My heart gets agitated for short periods of time
by cigarette smoke, or pollen, or allergens or vehicle exhaust.
If I consume too much potassium, sodium or calcium, or chocolate, or caffeine, or carbohydrates during the day, my heart beat will become erratic for long periods of time
, either too slow, or too fast, or too hard or too weak.
When my heart starts beating hard, it usually lasts for quite a while. I wish my heart would stop it's hard beating after just 10 beats.
I hope that you can find the cause of your heart beat irregularity and take corrective action.