Electrocardiographic and electrophysiologic characteristics of anterior, midseptal and right anterior free wall accessory pathways

Abstract

Anteroseptal, midseptal and right anterior free wall pathways may be distinguished by using programmed stimulation of the summit of the right ventricular septum and especially with changes in the VA interval with development of right bundle branch block during orthodromic AV reentrant tachycardia.

Paraseptal accessory connections in the proximity of the atrioventricular node and the His bundle. Additional observations in relation to the ablation technique in a high risk area

“…Approaching paraseptal pathways through the superior vena cava has been previously proposed [12]. In our experience, all successfully ablated paraseptal pathways were approached through the femoral vein.…”

“…In contrast to ACs of the left ventricular free wall or the posteroseptal space, the proposed algorithms have a lower predictive value for correctly identifying the site of the paraseptal pathway. An overlap between their ECG appearance has been found in anteroseptal and midseptal pathways with even those localized in the right ventricular free wall [12]. Furthermore, the terminology referring to paraseptal pathways is somewhat confusing.…”

“…It is remarkable that these pathways are frequently destroyed with minimal RF energy and not uncommonly their activity is temporarily interrupted during catheter manipulation because of their superficial subendocardial course [9]. In contrast, the bundle of His is a structure more deeply situated, surrounded by the central fibrous body, thus requiring higher RF energy power settings for ablation [12]. Such observations most likely explain the unexpectedly low incidence of complete AV block induction despite the high ablation success rate for septal pathways in most published series.…”

Coronary Sinus Activation Pattern in Patients with Atrioventricular Nodal Reentrant Tachycardia

“…Standard criteria 4,[8][9][10] were used to exclude the presence of a septal accessory pathway or atrial tachycardia. Specifically, single ventricular premature depolarization either failed to advance the atrial electrogram or advanced the atrial electrogram and reset the tachycardia, while a ventricular extrastimulus delivered when the His bundle was refractory never advanced the next atrial deflection.…”

“…Standard pacing techniques 8,9) were used to evaluate the anterograde and retrograde AV node properties and the induction of tachycardia. Isoproterenol (1 to 3 mg/min) was used to facilitate the induction of AVNRT if baseline pacing failed to induce the tachycardia.…”