What does the VDD pacing system specifically do?

The VDD pacing system is designed to provide dual-chamber pacing with a focus on the ventricles, while also sensing activity from the atrium. In this configuration:

• The 'V' in VDD represents ventricular pacing, meaning that the system actively paces the ventricles when needed, particularly in cases where the intrinsic pacing needs may not meet the physiological demands of the patient.

• The 'D' stands for dual sensing, indicating that the device can sense physiological events from both the atrium and the ventricle, allowing it to monitor the heart's natural rhythm effectively.

• The second 'D' emphasizes the device's ability to detect atrial activity, which is essential for coordinating the heartbeat and maintaining proper hemodynamic function.

This unique combination allows a VDD system to pace the ventricles while still being responsive to the atrial signals, ensuring a comprehensive approach to cardiac rhythm management. The system is particularly beneficial in patients with certain types of atrioventricular (AV) block, where both atrial sensing and ventricular pacing are crucial to maintaining an effective cardiac output.

In summary, the primary function of the VDD pacing system is to pace the ventricles effectively, while also allowing for the sensing of atrial activity, promoting