Radiofrequency catheter ablation of common atrial flutter in 200 patients.

INTRODUCTION: The purpose of this study was to evaluate the efficacy and safety of radiofrequency (RF) catheter ablation of common atrial flutter and to determine the optimum target sites in a large series of patients. Three different approaches were used to target the ablation site. The first used a combined anatomic and electrophysiologic approach, whereas the second and the third approaches relied primarily on anatomic guidelines to target the critical area in the atrial flutter reentrant circuit located in the low right atrium. BACKGROUND: Recent studies report the efficacy of RF current application in the low right atrial region to interrupt and prevent recurrences of common atrial flutter using either anatomic or electrophysiologic targets. However, larger groups of patients are required to confirm the efficacy of this technique and to specify the target sites. METHODS AND RESULTS: Two hundred consecutive patients with drug-resistant common atrial flutter were studied. In the first 50 patients, target sites were localized using both anatomic landmarks and electrophysiologic parameters. The anatomic landmarks were area 1 between the tricuspid valve and inferior vena cava orifice; area 2 between the tricuspid valve and coronary sinus ostium; and area 3 between the inferior vena and coronary sinus. The electrophysiologic criterion was to ablate when there was an atrial electrogram occurring during the plateau phase (preceding F wave). The first targeted area was that giving the more stable catheter position. In the following 30 patients, we assessed the effect of RF energy application in a single line to area 1 in the first 10 patients, area 2 in the next 10, and area 3 in the last 10 patients. In the last 120 patients, RF energy was applied only in area 1 using repeated applications. RF energy of 12 to 30 W, or that achieving a temperature of 70 degrees C, was applied for 60 to 90 seconds at each site. The endpoint of the ablation procedure was interruption and noninducibility of common atrial flutter in the first 110 patients and additional isthmal block in 48 of the last 90 patients. Overall, atrial flutter was interrupted and rendered noninducible after a single session in 191 (95%) patients and could not be interrupted in 9 (4.5%) patients. The mean number of RF applications was 12 +/- 8. After a mean follow-up of 24 +/- 9 months, recurrences occurred in 31 (15.5%) patients, 26 of whom underwent a successful second or third session without further recurrences of atrial flutter. Atrial fibrillation not documented before the ablation was detected in 11 patients. On a retrospective analysis of the final successful site in the first group of 50 patients, the location was in area 1 in 39% of patients; area 2 in 36% of patients, and area 3 in 25% of patients. Atrial electrograms recorded at these sites showed a single spike pattern in 46% of patients, and double spike pattern (28%) or fractioned electrogram in 26% patients. When lines of RF lesions were placed at several sites, they produced a success rate of 70%, 40%, and 10% at areas 1, 2, and 3 respectively. In the last series of 120 patients, the procedure was successful in 119 patients: 92% of whom were successfully treated only by a linear lesion between the tricuspid annulus isthmus and the inferior vena cava, and the other 8% by additional applications near the coronary sinus ostium. No complications were observed. CONCLUSIONS: RF catheter ablation of atrial flutter can be done with a high success rate and is safe. The highest success rate is achieved with RF energy applied in the isthmus between the inferior vena cava orifice and the tricuspid valve. However, 15.5% of patients need multiple sessions to achieve success because of recurrence of flutter. Further follow-up is needed to evaluate the long-term effects of this procedure.

[Survival after His bundle ablation for supraventricular arrhythmia. A 10-years experience in 317 consecutive patients]. / Survie après fulguration du faisceau de His pour arythmie supraventriculaire. Dix ans d'expérience avec 317 patients consécutifs.

Survival after His bundle ablation for supraventricular arrhythmias was analysed over 10 years (May 1982 to December 1992) in 312 consecutive patients (5 were lost to follow-up): 54 died (17.3%), 13 of sudden death (24%). The survival rates were 94.5% at 1 year (n = 256), 80.1% at 5 years (n = 88), 72.8% at 8 years (n = 20) and 51% at 10 years (n = 4); patients without apparent heart disease had a better prognosis. This series serves as a reference for other techniques of His bundle ablation.

Radiofrequency catheter ablation of common atrial flutter in 80 patients.

