What are Automatic Tachycardias?

An automatic tachycardia is a type of tachycardia (heart rate greater than 100 beats per minute) caused by the spontaneous generation of abnormal electrical impulses within the heart. Rarely, automatic tachycardia causes symptoms such as shortness of breath, dizziness, and fainting, but most people are not aware of the condition unless they undergo an echocardiogram in order to diagnosis another cardiac issue. Treatment for automatic tachycardia typically centers on dealing with the underlying cause, such as heart failure, anemia, or lung disease. Severe tachycardia, if not treated, can lead to sudden death.

Types of Automatic Tachycarcardias

Automatic tachycardias are individuated based on where abnormal electrical impulses arise from:

• Superventricular tachycardia, or automatic atrial tachycardia, occurs when the cells that are "automatically" firing are located within the atria.
• Ventricular, or automatic ventricular tachycardia, occurs when the abnormal electrical impulses come from the ventricles.
• Automatic junctional tachycardia occurs when abnormal impulses arise near the AV node, which is near the "junction" of the atria and the ventricles.
• Inappropriate sinus tachycardia, or IST, occurs when abnormal impulses originate in the sinus node.
• Atrial ectopic tachycardia occurs when the "irritable focus" or place at which electrical impulses emanate is in the atria of the heart.

Symptoms

Automatic tachycardias do not always cause discernible symptoms. However, some people with the condition may experience any of a number of symptoms, among them:

• Anxiety
• Fatigue
• Dizziness or lightheadedness
• Fainting (syncope) or near-fainting spells
• Heart palpitations or a feeling of fluttering in the chest
• Shortness of breath
• Pain or pressure in the chest

Causes

Automatic tachycardia occurs when cells in the heart produce electrical impulses more quickly than the sinus node does, thus taking over the rhythm of the heart and producing tachycardia. These arrhythmias are often seen in people who have an acute illness and are medically unstable and in the cardiac intensive care unit.

Among the conditions associated with automatic arrhythmias are:

• Acute lung disease (such as pulmonary embolus or pneumonia)
• Acute myocardial infarction (heart attack)
• Severe metabolic abnormalities such as low blood oxygen levels, low potassium or magnesium blood levels, or very high levels of adrenalin
• Anemia
• Increased thyroid activity
• Heart muscle damage from heart failure
• Severe bleeding

Diagnosis

Because they rarely cause discernible symptoms, automatic tachycardias typically are diagnosed during an electrocardiogram (EKG) that's being performed in relation to another suspected illness.

This non-invasive test involves attaching small metal sensors called electrodes to the chest and arms. The electrodes can pick up and measure electrical charges generated by the heart as it beats, which the equipment translates into a graph that visibly represents a person's heart rate and rhythm.

EKG wave patterns not only verify alterations in heart rhythm but also can provide information about which region in the heart is affected based on the shape of the waves on the graph.

Treatment

In acute cases, which account for most automatic tachycardia, treatment focuses on identifying and dealing with the underlying medical problem as quickly as possible. Once the condition is stabilized, the heart rhythm is likely to return to normal.

Persistent automatic atrial tachycardia usually is treated with ablation therapy, a procedure in which tiny scars are made in the heart tissue to correct arrhythmias.

A Word From Verywell

A diagnosis of any sort of heart problem is bound to cause concern—especially if it doesn't cause symptoms and appears to come out of the blue, as is often the case with an automatic tachycardia. Chances are, if you are found to have this condition, it will have been discovered while you were being tested for another health issue and so once that is addressed, your rapid heart rate will return to normal. Automatic tachycardia should be dealt with as soon as it's been detected, however, so it's important to always pay attention to any signs or symptoms that indicate you may have a health problem and to get regular physical examinations so that you are a step ahead of any potential disease or condition.