here are some questions you should answer..is it for the first time you have experienced this? was there any triggering factor present or anything you can recall or associate with this? if you are on any kind of medication?your weight? your blood pressure?do you smoke? how much is your caffeine(tea,coffee or sodas) intake? i assume this was your first time, so no need to worry at all as this is quite common. if this was not ur first time,recall every event and notice if any triggering factor was present like anxiety, any food stuff, medication(most commonly allergy medication), etc and try to avoid it. last possibility is a condition known as "transient tachycardia". but again this is not a diagnosis when u have a single episode. it can lead to a great anxiety in the patients with this condition and must consult a doctor for proper checkup. the best home remedy for prevention of these episodes is regular brisk walking or light weight exercises or yoga. eat healthy food,avoid oily stuff.check your blood pressure regularly..