[The coexistence of a para hisian accessory pathway and a complete atrioventricular block in a 32 years old patient]. / Un faisceau accessoire chez un patient de 32ans pas si accessoire !

The present case report describes a 32-year-old patient with complete atrioventricular block coexisting with a permanent ventricular preexcitation. The patient ended up with pacemaker implantation without requiring ablation of accessory pathway.

Transvenous cryo-ablation of the slow pathway for the treatment of atrioventricular nodal re-entrant tachycardia: a single-centre initial experience study.

AIMS: Within the last several years, transvenous cryo-ablation has become an alternative method to perform ablation of the slow-pathway. This study evaluated the acute and long-term safety and effectiveness of atrio-ventricular nodal re-entrant tachycardia (AVNRT) cryo-ablation. METHODS AND RESULTS: The first 69 consecutive patients with AVNRT (60 slow-fast, 4 fast-slow, and 5 slow-slow) who underwent slow-pathway cryo-ablation were included. Mean age was 37 +/- 15, body weight 68 +/- 14 kg, symptom duration 125 +/- 104 months, and number of ineffective antiarrhythmic (AA) drugs 1.8 +/- 1.4. A 7 Fr cryo-catheter (Cryocath(A)) was used, with initially 4-mm-tip and later with 6-mm-tip electrode. Cryo-mapping (n = 7.9 +/- 8.4 per pt) was performed at the temperature of -30 degrees C to test the effect on the target ablation site. Successful cryo-mapping was defined as abolition of nodal conduction jump or AV nodal refractory period prolongation. Cryo-ablation (n = 5.1 +/- 4.9 per pt) was then applied by freezing to -75 degrees C for 4 min in duration if no AV-block occurred. Acute procedural success (defined as AVNRT non-inducibility) after the first cryo-ablation attempt was achieved in 60/69 patients (87%). During cryo-ablation, inadvertent transient AV-block was encountered in 14 patients (five I AV-block and nine II-III AV-block). A mid-septal target site was the only variable correlated with inadvertent AV-block occurrence during cryo-ablation (P < 0.02). Long-term clinical success after cryo-ablation was globally achieved in 56/66 (85%) with a mean follow-up of 18 +/- 9 months (3 pts dropped-out). After the first procedure, 41/66 (62%) had no relapse, eight had a dramatic reduction in AVNRT duration-frequency and considered themselves cured, and five needed previously ineffective AA (with no relapse in three, drastic reduction in AVNRT duration-frequency in two). The five last patients needed one or more procedures, after which one had no recurrence and one had reduction in duration-frequency. Absence of recurrence after the first procedure was positively correlated with 6-mm-tip cryo-catheter use (<0.001) and negatively with acute procedural success (<0.001). At multivariate analysis, both were independently significant (<0.04 and <0.008, respectively). Long-term clinical success was correlated only with 6-mm-tip cryo-catheter use (<0.001). CONCLUSIONS: Slow pathway cryo-ablation is associated with an acute success but a higher recurrence rate. A 6-mm-tip cryo-catheter seems to assure during cryo-ablation a large acute and long-term success. AV-block seems non-guaranteed by a negative cryo-mapping, stressing on need of a careful surveillance. Nevertheless, the theoretical advantage of avoiding the risk of permanent AV-block when compared with radiofrequency needs larger series to be demonstrated.

[Hypertension and age over 70 years are the two most important risk factors for stroke in patients with atrial fibrillation]. / L'hypertension artérielle et un âge de plus de 70 ans sont les principaux facteurs de risque d'accidents vasculaires cérébraux chez les patients en fibrillation auriculaire.

In a registry of 250 patients treated for atrial fibrillation (160 recurrent, 90 permanent forms), we prospectively looked for associated risk factors for cerebrovascular complications. After a 4-years follow-up, 19 patients had presented a cerebral accident (13 strokes, 4 transient ischemic attacks, 2 cerebral hemorrhages). Prognostic factors for cerebrovascular complications were hypertension, valvular heart disease, and age > or = 70 years. When restricting the analysis to stroke and transient ischemic attacks, prognostic factors were limited to hypertension and age > or = 70 years. In conclusion, hypertension and age > or = 70 years are the main independent risk factors for cerebral ischemic attacks in out-of-hospital patients treated for atrial fibrillation.

