Prevalence, causes of reappearance of symptoms or preexcitation syndrome after ablation of accessory pathway and management

AIM

The purpose of the study was to look for the prevalence, significance and management of preexcitation syndrome (PS) or symptoms reappearance after accessory pathway (AP) ablation. AP ablation actually is the first treatment of PS.

METHODS

Successful AP ablation was performed in 261 patients; reappearance of symptoms or PS on ECG occurred in 47 patients (18%) from 20minutes to several years. Their data were compared with remaining patients.

RESULTS

Recurrences were more frequent in patients with spontaneous malignant form (34 vs. 21%), in congenital heart disease (4.2 vs. 0%) (P<0.002), in case of complication (11 vs. 2%) (P<0.007) and of a longer duration of applications (304±209 vs. 188±182sec) (P<0.019). Forty percent of patients had the same symptoms and electrophysiological data as before ablation. Twenty-four percent had an improvement of symptoms and/or electrophysiological data. However, 3 initially asymptomatic patients became symptomatic after ablation. Twenty-six percent had another AP or another rhythm disorder. We recommend transesophageal electrophysiological study for the control because only 40% of patients required second ablation.

CONCLUSIONS

Reappearance of symptoms or a PS on ECG after AP ablation was not rare (18%) and was inconsistently associated with the reappearance of all initial AP electrophysiological properties. Only 40% of patients required a second AP ablation. Another arrhythmia was possible. Non-invasive second evaluation should be preferred. However, asymptomatic patients before ablation could become symptomatic.

[Accessory pathway ablation in children: indications and results]

INTRODUCTION

Radiofrequency ablation of accessory pathways (AP) has become a first-line treatment, except in young children where the indications are discussed because of radiation risks and complications of catheterization. The purpose of the study was to evaluate the indications and results of radiofrequency AP ablation in children and teenagers.

METHODS

Electrophysiological study (EPS) was performed in 145 patients aged from 5 to 18 years (13.5±3) with a preexcitation syndrome (PS).

RESULTS

AP ablation was indicated in 66 children (group 1); others represent the group I. Group I was older and less frequently asymptomatic. All children with a spontaneous malignant form had an ablation. Group 1 has a faster conduction through the AP than group 2. The induction of reentrant tachycardia (RT), atrial fibrillation and the presence of a malignant form is more common in group 1. Failures or reappearances of WPW after ablation were frequent (20, 26%) related to a younger age (15±3 vs 17±4) (<0.05). In group 2, one 18-year-old teenager with untreated RT died before ablation. Asymptomatic children are well with disappearance of PS in two. Medically treated symptomatic children are well.

CONCLUSION

If spontaneous malignant forms, symptoms with drugs or practice of competitive sport are indications of AP ablation, it is recommended to wait for adolescence in other children.

Pharmacological testing in the diagnosis of arrhythmias

Pharmacological testing has several indications in the diagnosis of arrhythmia. It is used for the diagnosis of bradycardia-related syncope either during non invasive tests as adenosine triphosphate (ATP) for the diagnosis of vasovagal syncope, but also for the diagnosis of sick sinus syndrome or isoproterenol infusion during the head up tilt test to induce a vasovagal syncope or during electrophysiological study to look for infrahisian AV block or organic sick sinus syndrome after injection of Ajmaline or to know if sick sinus syndrome or suprahisian AV block are reversible after atropine and are vagal-related. It is used for the diagnosis of supraventricular and ventricular tachycardia; isoproterenol is largely used generally during electrophysiological study. The infusion of isoproterenol is required in exercise-related arrhythmias, in arrhythmogenic right ventricular cardiomyopathy, in idiopathic ventricular tachycardia and in idiopathic dilated cardiomyopathy. ATP can be used to induce a vagal-related atrial fibrillation and may help to differentiate a reentry through accessory pathway or AV nodal re-entrant tachycardia. It is used for the detection and the evaluation of prognosis of some diseases at risk of sudden death. Isoproterenol infusion is required in the preexcitation syndrome to look for the shortening of accessory refractory period. Ajmaline or flecaïnide injection is mandatory in the family of a patient with a Brugada syndrome to detect the disease.

[Which therapy for which patient? In daily practice]

Although the important progress in the curative treatment of atrial fibrillation, the indications of the regularisation of the first episode and of the preventive treatment remain difficult. Without real proofs on the interest of maintain in sinus rhythm, the indications depend on the age of the patient, the clinical tolerance and the objective impact on left ventricular ejection fraction.

