntranasal Antiseptic Effect on Chronic Sinusitis Protocolxe2x80x9d.
Individuals who snore, that regularly maintain good hygienic practices by utilizing the composition just prior to retiring to bed, report an unexpected and significant change in their ability to breathe clearly through the nose. With their change in breathing, they reported a decrease in oral dryness, thereby relieving the condition that is known to cause snoring.
The composition is also useful with resolving problems associated with the common cold. While the composition is not a cure for the common cold, many of the symptoms can be relieved without the need for medical or pharmaceutical ingredients. While the cold is xe2x80x9crunning its coursexe2x80x9d, keeping the nose and sinuses clean, bathed and refreshed with minty, freshening ingredients helps the individual feel and breathe much better. Engaging in a thorough hygienic cleansing just prior to retiring for bed and after arising, thereby expelling excess nasal and sinus mucus that cause a xe2x80x9crunny nosexe2x80x9d, brings tremendous relief to the user. Further, as noted previously, by raising the ZIA values in individuals suffering from the outset of a cold, the composition can shorten the duration of the cold.
For those individuals suffering from difficult breathing during sleep, many users of the composition have reported, unexpectedly, that they breathe much better after a thorough, hygienic cleansing of the nose and sinuses just prior to retiring to bed. Nasal mucus and other related foreign matter that has accumulated in the nose hairs is easily expelled with the therapeutic process. The user retires with clearer nasal passages and a refreshed, minty aftertaste and is less likely to experience sleep disorders associated with blocked nasal passages.
Further, within the scope of their ENT""s complete approval, some of the users of the composition have utilized a method of hygienic cleansing of the nose and sinuses to compliment the care received at the ENT""s office after surgery on the nose and/or sinus passages. The ingredients contained in the composition are completely innocuous, i.e., there is nothing present that will interfere with the physician""s care. Unexpectedly, these users reported their breathing became easier, their nose and sinuses felt cleaner and very positive changes occurred in what they described as xe2x80x9cvery fetidxe2x80x9d breath. The composition cannot be substituted for an ENT""s care and hygienic cleansing of the nose and sinuses cannot be compared to, nor achieve the same results, as physician-supervised irrigation, no more than toothpaste and mouthwash can be substituted for procedures performed by a dentist in their office; nonetheless, the invention provides advantages to the user that do not come without its use.
With regard to individuals whose occupations require extensive verbal communication, unexpected results indicate that users of the composition have been able to restore moistness to their noses and sinuses and during routine use, residual amounts of the ingredients pass through the nose and sinuses, leaving deposits of the cleansing, freshening agents to soothe the throat.
With respect to pregnant women, users of the composition with this condition described as hormonal change have reported that routine cleansing of the nasal passage and sinuses seemed to improve their ability to breathe, likely due to the expulsion of the nasal blockage in the form of excess nasal mucus. The freshening ingredients left behind results in a minty aftertaste which can also often replace the sense of repugnant odors that may come with pregnancy.
The composition is truly an exception since it is in fact a new concept in the control of fetid breath. Prior to the invention, the effect the nose and sinuses have on a person""s breath was not addressed. In addition, few people have considered the positive health benefits that can be achieved with routine therapeutic cleansing of the nose and sinuses.
If one examines an air filter, taken from the average home interior heating and cooling system, the debris caught in the filter clearly reflects samples of the many contaminants we ingest into our noses on a daily basis. If these filters were never cleaned, eventually the system would shut down. Because the nose and sinuses provide a similar function for our respiratory system, the positive benefits that can be achieved by routine cleansing is apparent.
The routine, hygienic cleansing of the nose and sinuses, using the composition containing isotonic saline, moisturizing, purifying and antiseptic agents will result in cleaner, healthier nasal and sinus passages, rewarding the user with an improved breathing ability. Unexpected results reveal that users of the composition have reported relief of many types of symptoms, likely due to their routine programs of hygienic cleansing of the nose and sinuses. After thorough cleansing, the deposits of freshening ingredients left behind replaces the metallic effect with a minty aftertaste.

Composition for freshening nostrils and sinus cavities


The present invention provides a storage means to store digital data entries, chronometer means arranged to provide chronological information to the device, and data entry arrangement means to manipulate data entries, wherein the data entry arrangement means is configured to utilize the chronometer means to provide a chronological data entry coding to data entries based on the chronological sequence in which the data entry is stored on and accessed from the data storage means, and wherein the data entry arrangement means is further configured to analyze the data entry chronological data coding and based on the coding, compress the data entry during a data entry compression cycle.