[Atrial vulnerability: a new protocol by bigeminy pacing]. / Vulnérabilité atriale: un nouveau protocole par stimulation bigéminée.

INTRODUCTION: There is little information available on the events that mediate short term remodeling. In a bigeminy atrial-pacing protocol, we sought to evaluate the electrophysiological consequences of an irregular short-long cycle length atrial pacing. METHODS AND RESULTS: This study included 22 consecutive patients with documented arrhythmias and 10 control subjects. After evaluating the effective and functional refractory periods, bigeminy atrial pacing was performed for 5 min. During bigeminy pacing, in 12 AF patients and in none of the control subjects, AF was started lasting longer than 1 minute (Group I). Short salvos of AF occurred in five patients and three controls (Group II) and no arrhythmia occurred in five patients and seven controls (Group III). Sensitivity, specificity, negative and positive predictive values of sustained AF induced by bigeminy pacing were 54%, 100%, 50% and 100%, respectively. Atrial refractory periods measured immediately after termination of 5 minutes of bigeminy pacing were shorter than during baseline. The degree of shortening was similar in AF patients and in controls. The loco-regional conduction did not change after the bigeminy protocol. CONCLUSION: This study demonstrates that atrial bigeminy pacing unmasks latent atrial vulnerability.

Autonomic influences on ventricular repolarization in congestive heart failure.

We studied the QT interval rate-dependence in patients with congestive heart failure (CHF). The long-term autonomic nervous function was investigated by separate analysis of diurnal and nocturnal periods. For this purpose, QTm rate-dependence was determined from Holter recordings. Twelve patients with stable CHF (mean age 63 +/- 2 years) and 15 healthy subjects (mean age 59 +/- 4 years) were included in the study. CHF patients showed an increased nocturnal QTm rate-dependence when compared to normal subjects (0.150 [95% confidence interval (CI) 0.114 to 0.186] versus 0.106 [95% CI 0.080 to 0.133], P < .05). In contrast, QTm rate-dependence was not significantly different between the 2 groups during the day (0.177 [95% CI 0.149 to 0.210] in the CHF group versus 0.194 [95% CI 0.158 to 0.231] in the control group). It was also not significantly different between day and night for the CHF group, thus showing a loss of the circadian modulation in these patients. Thus, ventricular myocardial properties are altered by changes in the autonomic nervous system in CHF, as observed at the atrial level. These modifications may be related to the increased susceptibility to ventricular arrhythmias.

[Indications of automatic ventricular implantable defibrillator. Implications for daily practice]. / Les indications du défibrillateur automatique implantable ventriculaire. Implications pour la pratique quotidienne.

The authors were the redactors of the Guidelines of the French Society of Cardiology for the indications of the automatic implantable defibillator, derived from the available indication in USA, and from the ulteriorly performed controlled studies. Three Class-I indications were selected: 1) circulatory arrest due to ventricular tachycardia (VT) or fibrillation (VF) whithout acute curable aetiology. 2) sustained VT with underlying heart disease and contractile alterations. 3) non-sustained VT with prior myocardial infarction and LVEF < 35% with inductible despite maximal drug therapy. Class-II indications were also three: 1) inheritable disease with high risk of sudden death without known effective therapy. 2) Syncope in patients with underlying heart disease and inductible VT or VF during electrophysiologic study. 3) VT or VF in patients in list for heart transplant.

Electrophysiological characteristics of the atrium in sinus node dysfunction with and without postpacing atrial fibrillation.

