Atrial Tachycardia

Atrial tachycardia is one type of supraventricular tachycardia. Normally, each heartbeat starts in the sinus node, the heart's natural pacemaker in the right atrium. In atrial tachycardia, another spot in the atria (the upper chambers of the heart) sends signals faster and takes over the rhythm. The heart rate is usually 100 to 250 beats per minute. These signals still pass to the ventricles through the normal pathway, so the heartbeat is usually regular and is felt as a rapid pounding.

Types of Atrial Tachycardia

A frequently seen type is focal atrial tachycardia, in which fast signals come from a single spot, for example near the openings of the pulmonary veins or around the tricuspid valve. Multifocal atrial tachycardia comes from several spots at once, so the rhythm is irregular; this type often accompanies severe lung disease in older adults. There is also atrial tachycardia caused by signals circling around scar tissue, usually after heart surgery or ablation for atrial fibrillation. This form is similar to the one covered on the Atrial Flutter page.

Coming and Going or Continuous

Some people have episodes that come and go. An episode often starts with a heartbeat that gradually speeds up, then slows down before it stops. In others, especially children and teenagers, atrial tachycardia can continue almost all day. Because it comes to feel normal over time, it sometimes goes unnoticed until tiredness, shortness of breath, or swelling appears. A fast heart rate that persists for weeks can weaken the heart muscle, a condition called tachycardia-induced cardiomyopathy. Pumping function usually recovers once the rhythm is controlled.

Triggers and Treatment

Atrial tachycardia can occur in a healthy heart, but it more often accompanies heart disease, lung disease, or previous heart surgery. Low potassium levels, an overactive thyroid, caffeine, alcohol, and some medicines can trigger it. Treatment starts by addressing the triggers, followed by medicines that control the heart rate. If episodes keep coming back or continue nonstop, catheter ablation can deactivate the trigger spot. In multifocal atrial tachycardia, the main treatment is improving the lung disease and oxygen levels. A general overview of fast heart rates is covered on the Tachycardia page.

Your doctor starts by asking about your symptoms, the medicines you take, and any history of heart or lung disease. An ECG taken during tachycardia shows a fast rhythm with P waves, the waves from the atria, that have a different shape from normal sinus rhythm. The shape of these waves gives a clue to the location of the trigger spot. If episodes come and go, a Holter monitor or long-term recorder helps capture an episode and measure how long the tachycardia lasts each day.

Echocardiography assesses the size of the atria, the valves, and pumping strength, especially if the tachycardia has been going on for a long time. Blood tests check potassium, magnesium, thyroid function, and, if needed, medicine levels. If ablation is being considered, an electrophysiology study maps the location of the trigger spot or circling signal pathway from inside the heart with the help of a three-dimensional map.

Atrial tachycardia often does not cause severe symptoms, but a fast heart rate that keeps coming back or does not go away still needs to be checked. Early evaluation helps find the trigger and prevent the heart muscle from weakening. Go to the emergency room right away if danger signs appear.

• A fast heartbeat that often comes back or lasts for hours
• A resting pulse that stays above 100 beats per minute without a clear cause
• Tiredness, shortness of breath, or leg swelling that becomes more noticeable
• A child who seems to tire easily and has a fast pulse
• Fainting, severe chest pain, or severe shortness of breath: go to the emergency room right away