ECG Tutorial

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AV Nodal Re-entrant Tachycardia


The combination of an unfortunately timed atrial ectopic and the existence of two strands of conducting tissue with opposite electrical properties in the junctional region of the heart can establish a rapidly discharging, self sustaining, re-entrant loop of depolarising current. This current will be discharged distally into the ventricles and also in a retrograde fashion into the atria. This is the mechanism underlying a common paroxysmal supraventricular tachycardia (SVT); AVNRT. We will explain the mechanism underlying AVNRT in this video. Understanding the underlying mechanism generating this tachycardia will help you identify this common arrhythmia on the ECG.