Tachycardia or Fast Heart Rate

What is Tachycardia?

The two main types of tachycardia are abnormal supraventricular tachycardias (which originate in the upper chambers of the heart, the atria) and ventricular tachycardias (which originate in the lower chambers of the heart, the ventricles).

The most common forms of tachycardias are:

• Paroxysmal supraventricular tachycardia- generally has a rate of 140 to 200 beats per minute, develops spontaneously, stops and starts suddenly, and may recur. Chronic tachycardia occurs when symptoms last until they're treated medically.
• Atrial flutter - the atria beat at 240 to 300 beats per minute, although the actual heart rate is much slower, because not all of these impulses are translated into contractions of the ventricles
• Ventricular tachycardia - a very serious arrhythmia initiated in the ventricles, in which the heart rate is usually between 150 and 250
• Atrial fibrillation

What are the symptoms of tachycardia?

The main symptom is a very fast heart rate. Other symptoms may include

• shortness of breath
• dizziness
• fainting
• chest pain
• severe anxiety

What causes tachycardia?

An increase in your heart rate is a normal response to physical exercise or emotional stress. Other things that can increase heart rate include substances such as caffeine or amphetamines. An overactive thyroid gland (hyperthyroidism) can also cause a fast heart beat. These forms of tachycardia are known as sinus tachycardia.

Tachycardia other than sinus tachycardia may be caused by an electrical disturbance within the heart (without an anatomic deformity), or by congenital defects, coronary artery disease, chronic disease of the heart valves, or chronic lung disease.

How is it treated?

Medical treatment depends on the cause and type of the tachycardia.

Sinus tachycardias usually do not require treatment other than addressing any underlying causes, for example you will probably want to avoid caffeine, smoking, and excessive alcohol.

A supraventricular paroxysmal tachycardia may respond to some simple maneuvers your doctor can explain to you. This may involve holding your breath for a minute, bearing down (as if straining with a bowel movement), splashing the face with cold water, or massaging the carotid artery in the neck. In other cases, drugs may be prescribed to slow the heartbeat on a continual basis.

Catheter radiofrequency ablation is a minimally-invasive procedure performed without opening the chest - instead by going in with a catheter through the blood vessels to reach the heart tissue. This method uses heat to destroy abnormal tissue that is causing the tachycardia. When successful, this procedure restores normal rhythm and eliminates the need for daily medications.

If tachycardia is severe, or arises from the ventricle, immediate injection of medication or electric shock may be required to stimulate the heart to return to a normal rate. In severe and persistant cases of ventricular tachycardias, a defibrillation device may be implanted surgically to help maintain a normal heart rhythm.

Ventricular fibrillation is when there is no effective heart beat, just useless quivering of the heart. This is a life threatening situation. Blood circulation is not achieved. Ventricular fibrillation requires continuous CPR until emergency medical attention arrives.

In elderly people or those with underlying heart disease, it'simportant to treat tachycardias quickly because a fast heart rate that goes on for a prolonged period of time may result in decreased heart function and complications.

The Mayo Clinic is a good source of further information about tachycardia.

Do you have an implanted defibrillator? Or are you taking meds to control tachycardia? Share your experiences with others.

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