Catheter ablation of permanent junctional reciprocating tachycardia with radiofrequency current

OBJECTIVES

This study evaluated accessory pathway location, its relation to retrograde P wave polarity on the surface electrocardiogram and radiofrequency ablation efficacy and safety in a large group of patients with permanent junctional reciprocating tachycardia.

BACKGROUND

Permanent junctional reciprocating tachycardia is an uncommon form of reciprocating tachycardia, almost incessant from infancy and usually refractory to drug therapy. It is characterized by RP > PR interval and usually by negative P waves in leads II, III, aVF and V4 to V6. Retrograde conduction occurs through an accessory pathway with slow and decremental properties. Although this accessory pathway has been classically located in the posteroseptal zone, other locations have been recently reported.

METHODS

The study included 32 patients (20 men, 12 women, mean [+/- SD] age 29 +/- 15 years) with a diagnosis of permanent junctional reciprocating tachycardia confirmed at electrophysiologic study. Seven patients had depressed left ventricular function. Radiofrequency energy was applied at the site of the earliest retrograde atrial activation during tachycardia.

RESULTS

There were 33 accessory pathways. The site of the earliest retrograde atrial activation was posteroseptal in 25 patients (76%), midseptal in 4 (12%), right posterior in 1 (3%), right lateral in 1 (3%), left posterior in 1 (3%) and left lateral in 1 (3%). Thirty pathways were ablated with a right approach; in 11 patients with posteroseptal pathway the ablation was performed through the coronary sinus. Three pathways were ablated with a left approach. Positive retrograde P wave in lead I suggested that ablation could be performed from the right side; if negative, it did not exclude ablation from this approach. All the accessory pathways were successfully ablated, with a median of 3 and a mean of 5.6 +/- 5 radiofrequency applications of 70 +/- 26 s in duration. In two patients with the accessory pathway in the midseptal zone, a transient second- and third-degree atrioventricular block, respectively, was observed after ablation. At a mean follow-up of 18 +/- 12 months, 31 patients (97%) are asymptomatic without antiarrhythmic therapy (95% confidence interval [CI] 84% to 99%). Recurrences were observed in four patients (13%) (95% CI 4% to 29%), three of whom had the accessory pathway ablated successfully at a second session. All patients with depressed left ventricular function showed a marked improvement after successful ablation.

CONCLUSIONS

In our experience, most of the patients with permanent junctional reciprocating tachycardia had posteroseptal pathways; all these pathways were ablated from the right side. P wave configuration may be helpful in suggesting the approach to the site of ablation. Catheter ablation using radiofrequency energy is an effective therapy for permanent junctional reciprocating tachycardia.

Idiopathic verapamil-responsive left ventricular tachycardia: clinical characteristics and long-term follow-up of 33 patients

Long-term prognosis, pharmacological prophylaxis and transcatheter ablation in a large group of patients with idiopathic verapamil-responsive left ventricular tachycardia (IVRLVT) are reported in this study. Thirty-three patients with a mean age of 27 +/- 16 years at their first IVRLVT episode, were studied retrospectively. Ventricular tachycardia was of the right bundle branch block morphology in all cases, with left axis deviation in 29 and right axis deviation in five (one patient had the two morphologies). Mitral valve prolapse was present in four patients; no heart disease was found in the remaining 29. Ventricular tachycardia could be electrophysiologically induced in 90% of the patients; Holter monitoring showed only sporadic ventricular extrasystoles in 76%; late potentials were found in 33% of the cases. At the end of a follow-up of 5.7 +/- 4.7 years, no patient had died. Thirty-one patients (94%) received a mean of 2.5 +/- 1.2 drugs; beta-blockers were effective in 71% of the cases, verapamil in 25%, class 1 drugs in 22%, class 3 drugs in 18%. Two patients who never received prophylaxis and four in whom it was stopped, were controlled with verapamil in case of recurrence. Six patients underwent catheter ablation; two with DC shock in whom it was successful in one, and four with radiofrequency energy, with a total success rate. The good prognosis of IVRLVT has been confirmed in a long-term follow-up; a new finding is the high efficacy of beta-blockers for prophylaxis. Radiofrequency transcatheter ablation is an effective and safe therapy for patients with symptoms not controlled by drug treatment.

