Filter by keywords:



Filtering documents. Please wait...

1/81. Intermittent bundle branch blocks in a patient with uncommon-type atrioventricular nodal reentrant tachycardia and enhanced atrioventricular nodal conduction.

    We report on a patient with uncommon-type atrioventricular (AV) nodal reentrant tachycardia with a short tachycardia cycle length (235-270 ms), in whom transient wide QRS tachycardia with both left bundle branch block and right bundle branch block aberrancy were followed by narrow QRS complexes. In addition, His-ventricular (H-V) block and a sudden prolongation of the H-V interval occurred during the tachycardia. As the determinant of these unusual findings, the possibility that the anterograde limb of the reentry circuit has an enhanced AV nodal conduction property is discussed, as is the clinical significance of this type of tachycardia.
- - - - - - - - - -
ranking = 1
keywords = block
(Clic here for more details about this article)

2/81. atrioventricular block occurring several months after radiofrequency ablation for the treatment of atrioventricular nodal re-entrant tachycardia.

    Atrioventricular (AV) block following radiofrequency (RF) ablation for the treatment of AV nodal re-entrant tachycardia (AVNRT) is a rare but well recognised complication of the procedure--the reported incidence ranges from 1% to 21%. Almost all cases of AV block occur during or shortly after the procedure, are transient, and recover quickly. Two patients (a 22 year man and a 72 year old woman) with symptomatic AV block occurring several months after slow pathway RF ablation, requiring permanent pacemaker implantation, are described. Both patients had had several 24 hour Holter recordings before the procedure, and in neither case was there any evidence of intermittent or persistent AV block. This is a rare complication with no definitive predictors; however, all efforts should be made to exclude AV block in patients presenting with suggestive symptoms following RF ablation. With the wide use of RF ablation for the treatment of AVNRT, more cases are likely to occur. A registry should allow documentation of the incidence of this complication.
- - - - - - - - - -
ranking = 1.2857142857143
keywords = block
(Clic here for more details about this article)

3/81. Radiofrequency catheter ablation of coexistent atrioventricular reciprocating tachycardia and left ventricular tachycardia originating in the left anterior fascicle.

    Coexistence of supraventricular tachycardia and ventricular tachycardia is rare. A patient with no structural heart disease and wide QRS complex tachycardia with a right bundle block configuration and right-axis deviation underwent electrophysiological examination. A concealed left atrioventricular pathway (AP) was found, and atrioventricular reciprocating tachycardia (AVRT) and left ventricular tachycardia (VT) originating in or close to the anterior fascicle of the left ventricle were both induced. Radiofrequency (RF) catheter ablation of the concealed left AP was successfully performed. Ten months later, VT recurred and was successfully ablated using a local Purkinje potential as a guide. Coexistent AVRT and idiopathic VT originating from within or near the left anterior fascicle were successfully ablated.
- - - - - - - - - -
ranking = 0.14285714285714
keywords = block
(Clic here for more details about this article)

4/81. Unusual induction of slow-fast atrioventricular nodal reentrant tachycardia. Report of two cases.

    INTRODUCTION: Generally, the induction of typical atrioventricular nodal reentrant tachycardia (AVNRT) occurs with a premature atrial stimulus that blocks in the fast pathway and proceeds down the slow pathway slowly enough to allow the refractory fast pathway time to recover. We describe two cases in which a typical AVNRT was induced in an unusual fashion. RESULTS: The first case is a 41-year-old man with paroxysmal supraventricular tachycardia. During the electrophysiology study, the atrial extrastimulus inducing the typical AVNRT was conducted simultaneously over the fast (AH) and the slow pathway (AH'). A successful ablation of the slow pathway was performed. During the follow-up no recurrence was noted. The second case is a 52-year-old woman with a wolff-parkinson-white syndrome due to a left posterior accessory pathway. After 5 minutes of atrioventricular reentrant tachycardia (AVRT) induced by a ventricular extrastimulus, a variability of the antegrade conduction was noted in presence of the same VA conduction. In fact, a short AH interval (fast pathway) alternated with a more prolonged AH intervals (slow pathway) that progressively lengthened until a typical AVNRT was induced. The ablation of the accessory pathway eliminated both tachycardias. DISCUSSION: A rare manifestation of dual atrioventricular nodal pathways is a double ventricular response to an atrial impulse that may cause a tachycardia with an atrioventricular conduction of 1:2. In our first case, an atrial extrastimulus was simultaneously conducted over the fast and the slow pathway inducing an AVNRT. This nodal reentry implies two different mechanisms: 1) a retrograde block on the slow pathway impeding the activation of the slow pathway from the impulse coming down the fast pathway, and 2) a critical slowing of conduction in the slow pathway to allow the recovery of excitability of the fast pathway. Interestingly, in the second case, during an AVRT the atrial impulse suddenly proceeded alternately over the fast and the slow pathway. The progressive slowing of conduction over the slow pathway until a certain point which allows the recovery of excitability of the fast pathway determines the AVNRT. This is a case of "tachycardia-induced tachycardia" as confirmed by the fact that the ablation of the accessory pathway eliminated both tachycardias.
- - - - - - - - - -
ranking = 0.28571428571429
keywords = block
(Clic here for more details about this article)

