Right side universal electrocardiogram sensor positioning mask and method

[0001] This is a continuation-in-part of U.S. patent application Ser. No. 10/021,937, filed on Dec. 13, 2001, now U.S. Pat. No. 6,553,246, issued Apr. 22, 2003, for a Universal Electrocardiogram Sensor Positioning Device and Method which is a continuation-in-part of U.S. patent application Ser. No. 09/461,701, filed on Dec. 14, 1999, now U.S. Pat. No. 6,400,977 BI, issued Jun. 4, 2002, for A Universal Electrocardiogram Sensor Positioning Device and Method, which is a continuation of U.S. patent application Ser. No. 09/022,730, filed on Feb. 12, 1998, now U.S. Pat. No. 6,006,125, issued Dec. 21, 1999.

[0002] 1. Field of the Invention

[0003] The present invention relates to a disposable dermal chest mask for assistance in establishing electrical communication between sensors on a human chest and electrocardiograph machines. More particularly, it relates to a universal electrocardiogram sensor positioning mask and method for the right side of human chests for all adult sizes including size extra large.

[0004] 2. Description of the Prior Art

[0005] Diagnostic medical equipment increasingly relies upon electrical contact with specific areas of the human body for evaluating the health status of patients. One of the most utilized and relied upon diagnostic tools is the electrocardiogram, sometimes referred to as an ECG. Leads or signal wires from the analytical apparatus are attached to a metallic or otherwise conductive body sensor electrode which is attached to the patient's skin at the desired points of contact. Electrical current generated by the heart in a person's chest flows to the surface and at the skin produces differences in electrical voltage which can be measured between pairs of electrodes placed at two points on the skin. A twelve-lead electrocardiograph is the most utilized for recognizing ischemic electrocardiographic changes.

[0006] To administer a resting twelve-lead ECG, it is necessary to apply ten electrodes to various points on the torso and limbs of a patient to measure and analyze cardiac data. Twelve recordings for the ECG are made from nine active lead positions with the tenth being used as a ground. An electrode portion of a lead may in fact consist of an alternative form of sensor, and the terms “electrode” or “sensor” for purposes of this disclosure are interchangeable. A lead wire connecting a sensor to the diagnostic equipment could possibly in fact consist of a radio or an optical signal. Six of the ten electrodes are applied to the patient's chest over prescribed anatomical landmarks. The remaining four electrodes are applied to each of the patient's limbs. The chest electrodes are known as the precordial leads and the limb electrodes are called limb leads. The precordial leads are designated V₁, V₂, V₃, V₄, V₅, and V₆. The limb leads are designated LA, RA, LL, and RL (ground).

[0007] It is generally acknowledged that it is critically important to place the precordial leads with precision in order to obtain accurate and repeatable recordings. However, accurate placement and attachment of a large number of leads can be difficult and time consuming and requires knowledge, skill, and diligence on the part of the person attaching the electrodes or sensors. Mechanical problems in attaching multiple leads to a patient range from tangling of lead wires, and excessive time consumed in pairing lead wires with the appropriate electrodes, to difficulty in locating anatomical landmarks on a patient with precision.

[0008] Problems occur if the leads are not properly placed and are located higher or lower than optimal. The position of the precordial leads is determined by the anatomical features of the patient's chest and not by the position of the heart itself. Research reported in the electrocardiography literature indicates that precordial leads placed one inch or more from their true anatomical landmarks can result in misinterpretation of the patient's ECG. This may result in or contribute to diagnosis errors, false hospital admissions, sending sick people home, or have other negative impacts on diagnosis or treatment. The placement problem is compounded when serial comparisons are made between two or more ECGs taken over time. For example, if V₄ was placed one inch too high for one test and one inch too low for another, the difference of two inches may produce what appears to be a significant difference between the two ECGs when in fact there was no physiological change in the patient's heart condition.

[0009] To place the precordial leads accurately requires training in using both visual and palpatory cues to find the anatomical landmarks on each patient. Placement accuracy is also affected by the time and diligence dedicated to placing the precordial electrodes. An experienced and conscientious electrocardiologist may require and devote ten minutes to palpation and ascertaining the exact precordial landmarks. However, in busy clinical environments or emergency situations, medical personnel are often so rushed they may not even palpate the patient. Under those conditions, precordial leads are commonly placed with inadequate palpation and with little attention to a patient's particular anatomy. As a consequence, individual leads are often misplaced by two and as much as three inches from their true anatomical landmarks. In addition, training and maintaining the necessary skill for proper placement of individual leads is time and resource consuming and often not adequate. With six precordial leads, there are six chances to misplace electrodes. Research shows that V₁ and V₂ electrodes are typically placed high and wide of their targets—the fourth intercostal space on each side of the sternum. Likewise, precordial electrodes V₄, V₅, and V₆ are most often misplaced low and wide. Electrode V₃ is most often misplaced too low. The most obvious conclusion to be drawn is that lead placement is often not accurate.

[0010] After the individual electrodes are positioned on a patient, it is necessary to attach the ten lead wires. Each lead wire is labeled to correspond to one of the anatomical landmarks, i.e., V₁, V₂ . . . V₆ . . . RL. Should lead wires be crossed, interpretative ECG monitors can detect and alert the operator of a possible crossed lead wire situation, but that requires additional time to check connections and to take corrective action. This is a time consuming operation which increases the risk in an emergency situation. Crossed lead wires are a more significant problem when the ECG monitor does not provide interpretation of the recordings and cannot alert the operator of this possibility. In such a case, the ECG signals for each of the twelve leads are recorded on hard copy to be read at a later time. The physician or technician reading the ECG recordings may recognize the error but by that time the patient has usually been disconnected from the monitor. The present invention reduces or eliminates the chances of either of these situations from occurring.

[0011] Periodic electrocardiograms are important for providing a cardiographic profile of a patient for early detection and diagnosis of cardiovascular diseases. In order to provide an accurate profile, it is important not only that the electrocardiogram be taken with sensors affixed accurately, but that the sensors be placed at the same location on the patient in the subsequent exam as for the previous examination. The efficacy and the repeatability of the tests is critical so that a series of ECG results can be compared to provide a continuing profile of a patient's medical history for diagnosis and treatment of heart disease.

[0012] In urgent situations, including those electrocardiograms taken with the current standard electrode lead wire system, during an acute symptomatic episode there may only be time to attach two to four individual electrodes to the patient. Therefore, it is desirable to have a mask which enables more electrodes or sensors to be quickly and accurately secured during such an acute symptomatic episode. Alternatively, it may be necessary to quickly remove some or all of the chest leads when a patient is experiencing a heart attack or in other emergencies in order to administer CPR, to massage the heart, administer drugs, to apply electrical defibrillation paddles, or for other purposes. Accordingly, critical time can be lost both in the removal of the chest leads of the ECG test equipment in order to administer aid to a patient and in their subsequent replacement after aid has been administered.

