Distinctive response of arrhythmogenic right ventricular disease to high dose isoproterenol

Arrhythmogenic right ventricular disease is a potential cause of ventricular arrhythmias. Diagnosis is important due to the risk of sudden death, particularly as first symptom. Diagnosis is based on the angiographic demonstration of abnormal right ventricular morphology and function, while the sensitivity of noninvasive tests is relatively low. Following a particular observation studied in 1984, we prospectively assessed the diagnostic value of high dose isoproterenol infusion in 44 patients with an angiographically determined arrhythmogenic right ventricle. A continuous infusion of isoproterenol (8-30 micrograms/min) was administered during a 3-minute period, regardless of the obtained heart rate. In a control group of 50 patients without structural heart disease, isoproterenol induced a monomorphic ventricular tachycardia salvo in only one patient (2%). In patients with an arrhythmogenic right ventricle, isoproterenol induced one or more ventricular tachycardia runs in 39/44 cases (88%): one triplet in three patients, several runs in 23 patients and a sustained ventricular tachycardia in 13 patients. Arrhythmia was polymorphous in 85% of cases, but left bundle branch block morphology was the predominant pattern. In conclusion, high dose isoproterenol is a highly sensitive test for the diagnosis of arrhythmogenic right ventricular disease.

Fulguration for AV nodal tachycardia: results in 42 patients with a mean follow-up of 23 months

This report describes a catheter ablation technique to treat atrioventricular nodal reentrant tachycardia while preserving anterograde conduction, and its application in 42 patients with drug-refractory repetitive episodes of tachycardia. One of these patients had common and reverse forms of tachycardia. Using atrial activation in the His-bundle lead as a reference, the optimal ablation site was selected by positioning an electrode catheter to obtain a synchronous or earlier atrial activation than the reference during tachycardia. At this site, His-bundle deflection was completely absent, or was present at a low amplitude (less than 0.1 mV). In the majority of patients, these criteria were found in the immediate vicinity of the site of proximal His-bundle recording (adjacent to the reference catheter). Shocks of 160 or 240 joules (J) were delivered at this site (mean +/- SD = 518 +/- 392 J/session) with a resulting preferential abolition of impairment of fast retrograde conduction. Anterograde conduction, though modified, was preserved in all patients, except for four (10%) patients who remained in complete heart block. Thirty patients (70%) remained free of arrhythmia without medication or pacemaker for a mean follow-up period of 23 +/- 13 (2-63) months. Six other patients (15%) were controlled with a previously ineffective medication.

[Interventional rhythmology]

Interventional cardiorhythmology was born with the invention of electrical catheter ablation of the common atrioventricular bundle of His as a palliative treatment of supraventricular arrhythmias refractory to medicinal treatment. This method is now used as a curative treatment. In Wolff-Parkinson-White syndrome, all accessory pathways, whatever their location, can be destroyed with a very high success rate (96 p. 100) and very low morbidity and mortality rates. Reentrant nodal tachycardias can also be treated by catheter ablation with, however, a low risk of atrioventricular block which, for the moment, limits its indications. In intractable ventricular tachycardias, its indications will certainly be extended and its efficacy will increase since numerous recent studies have identified a limited, slow-conduction area (arrhythmogenic substrate) as being the real target for ablation. Other sources of energy are also used for the same purposes, including radiofrequency currents with results that are promising but vary according to the type of arrhythmia treated. Thus, interventional cardiorhythmology is progressively replacing surgery.

Catheter ablation of Mahaim fibers with preservation of atrioventricular nodal conduction

