Your idea about parasympathetic withdrawal is interesting and I’d never considered that. Still, unless I’m mistaken (always a good bet), I thought that in the absence of parasympathetic tone the heart rate levels out around 100, i.e. anything over 100 bpm implies the presence of sympathetic stimulation. So, if the heart rate in panic attacks goes over 100, it implies some degree of sympathetic effect (assuming their are no primary tachyarrhythmias at play*).
*Indeed, IIRC, some people are occasionally diagnosed as having panic attacks when the underlying issue is an SVT.
Because when I looked this is what I found. Only tiny increases in NE and no significant increases in epi during acute spontaneous episodes. Admittedly old but I don’t think it has been contradicted.
Of course increased sensitivity to sympathetic-parasympathetic balances, both centrally and peripherally may be part of the mix.
There are a lot of articles on how to differentiate panic attack from cardiac events but not as many on what causes chest pain in panic attacks. After a bit of searching I found this article: Panic Disorder and Chest Pain: Mechanisms, Morbidity, and Management. It lists potential causes including spasm of intercostal chest wall muscles, esophageal spasm, and coronary artery spasm. Apparently hyperventilation can cause coronary artery spam in addition to the all the other stuff discussed above. So some proportion of individuals have chest pain during panic attacks because they are effectively having an episode of Prinzmetal’s angina. Which I expect feels just like a heart attack.
I also found this article which looks at myocardial ischemia in panic attack specifically in patients with no underlying heart disease. Unfortunately to get the full article you either have to pay for it or have access to an academic library. But the discussion includes this interesting statement: “The only one who presented myocardial perfusion defect did not report any respiratory distress, forcing us to seek a further understanding to the results that do not pass through mechanisms involving hyperventilation.” So one of the study subjects did have myocardial ischemic during the induced panic attack but he didn’t hyperventilate so we have no idea why it happened.
And apparently individuals subject to panic attacks are also overall at greater risk of cardiovascular disease and mortality (including after controlling for confounders like smoking status). That “sense of doom” occasionally experienced in each being tied to decreased (or blocked) parasympathetic levels (and probably some GABA overlap) is I think a bit key. I don’t know of that occurring as part of adrenergic surges - it’s “fight or flight” not “sense of impending doom.”
To bring the non-medical more in on this conversation - the sympathetic system and the parasympathetic system push-pull in opposite directions. Sympathetic increase (and conversely parasympathetic decrease) is the classic adrenaline or epinepherine fight or flight reaction; parasympathetic increase (and conversely sympathetic decrease) lowers heart rate, blood pressure, and increases blood flow to the gut. The parasympathetic side is often referred to as a vagal response after a major nerve of the parasympathetic system and the impact of carotid artery massage, straining like have a bowel movement (Valsalva), and cold water in the face, mentioned by carryon occur due to that vagal stimulation. Substances that block the vagal response are called anticholinergics.
It seems we are not the first to consider this parasympathetic side of these things. Higher baseline parasympathetic tone is one way in which aerobic exercise may lower risk of cardiovascular death (and travels with lower heart rate and higher resting heart rate variability. (And decreased parasympathetic tone thus with higher mortality rates.) Those with anxiety disorder seem to have lower baseline parasympathetic (vagal) tone.
DSeid, I would like your opinion on something I posted earlier more than 30 years ago in my late 20’s and early 30’s I experienced the classic heart attack symptoms. Pain radiating from my left jaw down my left arm and feeling of pressure in the chest. The jaw pain and arm pain were fairly intense. Several years of Dr’s got no explanation. I traced it back to gulping air and solved the problem by wiping my mouth instead of swallowing.
I learned to test my saliva and if it was foamy I would simply start wiping my mouth and I always got quick relief. Never bothered again once I discovered this. I think the foamy saliva was caused by anxiety but not sure.
Can’t say I have too much insight to offer. Sorry. Glad you figured out something that helped though. Obviously they had crossed heart stuff off the list early and they must have thought about GERD …
Anyone else with more insight or better thoughts than I have?