In patients with sinus node dysfunction (SND) with or without associated paroxysmal atrial fibrillation (AF), the effectiveness of atrial pacing in reducing the incidence of AF is not definitive. In addition, despite several studies involving large populations of implanted patients, little attention has been paid to the electrophysiological (EP) atrial substrate and the effect of permanent atrial pacing. The aim of this study is to correlate EP data and the risk of AF after DDD device implantation. We reviewed EP data of 38 consecutive patients with SND, mean age 70 +/- 8 years, who were investigated free of antiarrhythmic treatment, for the evaluation of the atrial substrate. We also considered as control group 25 subjects, mean age 63 +/- 14 years, referred to our EP laboratory for unexplained syncope or various atrioventricular disturbances. Following pharmacological washout and at a drive cycle length of 600 ms, effective and functional refractory periods (ERP, FRP), S1-A1 and S2-A2 latency, A1 and A2 conduction duration, and latent vulnerability index (ERP/A2) were measured. AF induction was tested with up to three extrastimuli at paced cycle lengths of 600 and 400 ms in 20 patients. Induction of sustained AF (> 30 seconds) was considered as the endpoint. P wave duration on the surface ECG in lead II/V1 was also measured. DDD pacing mode was chosen in all patients with the minimal atrial rate programmed between 60 and 75 beats/min (mean 64 +/- 4 beats/min). After implantation, the patients were followed-up for 29 +/- 17 months and clinically documented occurrence of AF was determined. When comparing patients with SND and subjects of the control group, we did not find any significant statistical differences in terms of ERP (237 +/- 33 vs 250 +/- 29 ms), FRP (276 +/- 30 vs 280 +/- 32 ms) and S1-A1 (39 +/- 16 vs 33 +/- 11 ms) and S2-A2 latency (69 +/- 24 vs 63 +/- 25 ms). In contrast, we observed significant differences regarding A1 (55 +/- 19 vs 39 +/- 13 ms; P < 0.001), A2 (95 +/- 34 vs 57 +/- 18 ms; P < 0.001) and P wave duration (104 +/- 18 vs 94 +/- 15 ms; P < 0.05), and ERP/A2 (2.8 +/- 1.2 vs 4.8 +/- 1.6; P < 0.001). When comparing patients with (n = 11) or without (n = 27) postpacing AF occurrence, we did not find any difference with reference to ERP, FRP, S1-A1, S2-A2, A1 duration, or follow-up duration. In patients with postpacing AF occurrence, A2 was longer (116 +/- 41 vs 87 +/- 27 ms; P < 0.01), ERP/A2 lower (2.1 +/- 0.4 vs 3.1 +/- 1.4; P < 0.05), P wave more prolonged (116 +/- 22 vs 99 +/- 14 ms; P < 0.01), and preexisting AF history predominant (6/11 vs 5/27 patients; P < 0.05). No difference was observed between patients with (n = 8) and without (n = 12) AF induction during the EP study. In patients with SND, the atrial refractoriness appears normal and the most important abnormality concerns conduction slowing disturbances. Persistence of AF despite pacing stresses the importance of mechanisms responsible for AF not entirely brady-dependent. In this setting, more prolonged atrial conduction disturbances, responsible for a low vulnerability index, and a preexisting history of AF enable us to identify a high risk patient group for AF in the follow-up.

Electrophysiologic characteristics of the atrium in sinus node dysfunction: atrial refractoriness and conduction.

INTRODUCTION: Clinical electrophysiology (EP) has focused attention on the EP properties of atrial muscle in patients with atrial fibrillation (AF). Patients with sinus node dysfunction (SND) sometimes are included in these studies, but the characteristics of these patients with SND alone appear less well investigated. METHODS AND RESULTS: We reviewed EP data of 46 patients (mean age 70 +/- 8 years) with SND, who underwent EP study for evaluation of the atrial substrate. In 16 patients, a history of paroxysmal AF was documented, but not in the remaining 30 patients who had SND alone. We considered as control a group of 25 subjects (mean age 63 +/- 14 years), who were referred to our EP laboratory for unexplained syncope or AV conduction disturbances. Following pharmacologic washout and at a drive cycle of 600 msec, effective (ERP) and functional refractory periods (FRP), S1-A1 and S2-A2 latency, A1 and A2 width, latent vulnerability index (ERP/A2), and P wave duration on the surface ECG were measured. Intra-atrial conduction times were measured from the stimulus artifact by pacing the high right atrium (HRA), to the corresponding atriograms at the AV node (HRA-AVN), low lateral atrium (HRA-LLA), and low interatrial septum close to the coronary sinus ostium (HRA-CSO). Compared with the control group, SND patients did not show differences in ERP (238 +/- 26 msec vs 250 +/- 29 msec), FRP (274 +/- 25 msec vs 280 +/- 32 msec), S1-A1 (38 +/- 15 msec vs 33 +/- 11 msec) and S2-A2 latency (67 +/- 24 msec vs 63 +/- 25 msec), or HRA-AVN (81 +/- 24 msec vs 65 +/- 19 msec), HRA-LLA (36 +/- 30 msec vs 40 +/- 27 msec), and HRA-CSO (77 +/- 17 msec vs 80 +/- 15 msec) conduction times. In contrast, we observed strong differences in atriogram durations A1 (59 +/- 19 msec vs 39 +/- 13 msec; P < 0.001) and A2 (92 +/- 28 msec vs 57 +/- 18 msec; P < 0.001), as well as in the latent vulnerability index ERP/A2 (2.8 +/- 1.2 msec vs 4.8 +/- 1.7; P < 0.001). Also, the P wave was slightly longer (104 +/- 18 msec vs 94 +/- 45 msec; P < 0.05). No significant statistical difference in EP parameters was found between SND patients with or without documented AF. CONCLUSION: In patients with SND, atrial refractoriness appears similar to that of control subjects. The most important EP abnormality appears to be local conduction slowing disturbances, with prolonged basal and postextrastimuli atriograms, responsible for a lower vulnerability index. This could explain, at least in part, the tendency of patients with SND to develop AF during their natural history. Normality of atrial refractoriness, in contrast to atrial conduction disorders, might explain why atrial pacing shows a preventative effect on the development of AF and why antiarrhythmic drugs often are ineffective.

