Universal Mapping FAQ's

What's cardiac electrophysiological mapping?

Gallagher defined cardiac mapping as "a method by which potentials recorded directly from the surface of the heart are spatially depicted as a function of time in an integrated manner. The location of recording electrodes (epicardial, intramural, or endocardial), the recording mode used (unipolar vs. bipolar), as well as the method of display (isopotential vs. isochrone maps) depends upon the problem under consideration." Universal Mapping goes a little bit farther than this for it can also analyze fluorescent signals emitted by potential-sensitive dyes such as di-4-ANNEPs and other kinds of maps such as derivative maps of potential. In addition Universal Mapping can create moving displays of potential and first derivative of potential, too.

What's wrong with your current mapping software?

Traditional programs for the display and analysis of multi-channel mapping data typically suffer from several of the following limitations:

  1. Implementation in a low-level language, which makes source code laborious to write and difficult to maintain
  2. Restriction to a specific mapping system and a single type of mapping data (such as unipolar electrograms)
  3. rigid user-interface, with either a cryptic command-line or an inflexible menu hierarchy
  4. inflexible display engine: just one or two views of your data at any one time
  5. lack of documentation.

What's so different about Universal Mapping?

Universal Mapping avoids the above-mentioned 5 limitations of traditional mapping programs:

  1. The program is implemented under Research Systems, Inc. IDL 4.0.1, which provides all the medium-level building block for building powerful graphical applications. The initial program development time was only 4 weeks, and so far the code, which since went through many incremental stages of development, has proved to be easy and straightforward to maintain.
  2. The program is "universal", i. e. mapping-system independent, allowing up to 9999 channels in any arrangement on the screen, and . Algorithms can analyze unipolar and bipolar electrograms and optical action potentials.
  3. The user interface is fully graphical with no modal dialogs that would impose needless restrictions on the user.
  4. The program can, on the same screen, display a selected single signal, a map of all signals, color-coded, contour and movie maps of activation, repolarization and action potential duration, potential distribution and first derivative of potential. A mouse click on any of these maps will update the single-signal window with the selected channel.
  5. The program is fully documented on over 30 pages of documentation. There is even support.

What is "universal" about Universal Mapping?

The mapping-system independent design. Universal Mapping is designed to be hardware and mapping system independent from the ground up. Therefore, Universal Mapping can:

What does the program cost?

Currently, Universal Mapping is available for free. Contact the developer for the software evaluation agreement, sign the agreement and send or fax it back to receive the distribution archive with software and documentation.

Where's the catch?

How do I install the program?

Where can I get support?

Do I have to dump my old data?

No, Universal Mapping can read them all. Once you have worked out the correct settings for the import of your existing data files (or anybody else's data files), you can save them to disk and re-use them. If you contact the developer and send him a sample file with documentation and a print-out of your data your import filter can even be included in the next release of Universal Mapping.

What happens if I ever get a new mapping system?

No problem, Universal Mapping will be able to read your data.

What happens if I get a new mapping electrode array?

No problem, all you need to do is to write a new matrix file for the display of your data by Universal Mapping. Take an existing matrix file and open it with a text editor. Update the number of rows and columns of channels that you want to be displayed on the screen. Then list the channel numbers one by one as they are to be arranged on the screen, starting with the left upper corner of the screen. Assuming you have n data channels, the number for the first channel is 0 and for the last channel is n-1. Encode external data channels by negative numbers (if 0 is an external channel, it will be -1, 1 will be -2 and so on until -n for the last channel) and missing channels by the number 9999. Assign a code to each thumbnail plot on the screen. Save your work as an ANSI file under a new file name with the extension ".OMX" and you are done. The process of generating matrix files can be considerably speeded up if you set up the codes in a spreadsheet program, using their built-in drag and copy functions, and export the values in the spreadsheet as a space-delimited text file and add a header from an existing OMX file.

What happens if I need a new module for some special task?