The management of arrhythmic sincope

Arrhythmic syncope explains 5% to 20% of the causes of syncope and its incidence increases with age. In patients with arrhythmic syncope, a poor prognosis can be expected if syncope is misdiagnosed, particularly when arrhythmias occur in a patient with advanced heart disease. Arrhythmic causes are due either to bradycardia (diagnosed by surface electrocardiography, 24-hour Holter monitoring and electrophysiologic study in patients with bundle-branch block) or to supraventricular or ventricular tachycardia (diagnosed by electrophysiologic study and/or long-term event recording). Arrhythmic syncope can be easily prevented with antiarrhythmic drugs or, more frequently, with non-medical treatments such as radiofrequency ablation of tachycardia, and pacemaker or defibrillator implantation.

[Comparison of patients with paroxysmal junctional tachycardia and syncope with those without syncope]

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.

Incomplete bundle-branch block and ST-segment elevation: syndrome associated with sustained monomorphic ventricular tachycardia in patients with apparently normal heart

This paper reports on three cases of patients with an apparently normal heart admitted for sustained monomorphic ventricular tachycardia. The only abnormal finding showed in the electrocardiogram (ECG) in sinus rhythm that exhibited an entity associated with incomplete right bundle-branch block and persistent ST-segment elevation. The ECG entity was variable and disappeared transiently. Spontaneous ventricular tachycardia in one patient was inducible by programmed stimulation. There was no underlying heart disease. The origin of the ventricular tachycardia in one patient was located by pace mapping in the left ventricle at the left ventricular basal septum. The follow-up (from 6 months up to 6 years) demonstrated a good prognosis. This particular ECG entity associated with monomorphic ventricular tachycardia could have been missed because of the variations in the ECG in sinus rhythm and was associated with a favorable prognosis.

[Relationships between age and accessory pathway location in Wolff-Parkinson-White syndrome]

BACKGROUND

Radiofrequency ablation of atrioventricular accessory pathway (AP) which is currently used, remains associated with a risk of complete AV block in the case of anteroseptal (AS) location and its indication remains debatable. The purpose of the study was to evaluate the frequency of AS location in Wolff-Parkinson-White syndrome (WPW) and the clinical and electrophysiological data of these patients.

METHODS

Electrophysiologic study (EPS) was performed in 503 pts aged from six to 85 years (35+/-17), 297 men, 206 women, recruited for a patent WPW syndrome. The location of AP was determined on a 12 lead ECG during atrial pacing at maximal preexcitation according to classical criteria. The location was confirmed at EPS. Eleven pts were excluded because the location remained not clearly defined. EPS was indicated for suspected or documented tachycardias (n=264), syncope (n=68) or was systematic in asymptomatic patients (n=171).

RESULTS

AS AP location was identified in 34 patients aged eight to 48 years (7%). Their mean age was younger than the age of remaining population (25+/-13 versus 36+/-17, p<0.001). According to the age, the prevalence of AS location was significantly higher in children and adolescents (14%) than after 40 years (3%) (p<0.01). There was no AS location among 108 patients aged more than 50 years. The maximal rate conducted over AP was lower in patients with AS location than in other locations either in control state (174+/-60 per minute versus 197+/-63 per minute) (p<0.01) or after isoproterenol (206+/-71 versus 248+/-69) (p<0.01). The number of induced reciprocating tachycardia (47% versus 57.5%), atrial fibrillation (15% versus 21%) and malign forms (12% versus 17%) did not differ significantly in patients with AS location and in other patients. Anterograde conduction disappeared spontaneously in three of six patients followed 8+/-1.5 years, and significantly increased in two other patients.

CONCLUSIONS

AS AP location in WPW syndrome was more frequent in children than in adults. The maximal rate conducted over the AP was lower than in other locations. The incidence decreased after 40 years. AS AP location was never noted after 50 years in our population. This disappearance with age should be taken into account for the indications of AS AP ablation.

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.

[Bi-tachycardia and ischemic cardiopathy (following myocardial infarction)]

OBJECTIVE

The association of supraventricular tachycardia (SVT) and ventricular tachycardia (VT) is not common. The aim of this study was to evaluate its incidence and possible predisposing factors in patients with a history of myocardial infarction (MI), in order to correct them.

METHODS

Out of 359 patients consecutively recruited for spontaneous VT occurring at least one month after the acute phase of an MI, 33 were noted to have a possible association of SVT with VT. These patients underwent the following investigations: Holter recording, left ventricular ejection fraction (LVEF) measurement, and electrophysiological studies including programmed atrial and ventricular pacing.