[Ventricular fibrillation in Wolff-Parkinson-White syndrome. Predictive factors]

The incidence of sudden death in the Wolff-Parkinson-White (WPW) syndrome is not well documented and probably underestimated. This retrospective study concerned 28 consecutive patients presenting with ventricular fibrillation either spontaneously (20) or during electrophysiological investigation (8) but whose characteristics allowed them to be assimilated into a single group. Their clinical and electrophysiological characteristics were compared with those of 60 consecutive patients with the WPW syndrome who had documented atrial fibrillation (and even reciprocating tachycardia) but never ventricular fibrillation. There were no significant differences between the two groups with respect to the following clinical parameters: sex, duration of symptoms, the type of tachycardia previously recorded, history of syncope and presence of underlying cardiac disease. With respect to the electrophysiological data, there were no differences in the point of anterograde block, the effective anterograde refractory period of the accessory pathway, the effective and functional refractory periods of the right atrium and atrial vulnerability. On the other hand, a significant difference was observed in the age of patients with ventricular fibrillation (29 +/- 13 years vs 36 +/- 12 years; p < 0.02), the prevalence of multiple accessory pathways (25% vs 7%; p < 0.04) with a dominant localisation in the postero-septal region (75% vs 47%, p < 0.026), preexcitation during exercise stress testing and under antiarrhythmic therapy (95% vs 68%, p < 0.037). The most discriminating parameter was the shorter RR interval during atrial fibrillation (172 +/- 23 ms vs 230 +/- 50 ms, p < 0.008). Multivariate analysis only showed one independent predictive factor: the minimum preexcited RR interval.(ABSTRACT TRUNCATED AT 250 WORDS)

Life-threatening pulmonary embolism with right-sided heart thrombus. Rapid recovery with recombinant tissue plasminogen activator

We report the case of a woman treated with urokinase for acute pulmonary embolism with a right-sided heart thrombus. She developed life-threatening acute cor pulmonale which dramatically improved within 4 h with recombinant tissue plasminogen activator (rtPA). We emphasize the clinical interest of rtPA for the treatment of life-threatening pulmonary embolism.

Catheter ablation of accessory pathways in children

The efficacy and safety of catheter ablation of accessory pathways (AP) was studied in 79 children (age, 4-16 years), using DC shocks (n = 25) or radiofrequency energy (n = 54). All patients had documented arrhythmias including ventricular fibrillation in four. Organic heart disease was present in four patients. AP locations were left lateral (n = 36), posteroseptal (n = 36), right lateral (n = 8), Mahaim fibres (n = 2) and right anteroseptal (n = 6). Seven patients had multiple AP. One patient had a preexcitation which appeared secondary to an atrio-infundibular connection (Fontan procedure). The ablation site of concealed or overt AP was identified by retrograde or anterograde conduction mapping, respectively. A mean of 2.6 +/- 1 cathodal shocks (80-160 J) was delivered to 25 patients over 29 sessions, resulting in initial AP ablation in all. Fulguration was uncomplicated in all except in one patient (4%) who developed a secondary complete AV block post-ablation. During a follow-up period of 30-69 months, intermittent preexcitation recurred in two asymptomatic patients, but no significant tachycardia was inducible at late electrophysiological study, including under isoproterenol infusion. Radiofrequency energy was applied to 54 patients during 62 sessions, using 20-40 watts for 30-60 s. AP ablation was initially achieved in all patients using a median of three impulses, without significant immediate side-effects. Two patients (4%) developed a short episode of blurred vision possibly due to a microembolism. After discharge, the follow-up period was 10 +/- 5 months (range 1 to 24). All patients but one (98%) were asymptomatic without any drug therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

[Ablation of junctional tachycardia by radiofrequency currents. Experience with 538 patients]