[0013] Because of the inadequacies of prior art devices to solve these problems, there has been a need for a system which: prevents or curtails the possibility of ECG electrode leads or wires from being entangled or crossed; provides quick removal of some of the sensors when it is necessary to administer aid to a patient having a heart attack; provides accurate and appropriate repeatable placement of electrodes at substantially the same location on the patient; accurately and repeatedly obtains signals from electrodes by efficient and effective electrical transmission; and may be attached by persons with varying levels of experience including those with little training.

[0014] The inventions disclosed in the five related patents to Kelly—U.S. Pat. No. 5,865,740, No. 5,865,741, No. 5,916,159, No. 6,066,093, and No. 6,157,851—involve various alternatives for the purpose of trying to effect those goals. The common invention in those patents is a disposable electrode positioning mask that utilizes a non-conducting flexible sheet in the form of a mask having a predetermined dimensional sensor array. The flexible sheet serves as a template for aligning connectors or sensors, either of the electrode or electrodeless type, on the chest of a patient for transmitting electrical impulses.

[0015] An important aspect of the Kelly inventions is that the flexible non-conductive sheet is provided in a plurality of sizes, with each size having arrays V₁, V₂, V₃ and V₄, at substantially the same locations and having arrays V₅ and V₆ at different locations depending on size. In this regard, the locations of V₅, and V₆ are based on a measured distance between the left midclavicular line and the left midaxillary line on the chest of a patient.

[0016] An alternative of the related inventions is that the dimensional array on the flexible non-conductive sheet is provided with cutouts to form a template or mask which is placed on the patient's chest and then conventional electrodes can be positioned in the cutouts. Still another aspect of the related inventions is that the template can be provided with a plurality of conventional tab, snap, or other electrodes affixed on their top sides to the flexible sheet to be placed against the patient's chest. The electrodes are positioned in accordance with the predetermined dimensional array. Small cutouts, or openings, in the template expose the electrode tabs for attaching lead wire clips. Snap electrodes protrude through the template to permit the attachment of lead wire snap connectors.

[0017] In a further aspect of the related inventions, the top sides of individual electrodes can be lightly affixed to the flexible sheet of material at the predetermined dimensional array locations. The sheet can be placed on the patient's chest and then peeled away leaving the electrodes properly located on the chest. Each of these concepts can be employed in the concept of the basic embodiment of the present invention as disclosed in the related patent application and U.S. Pat. Nos. 6,006,125 and 6,400,977 BI, designated earlier.

[0018] Yet another aspect of the Kelly inventions is a method of sizing a patient for fitting a sensor positioning mask having a flexible sheet with a fixed dimensional V₁-V₆ array positioned in a specific size configuration appropriate for standard electrocardiographic recording. The distance between V₁ and V₂ is a predetermined distance plus or minus a small amount, and the distance between V₂ and V₄ is a predetermined distance plus or minus a small amount, with V₃ located substantially midway between V₂ and V₄, and V₅ being equidistant between V₄ and V₆. The method of sizing the disclosed related inventions comprises the steps of measuring the distance between the midclavicular line and a midaxillary line on the chest of the patient, and selecting a positioning mask size of those inventions based on the measured distance. This procedure is eliminated by the related application, the above-identified '125 and '977 patents, and the present invention.

[0019] The prior art U.S. Pat. No. 4,583,549 to Manoli and the U.S. Patents to Kelly describe precordial electrodes fixed in a preset pattern on a flexible sheet in positions corresponding to the anatomical landmarks on the patient. The basic problem with all of these inventions is that they require multiple sizes of sensor positioning masks to fit various sized persons.

[0020] Manoli envisions, without stating any dimensions, three sizes—a pediatric, medium adult, and large adult—to fit most children and adults within the population. Kelly describes three sizes—small, medium, and large adult—to fit most adults within the population. Manoli does not describe how one determines which size mask a patient would require. Presumably, under Manoli, a small person requires the smallest of the three sizes, i.e., the pediatric, and a large person requires the largest. The invention disclosure is indefinite in this regard.

[0021] Thus, Manoli does not describe how to size a patient, and it is common for persons placing individual electrodes to make errors. If similar errors are made when sizing the patient for Manoli's device, it is quite likely that the wrong size device would be selected. Once a device is applied to the patient, it would be possible to check the correctness of fit. If wrong, however, i.e., the V₆ electrode was located some distance from the patient's midaxillary line, the device would have to be removed and replaced by a more appropriate size device. This trial and error approach wastes time and materials since the first device would need to be discarded without ever being used to take an ECG.

[0022] The more recent U.S. Pat. No. 5,678,545 to Stratbucker describes an adhesive sheet having a fixed array of individual electrode groups disposed at varying locations to provide a “one size fits all” system. One embodiment has twelve precordial electrodes with one electrode each at V₁, V₂, and V₃ and groups of three electrodes each at V₄, V₅, and V₆, while other embodiments are suggested for groups of electrodes for other electrode locations in order to achieve a “one size fits all” system.

[0023] Stratbucker describes multiple groupings of electrodes for a “single size” system but it is necessary to determine which electrode in each group is within the region of the appropriate location on a patient's chest: for each group of electrodes, there must be a determination of which electrode is closest to the anatomical landmark. Such a determination is time consuming and would at least be impeded by the fact that palpation will be difficult to perform once the sheet is placed over a patient's chest. Moreover, each group of electrodes provides a source for error since there are three electrodes to choose from in each group. Assuming one electrode in each group is most correct, the probability of randomly selecting the best electrode from each of the groups is 0.33^X, where X equals the number of groups. If there are three groups of electrodes, as described in one embodiment where V₄, V₅, and V₆ consist of groups of three electrodes each, the probability of randomly selecting the appropriate electrode from each group is 0.037, or 1 out of 27 possibilities. Stratbucker relies on a judgment determination for each group of electrodes and therefore selection is time consuming and inexact due to the device physically covering the patient's anatomical features.

[0024] Although Stratbucker tries to curtail the possibility of placing conventional individual electrodes far from the region of proper placement by confining the decision to simply selecting one electrode out of each group of three electrodes, medical personnel must still ascertain which electrode is appropriate for each group of electrodes. Not only does this allow for error, it also reduces the chances of consistent electrode placement from one test to the next, thereby confounding any serial comparisons between tests. It also increases the length of time to administer a resting ECG since a separate decision must be made for each group of electrodes.

[0025] The inventions of related U.S. Pat. Nos. 6,553,246, 6,006,125 and 6,400,977 BI, uniquely solved those problems by providing a multiple precordial array of sensor electrodes in a single device that will fit essentially three or four classes of sizes of adults and in which sizing is accomplished simply by the determination of the location of a single sensor which is closest to a selected anatomical landmark. This is achieved by a device having more precordial sensors than the six chest electrodes needed for the resting ECG but significantly less than the number of those taught by Stratbucker.