RESULTS

The LEVF was 37.5+/-11%. An SVT was induced in 21 patients and a VT in 31 patients. Following investigation, the presumed factor predisposing to the two tachycardias was considered to be initiation of an SVT associated with rapid nodal conduction to the ventricle (Wenckebach point 210+/-23/mn) in 12 patients, branch to branch re-entry in 4 patients, reversible rhythmic dilated cardiomyopathy in 4 patients, an ischemic factor in 8 patients, post-operative period in 1 subject, infundibular VT in 1 subject, and an undetermined mechanism in 3 patients. The specific treatment of each of the identified etiologies usually prevented the recurrence of VT with the exception of one patient who had further VT during defibrillator recording, independent of any SVT.

CONCLUSION

The association of SVT with VT is rare because it was only noted in 9% of subjects who presented with spontaneous VT following myocardial infarction; This incidence is debatable, and could be an underestimate due to the fact that diagnosis is difficult. Several presumed predisposing factors are implicated and should be actively sought.

[Dilated cardiomyopathy and syncope: management]

Syncope occurring in patients with primary dilated cardiac disease has several causes: ventricular tachycardia (VT), a major severe cause of this diagnosis, occurring however only in one third of cases. The other causes are supraventricular tachycardia, bradycardia and vagal hyperactivity. The management depends on the etiology of syncope in one hand and the severity of the cardiac disease and other comorbidities in the other hand. In 2007, a patient with life expectancy exceeding one year, without irreducible heart failure but with a known and stable altered left ventricular ejection fraction (LVEF)<30%, will probably benefit of non-drug technology for the treatment of syncope (defibrillator with or without resynchronization), possibly in association with the treatment of another identified etiology, such as ablation or anti-arrhythmic treatment of a supraventricular tachycardia. In a patient with LVEF>30%, the electrophysiology exploration remains the most reliable recommended investigation for identifying the cause of syncope prior to discuss the implantation of a portable Holter device, indicated when the electrophysiology study is negative and syncope repeating.

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.

[Significance of permanent atrial fibrillation in idiopathic dilated cardiomyopathy]

The significance of atrial fibrillation (AF) in idiopathic dilated cardiomyopathy (IDCM) remains discussed. The purpose of the study was to evaluate the clinical significance of permanent atrial fibrillation in patients with IDCM.

METHODS

Systematic noninvasive and invasive studies including Holter monitoring, measurement of left ventricular ejection fraction (LVEF), electrophysiological study and coronary angiography were performed in 323 patients with IDCM; all patients had a left ventricular ejection fraction (LVEF)<40%. The studies were indicated for spontaneous ventricular tachycardia (VT) in 69 patients, syncope in 103 patients and nonsustained VT on Holter monitoring in 151 asymptomatic patients. Sixty-five patients were in permanent AF (group I). Remaining patients were in sinus rhythm at the time of evaluation (group II). Programmed ventricular stimulation using up to 3 extrastimuli in control state and if necessary after isoproterenol was systematic. Patients were followed 3+/-2 years.

RESULTS

Mean age was significantly older in group I (61+/-8 years) than in group II (52+/-12) (P<0.01). Syncope (31 vs 36%), spontaneous sustained VT (18 vs 23%); mean LVEF (28+/-9% vs 29+/-9%), VT induction (25 vs 35%) were similar in both groups. During the follow-up, there were no statistical differences between groups I and II concerning each event: sudden death occurred in 13 patients, 1.5% of group I patients and 5% of group II patients (NS); a death related to heart failure occurred 22 patients, 5% of group I patients and 7% of group II patients (NS); heart transplantation was performed in 13 patients, 8% of group I patients and 3% of group II patients (NS).

CONCLUSIONS

An older age is the only significant clinical factor associated with the presence of a permanent atrial fibrillation in idiopathic dilated cardiomyopathy. The presence of permanent AF does not increase the induction of a sustained ventricular tachycardia and does not affect the general prognosis of IDCM.

[Cognitive impairment induced by digoxin intake in patients older than 65 years]

Cognitive impairment or clinical signs of dementia in an old patient who receives digoxin, should suggest a digitalis intoxication. Symptoms can be present although a normal digoxin serum concentration. It is recommended to stop the treatment to obtain a regression of dementia symptoms.