Junctional tachycardias may be related to intranodal reentry or to the existence of an accessory pathway. All are suitable for radical treatment by radiofrequency current applied either in the perinodal region or at the tricuspid or mitral atrioventricular rings respectively. 176 patients with intranodal reentry were treated by preferential modification of the rapid (8) or slow (167) anterograde pathway of the reentry circuit, with a 99% success rate (1 failure) and without significant complications, in particular atrioventricular block in the case of ablation of the slow pathway. 362 patients with one or more accessory pathways, patent or latent, were treated using the same type of energy. The ablation site was determined on the basis of indirect criteria and/or recording of the specific activity of the accessory pathway. The success rate here was 98%, once again without significant complications with the exception of those inherent to catheterisation procedures. Treatment duration time was 41 +/- 38 min in the treatment of intranodal reentry and 58 +/- 49 when one or more accessory pathways were responsible. X-ray exposure times were 14 +/- 14 min and 23 +/- 21 min respectively. Such results would justify the expectation of widened indications of the method.

Carcinoid heart disease: two cases of left heart involvement diagnosed by transthoracic and transoesophageal echocardiography

We report two observations of significant left heart involvement in patients with the carcinoid syndrome assessed by transthoracic and transoesophageal echocardiography. Echocardiographic lesions of this kind have only been reported twice. In the present cases, there was mitral involvement with mitral regurgitation in one case and a mitro-aortic involvement with mitral and aortic regurgitation in the other. The mechanism of left heart lesions is unclear since in both cases no right-to-left cardiac shunt was present, as attested by colour Doppler and saline contrast transoesophageal echocardiography. The location of the primary tumour was unknown in one case and ileal in the other; no pulmonary metastasis was detected. The use of transoesophageal echocardiography might make it possible to detect left-sided cardiac lesions more frequently since they were found in anatomical series, in 30% of patients with carcinoid syndrome.

[Attacks of junctional tachycardia: from arrest of crisis to radical cure]

Junctional tachycardias are among the most frequent or paroxysmal supraventricular tachycardias. They are due to a reentry mechanism and include the so-called nodal reentrant tachycardias as well as tachycardias which imply a patent or hidden accessory pathway. The prognosis of these tachycardias is usually benign, but it can be made unfavourable by repeated attacks or by the presence of an accessory pathway with short anterograde refractory period which exposes the patient to severe arrhythmia. Clinicians are now provided with a therapeutic armentarium that enables them to reduce easily any attack of junctional tachycardia, but also to prevent recurrences. The intracavitary ablation technique by application of radiofrequency currents ensures the radical cure of recurrent or threatening arrhythmias by suppressing the indispensable anatomical substrate of tachycardias.

[Nodal reentry tachycardia: short- and long-term effectiveness and safety of a selective ablation technique of the slow pathway]

BACKGROUND

Various ablation methods have been proposed in the last few years in order to find a radical solution for atrioventricular nodal reentrant tachycardia. The first techniques were surgical, followed by modulation of the fast pathway, causing a prolongation of the P-R interval, the latter involving a 2 to 10% atrioventricular block risk. To reduce this risk, slow pathway ablation was then suggested, with the objective of abolishing atrioventricular reentry. The aim of our study was to evaluate how frequently the recording of peculiar slow potentials was possible in patients with atrioventricular nodal reentrant tachycardia, and to assess short-and long-term efficacy of an ablation technique involving the use of these potentials as electrophysiologic markers.

METHODS

One hundred and eighty-eight patients with typical atrioventricular nodal reentrant tachycardia were studied (mean age 47 +/- 18 years). Radiofrequency ablation was guided by peculiar slow potential recordings; when this was not possible, fast pathway ablation, or slow pathway ablation guided only by anatomic markers, were performed.

RESULTS

Potentials with peculiar electrophysiologic characteristics were found during sinus rhythm in the median posterior region of the septum, anteriorly to the coronary-sinus ostium, in 92% of patients. These characteristics included: low amplitude; the fact that they occupy the first part of the interval between the atrial and ventricular electrogram; their amplitude diminishes and disappears with increased frequency of atrial stimulation and/or with atrial extrastimulus. Typical atrioventricular nodal reentry tachycardia was no longer inducible in any patient at the end of the procedure with a median of 2 radiofrequencies application per patient. No II or III degree atrioventricular block was caused when ablation was guided by slow potential recordings. During an attempt at fast pathway ablation a complete atrioventricular block was caused in 1 patient. One hundred and eighty-four patients remained asymptomatic during a follow-up of 2 to 24 months; no one showed either a modification of atrioventricular conduction if compared to that found at hospital discharge or proarrhythmic effects. Four patients had one atrioventricular nodal reentrant tachycardia recurrence and a second successful ablation was performed in 2 of these 4 patients.