[0026] In the above-identified inventions, some sensors may serve multiple roles to accommodate different patient sizes within one array by utilizing a particular set of sensors. Each set of sensors corresponds to a specific patient size that can be characterized as small, medium, large, or extra large. Once the device of the invention is applied to the patient, one simply and quickly ascertains which of four V₆ sensors lies on or closest to the patient's midaxillary line and then connects the electrode sensor lead wires to the corresponding set of sensors in which the V₆ is designated as one of the four selections: small, medium, large, or extra large. The inventions of these patents greatly simplify the heretofore universal unresolved problem of instantaneous patient sizing during use, while providing the additional benefits of reducing the cost of production and eliminating the need to stock different size devices.

[0027] The present invention differs from the related inventions designated in the related applications portion of this specification to provide a different apparatus and method to achieve different results while utilizing the basic architecture of those inventions. The purpose of the related inventions is to provide a universal electrocardiogram sensor and positioning device which will fit an accurately estimated ninety-nine percent (99%) of human torso sizes of the adult population as well as a substantial portion of the teenage population. The present invention provides a unique modification to these inventions whereby the same sensor and positioning device can be utilized for right side chest placement of sensors as well as standard left side placement for performing either right chest or left chest ECGs.

[0028] It has been determined that it is desirable in certain cases to obtain a right chest ECG, in addition to a left chest ECG, such as, and especially when discrepancies from normal are discovered in a left chest ECG. In such cases, a right chest ECG is often considered desirable but sometimes in the past has been avoided because of the time required to repeat the basic test and the unfamiliarity of technicians for palpating and properly placing sensors for performing a right chest ECG. The purpose of the present invention is to simplify and greatly speed up both procedures by making a universal sensor mask which, in addition to fitting 99 percent of the chest sizes of adults, and most older children, for left chest ECGs, can also be utilized for right chest ECGs for the same persons.

[0029] The present invention is a universal ECG multiple sensor dermal precordial mask for fitting different sizes of human bodies for obtaining electrocardiographic information of either the left or right side of a human chest using sensors V₁, V₂, V₃, V₄, V₅, and V₆ for left side recording disposed on one side of the mask and VR₁, VR₂, VR₃, VR₄, V₅, and VR₆ for right side recording disposed on the opposite side of the mask. The mask comprises a sheet of non-conductive material incorporating at least nine sensor positions for the placement of sensor electrodes forming three sets of sensor groups including three alternate positions for each V₅ and V₆ (V₅ and VR₆) positions. The nine sensor positions are disposed in a specific geometric arrangement with the V₁-V₄ (VR₁-VR₄) positions being utilized for all sizes of bodies. The V₅ (VR₅) position has two independent sensor positions and shares a third with the V₆ (VR₆) positions, and the V₆ (VR₆) position has two additional positions.

[0030] The present invention also includes a method for sensor placement for electrocardio-graphic recording for either the left or the right side of a human chest by means of a universal ECG multiple sensor dermal precordial mask for fitting four different sizes of human bodies including extra large. The mask incorporates sensors V₁, V₂, V₃, V₄, V₅, and V₆ for left side recording, and VR₁, VR₂, VR₃, VR₄, VR₅, and VR₆ for right side recording. The method comprises the steps of providing a mask having at least ten precordial sensor positions designated on the mask on opposite sides thereof with the V positions disposed on one side and the VR positions disposed on the other side and forming mirror images of each other, said V and VR positions each forming at least four sets of sensor groups including four alternate sensor positions for each of the V₅ and V₆ (VR₅, and VR₆) sensors. The ten sensor positions are disposed in a specific geometric arrangement with the V₁-V₄ (VR₁-VR₄) sensor positions being utilized for all sizes of bodies. The V₅ (VR₅) position has two independent sensor positions and shares two positions with the V₆ (VR₆) positions, and the V₆ (V₆) position has two additional positions. The mask includes indicia for determining which sensor positions correspond to the four sensor sets. The side of the mask is selected which corresponds to the side of the chest that the ECG is intended to record. The mask is aligned on a patient's chest so that the V₁ and V₂ sensors are disposed approximately on opposite sides of the patient's sternum. It is then ascertained from the indicia which one of the four V₆ sensor positions lies on or is closest to the patient's midaxillary line, and then electrocardiographic information is obtained from the corresponding set of sensors which include the V₆ sensor.

[0031] It is therefore an important object of the present invention to provide a universal ECG multiple sensor positioning device which provides all of the sensors for performing an ECG on both the left chest and the right chest of a human body in a single device.

[0032] It is another object of the present invention to provide a universal ECG multiple sensor positioning device whereby one size fits all including extra large rather than requiring a multitude of different sizes thereby achieving economic benefits of high volume production and simplified sales and distribution.

[0033] It is a further object of the present invention to provide a disposable and universal ECG sensor positioning device and method of use in which less time is needed to perform an ECG since the steps used to determine which mask size to utilize and the logistics of maintaining different size devices in inventory are eliminated and which can be thrown away after use providing less risk of transmitting infection.

[0034] It is still another object of the present invention to provide a universal ECG sensor mask and method of use in which simplified, efficacious, and repeatable sensor placement results on either the left or right side of a human chest are guaranteed.

[0035] It is yet a further object of the present invention to provide a single multiple sensor mask and method of use in which a twelve-lead electrocardiogram which provides the most common means of recording electrical activity of the heart to capture changes for either left chest or right chest ECGs.

[0036] It is still another object of the present invention to provide a universal ECG electrode mask and method of use in which eight different ECGs can be performed by the same device.

[0037] And it is still a further object of the present invention to provide a universal electrocardiogram sensor mask for either left chest or right chest ECGs which covers ninety-nine percent (99%) of the adult human torso population including extra large sizes and a large portion of the teenage population.

[0038] Other objects and advantages of the present invention will become apparent when the method and apparatus of the present invention are considered in conjunction with the accompanying drawings.

[0044] Reference is made to the drawings for a description of the preferred embodiment of the present invention wherein like reference numbers represent like elements on corresponding views.

[0045] FIG. 1 illustrates a plan view of the universal disposable ECG sensor positioning mask of the present invention for three sizes of human torso for placement on the left chest of a patient for performing an ECG test. FIG. 2 illustrates a plan view of the opposite side of the universal disposable ECG sensor positioning mask of FIG. 1 for placement on the right chest of a patient for performing a right chest ECG test. FIG. 3 illustrates a plan view of the universal disposable ECG sensor positioning mask of the present invention for four sizes of human torso including extra large for placement on the left chest of a patient for performing an ECG test. FIG. 4 illustrates a plan view of the opposite side of the universal disposable ECG sensor positioning mask of FIG. 3 for placement on the right chest of a patient for performing a right chest ECG test. FIGS. 1-4 illustrate masks which can be printed on the opposite or reverse sides of the mask base layer while FIG. 5 illustrates the masks being printed on the same side of the base layer at opposite ends thereof in a pair of wings configuration.

