Pacemaker codes

TABLE 11.1 The NASPE/BPEG Generic (NBG) Pacemaker Code... 

TABLE 20.1 The five-position NASPE/BPEG Generic Pacemaker Code. The purpose of the code is to allow medical practioners to recognize the basic features and capabilities of a given pacemaker. The code alone does not provide a complete description of device features, but is clear and simple to use... 

There are various types of PPM that pace different chambers of the heart. The choice of pacemaker system used depends very much on the patient s condition and the underlying rhythm of the patient. Most systems are inserted in theatre or a cardiac catheterization lab using fluoroscopic imaging to position the leads, which are inserted through a vein (i.e. the cephalic or Subclavian vein). There are several different modes a pacemaker can be set to. To distinguish between these different settings pacemakers are given a code to define their type and function. Table 8.1 summarises these pacemaker codes. 

Yet under the original requirements of 21 CFR Part 11 both companies would have had to conduct extensive test on the software to write and implement eight to ten standard operating procedures to document the requirements, development, and change history of the code and to record and archive all records. In this case, as in so many, such an investment in time and dollars would have been justihed for the pacemakers but wasted in the case of the tongue depressors. 

Modern pacemakers use both read-only memory (ROM) and random-access memory (RAM). Although RAM provides the ability to store diagnostic data and change feature sets after implantation, the need to minimize device size and current drain keeps RAM typically on the order of tens of kilobytes in older devices. (Newer devices may have a megabyte or more.) ROM is less susceptible to data errors therefore, it is typically used to store essential execution codes. Pacemakers usually have less ROM than RAM. 

The wide range of electrophysiologic disorders treated with pacemakers and defibrillators requires devices with various capabilities and settings. Generic classification codes have been developed to... 

Bernstein, A. D., and Parsonnet, V., The NASPE/BPEG Pacemaker-Lead Code (NBL Code), Pacing Clin. Electrophysiol., 1996b 19(ll pt 1) 1535-1536. 

Specific frequency. The receiving coil is tuned to that frequency (called the carrier frequency). The carrier frequency is modulated to encode the information transmitted. There are two methods amplitude modulation (AM) and frequency modulation (FM). In pacemakers, the common method is to turn the radiofrequency carrier on and off very rapidly to represent a binary code so that a 1 or a 0 would be represented by pulses (short versus long) (Fig. 2.13). 

All pulse generators can be identified radiographically to some degree. Historically, the position of the cell or battery and the position of the radiopaque circuit components were unique to each model. However, as the shape of pulse generators has become less distinctive, identification of the manufacturer from these characteristics alone is not usually possible. Most pacemakers have an identification code visible on radiographic views of the generator. Once the radiographic code and manufacturer have been identified, the company can be contacted via a toll-free telephone number and the company s technical service staff should be able to assist in pacemaker identification. 

A permanent pacemaker s three-letter (or sometimes five-letter) code simply refers to how it s programmed. 

Remove items in room causing electromechanical interference (such as electric razors, radios, and cautery devices). Check ground wires on the bed and other equipment for damage. Unplug each piece and see if interference stops. When you locate the cause, ask a staff engineer to check it. If the pacemaker is still firing on the T wave, notify the doctor and turn off the pacemaker. Have atropine available in case HR drops. Call a code and institute CPR if needed. 

A code, usually three or four letters long, is commonly used to describe pacemaker mode or function. 

The capabilities of permanent pacemakers can be described by a five-letter coding system. Typically, only the first three letters are used. ... 

---