What does the third letter of NGB code indicate?

The third letter of the NGB code indicates the pacemaker's response to the sensing. In pacing terminology, this response explains how the pacemaker manages its pacing activities based on the detection of intrinsic cardiac activity. Specifically, this letter indicates whether the pacemaker will inhibit (turn off pacing) or trigger (turn on pacing) based on what it senses from the heart's natural electrical signals.

For instance, if the device senses intrinsic activity, it may decide not to pace, thereby allowing the heart to function on its own. Conversely, if it does not sense activity during a designated time, it may respond by initiating pacing to ensure continued heart rhythm. Understanding this part of the NGB code is crucial for healthcare providers to determine how a pacemaker will interact with the patient's own cardiac physiology.