[Induction of supraventricular tachycardia (paroxysmal junctional tachycardia and atrial tachycardia) by esophageal stimulation]

Transesophageal stimulation is tending to replace endocavitary electrophysiological studies in the investigation and treatment of supraventricular tachyarrhythmias. The aim of this study was to determine the sensitivity of this technique in the evaluation of paroxysmal junctional tachycardia (PJT) and atrial tachycardia (AT). Fifty-eight patients with these arrhythmias (PJT, n = 23; AT, n = 35) were investigated under basal conditions and then during Isoproterenol infusions with a protocol using incremental atrial stimulation and programmed atrial stimulation delivering one and two extra-stimuli on two paced rhythms (400-600 ms). It was possible to induce the arrhythmia in the 23 patients with PJT either under basal conditions (n = 16) or during Isoproterenol (n = 7). A reentrant mechanism was suggested in 22 patients by the following findings: position of the auriculogramme with respect to the ventriculogramme, presence or absence of a delaying branch block, situation and morphology of the P wave in lead V1 compared with atrial activation recorded by the esophageal catheter. Atrial tachycardia was induced in 26 patients (74 per cent), 19 under basal conditions, 6 with Isoproterenol and once after carotid sinus massage. As a conclusion, we can say that the sensitivity of transesophageal stimulation is the same as for endocavitary stimulation.

[Electrophysiologic effects of enoximone]

Most inotropic agents risk aggravating atrial and ventricular hyperexcitability associated with cardiac failure by their catecholergic-like effects. The aim of this study was to evaluate the electrophysiological effects of a powerful inotropic agent, enoximone, and to determine whether it had any arrhythmogenic effects. Endocavitary electrophysiological studies of conduction, induction of supraventricular tachycardia (SVT) by programmed atrial stimulation up to two extrastimuli and induction of ventricular tachycardia by programmed ventricular stimulation using up to 3 extrastimuli were undertaken before and 15 minutes after an injection of 1 mg/kg of enoximone in 10 minutes followed by an infusion of 0.75 mg/kg over 20 minutes. The studies were undertaken in 14 patients with severe cardiac disease (average ejection fraction: 26%): all had complex ventricular arrhythmias on Holter monitoring but only 7 had inducible sustained VT less than 270/mn under basal conditions. The following effects were observed with enoximone: significant shortening of all parameters of conduction; no aggravation of supraventricular excitability; no significant inducible ventricular arrhythmias in subjects without inducible sustained VT under basal conditions; facilitation of induction and acceleration of VT induced in 6 of the 7 patients with inducible sustained VT under basal conditions (VT cycle shortening from 307 +/- 13 to 240 +/- 34 ms). In conclusion, enoximone has no supraventricular arrhythmogenic effects and does not facilitate the induction of ventricular arrhythmias in subjects without inducible sustained VT under basal conditions. However, it can accelerate the VT rhythm in patients who have inducible sustained VT under basal conditions.

[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.

[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.

[Outcome of 195 patients with Wolff-Parkinson-White syndrome]

Between 1974 and 1984, 207 patients with Wolff-Parkinson-White syndrome (WPW) were admitted to our hospital department; 195 of them were followed up for periods ranging from 1 to 12 years (6 years in children, 3 years and 9 months in adults on average); 160 had undergone electrophysiological exploration. Fifty-seven patients were less than 16 years old: 7 died, including 6 with associated congenital heart disease; an asymptomatic 12-year old girl died suddenly while taking part in a sporting event. The signs of WPW disappeared in 5 out of 10 children under 1 year of age. One hundred and thirty-eight patients were older than 15: 15 of them died, but only 3 deaths were related to WPW: one was consecutive to surgery for WPW and one to fulguration; the third patient died of WPW tachyarrhythmia; the refractory period of his Kent's bundle was short, but his compliance with treatment was irregular. We found no correlation between changes in functional symptoms and Kent's bundle refractory period values; paradoxically, the frequency of attacks and resistance to treatment was higher in cases with long refractory period. On the whole, this series confirms that WPW usually is a benign disease. However, the risk of sudden death, of which it offers an example, indicates that all patients with WPW should be evaluated with at least an exercise test and, depending on its results or on the socio-professional context, an electrophysiological exploration.