OBJECTIVES: The purpose of this study was to evaluate the efficacy and safety of radiofrequency catheter ablation of common atrial flutter and to determine the optimal target sites in a large series of patients. BACKGROUND: Recent studies report the efficacy of radiofrequency current application in the low right atrial region to interrupt and prevent recurrences of common atrial flutter. However, larger groups of patients are required to confirm the efficacy of this technique and to specify the target sites. METHODS: Two different approaches were used to target the ablation site in 80 consecutive patients. In the first 50 patients, target sites were localized using both anatomic landmarks and electrophysiologic variables. Three anatomic landmarks were used: area 1 = between the tricuspid valve and inferior vena cava orifice; area 2 = between the tricuspid valve and coronary sinus ostium; area 3 = between the inferior vena cava and coronary sinus. The electrophysiologic criterion was to ablate when there was a stable atrial electrogram during the plateau phase. In the next 30 patients we assessed the effect of application of radiofrequency energy in a single line in area 1, 2 or 3 in groups of 10 patients. RESULTS: Overall atrial flutter was interrupted and rendered noninducible after a single session in 72 patients (90%) and could not be interrupted in 8 (10%). The mean (+/- SD) number of radiofrequency applications was 12 +/- 8. After a mean (+/- SD) follow-up of 20 +/- 8 months, recurrences occurred in 14 patients (17%). The location of the final successful site in the first group of 50 patients was in area 1 in 39%, area 2 in 36% and area 3 in 25%. In the next 30 patients, when lines of radiofrequency lesions were placed at several sites, they produced success rates of 70%, 40% and 10% at areas 1, 2 and 3, respectively. CONCLUSIONS: Radiofrequency catheter ablation of atrial flutter can be performed with a high success rate and is safe. The highest success rate is achieved with radiofrequency energy applied in the isthmus between the inferior vena cava orifice and tricuspid valve.

Characteristics of the ventricular insertion sites of accessory pathways with anterograde decremental conduction properties.

BACKGROUND: Accessory pathways (APs) with anterograde decremental conduction properties referred to as Mahaim fibers have recently been recognized as originating from the right lateral atrium. Little information is available about their distal insertion. The purpose of this study was to determine the different kinds of APs involved and the characteristics of their distal insertion site. METHODS AND RESULTS: Twenty-one patients (mean age, 28 +/- 13 years) with reciprocating tachycardia or atrial fibrillation were studied. Right-sided atrial and/or ventricular endocardial mapping during tachycardia identified different types of APs. (1) Seventeen patients had long APs originating from the right lateral atrium and coursing several centimeters to the right ventricle. In 10 patients, the AP terminated in or close to the right bundle-branch system (atriofascicular AP) and in 7, the AP terminated in the anterior right ventricle (atrioventricular AP). Patients with atriofascicular APs had narrower QRS complexes (133 +/- 10 versus 165 +/- 26 milliseconds, P = .02) and narrower initial r wave in leads V2 through V4 during maximal preexcitation than patients with atrioventricular APs. In addition, they had earlier His-bundle and right bundle-branch retrograde activation, ie, shorter V-His (16 +/- 5 versus 37 +/- 9 milliseconds, P < .01) and V-right bundle intervals (3 +/- 5 versus 25 +/- 6 milliseconds, P < .01). In 6 patients, minimal preexcitation not readily apparent was present in sinus rhythm despite the appearance of a narrow QRS complex. A wide distal insertion site of 0.5 to 2 cm in diameter consistent with arborization of the AP was found in 10 patients. The distal application of radiofrequency current produced a change in the preexcitation pattern in 4 patients and ablated the AP in 2 patients. In the other patients, radiofrequency current was applied more proximally and successfully ablated the AP bundle (n = 9) or AP proximal insertion (n = 6). No recurrence was observed during a follow-up period of 12 +/- 10 months. (2) Four patients had short paratricuspid atrioventricular APs; in one, the decremental conduction property was acquired as demonstrated by two electrophysiological studies performed 7 years apart. Radiofrequency ablation was successfully accomplished in all 4 patients at the tricuspid annulus. CONCLUSIONS: Different types of APs account for tachycardias previously called Mahaim fibers. Long and short atrioventricular APs are observed in 81% and 19%, respectively. Long APs often have a distal arborization and may have either a fascicular or ventricular insertion. Radiofrequency current is more efficient when applied to the AP bundle or AP proximal insertion rather than to the distal insertion in patients with long APs.

