K972991 · Qmed, Inc. · DPS · Dec 3, 1998 · Cardiovascular
Device Facts
Record ID
K972991
Device Name
MONITOR ONE NDX
Applicant
Qmed, Inc.
Product Code
DPS · Cardiovascular
Decision Date
Dec 3, 1998
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 870.2340
Device Class
Class 2
Indications for Use
The monitor one nDx® is intended to measure time domain heart rate variability (HRV) in response to a series of standardized, controlled exercises on the patient. While the monitor one nDx® has been shown to be safe and effective for the measurement of heart rate variability, it is not intended to be used as the basis for a specific clinical diagnosis. The clinical significance of HRV should be determined by the physician.
Device Story
Hand-held, battery-powered ECG monitor and respiration pacer; captures ECG signals via skin electrodes (V5 lead configuration). Device conditions signals using instrumentation amplifiers and filters; converts analog signals to digital (256 Hz sampling). Microprocessor applies statistical analysis to stored beat times to measure heart rate variability (HRV) during paced breathing, Valsalva maneuver, and posture tests. Output provided as printed or electronic data for physician review. Used in clinical settings; operated by healthcare providers. Provides diagnostic aid for cardiac function assessment; does not provide diagnosis. Benefits include standardized, non-invasive assessment of HRV to support clinical decision-making.
Clinical Evidence
No clinical data provided. Bench testing only, including verification of signal processing, digital sampling (256 Hz), and computational accuracy of HRV metrics.
Technological Characteristics
Microprocessor-based, hand-held, battery-powered (4 AA alkaline). 3-lead ECG sensing; instrumentation amplifier; analog-to-digital converter (10-bit resolution @ 256 Hz). Infrared optical link for data transmission. Solid-state design; no motors or fluid systems. Includes tone generator and LCD. Pre-gelled, self-adhesive electrodes.
Indications for Use
Indicated for patients undergoing standardized, controlled exercises (paced breathing, Valsalva maneuver, posture test) to assess heart rate variability. Not intended for specific clinical diagnosis.
Regulatory Classification
Identification
An electrocardiograph is a device used to process the electrical signal transmitted through two or more electrocardiograph electrodes and to produce a visual display of the electrical signal produced by the heart.
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K972991
510(k) SUMMARY
# Monitor One nDx®
# 510(k) SUMMARY AS REQUIRED BY ¶807.92(c)
| Prepared by | Joseph Hanna, Director of Quality Assurance |
|------------------------------|---------------------------------------------------|
| Date of Preparation | July 1997 |
| Company | qmed Inc. |
| Company Address | 100 Metro Park South<br>Laurence Harbor, NJ 08878 |
| Company Telephone | 800-237-2039 |
| Company Fax | 908-566-0912 |
| Contact Person | Joseph Hanna |
| Address for Contact Person | qmed Inc.<br>60 Bay Street<br>Sag Harbor NY 11963 |
| Telephone for Contact Person | 516-725-2345 |
| Fax for Contact Person | 516-725-7495 |
| Device Name | monitor one nDx® |
| Common Name | ECG monitor and respiration pacer |
| Classification | Class II |
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.
# Section 01
# 510(k) SUMMARY
### Table of Contents
| | | 1. DEVICE IDENTITY | |
|----|------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--|
| | 1.1. | TRADE NAME…………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… | |
| | 1.2. | COMMON NAME | |
| | 1.3. | CLASSIFICATION NAME | |
| | | 2. DESCRIPTION OF THE DEVICE | |
| 3. | | SPECIFICATIONS | |
| | 3.1. | ELECTRODES | |
| | 3.2. | ELECTRODE CABLE | |
| | 3.3. | COMMUNICATIONS INTERFACE | |
| | | 4. INTENDED USE/INDICATIONS FOR USE | |
| 5. | | PREDICATE DEVICE | |
| 6. | | SAFETY SUMMARY | |
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### 510(k) SUMMARY
#### DEVICE IDENTITY 1.
#### TRADE NAME 1.1.
monitor one nDx®
#### COMMON NAME 1.2.
ECG monitor and respiration pacer
#### CLASSIFICATION NAME 1.3.
Electrocardiograph (Product code DPS)
#### 2. DESCRIPTION OF THE DEVICE
monitor one nDx® is a microprocessor based, real-time, hand-held, battery powered, ECG monitor and respiration pacer.