5/81. Case report: anterograde 2:1 and retrograde 3:2 Wenckebach block during atrioventricular nodal tachycardia: controversies of the upper and lower common pathways.

    The exact nature of the reentry circuit for the atrioventricular nodal reentrant tachycardia (AVNRT) and particularly the concept and role of the upper and lower common pathways is not well defined. Although it is well accepted that the His-Purkinje system and the ventricles are not an essential part of the tachycardia circuit, controversy still exists as to whether the atria are essential components of the circuit. We describe a patient in whom the AVNRT perpetuated despite the spontaneous development of 2:1 anterograde and 3:2 retrograde block. To our knowledge, such a combination of electrophysiological phenomenon has not been previously reported. The electrophysiological basis of these observations and their clinical implications are discussed.
- - - - - - - - - -
ranking = 0.71428571428571
keywords = block
(Clic here for more details about this article)

6/81. Late occurrence of heart block after radiofrequency catheter ablation of the septal region: clinical follow-up and outcome.

    INTRODUCTION: There are few data regarding the occurrence of delayed heart block at least 24 hours after radiofrequency catheter ablation (RFCA) of AV nodal reentry or posteroseptal accessory pathways (APs). We investigated the late occurrence of heart block in this population, the clinical outcome, and whether findings at electrophysiologic study could have predicted its development. methods AND RESULTS: Two of 418 patients with AV nodal reentry undergoing RFCA using a posterior approach and 1 of 54 patients with RFCA of a posteroseptal AP developed late heart block. Anterograde and retrograde AV nodal conduction before and after RFCA were normal. patients received 12, 15, and 32 RFCA lesions, respectively, using a mean maximum power of 44 W. The RFCA sites were the posterior septum for posteroseptal AP and the posterior and mid-septum for patients with AV nodal reentry, with no His electrogram ever recorded at the ablation site. During RFCA, junctional tachycardia occurred with 1:1 VA conduction in the patient with a posteroseptal AP, but occasional intermittent single retrograde blocked complexes were present in both patients with AV nodal reentry. No rapid junctional tachycardia or >1 consecutive retrograde blocked complex was ever observed during RFCA. Persistent high-degree AV block with junctional escape developed 2 days after RFCA in the posteroseptal AP patient. A permanent pacemaker was implanted, and normal conduction was noted 16 days after RFCA. Both patients with AV nodal reentry complained of fatigue, mainly on exertion, 3 to 4 days after RFCA, and ECG-documented exercise-induced variable AV block was obtained. Because heart block resolved in our initial patient, a prolonged monitoring period was allowed. Symptoms disappeared at 13 and 8 days, and a follow-up treadmill test showed normal PR interval and no heart block. No recurrence of heart block has been seen in any of these three patients. CONCLUSION: Late unexpected heart block after RFCA of AV nodal reentry and posteroseptal AP is rare, often resolves uneventfully in 1 to 2 weeks, and no specific electrophysiologic findings predicted its occurrence. Prolonged clinical observation is preferable to immediate pacemaker implantation in such patients.
- - - - - - - - - -
ranking = 2.1428571428571
keywords = block
(Clic here for more details about this article)

7/81. Facilitation of atrioventricular reentrant tachycardia by iatrogenic right bundle branch block.