1. Field of the Invention
The invention relates to a digital device configured to store, and provide access to, data entries based on considering data entry chronology (age) and usage. It also relates more generally, to a method of storing, and providing access to, digital data entries based on considering data entry chronology and usage.
2. Description of the Prior Art
Information is becoming increasingly available and being provided for use with digital devices. For example, computers connected to the internet have access to a large volume of information, much of which can be stored on the computer. In the case of the emerging mobile society, increasing travel has resulted in an increased number of information sources available to individuals, for example, information derived from day to day business and/or social activities. Each of these sources generate information which can conveniently be stored on portable digital devices such as laptop/palmtop computers and mobile phones.
It is increasingly possible to have affordable large capacity digital storage devices. In addition, it is also possible to have relatively small sized digital devices which have comparatively large memory capacities compared to equivalent sized devices of a few years ago. Nevertheless, the storage medium used by digital devices have a finite storage capacity, which can be increasingly filled with the wealth of information which is becoming available. Solutions are required to allow more information to be stored on smaller devices and thus address the issue of the finite capacity of storage media.
Solutions exist which effectively provide more available space for a given finite capacity storage device by compressing the data on the storage device. Thus, the data occupies comparatively less space on the storage media, leaving more available space for further data. However, compressed data needs to be de-compressed before it can be accessed, thus resulting in relatively slow data access.
Accordingly, in a first aspect, the present invention provides a digital device comprising data storage means to store digital data entries, chronometer means arranged to provide chronological information to the device, and data entry arrangement means to manipulate data entries, wherein the data entry arrangement means is configured to utilize the chronometer means to provide a chronological data entry coding to data entries based on the chronological sequence in which the data entry is stored on and accessed from the data storage means, and wherein the data entry arrangement means is further configured to analyze the data entry chronological data coding and based on the coding, compress the data entry during a data entry compression cycle.
In the case where the data entry is written to the storage means for the first time, the chronological code corresponds to the date and time on which the entry was made. In the case of subsequent access of the data entry, the chronological code is changed to refer to the subsequent access. During a data entry compression cycle, the data entry arrangement means analyzes one or more data entry chronological codes and determines whether or not (or to what extent) the or each associated data entries should be compressed. So, for example, a data entry which was stored some time ago, and not accessed at all, would have an old chronological data coding and, as such, would be compressed. However, a data entry which has been accessed recently would remain un-compressed and be ready for relatively speedy retrieval.
One way of allowing user access to the data entries is, of course, to arrange the data entry arrangement means to provide the data entries stored on the memory means, based on chronology and usage to a user of the digital device. Accordingly, access of data entries is also be based on data entry chronology and/or usage.
The present invention therefore minimizes the effect of relatively slow data access of compressed data and, at the same time, makes efficient use of the capacity of the data storage means. This is done by configuring the digital device to compress data entries based on data entry chronology and usage that is the invention compresses data based on when the data was accessed and also when it was stored on the storage means.
The data entry compression cycle may occur after a set interval of time, for example, after one day. Of course, the set interval of time may be held fixed or varied over a period of time. An example of the latter case is an initial data entry compression cycle occurring after one day, and the following data entry compression cycle occurring after a further two days. Accordingly, the data arrangement means would be arranged to run a data entry compression cycle after a set interval of time.
However, an effective way of managing the memory capacity of the data storage would be to base the data compression cycle on when the total data, or recent data entries, on the storage means occupy a certain proportion of the capacity of the data storage means, for example 5% of the total capacity of the storage means. Accordingly, the data entry arrangement means is arranged to run the data entry compression cycle when data entries occupy a certain proportion of the capacity of the data storage means.
A single data entry or, alternatively, a number of data entries may be compressed by the data entry arrangement means during a data entry compression cycle. Accordingly, the invention is not limited to compression of data entries occurring in batches.
It is important to note that the invention does not exclude compression of all data entries by default, for example, by the data entry arrangement means being configured to compress all data entries by default. However, upon subsequent use of a data entry, the coding provided to the data entry is changed by the data entry arrangement means and thus, during the next data compression cycle, the data may be compressed to the same, or preferably a differing degree.
In one embodiment, the size of a data entry may be considered in determining whether to compress the data entry. In such a case, the data entry arrangement means may be configured to consider the size of the data entry. So, for example, a large data entry may always be compressed by default whereas a relatively small data entry may be left un-compressed.