[0046] The word “universal” as used in describing the mask is an abbreviation of the descriptive colloquial terminology—one size fits all. The masks of the related inventions fit up to ninety-nine percent (99%) or more of the adult population, including overweight and extra large torso persons, and most older children as well. The term “disposable” means that the mask is intended for a single or one time use only. However, the physical form of the mask could be reusable for more than one test, and a more permanent embodiment of the design could be a truly reusable mask possibly requiring sterilization, cleaning, and/or fresh adhesive for reuse. Therefore, the term “disposable,” as used in the descriptive preamble of the claims, is provided solely as an aid for most accurately describing the preferred embodiment of the invention in relation to the prior art and should not be interpreted as a limitation on the forms of the invention and scope of the claims.

[0047] The mask is a dermal chest mask 11 which is formed of a sheet of flexible non-conducting material 13 for carrying or positioning ten chest electrodes or electrodeless sensors 15, or simply holes therein for the positioning thereof, for connection by electrical lead wires (not shown) to a standard electrocardiographic diagnostic machine. The alternate means for sensor placement is designated in the claims hereof by the term “sensor positions” which includes all of the aforementioned and any other means for sensor placement.

[0048] The flexible non-conductive web or sheet may be formed from any preferably transparent natural or synthetic material which is capable of accepting a print for the electrical contact areas and the associated indicia. Generally any cellulosic material, polyester, polyolefin, polyvinyl chloride, nylon or mixtures thereof would be suitable. Cotton, polypropylene, or polyethylene can be used if cost is a consideration. However, polyester is likely the most preferable.

[0049] While the most practical form of the invention incorporates the ECG sensors 15 into the flexible sheet 13, a less sophisticated form of the invention can utilize simply the specific arrangement of sensor positioning taught herein by the placement of holes for the electrodes in the specific geometric pattern called for herein on the sheet. The standard ECG electrodes can then be placed in the holes and adhered to the patient's skin through the holes. Other masks using the specific sensor positioning arrangement and indicia of the present invention are also contemplated as within the scope of the invention.

[0050] In the prior art, the sensors are printed or secured onto one side of the non-conductive web or sheet for the purpose of administrating typical left chest ECGs. In order to administer a right chest ECG using the same mask, the sensors are also printed or secured onto the opposite sides of the web or sheet as will be described more in detail hereinafter.

[0051] Detachable limb lead sensors 17 can also easily be provided integral to the mask during the manufacturing process. In a preferred embodiment, they are formed integral to the mask with a means for easy detachment such as a set of perforations along the line of joinder 19 of the limb lead sensor to the mask 11. The ends of the limb lead sensors are provided with an electrical contact area 21 whereby an electrical lead can be connected to the sensor by any appropriate means such as an electrical connector clip.

[0052] The receptor sensor electrode positions 15, which are located on the mask 11, are spaced relative to each other in a specific geometric configuration appropriate for electrocardial recordings from most sizes (FIGS. 1 and 2) to essentially all sizes of adult human torso (FIGS. 3 and 4). Each receptor sensor or electrode position is adapted for electrical connection with the skin of a patient's body for detecting and transmitting electrical signals generated by the patient. The preferred embodiment of the mask includes conductor strips 23 each of which extends to and electrically connects to a sensor. The other end of each conductor strip terminates in a connector end or terminal which engages any type of connection or cable junction for electrical connection with the electrocardiograph analyzer. Separate leads could be utilized for a locator mask which simply provides sensor positions.

[0053] Three (FIGS. 1 and 2) or four (FIGS. 3 and 4) discrete electrical contact or terminal area groups are provided for each left- and right-sided ECGs for connection to an ECG machine to accommodate up to four different classes of adult human torso sizes: small, medium, large, and extra large. The four individual terminals 25 for V₁ to V₄ are contiguous, and six discrete terminals 27 are provided for V₅ and V₆ in four sizing configurations. A mask designed for fitting only three classes of human torso sizes are described in the related '125 and '977 patents. Obviously, a supplier of a mask utilizing the architecture of the present invention may choose to provide a mask utilizing less than all four size choices.

[0054] The terminal ends 25, 27 of the conductor strips are preferably disposed adjacent to each other in three (FIGS. 1 and 2) or four (FIGS. 3 and 4) identical paired patterns to facilitate connection to a common connector which can be utilized for either three or four classes of sizes. A customized clip is envisioned to simplify use of the mask of the present invention by permitting a single-clip connection. Pin locator cut-outs 29 and indicia 31 for the clip allow it to be selectively engaged to the mask for connecting a certain or selected set of six sensors to the ECG machine.

[0055] In a preferred embodiment of the invention, where the sensors and leads are formed integral to the mask, means are required to enable the sensors. In order to establish electrical connection between a human body and the receptor sensor positions 15, a biocompatible electrically conductive adhesive, such as hydrogel, is applied to the body contacting sides of the sheet at each sensor site for adhesion to the skin of the patient. The adhesive is generally transparent and shown in outline 16 in the drawings. Hydrogel is commercially available as are other suitable conductive adhesives and any suitable electrodermal adhesive would serve the purpose. The size of the adhesive area is generally between 3 and 9 square centimeters. When the mask is pressed against the skin of the patient's chest, the sensors are electrically connected to the patient at each receptor.

[0056] The gel-coated adhesive area of the mask 11 includes at least one release liner in releasable adhesive contact with the gel covering the sensors 15. Because the release liner can be transparent, and is simply a sheet of material, it is not shown in the drawings. Separate release liners could be provided for each sensor, but in the preferred embodiment, a single release liner covers all of the sensors associated with a left-side ECG and a second release liner covers all the sensors associated with a right-side ECG. The mask can be removed from the liner in a single operation to expose all of the sensors as a unit (except for the limb lead sensors). The limb lead sensors 17 are released individually having been separated at the perforations 19 along the line of joinder with the mask. The flexible release liner covering the receptors may be made from a suitable dielectric film or coated paper which includes polypropylenes, polyesters, olefinic polymers, polyvinyl chloride and its copolymers, acrylic rubbers, ABS resin, and the like. Commercial suppliers for these materials are listed in the related patents.

[0057] The receptor electrodes 15 and the conductor strips 23 can be produced from any electrically conductive material, e.g., metal, foils, conductive polymers, graphite, carbon fibers, and the like. They include gold, copper, silver, tin, aluminum, N-vinyl pyrrolidone, and alloys or mixtures thereof. The receptor/conductors can also be made from a conductive paste of a metal in particle form in a suitable binder which is printed or silk screened onto the flexible non-conductive sheet or electrolessly deposited. A connective polymer may be heat pressed or otherwise conventionally secured to the web or sheet.

[0058] Copper strips could be utilized and electrolessly deposited on the polymeric sheets in a range of thickness from about 0.25 to about 5 microns, more preferably from 0.25 to 1.5 microns, and most preferably 0.4 microns in thickness. A metallic ink may be preferable such as a commercially available silver ink. Each of the conductor strips are less than 10, and preferably less than 5, micrometers in thickness, whereby the flexibility of the connector and adhesion of the gel surface to the skin are substantially enhanced.