Three patients with refractory preexcited tachycardia implicating Mahaim fibers underwent attempted catheter ablation of the accessory pathway. In the absence of demonstrable retrograde conduction in Mahaim fibers, we located the accessory pathway ventricular insertion site using the criteria of concordance between paced and spontaneous QRS morphologies during pace-mapping and earliest onset of local electrogram relative to surface preexcited QRS. At this site, a QS-like pattern of unfiltered unipolar electrograms with steep downstroke was recorded. The optimal site appeared radiologically at the right ventricular anterior wall or the adjacent septum, 2-4 cm from the tricuspid anulus. Three to six 160-J shocks were delivered at this site using an anterior chest wall plate as anode. After fulguration, conduction through the Mahaim tract was absent. A right bundle branch block persisted in two patients. All patients remained free of preexcited tachycardia during 12-16 months of follow-up. Postablation electrophysiological assessment showed no preexcitation in any patient. No reciprocating tachycardia was inducible, even during isoproterenol infusion. Atrioventricular nodal conduction parameters were unchanged from baseline study. Catheter ablation of Mahaim fibers is an effective alternative method for the treatment of tachycardias that include the accessory pathway in the circuit.

[Value of the isoprenaline test in arrhythmogenic heart diseases]

The sympathetic nervous system seems to play a major role in the genesis of ventricular arrhythmias. The authors studied this adrenergic factor prospectively by exercise stress testing and intravenous isoprenaline in 107 patients referred for evaluation of arrhythmias or symptoms thought to be due to arrhythmias: 30 patients had morphologically normal hearts (15 ventricular extrasystoles, 15 bursts of ventricular tachycardia); 55 patients had dilated cardiomyopathy and 22 had probable or proven arrhythmogenic right ventricular dysplasia. Exercise testing was carried out with 30 watt increments every 3 minutes. Ventricular tachycardia was induced in 6 patients with apparently normal hearts (17%), 13 patients with dilated cardiomyopathy (31%) and 7 patients with arrhythmogenic right ventricular dysplasia (40%). Isoprenaline was infused for 3 minutes at a dose of 8-12 g/min: ventricular tachycardia was induced in 7 patients with apparently normal hearts (24%) and 23 patients with dilated cardiomyopathy. In some patients presenting with syncope, an arrhythmogenic response to isoprenaline was the only abnormality detected by the study protocol. An arrhythmia was induced by isoprenaline in 17 of the 18 patients with confirmed right ventricular dysplasia (94%), 12 of whom had sustained mono or polymorphic ventricular tachycardia. Two of these patients did not have significant right ventricular wall motion abnormalities. Four asymptomatic subjects related to patients with right ventricular dysplasia underwent the isoprenaline test; bursts of ventricular tachycardia were recorded in 3 of them. Polymorphic ventricular tachycardia was specifically associated with cardiac disease. The maximum heart rate attained by exercise testing (148 +/- 19/min) was higher than that attained with isoprenaline (148 +/- 22/min).(ABSTRACT TRUNCATED AT 250 WORDS)

[Fulguration and pre-excitation syndrome. Results in 121 patients]

Ablation of accessory pathway (AP) of any location was performed either with a right or a left approach (patent foramen ovale, transpeptal or a retrograde transvalvular aortic catheterism in 121 patients. The best ablation site was localized: 1) by the recording of a potential likely with the Kent bundle activation; 2) the earliest site of retrograde atrial activation during orthodromic reciprocating tachycardia (80 +/- 35 ms); 3) first ventricular potentials recorded ahead or synchronous with the delta wave in standard leads; 4) disappearance of preexcitation due to the pressure of the catheter on the AP (8 patients); 5) good degree of pace-map concordance with the major preexcitation. Two 160 joules cathodic shocks in close succession induced the disappearance of preexcitation in 113 patients. No recurrence of arrhythmia occurred in 118 patients without any preventive treatment with a follow-up ranging from 2 to 49 months (10 +/- 8). No serious side effect were observed except three permanent complete AV block. However one of them occurred after an unsuccessful surgical attempt which obviously had damaged the AV junction. Fulguration is efficient in any location of AP and can be the first line treatment in patients at risk with the WPW either symptomatic or not. These results indicate that appropriate treatment of patient the Wolff-Parkinson-White syndrome could be reassessed.

