User:Mr. Ibrahem/Atrioventricular reentrant tachycardia

Atrioventricular reentrant tachycardia (AVRT), is a type of abnormal fast heart rhythm. Symptoms may include episodes of palpitations, lightheadedness, and chest discomfort. Onset is generally sudden with a heart rate of 150 to 250 beats per minute. Complications are rare. It is a type of paroxysmal supraventricular tachycardia (PSVT).

Causes include Wolff–Parkinson–White syndrome (WPW). The underlying mechanism involves an accessory pathway which allows electrical signals to travel between the upper and lower chambers of the heart, outside the AV node. There are two types: orthodromic in which the signal travels through the accessory pathway from the ventricle to the atria and the QRS complex is generally narrow; and antidromic in which the signal travels from the atria to the ventricle and the QRS complex is wide. Permanent junctional reentrant tachycardia (PJRT) is a type of orthodromic AVRT.

Initial treatment, in those who are otherwise stable, is often with vagal maneuvers. If this is not effective adenosine may be used. Other measures may include verapamil, procainamide, or beta blockers. If this is not effective or the person is unstable electrical cardioversion may be carried out. Recurrent attacks may be prevented with radiofrequency ablation. In those who cannot have ablation flecainide may be used.

AVRT is uncommon, affecting less than 1 % of people. While about 0.2% of people have WPW on their ECG, not all develop a fast heart rate such as AVRT. It is the second most common type of PSVT after AV nodal reentrant tachycardia (AVNRT). Onset is often around the age of 9 to 37. While an accessory pathway was first described in 1893 by Stanley Kent, symptomatic cases were not described until 1930 by Louis Wolff, John Parkinson, and Paul Dudley White.