**4.1 SP2000**

146 Modern Telemetry

Fig. 1. Picture and schematic drawing of a newly developed telemetry system for recording

The implantable transmitter consists of a hermetically sealed plastic housing with a biocompatible silastic coating, occupying a volume of less than 1.9 ml and weighing approximately 3.8 g. Each transmitter contains an amplifier, a battery, radio-frequency electronics, a pair of flexible leads with 20 cm and a magnetically activated switch which allows the device to be turned on and off either *in vivo* or *ex vivo*. The transmitter passes the ECG signal to a receiver located beneath the animal cage via radio signal. The data acquisition system records and stores the raw telemetered data into the hard disk for

In many studies, the typical implantation procedure for monitoring ECG is positioning the body of the transmitter in the peritoneal cavity of the laboratory animals. However, we usually implant a telemetry transmitter for ECG chronically into the notal subcutanea under pentobarbital sodium anesthesia (40 mg/kg, intraperitoneally), because this procedure can easily perform and much less invasive and/or damaged for laboratory animals than in the peritoneal cavity procedure. Before making the incision in the skin of the animal, we use a clipper to remove the hair from the operation area of the anesthetized animal. The animal is placed on a hot plate to avoid hypothermia during procedure, and the operation area is sterilized with iodine. A 1.0-1.5 cm long incision in the skin is made, and transmitter is implanted into the subcutaneous area as shown in Fig. 2. Both electrodes are situated in the direction of the head of the animal. Paired electrodes of the transmitter are placed under the skin of the dorsal and ventral thorax to record the apex-base (A-B) lead ECG. When both electrodes are fixed on their places, the transmitter is activated by a magnet close to the transmitter body. When the battery of the transmitter is switched on, the heart beats are clearly audible within a few seconds. To complete the operation, the incision of skin is

**4. Software for recording and analyzing of ECG from many points of view** 

Softron ECG processor can connect to a telemetry receiver as well as a bioelectrical amplifier, a data recorder and a Holter ECG recorder for recording and analysis of ECGs. Many useful softwares are provided to record and analyze ECGs. In this section, I introduce

ECGs. A telemetry transmitter is on a telemetry receiver.

subsequent analysis as described below (Section 4).

closed with absorbable suture or Michel clips.

these softwares.

**3. Transmitter implantation** 

SP2000 consists of the acquisition program and basic analyzing program for ECGs. The acquisition program can collect the data for a specific length of time or continuously and save it on the computer's hard drive. The acquisition program consists of a Config, WaveIn, Replay, Edit, Print etc as shown in Fig. 3.

Fig. 3. Main menu (left) and WaveIn screen (right) of SP2000.

The Config (Configulation module) allows users to create a file that contains settings for detecting and collecting data signals during a study and to modify an existing configuration file for use in a different study. To record ECG waves, WaveIn is opened after setting of configulaton. The analyzing program calculates the points and characteristic values of an

Recent Advances in Telemetry Monitoring and Analysis for Laboratory Animals 149

Fig. 5. Long term ECGs of mouse represent with SHL-2W window.

Fig. 6. Print preview window of compress ECGs.

ECG: characteristic points of the P, Q, R, S, T waves as well as the time intervals between these different points by Edit screen as shown in Fig. 4. The program can operate in automatic detection of complexes directly from the ECG signal. This detection is based on the presence of a R wave peak.

Fig. 4. Edit screen of a mouse ECGs.