[Practical experience of specific catheter ablation of atrial flutter in 110 patients]. / Expérience pratique de l'ablation spécifique du flutter auriculaire chez 110 patients.

The object of this study was to assess the efficacy and risks of radiofrequency ablation of common atrial flutter and to determine the optimal site of ablation in a large population of patients. Three different methods were used to determine the site of ablation: the first was anatomical and electrophysiological whilst the two others were based essentially on anatomical landmarks for localising the critical zone of the reentry circuit. Recent studies report that radiofrequency ablation is effective in interrupting and preventing recurrences of common atrial flutter both by using anatomical and electrophysiological methods. Nevertheless, a larger series of patients was necessary to establish the efficacy and to determine the optimal site of ablation. A series of 110 consecutive patients with common atrial flutter resistant to antiarrhythmic drugs was studied. The site of ablation of the first 50 patients was determined using both anatomical landmarks and electrophysiological parameters. The anatomical zones were: zone 1, between the septal leaflet of the tricuspid valve and the orifice of the inferior vena cava; zone 2, between the septal leaflet of the tricuspid valve and the ostium of the coronary sinus, and zone 3: between the orifice of the inferior vena cava and the ostium of the coronary sinus. The electrophysiological criterion was an endocavitary auriculogramme occurring during the plateau phase preceding the F wave of the flutter.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful catheter ablation of atrial fibrillation.

INTRODUCTION: Catheter ablation of a case of incessant atrial fibrillation was attempted using linear right atrial lesions created by sequential applications of radiofrequency energy. METHODS AND RESULTS: A 46-year-old patient had incessant episodes of atrial fibrillation. He had previously undergone successful radiofrequency catheter ablation of a common atrial flutter. Antiarrhythmic drugs including amiodarone and various drug combinations were ineffective. A 7-French specially designed 14-polar catheter with interelectrode distance of 3 mm was used to create linear lesions in the right atrium. Each electrode was 4 mm in length and able to transmit radiofrequency energy. Three linear lesions, two longitudinal and one transverse that connected the two longitudinal lesions, were created using 30 radiofrequency applications of 10 to 40 W. The final application interrupted an atrial fibrillation that had been persistent for 55 minutes. No sustained atrial fibrillation was inducible despite repeated pacing maneuvers. There was no complication. In short-term follow-up of 3 months, the patient has been free of arrhythmias without antiarrhythmic medication. CONCLUSION: Successful catheter ablation of human atrial fibrillation is feasible using linear atrial lesions created by radiofrequency energy delivery. Further studies are mandatory to ascertain the efficacy and safety of this procedure, as well as to assess different catheter techniques.

Correlation of signal-averaged P wave with electrophysiological testing for atrial vulnerability in strokes of unexplained etiology.

UNLABELLED: Atrial fibrillation is considered the main cause of cardioembolic strokes. After detailed investigations, about 30% of ischemic strokes remain unexplained. A percentage of these ischemic attacks may result from asymptomatic episodes of paroxysmal atrial fibrillation (PAF). Previous studies have demonstrated that electrophysiological testing and signal-averaged P wave (SAPW) ECG are useful to detect patients with PAF. METHODS AND RESULTS: Twenty patients with unexplained ischemic strokes had electrophysiological studies (EPS) to determine atrial vulnerability and SAPW recordings. At EPS, patients were classified in group I (10 patients) if they had a latent atrial vulnerability index < 2 and/or more than 1 minute of sustained atrial arrhythmia. Otherwise they were classified in group II (10 patients). In group I, the filtered P wave duration was greater: 142 versus 120 msec (P = 0.03) and RMS 30 tended to be lower: 2.54 versus 4.13 microV (P = 0.11) than in group II. A filtered P wave duration > 125 msec associated with a RMS 30 < 3 microV had a positive predictive value of 78% and a negative predictive value of 88% for the detection of patients with abnormal atrial vulnerability at EPS. CONCLUSIONS: SAPW may be useful to identify patients at risk of PAF who may be candidates for EPS.

Long-term survival after closed-chest His-bundle ablation with DC shock for supraventricular arrhythmias: a 10-year experience with 317 consecutive patients.

