[Results of the French register of renal stenting: the Esternal study]. / Résultats du registre français du stenting rénal: étude Esternal.

Renal artery angioplasty using the same techniques employed for coronary arteries has developed considerably. A register was set up in France to evaluate the efficacy of this treatment for improving renal function and lowering blood pressure in cardiac patients. Between 2001 and 2005, 205 patients (234 lesions) were treated in 14 centres (mean age: 69.2 +/- 10.4 years, 59% male). All of the patients had hypertension and the majority of them (171) had renal failure (creatinine clearance<90 ml/min). Direct implantation of a stent was performed in 75.2% of the cases, successfully in 196 patients (96%) with 220 lesions (95.2%). The complications encountered were segmental renal infarction in two patients (0.9%), and four cases of minor vascular complications at the puncture site (2%). The mean value for pre-implantation creatinine clearance was 54.6 +/- 32.8 ml/min and 58.1 +/- 36.0 post- implantations. The duration of follow up was 5.9 +/- 2.7 months. Mortality was 3.5% (seven patients, of whom two died from renal causes). The mean systolic and diastolic blood pressure was 142.2 +/- 16.2 and 78.9 +/- 9.5 respectively versus 164.9 +/- 25.2 and 89.1 +/- 14.8 before treatment (p<0.0001). A non-significant improvement in creatinine clearance at six months was also observed in patients with renal failure prior to treatment: 48.7 +/- 17.1 ml/min vs. 69.2 +/- 160.3. Renal artery stenting in cardiac patients with renal artery stenosis is associated with a very high success rate, with few complications and an improvement in hypertension and renal function.

Improved detection and analysis of sensed and paced events in dual chamber pacemakers with extended memory function. A prospective multicenter trial in 626 patients.

PATIENTS AND METHODS: This prospective study analyzed the incidence of atrial arrhythmias in a population of 626 patients in 173 medical centers of eleven European countries and Japan with indication for a dual chamber pacemaker system. The accuracy of the new Automatic Interpretation for Diagnosis Assistance (AIDA) program which is included in Chorus pacemakers was evaluated and the AIDA analysis was compared to and proven with Holter monitoring. Data stored in the pacemakers' memories for the first 24 hours (D1) were compared with simultaneously recorded 24-hour surface electrocardiograms, and data stored over the following 28 days (D28) were examined against reported intercurrent symptoms. RESULTS: At D1, atrial arrhythmias were detected by AIDA in 60 of 626 patients (12%), consisting of atrial fibrillation (n = 29), atrial flutter (n = 4), and miscellaneous arrhythmias (n = 17), and closely corroborated by Holter monitoring (sensitivity 93.7%, specificity 94.9%). At D28, 149 of 386 patients (49%) had had episodes of automatic mode switch prompted by atrial arrhythmias. Symptoms were reported by 81 patients (54%), 92 (62%) had no histories of atrial arrhythmias, and 57 patients (38%) were neither symptomatic nor had histories of atrial arrhythmias. An inverse relationship was found between the number of atrial paced events and the occurrence of atrial arrhythmias (p < 0.001). A history of atrial arrhythmias and older age were associated with a higher risk of atrial arrhythmias (p < 0.05). In contrast, gender, hypertension, concomitant heart disease, or type of atrial lead fixation system were not related with the occurrence of atrial arrhythmias. CONCLUSION: AIDA allowed to confirm, or disprove, the occurrence of atrial arrhythmias as a source of symptoms reported during long-term follow-up. It could also be used to examine the efficacy of antiarrhythmic therapy, and be of assistance when weighing the needs for anticoagulation in patients experiencing asymptomatic atrial arrhythmias.

[A new diagnostic concept in cardiac pacing for the evaluation of the incidence of atrial arrhythmias. Results of the AIDA study]. / Un nouveau concept diagnostique en stimulation cardiaque pour évaluer l'incidence des arythmies atriales. Résultats de l'étude AIDA.