[Wolf-Parkinson-White syndrome. Intensive physical activity: the value of fulguration]

In subjects with Wolff-Parkinson-White syndrome an intense physical activity or the practice of sports may not only trigger off cardiac arrhythmias but also worsen their consequences and become life-threatening. A full electrophysiological study, including measurement of the anterograde refractory period of the accessory pathway, induction of atrial fibrillation and study of the effects of isoprenaline, seems to be indispensable to detect those patients who are most at risk. When the risk of potentially serious arrhythmia appears to be confirmed, catheter ablation of the accessory pathway may be the ideal solution, as it may cure the disease without the sequelae inherent in surgery. The results obtained in 19 athletes or subjects with intense physical activity (19) successes without preventive anti-arrhythmic treatment and at the cost of a single case of asymptomatic atrioventricular block) suggest that the catheter ablation technique will greatly benefit such patients.

Closed-chest ablation of left lateral atrioventricular accessory pathways

Thirty patients with a left lateral accessory pathway and drug refractory tachycardia underwent attempted transcatheter ablation of the accessory pathway. Three had a concealed accessory pathway and 27 had the Wolff-Parkinson-White syndrome. A quadripolar electrode catheter was positioned within the coronary sinus in order to locate the earliest retrograde atrial activation during orthodromic reciprocating tachycardia. The appropriate bipole was used as the radiographic and electrophysiologic reference of the insertion of the accessory pathway. A catheter was then introduced into the left atrium, through a patent foramen ovale (six patients) or after transseptal catheterization (14 patients) according to Croft's technique, or using a retrograde transaortic approach (10 patients). The mitral annulus was mapped with the left atrial catheter in order to record a synchronous or earlier atrial deflection than reference during reciprocating tachycardia. VA' time at the preablation site was 82 +/- 12 ms. Two to seven 160 J cathodal shocks (650 +/- 205 J cumulative per patient) were delivered at this site in 38 sessions. No significant side-effects occurred except for one case of right coronary artery spasm leading to inferior wall infarction. Following fulguration, accessory pathway conduction was abolished in all patients but one with a second accessory pathway. During follow-up of 1-34 months, all patients but one were free of tachycardia: reciprocating tachycardia recurred in one patient, who had a concealed accessory pathway, on the third day. Accessory pathway conduction, assessed in 10 other patients 3-26 months after the procedure, was absent. Coronary arteriography performed in seven patients was normal.(ABSTRACT TRUNCATED AT 250 WORDS)

[Immediate complications of fulguration of ventricular tachycardia and accessory pathways. Analysis of 318 endocavitary shocks]

Abnormal events occurring immediately following electric stimulation were studied in 85 patients--mean age 38.5 years (14-78)--during the performance of 318 intracardiac shocks applied in 110 sessions. This electric stimulation was done for treatment of tachycardias related to an accessory pathway (series AP: 64 patients), or ventricular tachycardias (series VT: 21 patients). The number of shocks per session was 2.4 +/- 1.4 and 4.6 +/- 3, for the series AP and VT respectively, and the cumulative energy per session, was 405 +/- 221 J and 1,007 +/- 735 J. Only events occurring within the first 30 minutes following the shocks, were evaluated. In the series AP, the 64 patients received a total of 208 shocks in 86 sessions, and 68 abnormal events were observed (33%): 35 complete atrio-ventricular blocks, of more than 10 seconds (17%), 29 sinus pauses exceeding 3 seconds (14%) and able to stretch to 30 seconds, 3 ventricular fibrillations (1.4%) and 1 atrial fibrillation. In the series TV, 21 patients received 110 shocks in 24 sessions, and only 10 abnormal events occurred (9%): 2 transient episodes of electromechanical dissociation (1.8%), 3 uniform VT (2.7%), 1 complete atrio-ventricular block (10 min.), 1 cardiac pause (4 sec), 1 ventricular fibrillation, 1 isolated haemodynamic depression and 1 Prinzmetal syndrome. All these events were temporary, 5 ventricular arrhythmias in 6 were treated with a new intracardiac shock, and there were no deaths related to electric stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Closed-chest ablation of retrograde conduction in patients with atrioventricular nodal reentrant tachycardia

