Initiation of atrioventricular nodal reentrant tachycardia in patients with discontinuous anterograde atrioventricular nodal conduction curves with and without documented supraventricular tachycardia: observations on the role of a discontinuous retrograde conduction curve

Classification and differential diagnosis of atrioventricular nodal re-entrant tachycardia

Recent evidence on atrioventricular nodal re-entrant tachycardia has identified several types of this common arrhythmia, with potential therapeutic implications. This article reviews the relevant new information, discusses the differential diagnosis of atrioventricular nodal re-entrant tachycardia, and summarizes the electrophysiological criteria for classification of the various forms of the arrhythmia.

Effects of isoproterenol in facilitating induction of slow-fast atrioventricular nodal reentrant tachycardia

This study demonstrates that patients with poorer conduction properties of the anterograde slow and retrograde fast pathways usually need isoproterenol to facilitate induction of atrioventricular nodal reentrant tachycardia. Isoproterenol infusion usually facilitates induction of tachycardia by enhancing the retrograde ventriculoatrial conduction.

Longitudinal clinical and electrophysiological assessment of patients with symptomatic Wolff-Parkinson-White syndrome and atrioventricular node reentrant tachycardia

BACKGROUND

Functional changes of the accessory AV pathways and dual AV node pathways are very important for patients with Wolff-Parkinson-White syndrome or AV node reentrant tachycardia who refuse to receive long-term medication or radiofrequency catheter ablation. However, no studies of serial clinical and electrophysiological characteristics in these patients have been performed.

METHODS AND RESULTS

One hundred thirteen patients with Wolff-Parkinson-White syndrome or AV node reentrant tachycardia were included in this study. The first and second follow-up electrophysiological studies were performed in years 5 and 10 after the baseline study, respectively. Conduction properties of the accessory pathways became poor over time. After a mean follow-up period of 9 +/- 1 years, antegrade ventricular preexcitation and retrograde accessory pathway conduction disappeared in 22.5% and 7.8% (P < .01), respectively; dual AV node pathway physiology persisted and retrograde fast pathway disappeared in 10.8% of the patients. Baseline conduction properties of the antegrade and retrograde accessory pathways and the retrograde fast pathway independently predicted late loss of conduction. Spontaneous disappearance of the original tachyarrhythmias occurred in 10.3% of all patients, and newly developed tachyarrhythmias in 15.2%. The incidence (38.5%) of newly developed atrial fibrillation was significantly higher in patients with manifest accessory pathways. Furthermore, symptom scores and attack frequency increased significantly over time in the patients with accessory pathways and AV node reentrant tachycardia.

CONCLUSIONS

Disappearance of the original tachycardia and changing patterns of tachycardia, also with an increase in symptom scores and attack frequency, suggested that a detailed evaluation of these events is important and early intervention with radiofrequency ablation would be helpful.

Initial onset of accessory pathway-mediated and atrioventricular node reentrant tachycardia after age 65: clinical features, electrophysiologic characteristics, and possible facilitating factors

OBJECTIVE

To evaluate the clinical features electrophysiologic characteristics, and possible facilitating factors in older patients (> or = 65 years) with initial onset of accessory pathway-mediated and atrioventricular (AV) node reentrant tachycardia.

DESIGN

Of the patients undergoing electrophysiologic study and radiofrequency catheter ablation of accessory pathway-mediated and AV node reentrant tachycardia at this institution, patients with initial tachyarrhythmia after age 65 years were compared with those presenting initially before age 30.

SETTING

A tertiary medical center for the general public.

PARTICIPANTS

Sixty-six patients had their initial symptoms after age 65: Group I, 32 patients with accessory pathway-mediated tachycardia, and Group II, 34 patients with AV node reentrant tachycardia. Four-hundred forty patients had their initial symptoms before age 30: Group III, 283 with accessory pathway mediated tachyarrhythmia, and Group IV, 157 with AV node reentrant tachycardia.

INTERVENTION

All patients underwent electrophysiological study to determine the mechanisms of tachyarrhythmia, and radiofrequency catheter ablation for treatment of tachycardia.

RESULTS

(1) Older patients with initial arrhythmia had incidence of critical clinical manifestations, including tachyarrhythmia-related syncope and cardioversion, similar to those with initial arrhythmia at a younger age. (2) Patients in Group III, showed anterograde effective refractory period (ERP) of the AV node (P = .432), longer anterograde ERP of the accessory pathway (P = .004), and greater difference of the anterograde ERP between the AV node and the accessory pathway (D-ERP) (P = .003) similar to patients in group I. In Group II, the ERP and Wenckebach cycle length of the retrograde fast pathway was significantly longer than in Group IV (P = .037 and P < .001, respectively), and a greater percentage of patients in Group II than in Group IV AV node reentrant tachycardia needed isoproteronol to facilitate the induction of reentrant tachycardia (P = .034). (3) Patients in Group I and Group II had a higher incidence of supraventricular and ventricular ectopic activity than those in Group III (P = .002 and P = .005, respectively) and Group IV (P = .024 and P = .012, respectively) in 24-hour ambulatory electrocardiograms.

CONCLUSION

The initial onset of accessory pathway-mediated tachycardia after age 65 may be caused by changes of electrophysiologic properties (greater D-ERP) as well as increased supraventricular and ventricular ectopic activity. Influence of the autonomic nervous system, rather than changes of conduction properties in the AV node, and increase in ectopic activity may contribute to the new onset of AV node reentrant tachycardia in older adults. The choice of antiarrhythmic drugs and radiofrequency ablation require attention to the clinical profile and facilitating factors of reentrant tachycardia in this group of patients.

Retrograde dual atrioventricular nodal pathway in patients with atrioventricular reciprocating tachycardia using concealed accessory pathways

We present electrophysiological studies in two patients with atrioventricular reciprocating tachycardias. The first patient had anterograde dual atrioventricular nodal pathways with a right-sided concealed accessory pathway. The retrograde atrioventricular nodal pathway showed evidence suggestive of slow pathway properties. After block was induced with ajmaline in the accessory pathway, a typical pattern of discontinuous retrograde atrioventricular nodal conduction curves was recognized. We then observed three types of induced atrioventricular reentry. The other patient had continuous anterograde atrioventricular nodal conduction, a fast-conducting retrograde atrioventricular nodal pathway and a left-sided concealed accessory pathway. After refractoriness had been induced in the accessory pathway with ajmaline, a typical pattern of retrograde dual atrioventricular nodal pathways was recognized, and it proved impossible to induce atrioventricular nodal echoes. Induction of block or impairment of conduction with ajmaline in the concealed accessory pathway proved helpful in the disclosure of retrograde dual atrioventricular nodal pathways by means of the ventricular extrastimulus method.