Impact of transesophageal electrophysiologic study to elucidate the mechanism of arrhythmia on children with supraventricular tachycardia and no preexcitation.

An electrophysiologic study (EPS) of children and teenagers with paroxysmal supraventricular tachycardia (SVT) and normal electrocardiography (ECG) in sinus rhythm was evaluated. Generally, EPS is performed only before paroxysmal SVT ablation in these patients. In this study, 140 patients (mean age, 15 ± 3 years) with normal ECG in sinus rhythm were studied for SVT by a transesophageal route in baseline state and after isoproterenol. Idiopathic left or right ventricular tachycardia was diagnosed in four patients (3 %). Anterograde conduction over an atrioventricular (AV) left lateral (n = 10) or septal (n = 9) accessory pathway (AP) was noted in 19 patients (13.5 %) at atrial pacing. Orthodromic AV reentrant tachycardia (AVRT) was induced in these children. Five of the patients had a high rate conducted over AP (>240 bpm in baseline state or >290 bpm after isoproterenol). Two of the patients (a 10-year-old girl with well-tolerated SVT and a 17-year-old with syncope-related SVT) had the criteria for a malignant form with the induction of atrial fibrillation conducted over AP at a rate exceeding 290 bpm in baseline state. Of the 140 patients, 74 (53 %) had typical AV node reentrant tachycardia (AVNRT), nine had atypical AVNRT (6 %), 1 had atrial tachycardia (0.7 %), and 33 (23.5 %) had AVRT related to a concealed AP with only retrograde conduction. Electrophysiologic study is recommended for children with paroxysmal SVT and normal ECG in sinus rhythm. The data are helpful for guiding the treatment. Ventricular tachycardia or atrial tachycardia can be misdiagnosed. Masked preexcitation syndrome with anterograde conduction through AP was present in 13.5 % of the patients, and 1.4 % had a malignant preexcitation syndrome.

Sex-related differences in peri- and post-ablation clinical data for patients with atrial flutter.

UNLABELLED: Sex-related differences were not reported for the atrial flutter (AF). The purpose of the study was to look for the influence of gender on indications, clinical data and long-term results of AFl ablation. METHODS: 985 patients, [227 females (23%)] were referred for radiofrequency AFl ablation. Clinical history, echocardiography were collected. Patients were followed from 3 months to 10 years. RESULTS: Age of women and men was similar (65.5 ± 12 vs 64 ± 11.5 years). Underlying heart disease (HD) was as frequent in women as men (77.5 vs 77%), but women had more congenital HD (10 vs 2%;p<0.001), valvular HD (18 vs 10%;p<0.002), hypertensive HD (24 vs 18%;p<0.05), and less chronic lung disease (5 vs 10%;p<0.01), and ischemic HD (5 vs 20%;p<0.001). Atrial fibrillation (AF) history was more frequent in women (36 vs 27%;p<0.001). AFl-related tachycardiomyopathy (4.5 vs 8%;p<0.03) was more frequent, but 1/1 AFl (10 vs 6%;p=NS) as frequent. Failure of ablation (16 vs 10%;p<0.01), ablation-related major complications (3.5 vs 0.9%;p<0.005) were more frequent in women. After 3 ± 3 years, AFl recurrences were as frequent in women and men (10 vs 14%), AF occurrence more frequent in women (34 vs 19.5%; p<0.001). After excluding patients with previous AF, AF risk remained higher in women (19 vs 12%; p<0.004). CONCLUSIONS: In patients admitted for ablation, AFL was less common in women than in men, despite similar age and similarly prevalent HD. More than men, women had frequent AF history, a higher risk of failure of ablation and AFl ablation-related major complications and a higher risk of AF after ablation.

Is ablation of atrial flutter always safe?