[Influence of age on the presumed cause of syncope in patients with the Wolff-Parkinson-White syndrome]

The aim of this study was to assess the causes of syncope in patients with the Wolff-Parkinson-White syndrome (WPW) and to determine whether the age of the patients was a significant factor. Forty-seven patients with a WPW, aged 11 to 72 years, underwent electrophysiological study by the oesophageal approach because of an unexplained syncope. Nineteen patients were under 20 years of age (16 +/- 3 years: group I) and 28 were over 20 years of age (40 +/- 13 years: group II). Junctional tachycardia was induced in 8 patients of group I (42%) and in 13 of group II (46%) (NS); atrial fibrillation was induced in 8 patients of group I (42%) and in 9 of group II (35%) (NS). A potentially malignant form of WPW was identified in 8 patients of group I (42%) and in 11 of group II (39%) (NS); Syncope was directly attributed to the WPW in 14 patients of group I (74%) and in 19 of group II (78%), either after identification of a serious form or induction of junctional tachycardia (6 patients of group I and 8 of group II). The rest of the syncopal episodes had various causes. There were no deaths. The authors conclude that oesophageal electrophysiological investigations enable rapid identification of a high incidence of tachycardias probably responsible for syncope in WPW. The causes of syncope and incidence of potentially severe forms of WPW were not significantly influenced by the age of the patients.

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.

[Prevalence of sudden cardiac death during sports activities]

Sudden death during sport is a rare and unexpected event. It essentially affects young males, and a cardiomyopathy that had not been diagnosed during medical examinations is present in the majority of cases. In young subjects, there is generally hypertrophic cardiomyopathy or arhythmogenic right ventricular dysplasia. This is revealed during sporting activity, and sudden death is often the first symptom of the disease. Competitive sport increases the relative risk of sudden death to 2.5 compared to the risk in a non-sporting subject. The prevalence of sudden death during competitive sport is poorly understood. From the rare studies available, it could be estimated at 2.3/100,000 athletes per year. In Europe, it essentially occurs during football matches. However, the prevalence of sudden death during so-called 'recreational' sports is not precisely known. It could be much higher because these activities involve a larger number of people, and take place without supervision and usually without a medical examination beforehand. The participants are older, and coronary pathology is usually implicated.

[Respective interest of two techniques of electrophysiological study in patient without heart disease]

Electrophysiologic study (EPS) frequently is required to assess the prognosis of asymptomatic Wolff-Parkinson-White syndrome (WPW) or to prove the nature of no documented tachycardia. EPS usually is performed by intracardiac route and hospitalization is required. Similar data are given by an EPS performed by oesophageal route during a consultation. The purpose of the study was to evaluate the cost of both techniques in France. Transesophageal EPS was performed during a consultation in 100 patients with asymptomatic WPW syndrome and 100 patients with no heart disease, complaining of no documented tachycardias with abrupt beginning and end, suggesting a paroxysmal junctional re-entrant tachycardia (PJRT). The cost of transesophageal study including isoproterenol infusion is 127.75 euros. The cost of intracardiac EPS is at least 1460 euros, cost of hospitalization during only one day.

RESULTS

In patients with WPW syndrome, 15 had a potentially malignant form with the induction of a tachycardia conducted through the accessory pathway at a high rate (> 240/min in control state, > 300/min with isoproterenol); radiofrequency catheter ablation was indicated in a second time. In the group with no documented tachycardia, PJRT was induced in 30 patients and indication of ablation was discussed. In other 155 patients with either a benign form of WPW syndrome or with a tachycardia unrelated to a PJRT, hospitalization was not required; in these patients, intracardiac study performed during one day of hospitalization would have costed 226,300 Euros. The cost for the esophageal EPS and a similar diagnosis was 19,801 Euros, with a save money of 206,499 Euros. In 45 patients in whom hospitalization was indicated in a second time to perform catheter ablation of the arrhythmia, the cost related to esophageal EPS was 5749 Euros. In the total group, considering the final diagnosis and the need of hospitalization in 45 patients, the save money related to the use of esophageal EPS was 206,499 E-5749 E = 200,750 euros.

CONCLUSIONS

We should take into account the cost studies, when various techniques could be used for a similar diagnosis. There are important differences in the cost of diagnostic methods and it is easy to decrease this cost.

[Association of Wolff-Parkinson-White syndrome with isolated non-compaction of the left ventricle: a case report]

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.

[Significance of isuprel infusion in unexplained syncope after myocardial infarction]

The prognosis for patients with complications and syncope following myocardial infarction depends on the left ventricular ejection fraction (LVEF) and the mechanism of the syncope. The aim of this study was to evaluate the results of an electrophysiological study (EPS) following isoproterenol infusion in patients with a negative EPS under basal conditions. The population included 60 patients, aged 60 +/- 12 years, 5 of whom had syncope on effort or with stress. The EPS included measurement of AV conduction, with programmed atrial and ventricular stimulation. It was repeated following infusion of 2 to 4 microg/kg of isoproterenol.