We applied a new technique of catheter ablation to treat atrioventricular nodal reentrant tachycardia and preserve anterograde conduction, performing this procedure in 21 patients with repetitive episodes of tachycardia refractory to antiarrhythmic drugs. Using atrial activation in the His-bundle lead as a reference, we selected the optimal site of ablation by positioning an electrode catheter so that atrial activation occurred simultaneously with or earlier than the reference activation during tachycardia. At this site, the His-bundle deflection was completely absent or was present only at a low amplitude (less than 0.1 mV). In the majority of patients, these criteria could be met by withdrawing the catheter 5 to 10 mm from the site of the His-bundle recording (adjacent to the reference catheter). Shocks of 160 or 240 J were delivered at this site (cumulative energy [mean +/- SD], 689 +/- 442 J). Treatment resulted in preferential abolition or impairment of retrograde nodal conduction. Anterograde conduction, although modified, was preserved in 19 patients; complete heart block persisted in 2 patients. Sixteen patients remained free of arrhythmia, without medication or implantation of a pacemaker, for a mean follow-up period of 14 +/- 8 months (range, 7 to 42). Tachycardia was not inducible in 14 patients in a follow-up electrophysiologic study performed 3.6 +/- 6 months after the procedure. We conclude that catheter ablation is an effective alternative for the treatment of atrioventricular nodal tachycardia in patients with drug-resistant tachycardia.

[Electrophysiologic study of syncope. Prediction of results]

In order to determine the factors predictive of dysrhythmia or disorders of conduction, 20 variables were analysed retrospectively in 201 patients who had undergone electrophysiological exploration. The electrophysiological abnormalities found to be significant were major sinus dysfunction (corrected post-stimulation atrial pause longer than 1 second), subnodal block (HV interval greater than 70 ms) or induction of sustained monomorphous ventricular tachycardia. The electrophysiological exploration gave abnormal results in 50 patients (25 per cent) with ventricular tachycardia in 36, subnodal block in 11 and sinus dysfunction in 5. Multivariate analysis brought out 4 independent variables that were predictive of electrophysiological study results. Presence of a cardiac disease (P less than 0.001), male sex (P less than 0.001), bundle branch block (P = 0.002) or injury consecutive to a syncope (P = 0.003) were associated with an abnormal exploration. The odd ratio of an abnormal electrophysiological exploration in the presence of a variable as compared with the reverse situation was 10, 6.25, 3.8 and 5 respectively. Postprandial syncopes were associated with a negative exploration (P = 0.06). Combining these variables and using a logistic regression model would provide an estimate of the probability of a positive or negative electrophysiological study. The selection of a high probability group would then indicate whether or not an electrophysiological study would be required.

[The stunned myocardium. A new pathological entity]

A 70 years old woman presented with clinical, electrical and haemodynamic evidence of myocardial infarction. The course of the disease was unusual in that enzyme levels were not increased and the electrocardiogram and ventricular kinetics returned to normal 25 days after the infarction. This syndrome was typical of electrical and mechanical myocardial stunning. The physiopathological theories behind this post-ischaemic transient myocardial dysfunction syndrome and its practical consequences are presented.

Fulguration of ventricular tachycardia using high cumulative energy: results in thirty-one patients with a mean follow-up of twenty-seven months

Catheter electrical ablation of ventricular tachycardia (VT) was attempted in 31 patients (57 +/- 15 years) who had refractory recurrent VT. Fifteen patients had coronary artery disease, seven had arrhythmogenic right ventricular dysplasia, four had cardiomyopathy and five had no structural heart disease. Ten patients were NYHA class III-IV. Ten patients experienced cardiac arrest or syncope during VT. Twenty-two patients had only one documented morphologic type of spontaneous VT. Whereas nine patients had more than one: the VT was incessant or daily in 17 patients. One to 16 shocks (mean 5.6) of 160 to 240 joules each (1162 +/- 1060 joules) were delivered to the endocardial exit site of VT--as identified by endocardial activation mapping (29 patients) and pacemapping (31 patients)--during one (22 patients) or more than one session (nine patients). Cumulative delivered energy was 840 +/- 558 joules for right ventricular VT (11 patients) and 1362 +/- 1240 joules for left ventricular VT (20 patients). Reversible side effects occurring immediately after shocks included: nonclinical VT (two patients), ventricular fibrillation (two patients), AV block (three patients). Mean CK-MB fraction 6 hours after shocks was 91 +/- 46 IU/1. An electrophysiology study performed 7 to 10 days later demonstrated that the original clinical VT was inducible in seven patients, nonclinical monomorphic VT was inducible in eight patients and no VT was inducible in 13 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Fulguration of accessory pathways in any location: report of seventy cases