Electrophysiological determinants of atrial fibrillation in sinus node dysfunction despite atrial pacing.

AIMS: The effectiveness of atrial pacing in reducing the incidence of atrial fibrillation in patients with sinus node dysfunction is incomplete, and the correlation between electrophysiological atrial properties and the effect of permanent atrial pacing has been poorly investigated. Accordingly, the aim of the present study was to correlate electrophysiological data, in terms of atrial refractoriness, conduction parameters, and propensity to atrial fibrillation induction, and the likelihood of atrial fibrillation after DDD device implantation. METHODS AND RESULTS: The authors reviewed electrophysiological data of 41 patients with sinus node dysfunction (mean age 70 +/- 8 years, who were investigated free of anti-arrhythmic treatments before pacemaker implantation. At a drive cycle length of 600 ms, effective and functional refractory periods, S1-A1 and S2-A2 latency, A1 and A2 width, and latent vulnerability index (effective refractory period [ERP] A2), were measured. Atrial fibrillation induction was tested with up to three extrastimuli in 34 patients. Induction of sustained atrial fibrillation (> 1 min) was considered as the end-point. P-wave duration on the surface ECG in lead II/V1 was also measured. Minimal atrial rate was programmed between 60 and 75 bpm (mean: 64 +/- 4 bpm). After implantation, the patients were followed-up for 28 +/- 17 months, and ECG-documented occurrence of atrial fibrillation was determined. Electrophysiological characteristics of patients with (n = 12) or without (n = 29) paroxysmal atrial fibrillation before implantation were similar. When comparing patients with (n = 11) or without (n = 30) post-pacing atrial fibrillation occurrence, no differences were found in age, underlying heart disease, left atrial size, minimal pacing rate, and follow-up duration. Additionally, between the two former groups, there was no significant difference in terms of effective refractory periods (233 +/- 47 ms vs 239 +/- 25 ms), functional refractory periods (280 +/- 48 ms vs 272 +/- 21 ms), S1-A1 (44 +/- 20 ms vs 37 +/- 13 ms) and S2-A2 latency (77 +/- 28 ms vs 66 +/- 22 ms), and A1 duration (60 +/- 23 ms vs 53 +/- 16 ms). In contrast, in patients with post-pacing atrial fibrillation occurrence, the P wave was more prolonged (116 +/- 22 ms vs 98 +/- 13 ms; P < 0.01), A2 was longer (116 +/- 41 ms vs 87 +/- 27 ms; P < 0.01), effective refractory periods/A2 was lower (2.1 +/- 0.4 cm vs 3.1 +/- 1.4 cm; P < 0.05), and rate of atrial fibrillation induction was higher (8/11 patients vs 8/23 patients; P < 0.05). Electrophysiological characteristics of patients free of post-pacing atrial fibrillation with associated (n = 6) or unassociated (n = 24) paroxysmal atrial fibrillation history before implantation were quite similar. In patients with post-pacing atrial fibrillation with associated (n = 6) or unassociated atrial fibrillation history (n = 5) before implantation, effective refractory periods was statistically different (207 +/- 23 ms vs 264 +/- 46 ms; P < 0.05). Values of effective refractory periods < 220 ms were significantly more frequent in patients with post-pacing atrial fibrillation than in patients without (4/11 patients vs 2/30 patients; P < 0.05). When comparing patients with post-pacing atrial fibrillation with effective refractory periods > or = 220 ms (n = 7) and < 220 ms (n = 4), A2 duration was remarkably prolonged (145 +/- 42 ms vs 90 +/- 11 ms; P < 0.05) in those with effective refractory periods > or = 220 ms. By contrast, between the two groups, effective refractory periods/A2 were identical (2.08 +/- 0.6 cm vs 2.15 +/- 0.3 cm; P = n.s.). CONCLUSION: Prolonged atrial refractoriness, lesser degrees of conduction disturbance and a lower rate of atrial fibrillation induction seem to be predictive of stable sinus rhythm. In contrast, patients with persistence of atrial fibrillation despite pacing have a more abnormal and inhomogeneous atrial substrate, as well as a higher rate of atrial fibrillation induction. Prolonged P wave, shortened refractoriness, or remarkably abnormal conduction disturbances in the presence of prolonged refractoriness limit the effectiveness of standard atrial pacing in atrial fibrillation prevention. Identification of predictive criteria of failure of single-site atrial pacing may be used to consider dual-site atrial pacing in such patients with sinus node dysfunction.

