A DDDR pacemaker, also sometimes referred to as a DDDRO pacemaker, is a type of heart regulatory device that can be implanted in a person’s chest to monitor and regulate heartbeat. It is capable of pacing and sensing cardiac depolarization, which is a way of measuring the heart's electrical signal output and strength, in both chambers of the heart. It equipped with the ability to trigger as well as inhibit pacing, and can adjust the pacing rate automatically. However it is not usually capable of multisite pacing, which is essentially simultaneous regulation in both the right and left sides of either the atrium or ventricle. The atrium and ventricle are where blood is pulled in and pushed out of the heart.
Pacemakers are typically available in a variety of styles and with slightly different functionalities. One with a “DDDR” specification is generally implanted in both chambers of the heart, and can coordinate function between atria and ventricles. Devices in this category tend to be among the most advanced and complicated available, and are often able to set a more accurate, dependable rhythm than those that are focused on only one chamber or that are sensor-based and take their cues off of a person’s physical activity.
Understanding the Acronym
The North American Society of Pacing and Electrophysiology and the British Pacing and Electrophysiology Group categorize pacemakers according to what is known as the Generic Code (NBG Code). This code is where the letters “DDDR” come from.
The first and second letters represent the chambers of the heart in which pacing will occur and the chambers in which the pacemaker can detect cardiac depolarization as it happens, respectively. These two letters can either be “A” for atrium, “V” for ventricle, or “D,” meaning that the pacemaker is capable of dually pacing and sensing cardiac depolarization in both the atrium and the ventricle. As such, a DDDR pacemaker is one that focuses on both chambers at once.
The third “D” indicates that this sort of pacemaker can both trigger and inhibit pacing as needed. Devices that can only trigger pacing usually have a “T” here, while those that just inhibit it are usually named with an “I.” The “R” represents the ability of the pacemaker to involuntarily adjust the pacing rate with a rate modulator. If no such modulator were present, the name would usually have an “O” in the fourth position.
Possible Fifth Letter
Sometimes this type of pacemaker is labeled with the acronym “DDDRO,” where the final “O” represents the absence of multisite pacing — which is to say, this sort of pacemaker can’t usually set the rhythm in the right ventricle as well as in the left or in the right atrium as well as in the left or any combination of the atrium and ventricles. Most experts who simply see “DDDR” will know to imply the final “O.” If a pacemaker has this sort of dual pacing ability, it is almost always clearly indicated, often with a final “A,” “V,” or “D” — letters that typically correspond to where that additional pacing happens.
How the Device is Made
Like most pacemakers, those in the DDDR family are small devices made of a powerful battery, a sensor, and at least two insulated wires, sometimes called “leads,” that carry electrical signals from the device directly into the heart and from the heart back to the device. The precise technology that goes into making these tools changes somewhat regularly, but generally speaking the main goal is to monitor the strength and frequency of heartbeats, then trigger changes as needed for a person to maintain optimal cardiovascular health. A DDDR device is specially designed to regulate both chambers simultaneously, which means that it must be situated somewhat centrally so that a lead can enter each chamber relatively easily. Depending on the patient the leads may be of different lengths.
Who Might Need One
DDDR pacemakers are a good choice for people with a history of heart disease or people with abnormal heartbeats, or “arrhythmias.” These devices’ ability to monitor and control both chambers simultaneously can be a good way for doctors and other healthcare providers to take a comprehensive approach to pacing and rhythm. The DDDR’s dual approach most closely resembles what the heart would do on its own if it was healthier or stronger.
Implantation Basics
Installing this sort of device is usually pretty straightforward. Surgery is almost always required since it is an internal mechanism, but most of the time it is implanted just below the skin. Surgeons use sensors to place the wires into the heart’s chambers, which means that the heart itself doesn’t have to be exposed or open. Most practitioners consider implantation somewhat routine, and it usually only takes a few hours. Patients will often need to have their devices monitored periodically to be sure they are still doing their job properly. Additional surgeries may be required as needed to replace the battery or other moving parts, though this sort of maintenance isn’t usually needed but once every five or ten years.