    The present case report describes the diagnosis of a concealed bypass tract in the right lateral wall revealed by electrophysiologic evaluation performed in a patient with rare palpitations. A iatrogenic right bundle branch block (RBBB) caused the occurrence of an incessant atrioventricular reentrant tachycardia. The disappearance of the RBBB determined a very difficult induction of the tachycardia that, when induced, showed a shorter cycle length and ventriculoatrial interval than those observed during RBBB tachycardia. The presence of a RBBB ipsilateral to the right free wall accessory pathway provided a critical delay within the circuit thus allowing the bypass tract to recover excitability. This relevant delay also allows the sinus beat to initiate and stabilize the tachycardia thus rendering it incessant.
- - - - - - - - - -
ranking = 0.71428571428571
keywords = block
(Clic here for more details about this article)

8/81. Ablation of nonparoxysmal A-V nodal tachycardia.

    The present study describes the successful radiofrequency ablation of an uncommon type of A-V nodal tachycardia. Electroanatomical mapping of the right atria was used to locate the region of the earliest atrial activation and allowed for positioning of the ablation catheter and a successful 25-watt radiofrequency burn in this area terminating the tachycardia. The ability to visualize multiple projections of pertinent intracardiac structures allows a more rapid and systematic approach by marking all ablation points even in the presence of AV block or AV dissociation. Consequently, repeated burns can be eliminated in previously treated areas by electroanatomical mapping of the earliest depolarization and leading pacemaker.
- - - - - - - - - -
ranking = 0.14285714285714
keywords = block
(Clic here for more details about this article)

9/81. Radiofrequency catheter ablation for intra-atrial reentrant tachycardia after surgery of atrial septal defect: use of isopotential mapping (QMS system) to demonstrate bidirectional complete block.

    A 51 year-old Japanese man who had undergone surgical correction of an atrial septal defect at the age of 18 years old was referred to our institute for evaluation of his atrial arrhythmia. The conventional electrophysiological study was combined with a new technique utilizing an isopotential and isochronal mapping system (QMS) to visualize the electrical signals recorded with a 64-electrode basket catheter. Using this system, an intra-atrial reentrant tachycardia (IART) was demonstrated. The isopotential map recorded with the QMS (QMS-isoP) rapidly revealed a clockwise global reentrant circuit in the mid free wall of the right atrium and a narrowest activation isthmus between the lower end of the atriotomy scar and the inferior vena cava (IVC). After confirming entrainment with concealed fusion at the lower end of the atriotomy scar, radiofrequency energy was delivered linearly from this site to the IVC by slowly dragging the catheter. The elimination of the IART was defined by the QMS-isoP which demonstrated bidirectional block during pacing from both sides of the ablated linear lesion. The conventional technique of entrainment with concealed fusion combined with the QMS-isoP may result in a highly sophisticated method for identifying global reentrant circuits and for defining bidirectional block after eliminating the IART.
- - - - - - - - - -
ranking = 0.85714285714286
keywords = block
(Clic here for more details about this article)

10/81. Successful treatment of anteroseptal accessory pathways by transvenous cryomapping and cryoablation.

    Radiofrequency is the most commonly used energy source for the treatment of cardiac arrhythmias. Despite its high success rate, radiofrequency energy may sometimes present limitations, especially in case of anteroseptal atrioventricular accessory pathways. In these patients, inadvertent atrioventricular block may occur during or after the procedure and a high recurrence rate of conduction over the accessory pathway is observed. Since the late 1970s, cryosurgery has been an integral part of the management of cardiac arrhythmias, and recently, animal and clinical studies demonstrated the feasibility and safety of applying percutaneous catheter cryoablation technology. These studies also showed that reversible cryomapping of high-risk arrhythmogenic sites can be performed before creating permanent lesions. In this preliminary report, we describe the successful use of percutaneous cryoablation for the permanent interruption of conduction over anteroseptal accessory pathways.
- - - - - - - - - -
ranking = 0.14285714285714
keywords = block
(Clic here for more details about this article)
| Next ->



We do not evaluate or guarantee the accuracy of any content in this site. Click here for the full disclaimer.