electroanatomic mapping to determine scar regions in patients with atrial fibrillation

For patients who have prior catheter ablation, when they are in sinus rhythm, the voltage map can be used to identify low voltage areas using a threshold of 0.2 – 0.45 mV. However, such a voltage threshold for maps acquired during atrial fibrillation has not been well established. This is a method to maximize the topologically matched low voltage areas between the atrial fibrillation and sinus rhythm maps. 

successful catheter ablation

Radiofrequency (RF) catheter ablation in warm salt water. Temperature and impedance needed to be in a range for the RF generator to work. A set of working parameters are:
1. RF generator POWER set to 50 W, TEMPERATURE set to 43 degree Celsius, TIME set to 20 s.
2. Warm salt water temperature is about 50 degree Celsius, a lot of salt added so that the IMPEDANCE reading of the RF generator is about 65 Ohm.

Ablation experiment video:


The meat is beef. The white circular dots are lesion points. We can see that the cross-section of the lesion is very shallow. If we want a deeper lesion, need to increase ablation time. But the tissue temperature will rais quickly and exceed the temperature threshold that the RF generator will automatically cut of power.