How can I tell if I have or what kind of heart arrhythmia I might have?

It must be recorded. Precise diagnosis of a suspected arrhythmia requires a recording at the time of symptoms. Sometimes the problem is frequent enough to be demonstrated on a routine electrocardiogram (ecg). More often the symptoms are intermittent. There are several types of monitors that patients may wear or carry with them to obtain this recording when they feel symptoms.
EKG . If you feel palpitations or irregular heartbeats go to your doctor and get an ekg done, in majority of time it would show if there is a problem, however sometimes you might need a 24 hr or an event heart monitor to catch an episode of arrhythmia and to be diagnosed.