The same compression rate may be used for all data entry compressions. However, in an alternative embodiment, the device may be configured to vary the data entry compression rate based on the degree of data entry usage. So, for example, a data entry which has not been used for a while, but when used, was used quite frequently, is not compressed as much as compared with a data entry which wasn""t used that frequently when in usage. If the size of the data entry is also to be taken into consideration, a data entry which occupies a large memory space but which is often used may be compressed to a limited degree, or not at all, whereas a data entry which is hardly used at all, regardless of the size of the data, may be compressed to a relatively high degree. In all such cases, the data entry arrangement means may be configured to utilize a data entry chronological coding designed so as to represent a particular compression rate for a particular chronology/usage. In this way, the invention considers how often data entries have been used and does not just consider when the data entry was last accessed.
It may be that a data entry remains un-used, or is moderately used, between compression cycles. In such cases, the data entry arrangement means may be configured to compress such a data entry to a greater degree during a subsequent data entry compression cycle, which may or may not be the next data entry compression cycle. This process may occur during a number of subsequent data entry compression cycles such that the data entry is progressively compressed to a greater degree.
To further release memory capacity, the digital device may be configured such that a data entry which has not been accessed for a pre-determined period of time, for example 6 months, is removed from the storage means. This may be by means of deletion from the storage means or transfer to an archive on a separate storage means. This separate storage means may be provided on a separate device which may, or may not, have the same configuration of the device of the claimed invention. Accordingly, the invention does not require the user to replenish the capacity of the storage means by wilfully remembering to remove old, unused data entries.
In a further embodiment, the data entry may be removed from the storage means following progressively increasing compression. This may, for example, be once the data entry has been compressed to a maximum, or pre-determined, level due to a lack of usage.
Each data entry may consist of a number of data fields (or portions), and each data field may contain data of differing detail and complexity. For example, in the case of a individual""s personal details, one field would be the individual""s name, another the address, and another a map to provide visual guidance as to where the person lives. One of the data entry fields may also be a sound file. As these fields contain information of varying complexity, they would occupy a corresponding differing amount of memory space when stored on the data storage means. In a further embodiment of the present invention, the data entry arrangement means may be arranged to compress a portion of such a data entry. Preferably, this portion is the portion of the data entry which would occupy a relatively large amount of memory space on the storage means. The compressed portions of the data entry may also be removed from the data entry storage means, as described above, possibly for retrieval later. This is a way of essentially trimming down the data entry over a period of time.
The digital device would preferably be configured to leave a portion of the data entry which allows a user to easily identify the data entry un-compressed, for example a heading/title, as such a data entry field would not occupy a large amount of space. In cases where a data entry does not have a heading or other such field which easily identifies the data entry, the digital device would preferably be configured to allow the user to provide such information.
In a further embodiment, the digital device may be arranged to store data entries of a particular usage and chronology in different areas of the data entry storage means. For example, recent data entries may be stored in a separate area of the storage means compared to old data entries. Data entries of a particular compression rate/ratio may also be stored in separate regions of the storage means. It may be that storage is provided not just in a separate area/region of a storage means, but in separate storage means altogether. This may be achieved by configuring the data arrangement means to use the chronological data code to identify the data entries of differing chronology and usage and thereby determine where the particular data entry should be stored. For example, chronological data entry codes could be devised to indicate specific compression ratios. Accordingly, if the digital device is configured to know that a particular chronological data entry code corresponds to a particular compression ratio, and that all the data entries compressed to the same ratio are located in the same region, knowledge of the location of this region will reduce data entry access time as a search of the entire data storage means would not be required. Such arrangements would also cluster wear and tear to particular areas/regions of one or more storage means.
In another embodiment, the digital device may comprise positioning means which registers where the device is in a particular geographical locality, and the data arrangement means is configured to associate the positional information provided by the positioning means with the chronological data entry codes. The positioning means may provide geographical information at the global or local scale. For example, the positional information may provide information concerning floor level, building level, street level, town level, metropolitan level, country level etc. Such arrangements would be able to identify data entries based not only on chronology and usage, but also on locality. Thus, it is possible to retrieve a data entry based firstly on a particular locality/area and secondly based on chronology and usage, or vice versa. So, for example, a user is able to travel from a first country to a second country and be able to easily access information which the user accessed when they were last in the second country. Similarly, a user could travel at street level, and when arriving at a particular street, easily access information which last accessed when the user was on the same street for example provide a list of items last purchased from a grocery store.
In another embodiment still, the data arrangement means may be arranged to allow user selected data entries to be compressed during a data compression cycle. This allows a user to interact with the device and initiate data entry compression of specific data entries. This may be done, for example, when a user knows that a data entry will not be required for a while. The user may also be able to select a particular compression rate and/or particular portions of a data entry for compression.