Ablation of accessory pathways (AP) in any location was performed in 70 consecutive patients using either a right or a left approach. Left free wall pathways were approached via a patent foramen ovale (eight patients) or by transseptal catheter (eight patients). The best ablation site was localized by recording a potential most likely due to Kent bundle activation (33/70 patients), the earliest site of retrograde atrial activation during orthodromic reciprocating tachycardia, earliest ventricular potentials recorded before or synchronous with the delta wave in standard ECG leads, disappearance of preexcitation due to pressure of the catheter on the AP (eight patients), good degree of pacemap concordance with ventricular preexcitation. Two 160 joules cathodal shocks in close succession were delivered and the sequence repeated depending on the results. Preexcitation disappeared in 63 patients and there was no recurrence of arrhythmia in 68 patients without any antiarrhythmic therapy over a follow-up ranging from 1 to 42 months. No serious side effects were observed except for two patients who developed permanent complete AV block. However, one of them occurred after an unsuccessful surgical attempt which had damaged the AV junction. Fulguration is effective for APs in diverse locations. These results indicate that appropriate treatment of patient with the Wolff-Parkinson-White syndrome should be reassessed. At present, the therapy of arrhythmias related to the Wolff-Parkinson-White syndrome is no longer a question of either antiarrhythmic drugs or surgery. Fulguration, in our experience, is effective for abolishing accessory pathways in any location.

[Electrophysiologic effects of intravenous flecainide in intranodal junctional tachycardia in 30 patients]

The electrophysiological effects of flecainide acetate were studied in 30 patients (10 men, 20 women, mean age 48.3 +/- 18 years) suffering from sustained re-entrant intranodal tachycardia. A 2 mg/kg dose of flecainide administered over 10 minutes was given after the onset of sustained tachycardia within 3.8 +/- 2.3 min in 25 of the 30 patients; this was effected by a block in the retrograde leg of the circuit in 22 patients and by a block in the anterograde leg in 3 patients. In the remaining 5 patients the tachycardia was slowed down (367 +/- 27 ms vs 431 +/- 48 ms) chiefly by prolongation of the atrioventricular anterograde conduction. No significant side-effect was observed while the drug was being injected. Following treatment with flecainide, tachycardia was no longer inducible in 24 out of 30 patients (A) and it remained inducible in 6 patients (B, non-responders). The initial electrophysiological exploration revealed differences between these two groups in retrograde conduction: prolongation of the ventriculoatrial time during incremental ventricular stimulation (A: 41 +/- 32 ms vs B: 81 +/- 142 ms, p less than 0.05) and prolongation of the atrioventricular time above 100 ms (A: 2/24 patients, B: 3/6 patients, p less than 0.01). The following electrophysiological parameters were significantly (p less than 0.01) ,modified after intravenous flecainide: AH and HV conduction intervals, atrial refractory periods, anterograde and retrograde atrioventricular conduction. Complete retrograde block was observed in 12 patients of group A. Thus, in this study flecainide arrested a reciprocal intranodal rhythm in 25 out of 30 patients and prevented the reinduction of tachycardia in 24 of these.(ABSTRACT TRUNCATED AT 250 WORDS)

Catheter ablation of accessory pathways with a direct approach. Results in 35 patients