BACKGROUND: Radiofrequency ablation of typical atrial flutter is largely used and is considered as safe. The purpose of the study was to evaluate the prevalence and the causes of severe adverse event (AE) following atrial flutter ablation. METHODS: Ablation of typical flutter was performed by conventional method with an 8-mm-tip electrode catheter, a maximum power of 70 W, and a maximum target temperature of 70° for 60 seconds in 883 patients, (685 males and 198 females aged from 18 to 93 years [64 ± 11.5]; 664 had heart disease [HD]). RESULTS: AE occurred in 44 patients (5%). AE was life threatening in 14 patients: poorly tolerated bradycardia (transient complete atrioventricular block [AVB] or sinus bradycardia [SB] <40 beats per minute) associated with cardiac shock and acute renal failure in five patients, tamponade (n = 1), bleeding leading to death (n = 1), various AE-related deaths (n = 2), ventricular tachycardia-related death (n = 1), definitive complete AVB (n = 3), and right coronary artery occlusion-related complete AVB (n = 1). Less serious AE occurred in 30 patients: transitory major SB or second- or third-degree AVB (n = 23), bleeding (n = 4), transient ischemic attack (n = 1), and various AE (n = 2). Most of the bradycardia was related to ß-blockers or other antiarrhythmic drugs used to slow atrial flutter. Factors of AE were female gender (36% vs 22%, P < 0.02) and the presence of ischemic (P < 0.03) or valvular HD (P < 0.01). CONCLUSIONS: AE following atrial flutter ablation occurred in 5% of patients. Most of them are avoidable by control of anticoagulants and arrest of rate-control drugs used to slow the rate of atrial flutter.

[Comparison of patients with paroxysmal junctional tachycardia and syncope with those without syncope]. / Comparaison des sujets ayant des tachycardies jonctionnelles paroxystiques et des syncopes avec des sujets sans syncopes.

INTRODUCTION: The purpose of the study was to determine the possible mechanisms of presyncope in patients who have paroxysmal junctional tachycardias (PJT) and a normal surface ECG between tachycardias. METHODS: Among 419 patients consecutively recruited for PJT, aged from 10 to 88 years (47+/-19), 78 of them had presented at least one syncope; they had a normal ECG in sinus rhythm. Transesophageal programmed atrial stimulation was performed using one and two atrial extrastimuli delivered in control state and if necessary after infusion of 20-30 microg of isoproterenol; arterial blood pressure was monitored; vagal maneuvers and tilt test (n=25) were performed; echocardiogram was systematic. RESULTS: Age, sex, method of induction, tachycardia mechanism and the mean heart rate in tachycardia were similar in patients with and without syncope. Syncope was related to a vagal reaction induced by the PJT in 31 patients, to a fast rate during PJT in 15 patients, to a sinus node dysfunction in six patients, to a coronary ischemia in five patients, to a tetany induced by PJT in three patients, to an advanced age in three patients, to multiple causes in three patients and remained unexplained in eight patients. Radiofrequency ablation of reentrant circuit, performed in 28 patients, suppressed syncope in 26 of them. CONCLUSION: Presyncope or syncope occurred in 18% of patients who had a history of paroxysmal junctional tachycardia. Several mechanisms were implicated; the most frequent causes were coronary ischemia or sick sinus syndrome in old patients, vasovagal reaction or fast rate in tachycardia or tetany in patients of all ages.

Wolff-Parkinson-White syndrome in the elderly: clinical and electrophysiological findings.

BACKGROUND: Screening for Wolff-Parkinson-White (WPW) syndrome is recommended in children and young adults. The aim of this study was to evaluate the clinical and electrophysiological characteristics of patent WPW syndrome in subjects > or =60 years of age. METHODS: Four-hundred and fifty-nine consecutive patients with WPW syndrome, aged 8-80 years, were recruited; 32 (7%) of these patients were > or =60 years of age. The clinical, electrophysiological and therapeutic data for these patients were evaluated. RESULTS: Sixteen men and 16 women, aged 60-81 years (67+/-4.5), were admitted for resuscitated sudden death (1), rapid atrial fibrillation (4), syncope (4), or junctional tachycardia (13); 10 patients were asymptomatic (10). Left lateral bundles of Kent were detected more frequently in patients over 60 years (56%) than in those<60 years of age (40.5%). Reciprocal tachycardia was induced in 58% of subjects<60 years of age and 53% of those > or =60 years old (difference not significant); atrial fibrillation was more frequent in subjects > or =60 years of age (37.5% vs. 19%) (p<0.05). The incidence of malignant forms of WPW syndrome was identical in older and younger subjects. Ablation of the accessory pathway was indicated 18 times; effective ablation of a left bundle of Kent required a second intervention more often in patients > or =60 years of age (22% vs. 5%) (p<0.05). CONCLUSION: WPW syndrome is not uncommon in subjects over 60 years of age (7%). Left lateral accessory pathways, that have similar conduction properties to those in much younger subjects, are common. Ablation of the bundle of Kent is often difficult but is indicated in symptomatic subjects or those with more serious forms of WPW syndrome.