In a second aspect, the present invention provides a method of storing digital data comprising providing a data entry chronological coding to a data entry based on the chronological sequence in which the data entry is stored and accessed, analyzing the data entry chronological coding and, based on the coding, compressing the data entry during a compression cycle.
Obviously, the provision of data entries which have been stored by the method are included as an embodiment of the method.
Various embodiments of a digital device have been discussed above which utilize variations to the aforementioned method of storing digital data. Such methods of storing digital data are also within the scope of the invention. For example, the degree of compression may be varied based on chronology and/or usage, data entries may be progressively compressed and ultimately removed. Portions of data entries may also be compressed and removed. Data entries may also be stored, and therefore provided, based on geographical location.

Storage of data entries in digital devices and methods


The present invention concerns an electronic device for generating and displaying an item of information, including a flexible body (2) shaped to be able, for example, to be secured to a user""s wrist, an electronic unit (18) for generating the information, at least a display cell (20) for displaying said information, and an electric power source (22) for powering the electronic unit (18), wherein the flexible body (2) has, at at least one location on its length, an overthickness of material forming a rigid receptacle (28) in the inner cavity of which is arranged said electronic unit (18).

The present invention concerns an electronic device for generating and displaying an item of information.
A device of the aforementioned type essentially includes an electronic unit intended to provide an item of information, a display cell connected to the electronic unit for displaying the information, and an electric power source powering the electronic unit.
A device of this type may constitute, for example, an electronic timepiece with a digital or pseudo-analogue display. In this case, the electronic unit includes a time base circuit formed by an oscillator and a frequency divider, and counters which supply time-related information in response to signals provided by the time base circuit. The display cell is then arranged so as to display this time-related information which generally include at least the hour and minute of the current time. Very often the electronic unit and the display cell are arranged so that the second of the current time is also displayed, as well as other information such as, for example, the date, the day of the week, a measured time or an alarm time.
It will be evident upon reading the following description that the present invention is not limited to the case wherein the device is a timepiece, but that it can be adapted without any difficulty to any case wherein an item of information is generated by an electronic unit is to be displayed by a display cell.
Devices of this type which are known to this date generally include a rigid case, made of metal or plastic, in which are mounted the display cell, the electronic unit and the electric power source which is generally a battery. These elements are joined mechanically by a frame housed in the case, and they are electrically connected by connecting elements.
The case is generally closed by a back cover and a crystal through which the display cell is visible. Finally, manual control members such as, for example, pushbuttons, are often mounted on the case to allow various functions of the device to be controlled, such as the time setting function if the device is a timepiece.
Despite all the simplifications which have been made to the construction and manufacture of such devices, they are still quite complicated and thus are not able to be manufactured at a very low price. Further, the known devices are generally fragile and not water resistant, unless special measures are taken. These special measures of course increase the cost price of these devices.
Finally, these known devices are relatively heavy, in particular when their case is made of metal, and they have a substantial thickness.
In order to overcome these drawbacks, the Applicant has already proposed, in European Patent No. EP 0 138 098, a device of the type defined hereinbefore which is both inexpensive, of small thickness and flexible. This device includes three stacked flexible elements, namely an electronic unit for generating an item of information, a display cell for displaying this item of information, and an electric power source for powering the electronic unit. These three elements are mechanically connected and electrically connected to each other respectively by insulating adhesive materials and conductive adhesive materials.
The display cell is a liquid crystal cell which includes, in a conventional manner, two plates which delimit it and surround the liquid crystal layer. These two plates are formed by thin films of plastic material, for example a polyester or another polymer. Consequently, the cell is very thin, and it has a certain flexibility, which allows it to be deformed without being damaged and without ceasing to operate. Such a cell may have a total thickness of approximately 0.2 mm.
The electric power source is formed by a flat battery which includes a positive plate made of stainless steel, a negative plate made of zinc and an electrolyte, for example zinc perchlorate, contained in a porous separator arranged between the two plates. The plates and the electrolyte of this battery are arranged between two thin sheets of plastic material or cardboard which are welded or bonded to each other at their periphery. As all the components of the battery are very thin, the battery is also very thin. It may have a thickness of less than 1 mm. Such a battery has a certain flexibility and can be deformed without ceasing to operate.
Finally, the electronic unit includes a printed circuit including a flexible insulating substrate on which are deposited conductive paths. The electronic unit further includes an integrated circuit and a piezoelectric resonator. The integrated circuit may be arranged so as to perform, for example, time measuring functions. The electronic unit is very thin. The substrate has a thickness of 0.2 to 0.3 mm, and the integrated circuit and the resonator have thicknesses of approximately 1.5 mm. Since the substrate is flexible, so is the electronic unit.
