Background and purpose: Drug responses vary markedly from patient to patient in atrioventricular nodal reentrant tachycardia (AVNRT), the most common form of paroxysmal regular supraventricular tachycardia in adults. However, clinical and electrophysiological (EP) characteristics of patients with AVNRT whose tachycardia attacks could not be adequately controlled by antiarrhythmic agents have not been studied in a large patient cohort. We aimed to define the clinical and EP features of patients with drug-refractory AVNRT.
Methods and results: A total of 266 consecutive patients with AVNRT undergoing catheter ablation after a period of medical treatment were analyzed: 144 patients with drug-refractory AVNRT (Group 1) and 122 patients with drug-responsive AVNRT (Group 2). Age was significantly higher (p=0.027) and the presence of hypertension (p=0.030), diabetes mellitus (p=0.047), and valvular heart diseases (p=0.008) was more frequent in Group 1 compared to Group 2. Among the EP features, atrial-His jump (81% vs 69%, p=0.028) and atrial vulnerability (26% vs 14%, p=0.018) were significantly higher, echo zone was significantly more long-lasting (44 ± 24 ms vs 38 ± 22 ms, p=0.018), and tachycardia cycle length (TCL) was significantly longer (348 ± 41 ms vs 329 ± 38 ms, p=0.000) in Group 1 than in Group 2. Multivariate analysis showed that hypertension (p=0.036), valvular heart disease (p=0.014), atrial vulnerability (p=0.037), TCL (p=0.003), and wide echo zone (p=0.028) were independent predictors for drug-refractory AVNRT.
Conclusion: In the presence of hypertension, valvular heart disease, atrial vulnerability, long-lasting echo zone, and relatively slow AVNRT, medical treatment is less likely to prevent the tachycardia episodes.
Keywords: Antiarrhythmic agents; Atrioventricular nodal reentrant tachycardia; Catheter ablation; Slow tachycardia.
Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.