Methodology: Automated monitoring and the analysis of running distance for more than 30 animals simultaneously proved to be very easy and reliable. Twice daily inspections of cages were sufficient to prevent food from blocking the wheel, something that could occasionally occur. The procedure for transmitter implantation proved to be very simple and safe, as long as CM hamsters were under the age of 220 days or before signs of cardiac dysfunction developed. Several hamsters resumed normal running the night following the procedure (ie, 8 to 10 h after surgery) and infection did not occur. The transmitter battery can be turned on and off as required simply by touching the hamster’s abdomen with a magnet. Therefore, even if the battery life is only approximately five months, the implantation may be performed when the animal is young and able to sustain the procedure, and the ECG recording may be started much later when required. In general, ECG signals, if sampled at high frequency, were of excellent quality and allowed semiautomatic analysis of heart rate. However, on many occasions, particularly during running, we observed distorted signals that precluded any attempt to calculate heart rate. This was the major limitation to automatic heart rate analysis by Dataquest, which provides only numerical output, without the possibility of viewing the analyzed ECG signal. We found that heart rate determination using DADISP software was a much better approach since the actual ECG signals could be viewed and edited before the heart rate was determined. The major limitation to long term (ie, months-long) monitoring of many simultaneous ECGs (eg, 12 to 15hamsters) is the cost involved in storing data. Existing optical disks, which are expensive, can store 500 Mbytes/side of data, which is barely enough for a 22 to 24 h recording of 12 hamsters at 200 samples/s. Recent availability of affordable CD-ROM writers, which use much cheaper disks that can store 1.5 times as much data permanently, would provide more cost effective and increased efficiency of data storage. Having a pharmacy you can trust is now easy and available any time you need: Buy Xopenex Online to check and see how cheap your treatment could be while still being just as efficient and safe.