The display cell is applied against the top face of the electronic unit, and the electric power source is applied against the bottom face of the electronic unit. These three elements are mechanically connected and electrically connected to each other respectively by insulating and conductive adhesive materials. The device thus formed is very thin. As all the elements are flexible and the layers of adhesive are extremely thin, the device is itself flexible and can be deformed without ceasing to operate. One may, for example, give this device the general shape of a wristband and provide, at the ends thereof, clasp means. As a result of the flexibility of the sheets of plastic material and/or cardboard which form this device, it may be worn like a conventional wristwatch.
A portable device including a flexible display cell and a wristband which forms the body of the device is also known from International Patent Application No. WO 99/67702. The wristband allows the device to be secured for example around a person""s wrist. The portable device includes light flexible elements which allow it to match the shape of a given contour and to have a flat profile. The device can undergo the deformations to which a watch, for example, is subjected during normal physical activity, without being damaged. A clasp system made of a flexible polymer material is overmoulded onto the wristband.
The portable device may present information by means of the flexible display cell and a thin flexible piezoelectric loudspeaker. It may receive information via data input keys. The piezoelectric loudspeaker/microphone also allows the device to receive acoustic data. The portable device can communicate with external devices such as a computer or a smartcard reader via a communication element. This communication element may be an inductive loop deposited by screen printing inside the body of the device. The device may include an electric power source such as a flat lithium battery.
More precisely, the portable device includes top and bottom protective layers and spacers. The display cell is coated with a transparent material such as PVC. By molding or machining, the protective layers are given the necessary shape for receiving the internal components. These internal components include an integrated circuit mounted on a flexible printed circuit. The integrated circuit may include a microprocessor. The flexible display cell can be made using different materials. According to one embodiment, transparent electrodes are deposited on the inner faces of the top and bottom protective layers. The electrodes are shaped so as to provide a dot-matrix display or digit display. The display cell is formed of a liquid crystal display film which is a bi-stable or multi-stable material maintaining the displayed image even when the electric power supply is cut.
The microprocessor of the integrated circuit activates a control circuit which supplies the voltages necessary to activate and deactivate the pixels of the display cell. The electric power source arranged inside the portable device or an external power source (for example a smartcard reader) supplies the power necessary for the microprocessor and other elements to operate. The portable device can receive control pulses via data input keys. These keys which are dome-shaped, are laminated between the inner and outer protective layers of the portable device. Regions located directly below the data input keys are laminated inside with a rigid material to increase the reliability of said keys and to improve the reaction to the touch.
The devices of the type described hereinbefore have the particular advantage of being both flexible and of small thickness. Their main drawback lies however in the fact that certain of the components which form them are very fragile. This is true in particular for the integrated circuits which include, in a conventional manner, a silicon plate in which are formed the various electronic components necessary for performing the desired electronic function or functions. These silicon plates are coated with a protective layer generally made of glass. When a device of the aforementioned type constitutes, for example, an electronic timepiece, it further includes a quartz resonator element encapsulated in a ceramic or glass case. These various components are thus rigid and liable to be damaged or to cease operating when the device to which they are fitted is deformed to be able, for example, to be secured to a user""s wrist. The electric connections which connect between them the battery, the integrated circuit, the display cell and the quartz resonator in the event that the device is a timepiece, are also extremely fragile and are liable not to withstand the deformations to which a watch, for example, is subjected during normal physical activity.
The main object of the present invention is thus to overcome the drawbacks of the aforementioned prior art in addition to others by providing an electronic device of the type defined above which is both inexpensive, light, water resistant and especially not fragile.
The present invention thus concerns a device for generating and displaying an item of information including a flexible body which can, for example, be given the shape of a wristband to be able to be secured to a user""s wrist, an electronic unit for generating the information, a display cell for displaying said information, and an electric power source for supplying the electronic unit, characterised in that the flexible body has, at at least one location on its length, an overthickness of material forming a rigid receptacle in the inner cavity of which is arranged said electronic unit.
As a result of these features, the present invention provides an electronic device which is formed solely of a flexible body which can be given, for example, the shape of a wristband which is thicker and more rigid at its middle and flexible and thin towards its ends. Such a flexible body thus fulfils the two conventional functions of a wristwatch which are the protection of the most fragile components and the securing of the watch around its user""s wrist. Indeed, when the device according to the invention constitutes an electronic timepiece, the fragile electronic components such as the integrated circuit, the quartz resonator element or even the battery which form it are housed in the thick portion of the flexible body which they contribute to making more rigid. These components are thus sheltered from dust, water or humidity, and can withstand the mechanical stress to which the flexible body is subjected when it is deformed to be able to fit a given profile without being damaged or ceasing to operate. Likewise, the problem of the electric connections which connect between them the components described above is also resolved insofar as these components and the conductive paths which connect them are arranged in the rigid volume of the flexible body. A reliable electric connection is thus obtained between the different components which constitute the device according to the invention.
