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Resume La cardiologie est un domaine ou la telemedecine devrait connaitre un essor rapide. L’application la plus avancee aujourd’hui est le telesuivi des stimulateurs et defibrillateurs cardiaques implantables, permettant de limiter les suivis en face a face au centre d’implantation et d’acceder plus facilement aux donnees memorisees dans la protheses. Apres une phase de validation technologique, des larges etudes prospectives randomisees (TRUST, CONNECT, COMPAS, ECOST, EVATEL) ont demontre la securite d’utilisation du telesuivi sur des criteres durs de morbi-mortalite avec une valeur ajoutee sous la forme d’une reduction du nombre des consultations, d’une detection anticipee des evenements et d’une reduction des therapies inappropriees. Ce nouveau standard de suivi s’integre parfaitement dans la loi francaise sur la telemedecine. Neanmoins, certains obstacles doivent encore etre leves, notamment les aspects financiers de remboursement des actes pour les equipes medicales et de prise en charge d’un service pour les industriels, avant de passer dans la routine. L’acceptation par les patients et la communaute medicale ne devrait pas etre un reel probleme sous reserve de bien definir les objectifs cliniques et les modalites de partage de l’information. D’autres domaines de la cardiologie devraient a moyen terme s’ouvrir a la telemedecine.

Resume Introduction. – La distensibilite est la capacite des grosses arteres elastiques a faire varier leur diametre de la diastole a la systole. Lˈune des methodes les plus validees pour la mesurer est la velocite de lˈonde de pouls (VOP), qui peut etre mesuree par divers procedes dont le QKd. Exegese. – Le QKd est lˈintervalle de temps compris entre lˈonde Q de lˈelectrocardiogramme et lˈenregistrement du deuxieme bruit de Korotkoff au niveau de lˈartere humerale, correspondant a la tension arterielle diastolique. Il est mesure par un holter tensionnel et electrocardiographique specifique (normale superieure a 200 ms). La distensibilite arterielle semble interessante pour predire les evenements cardiovasculaires. Il a ete montre que les hypertendus âges avec QKd altere font plus dˈevenements cardiovasculaires que les autres. Le QKd est a lˈetude comme predicteur de la progression des sclerodermies (etude ERAMS). Conclusion. – Le QKd est une methode non invasive et ambulatoire qui couple les mesures de distensibilite et de tension arterielle.

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 V 2 through V 4 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 P 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.

Sudden cardiac death frequently results from ventricular fibrillation (VF). While VF is frequently the eventual mode of death in patients with abnormal ventricular substrates, it has also been described in patients with structurally normally hearts. Until recently, the management of patients who have survived sudden cardiac death has focused on treating the consequences by implantation of a defibrillator. However, such therapy remains restricted in many countries, is associated with a prohibitive cost to the community, and may be a cause of significant morbidity in patients with frequent episodes or storms of arrhythmia. Evidence emerging from the study of fibrillation both in the atria and the ventricle suggests an important role for triggers arising from the Purkinje network or the right ventricular outflow tract in the initiation of VF. Initial experience in patients with idiopathic VF and even those with VF associated with abnormal repolarization syndromes (LQT or Brugada syndrome) or myocardial infarction suggests that long term suppression of recurrent VF may be feasible by the elimination of these triggers. With the development of new mapping and ablation technologies, and greater physician experience, catheter ablation of VF, with the ultimate aim of curing such patients at risks of sudden cardiac death, may not be an unrealistic goal in the future.

Since multisite stimulation was first performed in heart failure (HF) [1], a few specific devices have been designed with capabilities for providing separated output control of pacing parameters for the right and left ventricular leads, as well as inter ventricular (VV) sequence programming. So far, there are no haemodynamic sensors to improve understanding of and follow up the effects of biventricular (BiV) stimulation and help in the programming of the resyn-chronisation parameters. In the meantime, Sorin Biomedica has developed the Living-BEST system, which is based on a sensor that is able to measure the amplitude of mechanical vibrations generated by the myocardium during the isovolumetric contraction of ventricles. The peak of endocardial acceleration (PEA) reflects events that produce vibrations that originate mainly in the left ventricle and are transmitted through the cardiac mass [2, 3]. It has been shown that PEA is correlated with contractility indexes, such as dP/dtmax, and is influenced by catecholamine levels. PEA variations are related to the capability of the myocardium to respond to adrenergic stresses. Human experiments [4,5] have shown that PEA variation is greater during exercise with biventricular pacing than compared with to other modes, and it has been suggested that PEA might be used as a marker for selecting the position of ventricular pacing leads that provides the best haemodynamic effect. The version of the Living-BEST system designed specifically for biventricular pacing (Living CHF) has the capability of recording amplitudes and timings of PEA and providing realtime telemetry of the whole endocardial acceleration signal. Secondly, the device has the VV Interval programming feature, which can influence the efficacy of resynchronisation provided by biventricular stimulation. Recent studies [6–13] have been focused on improving understanding of the effects of cardiac resynchronisation therapy. Biventricular stimulation provides a more homogeneous contraction of ventricles, which becomes faster and allows prolongation of the diastolic filling phase. Filling pressures are reduced with the frequent reduction in the mitral valve regurgitation. The most relevant parameter is the aortic pre-ejection interval [14], which has to become shorter to predict the beneficial effect of biventricular stimulation, and also the shortening in the contraction timing of the uncoordinated ventricular segments. In this context the use of a haemodynamic sensor is an interesting possibility as an analytic tool for the evaluation and optimisation of ventricular resynchronisation therapy.