CONCLUSIONS

Peculiar slow potentials, that can be used as electrophysiologic markers for slow pathway ablation, were recorded in the medio-posterior region of the septum in the majority of patients. The fact that this technique, using slow potential as an electrophysiologic marker, was successful in all patients, with very few recurrences and with no serious complications (no II or III degree atrioventricular block) makes it trustworthy and safe.

[Radiofrequency treatment of junctional tachycardia]

Atrioventricular nodal tachycardias due to intranodal reentry or to an accessory pathway are accessible to radical cure with radiofrequency currents applied either at the site of recording of characteristic slow potentials or at the tricuspid or mitral atrioventricular rings. One hundred and six patients with atrioventricular nodal reentry were treated by modification of the slow anterograde reentrant pathway with a 100% success rate and without any serious complications (especially atrioventricular block). One hundred and eighty six patients had one or more overt or latent accessory pathways and were treated by the same method. The ablation site was decided on indirect criteria and not by the recording of the specific activity of the accessory pathway. The success rate was 97%, also with no significant complications. The duration of the treatment was 41 +/- 22 min for the accessory pathways. The exposure time to ionising radiation was 14 +/- 14 min and 31 +/- 34 min respectively. These results suggest that the indications of radiofrequency current ablation could be extended.

Electrogram patterns predictive of successful radiofrequency catheter ablation of accessory pathways

We assessed anterograde conduction electrogram parameters at successful ablation sites according to accessory pathway (AP) location and compared them to the most favorable electrograms at unsuccessful sites. A median of three radiofrequency energy impulses was applied to ablate 97% of 136 APs versus four impulses to ablate 90% of 65 concealed APs. Electrograms at successful sites showed variable A/V ratio (0.04-7), and a QS pattern of unipolar ventricular wave in 90%. Electrograms were different in right versus left AP: AV time 29 +/- 7 versus 38 +/- 10; and timing of ventricular deflection: 17 +/- 9 versus 2 +/- 9 msec, respectively. Analysis in each patient of the mapping parameters at successful versus "most favorable" unsuccessful sites showed an improvement in at least one parameter in 55%, no apparent change in all parameter values in 30%, and even less favorable parameters in 15% of patients. In patients with manifest AP, overall comparison of electrograms at successful versus unsuccessful sites showed no difference in A/V ratio (1.3 +/- 1.5 vs 1.2 +/- 1.6), unipolar pattern distribution, and AV time (34 +/- 10 vs 35 +/- 9), but earlier bipolar main ventricular potential (-4 +/- 12 vs -1.5 +/- 10 msec) and unipolar intrinsic deflection timings (-5.2 +/- 11 vs -1.8 +/- 10 msec). In patients with concealed AP, a retrograde continuous electrical activity was recorded in 72% of successful versus 38% of unsuccessful sites (P = 0.03).

CONCLUSIONS

Electrogram characteristics at successful radiofrequency ablation are different in right and left manifest AP.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiofrequency catheter ablation of left lateral accessory pathways via the coronary sinus

BACKGROUND

The purpose of this study was to describe a new technique for catheter ablation of left lateral accessory pathways (APs) by radiofrequency energy applied at the epicardium through the coronary sinus wall using a unipolar configuration.