Interest of non-invasive and semi-invasive testings in asymptomatic children with pre-excitation syndrome.

AIMS: To determine the feasibility and the results of exercise testing (ET) and electrophysiological study (EPS) in outpatient asymptomatic children with a Wolff-Parkinson-White (WPW) syndrome. METHODS AND RESULTS: Exercise testing and transesophageal EPS were performed in 55 outpatient asymptomatic children aged 6 to 19 years old (14 +/- 3) with WPW. Wolff-Parkinson-White persisted during maximal exercise. Isoproterenol was not required in five children younger than 10 years old, because they developed a catecholaminergic sinus tachycardia. Maximal rate conducted through accessory pathway (AP) was higher in children younger than 16 years old than in teenagers (P < 0.05). Atrioventricular re-entrant tachycardia (AVRT) was induced in six children; atrial fibrillation (AF) in 12 children. The induction of tachycardias and the dangerous forms (18%) were not influenced by age. After 5 +/- 1 years, one child, 12 year old with inducible rapid AF, had a sudden cardiac arrest; two children became symptomatic after ablation. CONCLUSIONS: Transesophageal EPS was required to determine the prognosis of asymptomatic WPW in children. The maximal rate conducted in AP was higher in children younger than 16 years old than in teenagers; other data did not differ. AVRT was rare; 71% of children had no inducible arrhythmia and were authorized to resume physical activities.

Supraventricular tachyarrhythmia as a cause of sudden cardiac arrest.

INTRODUCTION: Supraventricular tachyarrhythmias (SVTA) are an accepted cause of cardiac arrest in patients with Wolff-Parkinson-White syndrome (WPW) and hypertrophic cardiomyopathy but their participation in other conditions is less well understood. The purpose of the study was to examine the role of SVTA in sudden cardiac arrest (SCA) by comprehensive evaluation of patients successfully resuscitated from SCA. METHODS: A total of 169 survivors of SCA in the absence of acute myocardial infarction underwent systematic evaluation that included echocardiography, Holter monitoring, coronary angiography and electrophysiological study (EPS) with additional testing in selected cases using provocative drug testing with isoproterenol, ajmaline or ergonovine. RESULTS: SVTA was found as the only possible cause or as the cause facilitating SCA in 29 patients: (1) 3 had a WPW syndrome related to accessory pathway with short refractory period; (2) for 12 patients, SVTA was the cause of cardiovascular collapse; heart disease (HD) was present in 11 cases, but disappeared in two of four with dilated cardiomyopathy after the restoration of sinus rhythm; (3) in 14 patients, SVTA degenerated either in a VF or ventricular tachycardia (VT); HD was present in 12 cases, but disappeared in one; two had no HD and recurrent similar arrhythmia was documented by cardiac defibrillator in one of them. SVTA induced coronary ischemia was the main cause of SCA. CONCLUSION: Rapid SVTA was a cause of SCA, either by cardiovascular collapse or by the degeneration in VT or VF. The complication generally occurred in patients with advanced HD or with rapid SVTA-induced cardiomyopathy and rarely in patients without HD. The incidence of SVTA as the only cause or the facilitating cause of SCAs is probably underestimated, because it is difficult to prove.

[Association of Wolff-Parkinson-White syndrome with isolated non-compaction of the left ventricle: a case report]. / Association du syndrome de Wolff-Parkinson-White a une non-compaction isolée du ventricule gauche. A propos d'un cas.

The Wolff-Parkinson-White syndrome (WPW) may be associated with a number of cardiac pathologies, especially congenital disease, in 7.5 to 17% of cases. The authors report a rare association of the WPW syndrome with two Kent bundles, right and left septal, with non-compaction of the left ventricle in a 52 year old man. This was a chance finding during systematic echocardiography after ablation, and confirmed by cardiac MRI. The patient was asymptomatic.