RESULTS

An arrhythmia was identified as preceding the syncope in 27 patients (45%): ventricular tachycardia (VT) n = 16, supraventricular tachycardia (n = 5), 2nd or 3rd degree AV block (n = 3), vaso-vagal reaction (n = 3): 3 subjects developed coronary ischaemia. The subjects with VT on Isuprel differed from those without VT, with a lower LVEF (34 +/- 8 vs 45 +/- 14%) (p < 0.05), a higher incidence of effort related syncope (4 vs 1) and a higher risk of cardiac death (6/16 vs 2/44) (p < 0.01). In conclusion, we recommend repeating the electrophysiogical test under Isuprel in patients with complications after MI and a negative EPS in the basal state whether or not they have exercise related syncope, which will reveal an arrhythmia in 45% of cases. Subjects with inducible VT are at high risk of cardiac death.

[Prevalence of supraventricular tachycardia and tachyarrhythmias in resuscitated cardiac arrest]

Supraventricular arrhythmias are considered to be benign when the ventricular rate is slowed and treated by anticoagulants. The aim of this study was to determine the possible influence of these arrhythmias in resuscitated cardiac arrest. Between 1980 and 2002, 151 patients were admitted after a cardiac arrest. Supraventricular arrhythrmias were identified as a possible cause of the cardiac arrest in 21 patients. They underwent echocardiography, exercise stress test, Holter ECG monitoring , coronary angiography and electrophysiological investigation. After these investigations, three patients had a malignant form of the Wolff-Parkinson-White syndrome, two were asymptomatic and, in the third patient, ventricular fibrillation was induced by treatment with diltiazem. In 8 patients, a rapid supraventricular arrhythmia was considered to be the cause of cardiac arrest by cardiogenic shock; 2 patients had hypertrophic cardiomyopathy, 5 had severe dilated cardiomyopathy which regressed in one patient. In ten patients, cardiac arrest due to ventricular tachycardia or fibrillation was provoked by a rapid (> 220 beats/min) supraventricular arrhythmia; two patients had no apparent underlying cardiac pathology. In the others, myocardial ischaemia or acute cardiac failure were considered to be the cause of the cardiac arrest. The authors conclude that rapid supraventricular arrhythmias may cause cardiac arrest either by cardiogenic shock or degenerescence to ventricular tachycardia or fibrillation. Usually, this event occurs in patients with severe cardiac disease but it may occur in subjects without cardiac disease or by an arrhythmia-induced cardiomyopathy.

[Feasibility and significance of a transoesophageal electrophysiological investigation in children and adolescents with Wolff-Parkinson-White syndrome]

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.

[Paroxysmal atrioventricular block due to anticholinesterase therapy]

The authors report a case of paroxysmal syncopal complete atrioventricular block due to anticholinesterase therapy occurring after the first administration. The block was reversible. It is therefore important to exclude this cause of atrioventricular block in the elderly in view of the increasing indications of this therapy.

[Causes and prognosis of syncope in patients with primary dilated cardiomyopathy]

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.

[Response to drug therapy of cardiac failure according to gender]

The general profile of women with cardiac failure differs from that of the male population, especially with respect to aetiology and prognosis. Women are often older, have preserved systolic function more often and a higher incidence of risk factors such as hypertension and diabetes. Moreover, global mortality is lower in women. From the therapeutic point of view, women with symptomatic left ventricular dysfunction probably benefit from ACE inhibitors but those with asymptomatic dysfunction have no reduction in mortality with this class of drugs. In addition, treatment with ACE inhibitors is usually interrupted in women because of a higher incidence of secondary effects. The poorer tolerance could be explained by the profile of women with cardiac failure. The large scale multicentre trials with betablockers included very few women. In MERIT-HF, in which there was a large number of women (23%), the female subgroup was the only one in which a benefit in mortality was not demonstrated. However, a retrospective analysis of the data of this subgroup plus a meta-analysis of all trials with betablockers does show improved mortality with this class of drugs in women. In a retrospective study of the DIG study, there seems to be a difference in the effects of digoxin between men and women; the prescription of digoxin is associated with a higher overall mortality in women. Finally, women seem to require diuretics more often than do men. There are many explanations for the differences observed in therapeutic responses between men and women. The role of sex hormones is often evoked, although it has never been clinically proved. The treatment of heart failure in women should take clinical and biological factors specific to women into account and may explain the relative inefficacy of certain forms of treatment.

Wide QRS complex tachycardia. Rapid method of prognostic evaluation

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?]

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.

[Risk factors for cardiac mortality in cases of syncope with previous history of myocardial infarction]

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.