METHODS AND RESULTS

In an overall group of 212 patients with left lateral APs, multiple endocardial ablation attempts of the AP were unsuccessful in eight patients. The mean +/- SD cumulative duration of previous attempts was 12 +/- 9 hours, using DC shocks and/or radiofrequency energy applied both at the atrial and/or ventricular AP insertions. Epicardial AP insertion was determined by bipolar and unipolar unfiltered distal electrograms by scanning the coronary sinus with a steerable 6F or 7F catheter with a 4-mm distal electrode. The local atrial to ventricular electrogram amplitude ratio was 0.3-1.6. At the ablation site, the catheter tip was slightly deflected toward the annulus to increase both the ventricular component of electrograms and contact with the epicardium. In four patients, epicardial electrogram timings were earlier than endocardial ones. The AP was ablated in seven of the eight patients with 20-30 W applied for 10-60 seconds. No complications occurred except a marked nonspecific pain during radiofrequency energy application; however, the catheter remained adherent to the coronary sinus wall, and its withdrawal was performed during a new radiofrequency application to decrease the risk of coronary sinus rupture. After ablation, echocardiograms, coronary artery angiograms, and levophase coronary sinus angiograms showed no abnormality in all patients except two who had a probable mural thrombus in the coronary sinus. AP conduction remained abolished for 1-10 months of follow-up in seven patients.

CONCLUSIONS

Radiofrequency catheter ablation of left lateral APs can be achieved effectively and relatively safely via the mid or distal coronary sinus when endocardial approaches are unsuccessful.

[Complementary value of the isoprenaline test and high-amplification ECG in the diagnosis of arrhythmogenic dysplasia of the right ventricle]

Arrhythmogenic dysplasia of the right ventricle is a common cause of ventricular arrhythmia. It is important to reach a diagnosis, due to the risk of sudden death, particularly as this may be the first sign of the disease. Diagnosis is based on the angiographic demonstration of a morphological or structural abnormality of the right ventricle, and non-invasive tests are relatively insensitive. From a case investigated in 1984, the authors carried out a prospective determination of the diagnostic value of the isoprenaline test in 61 patients suffering from arrhythmogenic dysplasia of the right dysplasia confirmed by angiography. High concentrations (8-30 micrograms/min) of isoprenaline were continuously infused over a period of 3 minutes, regardless of the heart rate achieved. In a control group of 50 subjects with no myocardial disorder, isoprenaline induced monomorphic wave-burst arrhythmia in only one patient (2%). In the subjects affected by right ventricular arrhythmogenic dysplasia, isoprenaline induced one or more episodes of wave-burst ventricular arrhythmia in 52 patients (85%): one triplet in four patients, several episodes of wave-burst arrhythmia in 31 patients and prolonged ventricular tachycardia in 17 patients. Polymorphic arrhythmia occurred in 80% of cases, but left lag forms predominated. High-amplification ECG demonstrated late potentials in 66% of cases, i.e. in 80 and 62% of patients with and without prolonged VT respectively. The isoprenaline test or high-amplification ECG gave abnormal results in 58 of the 61 patients, with a cumulative sensitivity of 95 percent.

Elimination of atrioventricular nodal reentrant tachycardia using discrete slow potentials to guide application of radiofrequency energy

BACKGROUND

Ablation of the slow pathway has been performed to eliminate atrioventricular (AV) nodal reentrant tachycardia (AVNRT) either by a surgical approach or by using radiofrequency catheter technique guided by retrograde slow pathway activation mapping. From previous experience of midseptal and posteroseptal mapping, we were aware of the existence of peculiar slow potentials in most humans. Postulating their role in AVNRT, we studied these potentials and the effects of radiofrequency energy.

METHODS AND RESULTS

Sixty-four patients (mean age, 48 +/- 19 years) with the usual form of AVNRT were studied. Slow, low-amplitude potentials were recorded when using the anterograde AV conducting system. Slow potentials occupied all (giving a continuum of electrograms) or some of the time between the atrial and ventricular electrograms. Their most specific patterns were their progressive response to increasing atrial rates, which resulted in a dramatic decline in amplitude and slope, a corresponding increase in duration, and a separation from preceding atrial potentials until the disappearance of any consistent activity. Slow potentials were recorded along a vertical band at the mid or posterior part of the septum near the tricuspid annulus. Radiofrequency energy applied at the slow potential site resulted in interruption of induced tachycardia within a few seconds and rendered tachycardia noninducible in all patients. A median of two impulses was delivered to each patient. In 69% of patients, postablation atrial stimulation cannot achieve a long atrial-His interval, which previously was critical for tachycardia induction or maintenance. No patient had AVNRT over a follow-up period of 1-16 months, and all had preserved AV conduction. In all except two patients, the PR interval was unchanged. In 47 patients, long-term electrophysiological studies confirmed the efficacy of ablation and the nonreversibility of results by isoproterenol; however, echo beats remained inducible in 40% of patients.