Thirty-five consecutive patients with an overt accessory pathway, all but two suffering from arrhythmia (atrial fibrillation, reciprocating tachycardia, or both), underwent attempted transcatheter ablation (fulguration) of their accessory pathway. Thirty-three patients had been treated with a mean of 2.3 +/- 1.4 antiarrhythmic drugs. A standard bipolar catheter was positioned on the internal surface of the right or left atrioventricular anulus with 1) a subclavian approach of the right cardiac cavities in 29 patients with right-sided accessory pathway (n = 27) or left posteroseptal accessory pathway (n = 2), 2) a patent foramen ovale in five patients (two with a left posterolateral accessory pathway and three with a left parietal accessory pathway), and a transseptal catheterism (one patient with a left parietal accessory pathway). Cathodic shocks (mean, 4.3 shocks/patient) with a mean cumulative energy of 690 J enabled the ablation (disappearance of both anterograde and retrograde conduction) of the accessory pathway in 32 patients with a follow-up ranging from 1 to 32 months (mean, 10 +/- 8 months). Two of the remaining three accessory pathways were impaired: one pathway became intermittent, the anterograde effective refractory period of the second pathway increased from 260 to 410 msec, and the third pathway was slightly impaired. This latter patient is the only one who still requires therapy, with a single antiarrhythmic drug. All others are free of arrhythmias and require no therapy. Not using coronary sinus catheterism inclusive of its os has led to only a few, benign side effects. Only one third-degree atrioventricular block occurred in a posteroseptal accessory pathway ablation. Three cases of patients with incessant reciprocating tachycardia involving a further successful ablation occurred at the beginning of our experience. The best area for ablation is, in our opinion, the recording site for the Kent-bundle activity (18 of 35 patients), but a meticulous mapping of the atrioventricular anulus during orthodromic reciprocating tachycardia makes ablation possible when the shortest ventriculoatrial time (V-A') can be recorded with reliability (mean, 85 +/- 18 msec). Such a procedure is an alternative to surgical ablation regardless of the location of the accessory pathway--not only posteroseptally.

[Predictive factors of the therapeutic result in the prevention of auricular fibrillation. Role of electrophysiological studies]

A population of 50 patients suffering from paroxysmal attacks of atrial fibrillation was studied prospectively to evaluate the prognostic value of 20 variables: 6 clinical variables: sex, age, cardiopathy, number of arrhythmic attacks, "vagal" triggering, failure of class IA antiarrhythmic agents; 3 echocardiographic variables: left ventricular diastolic diameter and percentage of fibre shortening, left atrial diameter; 6 basic electrophysiological data: threshold, refractory periods at 110 and 150/min, modalities of induction of a sustained arrhythmia; 4 results observed with an infusion of flecainide in doses of 2 mg/kg: arrest or persistence of the arrhythmia, whether or not it could be reinduced and value of refractory periods; doses of flecainide administered orally. With a mean +/- SD follow-up period of 7.7 +/- 7.3 months, preventive treatment with flecainide 233 +/- 7 mg failed in 16 patients (32 per cent) and succeeded in 34 patients (68 per cent). Analysis of Kaplan-Meier curves and use of Cox's multidimensional model showed that two electrophysiological data were of prognostic value: atrial effective refractory period, and non-inducibility of the arrhythmia after intravenous administration of flecainide. Thus, the probability of failure increases with the refractory period value and decreases with the non-inducibility of the arrhythmia.

[Treatment of refractory ventricular tachycardia using cumulative high-energy fulguration]

Intracardiac electrode catheter ablation of arrhythmogenic foci, using cumulative high energy, was attempted in 29 patients (mean age 57 +/- 15 years) presenting with ventricular tachycardia (VT) refractory to antiarrhythmic drugs. A heart disease, present in 25 patients, was responsible for severe heart failure in 10 of them; 13 patients had myocardial infarction, 7 had arrhythmogenic dysplasia of the right ventricle, 5 had cardiomyopathy (dilated in 4, hypertrophic in 1). The myocardium was apparently normal in 4 patients, 2 of whom had mitral valve prolapse. Morphologically, VT was single in 20 cases, double in 4 cases and more than triple in 5 cases; arrhythmia was continual or occurred several times a day in 17 cases. In one (20 patients) or several (9 patients) catheter ablation sessions, 1 to 16 cathodic shocks of 160 to 240 Joules (1.180 +/- 1.062 J) were delivered after mapping and focal stimulation without irreversible adverse reaction. The cumulative energy delivered was 840 +/- 558 J in the right ventricle (11 patients) and 1.390 +/- 1.244 J in the left ventricle (18 patients). During a 23.4 +/- 12 months follow-up period, 4 patients died (2 of heart failure, 1 of a hitherto undocumented VT, 1 suddenly of bradycardia-asystole). VT was regarded as being controlled in 23/27 patients, 15 of whom were not taking antiarrhythmic agents. The presystolic potential during VT was -5 + 5 ms in the 4 failure cases versus -41 + 29 ms in the successful cases (p less than 0.05). It is concluded that electrode catheter ablation is an effective curative treatment of VT.(ABSTRACT TRUNCATED AT 250 WORDS)