[Ablation of the bundle of His through a patent foramen ovale, by approach from the left side]

The authors report the case of a 60-year-old male patient in whom resection of the bundle of His via a right-sided approach to treat permanent very rapid atrial fibrillation was attempted, but failed. The bundle of His tissue was resected very easily on the left side due to the presence of a patent foramen ovale, which also avoided the risks of the left catheterism in this patient.

[Complete atrioventricular block, a possible complication of radiofrequency ablation of reciprocating nodal tachycardia]

Radiofrequency ablation of the slow pathway of the reentry circuit is the usual radical treatment of nodal tachycardia. It is, however, possible to create atrioventricular conduction defects, the significance of which is not known. The aim on this study was to report the history of these conduction defects created during ablation of the slow pathway of the intranodal reentry circuit. Four cases were observed in a series of 27 patients. In one female patient, complete atrioventricular block was observed for 5 minutes before conduction returned to normal followed by recurrence of the tachycardias. Three other women developed complete atrioventricular block one to four days after the ablation. The block regressed after a maximum delay of 7 days. Six months to one year after the procedure, these three patients remain free of tachycardia and have only first degree atrioventricular block on the surface ECG. These patients were not implanted with a pacemaker. The authors conclude that complete atrioventricular block after ablation of the slow pathway may be treated conservatively, providing it is well tolerated. It normally regresses within few days.

[Outcome of Doppler parameters of left ventricular systolic function during atrial stimulation as a function of coronary disease]

The authors studied the effects of transoesophageal atrial pacing on Doppler parameters derived from flow in the left ventricular out flow tract (maximal velocity (V max), velocity-time integral (VTI), mean acceleration of aortic flow (Acc), acceleration force (AF) of the left ventricle). These parameters were recorded in patients with normal left ventricular wall motion at rest, with and without coronary disease. Eight patients had angiographically normal coronary arteries (Group 1) and 21 had coronary disease (Group 2) including 10 with an isolated stenosis of the left anterior descending artery (Group 2a) and 11 with multivessel disease (Group 2b). The heart rate was increased by increments of 20 beats per minute from 90 to 130 each minute. In coronary patients, atrial pacing resulted in a fall in V max from 0.99 +/- 0.15 to 0.90 +/- 0.12 m/s, p < 0.0005 and in AF from 23.1 +/- 6.3 to 19.6 +/- 4.8 Kdynes, p < 0.0005, whereas the Acc remained stable (13.51 +/- 3.27 and 13.53 +/- 2.47 m/s/s, NS). Conversely, V max (1.04 +/- 0.11 and 1.04 +/- 0.11, NS) and AF (25.2 +/- 5.7 and 26.3 +/- 6.7, NS) were unchanged in normal controls and the Acc improved from 13.87 +/- 3.61 to 17.04 +/- 3.49, (p < 0.05). The VTI fell significantly in both groups. The percentage variations of V max, Acc and AF were significantly different in coronary patients compared with normal controls. There were no differences between the two coronary subgroups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Influence of anti-arrhythmia agents on heart rate variability]

Since analysis of heart rate variability (HRV) is able to identify subjects at risk of sudden death and as antiarrhythmics can interfere with this prognosis, the objective of this study was to determine whether antiarrhythmics (AA) modified the HRV measured on a 24-hour Holter recording and after rapid ventricular stimulation and whether the initial HRV and its possible modification during treatment with AA were correlated with the results of AA treatment in patients with ventricular tachycardia (sustained VT). The HRV was studied in 50 patients with heart disease and spontaneous sustained VT, reproduced by programmed ventricular stimulation. This analysis was performed at baseline with antiarrhythmic treatment consisting of low-dose beta-blocker and quinidines in 26 patients (group I) or amiodarone in 24 patients (group II). Treatment was effective (i.e. prevented induction of VT) in 9 patients in group I (group la) and 5 patients in group II (group IIa). Treatment was ineffective in the other 17 patients of group I (group Ib) and 19 patients of group II (group IIb). The initial HRV was similar in the patients of groups Ia and Ib or groups IIa and IIb. Temporal analysis did not reveal any significant variation of HRV during AA treatment. In contrast, spectral analysis of HRV and the HRV observed during ventricular stimulation demonstrated a significant reduction of this parameter (p < 0.05 for groups I and II combined).