[Feasibility and significance of a transoesophageal electrophysiological investigation in children and adolescents with Wolff-Parkinson-White syndrome]. / Faisabilité et intérêts de l'étude électrophysiologique par voie transoesophagienne dans le syndrome de Wolff-Parkinson-White de l'enfant et de l'adolescent.

UNLABELLED: An electrophysiological investigation is the most reliable means of detecting malignant forms of Wolff-Parkinson-White syndrome (WPW). However, an endocavity investigation is an invasive procedure, especially in young subjects with few symptoms. The aim of this study was to examine the feasibility and results of an electrophysiological study performed by the transoesophageal route in children with WPW. The study was performed in 70 children aged between 11 and 19 years (mean 15 +/- 3) with an obvious ECG appearance of WPW: 13 had dizziness or syncope (group I), 25 had tachycardia (group II) and 32 were asymptomatic (group III). The ages were similar in all three groups. The transoesophageal electrophysiological investigation without premedication consisted of atrial stimulation at increasing frequencies and programmed atrial stimulation using one and two extra stimuli delivered in the basal state and after infusion of 2 to 5 microg of isoproterenol. RESULTS: The investigation was completed in all the children except one in group II. A paroxysmal junctional tachycardia was induced in 7 group I children (54%), 22 in group II (92%) and 4 in group III (12.5%). Atrial fibrillation lasting more than one minute was induced in 7 group I children (54%), 6 in group II (25%) and 6 in group III (19%). The percentage of malignant forms combining rapid conduction in the bundle of Kent at a rate of more than 240/min in the basal state or more than 300/min with isoproterenol, and atrial fibrillation was 54% in group I, 21% in group II, and 22% in group III. In conclusion, a transoesophageal electrophysiological investigation was possible as an outpatient procedure in children older than 10 years, and allowed the detection of potentially serious forms whatever the indication for the investigation, with nevertheless a significantly higher incidence in those presenting with dizziness or syncope. The incidence of 22% for potentially malignant forms in asymptomatic children provides an incentive to recommend an ECG in all children older than 10 years participating in an active sport in order to detect WPW and to propose oesophageal investigation.

[New systems of mapping and navigation in electrophysiology]. / Nouveaux systèmes de cartographie et de navigation en électrophysiologie.

The indications of radiofrequency ablation of arrhythmias have considerably increased since the introduction of the technique in the early 1990s. Interventional rhythmologists now treat arrhythmias which are more and more complex by their mechanism. This requires accurate representation of the ablation catheter position and the integration of spatial and temporal data to identify the arrhythmogenic substrate. The systems of mapping and navigation developed over the last ten years are important tools for interventional rhythmologists. They are very useful for the identification of complex arrhythmogenic substrates which require "individualised" ablations in specific cases. The aim of this article is to review different systems of mapping, and/or navigation currently on the market and their principal characteristics without entering into the details of their use in interventional electrophysiology.

Wide QRS complex tachycardia. Rapid method of prognostic evaluation.