[Fulguration of foci of atrial tachycardia in the adult]

Fulguration of the site generator of arrhythmia was attempted in three 31, 33 and 55 year-old patients presenting ectopic atrial tachycardias resistant to various antiarrhythmic medications. Episodes of atrial fibrillation and flutter were also documented in two of them. Two patients had a surgically corrected congenital cardiopathy:interatrial communication or pulmonary stenosis. Mapping of the endocardial emergence point was carried out with electrodes placed 1 cm apart, demonstrating the high atrial origin of the tachycardia, near the right atrium. The auriculogram preceded the earliest possible ectopic P wave by 20 to 70 ms; its multiphasic and prolonged morphology, suggested a local intra-atrial conduction disorder in the three cases. Cathodic shocks were delivered at this site without complications with cumulative energies of 720 J, 480 J and 320 J, respectively. The fulguration was ineffective and revealed other arrhythmic sites in two patients. Only patient n1 has been asymptomatic since 24 months under a treatment with Sotalol 160 mg which had been previously ineffective.

[Contribution of specific potential monitoring in the expression of accessory pathways]

The electrocardiographic expression of preexcitation results from the electrophysiological behaviour of the 2 conduction pathways: the normal pathway and the accessory pathway (AP). Its interpretation can only be deductive since the electrical activities of these 2 pathways are not recorded simultaneously. The validation of a K potential likely to represent Kent's bundle activation is based on criteria of exclusion of other origins (atrium, His bundle, ventricle). The K potential could be obtained in 16 of 32 consecutive studies. In 2 cases the unusual behaviour of the AP could be reliably studied owing to recording of the K potential. In case n. 1 a 35 ms increment in conduction was reproducibly observed by atrial extrastimulation at the atrium-Kent's bundle interface. In case n. 2 preexcitation was expressed on ECG only when the atrial rate was 70 to 100/mn. With lower atrial rates conduction in the AP was impaired by a 1st degree block with an atrium-Kent's bundle delay of 100 ms. Atrial acceleration reduced this delay to 40 ms, showing that this improvement in conduction reflected an initial block on the AP in phase IV. With higher atrial rates a block was observed on the AP in phase III either as an abrupt rupture of the atrium-Kent's bundle conduction, or as a block following progressive increment of the Luciani-Wenckebach type. Injection of ATP 20 mg produced and anterograde block on the AP at the atrium-Kent's bundle interface. Retrograde conduction seemed to be lacking in the AP since atrial activity was completely dissociated from induced ventriculograms.(ABSTRACT TRUNCATED AT 250 WORDS)

[Echocardiographic study of the early repolarization syndrome. Demonstration of dynamic obstruction with isoprenaline. Apropos of 16 cases]

This study provides detailed information on the echocardiographic data obtained before and during an intravenous infusion of isoprenaline in a group of 16 patients under 50 years of age presenting with early repolarization syndrome and in a control group of 16 patients of the same age-group. The stereotyped echocardiographic features of early repolarization syndrome are described. They include: in the basal state, ventricular hyperkinesia, anterior motion of the mitral valve and reduction of the left ventricular outflow tract; these data were significant when compared with the control group; under isoprenaline, dynamic obstruction of the left ventricle. The authors discuss the electrical significance of the early repolarization syndrome, the relationship between that syndrome and the borderline forms of obstructive hypertrophic cardiomyopathy and the role of catecholamines in the pathogenesis of obstructive hypertrophic cardiomyopathy.

