Tachycardia types seen on ECG

A. Atrioventricular nodal re-entry tachycardia (AVNRT). The pathogenic mechanism behind the arrhythmia is a re-entry circuit within the atrioventricular node. The QRS complex is narrow and the ventricular rate is regular 185/min. In typical AVNRT the impulse travels over the so-called slow pathway from the atrium to the ventricle and returns over the so-called fast pathway; this explains the re...