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At least 73 records · Page 4Linked to original sources
PubMed1986

Long-term management of ventricular tachycardia by implantable automatic burst tachycardia-terminating pacemakers.

This report describes the long-term follow-up of two patients who received implantable automatic burst tachycardia-terminating ventricular pacemakers for the treatment of drug-refractory sustained ventricular tachycardia. After implantation, both pulse generators continued to terminate ventricular tachycardia without any major complications. In one patient, after three years, many episodes of ventricular tachycardia were slower than the tachycardia-detection criterion rate of 137 per minute; ventricular tachycardia was then terminated by chest wall stimulation that activated the burst function of the pacemaker. In this particular patient, the pulse generator was removed after four and one-half years and replaced with a DDD system because of the pacemaker syndrome and attacks of ventricular tachycardia, often at a rate of about 100/minute. In the second patient, the pacemaker continued to terminate ventricular tachycardia for over five and one-half years as determined by the repeated activation of the flag (memory) function of the pacemaker indicating detection of tachycardia by the pulse generator and resultant delivery of burst pacing.

Aged↗
PubMed2001

Slow pathway modification for atrioventricular node re-entrant tachycardia: fast junctional tachycardia predicts adverse prognosis.

OBJECTIVE: To examine the cycle length of the junctional tachycardia often seen during successful slow pathway ablation for atrioventricular (AV) node re-entrant tachycardia, to determine whether shorter cycle lengths predict imminent atrioventricular block. DESIGN: Retrospective analysis of consecutive patients undergoing slow pathway modification. Intracardiac recordings were analysed after digital storage to determine the development of junctional tachycardia, its duration and maximum, minimum, and mean cycle length, occurrence of heart block, persistent slow pathway conduction, or later confirmed recurrence of AV node re-entrant tachycardia. SETTING: Regional cardiac centre. PATIENTS: 136 consecutive patients undergoing electrophysiological study found to have typical "slow-fast" AV node re-entrant tachycardia and subject to 137 slow pathway modification procedures. RESULTS: During successful temperature feedback controlled radiofrequency energy application, junctional tachycardia developed in 133 of 137 procedures. During ablation, 10 patients had evidence of AV block (first degree in seven patients and third degree in three), and 17 others had retrograde junctional atrial (JA) block. In these 27 patients, the junctional tachycardia was rapid, with a minimum (SD) cycle length 291 (47) ms. Conduction recovered quickly in all but two patients, one of whom required permanent pacing. Junctional tachycardia with normal AV and JA conduction in the other 111 patients was of a significantly slower minimum cycle length (537 (123) ms; p < 0.0001). CONCLUSIONS: Fast junctional tachycardia with cycle lengths under 350 ms seen during slow pathway modification is a predictor of conduction block, suggesting proximity to the compact node. Radiofrequency energy application should be terminated immediately to prevent development of AV block. An "auto cut off" facility for cycle lengths shorter than 350 ms could be built into radiofrequency ablation systems to increase safety.

Catheter Ablation↗
PubMed1989

[Combination use of an automatic anti-tachycardia pacemaker and an automatic implantable cardioverter-defibrillator in sustained recurrent ventricular tachycardia resistant to drugs].

We used the combination of an antitachycardia automatic ventricular pacemaker with the automatic implantable cardioverter-defibrillator in two patients with sustained, recurrent, drug-resistant ventricular tachycardias in whom a surgical ablation was not indicated. The indications for the combined use of the two systems were the possibility to control: a) the ventricular tachycardias with ventricular programmed stimulation; b) the arrhythmias which might eventually degenerate into ventricular flutter or fibrillation (as a result of anti-tachycardia pacing) with the defibrillator. To avoid any possible interference between the two systems we used the following protocol: a) endocardial bipolar pacing; b) the sensing electrodes of the defibrillator were placed as far as possible from the endocardial one; c) a suitable programming of the pacemaker output; d) a careful selection of the anti-tachycardia pacing programme (burst rate inferior to the cut-off rate of the cardioverter-defibrillator and/or a duration of the burst pacing inferior to the arrhythmia sensing time of the defibrillator); e) use of cardioverter-defibrillators with a high cut-off rate. We never observed, during the follow-up (11 and 4 months, respectively), interference between the two systems. Both patients had ventricular tachycardia recurrences (51 and 3 episodes, respectively). The arrhythmias were correctly detected and interrupted by the pacemaker without the intervention of the defibrillator. These data confirm the feasibility of the combined use of the two systems in patients with ventricular tachycardias and, in selected cases, this approach is preferable. The anti-tachycardia pacemaker counteracts some limitations of the defibrillators available at present. It offers a protection against bradyarrhythmias and allows a more precise storage of arrhythmic events. The anti-tachycardia pacemaker often controls ventricular tachycardias without the intervention of the defibrillator, thus giving the same a longer life-span and allowing patients to avoid the shock.