UNLABELLED: A wide QRS complex tachycardia suggests a ventricular tachycardia (VT); but supraventricular tachycardia (SVT) is also possible. Some authors reported on the electrocardiographic signs for the differential diagnosis of VT and SVT with aberrancy. Frequently these signs are debatable and the diagnosis is uncertain. The purpose of the study was to evaluate the interest of a non-invasive study by transesophageal route for the evaluation of the nature of a wide QRS complex tachycardia in which a reliable ECG algorithm does not permit to distinguish VT from SVT with aberrancy. METHODS: Esophageal electrophysiologic study (EPS) was performed in 53 patients, aged from 16 to 85 years without bundle branch block (BBB) in sinus rhythm, but with wide-QRS tachycardia. The protocol consisted of atrial pacing at progressively higher rates and then programmed stimulation with one and two extrastimuli in control state and after isoproterenol infusion. Intracardiac EPS was performed in 49 of them. RESULTS: (1) Study was negative in nine patients; intracardiac EPS remained negative in four of them, induced a VT in five; (2) clinical tachycardia was induced in 44 patients: (a) in 29 of them, atrial pacing induced a BBB similar to aberrancy noted in tachycardia and the diagnosis of SVT with aberrancy was made; (b) in 15 patients, QRS complex remained narrow during atrial pacing; the diagnosis of VT was made in presence of AV dissociation and confirmed by intracardiac study. VT was induced by atrial or ventricular stimulation or was spontaneous during isoproterenol infusion. VT mechanism were bundle branch reentry [Am. J. Cardiol. 65 (1990) 322], verapamilsensitive VT [Am. J. Cardiol. 65 (1990) 322], catecholamine-sensitive VT [J. Cardiovasc. Electrophysiol. 7 (1996) 2]. Two patients had tachycardias of both natures either supraventricular or ventricular. CONCLUSION: Esophageal EPS was a safe, rapid and economic means to evaluate the mechanism of wide QRS tachycardia in 84% of patients; atrial pacing at progressively higher rates is very simple to reproduce the aberrancy of similar morphology in those patients who had wide-QRS tachycardia related to a SVT with aberrancy. If atrial pacing did not exactly reproduce the aberrancy in tachycardia, a VT should be suspected.

[Does syncope change the results of programmed ventricular stimulation in patients with previous myocardial infarction?]. / La syncope change-t-elle les résultats de la stimulation ventriculaire programmée chez les patients ayant un antécédent d'infarctus du myocarde?

UNLABELLED: The induction of a ventricular tachycardia (VT) after myocardial infarction (MI) is associated with a high risk of VT and sudden death (SD) in asymptomatic patients; the purpose of the study was to know if syncope modifies the results of programmed ventricular stimulation (PVS) and the clinical consequences. METHODS: PVS using two and three extra stimuli delivered in two sites of right ventricle was performed in 1057 patients without spontaneous VT or resuscitated SD at least 1 month after an acute MI; 836 patients (group I) were asymptomatic and were studied for a low ejection fraction or nonsustained VT on Holter monitoring or late potentials; 228 patients (group II) were studied for unexplained syncope. The patients were followed up to 5 years of heart transplantation. RESULTS: Sustained monomorphic VT (< 280 b/min) was induced in 238 group I patients (28%) and 62 group II patients (29%); ventricular flutter (VT > 270 b/min) or ventricular fibrillation (VF) was induced in 245 group I patients (29%) and 42 group II patients (18%) (P < 0.05); PVS was negative in 353 group I patients (42%) and 124 (55%) group II patients (NS). The patients differ by their prognosis; cardiac mortality was 13% in group I patients and 34% in group II patients with inducible VT < 280 b/min (P < 0.01), 4% in group I patients and 13% in group II patients with inducible VF (P < 0.05), 5% in group I patients and 7% in group II patients with negative study (NS). In conclusion, syncope did not change the results of programmed ventricular stimulation after myocardial infarction. However, syncope increased significantly cardiac mortality of patients with inducible ventricular tachycardia, flutter or fibrillation.

[Causes and prognosis of syncope in patients with primary dilated cardiomyopathy]. / Causes et pronostic des syncopes chez les patients avec une cardiomyopathie dilatée primitive.

The causes of adverse prognosis of patients with primary dilated cardiomyopathy remain controversial. Classically, it is thought that syncope is associated with an increased risk of mortality. The aim of this study was to try and identify the causes and prognostic significance of syncope in patients with primary dilated cardiomyopathy. Sixty-five patients aged 31 to 80 with primary dilated cardiomyopathy were admitted for investigation of syncope. The average ejection fraction was 27 +/- 10%. Invasive and non-invasive investigations including complete electrophysiological investigations, were performed. Sustained monomorphic ventricular tachycardia was induced in 14 patients (21.5%), ventricular flutter or fibrillation was induced in 9 patients (14%), a supraventricular arrhythmia in 17 patients (26%), and a conduction defect alone or associated with another arrhythmia in 7 patients (11%). A pathological result of tilt testing was observed in 5 patients (8%). No cause of syncope could be demonstrated in 15 patients (23%). During follow-up (4 +/- 2 years) there was a mortality of 15% which was only correlated with the reduction in left ventricular ejection fraction. The authors conclude that there are many causes of syncope in primary dilated cardiomyopathy: ventricular arrhythmias represent only 35% of cases and do not impact on the prognosis; above all, left ventricular ejection fraction is the most important prognostic factor.