According to another feature, the electric power source is also arranged in the rigid receptacle.
According to another feature of the invention, the flexible body includes in succession a flexible reinforcing layer forming the bottom of the electronic device, in which is arranged the receptacle intended to accommodate the electronic unit and the electric power source, a flexible printed circuit having a bottom face and a top face respectively turned towards the reinforcing layer and towards the top of the electronic device, the electronic unit and the electric power source being secured to the bottom face of the flexible printed circuit, while the display cell is arranged on the top face of said flexible printed circuit, and a flexible protective layer covering the flexible printed circuit.
Thus, the present invention has the form of a strip of very small thickness at one location on the length of which there is an overthickness forming a rigid cavity in the volume of which are housed the fragile electronic components. The entire length of the strip can thus be used for the display of information or decorative patterns which may change if required.

Electronic device for generating and displaying an item of information


A token calculates a one time password by generating a HMAC-SHA-1 value based upon a key K and a counter value C, truncating the generated HMAC-SHA-1 value modulo 10^Digit, where Digit is the number of digits in the one time password. The one time password can be validated by a validation server that calculates its own version of the password using K and its own counter value C′. If there is an initial mismatch, the validation server compensate for a lack of synchronization between counters C and C′ within a look-ahead window, whose size can be set by a parameter s.

Today, deployment of two-factor authentication remains extremely limited in scope and scale. Despite increasingly higher levels of threats and attacks, most Internet applications still rely on weak authentication schemes for policing user access. The lack of interoperability among hardware and software technology vendors has been a limiting factor in the adoption of two-factor authentication technology. In particular, hardware and software components are often tightly coupled through proprietary technology, resulting in high cost solutions, poor adoption and limited innovation.
In the last two years, the rapid rise of network threats has exposed the inadequacies of static passwords as the primary mean of authentication on the Internet. At the same time, the current approach that requires an end-user to carry an expensive, single-function device that is only used to authenticate to the network is clearly not the right answer. For two factor authentication to propagate on the Internet, it will have to be embedded in more flexible devices that can work across a wide range of applications.
One Time Password is certainly one of the simplest and most popular forms of two-factor authentication for securing network access. For example, in large enterprises, Virtual Private Network access often requires the use of One Time Password tokens for remote user authentication. One Time Passwords are often preferred to stronger forms of authentication such as PKI or biometrics because an air-gap device does not require the installation of any client desktop software on the user machine, therefore allowing them to roam across multiple machines including home computers, kiosks and personal digital assistants.


A single-pass pacing and/or shocking lead system is capable of sensing cardiac signal in the atrium and the ventricle in a xe2x80x9cbipolar fashionxe2x80x9d using a three-electrode structure: a first electrode in the atruim, a second electrode in the ventricle just below the tricuspid valve, and a third in the ventricle.

The invention generally relates to implantable stimulation devices such as cardiac stimulation devices, cardioverters and defibrillators. More particularly, this invention relates to an implantable stimulation system having a single-pass lead which delivers stimulation therapy and is capable of a plurality of programmable sensing polarities, including bipolar atrial and ventricular sensing with respect to an electrode positioned near the tricuspid valve.
Implantable stimulation devices, such as cardiac stimulation devices and implantable cardioverter-defibrillators (hereinafter referred to as ICDs), are often used to remedy improper heart function. These devices generally provide an electrical pulse to a selected area of the heart that is not (in terms of timing or strength) adequately receiving its natural pulse. Under abnormal cardiac conditions, and particularly cardiac rhythm disturbances, stimulation therapy is applied to remedy several forms of cardiac arrhythmias (rhythm disturbances) including bradycardias, AV conduction block, supraventricular tachycardias, and atrial and ventricular ectopic arrhythmias.
There are essentially two kinds of stimulation devices: single-chamber and dual-chamber. Single-chamber stimulation devices are capable of sensing and pacing in only one of the atrium or the ventricle. Dual-chamber stimulation devices are capable of sensing and pacing in both the atrium and the ventricle. There are many modes of dual-chamber pacing such as VDD (paces in the ventricle only, senses in the atrium and ventricle), DVI (paces in the atrium and ventricle, and senses in the ventricle only), DDI (senses and paces in both the atrium and ventricle), and DDD (senses and paces in both the atrium and ventricle, with an inhibited and triggered response to sensing).
