Mechanisms of atrioventricular junctional tachycardia: Role of reentry and concealed accessory bypass tracts

摘要: Electrophysiologic investigations with programmed stimulation of the human heart have clearly established participation atrioventricular (A–V) junction in three different types junctional reciprocating tachycardia: (1) paroxysmal supraventricular tachycardia Wolff-Parkinson-White syndrome; (2) vast proportion “paroxysmal atrial tachycardia” without evidence preexcitation during sinus rhythm antegrade conduction; and (3) permanent or almost (chronic relapsing) form its characteristic rate-dependent initiating mechanism. The obvious presence syndrome does not necessarily imply that accessory pathway will be utilized tachycardia. Conversely, absence preexcitation, mechanism A–V has been traditionally attributed to pure intranodal dissociation, often definite direct proof. Concealed pathways (with unidirectional block) may more frequent than realized should carefully searched for. Proof utilizes an for retrograde conduction atrium requires meticulous electrophysiologic studies. Conclusions based on various findings misleading. Emphasis must placed positive diagnostic features. One following observations prove disprove a Kent bundle induction block tachycardia; influence electrically induced ventricular premature beats upon patterns activation (4) functional branch rate Analysis events at onset rather is probably less important but also provide suggestive clues about reentry. Observation variables helpful: behavior relation ventriculoatrial (V–A) prolongation H–V interval (5) sites. Precise understanding pathophysiology because specific therapy (pharmacologic, pacemaker surgical) ultimately depend accurate knowledge underlying mechanisms.