Anxiety causing palpitations, or having a true heart problem?

Probably not: With anxiety your body and brain are in "high alert" and therefore a lot of adrenaline is being produced. Adrenaline is the ultimate heart stimulant so it may cause your heart to beat fast and your blood pressure to go up. If this "high alert" state is maintained for prolonged periods of time it may take a toll on the heart so you need to be evaluated to get your anxiety under control.

Hard to say: Anxiety can cause palpitations in someone who does not have a heart problem. However, abnormal fast heart rhythms can make you anxious. Wearing a heart monitor can help sort out if you have an abnormal heart rhythm.