[0059] The exposed conductive strips 23 may be partially covered with a dielectric layer for insulating the conductive pathways. This coating can be transparent and is also shown in the drawings in outline 24. The strips are coated with a dielectric polymeric material in such a way so that only selective portions comprising the sensor 15 and the electrical contact or terminal areas 25, 27 are exposed. Suitable dielectric coatings include polyesters, ethylene-vinyl acetate copolymers, polyvinyl chloride and its copolymers, terpolymers such as acrylonitrile-butadiene styrene (ABS resins) and inter alia.

[0060] Therefore, a preferred laminate for the flexible sheet of the invention can comprise several layers, several of which can be transparent. A preferred embodiment of the invention would include: (1) a base layer of a flexible non-conductive film of polyethylene terphthalate; (2) a bond layer for the conductor strips such as a catalyst in contact with a conductive ink; (3) a conductor strip comprised of silver ink; (4) an adhesive layer such as hydrogel superimposed upon the silver ink in the sensor areas of the mask, or alternatively, a dielectric layer superimposed upon the silver ink in the conductor strip area of the mask; and (5) a flexible release liner as the top layer superimposed upon at least the adhesive layer of the mask.

[0061] In order to utilize the mask of the present invention to take right chest ECGs, a mirror image of the mask for left chest ECGs must be provided on opposite sides thereof. This is effected in either of two ways: first, by turning the mask over and printing the identical bond layer, conductor strips, and adhesive layers on the opposing side of the mask in an identical overlay which creates the mirror image of the opposite or left chest side. It is then covered with a flexible release liner as the top layer. As a result, two separate masks are provided on opposite sides of the base layer covered by separate release liners but only one is utilized depending upon which side of the mask from which the release liner is selectively removed. The second way is by printing both masks on the same side of the base layer extending in opposite directions from the center of the mask in a spread wings configuration whereby the left and right chest masks are disposed at opposite ends of the same side of the mask. In the design shown in FIG. 5, separate electrical connectors are required for the left and right chest masks unless the electrical conductor printing is rerouted to provide terminal area groups which can be engaged by a universal design electrical connector which will accommodate both right and left chest ECG recordings. An alternative design for FIG. 5 could over lay V1/VR2 and VR1/V2 with the electrical printing using a common connector.

[0062] Since the mask of the present invention is designed for use by untrained personnel as well as a trained individual, the sheet material of the mask contains designator markings or indicia to simplify attaching to or positioning of the mask on the patient's chest. It is sufficiently self-describing such that it allows a person untrained in electrocardiography to position the mask to obtain highly reliable and repeatable ECG signals for either left or right chest ECGs. It also includes indicia for sizing the patient.

[0063] FIG. 1 shows the nine-sensor array for left chest ECGs which includes singular V₁, V₂, V₃, and V₄ sensor positions and three alternate V₅ and V₆ sensor positions. The V₅ and V₆ positions each have two independent sensor positions (V_5S, V_5M, V_6M, and V_6L) and share a third position (V_5L/V_6S). FIG. 1 also shows the indicia therefor. Indicia V1, V2, V3, and V4 indicate a single position for each of the V₁, V₂, V₃, and V₄ sensors. Indicia V5S indicates V₅ small; V5M indicates V₅ medium, V5L/V6S indicates either V₅ large or V₆ small. V6L correlates to V₆ large. The S, M, and L indicia are provided to aid in selecting which set of sensors are to be utilized. The additional indicia between V1 and V2, and V6M and V6L, aid the user in positioning the mask. The indicia 31 proximate the pin locator cut-outs 29 aid in selecting the electrical connection for sensor set selection.

[0064] FIG. 2 shows the nine-sensor array for right chest ECGs which are the mirror image of the left chest array. The indicia are the same and differentiated from the left chest indicia by an additional R designation. The array includes, like the left chest array, singular VR₁, VR₂, VR₃, and VR₄ sensor positions and three alternate V₅ and VR₆ sensor positions. The V₅ and VR₆ positions each have two independent sensor positions (VR_5S, VR_5M, VR_6M, and VR_6L) and share a third position (VR_5L/VR_6S). FIG. 2 also shows the indicia therefor. Indicia VR1, VR2, VR3, and VR4 indicate a single position for each of the VR₁, VR₂, VR₃, and VR₄ sensors. Indicia VR5S indicates VR₅ small; VR5M indicates V₅ medium, VR5L/VR6S indicates either VR₅ large or VR₆ small. VR6L correlates to VR₆ large.

[0065] FIG. 3 shows the ten-sensor array for left chest ECGs which includes singular V₁, V₂, V₃, and V₄ sensor positions and four alternate V₅ and V₆ sensor positions. The V₅ and V₆ positions each have two independent sensor positions (V_5S, V_5M, V_6L, and V_6XL) and share two positions (V_5L/V_6S and V_5XL/V_6M). FIG. 3 also shows the indicia therefor. Indicia V1, V2, V3, and V4 indicate a single position for each of the V₁, V₂, V₃, and V₄ sensors. Indicia V5S indicates V₅ small; V5M indicates V₅ medium, V5L/V6S indicates either V₅ large or V₆ small. V5XL/V6M indicates either V₅ extra large or V₆ medium. V6L and V6XL correlate to V₆ large and extra large, respectively.

[0066] FIG. 4 shows the ten-sensor array for right chest ECGs which are the mirror image of the left chest array. The indicia are the same and differentiated from the left chest indicia by an additional R designation. The array includes, like the left chest array, singular VR₁, VR₂, VR₃, and VR₄ sensor positions and four alternate V₅ and VR₆ sensor positions. The VR₅ and VR₆ positions each have two independent sensor positions (VR_5S, VR_5M, VR_6L, and VR_6XL) and share two positions (VR_5L/VR_6S and VR_5XL/VR_6M). FIG. 4 also shows the indicia therefor. Indicia VR1, VR2, VR3, and VR4 indicate a single position for each of the VR₁, VR₂, VR₃, and VR₄ sensors. Indicia VR5S indicates VR₅ small; VR5M indicates V₅ medium, VR5L/VR6S indicates either VR₅ large or VR₆ small. VR5XL/VR6M indicates either VR₅ extra large or VR₆ medium. VR6L and VR6XL correlate to VR₆ large and extra large, respectively. The S, M, L, and XL indicia are provided to aid in selecting which set of sensors are to be utilized. The additional indicia between VR1 and VR2, and VR6M and VR6L, aid the user in positioning the mask.

