Patrick Attuel

Failure in the rate adaptation of the atrial refractory period: its relationship to vulnerability.

We evaluated the relationship of rate-dependent changes in atrial refractoriness to atrial vulnerability in 39 patients. Vulnerability was considered present when sustained atrial tachyarrhythmias, lasting longer than 1 minute, could be provoked with one to three extra stimuli. Adaptation of atrial refractory period duration to rate was defined as: normal: steep rate reduction with a linear correlation slope value of 0.08 or more; non-adaptation: absence of rate reduction, the slope value being 0 to 0.01; poor adaptation: slight reduction with rate, the slope having values of 0.02 to 0.07. Increased vulnerability was demonstrable in 16 of 17 patients with non-adaptation of the effective refractory period (ERP), and in 10 of 10 with a similar defect of the functional refractory period (FRP); in the intermediate category (poor adaptation) the results for ERP and FRP were 7/11 and 5/6. By way of contrast when both measurements showed normal adaptation, vulnerability was elicited in 2/9 patients. The significance between these groups showed P less than 0.005. Of 17 patients with atrial arrhythmia by Holter, 14 showed poor or non-adaptation of the ERP. It is suggested that poor or absent rate adaptation of the atrial refractory period, and a propensity to atrial fibrillation or flutter, constitute a clinical entity not previously described.

Long‐term Prevention of Vagal Atrial Arrhythmias by Atrial Pacing at 90/Minute: Experience with 6 Cases

Six patients (5 men, 1 woman) with a history ranging from 3–16 years of resistant vagal atrial arrhythmias were treated by atrial pacing at a rate of 90Jmin. These patients have been followed up for an average of 5.5 years (range 2–11 years) with favorable resutls. The arrhythmias were charactemed by daily or weekly attacks of rypical alrial flutter and atrial fibrillalion occurring mainly or exclusively at night, at rest, or in the digestive periods in otherwise normal hearts of middle‐aged palients (first attack between 25 and 54, mean 40). The arrhythmias werc resistant to quinidinc, and were usually aggravated by digitalis, beta‐blockers and verapamil. Amiodaroneisusually the only effective drug in this syndrome, but was not used before pacing in the 2 first cases, and was in effective in the other 4 cases. Electrophysiologic studies confirmed the absence of sick sinus syndrome, and the close relationship betwecn a relative bradycardia and the onset of the arrhythmia. Atrial pacing alone totally controiled the arrhythmia in 1 palient; amiodarone was used in conjunction with pacing in 3 palients. In 1 patient the improvement was clear but incomplete, and in 1 patient permanent alrial fibrillation occurred shortly afler pacemaker implantalion.

Optimized post-operative surveillance of permanent pacemakers by home monitoring: the OEDIPE trial.

Aims The ŒDIPE trial examined the safety and efficacy of an abbreviated hospitalization after implantation or replacement of dual-chamber pacemakers (PM) using a telecardiology-based ambulatory surveillance programme. Methods and results Patients were randomly assigned to (i) an active group, discharged from the hospital 24 h after a first PM implant or 4–6 h after replacement, and followed for 4 weeks with Home-Monitoring (HM), or (ii) a control group followed for 4 weeks according to usual medical practices. The primary objective was to confirm that the proportion of patients who experienced one or more major adverse events (MAE) was not higher in the active than in the control group. The study included 379 patients. At least one treatment-related MAE was observed in 9.2% of patients (n = 17) assigned to the active group vs. 13.3% of patients (n = 26) in the control group (P = 0.21), a 4.1% absolute risk reduction (95% CI −2.2 to 10.4; P = 0.98). By study design, the mean hospitalization duration was 34% shorter in the active than in the control group (P < 0.001), and HM facilitated the early detection of technical issues and detectable clinical anomalies. Conclusion Early discharge with HM after PM implantation or replacement was safe and facilitated the monitoring of patients in the month following the procedure.

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‐sits 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 ≥ 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 ≥ 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 ≥ 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.

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

Electrophysiologic Characteristics in Sinus Node Dysfunction. 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.

Long-Term Follow-up of Atrioventricular Junctional Transcatheter Electrical Ablation

Complete data concerning long‐term results of transcatheter electrical ablation of the atrioventricular junction is not available. At the request of the French Cardiac Arrhythmia Working group we undertook an inquiry in October 1983. All centers potentially able to perform such procedures were asked to report their experience. Eight centers have performed one case or more, over a period of 3 years, for a total of 91 patients. The mean follow‐up completed in all patients in April 1986 was 12 ± 10 months. The procedure was indicated for a supraventicular arrhythmia resistant to a mean of 3.9 ± 1.3 classes of antiarrhythmic agents. Atrial flutter or fibrillation in 54 (59%) and atrioventricular nodal reentry in 17 (18%J were the most common arrhythmias. A mean of 2.6 ± 2.3 electrical shocks (range 1–14 shocks) with a stored energy of 130–400 joules was delivered during 1–5 sessions. Complete heart block was obtained in 83 patients and persisted at the time of discharge from the hospital in 46 patients (50.5%). The immediate complication (within 24 hours after the procedure) included ventricular fibrillation successfully converted (one patient) and nonsustained ventricular tachycardia (three patients). Late complications included one death 3 days after the procedure, in a patient in whom sustained ventricular tachycardia was documented, nonsustained ventricular tachycardia in two patients, sepsis in three patients and pericardial effusion in one patient. At the time of the follow‐up, there were three additional deaths related to sepsis due to pacemaker pocket infection in one patient and to preexisting congestive heart failure in two patients. Chronic complete heart block was present in 36 patients (41%) high degree heart block (2 nd degree or advanced) in seven patients (8%) first degree in 16 patients (18%). The remaining patients had either normal PR interval or were in atrial fibrillation. Seventy‐five patients (82%) were asymptomatic including 39 patients with resumption of AV conduction with (28 patients, 30%) or without (11 patients, 12%) antiarrhythmic therapy. The procedure failed in 12 patients (13%). This experience suggests that AV junctional transcatheter ablation is a highly effective procedure. However, the potential of early and late complications including arrhythmic death leads us to reserve this technique to patients with drug‐refractory supraventricular tachyarrhythmias and in whom other forms of therapy are not applicable.