Is dual site better than single site atrial pacing in the prevention of atrial fibrillation?

Long-term prevention of atrial fibrillation is not constantly realized by single-site right atrial pacing, and the beneficial role of multisite atrial pacing is still being studied. Accordingly, we compared the effectiveness of dual site and single site atrial pacing in 83 patients (50 men, 33 women, aged 69 +/- 10 years), who received a DDD device for primary sinus node dysfunction or bradycardia with documented atrial fibrillation. Inclusion criteria for dual site pacing were a sinus P wave > or = 120 ms and at least two episodes of documented paroxysmal AF in the 6 months preceding implantation. Dual site atrial pacing (high right atrium-coronary sinus ostium) was performed in 30 cases, and was compared to 53 single site paced patients, 21 with a P wave > or = 120 ms and 32 with a P wave < 120 ms. The basic pacing rate was programmed at 68 +/- 4 beats/min (range 60-75 beats/min). Sinus P wave (133 +/- 20 vs 95 +/- 9 ms; P < 0.001), paced P wave (107 +/- 14 vs 99 +/- 15; P < 0.05), number of antiarrhythmic drugs used (2.4 +/- 1.2 vs 1.6 +/- 1.5, P < 0.05), and the duration of symptoms (8.1 +/- 4.5 vs 3.8 +/- 2.4 years; P < 0.001) were significantly higher in dual site patients. The other characteristics were similar. During the follow-up of 18 +/- 15 months (range 3-30 months), paroxysmal AF was documented in 33 patients. Among these patients, 13 developed permanent AF following at least one episode of paroxysmal AF. When comparing dual site patients and single site patients with a P wave duration > or = 120 ms, paroxysmal AF incidence was lower in the dual site group (9/30 patients vs 15/21 patients, P < 0.01), as well as permanent AF (1/30 patients vs 8/21 patients, P < 0.01). By contrast, comparison between dual site patients and the group of single site patients with a P wave duration < 120 ms did not evidence any significant differences in paroxysmal (9/30 patients vs 9/32 patients) and permanent (1/30 patients vs 4/32 patients) AF incidences. Dual site seems better able than single site atrial pacing to improve the natural history of patients with a prolonged P wave, reducing the incidence of paroxysmal and permanent AF. No benefit could be expected in patients with a normal P wave duration.

Sick sinus syndrome with and without atrial fibrillation: atrial refractoriness and conduction characteristics.