Initial attempts at linear ablation for atrial fibrillation (AF) indicated that creating continuous linear lesions to duplicate surgical atriotomies was difficult, that right atrial lesions alone were safe but ineffective, and that left atrial lesions improved success rates, although at a significant morbidity (including proarrhythmic left atrial reentry) and even mortality cost — but, most importantly perhaps, these studies showed the feasibility of cure by catheter-based techniques in patients with paroxysmal and persistent AF [1–3].

The determining factor in allowing the effective elimination of typical atrial flutter by catheter ablation has clearly been the progressive refinement of procedural endpoints (Table 1). In our own experience, three clear transitions, demarcated by progressive reductions in the recurrence rates for this arrhythmia, have been evident. Beginning with a high recurrence rate when flutter termination and noninducibility were considered sufficient endpoints, the demonstration of cavotricuspid isthmus block based on septal and lateral right atrial activation sequences reduced recurrence rates to about 12%. Further refinement with the routine use of local electrogram-based criteria [1], mapping double potentials supplemented with differential pacing [2], has led to an additional reduction in recurrence rates to < 5%.

Myocardial contractility beat-to-beat evaluation is now possible using an implanted microaccelerometer located on the tip of an endocardial lead in the right ventricle. The signal provided by this device is closely related to right ventricle dp/dt curve. The maximal value of the accelerometer signal, peak of endocardial acceleration (PEA) is correlated with dp/dt max (mm Hg) during dobutamine infusion. Some previous studies have clearly established a direct correlation between right and left ventricle contractility [1–3]. Increased cardiac output during exercise and emotional or psychological stress is mediated by the autonomic nervous system, sympathetic tone increasing myocardial contractility and heart rate [4]. In an individual patient, every PEA value is associated with a heart rate value. These two parameters related by a closed loop algorithm can be used to drive a rate-responsive pacemaker in patients with chronotropic incompetence but normal contractility adaptation during sympathetic stimulation. A DDDR device was provided by Sorin (Italy) Living 1 pacemaker. This works using a specially designed ventricular lead tipped by a microaccelerometer and a standard pacing unipolar electrode. Some studies have demonstrated the efficacy of this pacemaker [5–7]. The aim of this paper is to study the long-term stability of the correlation linking PEA and heart rate variations in implanted patients.

Atrial fibrillation, the most common of all sustained cardiac arrhythmias can be cured by Surgical atriotomies or linear RF catheter ablation. We have investigated the role of focal RF ablation in paroxysmal atrial fibrillation.sixteen patients with focal atrial fibrillation (extrasystoles, atrial tachycardia and atrial fibrillation due to the same focus firing irregularly at different rates) and 45 with common AF initiated by extrasystolic foci were included. The ablation site was determined on the basis of earliest bipolar activity relative to a stable atrial electrogram reference or to the P wave onset during atrial fibrillation initiation.All the patients with focal atrial fibrillation were treated with a mean of 5 +/- 4 RF applications delivered on a right atrial site (n = 4) or on a pulmonary venous site (n = 13), (one patient had 2 foci). Sixty nine foci (located in the pulmonary veins in 94%) were identified in the 45 patients with common atrial fibrillation initiated by extrasystoles. They were ablated with a mean of 4.5 +/- 2 RF applications. Using a mean follow up of 8 +/- 6 months, 28/45 (62%) were cured without antiarrhythmic drugs.Pulmonary veins play an important role in paroxysmal atrial fibrillation. They are the most frequent source of focal atrial fibrillation and of initiating foci amenable to RF ablation.

