To what extent are anxiety attacks and panic attacks caused by deep subconscious emotional triggers?

This is a very high percentage and again is in the 90% range. Even when people have a conscious perception of situations, circumstances, and beliefs about themselves and their plight in the world that make them prone to having misgivings and feelings of anxiety, there will always be a deeper level present within the deep subconscious sensitizing them to those very points of vulnerability, and then it is the straw that breaks the camel’s back, so to speak, of the current life circumstances that seem to be the entire explanation and the true culprit. But the true culprit is really the deep karmic history that is much more powerful and often a confluence of multiple circumstances from multiple parallel lives, all of which is rumbling in the deep subconscious, and then a triggering event in the current life can send the person into a symptomatic episode with a worsening of chronic anxiety, or the generation of a true panic attack that can be incapacitating depending on the vulnerabilities of the person and their history with such problems developing to become a recurring phenomenon.