Difference between Atrial Fibrillation and Atrial Tachycardia

Atrial Fibrillation vs Atrial Tachycardia

What are atrial fibrillation and tachycardia?

The heart has two upper chambers called the right and left atrium. It has two lower chambers called the right and left ventricles. Electrical impulses are generated in the right atrium by a group of cells forming the Sino-atrial node (natural pacemaker of the heart) which travel to the Atrio-ventricular node and are then transmitted to the ventricles causing them to contract and pump the blood to the lungs and the body. Atrial fibrillation and atrial tachycardia are types of arrhythmias i.e. heart rhythm disorders which cause inadequate blood supply to the body. They occur when multiple signals are sent from the atrium to the ventricle.

Difference in conduction pattern

Atrial fibrillation is a condition which causes rapid heart rate and irregular heartbeat whereas Atrial tachycardia causes rapid heart rate while the heartbeat is regular. In atrial fibrillation, abnormal impulses are produced in the atrium and the atria beat irregularly. They contract partially and rapidly and are not able to pump adequate blood. In Atrial tachycardia, impulses are not generated from the Sino-atrial node but from multiple locations in the atria. In atrial fibrillation, the heart rate is more than 300 beats/minute whereas in atrial tachycardia, it ranges from 100-200 beats/minute.

Difference in causes

Atrial fibrillation is seen in cases of heart valve diseases (Mitral stenosis, Mitral regurgitation), congenital heart diseases, heart attacks (Ischemic heart disease), pericarditis (inflammation of the outer layer of the heart), high blood pressure (hypertension) etc. It is also seen in lung diseases like pneumonia and lung cancer. It may occur in hyperthyroidism and due to excessive intake of alcohol. Atrial tachycardia commonly develops after surgery for repair of congenital or valvular heart disease. It may be seen in Chronic obstructive pulmonary disease, bacterial pneumonia, diabetes and low potassium levels. It also occurs due to intake of coffee, alcohol and drugs like digoxin.

Difference in signs and symptoms

Patients with atrial fibrillation develop fluttering/thumping sensation in the chest, breathlessness on lying down and swelling of lower limbs. In both cases, patient develops palpitations, chest pain, dizziness, weakness, fainting episodes and light headedness due to inadequate blood flow.

Both conditions are identified clinically while examining the pulse rate. Tests like ECG, stress test, echocardiogram and 24 hours Holter monitoring will help the physician to diagnose the cause. Other tests like Complete blood count, Thyroid stimulating hormone levels, electrolyte levels, renal profile and chest X-ray may be done.

Difference in treatment

Treatment in both cases includes medicines to slow the heart rate like beta blockers, calcium channel blockers. Medicines like anti-arrhythmic drugs to bring the heart rhythm back to normal are used. Anticoagulants (drugs to prevent blood clot formation) like warfarin and heparin are used in cases of atrial fibrillation to prevent stroke. Reduced intake of coffee, tobacco and alcohol are essential

Summary-

Atrial fibrillation is a condition in which there is rapid and irregular heart rate whereas Atrial tachycardia consists of only a rapid heart rate. Atrial fibrillation is seen in high blood pressure, heart valve diseases, heart attacks, pneumonia, hyperthyroidism etc whereas atrial tachycardia is usually seen after surgeries done for correction of congenital heart disease and valvular heart disease. It is also seen in diabetes, bacterial pneumonia and low potassium levels.

Patient develops chest pain, breathlessness, palpitations, dizziness, fainting episodes etc. On examining the pulse of the patient, these conditions are identified. ECG, chest X-ray, blood tests will confirm the diagnosis.
Drugs to reduce the heart rate and bring back the heart rhythm to normal are used in both cases. Anti-coagulants are also used to prevent clot formation.

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