reentry /rē·en″trē/ [L, re, again; Fr, entrée] , (in cardiology) the reactivation of myocardial tissue for the second or subsequent time by the same impulse. Reentry is one of the most common causes of arrhythmias. For example, paroxysmal supraventricular tachycardia may be caused by sinus nodal reentry, atrioventricular (AV) nodal reentry, or AV reentry by way of the AV node and an accessory pathway; atrial flutter is caused by an atrial macroreentry circuit. Reentry also underlies some forms of ventricular tachycardia and extrasystoles. AV and AV nodal reentry mechanisms may be terminated by a vagal maneuver, adenosine, or procainamide.