A letter xe2x80x9cRxe2x80x9d is sometimes added to these stimulation device modes to indicate the stimulation device""s ability to provide rate-modulated (also sometimes called rate-responsive or rate-adaptive) pacing in response to input from an independent sensor. For instance, a DDDR stimulation device is capable of adapting to the need to increase a patient""s heart rate in response to physiologic stress in the absence of intrinsic response from a patient""s sinus node.
Dual-chamber ICDs are also known in the art to proved pacing, cardioversion and defibrillation therapy in both chambers of the heart.
A stimulation device uses a lead system to perform its sensing and stimulation functions. A lead system typically comprises at least one lead, one or more conductor coils, and one or more electrodes. The lead is the insulated wire used to connect the pulse generator of a stimulation device to the cardiac tissue. The lead carries the output stimulus from the pulse generator to the heart and, in demand modes, relays intrinsic cardiac signals back to the sensing circuitry of the stimulation device. Typically, a single-chamber stimulation device requires one lead, whereas a dual-chamber stimulation device requires two leads (one for the atrium and another for the ventricle). The conductor coil is the internal core of the pacing lead through which current flows between the pulse generator and the electrodes.
A lead may be unipolar or bipolar. A unipolar lead is a pacing lead having one electrical pole external to the pulse generator, which is usually located in the heart. The unipolar lead has one conductor coil. The electrical pole is typically a stimulating cathode (i.e., negative pole) at the distal tip of the lead. As used herein, a distal end of the lead is the end which is farther away from the stimulation device. A proximal end of the lead is the end which is connects to the stimulation device. The cathode is the electrode through which a stimulating pulse is delivered. The anode electrode (i.e., the positive pole) is the case, or housing, of the stimulation device. A stimulating pulse returns to the anode using the body tissue as a return current path. A unipolar lead is relatively small in size and is theoretically more reliable than a bipolar lead. However, a unipolar lead/pacing system is more susceptible to interference by other electrical activity in a patient""s body, such as inhibition due to myopotentials, and further may be prone to pectoral stimulation.
On the other hand, a bipolar lead is a pacing lead with two electrical poles that are external to the pulse generator. The bipolar lead has two conductor coils. The stimulating cathode is typically at the distal tip of the pacing lead, while the anode is an annular (i.e., ring) electrode which is few millimeters proximal to the cathode. As such, bipolar leads are less prone to pectoral stimulation. A bipolar lead has better signal-to-noise ratio than that of a unipolar lead, and thus, is less susceptible to interference from myopotential inhibition.
In practice, the cathode (i.e., stimulating) electrode is typically placed in contact with the heart tissue in order to stimulate the cardiac tissue. The anode electrode, however, does not need to be in contact with the heart tissue, since blood tends to conduct electrical currents better than the tissue itself. Nonetheless, it is preferable to have the sensing electrode in contact with the heart tissue to allow the detection of more distinct signals. For more details on bipolar lead structure and electrode placement, reference is made to commonly-assigned U.S. Pat. No. 5,522,855, issued to Hoegnelid on Jun. 4, 1996, and is incorporated herein in its entirety by reference. Moreover, for details on quadrapolar (four electrodes) lead structure and electrode placement, reference is made to commonly-assigned U.S. Pat. No. 5,304,219, issued to Chemoff et al. on Apr. 19, 1994, and is incorporated herein in its entirety by reference.
While bipolar leads are reknown for their improved sensing characteristics, some physicians still prefer unipolar leads since the additional stiffness of the bipolar leads makes them handle differently. Programmable polarity has the known advantage of permitting physicians the ability to implant the leads of choice and stock only one stimulation device model that can handle both leads. Further, if bipolar leads are initially implanted, the polarity can be modified based on the patient""s needs.
There has been a long felt need to simplify the implantation of dual-chamber stimulation devices by using only one lead, commonly referred to as a xe2x80x9csingle-passxe2x80x9d lead. The earliest known single-pass leads was a xe2x80x9cmulti-polarxe2x80x9d device (1974) by Berkovits (U.S. Pat. No. 3,825,015) in which two electrodes were placed in the ventricle and four electrodes were placed in the atrium, however, only the best two of the four atrial electrodes were used ultimately.
xe2x80x9cQuadrapolarxe2x80x9d leads (1975) were attempted by Woollons et al. (U.S. Pat. No. 3,903,897) in which two electrodes were located in the apex of the ventricle and two xe2x80x9cfloatingxe2x80x9d electrodes in the atrium. However, these leads were very stiff, and positioning the atrial electrodes to make contact were difficult.
