Analysis of clinical and electrophysiological characteristics of children with Wolff-Parkinson-White syndrome or ventricular pre-excitation / 中华实用儿科临床杂志

Objective@#To summarize the clinical and electrophysiological characteristics of children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.@*Methods@#One hundred and seventy-nine consecutive children with Wolff-Parkinson-White syndrome or ventricular pre-excitation who were hospitalized at Beijing Anzhen Hospital Affiliated to Capital Medical University and planned to accept radiofrequency ablations were selected.Electrocardiogram and echocardiography were completed and detailed clinical data were collected before ablations.Anterograde refractory period of accessory pathways (ERPAPA) and retrograde ventriculoatrial conduction were measured during electrophysiology studies.The clinical and electrophysiological characteristics of these children were analyzed.@*Results@#The ratio of left-sided to right-sided accessory pathways was 1.001.93(61 cases vs.118 cases). Six out of 61 patients with left-sided accessory pathways were verified by electrophysiology study.There was no statistical difference of P-R interval and QRS duration between patients with right-sided and left-sided accessory pathways(all P>0.05). Twelve patients were combined with congenital heart diseases.Fourteen patients with right-sided accessory pathways were of ventricular pre-excitation induced dilated cardiomyopathy.ERPAPA was measured successfully in 110 patients, ERPAPA less than 250 ms accounted for 32.7%(36/110 cases). Six children with two pathways were recognized.Antidromic atrioventricular reentrant tachycardia was induced in 3 children.One child had slow conduction pathway localized in right-sided septum.@*Conclusions@#Right-sided overt accessory pathways are more common in children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.Organic heart diseases are not uncommon.Besides congenital heart disease, a small proportion of patients with right overt accessory pathways may develop ventricular pre-excitatory induced dilated cardiomyopathy resulting from ventricular wall dyskinesia.Most of the decremental retrograde ventriculoatrial conduction is the characteristic of ventricular muscles rather than the accessory pathways in nature.Two pathways are not uncommon in children with Wolff-Parkinson-White syndrome or ventricular pre-excitation.Before finishing radiofrequency ablation, the anterograde and retrograde function of the accessory pathway should be evaluated in detail again because it is easy to neglect the existence of another accessory pathway.

Interrelated Atrioventricular Reentrant Tachycardia and Idiopathic Left Ventricular Tachycardia in a Patient with Manifested Bystander Accessory Pathway

Double tachycardia is defined as the coexistence of supraventricular tachycardia (SVT) and ventricular tachycardia (VT). In clinical practice, incidentally encountered double tachycardia is difficult to diagnose during electrophysiology study without prior documentation of both tachycardias. SVT can be confused with VT because SVT sometimes show an aberrant conduction depending on heart rate. In the present case, a patient with Wolff-Parkinson-White syndrome exhibited atrioventricular reentrant tachycardia (AVRT) via a concealed bypass tract and idiopathic left ventricular tachycardia (ILVT), which were difficult to discriminate because of their similar cycle length and interrelationship.

The Incidence of Dual Atrioventricular Nodal Pathways and the Differences of Their Electrophysiologic Properties According to the Inducibility of Atrioventricular Nodal Reentrant Tachycardia / 대한내과학회지

OBJECTIVES: Refractory period and conduction time of the slow and fast pathways in the atrioven-tricular node are known to be the most important determinant of the inducibility of atrioventricular nodal reentrant tachycardia (AUNRT) but their relationship has not been determined in Korean. METHODS: Two hundred and ten patients under-gone electrophysioiogic study. One hundred twenty two patients with dual AV nodal pathways were divided into two groups (group I, 77 patients with no inducible AVNRT; group II, 45 patients with inducible AVNRT). RESULTS: Antegrade dual AV nodal pathways were documented in 77 patients (47%) out of 165 patients on whom AVNRT was not induced, Antegrade ERP of slow pathway in paced rhythm (600 msec) was shorter in group II than in group I (331 +/- 14 msec vs 269 +/- 47 msec, p<0.05). Ventriculoatrial block cycle length (VABCL) and retrograde ERP of the AV conduction system were significantly shorter in group 2 than in group 1 (p<0.001). Maximum slow pathway conduction times in sinus rhythm and paced rhythm (600msec) in group 2 were significantly longer than in group 1 (sinus rhythm: 332 +/- 68msec vs. 379 +/- 88msec, p<0.005; paced rhythm: 332 +/- 69msec vs. 392 +/- 85msec, p<0.005). The ERP gaps of two AV nodal pathways of group 2 in sinus rhythm and in paced rhythm were also significantly longer than those of group 1 (sinus rhythm 41 +/- 3msec vs. 78 +/- 50msec, p<0.001; paced rhythm 36 +/- 32 msec vs. 72 +/- 19msec, p<0.005). The incidence of intact ventriculoatrial conduction was significantly higher in group 2 than in group 1 (p<0.05). Antegrade slow pathway conduction time (A2H2 interval) at the time of AVNRT induction with single atrial premature depolarization (APD) with a coupling interval over 10 msec less than that of an APD producing AH jump were not correlated with VABCL (r=0.193, p<0.05). CONCLUSION: Dual AV nodal pathways were observed in 47% of patients with no-inducible AVNRT group. The inducibility of AVNRT appears to be closely ralated to the some conduction characteristics of the dual pathways and the refractoriness, i.e. maximum slow pathway conduction time, the ERP gap of two pathways, retrograde fast pathway ERP, VABCL.

Radiofrequency Catheter Ablation for the Treatment of Atrioventricular Reentrant Tachycardia

BACKGROUND: Atrioventricular reentry is the most common cause of supraventricular tachycardia in Korea. Radiofrequency catheter ablation(RFCA) is now accepted to be the safe and effective treatment modality for the elimination ofr accessory pathway conduction in patient with atrioventricualr reentrant tachycardia(AVRT). METHODS: To evaluate the clinical usefulness of RFCA for the treatment of AVRT, this study was conducted in 109 patients(male 68, female 41) with atrioventricular accessory pathway and documented AVRT after electrophysiologic study. RESULTS: A total of 112 accessory pathways were identified in 109 patients. The mean power outputs of the successful ablations at the atrial side of the annulus were higher than those at the ventricular side(34.0+/-8.9W versus 20.0+/-7.6W, p<0.01), but the maximum temperatures were lower at the atrial side of the annulus than those at the ventricular side (66.4+/-14.0degrees C versus 77.2+/-6.4degrees C, p<0.01). Accessory pathway conduction was eliminated in 102 of 112 pathways successfully(success rate 91v). There were 4 nonfatal complications(3.7%). 3 patients with hemopericardium and 1 with femoral artery thrombus, during or after ablation porcedures. Recurrences of AV reentrant tachycardia or delta wave on the electrocardiogram occured in 5 patients, and 4 of them had successful second procedures. There were no late complications during a mean follow-up period of 13+/-5 months. CONCLUSION: RFCA is highly effective and safe treatment modality in ablation accessory pathway conduction.