[Indications and prospects of cardiac fulguration]

Fulguration is a new technique of palliative treatment (ablation or alteration of the atrioventricular junction) of refractory supraventricular tachycardias. It can be too a curative treatment of arrhythmias unresponsive to medial therapy and not suitable for surgery or implantable defibrillator (ventricular tachycardias - refractory arrhythmias of the Wolff-Parkinson-White Syndrome and permanent or incessant form of reciprocating tachycardia). An original indication of this method is the ablation of the retrograde pathway alone in refractory intranodal reciprocating tachycardias. The results of these indications are herein analysed.

[Incidence of short-term arrhythmias after endocavitary fulguration]

The potential short-term arrhythmogenic role of catheter-mediated electrical ablation was studied in 61 patients of mean age 44 years (range 15-80 years) who underwent this procedure for Wolff-Parkinson-White syndrome (36 patients) or ventricular tachycardia (VT, 25 patients). Continuous ECG monitoring was pursued during the 24 hours that preceded and followed ablation. Only bursts of 3 consecutive beats or more were considered significant. Recordings were performed with either a Hewlet Packard 78720 A arrhythmia recorder or a Holter readout system (Oxford Medilog 2, Marquette). In 36 patients with an accessory conduction pathway the 160 J were delivered at the annulus fibrosus cordis. Post-ablation recordings showed: VT bursts in 16 patients (17%); the bursts disappeared in every case before 3 days; in 3 patients the electrogram at the site of ablation was predominantly ventricular (p less than 0.05); frequent or subintrant attacks of reciprocal orthodromic rhythm (RR); in 3 cases RR began on simple variations of heart rate; it reflected a loss of the anterograde conduction hidden in the accessory pathway and required a second ablation; in 1 case RR initiated by VT bursts revealed the presence of a second accessory pathway; atrial tachycardia bursts, spontaneously resolved, in 4 patients (11%). No atrial fibrillation of flutter was recorded. In patients with VT ablation was delivered in the right ventricle (160 J, 9 patients) or in the left ventricle (240 J, 16 patients). The effects of ablation could only be interpreted in 21 patients who underwent 25 ablations.(ABSTRACT TRUNCATED AT 250 WORDS)

[Oral flecainide in the treatment of refractory arrhythmias. Long-term follow-up of 98 patients]

Oral flecainide was administered to 98 patients with arrhythmias regarded as resistant to other antiarrhythmic agents: quinidines (82), propafenone (40), beta-blockers (30), amiodarone alone (38) or combined with a class I compound (19). Therapeutic effectiveness was assessed on clinical date, repeated Holter recordings (64 patients), exercise tests (8) and electrophysiological exploration (15). Mean follow-up was 11.7 +/- 11 months; the patients treated have now been followed up for 18.2 +/- 12 months (range: 7-58 months). Fifty-three patients had atrial arrhythmia (fibrillation or flutter in 45, atrial tachycardia in 8). Flecainide was effective in 26 patients (49%) and ineffective in 27 (51%). There was no significant difference in dosage between these 2 groups: 231 +/- 62 mg/day and 265 +/- 61 mg/day respectively. Paroxysms of re-entrant junctional tachycardia were controlled in 6 of the 8 cases observed. Eleven patients presented with Wolff-Parkinson-White syndrome: treatment was successful in the 3 patients with atrial fibrillation and in 8 of the 10 patients with orthodromic reciprocating rhythms. Among 30 patients with episodes of ventricular tachycardia, 9 (30%) responded to flecainide and 21 (70%) failed to respond. Flecainide reduced the repetitive forms by more than 90% in 7/15 patients and suppressed exercise-induced ventricular tachycardia in 2/8 patients. Fifteen out of 18 patients had ventricular tachycardia reproducible by programmed stimulation; under flecainide, the ventricular tachycardia spontaneously recurred in 4 cases, was provoked by stimulation in 5 other cases, was more easily inducible in 3 cases and was not inducible in a sustained manner in the last 3 cases.(ABSTRACT TRUNCATED AT 250 WORDS)