Survival after closed-chest ablation of His bundle with DC shock for supraventricular arrhythmias was analyzed for a 10-year period (May 1982-December 1992) with 317 consecutive patients (167 males, 150 females; mean age 66 years; range 33-93 years). Of these, 54 patients died (17.3%) and 5 were lost to follow-up. The mean age at ablation was 70.3 +/- 8.3 years with a range of 49-93 years. Of those who died, the mean survival was 30.5 +/- 28.6 months with a range of 36 hours to 120 months; the diagnosis of heart disease was: hypertension (n = 14), cardiomyopathy (n = 8), ischemic (n = 7), valvular (n = 6), cor pulmonale (n = 3), valvular and ischemic (n = 2), hypertension and ischemic (n = 1), miscellaneous (n = 3), and none (n = 10). Of the patients who died after ablation, the arrhythmias at the time of the ablation were atrial fibrillation (AF; n = 33), sick sinus syndrome (n = 5), atrial flutter (AFL; n = 4), paroxysmal AV junctional tachycardia (PAVJT; n = 4), AF + AFL (n = 4), atrial tachycardia (n = 2), PAVJT + AFL (n = 1), and AF +AFL + atrial tachycardia (n = 1). Death was sudden in 13 patients (25%), due to heart failure in 10 (19.2%), myocardial infarction in 4 (7.7%), stroke in 4 (7.7%), aortic vascular accident in 3 (5.8%), miscellaneous in 18 (34.6%), and undetermined in 2.(ABSTRACT TRUNCATED AT 250 WORDS)

[Ablation of the accessory pathways by radiofrequency currents]. / Ablation des voies accessoires par courants de radiofréquence.

The introduction of ablative methods has revolutionised therapeutic strategy in cardiac arrhythmias. Accessory pathways are the most commonly targeted arrhythmogenic substrate. Several parameter may be used to determine the optimal site of ablation: accessory pathway potential, atrioventricular interval, atrial or ventricular pole of the pathway, morphology of the unipolar wave. The localisation of the accessory pathway sometimes requires specific techniques. The success rate reported in the literature is generally over 90%. However, the number of applications of radiofrequency current varies according to the authors from an average of three to eight. A combination of "timing related" criteria and direction of activation and the use of infraliminal stimuli minimise the number of radiofrequency applications. The incidence of complications in multicenter registers is 5% and the relapse rate is 8%. The long-term effects of catheter ablation are unknown, especially when used in childhood. A certain reserve should be maintained in the indications of ablation. Only high-risk, life-threatening arrhythmias, or those resistant to pharmacological intervention, are formal indications. Other (so-called "convenience") indications depend on the express wish of patients clearly informed of the advantages and risks of this method.

[Choice of the mode of stimulation after ablation of the bundle of His. Experience based on a retrospective survey of 192 patients]. / Choix du mode de stimulation après ablation du faisceau de His. Expérience tirée d'une enquête rétrospective portant sur 192 malades.

A retrospective study of 192 patients centered on the outcome of supraventricular arrhythmias after catheter ablation of the atrioventricular junction provided some useful information concerning the choice of pacing mode in these patients. With the exception of atrioventricular bloc after ablation of the rapid nodal pathway where simple DDD pacing is adequate, rate adaptive pacing would seem to be essential. The VVIR mode should be the mode of choice in atrial flutter, permanent atrial fibrillation, poorly controlled atrial fibrillation and paroxysmal atrial fibrillation of elderly subjects (over 70 years) and/or of male sex, and/or complicating advanced cardiac disease (valvular, ischaemic or primary). The DDDR mode (with an algorithm to prevent endless loop tachycardia) is the mode of choice in sinus node dysfunction and/or in young patients (under 60), and/or females and/or in idiopathic arrhythmias and/or when retrograde VA conduction persists. When the pacemaker is replaced, the indication should be reviewed with respect to the outcome of the arrhythmia, which underlines the value of accurate implanted Holter systems.

Electrocardiographic characteristics and catheter ablation of parahissian accessory pathways.