IN CONCLUSION

the initial HRV is not predictive of the results of treatment. Quinidines and amiodarone tend to decrease HRV regardless of the effect of the AA on the prevention of VT.

[Does radiofrequency ablation of the slow pathway prevent atrial fibrillation in cases of re-entrant intranodal junctional tachycardia?]

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.

[Prolongation of the averaged QRS complex. A simple prognostic factor in patients with post-infarction bundle branch block and a history of syncope]

Patients with a history of myocardial infarction and complete bundle branch block with syncopal episodes have a high risk of sudden death: the identification of the cause of the syncope is therefore essential. The aim of the study was to assess the diagnostic value of non-invasive techniques used in the investigations of syncope: 24 hour Holter recording, high amplification ECG and measurement of left ventricular ejection fraction. The results of these investigations were compared with those of complete electrophysiological investigation evaluating atrioventricular conduction and the inducibility of tachycardia. The patient population was 134 patients, 83 with right bundle branch block and 51 with left bundle branch block. Ninety one patients had inducible sustained ventricular tachycardia and 24 had atrioventricular conduction defects: of these, 14 also had ventricular tachycardia. During follow-up, there were 12 sudden deaths and 13 deaths from cardiac failure. Uni- and multivariate analysis showed induction of ventricular tachycardia to be a significant risk factor for global mortality and sudden death but prolongation of the averaged QRS complex (> 165 msec) was also an independent risk factor of global cardiac mortality. The authors conclude that simple prolongation of the averaged QRS duration > 160 ms in patients with right bundle branch block and > 170 ms in patients with left bundle branch block after myocardial infarction and syncope is a significant poor prognostic factor. However, this sign is not predictive of sudden death.

[Characteristics and causes of death in 283 patients with implanted defibrillators]

The implantable automatic defibrillator has proved its superiority over pharmacological treatments for preventing mortality by serious ventricular arrhythmia. We studied the cause of death in a population of 283 consecutive patients implanted between February 1988 and December 2000 (age at implantation: 58 +/- 14.7 years; extremes: 15-78 years, 45 females, ejection fraction: 0.39 +/- 0.15) and followed up over a median of 25 months (extremes = 1 day-163 months).

RESULTS

At the end of follow up, 55 patients had died (average age: 62.7 +/- 12.6 years, extremes: 15-79 years, 7 females). All except 2 had a cardiopathy: ischaemic cardiopathy (n = 38, 36 IDDM), dilated cardiomyopathy (n = 14), arrhythmogenic dysplasia of the right ventricle (n = 1). The median interval between implantation and death was 35 months (extremes = 1 day-137 months). The causes of death were the following: cardiac insufficiency (n = 24), refractory arrhythmias (n = 13), other cardiac causes (n = 8), extra-cardiac pathologies (n = 10). The deceased patients had presented an average of 86.6 +/- 23.4 ventricular arrhythmias (extremes = 0-1309) but 18 of them (33%) did not present any during follow up.

CONCLUSIONS

Cardiac insufficiency is the prime cause of death in refractory arrhythmias; on patient in 4 dies from ventricular arrhythmia, despite the defibrillator and one deceased patient in 3 had no arrhythmia during follow up.

[Syncope in patients with normal EKG and without cardiac disease: value of ambulatory esophageal electrophysiology in determining etiology]

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.

[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.

[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.