Pacemaker Codes and Functions

Understanding Pacemaker Code Structure

• The American College of Cardiology recommends a standardized pacemaker nomenclature where each position has specific meaning, with the second letter representing the chamber(s) sensed 1
• The American College of Cardiology defines the pacemaker code structure as follows:

Clinical Application Examples

• The American College of Cardiology explains that VVI Mode paces the ventricle, senses the ventricle, and is inhibited by sensed ventricular activity, which is critical for understanding pacemaker function in patients with certain heart conditions 1, 3
• The American College of Cardiology describes DDD Mode as pacing dual chambers (atrium and ventricle), sensing dual chambers, and having a dual response (inhibits pacing when intrinsic activity is sensed, triggers ventricular pacing after sensed atrial activity) 1, 4
• The American College of Cardiology notes that VDD Mode paces only the ventricle, but senses dual chambers (both atrium and ventricle), allowing it to track atrial activity and maintain AV synchrony without atrial pacing capability 1, 2