Mitral valve prolapse (MVP) is a condition in which the heart's mitral valve doesn't function properly, causing a usually sporadic and benign heart murmur. Medical types have long suggested a link between the condition and panic disorder. Which makes sense to me, since MVP-caused palpitations may well have triggered my first-ever panic attack.
But a new meta-study (i.e. a study of other studies) calls the connection between MVP and panic into question:
Published results are insufficient to definitely establish or to exclude an association between MVP and panic disorder. If any relationship does actually exist, it could be said to be infrequent and mainly occur in subjects with minor variants of MVP.
At this point, 20 years later, I'm much less concerned with what caused my panic attacks, because I realize that question is a distraction from what should be my focus vis-a-vis panic: namely, how to accept and cope with its presence in my life. Does mitral valve prolapse cause panic? Or, rather, do panic attacks cause mitral valve prolapse? Those are chicken-and-egg-type questions: unanswerable and ultimately meaningless.
The article does include a paragraph that is closer to what I believe in my gut is the actual relationship between MVP and panic: MVP causes heart palpitations. When it does so in a person biologically predisposed for panic disorder, that person will be more likely to consider his palpitations to be mortally dangerous:
An alternative to a direct causal relation could be that MVP contributes other factors to the triggering of panic crises in individuals with greater biological vulnerability. A cognitive model suggests that patients with panic disorder tend to interpret different stimuli or bodily sensations in a catastrophic manner.81 These stimuli may include, for example, a cardiologic diagnosis communicated to the patient in an abrupt manner or the perception of a tachycardia with no major clinical significance, situations that can be encountered among patients with MVP. These stimuli may be interpreted as a risk to life and may lead to more anxiety, with autonomic symptoms triggering panic crises in predisposed persons.46
So panic isn't caused by MVP. Rather, the stress resulting from misinterpreting MVP as a threat to life can trigger panic, in much the same way as other stressors (losing a job, a relationship break-up, financial troubles, health troubles, violent accidents...) can trigger panic. Bad wiring in that thumping, pulsing thing in your chest, in other words, can be seen as akin to the roadside improvised explosive device that sends the soldier home from Iraq with nascent post-traumatic stress disorder.