BACKGROUND: Clinical electrophysiology has focused the attention on the electrophysiological properties of the atrial muscle in patients with atrial fibrillation: shortened and inhomogeneous refractoriness and local and regional conduction slowing, as well as prolonged intra- and interatrial conduction disturbances, are well described as electrophysiological parameters associated with the genesis of atrial fibrillation. Patients with sick sinus syndrome are variously included in these studies, but electrophysiological characteristics of patients with sick sinus syndrome alone appear less investigated, even if atrial fibrillation is part of its natural history. The aim of the present study was to define the electrophysiological characteristics of sick sinus syndrome patients with or without paroxysmal atrial fibrillation, compared to subjects without atrial fibrillation and sick sinus syndrome. METHODS: We reviewed the electrophysiological data of 39 patients with sick sinus syndrome (mean age 70 +/- 8 years), who underwent an electrophysiological study in sinus rhythm for the evaluation of the atrial substrate. In 12 patients an associated history of paroxysmal atrial fibrillation was documented. Twenty-seven patients were included in the study with a diagnosis of sinus node dysfunction alone. We also considered as control group 25 subjects (mean age 63 +/- 14 years), referred to our electrophysiological laboratory for unexplained syncope or atrioventricular disturbances. Following pharmacological wash-out and at a drive cycle of 600 ms, effective and functional refractory periods, S1-A1 and S2-A2 latency, A1 and A2 width, and the latent vulnerability index (effective refractory period/A2), were measured. In addition, the P-wave duration during spontaneous sinus rhythm on the surface ECG in D II/V1 leads was measured. RESULTS: Between sick sinus syndrome patients with or without atrial fibrillation, no significant statistical differences in electrophysiological parameters were found. When compared to the control group, sick sinus syndrome patients did not show any differences in effective refractory period (239 +/- 34 vs 250 +/- 29 ms), functional refractory period (276 +/- 28 vs 280 +/- 32 ms), S1-A1 (38 +/- 16 vs 33 +/- 11 ms), and S2-A2 latency (68 +/- 25 vs 63 +/- 25 ms). In contrast, we observed remarkable differences in terms of atriogram duration A1 (60 +/- 20 vs 39 +/- 13 ms, p < 0.001), A2 (95 +/- 34 vs 57 +/- 18 ms, p < 0.001), and effective refractory period/A2 (2.8 +/- 1.2 vs 4.8 +/- 1.7 cm, p < 0.001). Also the duration of the P wave was longer (103 +/- 17 vs 94 +/- 45 ms, p < 0.05). CONCLUSIONS: In sick sinus syndrome patients with or without atrial fibrillation, electrophysiological characteristics appear homogeneous. When compared to the control group, refractoriness was quite similar. In contrast, the most important abnormalities appear based on conduction slowing disturbances, responsible for a low latent vulnerability index. This could explain, at least in part, the tendency of sick sinus syndrome to develop atrial fibrillation as a part of its natural history. At present, the influence of an altered electrophysiological substrate on pharmacological or pacing therapy in patients with sick sinus syndrome is not yet known.

[The effects of the ablation of atrial flutter in patients with and without a clinical history of paroxysmal atrial fibrillation]. / Effetti dell'ablazione di flutter atriale in pazienti con e senza storia clinica di fibrillazione atriale parossistica.