[0067] FIGS. 1-4 are illustrations of sensor array masks which are printed on one side of a base layer sheet. The right chest masks and the left chest masks can be printed on the opposite or reverse sides of the same base layer or, as shown in FIG. 5, on opposite sides or the opposed ends of the same side of the base layer. In other words, the definition of the term “opposite sides” as used in the claims means either the reverse sides of the same sheet or opposing sides or ends of the same side of a sheet. When the masks are printed on both sides of a base layer, one side includes the V (left) sensor positions and the reverse side includes the VR (right) sensor positions. When the masks are printed on the same side of the base layer, one half or end includes the V (left) sensor positions and the opposed or other end includes the VR (right) sensor positions.

[0068] In the following description of the present invention and in the claims appended hereto, the opposite mirror image sides of the mask can be described concurrently. Each time a left chest sensor position or indicia is mentioned, the corresponding right chest designator follows in parentheses so that both sides are described concurrently. The same is true for the value designators for distance and angularity associated with the sensor positions where they are differentiated.

[0069] Nine or ten sensors 15 are arranged in a precordial sensor array of three or four sets of six sensors each in which certain of the sensors serve the same function in each of the three or four size sets of six, and at least one of the sensors serves as different designated sensors in the four different sets. If only three different sizes are provided on the mask, only nine precordial sensors need be provided as shown in FIGS. 1 and 2. In order to accommodate an extra large size chest, a set of ten precordial sensors are required as shown in FIGS. 3 and 4. FIG. 5 shows the FIGS. 1 and 2 for a three-sizes mask in a wings configuration with both the left chest and right chest masks on the same side of the base layer. The mask for fitting four sizes of persons as illustrated in FIGS. 3 and 4 would be identical except expanded to include the additional sensor positions and applicable indicia.

[0070] The nine or ten precordial sensors are disposed in a specific universal geometric arrangement rather than in predetermined fixed arrays of individual classes of sizes of sensor groups, as taught in the related cases and the Kelly and Manoli patents, or in multiple all-inclusive sensor group arrays as taught by the Stratbucker singular patent. Nor are they positionable in an arbitrary individually located array of six precordial sensors as would be placed by a technician for a resting ECG. In the present invention, nine sensors form three sets of sensor groups including three positions for each of the V₅ and V₆ (VR₅ and VR₆) positions in which one sensor position serves for either V₅ or V₆ (VR₅ or VR₆) in two different sensor sets whereby three sets of six sensors each are provided by the nine sensors to position six of the sensors proximate to the anatomical landmarks of three different classes of human torso sizes.

[0071] Ten sensors form four sets of sensor groups including four positions for each of the V₅ and V₆ (VR₅ and VR₆) positions in which two sensor positions serve for either V₅ or V₆ (VR₅ and VR₆) in four different sensor sets whereby four sets of six sensors each are provided by the ten sensors to position six of the sensors proximate to the anatomical landmarks of four different classes of human torso sizes including extra large.

[0072] The sensor positions 15 are disposed on the flexible sheet 13 which is designed to adhere to a human torso so that the receptor sensors are located upon the precordial area of the chest and above the epigastric region of the abdomen. The flexible sheet can be essentially transparent except where it underlies the indicia. In those areas, it probably needs to be opaque so that the different indicia on opposite sides of the sheet are clearly legible.

[0073] The mask includes the self-explanatory indicia 33, 35 for determining if it is for left chest or right chest use and for aligning it on both the centerline of the patient's sternum and on the fourth intercostal space, respectively, whereby at least three or four sets of sensor positions on the mask, comprising six sensors each, can accommodate up to three or four different classes of human torso sizes, respectively, for either left chest or right chest ECGs. In addition to facilitating correct placement of the receptors on the precordial areas of the human torso, the indicia also provide for selecting the correct set of sensor positions for the torso size and show which sensors are to be used. Indicia 29, 31 for the electrical connections to the ECG machine are also essentially self-explanatory and are accordingly based on the selected torso size of the patient. The precordial indicia indicate which sets of sensors correlate to which torso size and that two of the sensors are shared or utilized for four classes of torso sizes but numbered as different designation sensor positions, V₅ (VR₅) or V₆ (VR₆).

[0074] When the electrodermal connectors are properly positioned for attachment to a patient, the position of the receptors at V₁ (VR₁) and V₂ (VR₂) are disposed to lie approximately on opposite sides of the patient's sternum at the fourth intercostal space as shown by the indicia 33, 35. The receptors at V₃ (VR₃) and V₄ VR₄) are attached over the ribs, with V₃ (VR₃) positioned approximately equidistant between V₂ (VR₂) and V₄ (VR₄), and with V₄ (VR₄) positioned approximately over the intersect of the fifth intercostal space and the left midclavicular line. The receptors at V₅ (VR₅) and V₆ (VR₆) are placed at the side of the torso so that V₅ is substantially midway between V₄ (VR₄) and V₆ (VR₆).

[0075] In positioning the array of receptors for the preferred embodiment of the present invention, it has been found that the distance between V₁, V₂, V₃, and V₄ (VR₁, VR₂, VR₃, and VR₄) can be consistent for all sizes of human torsos. The dimensions between V₁, V₂, V₃, and V₄ (VR₁, VR₂, VR₃, and VR₄) have been developed to accommodate nearly all adults within tolerances acceptable for the resting ECG. It has also been found that body placement for receptors V₅ and V₆ (V₅ and VR₆) vary depending on individual size. These variations are uniquely accommodated in one size mask by the present invention.

[0076] There is a novel method provided by the present invention for determining the proper size selection of electrode sets, i.e., for selecting six of the ten sensor positions for performing an ECG depending upon the torso size of the patient. The selection of the six sensors is ascertained by determining which one of the same designation sensor positions in each set lies closest to a selected precordial landmark whereby the set containing that closest lying position is selected as the set of six sensors to be utilized. As with V₁-V₄ (VR₁-VR₄), it has been determined that the distance from the V₄ (VR₄) sensor position to the V₆ (VR₆) sensor position determines the size of a patient. For the inventions disclosed in the prior related applications, the measurement of this distance is determined by having the applying technician measure, such as by using his/her thumb and the middle finger, the distance between the midclavicular line and the midaxillary line on the chest of the patient. This distance is then compared to a sizing scale to select the proper size of mask. The present invention, however, does not require any type of intermediate step to determine a patient's size. Rather, the mask is applied to the patient and a simple visual observation ascertains which of four V₆ (VR₆) sensors lies closest to the patient's midaxillary line to establish that patient's size and the selection of the corresponding sensor set.

[0077] The distance between V₄ to V₆ (VR₄ to VR₆), that is, the distance between the midclavicular line and the midaxillary line on the patient, varies within predetermined limits based on the size of the torso. For a small size, the distance between V₄ and V₆ (VR₄ to VR₆) can range from about 2.5 to 4.5 inches; for the medium size, the distance can range from about 4.0 to 6.0 inches; for the large size, the distance can range from about 6.0 to 8.0 inches; and, for the extra large size, the distance can range from 8.0 to 12.0 inches.