Aged↗
PubMed2005

Coexistence of atrioventricular nodal reentrant tachycardia and idiopathic left ventricular outflow-tract tachycardia.

Double tachycardia is a relatively rare condition. We describe a 21 year old woman with history of frequent palpitations. In one of these episodes, she had wide complex tachycardia with right bundle branch and inferior axis morphology. A typical atrioventricular nodal tachycardia was induced during electrophysiologic study, aimed at induction of clinically documented tachycardia. Initially no ventricular tachycardia was inducible. After successful ablation of slow pathway, a wide complex tachycardia was induced by programmed stimulation from right ventricular outflow tract. Mapping localized the focus of tachycardia in left ventricular outflow tract and successfully ablated via retrograde aortic approach. During 7 month's follow-up, she has been symptom free with no recurrence. This work describes successful ablation of rare combination of typical atrioventricular nodal tachycardia and left ventricular outflow tract tachycardia in the same patient during one session.

Journal Article↗
PubMed1991

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

The authors describe a patient who experienced recurrent wide-complex and narrow-complex tachycardias during exercise. Electrophysiologic testing in the resting state revealed dual atrioventricular (AV) nodal pathways. AV nodal reentrant tachycardia was inducible by ventricular premature stimulation but was always nonsustained, terminating with block in the anterograde slow pathway. During isoproterenol infusion, runs of ventricular tachycardia occurred frequently, and spontaneously initiated sustained AV nodal reentrant tachycardia. Exercise testing also provoked ventricular tachycardia and sustained AV nodal reentrant tachycardia. The patient was effectively treated with a combination of atenolol and verapamil. This case is an unusual example of a catecholamine-induced arrhythmia, possibly due to triggered activity (exercise-induced ventricular tachycardia), initiating an arrhythmia due to reentry (AV nodal reentrant tachycardia).

Catecholamines↗
PubMed1991

Flecainide acetate treatment of paroxysmal supraventricular tachycardia and paroxysmal atrial fibrillation: dose-response studies. The Flecainide Supraventricular Tachycardia Study Group.

The dose-response relations for efficacy and tolerance of the antiarrhythmic drug flecainide acetate were studied in 28 patients with paroxysmal supraventricular tachycardia (Group 1) and 45 patients with paroxysmal atrial fibrillation or flutter (Group 2). Recurrent symptomatic tachycardia was documented with use of transtelephonic electrocardiographic recording. Patients received flecainide in doses of 25, 50, 100 and 150 mg twice daily and placebo for 1 month treatment periods. Among 14 patients in Group 1 who qualified for efficacy analysis, 4 (29%) had no tachycardia while taking placebo. The number with no tachycardia increased with progressively larger flecainide doses; with the 150 mg twice daily dose, 12 (86%) of 14 patients had no tachycardia (p less than 0.01 for overall differences among all treatments). Among 28 patients in Group 2, 2 (7%) had no tachycardia while taking placebo. The number with no tachycardia also increased with progressively larger flecainide doses; with the 150 mg twice daily dose, 17 (61%) of 28 patients had no tachycardia (p less than 0.01 for overall differences among all treatments). Noncardiac adverse experiences were the leading cause of premature study discontinuation during flecainide treatment periods (five patients in Group 1 and six patients in Group 2).

Adult↗
PubMed1995

Heart rate variability and inappropriate sinus tachycardia after catheter ablation of supraventricular tachycardia.

Sinus tachycardia has been reported after radiofrequency catheter ablation of supraventricular tachycardia. Frequently, these patients require beta-blocking agents for symptomatic control. The purpose of this study was to evaluate prospectively the incidence of inappropriate sinus tachycardia and heart rate variability after ablation of atrioventricular nodal reentrant tachycardia and accessory pathways. Patients undergoing ablation had 24-h ambulatory monitoring ECG (Holter) performed before the procedure, on the day of the ablation, and 3 months afterwards. There were 170 patients, mean age 48 +/- 23 years; 93 were female. A complete study of the 24-h Holter with analysis of heart rate variability: SD, rMSSD, pNN50, high and low frequency was obtained. There was a low prevalence of inappropriate sinus tachycardia after the ablation procedure (10 of 170 patients: five with four atrioventricular nodal reentry, with posteroseptal accessory pathways and one of the latter following ablation of the left accessory pathway). There was no modification of time and frequency domain parameters of heart rate variability in the remaining patients who underwent radiofrequency ablation. Holter monitoring 3 months after ablation showed that parameters of heart rate and heart rate variability had normalized in patients who had developed inappropriate sinus tachycardia. Inappropriate sinus tachycardia may be initiated by both radiofrequency ablation of atrioventricular nodal reentrant tachycardia and radiofrequency ablation of posteroseptal accessory pathways. Specific damage to the posteroseptal region is responsible for these changes, which usually recover spontaneously after 3 months.