CONCLUSIONS

An area showing slow potentials is present at the perinodal region in humans. In patients with AVNRT, application of radiofrequency energy renders tachycardia noninducible through the preferential modification of the anterograde slow pathway. With present clinical methods, the exact origin and significance of these physiological potentials cannot be specified.

[Potential value of omega-3 polyunsaturated fatty acids in the prevention of atherosclerosis and cardiovascular diseases]

Several epidemiological studies have shown decreased cardiovascular mortality and a lower incidence of coronary artery disease in subjects with high dietary intakes of Omega-3 polyunsaturated fatty acids. It has since been shown that Omega-3 fatty acids have a number of beneficial effects in the prevention of atherosclerosis in man: reduction of blood pressure, modifications of lipoprotein metabolism, modifications of haemostasis (increased bleeding time and reduced platelet aggregation), decreased plasma fibrinogen, modifications of the metabolism of arachidonic acid and its derivatives (decreased thromboxane and leukotriene synthesis, increased prostacyclin synthesis). Therefore, Omega-3 polyunsaturated fatty acids have several beneficial effects on the presumed mechanisms of atherogenesis and/or its complications: they could represent an original and seductive solution to the problem of prevention of cardiovascular disease.

Frequency of recurrent atrial fibrillation after catheter ablation of overt accessory pathways

The effect of successful catheter ablation of overt accessory pathways on the incidence of atrial fibrillation (AF) was studied in 129 symptomatic patients with (n = 75) or without (n = 54) previous documented AF. Fourteen had had ventricular fibrillation. Factors predictive of recurrence were examined, including electrophysiologic parameters. Atrial vulnerability was defined as induction of sustained AF (greater than 1 minute) using single, then double, atrial extrastimuli at 2 basic pacing cycle lengths. When compared to patients with only reciprocating tachycardia, patients with clinical AF included more men (77 vs 54%, p = 0.008) and were older (35 +/- 12 vs 29 +/- 12 years, p = 0.01). They had a significantly shorter cycle length leading to anterograde accessory pathway block (252 +/- 42 vs 298 +/- 83 ms, p less than 0.001), greater incidences of atrial vulnerability (89 vs 24%, p less than 0.001) and subsequent need for cardioversion (51 vs 15%, p less than 0.001). After discharge, the follow-up period was 35 +/- 12 months (range 18 to 76); 7 patients with previous spontaneous AF (9%) had recurrence at a mean of 10 months after ablation. Age, presence of structural heart disease accessory pathway location, atrial refractory periods and accessory pathway anterograde conduction parameters were not predictive of AF recurrence. Persistence of atrial vulnerability after ablation was the only factor associated with further recurrence of AF. Atrial vulnerability was observed after ablation in only 56% of patients with previous AF versus 89% before ablation. It is concluded that successful catheter ablation of accessory pathways prevents further recurrence of AF in 91% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

[Leiomyosarcoma of the right ventricle. Report of a case and review of the literature]

Primary cardiac leiomyosarcoma is a very rare condition. Only 15 cases have been reported in the literature. We report the case of a 27 year old man admitted to hospital for chest pain in March 1985. Echocardiography showed a right ventricular tumour which was completely resected at surgery. The diagnosis of leiomyosarcoma was confirmed by histological examination. After 22 months follow-up, the patient was still alive despite pulmonary metastases. The diagnosis of cardiac tumour used to be made post-mortem but since the introduction of new methods of investigation, especially 2D echocardiography, the diagnosis can be made at an early stage and allows rapid surgical resection, the only means of obtaining the histological diagnosis and of completely curing benign tumours.

