1/22. AV reentrant and idiopathic ventricular double tachycardias: complicated interactions between two tachycardias.An electrophysiological study was performed in a 61 year old man with Wolff- Parkinson-White (WPW) syndrome. At baseline, neither ventricular nor supraventricular tachycardias could be induced. During isoprenaline infusion, ventricular tachycardia originating from the right ventricular outflow tract (RVOT) with a cycle length of 280 ms was induced and subsequently atrioventricular reentrant tachycardia (AVRT) with a cycle length of 300 ms using an accessory pathway in the left free wall appeared. During these tachycardias, AVRT was entrained by ventricular tachycardia. The earliest ventricular activation site during the ventricular tachycardia was determined to be the RVOT site and a radiofrequency current at 30 W successfully ablated the ventricular tachycardia at this site. The left free wall accessory pathway was also successfully ablated during right ventricular pacing. The coexistence of WPW syndrome and cathecolamine sensitive ventricular tachycardia originating from the RVOT has rarely been reported. Furthermore, the tachycardias were triggered by previous tachycardias.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
2/22. A wide "gap" in retrograde conduction through a concealed accessory atrioventricular pathway depending on ventricular pacing sites.We present a 57-year-old man with wolff-parkinson-white syndrome who exhibited a wide "gap" in retrograde conduction through a concealed atrioventricular accessory pathway. The appearance of the wide "gap" depended on the ventricular pacing sites. While ventricular extrastimuli at a basic cycle length of 600 msec from the right ventricular outflow tract consistently conducted to the atria, retrogradely through the accessory pathway, those from the right ventricular apex repeatedly revealed disappearance of the retrograde conduction at the wide coupling intervals from 550 to 380 msec. The mechanisms of this rare "gap"-like phenomenon are discussed in this paper.- - - - - - - - - - ranking = 0.5keywords = cycle (Clic here for more details about this article) |
3/22. Demonstration of phase-3 and phase-4 retrograde block in a second concealed accessory pathway after an initial successful radiofrequency ablation of a 'normal' concealed accessory pathway.We report a patient with concealed wolff-parkinson-white syndrome who, following catheter ablation, demonstrated phase-3 and phase-4 retrograde block in a concealed accessory pathway. After an initial 'apparently successful' ablation, retrograde conduction was through the atrioventricular node during constant ventricular pacing. Ventricular extrastimulus testing was performed at a basic drive cycle length of 600 ms. Unexpectedly, ventricular extrastimuli at coupling intervals of 440-380 ms were conducted retrogradely over an accessory pathway, consistent with a phase-3 and phase-4 retrograde block in the accessory pathway. Residual accessory pathway conduction was eliminated in a single ablation session.- - - - - - - - - - ranking = 0.5keywords = cycle (Clic here for more details about this article) |
4/22. Transient appearance of antegrade conduction via an AV accessory pathway caused by atrial fibrillation in a patient with intermittent wolff-parkinson-white syndrome.A 55 year old man with intermittent Wolff-Parkinson-White (WPW) syndrome had an episode of atrial fibrillation (AF) that lasted for 117 days. After interruption of the AF a Delta wave appeared that lasted for two days and then disappeared. exercise stress and isoprenaline infusion could not reproduce the Delta wave, but after another episode of AF which lasted for seven days a persistent Delta wave appeared that lasted for six hours. In an electrophysiological study performed on a day without a Delta wave, neither antegrade nor retrograde conduction via an accessory pathway was seen, but after atrial burst pacing (at 250 ms cycle length) for 10 minutes, a Delta wave appeared lasting for 16 seconds. Atrial electrical remodelling-that is, the shortening of the atrial effective refractory period caused by AF, is a possible mechanism of the appearance of the Delta wave.- - - - - - - - - - ranking = 0.5keywords = cycle (Clic here for more details about this article) |
5/22. A case of concealed WPW syndrome with three different reciprocal tachycardias due to triple AV nodal pathways.Triple atrioventricular nodal pathways (TAVNP) occur occasionally, but it is rare for them to produce more than two different tachycardias. Here we report a case of concealed WPW syndrome with three different tachycardias. During electrophysiologic studies, three different reciprocal tachycardias were induced. tachycardia #1 was characterized by a cycle length of 230 msec and an A'-H interval of 70 msec. For tachycardia #2, these parameters were 300 msec and 140 msec, while they were 370 msec and 200 msec for tachycardia #3. During all three tachycardias, the earliest atrial activity was observed in the left atrium. Ventriculoatrial conduction occurred following ventricular stimulation, and the earliest atrial activity was observed in the left atrium, indicating the existence of left-sided accessory pathway. Persistence of tachycardia for 15-30 min caused marked pulmonary congestion. The heart rate was very high (260 beats/min) during tachycardia #1, and the pulmonary arterial pressure rose to 40/30 mmHg, with the pulmonary arterial diastolic pressure remaining at about 30 mmHg throughout the tachycardia. It seems that the pulmonary venous pressure rises abnormally during paroxysmal supraventricular tachycardia with a very high heart rate and that pulmonary congestion can easily occur during a short period of tachycardia.- - - - - - - - - - ranking = 0.5keywords = cycle (Clic here for more details about this article) |