Adult↗
PubMed1996

[Value of old and new electrocardiography criteria for differential diagnosis between ventricular tachycardia and supraventricular tachycardia with bundle branch block].

In 240 tachycardias with wide QRS-complex (> or = 120 ms), the value of the "old" ECG criteria published in 1978 by Wellens and coworkers was compared to the "new" ECG criteria published in 1991 by Brugada and coworkers for the differential diagnosis of tachycardias with wide QRS-complex. As main result of the study, it could be demonstrated that with the old as well as with the new ECG criteria a sensitivity of more than 90% for the correct diagnosis ventricular tachycardia can be reached. The specificity of the old and new ECG criteria for the diagnosis ventricular tachycardia is 70% and 72% for tachycardias with right bundle branch block configuration and 87% each for tachycardias with left bundle branch block configuration. The combined use of the old and the new ECG criteria in this study could not increase sensitivity and specificity for the diagnosis of ventricular tachycardia. Therefore, it does not appear to be important for the differential diagnosis of tachycardias with wide QRS-complex whether the old or the new step diagnostic criteria are being used, but that either the old or the new ECG criteria are being used correctly.

Adult↗
PubMed1984

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.

To evaluate factors playing a role in initiation of atrioventricular (AV) nodal reentrant tachycardia utilizing anterogradely a slow and retrogradely a fast conducting AV nodal pathway, 38 patients having no accessory pathways and showing discontinuous anterograde AV nodal conduction curves during atrial stimulation were studied. Twenty-two patients (group A) underwent an electrophysiologic investigation because of recurrent paroxysmal supraventricular tachycardia (SVT) that had been electrocardiographically documented before the study. Sixteen patients (group B) underwent the study because of a history of palpitations (15 patients) or recurrent ventricular tachycardia (one patient); in none of them had SVT ever been electrocardiographically documented before the investigation. Twenty-one of the 22 patients of group A demonstrated continuous retrograde conduction curves during ventricular stimulation. In 20 tachycardia was initiated by either a single atrial premature beat (18 patients) or by two atrial premature beats. Fifteen of the 16 patients of group B had discontinuous retrograde conduction curves during ventricular stimulation, with a long refractory period of their retrograde fast pathway. Tachycardia was initiated by multiple atrial premature beats in one patient. Thirteen out of the remaining 15 patients received atropine. Thereafter tachycardia could be initiated in three patients by a single atrial premature beat, by two atrial premature beats in one patient, and by incremental atrial pacing in another patient. In the remaining eight patients tachycardia could not be initiated. Our observations indicate that the pattern of ventriculoatrial conduction found during ventricular stimulation is a marker for ease of initiation of AV nodal tachycardia in patients with discontinuous anterograde AV nodal conduction curves.

Adolescent↗
PubMed1977

Effect of procainamide, propranolol and verapamil on mechanism of tachycardia in patients with chronic recurrent ventricular tachycardia.

The effect of short-term intravenous administration of procainamide (12 patients), propranolol (4 patients) and verapamil (4 patients) was studied in 12 patients with chronic recurrent sustained ventricular tachycardia. In all patients tachycardia could reproducibly be initiated and terminated with programmed electrical stimulation of the heart. Procainamide (1) lengthened the effective refractory period of the right ventricle, (2) affected the tachycardia zone, (3) reduced ventricular rate during tachycardia, and (4) lengthened the interval between the tachycardia-initiating premature ventricular beat and the first QRS complex of tachycardia. No effect on the refractory period of the right ventricle or the mechanism of tachycardia was seen after administration of propranolol or verapamil. Apart from their therapeutic implications these data suggest that it may be possible to use drugs to study mechanisms of ventricular tachycardia in the human heart.

Adult↗
PubMed1984

Entrainment of atrioventricular nodal reentrant tachycardias during overdrive pacing from high right atrium and coronary sinus. With special reference to atrioventricular dissociation and 2:1 retrograde block during tachycardias.

Entrainment was attempted during electrophysiologic evaluation of 8 patients with atrioventricular (AV) nodal reentrant tachycardia. Entrainment could be performed while pacing from the high right atrium in 35 of 35 episodes, from proximal coronary sinus in 9 of 21 episodes and from distal coronary sinus in 10 of 20 episodes. The minimal rates required were 8 to 40 beats/min faster than those of the tachycardias. That the atria (as defined in electrophysiologic studies) were not a necessary component of the reentry circuit was suggested by the occurrence, during tachycardia, of short episodes of AV dissociation and of 1 episode of 2:1 retrograde block. For the tachycardia to be interrupted, the pacing rate usually had to be slightly faster than that required to entrain, as well as sufficiently rapid to produce anterograde block of an atrial impulse in the slow AV nodal pathway. Moreover, termination of tachycardia apparently was a function of the pacing site. In some episodes, either because of a proximity effect or because of a preferential input into the upper common pathway, coronary sinus pacing terminated the tachycardia at slower rates or with fewer stimuli than high right atrial pacing. Thus, patients with drug-resistant AV nodal reentrant tachycardias may benefit from recently introduced pacing techniques for termination of tachycardia through entrainment.