[0078] In the present invention, sensors V₁, V₂, V₃, and V₄ (VR₁, VR₂, VR₃, and VR₄) are positioned the same for all sizes of torsos. The center of V₁ (VR₁) is located on a point generally about 2.0 inches from the center of V₂ (VR₂) approximately on the 270 (90 for VR₁) degree radial from the center of V₂ (VR₂) wherein the radial is measured with zero degrees measured from north at the top of V₂ (VR₂). The center of V₄ (VR₄) is located on a point generally 3.5 inches from the center of V₂ (VR₂) approximately on the 125 (235 for VR₄) degree radial from the center of V₂ (VR₂). The center of V₃ (VR₃) is in line with V₂ and V₄ (VR₂ and VR₄) and is located on a point substantially between the center of V₂ (VR₂) and the center of V₄ (VR₄). The receptors V₅ and V₆ (VR₅ and VR₆) have four alternative positions each: all of the positions being disposed on the 90 degree radial from V₄ (270 degree radial from VR₄). The centers of the V₅ (VR₅) positions are located approximately 1.75, 2.5, 3.5, and 5.0 inches from V₄ (VR₄) and the centers of the V₆ (VR₆) positions are located approximately 3.5, 5.0, 7.0, and 10.0 inches from V₄ (VR₄) whereby the centers of both V₅ and V₆ (VR₅ and VR₆) which are both located approximately 3.5 and 5.0 inches from V₄ (VR₄) share a common sensor in different sets of sensors.

[0079] If the mask is single-sided for right chest ECGs only, then the sensor position V designations may not carry the VR indicia but simply the V indicia as for left chest masks. However, the two angular dispositions of V₂ and V₄ sensor position are decreased by 180 degrees and increased by 110 degrees, respectively. In other words, for a right chest mask the center of V₁ is located on a point generally about 2.0 inches from the center of V₂ approximately on the 90 degree radial from the center of V₂ wherein the radial is measured with zero degrees measured from north at the top of V₂. The center of V₄ is located on a point generally 3.5 inches from the center of V₂ approximately on the 235 degree radial from the center of V₂. The receptors V₅ and V₆ have four alternative positions disposed on the 270 degree radial from V₄. The distances between the sensor positions are the same as for the left chest masks.

[0080] The table below corresponds to the determined measurements for electrode placement which are all inherent in the present invention. It shows the preferred dimensional layout for V₅ and V₆ (VR₅ and VR₆) relative to V₄ (VR₄) for different sized torsos. Obviously, small variations in the lengths of the measurements are within the scope of the invention:

[0081]

	TABLE I
		V4-V5	V5-V6	V4-V6
	Size	VR4-VR5	VR5-VR6	VR4-VR6
	Small	1.75″	1.75″	3.5″
	Medium	2.5″	2.5″	5.0″
	Large	3.5″	3.5″	7.0″
	X-Large	5.0″	5.0″	10.0″

[0082] The distance between V₁ and V₂ (VR₁ and VR₂) is 2.0 inches, the distance between sternum centerline and V₄ (VR₄), along a horizontal line is 3.85 inches, and the distance between V₂ and V₄ (VR₂ and VR₄) along a vertical line is 2.0 inches, although this vertical distance could be up to 3.5 inches without considerably altering the effectiveness of the mask. In addition, V₃ (VR₃) is located on a diagonal line between V₂ and V₄ (VR₂ and VR₄), and is equidistant from V₂ and V₄ (VR₂ and VR₄). These variations can be combined to create a universal mask by the use of only ten sensors to accommodate practically all adult sizes of torso.

[0083] The mask of the present invention provides a plurality of connectors or terminals arranged in a predetermined dimensional array V₁-V₆ (VR₁-VR₆) on the flexible sheet which inherently observes the dimensions dictated by Table I. In providing alternative locations of the sensors, the dimensional array on the flexible sheet becomes universal and the specific size configuration of the dimensional array or layout on the flexible sheet is determined in the same maimer as for multiple sizes of masks to permit the production of an accurate electrocardial recording during ECG testing which can be reliably repeated.

[0084] The nine or ten sensors are positioned on the sheet in a geometric pattern approximating the standard precordial anatomical landmarks of any adult human being. The positioning of sensors V₁-V₄ (VR₁-VR₄) is the same for all sizes of torsos and is shown in FIGS. 1 to 4 as V1, V2, V3, and V4 (VR1, VR2, VR3, and VR4). The V₅ and V₆ (VR₅ and VR₆) positions each have three or four alternate positions including two independent sensor positions each: V5S and V5M (VR5S and VR5M) for V₅ (VR₅) in both the three and four sensor set masks, and V6M and V6L (VR6M and VR6L) in the three set mask, and V6L and V6XL (VR6L and VR6XL) in the four sensor set mask for V₆ (VR₆). They also have one or two shared positions: V5L/V6S (VR5L/VR6S) for both the three and four sensor set masks and V5XL/V6M (VR5XL/VR6M) for the four sensor set mask. All of the V₅ and V₆ (VR₅ and VR₆) sensor positions lie along the same line with, and are spaced from, the V₄ (VR₄) sensor.

[0085] When the mask is utilized for a small size torso, the first independent V₅ (VR₅) alternate sensor position V5S (VR5S), disposed closest to the V₄ (VR₄) sensor position V4 (VR4), is utilized along with a first shared V₅ and V₆ (VR₅ and VR₆) alternate sensor position V5L/V6S (VR5L/VR6S) which of the V₆ (VR₆) positions is also disposed closest to the V₄ (VR₄) position.

[0086] When the mask is utilized for a medium size torso, the second independent V₅ (VR₅) alternate sensor position V5M (VR5M) is utilized along with the V6M (VR6M) position in the three sensor set mask or the second shared V₅ and V₆ (VR₅ and VR₆) alternate sensor position V5XL/V6M (VR5XL/VR6M) position in the four sensor set mask.

[0087] When the mask is utilized for a large size torso, the first shared V₅ and V₆ (VR₅ and VR₆) alternate sensor position V5L/V6S (VR5L/VR6S) is utilized along with the first independent V₆ (VR₆) alternate sensor position V6L (VR6L).

[0088] When the mask is utilized for an extra large size torso, the second shared V₅ and V₆ (VR₅ and VR₆) alternate sensor position V5XL/V6M (VRXL/VR6M) is utilized along with the second independent V₆ (VR₆) alternate sensor position disposed furthest from the V₄ (VR₄) sensor position.

[0089] The first and second shared V₅ and V₆ (VR₅ and VR₆) sensor positions function either as the V₅ or V₆ (VR₅ or VR₆) positions depending upon the size of torso the sensor mask is being utilized on. When the mask is utilized for a small and large-size torsos, the first shared V₅-V₆ (VR₅-VR₆) position functions as V₆ or V₅ (VR₆ or VR₆), respectively. When the mask is utilized for a medium and extra large-size torso, the second shared V₅-V₆ (VR₅-VR₆) position functions as V₆ or V₅ (VR₆ or VR₅), respectively.

[0090] The sensor set selected for performing the ECG on a specific patient is recorded for the taking of subsequent ECGs on that patient to insure repeatability of sensor placement.