An international, prospective, multicentre trial (AIDA) was undertaken from October 1995 to March 1997. The object was to compare the diagnosis of atrial arrhythmias (AA) by the automatic interpretation of the memory functions of dual chamber pacemakers with that of 24 hour Holter monitoring at day 1. The second objective was to assess the incidence and symptomatology of the AA during follow-up at Day 28. In France, 226 patients implanted with Chorus, Chorus II and Chorus RM pacemakers were included in the study (148 men, 70.5 +/- 10.8 years) for the following indications: AVB (atrioventricular block)/bundle branch block (47.3%), sinus mode dysfunction (10.2%), bradycardia-tachycardia syndrome (10.2%), AVB + sinus node dysfunction + cardia-tachycardia syndrome (19.5%), other (2.2%). AA were documented in 34.5% of patients before implantation. Of the 226 patients analysed at Day 1, 23 (10.2%) had at least one episode of AA diagnosed simultaneously by Holter monitoring and the automatic interpretation (AIDA). These AA were atrial fibrillation (15 patients), atrial flutter (2 patients) and atrial tachycardia (6 patients). The sensitivity of the AIDA programme for detecting AA was 92% and the specificity 97%. Of the 156 patients evaluated at Day 28, the programme diagnosed AA in 78 patients (50%), 34 of which (21.8%) were asymptomatic and without previously documented AA. The results of the AIDA study confirmed the excellent sensitivity and specificity of the memory functions of these cardiac pacemakers for analysis of AA. They seem to be very common during the follow-up of pacemaker-equipped patients. This new diagnostic concept will facilitate the programming and study of the efficacy of anti-arrhythmic therapy prescribed during long-term follow-up.

Prevalence of supraventricular arrhythmias from the automated analysis of data stored in the DDD pacemakers of 617 patients: the AIDA study. The AIDA Multicenter Study Group. Automatic Interpretation for Diagnosis Assistance.

The confirmation of the occurrence of supraventricular arrhythmias (SVAs) is possible only if a surface electrocardiogram (ECG) is recorded during an episode, or if SVAs occur during 24 h ambulatory monitoring (Holter). The automatic interpretation of memory functions in DDD pacemakers may be useful in this diagnostic task over longer periods of follow up. This hypothesis was tested in 384 men and 233 women (mean age = 70 +/- 11 years) who had received Chorus 6034/6035, 6234 or 7034 pacemakers (ELA Medical, Montrouge, France) with fall-back function in case of sustained SVAs. The Automatic Interpretation for Diagnostic Assistance (AIDA) algorithm included in these pacemakers was compared with 24 h Holters recorded simultaneously (D1) and with the clinical history of symptoms consistent with SVAs up to 28 days of follow up (D28). Indications for pacing were atrioventricular block (AVB) in 269 patients, sinus node dysfunction (SND) in 248, and AVB + SND in 100. SVAs were documented before implant in 199 patients (32%). Among the 617 patients included at D1, 76 (12.4%) developed at least one SVA episode, lasting between 1 min and 24 hours, simultaneously recorded on Holter and by AIDA with a 93.8% sensitivity and 94.2% specificity. Data from 354 patients were available for analysis at D28. AIDA diagnosed SVAs in 179 patients (50.6%), 104 of whom (65%) had remained asymptomatic and 117 of whom (65%) had had no SVA documented before implant. Among the 354 patients, AIDA diagnosed SVAs in 76 (21%) asymptomatic patients who had no known SVA before implant. The prevalence of SVA in our AVB population was higher than reported in previous studies: 89 patients (56.3%) with AVB had SVAs versus 90 patients (45.9%) with other diagnoses (p = 0.55). Furthermore atrial pacing was associated with fewer SVAs. These first clinical results of the AIDA study demonstrate that the memory functions of Chorus pacemakers and the AIDA software are reliable to analyze the prevalence of SVA at 1 month of follow-up. From a clinical point of view, AIDA is a valuable tool to evaluate the efficacy of antiarrhythmic therapy, particularly as it pertains to the prevention of stroke due to atrial fibrillation.

Additive effects of acetylcholine released by vagal nerve stimulation on atrial rate.

In reserpinized dogs, the decrease in atrial rate (AR) as a function of the frequency of stimulation (supramaximal strength) of a single vagal nerve can be described satisfactorily by a rectangular hyperbola (RH). If the RH of one vagal nerve has been determined and if one point of the RH of the other vagal nerve is known, then the latter RH can be determined. Both RHs being known and assuming that the acetylcholine released by the right and left vagal nerves is additive, the slowing of AR by simultaneous stimulation of both nerves can be predicted. A minor systematic deviation from the predicted AR during simultaneous stimulation is usually found, which could be accounted for by a time dependent decrease of the effect of vagal nerve stimulation. The results are qualitatively similar during norepinephrine infusion. We propose that, although the vagal innervation may vary from pacemaker cell to pacemaker cell, the ratio of the activities of the two vagal nerves is constant throughout the sinoatrial node.