Biomedical Instrumentation

Archive for April, 2009

Dear friends! There are numerous types of ECG recorders are available. Many of these are portable units, while the others are permanent installations.  The types of recorders are discussed below:

Single Channel Recorders: The most frequently used type of ECG recorder is the portable single channel unit. For hospital use this recorder is usually mounted on a cart so that it can be wheeled to the bedside of a patient with relative case. If the electrocardiogram of a Patient is recorded in the twelve standard lead configurations, the resulting paper strip is form 3 to 6ft long. Even if folded in accordion fashion, the strip is still inconvenient to read and store. Therefore, it is usually cut up, and sections of recording from twelve mounted leads. Because it is easy to mix up the cut sections, the lead for each trace is encoded in the paper, using the marker pen, during the recording process. The code markers consist of short marks and the long marks and look similar to Morse code. No standard code has been established for this purpose, however. The cut sections of the electrocardiogram can be mounted by inserting them in pockets of a special folder with cutouts to make the trace visible. It should be noted that the recordings from the three limb leads are longer than those from the other lead selections in order to show several complexes, they are called as rhythm strips. Commercial systems are available to simplify the mounting by die-cutting the paper strip and using mounting cards with adhesive pads. With the automatic three-channel recorders mounting is greatly simplified.

Three Channel Recorders: Where large numbers of electrocardiograms are recorded and mounted daily, substantial savings in personnel can be achieved by the use of automatic three channel recorders. These devices not only record three leads simultaneously on a three-channel recorder, but they also switch automatically to the next group of three leads. An electrocardiogram with twelve standard leads, therefore, can be recorded automatically as a sequence of four groups of three traces. The time required for the actual recording is only about ten seconds. The groups of leads recorded and the time at which the switching occurs are automatically identified by code markings at the margin of the recording paper.  My dear friends! I am sure this article will enhance your knowledge regarding ECG recorders.