6/22. His bundle recordings in a case of complete atrioventricular block combined with pre-excitation syndrome.In a patient with complete A-V block suffering from attacks of dizziness an intermittent A-V conduction with a short P-R interval and a delta wave of the conducted ventricular complex were observed. After accelerating the sinus rate by atropine and by exercise, one-to-one conduction was established with QRS complexes of WPW type A configuration. His bundle recordings revealed a complete block within the normal conduction system at the level of the A-V node. A slow junctional rhythm with a normal H-V interval was activating the ventricle. During atrial pacing a one-to-one conduction through an accessory pathway could be documented at cycle lengths between 800 and 380 msec. sandwiched in between zones of complete block at smaller or longer cycle lengths. During ventricular stimulation no retrograde V-A conduction could be observed. The findings support the thesis of at least two functionally different A-V pathways in patients with pre-excitation syndrome.- - - - - - - - - - ranking = 1keywords = cycle (Clic here for more details about this article) |
7/22. Opposite effects of propafenone and flecainide in a patient with reciprocating supraventricular tachycardia.A 46 year-old woman with wolff-parkinson-white syndrome (postero-septal accessory pathway), symptomatic for recurrent episodes of nonsustained paroxismal supraventricular tachycardia (PSVT), was empirically treated with propafenone (600 mg/day). After a week of therapy the patient returned to the hospital after an episode of syncope. She referred a significant increase in duration and frequency of "palpitations". Under treatment with propafenone a sustained PSVT could be induced during transesophageal testing. During the electrophysiologic study performed off drugs, only a nonsustained PSVT could be induced. After flecainide infusion (1 mg/kg) anterograde block of the accessory pathway was observed and only few beats (less than 8) of PSVT could be induced. The patient was discharged on flecainide (200 mg/day) and 1 month later a transesophageal testing was repeated showing an anterograde block of the accessory pathway at a pacing cycle length of 500 ms; no arrhythmias were induced. The patient has been asymptomatic on chronic oral therapy with flecainide during a follow-up period of 8 months. This case shows that 2 1c class antiarrhythmic drugs may have opposite effects (proarrhythmic and antiarrhythmic). Failure, or even the proarrhythmic effect of one drug, does not necessarily exclude the efficacy of another drug of the same subclass in preventing recurrence of PSVT.- - - - - - - - - - ranking = 0.5keywords = cycle (Clic here for more details about this article) |
8/22. Atrioventricular nodal reentry in the wolff-parkinson-white syndrome.Although supraventricular tachycardia in the Wolff-Parkinson-White (WPW) syndrome is generally due to atrioventricular reentry, the presence of the accessory pathway does not preclude other mechanisms of tachycardia. We observed AV nodal reentry in three of 95 consecutive patients (3.1%) referred for assessment of arrhythmias associated with WPW syndrome. The unique observation of spontaneous transition from atrioventricular reentry to AV nodal reentry at a similar cycle length was observed in one patient and is the subject of this report.- - - - - - - - - - ranking = 0.5keywords = cycle (Clic here for more details about this article) |
9/22. 'Incessant' tachycardias in wolff-parkinson-white syndrome. I: Initiation without antecedent extrasystoles or PR lengthening, with reference to reciprocation after shortening of cycle length.In 6 patients with the Wolff-Parkinson-White (WPW) syndrome, repetitive, almost continuous (incessant) reciprocating atrioventricular (AV) tachycardia has been shown to arise when the sinus cycle length was shortened to a critical point, at which unidirectional block occurred without the classical feature of PR prolongation. Though this phenomenon superficially resembles an aspect of chronic intranodal reciprocating tachycardia of children, basic differences can be identified. It was encountered more frequently in younger subjects; the only patient over 45 developed the arrhythmia as a complication of therapy. This incessant mechanism may explain some cases in which antiarrhythmic treatment does not control reciprocating tachycardia in the WPW syndrome, but such a mechanism can also occur spontaneously.- - - - - - - - - - ranking = 2.5keywords = cycle (Clic here for more details about this article) |
10/22. Bystander accessory pathway during AV node re-entrant tachycardia.Between 1970 and July 1980, wide QRS tachycardia due to re-entry confined to the AV node with bystander involvement of an accessory atrioventricular pathway (AAV) was documented in three of 290 patients with the wolff-parkinson-white syndrome studied at Duke Medical Center. In each of the patients, at least one transition between wide and narrow QRS morphology was recorded without change in either the cycle length of tachycardia or the atrial activation sequence. Two of the three patients had a single left-sided AAV (lateral, postero-lateral) showing antegrade conduction only. The third patient had two right-sided AAVs (free wall, septal), each capable of bidirectional conduction. Initiation and termination of repetitive concealed conduction into the ventricular insert of an AAV appeared to be one mechanism determining bystander AAV participation. documentation of the retrograde sequence of atrial activation during tachycardia, and examination of the effects of interpolated premature depolarizations from both the ventricle and mid-line atrium are the most helpful features in resolving the differential diagnosis of wide QRS tachycardia in patients with W-P-W syndrome.- - - - - - - - - - ranking = 0.5keywords = cycle (Clic here for more details about this article) |
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