Adolescent↗
PubMed1992

Effects of sotalol on the signal-averaged electrocardiogram in patients with sustained ventricular tachycardia: relation to suppression of inducibility and changes in tachycardia cycle length.

OBJECTIVES: This study examines the effects of sotalol on the signal-averaged electrocardiogram (ECG) in patients with spontaneous and inducible sustained ventricular tachycardia and correlates these findings with the effect of sotalol on tachycardia inducibility and tachycardia rate. BACKGROUND: Standard electrocardiography generally does not detect any change in the duration of the QRS complex resulting from sotalol therapy. However, the signal-averaged ECG is more sensitive than the standard ECG for detecting changes in QRS duration induced by antiarrhythmic drugs and can also detect changes in late potential duration. METHODS: Signal-averaged electrocardiography was performed before therapy in 30 patients with spontaneous and inducible ventricular tachycardia, and both electrophysiologic study and a signal-averaged ECG were repeated during therapy with d,l-sotalol. RESULTS: During sotalol therapy the signal-averaged QRS duration decreased by 2.6 +/- 6.6 ms in the 11 patients with no inducible tachycardia during therapy, whereas it increased by 3.8 +/- 5.8 ms (p = 0.01) in the 19 patients with inducible tachycardia during therapy. In the latter group there was a significant positive correlation between prolongation of tachycardia cycle length and prolongation of late potential duration by sotalol (r = 0.56, p = 0.01). CONCLUSIONS: Sotalol can alter QRS and late potential duration as measured by the signal-averaged ECG. Prolongation of QRS duration or late potential duration may reflect a slowing of conduction by sotalol that may interfere with this agent's antiarrhythmic efficacy and slow ventricular tachycardia.

Capsules↗
PubMed2000

Simultaneous alterations of QRS configuration and tachycardia cycle length during radiofrequency ablation of idiopathic left ventricular tachycardia.

Idiopathic left ventricular tachycardia is characterized by a QRS morphology of right bundle branch block pattern and left axis deviation. Alterations in the QRS configuration and tachycardia cycle length, as well as shifting of the earliest activation site occurred after eliminating the original tachycardia by radiofrequency current in an 18-year-old man with idiopathic left ventricular tachycardia. Activation mapping and entrainment mapping during tachycardia identified 2 putative tachycardia exits, 15 mm apart. Elimination of both tachycardias was accomplished after applying radiofrequency current to each exit separately. We proposed that the first radiofrequency application might have altered the exit site and the zone of slow conduction adjacent to the exit site, such that the ventricular tachycardia had a different QRS morphology and became slower in this patient.

Adolescent↗
PubMed1998

Double-wave reentry in orthodromic atrioventricular reciprocating tachycardia: paradoxical shortening of the tachycardia cycle length with development of ipsilateral bundle branch block.

INTRODUCTION: Attempts to terminate reentrant tachyarrhythmias by rapid pacing may accelerate the tachycardia. One mechanism for acceleration is double-wave reentry, where two simultaneous wavefronts travel around the same circuit. METHODS AND RESULTS: We report pacing acceleration of AV reciprocating tachycardia (AVRT) due to double-wave reentry in a patient with Wolff-Parkinson-White syndrome. The patient had presented with atrial fibrillation and rapid conduction across a left lateral bypass tract. Intravenous procainamide was given during electrophysiologic study because of incessant atrial fibrillation and restored sinus rhythm. Orthodromic AVRT was induced and attempts to terminate the AVRT with right ventricular pacing initiated two alternate tachycardias, both with a left bundle branch block (LBBB) morphology. The first tachycardia, as expected for bundle branch block ipsilateral to the bypass tract, had a longer cycle length (CL) than the original tachycardia (366 msec compared to 297 msec). The second tachycardia had a paradoxically shorter CL, 238 msec compared to 297 msec. Electrogram analysis revealed that the circuit traversed by the accelerated LBBB tachycardia was the same as the slower LBBB tachycardia. The activation sequence revealed two independent wavefronts, traversing this common circuit. As described previously in experimental models, double-wave reentry was initiated when an antidromic-stimulated impulse blocked before colliding with the previous orthodromic impulse, thus allowing two orthodromic impulses to circulate within the circuit. CONCLUSION: We speculate that conduction slowing by procainamide combined with the intrinsic AV nodal delay resulted in the necessary increase in the excitable gap required to develop double-wave reentry. This is the first description of sustained double-wave reentry in humans.

Adult↗