‘feeling defeat of vein - above all within décolletage, chief, and arms’?
Answers: The combination of feeling the sensation of blood pulsing through your vein and low blood pressure is probably due to arterial dilation. You have some major arteries surrounded by these regions, which would make sense. You're probably fine. Try noting exactly what you're doing since and during these episodes, and what you did to make them stop--even if you think it in recent times miraculously stops on its own.
It could also be psychologic.
If you're seriously worried about it, go see a doctor and make available him/her the notes you've jotted down.
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