AV nodal reentrant tachycardia is a medical condition characterized by a rapid heart rate caused by the abnormal electrical activity in the heart's AV node. There are several synonyms for this condition, including AVNRT, atrioventricular nodal reentrant tachycardia, and paroxysmal supraventricular tachycardia. All these terms refer to the same condition where the heart beats faster than normal due to the reentrant circuit between the AV node and the atria. While AVNRT is not typically life-threatening, it can cause discomfort, palpitations, and shortness of breath, making it essential to seek medical attention if you experience such symptoms.