It identifies, classifies, analyzes, stores and retrieves from memory electrocardiographic (ECG) signals for the purpose of measuring and providing statistical analysis of heart rate variability. These signals, along with associated numerical data, are provided to the user in printed or electronic form for over-reading by competent medical professionals.
The monitor one nDX ® system consists of a pacing and recording device, a set of skin electrodes with associated cable and an optically coupled interface for transmitting stored data to compatible devices or modems
The hand-held monitor weighs 16 oz. and measures 7.5 x 3.5 x 1.4 inches. It is powered by four AA alkaline batteries.
monitor one nDx® senses changes in the electrical potential of the skin caused by successive depolarization and repolarization of the heart as it beats. These electrocardiographic (ECG) signals are picked up by electrodes applied to the skin in three locations representing two poles of the V5 lead (recommended) and a reference or "ground" lead. The resulting signal is fed to a series of operational amplifiers, comprising a precision instrumentation amplifier. The signal is conditioned, by means of filters to minimize the effect of noise and artifact. Protection circuits shunt destructive overvoltage to ground to prevent damage to the circuitry.
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### 510(k) SUMMARY
An analog-to-digital converter samples the amplified signal at specific intervals timed by the system master clock and converts the instantaneous voltage to a numeric value is passed to the microprocessor.
Measurements of signal features, the instantaneous value of the signal for each time sample, results of algorithm operations and information about the state of the monitor and its subsystems are stored continuously.
A clock and calendar timer provides the processor with the actual time and date.
The microprocessor has been programmed to apply statistical analysis to the list of stored beat times. The results are both displayed and/or printed out for review by the attending physician.
A buffered interface can receive data from the monitor and pass the data to either a local printer or a modem.
Image /page/3/Figure/10 description: This image shows a block diagram of a single-channel system. The diagram includes several components, such as electrodes, an amplifier (Amp), an analog-to-digital converter (A/D), a microprocessor, and a VIA (Versatile Interface Adapter). Other components include a keyboard, display, audio, optical serial port, power management, EPROM, RAM, and a time and date clock.
### monitor one nDx Block Diagram
Figure 1-A
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## 510(k) SUMMARY
### SPECIFICATIONS 3.
montor one nDx® is a portable ECG monitor that has been programmed to provide timing cues to enable a patient to synchronize both respiration cycles and other exercises to a standard regimen used to assess heart rate variability.
The device weighs slightly less than a pound. It has three controls operated by the user: an on/off switch, a twelve (12) button key pad and a pushbutton.
Image /page/4/Picture/8 description: The image shows three views of a handheld device. The first view is a front view, which shows a screen, a keypad, and a few other buttons. The second view is a side view, which shows a port. The third view is a back view, which shows two compartments.
Figure 1-B
The device includes a tone generator and a liquid crystal display (LCD). It uses an infrared optical link to transmit data to the interface, providing complete electrical isolation for the patient.
The device is programmed with three different protocols to aid in assessing heart rate variability; paced breathing, the Valsalva maneuver and a posture test.
The device stores a complete test series composed of a single paced breathing test, three Valsalva results and a posture response for each patient. The data may be erased after review or stored in memory indefinitely. All data must be erased before a new patient is tested.
The digital sampling rate is 256 samples per second. The digital resolution is 10 bits @ 256 Hz. The range of normal QRS is between 50-120 milliseconds.
#### 3.1. ELECTRODES
Electrodes supplied with the device are 510(k)-cleared. These are pre-gelled, self-adhesive electrodes.
#### 3.2. ELECTRODE CABLE
The cable is a plastic-jacketed, shielded cable terminated at one end by a mechanically polarized connector with recessed pins and terminated at the other end by a plastic break-out from which radiate individual shielded lead wires which themselves are terminated by standard medical snap connectors for attachment to electrodes.
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### 510(k) SUMMARY
### COMMUNICATIONS INTERFACE 3.3.
A device which receives formatted serial data from the monitor, and which has the capability to store the data or convert it to parallel data format for redirection to a printer or modem. The communications interface consists of the following components:
- Plastic case with folding support; .
- 6 labeled keys; .