BACKGROUND: Accessory pathways may be located in close proximity to the His bundle, resulting in a high risk of heart block during attempted surgical or electrical interruption of these pathways. This study reports the prevalence, ECG characteristics, and results of catheter ablation of parahissian accessory pathways. They were defined on the basis of both the presence of a high amplitude (> 0.1 mV) of His bundle potential at the ablation site and an exclusion of anteroseptal or midseptal location of the accessory pathway. METHODS AND RESULTS: Eight patients with a parahissian accessory pathway were identified among 582 consecutive patients who underwent radiofrequency ablation of an accessory pathway. They were six males and two females with a mean age of 21 +/- 9 years. During maximal preexcitation, the ECG showed a positive delta wave in leads I, II, and a VF in all patients: six had a negative delta wave in leads V1 and V2 instead of the positivity usually observed in anteroseptal accessory pathways. This pattern had a sensitivity of 75%, a specificity of 96%, a positive predictive value of 86%, and a negative predictive value of 93% for a parahissian location in comparison with a group of 28 patients with anteroseptal accessory pathways. At the successful ablation site, the mean amplitude of the His bundle potential was 0.2 +/- 0.1 (0.12 to 0.4 mV). All accessory pathways were successfully ablated without causing heart block using 5 to 20 W of radiofrequency energy. CONCLUSIONS: Parahissian accessory pathways have a preexcitation pattern that is distinctive from that of anteroseptal accessory pathways. Catheter ablation of these pathways is feasible using low energy with preservation of normal atrioventricular conduction.

[Atrial fibrillation, restoration of sinus rhythm]. / Fibrillation auriculaire, restauration du rythme sinusal.

Conversion to sinus rhythm (cardioversion) is recommended to prevent the haemodynamic and thromboembolic complications of atrial fibrillation. Prior anticoagulation is compulsory except in emergencies. The duration of anticoagulant therapy depends on the terrain and chronicity of the arrhythmia. Cardioversion may be proposed for the majority of patients in whom it is thought that sinus rhythm can be maintained by appropriate therapy. It may be carried out pharmacologically by oral or intravenous antiarrhythmic therapy. Amiodarone is the drug of choice. Cardioversion may also be carried out by external or internal direct current shock. The success rate of external electrical defibrillation depends on the energy administered, the site of the electrodes and a number of factors related to thoracic impedence. Internal electrical defibrillation may be performed with an endocavitary catheter or by the oesophageal approach, with few complications. The main problem resides in maintaining sinus rhythm in the long term. When this is not possible, cardioversion is useless, and therapy to slow the cardiac rhythm should be instituted.

[Mechanisms of ventricular tachycardia]. / Mécanismes des tachycardies ventriculaires.

There are three fundamental mechanisms of ventricular tachycardia (VT) reentry, abnormal automaticity and triggered activity (TA) related to early or late after potentials. Reentry is certainly the mechanism of branch to branch and post-infarction VT. Early TA is responsible for Torsades de Pointes. Late TA is possibly the cause of certain verapamil-responsive VT but calcium-dependent reentry cannot be excluded. Abnormal automaticity or late TA may also play a role in catecholamine-induced VT. The development of drugs specific for the mechanism confronted with the results of programmed stimulation and mapping should improve the understanding of the mechanism of VT in each individual patient and allow more effective and better tolerated antiarrhythmic therapy.

The antiarrhythmic effect of the ACE inhibitor captopril in patients with congestive heart failure largely is due to its potassium sparing effects.

OBJECTIVE: To evaluate the mechanisms by which the angiotensin converting enzyme (ACE) inhibitor captopril may modify the presence of ventricular arrhythmias in patients with chronic heart failure. PATIENTS: Forty-seven patients with chronic stable congestive heart failure. METHODS: Twenty-four hour Holter monitoring was done prior to and after one month of therapy with the ACE inhibitor captopril. In a first group of 25 patients, changes in the incidence of ventricular arrhythmias were correlated with changes in cardiac hemodynamics (assessed invasively). In a second group of 22 patients, changes in ventricular arrhythmias were correlated with changes in echocardiographic measurements. In all patients serum potassium was kept constant, and changes in exercise tolerance and serum noradrenaline levels were assessed prior to and after captopril. RESULTS: One month of captopril therapy caused an improvement in cardiac hemodynamics and in exercise tolerance. It also led to a tendency for improved echocardiographic measurements and serum noradrenaline levels, similar to those already published by others. However, no change in the incidence or severity of ventricular arrhythmias was detected. No correlation could be found between changes in ventricular arrhythmias and any of the variables measured. CONCLUSIONS: As the only obvious difference between this and previous studies that documented a decrease in ventricular arrhythmias when ACE inhibitors were started in patients with congestive heart failure is a lack of change in serum potassium in this study, the current results suggest that the major antiarrhythmic effect of ACE inhibitors in patients with congestive hear failure is the result of their potassium sparing effects.