That would be an adrenaline rush, of which is an effect from a lot of games (very common on heart to beat retro games).
I'm fairly surprised that you get it in PvP games but not Dark Souls (although I have never played Dark Souls myself) but generally there will always be those sorts of moments in a particular setting in a particular genre/game, differing from person to person ofcourse.
Since it's different between person to person I would suggest that it is something that changes at the same time that your personality changes, so there is no particular way to change it other than self growth.
The only real thing that you can do when you get these adrenaline rushes is to stop and calm down, it will not do anything in the long term though.
You could perhaps search for methods that people use to deal with this, but I don't think that it would be of much help as it's just something that almost magically appears or disappears in the way you as a person function.
I wouldn't find it so strange that it occurs while you are playing card games and such, I think that even hits a stereotype on the head.
I'm not sure if there is any negative effects on health that this is happening, but i'm not sure that this is something that you would want to particularly change as it enhances pleasures.
You can either wait until you grow out of it and do what you can to tolerate/deal with it or you can figure out how to grow beyond it, which is not as clear as tips/instructions as you will have to explore yourself deeply.
Although, I would recommend that you just take advantage of it to enhance your video/card game playing pleasure.