Catheter ablation of left posteroseptal accessory pathways and of long RP' tachycardias with a right endocardial approach

Fifty-four patients with a posteroseptal accessory connection and symptomatic tachycardias underwent catheter ablation of the anomalous pathway. Eight had the permanent form of reciprocating tachycardias (long RP' tachycardia) and 46 had a left posteroseptal preexcitation marked by a prominent R wave in lead VI. In 14 of 19 patients, ventriculoatrial conduction time during tachycardia lengthened in conjunction with functional left bundle branch block; this behaviour was significantly different from a series of patients with right posteroseptal preexcitation in which functional left bundle branch block lengthened the ventriculoatrial time in only one of 12 patients. A quadripolar electrode catheter was left within the proximal coronary sinus in order to locate the earliest atrial or ventricular activation site. The appropriate bipole was used as the radiographic and electrophysiological reference of the insertion of the accessory pathway. A catheter was then positioned on the septal side of the right atrium, outside the coronary sinus, so that atrial activity during reciprocating tachycardia and ventricular activity during preexcitation were synchronous with or earlier than that recorded within the proximal coronary sinus. Accessory pathway potential was not recorded in any patient. Early ventricular potential occurring --1.5 +/- 8 ms relative to delta wave onset was present at that site. In 38 patients, including 5 with permanent junctional tachycardia, high current (14 mA) pacing yielded direct ventricular paced QRS complexes (no delay spike-QRS) with a morphology similar to left posteroseptal maximal preexcitation. Slight movements of catheter position yielded significantly different pace-maps. One to eight 160 J cathodal shocks (510 +/- 213 J cumulative per patient) were delivered at this site in 61 sessions. Following fulguration, tachycardia recurred without drugs in only one patient over a follow-up period of 20 +/- 13 months. Asymptomatic intermittent preexcitation recurred in two patients. In all patients with long RP' tachycardia, the ablation procedure was successful without the need for drugs or permanent cardiac pacing. A long-term follow-up electrophysiological study in 18 patients demonstrated that conduction through the anomalous pathway was absent in 16 and deeply altered in the two patients with intermittent preexcitation; no tachycardia was inducible in any patient. In conclusion, catheter ablation of left posteroseptal accessory pathways is a feasible procedure using a right atrial approach outside the coronary sinus. This technique is also effective for the treatment of the permanent form of reciprocating tachycardia.

Electrogram patterns predictive of successful catheter ablation of accessory pathways. Value of unipolar recording mode

BACKGROUND

Transcatheter electrical ablation has been used in the treatment of arrhythmias, and most experience has been obtained by ablating the normal atrioventricular conduction system. Less information is available on ablation of atrioventricular accessory pathways.

METHODS AND RESULTS

Catheter ablation of overt accessory pathways was attempted in 135 patients with 142 distinct pathways, including 21 right parietal or anteroseptal, 47 posteroseptal, and 74 left lateral pathways. We sought to identify the type and value of electrophysiological parameters associated with successful ablation outcome. For this purpose, the unipolar recording mode was used in addition to bipolar anterograde and retrograde parameters. With a mean follow-up of 16 +/- 6 (mean +/- SD) months, fulguration was successful in eliminating preexcitation in 129 patients (96%), including all seven with two distinct accessory pathways. The first ablation attempt was successful in 110 patients, and two or more attempts were performed in 25 patients. Bipolar electrograms associated with success of fulguration showed a shorter atrioventricular conduction time (40 +/- 13 versus 53 +/- 17 msec, p less than 0.0001) and an earlier main ventricular deflection relative to delta wave onset (-1.7 +/- 10 versus 5 +/- 7 msec, p less than 0.001) than electrograms associated with unsuccessful outcome. The only parameter dealing with retrograde conduction (i.e., ventriculoatrial conduction time during reciprocating tachycardia) was not predictive (86 +/- 17 versus 93 +/- 17 msec). Neither was the atrial to ventricular electrogram amplitude ratio. Two unipolar parameters were found to be predictive of successful outcome: 1) The three different patterns PQS, P-QS, P-rS of unipolar waves recorded at the annulus were associated with respective success rates of 97%, 78%, and 55% (p less than 0.001). 2) Intrinsic deflection timing occurred -4 +/- 8 and 6 +/- 7 msec relative to delta wave onset in successful attempts and in failures, respectively (p less than 0.001). Logistic regression analysis revealed a single independent factor predictive of success, the unipolar pattern (p = 0.03), with an odds ratio of 7:1 (PQS pattern versus P-rS pattern). In the group of 18 patients who underwent a first unsuccessful but second successful attempt, comparison of electrograms revealed no difference in the ventriculoatrial conduction time but a significant improvement in anterograde parameters and unipolar pattern distribution.

