What would cause your pulse to remain over 100bpm at rest with no history of heart disease?

Many Factors: Hi nikki, tachycardia or an elevated heart rate can be caused by multiple different factors including thyroid problems, anxiety/stress, and heart disease even without a history of heart disease. If your heart rate remains elevated for several minutes, it is vital that you visit an emergency department quickly.

Fast heart rate.: Please check that you are not running a fever or getting dehydrated. Also depends on your age and your general medical condition. Would be a good idea to get checked for anemia, thyroid problems & other infections. Your doctor would do an ekg and holter monitor if this has been going on for a while depending on a detailed history.

Many things: Dehydration, excessive thyroid hormone, anemia...

Long list: Dehydration, caffeine, anxiety, anemia, high thyroid hormone levels are a few. Meds like albuterol can also. Amphetamines can cause tachycardia for over a day. It sounds like you might be most concerned with arrythmias like atrial fibrillation, flutter or others. Your physician will evaluate possible causes and treat or refer you to a specialist.