Visualize the infinity symbol (the figure eight on its side) midway down your back and behind the liver. This represents where the parasympathetic and sympathetic system interact. Think of one loop as the parasympathetic system (involuntary systems like breathing and blinking). Think of the other loop as the sympathetic system (muscle actions that take a thought).
What happens in panic attacks, is that these two systems get tangled and confused. You suddenly have to think about breathing, thoughts race, the body reacts in different ways. So as a visualization, simply focus on this infinity symbol and make it have perfect symmetry in your mind. At first one loop of the infinity symbol may be bigger or tangled or even broken and the other one could be perfectly fine. Just simply tweak the loops with your mind so that they are equal and balanced.
When you use this technique, it takes all the focus off of all the subtle aspects of the body that are reacting and puts the focus on fixing it at the site.