CONCLUSIONS

Some distinctive electrogram patterns concerning anterograde conduction are associated with success of accessory pathway fulguration. The unfiltered unipolar recording mode (PQS pattern) contributes significantly to optimizing the accuracy of accessory pathway localization.

[Cardiac lesions in AIDS]

The frequency of cardiac lesions in AIDS patients is diversely evaluated. At post-mortem examination macroscopic lesions are said to have been found in 20 percent of the patients, and microscopic lesions in 50 percent. In some clinical studies, up to 55 percent of the patients had echocardiographic abnormalities. All three cardiac wall layers may be involved. Cases of myopericardial Kaposi's sarcoma or non-Hodgkin's lymphoma have been described, together with infectious myocarditis or pericarditis, non-obstructive cardiomyopathy, aseptic fibrinous pericarditis, marantic endocarditis and other, less frequent lesions.

[Post-extrasystolic long QT: evaluation and significance]

The dynamic behaviour of the QT interval was studied in 13 patients with a prolongation of greater than 80 ms of the QT interval of the QRS complex following a post-extrasystolic pause. Normal repolarisation under basal conditions (QTc 410 +/- 30 ms) was significantly (p less than 0.001) prolonged after pauses (QTc 512 +/- 90 ms). The study protocol included the measurement of QT during a Holter recording, an exercise test, Valsalva's manoeuvre and the isoprenalin test. Hydroquidine 600-900 mg/d was given to evaluate its action on ventricular repolarisation. The longest sinus cycles seen on the night Holter tracing (mean: 1,395 +/- 666 ms) were accompanied by normal repolarisation (QTc 380 +/- 30 ms). In contrast, exercise or Valsalva's manoeuvre caused a prolongation of QTc (QTc greater than 460 ms) in 11 patients out of 13: exercise QTc 471 +/- 54 ms; Valsalva QTc 480 +/- 50 ms. No arrhythmia occurred during these dynamic manoeuvres nor during the isoprenalin test. Hydroquinidine (mean: 729 mg) induced a QTc of greater than 500 ms in 6 patients out of 13 (46%). A triplet suggestive of a "torsade de pointes" was seen in one patient only. In conclusion, patients with a post-extrasystolic T wave abnormality under basal conditions were shown to fail to appropriately adapt their QT interval during autonomic stimulation manoeuvres and the prescription of hydroquinidine at the usual dose induced a mean QTc of greater than 500 ms in 46% of them.

Catheter ablation of accessory pathways: technique and results in 248 patients

Two hundred and forty-eight patients with refractory arrhythmias related to an accessory pathway underwent catheter ablation. Cathodal shocks (160 to 240 joules) were delivered through the distal electrode of a standard catheter (usually a quadripolar electrode catheter with 5-mm interelectrode distances). A paddle electrode positioned opposite to the catheter served as the anode. Ablation of 24 right anteroseptal, 16 right parietal, 86 posteroseptal, 120 left parietal and four Mahaim pathways was clinically successful in eliminating symptomatic tachycardia in 236 patients (greater than 96%) over a follow-up of 3 to 64 months. There was no procedure-related death but two patients developed a ventricular fibrillation at the fifth and seventh day, respectively. The latter led to a sudden death since this side effect occurred after discharge. There were no instances of systemic embolus but one pericardial effusion required subxiphoid needle drainage 6 weeks after the procedure. Other complications included: AV block in four patients with posteroseptal and in one with a right anterior septal pathway. In conclusion, a successful clinical outcome may be achieved in most patients. Catheter ablation is an important alternative to cardiac surgery and in our opinion represents first-line treatment when therapy is required.

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)