Both of these systems were extremely stiff, and either had poor contact with atrium or had extremely large, complicated connectors.
One of the simplest single-pass leads was a two-electrode lead (1979) by O""Neill (U.S. Pat. No. 4,154,247) in which an electrode was placed in each of the atrium and the ventricle.
Of course, pacing thresholds were also improved upon by forcing the atrial electrode(s) to make direct contact with the cardiac tissue. This may be achieved by either pre-forming the lead in the region of the atrial electrode (as in the ""247 patent, supra) or by using various anchoring or active fixation techniques by Grassi (U.S. Pat. No. 4, 624,265) and Hess (U.S. Pat. No. 4,664,120).
Later, xe2x80x9ctripolarxe2x80x9d electrodes were developed with two electrodes in the apex of the ventricle and a single electrode in the atrium (see U.S. Pat. No. 4,585,004 to Brownlee). Other attempts at tripolar electrodes included a single electrode in the ventricle, with two electrodes in the atrium (see U.S. Pat. Nos. 4,711,027 (Harris); 4,962,767 (Brownlee); and also 5,172,694 (Flammang)).
These tripolar leads of the prior art are chosen since they permit synchonicity between the atrial and ventricular chambers of the heart while providing a less stiff lead, with a smaller proximal connector (which affords a small, less complicated connector on the stimulating device) and without resorting to implanting an additional lead.
For purposes of delivering high voltage shocks, a xe2x80x9cdefib leadxe2x80x9d typically has at least one, and preferably two, transvenously placed shocking coils. While sensing may occur between a ventricular tip electrode and a ventricular ring electrode, it is also known to sense in an xe2x80x9cintegrated bipolarxe2x80x9d fashion between the ventricular tip and a ventricular coil electrode (or between the atrial electrode and an SVC coil electrode).
However, these prior art leads do not offer full programmability of the electrode polarity with a simplified lead structure for ease of manufacture and improved reliability. Accordingly, there is a need in the cardiac pacing technology to offer a lead system which offer programmability, is compactly structured, can be easily placed in a patient""s heart and, therefore, is inherently more reliable.
To overcome the above-mentioned problems, the invention provides an improved single-pass lead comprising three electrodes suitable for sensing intrinsic cardiac activity in two chambers of the heart, for stimulating cardiac tissue in at least the ventricle, and having programmable unipolar or bipolar polarity.
In a first embodiment, suitable for use in an implantable pacemaker having a xe2x80x9cVDDxe2x80x9d mode, one tip electrode is located at the distal end in the ventricle, one ring electrode is xe2x80x9cfloatingxe2x80x9d in the atrium, and a second ring electrode is positioned near or just below the tricuspid valve.
In a second embodiment, suitable for use with an implantable cardioverter-defibrillator device, one tip electrode is located at the distal end in the ventricle, one ring electrode is xe2x80x9cfloatingxe2x80x9d in the atrium, and the second electrode is a coil electrode positioned in the ventricle proximal to the tip electrode and extends near or just below the tricuspid valve.
Hereinafter, the second electrode will be referred to as the xe2x80x9ctricuspid electrodexe2x80x9d, regardless of the type or exact construction, and will be construed to cover any electrode in proximity to the tricuspid valve.
Ventricular pacing and sensing can occur in a unipolar fashion from the distal tip electrode to the stimulation device housing (also known as the case electrode), or in a bipolar fashion from the tricuspid electrode to the ventricular tip electrode.
Atrial sensing can be achieved in a unipolar fashion from the atrial ring electrode to the housing, or in a bipolar fashion from the atrial ring electrode to the tricuspid electrode.
While the preferred embodiment is directed toward a lead suitable for VDD pacing and sensing, the present invention could be adapted to include DDD pacing and sensing if the atrial ring electrode/lead body was dimensioned so as to make contact with cardiac tissue, such as near the SA node or the atrial appendage, by preforming the lead in the region of the atrial ring electrode.
Advantageously, sensing of atrial and ventricular cardiac signals is enhanced, since the dipole created between the tricuspid electrode and either the ventricular tip electrode or the atrial ring electrode is larger (i.e., the electrodes are separated by a larger distance than standard bipolar lead arrangements). The present invention thereby detects a larger differential signal than conventional bipolar leads, is immune to myopotential signals, and still is less likely to cause pectoral stimulation.
Furthermore, the single-pass lead of the present invention adds only one additional conductor and electrode to a conventional bipolar lead, and thus is easier to implant, more reliable, and also easier to manufacture.

Implantable stimulation system for providing dual bipolar sensing using an electrode positioned in proximity to the tricuspid valve and programmable polarity