- Have anxiety, panic attacks, or are highly stressed
- Take certain medicines or stimulants
- Have certain medical conditions that aren't related to heart problems, such as an overactive thyroid
- Have certain heart problems, such as arrhythmias (irregular heartbeats), a previous heart attack, heart failure, heart valve problems, or heart muscle problems
This answer from the National Heart, Lung and Blood Institute has been reviewed and/or edited by Dr. William D. Knopf.