attack and is brought on by over stimulation of the parasympathetic nerve,
the vagus.
The parasympathetic nerves hold
the adrenalin-releasing nerves
in check.
In these attacks, they "check" too severely and the heart slows to an uncomfortable rate.
As she says, "Remember, the attack is also a result of too much nervous stimulation, your heart is not diseased, the attack does not harm your heart.