Transitory or permanent regular wide QRS complex tachycardia induced by atrial stimulation in patients without apparent heart disease. Significance.

OBJECTIVES: The purpose of the study was to evaluate the frequency of transitory or permanent bundle branch block (BBB) associated with a paroxysmal tachycardia induced by atrial stimulation in patients without heart disease and its significance. METHODS: Esophageal atrial stimulation was performed in 447 patients suspected to have supraventricular tachycardias (SVT). Sustained regular tachycardia was induced in all of them but three, either in control state (75%) or after administering isoproterenol. In 346 patients, only narrow complex SVTs were induced (77%); in 259 of them, the reentry occurred in the AV node and in remaining patients within a concealed accessory pathway. In 62 patients, a transitory functional BBB was recorded at the onset of the tachycardia (14%). In 33 of them, the reentry occurred in the AV node and in the remaining 29 patients within a concealed accessory pathway. In 36 patients (8%), a permanently wide QRS complex tachycardia was induced. Three patients had also inducible narrow complex SVT. Atrial pacing induced a BBB similar to the aberrancy in tachycardia in 22 patients: the reentry occurred in the AV node in 17 patients, within a concealed accessory pathway in three patients and in a Mahaim bundle in two patients. In other patients, QRS complex remained normal during atrial pacing: all 14 patients had a ventricular tachycardia (VT), either a verapamil-sensitive VT (n = 7) or catecholamine-sensitive VT (n = 4) or bundle branch reentry (n = 3). Followed from 2 to 12 years, the prognosis of these patients was excellent. CONCLUSION: Transitory BBB at the onset of an SVT is noted in 14% of the population, is more frequent in patients with accessory pathway reentrant tachycardia, but is helpful for this diagnosis in only 12% of cases. A regular tachycardia with permanent left or right bundle branch morphology induced by atrial stimulation in a patient without heart disease and without BBB during atrial pacing is due to a VT even if this patient has also narrow complex tachycardias. This mechanism does not affect the excellent prognosis of this population.

[Risk factors for cardiac mortality in cases of syncope with previous history of myocardial infarction]. / Facteurs de risque de mortalité cardiaque en cas de syncope et d'antécédents d'infarctus du myocarde.

Syncope is considered to be a clinical sign predictive of sudden death in patients with a previous history of myocardial infarction. The aim of this study was to determine the prognostic factors in this population. The study population included 228 patients with myocardial infarction over one month old and who had no documented ventricular tachycardia. The patients were referred for investigation of syncope. The left ventricular ejection fraction (LVEF) was measured by echocardiography or radionucleide technique. Complete electrophysiological study including programmed atrial and ventricular stimulation was performed in all cases. The patients were followed up for 6 months to 5 years or until cardiac transplantation (average 3+/-1 years). One hundred and nineteen patients had a LVEF <40% (Group I) and 109 patients had a LVEF >40% (Group II). Sustained monomorphic ventricular tachycardia (VT) with a rate inferior to 280/min was induced in 44 patients in Group I (37%) and in 18 patients in Group II (16.5%), p<0.05. Ventricular flutter or fibrillation was induced in 24 patients in Group I (19%) and in 19 patients in Group II (17%) (NS). Different causes of syncope (conduction disturbances, supraventricular tachycardia, increased vagal tone, severe coronary ischaemia) were found in 23 patients in Group I (19%) and 32 patients in Group II (29%) (NS). Syncope was unexplained in 43 patients in Group I (36%) and 40 patients in Group II (37%) (NS). The prognosis was very different. In Group I, the cardiac mortality was 49% in patients with inducible monomorphic VT <280/min, 35% in those with inducible ventricular flutter or fibrillation but only 9% in patients without inducible ventricular arrhythmias. In Group II, the prognosis was independent of the results of programmed stimulation and much better: cardiac mortality was 5.5% in patients with inducible VT, 5% in those with inducible ventricular flutter or fibrillation and 4% in patients without inducible ventricular arrhyhtmias. The authors conclude that LVEF is the most powerful predictor of cardiac mortality and sudden death in cases of syncope with a past history of myocardial infarction. The prognosis also depends on the results of programmed ventricular stimulation when the LVEF is inferior to 40%. Sustained monomorphic VT is the most frequently induced arrhythmia in this case and the prognosis of these patients is particularly poor. On the other hand, syncope does not appear to be a poor prognostic factor in the group with normal LVEF, even when it is possible to induce VT.

