If a clot breaks loose, it can block a brain artery, causing a stroke. If palpitations are due to a condition in which the upper chambers of the heart quiver instead of beating properly (atrial fibrillation), blood can pool and cause clots to form. Rarely, palpitations can be caused by life-threatening arrhythmias and can cause your heart to stop beating effectively. This might be more likely if you have a heart problem, such as congenital heart disease or certain valve problems. If your heart beats rapidly, your blood pressure can drop, causing you to faint. For palpitations caused by a heart condition, possible complications include: Unless a heart condition is causing your heart palpitations, there's little risk of complications. Have other heart problems, such as an arrhythmia, a heart defect, previous heart attack or previous heart surgery.Have an overactive thyroid gland (hyperthyroidism).Take medicines that contain stimulants, such as some cold or asthma medications.

Have an anxiety disorder or have regular panic attacks.You might be at risk of developing palpitations if you: Heart rhythm changes (arrhythmias) might cause a very fast heart rate (tachycardia), an unusually slow heart rate (bradycardia), a normal heart rate that varies from the usual heart rhythm or combination of the three. Occasionally heart palpitations can be a sign of a serious problem, such as an overactive thyroid gland (hyperthyroidism) or an abnormal heart rhythm (arrhythmia). Hormone changes associated with menstruation, pregnancy or menopause.Stimulants, including caffeine, nicotine, cocaine, amphetamines, and cold and cough medications that contain pseudoephedrine.Strong emotional responses, such as stress, anxiety or panic attacks.Often the cause of your heart palpitations can't be found. Request an Appointment at Mayo Clinic Causes

Heart beating fast for no reason