P Wave Duration and Morphology Predict Atrial Fibrillation Recurrence in Patients with Sinus Node Dysfunction and Atrial-Based Pacemaker

DE SISTI, A., et al.: P Wave Duration and Morphology Predict Atrial Fibrillation Recurrence in Patients with Sinus Node Dysfunction and Atrial‐Based Pacemaker. P wave duration and morphology have never been systematically evaluated as markers of AF in patients with a conventional indication to pacing. This study correlated sinus P wave duration and morphology and the incidence of AF in patients with sinus node dysfunction (SND), previous history of AF before implant, and atrial‐based pacemaker. Included were 140 patients (86 men, 54 women; mean age 71.8 ± 10.4 years) with recurrent paroxysmal AF and who received a DDD (128 patients) or AAI (12 patients) pacemaker for SND. Forty‐nine patients had structural heart disease. Sinus P wave duration and morphology was evaluated in leads II, III. Twenty‐two patients had an abnormal P wave morphology, diphasic (+/‐) in 5 and notched (+/+) in 17. The basic pacemaker rate was programmed between 60 and 70 beats/min. Rate responsive function was activated in 65 patients. During a follow‐up of 27.6 ± 17.8 months, AF was documented in 87 patients. Forty‐four patients developed permanent AF, following at least one episode of paroxysmal AF in 26 cases. Statistical analysis used Cox model regression. Univariate predictors of AF (P < 0.10) were drugs (mean: 2 ± 1.4) and DC shock before pacing (16/140 patients), P wave duration (mean 112.5 ± 24.6 ms), basic pacemaker rate (mean 68 ± 5 beats/min), and drugs in the follow‐up (mean 1.2 ± 0.94). Multivariate analysis showed that P wave duration (b = 0.013, s.e. = 0.004; P = 0.003), and drugs before pacing (b = 0.2; s.e.= 0.08; P < 0.01) resulted in a significant independent predictor of AF. Actuarial incidence of patients free of AF at 30 months was 35%: 56% in patients with a P wave < 120 ms, and 13% in those with P wave ≥ 120 ms (P < 0.01 by Score test). Univariate predictors of permanent AF were drugs and DC shock before pacing, left atrial size (mean 39 ± 6 mm), P wave duration, abnormal P wave morphology (22/140 patients), and drugs in the follow‐up. Multivariate analysis showed that P wave morphology was the most important predictor of permanent AF (b = ‐ 0.56, s.e.= 0.2; P = 0.008). Incidence of patients free of permanent AF at 30 months was 69%: 74% in patients with normal P wave, compared to 28% in the case of abnormal P wave morphology (P < 0.01). P wave duration and morphology are good markers of postpacing AF recurrence in patients with SND and an atrial‐based pacemaker. This observation suggests that intra‐ and interatrial conduction disturbances be extensively evaluated before implantation, and the indication for atrial resynchronization procedures be reevaluated.

Electrophysiologicai Characteristics of the Atrium in Sinus Node Dysfunction With and Without Postpacing Atrial Fihriliation

. 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 electrophysioiogicai (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 FP 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), Sl‐Al and S2‐A2 latency, Al and A2 conduction duration, and latent vulnerability index (EHP/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/Vl 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 Sl‐Al (39 ± 16 vs 33 ± 11 ms) and S2‐A2 latency (69 ± 24 vs 63 ± 25 ms). In contrast, we observed significant differences regarding Al (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. Sl‐Al, S2‐A2, Al duration, or follow‐up duration. In patients with postpacing AF occurrence, A2 was longer (116 ± 41 vs 87 ± 27 ms; P < 0.01), FRP/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. sinus node dysfunction, atrial fibrillation, electrophysiologicai study, atrial pacing

The Role of the Conduction System in Supraventricular Tachycardias

Unequivocal proof of the reciprocating mechanism of ectopic tachycardias is difficult to obtain if the criteria of initiation and termination by appropriate electrical stimulations are not considered as perfectly reliable. Localizing precisely the pathways of conduction which are involved by the re-entrant impulse, or at least the macroscopic size of the reentry circuit is the best way to rule out both automatic focus and micro-re-entry. The methods used are exemplified in ten cases of supraventricular tachycardia. In two cases the circus movement is intra-atrial, and in one of them it is possible to evidence the macroscopic size of a sinus node re-entry circuit. In A-V junctional tachycardias, localizing precisely the lower junction of the circuit shows that strictly intra-nodal longitudinal dissociation is rarer than usually admitted. Either longitudinal dissociation of the His bundle itself, or the presence of latent accessory pathways (James fibers, Kent bundle and Mahaim fibers) might be more frequent than realized. An exceptional case is reported, where the A-V nodal-His axis does not participate in the re-entry circuit, but two Kent bundles exist, one of them being latent.

Clinical Experience with 910 Carbon Tip Leads: Comparison with Polished Platinum Leads

Since 1980, we have implanted 910 carbon tip leads from three different manufacturers. The pacing thresholds from these leads were compared to those of standard polished platinum electrode configurations. Our major findings are that while acute voltage thresholds are not significantly different, two of the three carbon tip leads that we used in the study have statistically lower chronic thresholds then polished platinum leads (p ≤ 0.01).