Paradoxical Aging Changes of the Atrioventricular Nodal Properties in Patients With Atrioventricular Nodal Re-Entrant Tachycardia

Abstract

Background: This study aimed to investigate the impact of aging on electrophysiological characteristics in patients with atrioventricular nodal re-entrant tachycardia (AVNRT). Methods and Results:The 2,111 patients who underwent an electrophysiological study and radiofrequency (RF) catheter ablation of AVNRT were enrolled. The patients were divided into 4 groups according to age (group 1: <20 years; group 2: 20-39 years; group 3: 40-59 years; and group 4: ≥60 years). The gender distribution differed with age. The atrio-Hisian interval, and effective refractory periods (ERP) of the right atrium, ventricle, antegrade slow pathway, retrograde slow pathway and fast pathway, and tachycardia cycle length all increased with age. However, a paradoxical change in the fast pathway ERP was noted. The fast pathway ERP was significantly longer in group 2 than in other groups, and was associated with the largest tachycardia window. The response to catecholamines was similar between different age groups. Procedure time, radiation time, and complications did not differ. However, the number of RF impulses was higher in group 2 compared with other groups (7.6±9.3, P=0.04), which might imply a differing complexity during the ablation. Conclusions:Paradoxical aging changes of AVN electrophysiological characteristics were associated with a different atrioventricular nodal conduction property and the number of RF impulses. (Circ J 2011; 75: 1581 -1584

What Can We Tell by the Fast Pathway Effective Refractory Period?

“…8 Most of their observations are comparable to those reported in earlier studies. 9, 10 Although there are variable differences in each parameter to some extent, this may be partly explained by the different basic cycle lengths used to determine the refractory periods.…”

“…In the study by Tseng et al, 8 the anterior slow pathway ERP of the 20-49-year-olds was longer than that of subjects aged between 40 and 50 years by only a few milliseconds. In contrast, the antegrade fast pathway ERP was longer than that of that of the 40-50-year-olds by more than 10 ms on average.…”

“…8 The number of subjects analyzed in the study was large enough to minimize contingent overestimation or underestimation of the variables. The longer anterior fast pathway ERP resulted in widening of the tachycardia window and a higher tendency of AVNRT attacks.…”

Clinical and Electrophysiological Characteristics of Typical Atrioventricular Nodal Reentrant Tachycardia in the Elderly – Changing of Slow Pathway Location With Aging –

“…30 We found here that there were longer AH intervals and cycle length durations during tachycardia in elderly patients. In contrast, TCL was longer in elderly patients in the present study but the VA interval did not differ during tachycardia, so this might suggest that there was a prolonged antegrade slow pathway conduction time during AVNRT and that it was mainly responsible for the higher TCL in these patients.…”

“…29 It was indicated in the literature that TCL tends to be higher in elderly patients with AVNRT. 24,25,29, 30 Additionally, the AH interval and effective refractory periods of antegrade slow unpaired t-test, respectively. A P-value <0.05 was regarded as statistically significant.…”