[0091] The present invention also contemplates a method for sensor placement for performing electrocardiographic recording, and a method of sensor placement for performing twelve-lead electrocardiograms on either the left chest or the right chest, by means of a universal ECG multiple sensor dermal precordial mask incorporating sensors V₁, V₂, V₃, V₄, V₅, and V₆ (VR₁, VR₂, VR₃, VR₄, VR₅, and VR₆). The mask is formed for fitting or accommodating up to four different sizes of human bodies including extra large with repeatability and clinical efficacy of sensor positions V₁, V₂, V₃, V₄, V₅, and V₆ (VR₁, VR₂, VR₃, VR₄, V₅, and VR₆) placement irrespective of the varying human body torso sizes and the different distances between the human body anatomical landmarks.

[0092] The method of sensor placement is comprised of several steps. A mask is provided which is formed for clinically efficacious placement of six precordial sensors on a patient's chest irrespective of torso size. The mask has a multiplicity of precordial sensor positions disposed in a specific geometrical pattern rather than in predetermined fixed arrays of individual sensor groups or an arbitrary individually located array of six precordial sensors. As few as nine sensors can be utilized to serve as sensors for at least three different classes of human torso sizes. The addition of only one sensor position permits the mask to accommodate four different classes of human torso sizes including extra large.

[0093] In the preferred method of the invention, the mask is provided with an arrangement of at least nine precordial sensor positions which are arranged in or form at least three sets of sensor groups of six sensors each. Certain of the sensor positions serve the same function in each of the sets, and at least one of the sensors serves as a different designated sensor in different sets. In the preferred embodiment of the invention, ten precordial sensor positions are provided which are disposed on opposite sides of the mask in a specific geometric mirror image arrangement forming four sets of sensor groups with the V and VR positions disposed on opposite sides of the mask. Each side includes four alternate sensor positions for each of the V and VR sensor positions. The V₁-V₄ (VR₁-VR₄) positions are utilized for all four sizes of bodies. In all four groups, two sensor positions serve for either V₅ or V₆ (VR₅ or VR₆) in the four different sensor sets whereby four sets of six sensor positions each are provided by the ten sensor positions to locate six of the sensors proximate the standard precordial anatomical landmarks of four different classes of sizes of human torsos.

[0094] The ten sensor positions are disposed on opposite sides of the mask forming four sets of sensor groups including three alternate positions for each of V₅ and V₆ (V₅ and VR₆) in which two sensor positions serve for either V₅ or V₆ (VR₅ or VR₆) in four different sensor sets whereby four sets of six sensors each are provided by the ten sensor positions to position six of the sensors proximate to the anatomical landmarks of four different classes of sizes of human torsos.

[0095] The mask is provided with indicia for determining whether it is for left chest or right chest use and for positioning it on a patient's sternum centerline and the fourth intercostal space and for determining which sensor positions correspond to the four sensor sets.

[0096] The mask applicator selects which side of the mask corresponds to the side of the patient's chest that the ECG is intended to record. The masks which have sensors printed on both sides thereof cover one side of the chest, and when the mask is utilized for a left chest ECG recording one side of the mask is utilized, and when the mask is utilized for a right chest ECG recording the reverse side of the mask is utilized. The masks which have sensor positions printed on one side thereof cover the whole chest, and when the mask is utilized for a left chest ECG recording one half of the mask is utilized, and when the mask is utilized for a right chest ECG recording the other half of the mask is utilized.

[0097] The mask is placed on a patient's chest and the positioning indicia on the mask are aligned with the corresponding anatomical positions on the patient's chest so that V₁ and V₂ (VR₁ and VR₂) are disposed approximately on opposite sides of the patient's sternum at the fourth intercostal space. Six of the ten sensor positions are then selected for performing an ECG depending upon the torso size of the patient by determining which one of the same designation sensors in each set lies closest to a selected precordial landmark whereby the set of sensors containing the closest lying sensor is selected as the set of six sensor positions to be utilized. In the preferred embodiment of the invention, this is done by ascertaining from the mask's indicia which of the four V₆ (VR₆) sensor positions lies on or closest to the patient's midaxillary line.

[0098] Sensor leads from ECG test apparatus are connected to the corresponding set of sensors which include the identified V₆ (VR₆) position, and electrocardiographic information is obtained from those sensors.

[0099] Thus, in summary, both an apparatus and methods for torso sizing and sensor placement for performing twelve-lead electrocardiograms for either left chest or right chest recording are provided, and the stated objects of the present invention are achieved. A single mask design, having only ten sensors on either side of the mask, instead of three or four different sizes of masks, as taught by the prior art, provides a universal size which can be utilized to obtain the benefits of simplified high volume production in order to lower the cost to the user and reduce the time previously needed to establish the size of a patient. The preferred embodiment of the present invention solves the problems associated with high variability of individual sensor placement which may produce inaccurate ECGs, and thus an incorrect diagnosis, and which problems prevent valid and reliable serial comparisons between repeat ECGs on the same patient.

[0100] The present invention eliminates the logistics of maintaining different size sensor masks and left and right chest inventories. This includes the stock in the central supply of a hospital, stock rooms of wards and clinics, and individual ECG carts. A related benefit is that stock would be depleted evenly thereby eliminating the possibility that some stock, e.g., a less often used size in a four-size system, might not be used prior to reaching an expiration date. The one size design of the present invention eliminates the steps required to determine a patient's torso size and fits ninety-nine percent (99%) of both the left and right sides of the chest of the adult torso population including extra large. Any possibility of error when sizing a patient is eliminated.

[0101] The method of the present invention is one in which there is less waste since essentially all adult patients and teenagers are accommodated by the one mask. With more than one mask size, there is the possibility that a wrong size would be applied to a patient and would need to be removed and discarded prior to applying the correct size mask. This trial and error situation would also increase the time spent performing an ECG on one patient. This is eliminated by the present invention.

[0102] The mask and method of use of the present invention in which the additional sensors with their respective adhesive areas increase the total area adhered to the patient. This will reduce the tension on each individual sensor since any pulling caused by respiration or from the ECG cable assembly will be shared by a greater number of sensors than would exist with a six-sensor precordial pad. It is generally understood that too much tension on a sensor decreases its performance.

[0103] It is also an object of the present invention to permit the taking of four different ECGs simultaneously with the same mask on either the left or right chest. Because the mask contains four precordial sensor patterns, it is possible to take four different ECGs by connecting to each pattern in turn by simply reapplying the single six-conductor connectors serially to the four terminal sets. This may provide additional diagnostic information beyond what is now obtained from a conventional ECG using six precordial sensors.

[0104] Thus, it will be apparent from the foregoing description of the invention in its preferred form that it will fulfill all the objects and advantages attributable thereto. While it is illustrated and described in considerable detail herein, the invention is not to be limited to such details as have been set forth except as may be necessitated by the appended claims.