Definition Sinus tachycardia is a heart rate greater than 100 beats per minute. The electrical impulses that cause the heart to beat come from the normal "pacemaker" of the heart.
What is going on in the body? This condition is a fast heartbeat that is not a true or primary arrhythmia, which is an abnormal heartbeat. Instead, it is a normal response to demands on the heart. The heart beats regularly in this condition, but faster than normal. This condition generally starts and stops gradually, such as at the beginning and end of exercise.
What are the signs and symptoms of the disease? Though symptoms often do not occur, signs and symptoms of this condition may include:
racing heart rate or pulse
a feeling of the heart pounding in the chest
dizziness in some cases
Other symptoms are generally related to the underlying cause of this condition.
What are the causes and risks of the disease? There are many possible causes of this condition, including:
What can be done to prevent the condition? This condition can be prevented only if the underlying cause can be prevented. For example, avoiding exercise or dehydration can prevent some cases. It is important to remember that this condition is not necessarily bad and is a normal response to certain situations.
How is the condition diagnosed? Affected people or a doctor can check their pulse and notice that it is greater than 100. An electrocardiogram (ECG) will show a pattern of normal heartbeats that are faster than 100 beats per minute.
What are the long-term effects of the disease? This condition itself usually has no long-term effects. In some settings, a fast heartbeat may cause chest pain or a heart attack. Some people get chest pain every time they exert themselves and the heart starts to beat faster. This is known as angina. This usually only occurs when someone has clogged arteries in his or her heart.
What are the risks to others? This condition is not contagious and poses no risk to others.
What are the treatments for the disease? Treatment may be directed at the underlying cause of this condition. For example, people may need:
fluids if they are dehydrated
paracetamol for a fever
antibiotics for an infection
extra oxygen if they have low oxygen
blood transfusions or iron pills for low blood counts
medications to treat a high thyroid hormone level
In the case of exercise sand some other causes, treatment is not needed. In fact, exercise that raises the heart rate above normal is advised for all people at least three times a week.
What are the side effects of the treatments? This depends on the treatments used. All medications have possible side effects. These may include allergic reactions, stomach upset, and other side effects. Specific side effects depend on the drugs used. Blood transfusions may cause allergic reactions or infections.
What happens after treatment for the disease? If needed, the heart rate can be monitored until it returns to normal. Once the underlying cause of this condition is treated, people are free to return to normal activities.
How is the disease monitored? A doctor should investigate unexplained, repeated, and frequent episodes of fast heartbeats. In many cases, monitoring is only done for the underlying condition, not the fast heart rate itself.
Author: Susan Woods, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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