The aim of this study was to assess the long-term performance of a new dual chamber rate responsive pacing system based on the dynamic measurement of the peak endocardial acceleration (PEA) index of cardiac contractility. Seventy patients who participated in the Multicenter European Clinical Evaluation were studied 1 year after implantation by continuously recording the PEA and the heart rate (HR) during exercise stress testing and during 24 hours of usual activities. A complete examination of standard parameters was also performed to assess the pacing/sensing lead characteristics. Statistical comparisons were performed with the data recorded with the same protocol at 1 month after implant for each patient. A linear correlation coefficient was calculated between PEA and sinus rate when the patient showed predominant atrial tracked rhythm. There were no significant differences between PEA values measured at 1 month and 1 year (PEA = 0.41 +/- 0.26 g vs 0.45 +/- 0.29 g at rest and PEA = 1.63 +/- 0.77 g vs 1.72 +/- 0.83 g during peak exercise). The correlation coefficient remained stable (0.67 +/- 0.15 vs 0.65 +/- 0.14 during daily life and 0.74 +/- 0.14 vs 0.77 +/- 0.11 during exercise). The PEA signal detected by the sensor was reliable and stable. No long-term complications or adverse effects were observed, and the lead performance was comparable to that of a standard lead.

Radiofrequency (RF) catheter ablation is the curative treatment of choice for atrioventricular (AV) nodal reentrant tachycardia (AVNRT). Analogous to the development of surgical techniques, catheter ablation has evolved from AV nodal ablation to selective "fast" and "slow" pathway ablation. "Slow" ablation is now the method of choice because of the lower incidence of associated AV block. Though slow pathway ablation can be achieved with equal success using either the anatomic or the electrogram-guided approach, fewer applications of RF energy are required for the potential-guided technique.

Sixty patients with recurrent inducible sustained ventricular tachycardia were prospectively treated with nadolol (40 or 80 mg/day). Old myocardial infarction was present in 43 patients and dilated cardiomyopathy in 12. In group I (n = 36), nadolol was given alone, whereas in group II (n = 24), previously ineffective treatment with amiodarone was continued in combination with nadolol. Left ventricular ejection fraction was higher in patients in group I (0.40 +/- 0.12) than in group II (0.30 +/- 0.10, p less than 0.01) patients. Electrophysiologic study was repeated after short-term treatment with nadolol, which was continued regardless of the results of this test, according to the scheme of the parallel approach. Recurrence of spontaneous tachycardia or sudden death occurred in 21 patients after 10 +/- 9.2 months; sustained tachycardia was inducible in 19 on nadolol therapy. The remaining 39 patients (of whom 21 had inducible tachycardia while taking the drug) have had no recurrence of tachycardia after 27.8 +/- 9.3 months of follow-up study. Sensitivity, specificity and predictive value of a positive and negative test were 90.5%, 46%, 47.5% and 90%, respectively. The results differ between group I and group II patients, the latter having a high percent of false positive responses. This difference is even more obvious with respect to left ventricular ejection fraction: the predictive value of a positive test was 86% when ejection fraction was greater than 0.40 and 39% when it was less than 0.40.(ABSTRACT TRUNCATED AT 250 WORDS)

The objective of this study was to assess the electrophysiological properties of intravenous bisoprolol in patients with and without coronary artery disease (CAD) by programmed stimulation. Sixteen inpatients subjected to an electrophysiological investigation because of dizziness or palpitations were given 10 mg of intravenous bisoprolol after basal measurement and were checked again 15 and 45 min after infusion. Eight patients with CAD (seven males and one female; mean age of 60+/-4 years) and eight patients without CAD (five males and three females; mean age of 59+/-4 years) were investigated after washout of prior antiarrhythmic drugs. For coronary patients, the CAD was documented by a history of myocardial infarction or by a confirmatory coronary arteriography. Main outcome measures were parameters of invasive electrophysiological exploration, with measurement of conduction intervals at rest and during pacing and of refractory periods by means of extrastimulus technique. No significant difference was noted at baseline between the two groups except for CSNRT. After infusion of 10 mg of bisoprolol, with the exception of CSNRT (increased in the group without CAD), no significant differences were noted on comparison between coronary and noncoronary patients. Bisoprolol significantly increased the sinus cycle length, SACT, and FRP of the atria. Regarding atrioventricular nodal conduction, bisoprolol significantly increased the AH 100, ERP, and FRP and significantly decreased the Wenckebach point. In the right ventricle, bisoprolol moderately, but significantly, decreased the corrected QT and induced a small, temporary, significant increase in ERP. Bisoprolol appears to be a very potent beta-blocker that is well tolerated at an intravenous dose of 10 mg. Its depressant effects concern mainly the atrial function and the nodal conduction, without significant differences between the two groups of patients. The decrease in QTc may be a favorable aspect regarding its electrophysiologic tolerance especially in the acute phase of myocardial infarction.