Atrioventricular nodal reentrant tachycardia initiated by catecholamine-induced ventricular tachycardia. A case report

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.

Atrioventricular nodal reentrant tachycardia associated with idiopathic ventricular tachycardia: clinical and electrophysiologic characteristics

BACKGROUND

Case reports have described the coexistence of ventricular tachycardia (VT) and supraventricular tachycardia in the same patient. This study examines the frequency of dual atrioventricular nodal (AVN) physiology, AVN echo beats, and atrioventricular nodal reentrant tachycardia (AVNRT) in patients with VT.

METHODS

Programmed atrial and ventricular stimulation was performed in 132 consecutive patients referred for electrophysiologic study of symptomatic VT. Of the 132, 99 patients had structural heart disease, and 33 patients had idiopathic ventricular tachycardia (IVT).

RESULTS

Among the 33 patients with IVT, 23 had dual AVN physiology. Compared with patients with structural heart disease undergoing VT ablation, dual AVN pathways (70% vs 27%, P < .0001), dual AVN pathways with echo beats (24% vs 8%, P = 0.03), and AVNRT (21% vs 1%, P = .0002) were more common in patients with IVT.

CONCLUSION

Dual AVN physiology and AVNRT appear to be associated with IVT. This finding suggests that patients with IVT should undergo a complete electrophysiologic evaluation, and the diagnosis of coexistent AVNRT should be considered in this population.

Frequency of spontaneous and inducible atrioventricular nodal reentry tachycardia in patients with idiopathic outflow tract ventricular arrhythmias

OBJECTIVES

We sought to assess the frequency of spontaneous or inducible atrioventricular nodal reentry tachycardia (AVNRT) in patients referred for radiofrequency ablation (RFA) of idiopathic outflow tract ventricular arrhythmias.

BACKGROUND

In patients with no obvious heart disease, AVNRT and outflow tract ventricular tachycardia (VT) are the most frequently encountered supraventricular and ventricular tachycardias, respectively. An increased coexistence of the two arrhythmias has been recently suggested.

METHODS

In 68 consecutive patients referred for RFA of an idiopathic ventricular outflow tract arrhythmia, a stimulation protocol including repeated bursts of rapid atrial pacing, up to triple atrial extrastimuli during sinus rhythm and rapid ventricular pacing was performed before and after isoproterenol infusion following RFA of the ventricular arrhythmia. In patients with inducible AVNRT, RFA of the slow pathway was performed.

RESULTS

Of the 68 study patients, 17 (25%) had either spontaneous AVNRT documented prior to RFA of the ventricular arrhythmia (n = 4) or inducible AVNRT at the time of RFA of the ventricular arrhythmia (n = 13). AVNRT was induced by atrial pacing in 15 (88%) of 17 patients: in 3 patients without isoproterenol and in 12 patients during isoproterenol infusion. Uncomplicated RFA of the slow pathway was successfully achieved in all patients with inducible AVNRT.

CONCLUSION

Spontaneous or inducible AVNRT is relatively common in patients with idiopathic outflow tract ventricular arrhythmias. Atrial stimulation, especially when performed after isoproterenol infusion plays a major role in AVNRT inducibility. Although we performed RFA of the slow pathway in patients with inducible AVNRT and no prior tachycardia documentation, the question whether this is mandatory remains unsettled.