- 3 bi-color enunciator LEDs (labeled); .
- . Serial optical link;
- Low voltage power jack; .
- Nicad battery memory back-up; .
- 6552 microprocessor; .
- 25 pin D connector; .
- Printed circuit board; and .
- . Assorted electronic parts.
#### 4. INTENDED USE/INDICATIONS FOR USE
The monitor one nDx® is intended to measure time domain heart rate variability (HRV) in response to a series of standardized, controlled exercises on the patient. While the monitor one nDx® has been shown to be safe and effective for the measurement of heart rate variability, it is not intended to be used as the basis for a specific clinical diagnosis. The clinical significance of HRV should be determined by the physician.
#### 5. PREDICATE DEVICE
For statistical analysis of heart rate variability, the monitor one nDx® is substantially equivalent to the SpaceLabs Heart Rate Variability Software Option (K950779) that was determined to be SE April 25, 1995.
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## 510(k) SUMMARY
#### SAFETY SUMMARY દ.
qmed is not aware of any adverse safety information pertaining to the use of the monitor one nDx®. The following points are relevant.
- There are no plausible conditions in which the device could immediately threaten a patient's life. The . device itself operates on four penlight batteries. The combination of high resistance input and passive protection circuitry insures that potentially harmful electrical current cannot be applied to the patient even in the event of system failure or physical damage.
- . The device cannot directly cause irreversible illness or permanent injury under any plausible conditions. The device is non-invasive, and does not directly control any life sustaining systems or functions.
- The device does not directly control the delivery of energy, or the administration of parenteral drugs. ●
- The device is a diagnostic aid that presents information the physician uses, along with other important . indications, to assess certain aspects of cardiac function.
- . No special skills are needed to operate the device.
- The quality of the data is not dependent on operator skills.
- . The controls (keypad, power switch and pushbutton) do not initiate any mechanical action, do not mediate the delivery of any substance or energy, and are not associated with any alarm condition that could plausibly create a hazard of harm or injury to either the user or the patient due to malfunction or misuse.
- The electrode cable is terminated at the monitor end with a polarized unique plug assembly in which the . male contact pins are shrouded by nonconductive material. The design is such that the pins are not exposed to accidental contact with voltage sources. The form and dimensions of the plug are unique. The plug cannot be inserted in devices other than the intended device. The polarized design eliminates the possibility of inserting the plug in an improper orientation.
- . The device is solid state throughout. There are no motors, transport mechanisms, fluid or pneumatic storage systems.
- The device weighs less than a pound, is easily held in the hand, has no protruding or abrasive surfaces, will . not create hazardous particles when dropped, and may be stored indefinitely.
- . The device makes computations that are verified by a health care professional and does not provide a diagnosis.
End of section
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Image /page/7/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo consists of a stylized eagle or bird symbol, with three curved lines representing the bird's body and wings. The logo is surrounded by the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" in a circular arrangement.
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
DEC
Mr. Joseph Hanna gmed, Inc. 60 Bay Street Sag Harbor, NY 11963
Re: K972991 Monitor One nDx® Regulatory Class: II (two) Product Code: 74 DPS September 10, 1998 Dated: Received: September 10, 1998
Dear Mr. Hanna:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in requlatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.
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### Page 2 - Mr. Joseph Hanna
This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4648. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or (301) 443-6597, or at its internet address "http://www.fda.gov/cdrh/dsma/dsmamain.html".
Sincerely yours,
Thomas J. Callahan
Thomas J. Callahan, Ph.D. Director Division of Cardiovascular, Respiratory, and Neurological Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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510(k) Number (if known): K972991 Device Name: _______monitor one nDx __
The monitor one nDx® is intended to measure time domain heart rate variability (HRV) in response to a series of standardized, controlled exercises on the part of the patient. While the monitor one nDx® has been shown to be safe and effective for the measurement of heart rate variability, it is not intended to be used as the basis for a specific clinical diagnosis. The clinical significance of HRV should be determined by the physician.
### (PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED Concurrence of CDRH, Office of Device Evaluation (ODE)
OR
Name
Division Sign-Off)
Division of Cardiovascular, Respiratory,
and Neurological Devices
510(k) Number.
Prescription Use (Per 21 CFR 801.109)
Over-The-Counter Use
、・・
Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.