Correlation between electrogram morphology and standard criteria to validate bidirectional cavotricuspid block in common atrial flutter ablation.

AIM: Assessment of a bidirectional conduction block within the cavotricuspid isthmus (CTI) is critical during radiofrequency (RF) atrial flutter (AF) ablation. We investigated the use of bipolar atrial electrogram (BAE) morphology as an additional criterion identifying CTI block and tested it against two recognized criteria: differential pacing and reversal of the right atrial depolarization sequence during coronary sinus (CS) pacing. METHODS AND RESULTS: An RF ablation procedure was performed during 600 ms CS pacing in 100 consecutive patients with a common AF. BAE recorded along the CTI were continuously monitored. CTI conduction block was achieved by RF ablation in all patients and a clear change in BAE polarity in the Electrogram recorded by the dipoles located on the CTI and immediately lateral to the intended line of block (RS to QR pattern) associated with a confirmed CTI conduction block was observed in all cases. BAE morphology changes predicted bidirectional CTI conduction blocks with a 100% positive and a 100% negative predictive value. At a mean follow-up of 33 +/- 11 months, there was a 5% AF recurrence rate. CONCLUSIONS: Our study suggests that morphological changes in BAE recorded at sites lateral and adjacent to the target line of block may be used as a unique and robust criterion to validate CTI conduction block during AF ablation procedure.

[Syncope in patients with normal EKG and without cardiac disease: value of ambulatory esophageal electrophysiology in determining etiology]. / Syncopes chez des patients avec ECG normal sans cardiopathie: intérêt étiologique d'une étude électrophysiologique par voie oesophagienne en ambulatoire.

The aim of this study was to determine whether ambulatory oesophageal electrophysiological recordings are valuable in identifying the cause of syncope in patients with a normal ECG and without cardiac disease. One hundred and forty-five patients aged 16 to 88 years of age, without cardiac disease, and with a normal ECG without a documented arrhythmia, were examined for unexplained syncope: 55 patients complained of palpitations at the time of syncope. The electrophysiological study was carried out in the clinic with oesophageal recordings using a classical protocol: Wenckebach point and sinus node recovery time were determined; programmed atrial stimulation was used with delivery of 1 and 2 extra-stimuli on the basal rhythm and with 20/30 micrograms infusion of isoprenaline; blood pressure was monitored. The study was negative in 41 patients (28%). Sinus node dysfunction was observed in 9 patients (6%). A vaso-vagal reaction reproducing the symptoms was induced by isoprenaline in 21 patients (14.5%); a conduction defect was revealed in 2 cases (1%). Atrial fibrillation or tachycardia > 1 minute was induced in 22 patients (15%). Paroxysmal junctional tachycardia was induced in 50 patients (35%). Patients with a negative study were younger than those with sinus node dysfunction or atrial fibrillation (44 +/- 21, 71 +/- 9 and 63 +/- 14 years respectively). Treatment was guided by these results: cardiac pacing, antiarrhythmic therapy or radiofrequency ablation of the reentrant pathway were indicated and suppressed syncope in all but two patients. The authors conclude that electrophysiological studies in the out-patient clinic with oesophageal recordings is a safe, rapid and economic method of detecting arrhythmias (sinus node dysfunction or supraventricular tachycardia) in 60% of patients with syncope, especially if they have symptoms of palpitations.

[Does radiofrequency ablation of the bundle of Kent results in a lower risk of atrial fibrillation?]. / L'ablation par radiofréquence du faisceau de Kent fait-elle régresser le risque de fibrillation auriculaire?