BACKGROUND: Although the safety and effectiveness of radiofrequency (RF) transcatheter ablation in patients with atrial flutter (AFL) is well established, little attention is paid to previous history of associated paroxysmal atrial fibrillation (AF) and the recurrence of AFL after RF ablation. In addition, it is not known whether the elimination of AFL can modify the natural history of AF in patients who experience both of these arrhythmias. Accordingly, the aim of this study was to evaluate the effect of RF ablation of AFL in patients with or without a previous history of AF in terms of the incidence of both arrhythmias in the follow-up. METHODS: RF ablation of the atrial isthmus between tricuspid ring, coronary sinus os and inferior vena cava was performed in 27 patients (23 males, 4 females; mean age 61 +/- 9 years) according to the technique described by Cosio. Based on ECG pattern, twenty patients exhibited common or type 1 AFL (negative F waves in the inferior leads with a sawtooth morphology), while seven patients had both common and uncommon AFL (various surface F wave morphologies, generally positive F waves in the inferior leads). A history of association between AFL and paroxysmal AF was documented in 48% of patients, but AFL was the major arrhythmia. After ablation, the patients were followed up and the clinically documented occurrence of arrhythmias was determined. RESULTS: Based on clinical history before ablation, we compared patients with an association between AFL and AF (Gr AFL + AF; n = 13) vs patients with only AFL (Gr AFL; n = 14). The characteristics of the two groups were similar regarding age, sex, duration of symptom, structural heart disease, left atrial size, P-wave duration, AFL interruption during RF procedure, antiarrhythmic treatment before and after RF procedure, and duration of follow-up. During a follow-up of 12 +/- 6 months, AFL recurred in 10 patients (37%), 4 from Gr AFL + AF, and 6 from Gr AFL (p = NS). Episodes of paroxysmal AF occurred in 6 patients (22%), 5 from Gr AFL + AF and 1 from Gr AFL (p < 0.05). In Gr AFL + AF, the incidence of AF after ablation was significantly lower (1.8 +/- 0.6 vs. 0.7 +/- 1 episodes/year; p < 0.02). Characteristics of patients with or without AFL recurrence in the follow-up were similar. The percentage of patients with the occurrence of AFL or AF, associated or unassociated in the follow-up, was 55%. CONCLUSIONS: A history of paroxysmal AF before RF ablation of AFL is not predictive of long-term success or failure of the procedure when considering the recurrence of AFL alone. Nevertheless, the general results are disappointing because the majority of patients have arrhythmias, AFL or AF, associated or unassociated in the follow-up. A clinical history of AF before ablation is correlated with a higher incidence of AF in the follow-up. In any event, the incidence of AF episodes is lower in the follow-up, indicating a possible beneficial effect of AFL ablation on AF mechanisms.

Direct-current cardioversion of atrial tachyarrhythmias under oral flecainide therapy.

Results of direct-current cardioversion of 48 patients with atrial arrhythmia taking oral flecainide were compared with those of 96 control-matched patients. After completion of 3 shocks, 98% of flecainide patients were converted versus 78% of control patients (p <0.01). Thus, despite an experimental increase in defibrillation threshold, flecainide given before cardioversion seems to have a beneficial effect.

Progressive ECG changes in arrhythmogenic right ventricular disease. Evidence for an evolving disease.

Electrocardiography results were used to assess diagnosis and evolution of arrhythmogenic right ventricular disease. The initial ECG presentation and long-term changes were analysed in 74 consecutive patients with symptomatic ventricular tachycardia and arrhythmogenic right ventricular disease. On first available tracings, a left axis deviation of the QRS was found in 18 patients. The QRS length in V1 was > or = 110 ms in 39 patients, an epsilon wave was present in 17, and a complete right bundle branch block in four patients. The T wave was negative in V1-V3 in 37 patients (50%). In 36 patients, long-term electrocardiographic follow-up of 9.5 +/- 3.2 years was available. During this period, ECG changes were observed in 20 patients (56%): negative T waves in 11 patients, a new left axis deviation in three, QRS enlargement in 13 (including eight right bundle branch block), right atrial hypertrophy in three, and paroxysmal or established atrial fibrillation in three. On studying all 110 ECG tracings (74 initial recordings +36 follow-up ECGs), we found a strong correlation between QRS or T wave changes and the length of follow-up after the first symptom; mean time interval between first ventricular tachycardia and ECG recording was significantly longer in patients with negative T waves in the right precordial leads, QRS enlargement, or left axis deviation, than in patients without such abnormalities. ECG abnormalities were more frequent at 10 year and 5 year follow-up than on initial tracings. A normal ECG was found in 40% of patients during the first year of follow-up, 8% at 5 years, and never later than the 6th year. In conclusion, electrocardiographic diagnosis of arrhythmogenic right ventricular disease may be difficult in the initial stage of the disease, since a normal ECG is found in up to 40% of patients. During the follow-up, progressive and characteristic ECG changes will occur. Arrhythmogenic right ventricular disease can be excluded if the ECG is found to be normal 6 years or later after a first ventricular tachycardia attack.

Determinants of spontaneous occurrence of sustained monomorphic ventricular tachycardia in right ventricular dysplasia.