As the full version of the program includes the source code, you can write the code yourself if you want to. Alternatively, you can ask the developer to write it for you.

What kind of a mapping system do you use?

My mapping system is set up for recording fluorescent signals emitted by isolated cardiac preparations that are vital-stained with potential-sensitive dyes such as di-4-ANEPPs. My mapping system is more or less entirely based on the laboratory designed by Igor Efimov at the Cleveland Clinic Foundation with the exception that I am using the amplifier circuits developed by Vladimir Fast at the University of Bern/Switzerland. The centerpiece of the system is a 16 x 16 element Hamamatsu photodiode array, which comes with 256 built-in current-to-voltage converters in a neat enclosure. Each of the 256 signal channels is then individually amplified with a user-selectable gain and then passed to a MicroStar Laboratories acquisition board, which performs the analog-to-digital conversion.

Is there a data acquisition module?

Yes, there is, and it is available from the developer as a free add-on to the Universal Mapping program. The mapping data display and analysis program Universal Mapping was designed to be mapping-system independent from the ground up. That's why the developer decided to implement his data acquisition program, which is by necessity highly dependent on the underlying hardware, as a separate task completely independent of the Universal Mapping program. It is even programmed on a different platform, National Instruments LabView 4.0.1 which provided easy access to National Instrument's digital timer board. The data acquisition program has a fully graphical user-friendly interface and includes a fully-featured programmable stimulator (up to three premature stimuli, a forth premature stimulus from a second output channel) and freely configurable timing pulses for the control of an optical mapping system (one pulse for the electric shutter of the light source to protect the preparation from photobleaching and phototoxicity, one pulse for the control of the offset subtraction of the amplifiers and a third pulse to trigger data acquisition by the analog to digital conversion board.) You can have the data acquisition program, but no support can be provided for this particular program.

Can Universal Mapping interact with my own data acquisition software?

Yes, it can. Any external data acquisition program can communicate with the Universal Mapping mapping data analysis program. All that the data acquisition program has to do is to prefix the binary data file with Universal Mapping's ANSI file header. The ANSI file header can contain all kinds of information on the data file, such as the number of data channels, the sample rate, the amplifier gain(s), the matrix file to be loaded by Universal Mapping defining the arrangement of the data channels on its screen, time and date of the recording, the stimulation protocol at the time of the recording, a comment on the experimental protocol and many more. To prompt Universal Mapping to read the latest data file, just let your data acquisition program write a dummy file called AUTOLOAD.TXT into the data directory, and Universal Mapping will automatically open the latest data file, read its file header and load and display the data according to the information found in the file header.

Do I have to use Windows NT?

No. The same version of IDL also runs under Windows 95. However, I strongly advise users to upgrade to Windows NT 4.0 (Service Pack 1 - don't try Service Pack 2), which is a rock-solid multitasking operating system. I don't say that there aren't some nasty programs that can lock up an NT machine, but once you got your NT system set up with decent software, crashes of NT will be as rare as 286-computers running MS Windows 1.0. If you are planning to do serious experiments - as I hope you do - you don't want your lab computer to lock up any minute while the arrhythmia that you set out to map occurs and can't be re-induced. This once happened to Igor Efimov and it steeled his resolve to port his data acquisition to Windows NT.

Windows NT is fine, but what happens if I ever switch to a new OS?

No problem, Research Systems, Inc. IDL supports essentially every operating system on any hardware platform currently available (e. g. NT both on Intel and on Alpha, Mac OS, all major UNIX flavors including LINUX) with the exception of IBM OS/2. Should NT fall in disuse, IDL will be sure to support your next platform of choice. The platform-specific code in Universal Mapping is kept to a minimum and clustered in a few routines that can easily be adapted to the new environment. The only thing that's bound to happen is that IDL will run even faster!

What if all this didn't answer my questions?

Just contact the developer and try out the program for yourself.

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