Radiofrequency ablation of the Bundle of Kent is a common method of treating malignant forms of the Wolff-Parkinson-White syndrome and the paroxysmal junctional tachycardia which may complicate this condition. The aim of this study was to investigate the effects of ablation of a latent or patent Bundle of Kent on the prevention of atrial fibrillation. One hundred and thirty eight patients aged 15 to 81 years of age with one or more patent (Group I) (n = 96) or latent Bundles of Kent (Group II) (n = 42) underwent successful ablation of the Bundle of Kent. Five patients in Group I (5%) and 4 in Group II (9.5%) had spontaneous paroxysmal atrial fibrillation before ablation. During electrophysiological investigation, AF was induced in 7 patients, 2 of whom had spontaneous AF in Group I and 3 in Group II. During follow-up (3 +/- 1 years), 3 patients of Group I went on to develop AF: 2 of them had never had the arrhythmia before: 4 patients of Group II, including 2 with previous AF, went on to develop AF. The risk of spontaneous AF was correlated to older ages. The authors conclude that persistence of the risk of spontaneous AF after ablation of a Bundle of Kent should be investigated especially in patients over 45 years of age.

[Does radiofrequency ablation of the slow pathway prevent atrial fibrillation in cases of re-entrant intranodal junctional tachycardia?]. / L'ablation de la voie lente par radiofréquence dans les tachycardies jonctionnelles par réentrée intranodale prévient-elle le développement d'une fibrillation auriculaire?

The aim of this study was to assess the effects of ablation of the slow pathway on the eventual occurrence of atrial fibrillation (AF) in cases of intranodal junctional tachycardia (INJT). Two hundred and fifty seven patients were admitted for recurrent paroxysmal junctional tachycardia. The ages ranged from 15 to 87 years (average 54 +/- 16 years). Tachycardia was induced in all patients and the mechanism shown to be INJT in 215 patients. Twelve of these (6%) also had spontaneous paroxysmal AF. It was possible to induce INJT and AF in 23 patients during electrophysiological study (11%): of these patients, 4 had a history of AF associated with INJT. Radiofrequency ablation of the slow pathway was successfully carried out. Patients were followed up for 1 to 6 years (average 3 +/- 2 years). None were prescribed antiarrhythmic drugs. The results showed that of the 12 patients with spontaneous AF before ablation, 8 had recurrence of paroxysmal AF which required reintroduction of an antiarrhythmic treatment and a ninth patient is currently in chronic atrial fibrillation. All but one of the patients were over 65 years of age. The AF recurred 1 month to 4 years after ablation. Of the 19 patients without previous AF but with inducible AF, 2 developed spontaneous paroxysmal AF. Of the patients without previous AF and without inducible AF, 4 aged over 65 went on to develop paroxysmal AF. The authors conclude that radiofrequency ablation of the slow pathway of patients with INJT does not seem to prevent future development of AF in elderly subjects.

Influence of age on the potential risk of sudden death in asymptomatic Wolff-Parkinson-White syndrome.

Sudden death might be the first event in patients with asymptomatic WPW. The purpose of the study was to know if the age of the patient modifies the electrophysiological characteristics of asymptomatic WPW. Transesophageal stimulation was performed on 92 asymptomatic WPW patients from the following age groups: 10-69 years (n = 14), 20-29 years (n = 33), 30-39 years (n = 15), 40-49 years (n = 17), and 50-69 years (n = 13). The procedure consisted of atrial pacing up to the second AV block, programmed atrial stimulation using one and two extrastimuli delivered on two driven rhythms in the control state, and after infusion of isoproterenol. In thefive age groups, paroxysmal junctional tachycardia occurred, respectively, in 1 (7%), 1 (3%), 2 (13%), 2 (12%) patients, and not at all in the oldest group. AF > 1 minute occurred, respectively, in 3 (21%), 9 (27%), 5 (33%), 3 (18%), and 4 (31%) patients. The dangerous form of WPW (rapid conduction in the Kent bundle > 240/min in the control state or > 300/min after isoproterenol + AF induction) occurred, respectively, in 3 (21%), 9 (27%), 4 (27%), 1 (6%), and 3 (23%) patients. In conclusion, electrophysiological data of asymptomatic WPW are not modified by age of the patient. Elderly patients remain at risk of a dangerous form of WPW; systematic evaluation of WPWis recommended in patients with an active life independent of age.