What are double potentials?
Answer:
The term double potential literally means two potentials or signals. Most referred to in the atrium, double potentials are atrial electrograms with two discrete deflections per beat separated by an isoelectric or low amplitude baseline. These may also be referred to as split signals.
Where might you find double potentials?
Answer:
This is often observed on lines of block both anatomical (normal existence) and those created with ablation.
The crista terminalis is a good example of an anatomical line of block that will display split potentials. The existence of these signals in areas of scar or ablation will be described in future posts.
What is the Crista?
Answer:
The crista terminalis is a smooth ridge of tissue from the roof of anterior/lateral right atrium from the SVC down to the IVC, dividing the smooth and trabeculated tissue. This area is one of the more common locations for atrial tachycardias. It is also a border or barrier for the typical atrial flutter circuit.
The two signals that you see when the catheter is positioned on the crista is local atrial depolarization on the opposite sides of the line of block as see in this illustration.
