Spontaneous Atrioventricular Nodal Reentrant Tachycardia in Patients with Idiopathic Ventricular Arrhythmias: The Incidence, Clinical, and Electrophysiologic Characteristics

INTRODUCTION: Spontaneous or inducible atrioventricular nodal reentrant tachycardia (AVNRT) may coexist with idiopathic ventricular arrhythmias (IVAs). The aim of this study was to determine the incidence and the clinical and electrophysiologic characteristics of patients with spontaneous AVNRT among patients with IVAs. METHODS: Nine hundred eighty-seven consecutive patients with IVA (n = 398), patients with clinical and spontaneous AVNRT (n = 327), and patients with preexcitation syndrome (n = 262) were prospectively included in the study. RESULTS: Spontaneous AVNRT was present in 36 (9.0%) of 398 patients with IVA. The most common (97%) mode of presentation was palpitation due to spontaneous AVNRT. Absence of symptoms was frequent among patients with IVA and without spontaneous AVNRT compared to patients with IVA and spontaneous AVNRT (28.9% vs 0%, P = 0.0001). Patients with IVA and spontaneous AVNRT had lower median premature ventricular contraction (PVC) burden (1.9% vs 9.45%, P = 0.0001) and higher left ventricular ejection fraction (LVEF; 64.2 ± 4.9% vs 59.2 ± 9.9%, P = 0.0001) compared to patients with IVA and without spontaneous AVNRT. Relatively high PVC burden (≥10%) was present in 19.4% of patients with spontaneous AVNRT and IVA. The prevalence of IVA was significantly higher in patients with AVNRT compared to patients with preexcitation syndrome (11% vs 0.76%, P < 0.0001). CONCLUSIONS: Spontaneous AVNRT among patients with IVAs was relatively common in our study population. Spontaneous AVNRT in patients with IVAs can be a protective factor for left ventricular function. Greater LVEF in patients with spontaneous AVNRT and IVA compared to patients with IVA alone can be explained by earlier recognition of IVAs due to presence of symptomatic AVNRT and/or lower PVC burden.