Sudden Loud And Fast Heartbeat

[Scarlett]

This evening when I've been lying down quietly I've noticed my heartbeat suddenly get very loud and fast for a few seconds, then it calms down again. This is not on exertion or any reason I can think of. It's done it about 6 times this evening. Should I be worried? No other symptoms.

[Buenchico]

Before providing you with a link, I'll give an important quote from it:
[i]"Most episodes of SVT are harmless, do not last long and settle on their own without treatment."[i] i.e. there's probably absolutely nothing to worry about.

However it would still be sensible to get yourself checked over by a GP:
http://www.nhs.uk/conditions/Supraventricular-tachycardia/Pages/Introduction.aspx

[Sqad]

What you are describing are palpitations and if they are not associated with any other symptoms such as shortness of breath or tightness in the chest then they are almost certainly harmless.
You have described an attack which one might describe as fleeting and should not cause concern.
It is difficult to say what the cause is, as the episode is so short loved, but anxiety is high on the list. In most cases no cause is ever identified?

[Eve]

I've found some medication can contribute too. I was getting a loud racing heartbeat even when not doing anything, seemed to have been caused by taking Day Nurse for a cold given they stuff they stick in it to keep you going, similarly some have caffeine etc... in them.