OBJECTIVES: We sought to demonstrate the determinants of spontaneous onset of ventricular tachycardia in right ventricular dysplasia. BACKGROUND: Sudden death during athletic activities has been described in patients with right ventricular dysplasia, but few data are available on the clinical circumstances of well tolerated ventricular tachycardias. METHODS: The spontaneous occurrence of 43 episodes of sustained monomorphic ventricular tachycardia was recorded during ambulatory electrocardiographic (Holter) monitoring in 12 patients. RESULTS: The ventricular tachycardia usually occurred without a significant immediate precipitating arrhythmic event: Atrial arrhythmia was never present, and long-short cycle sequences by postextrasystolic pauses or runs of polymorphic extrasystoles were also unusual (four episodes of ventricular tachycardia each). Finally, no arrhythmia was present immediately before the tachycardia in 36 (84%) of the 43 episodes and in 8 of 12 patients. Examination of the sinus rate before the initial episode of tachycardia in each patient showed a continuous increase from 30 min to the few cycles before the tachycardia (mean RR decrease from 876 +/- 778 to 830.5 +/- 189 ms, with a mean slope of approximately 8.4 ms/min; both p = 0.01 by Wilcoxon test). A within-patient comparison showed that the first cycle of the ventricular tachycardia was shorter than that of runs or couplets (389 +/- 88 vs. 453 +/- 121 and 520 +/- 133 ms, p = 0.03 and p < 0.01, respectively, by paired t test) and that the second cycle was shorter than that of runs (383 +/- 96 vs. 435 +/- 120 ms, p = 0.03). Sinus rate measured 15 beats before the event was higher for ventricular tachycardia than for isolated beats (mean RR interval 835 +/- 184 vs. 908 +/- 153 ms, p < 0.01). CONCLUSIONS: Increased heart rate and shortening of the coupling intervals of the first cycles before the tachycardia are due to a change in the vagosympathetic balance with an increased sympathetic tone. This increase appears to be the main determinant of the ventricular tachycardia in this disease in contrast to the multifactorial origin of ventricular tachycardia due to coronary heart disease. It should be considered in patients participating in strenuous athletic activities.

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.

[Value of electrophysiological studies in the evaluation of atrial fibrillation]. / Intérêt de l'exploration électrophysiologique dans l'évaluation de la fibrillation auriculaire.

Electrophysiological studies of the atrium provide a means of evaluating the parameter involved in the process of fibrillation. The study of atrial vulnerability, initially limited to the test of provocation of the arrhythmia, has widened to include analysis of the substrate. Shortened refractory periods and regional conduction defects play a role in the creation of reentry pathways. Variations in the heart rate influence these parameters and explain the fundamental role of the autonomic nervous system on the uniformity of the activation front. The risk of atrial fibrillation is related essentially to thrombo-embolism: atrial vulnerability was investigated in 70 patients with unexplained cerebrovascular accidents. Globally, one out of two patients had pathological substrates. This study of atrial vulnerability showed that it was possible to identify a group of patients at risk of atrial fibrillation, even before the arrhythmia was recorded. This prognostic approach could also be applied to the investigation of preexcitation and syncope, and to the evaluation of the effects of pharmacological intervention.

[Pericardial constriction caused by epicardial patches of automatic implantable defibrillators. Apropos of 3 cases]. / Constriction péricardique due aux patchs épicardiques des défibrillateurs automatiques implantables. A propos de 3 cas.

The authors report three cases of pericardial constriction secondary to implantation of an automatic defibrillator. In one case, the pericardial constriction occurred 1 year after implantation and was associated with ascending infection of the patch electrodes from the stimulator; the patient died when the patch electrodes were removed, the infection having eroded the left ventricular wall. In the other two cases, signs of constriction appeared 2 years after implantation. In one of these patients, surgery showed a fibrous pericardial reaction deforming the patch electrodes with a favourable outcome when the electrodes were removed. The other patient refused surgery. In the three cases, the diagnosis was confirmed by right heart catheterisation and ventriculography which showed signs of adiastole and severe deformation of the ventricular contours. Pericardial constriction due to patch electrodes is a potentially serious complication of implantable automatic defibrillators, the prevalence of which may be underestimated. The use of endocavitary or extra-pericardial electrodes should avoid this complication.