[Senegal's experience with pacemakers re-use : about 161 patients at the Aristide Le Dantec university hospital center]. / Expérience du Sénégal sur les pacemakers reconditionnés : à propos de 161 patients au centre hospitalo-universitaire Aristide Le Dantec.

INTRODUCTION: The reuse pacemakers is a beneficial technique for patients in countries with a low economic standard of living where health care is almost non-existent. We offered to share the experience of Senegal on the reconditioning of pacemakers. METHODOLOGY: We conducted a retrospective study over a period from January 2015 to December 2020 including all patients who benefited from a reconditioned pacemaker for primary implantation or reimplantation. The criteria for reconditioning pacemakers are the absence of dysfunction or damage and a residual battery life of more than 5 years of the pacemaker. Refurbished pacemakers are acquired either from deceased families or from extraction centers. Sterilization is carried out using phenoxypropanol + benzalkonium chloride solution, 70% ethanol and ethylene oxide. RESULTS: We collected 161 patients during the study period, including 77 men (48%) and 84 women (52%), i.e. a M/F sex ratio of 0.94. The average age of the population was 65 years. Functional symptomatology was dominated by syncope in 54%. Electrocardiographically, 72% of patients were in complete atrioventricular block. A primary implantation was noted in 91.5% of patients. The vascular approach most used during implantation was cephalic in 49.5% of cases. In our series, we noted that 58% of patients had benefited from temporary stimulation before implantation. At implantation, single-chamber stimulation was used in 60% of patients and 46.5% of patients had programming in VVI mode. We had 5.5% major complications with 3% box infection occurring between 3 and 6 months post-implantation and 2.5% pacemaker syndrome. We noted 1 case of death linked to underlying heart disease. CONCLUSION: Reconditioning of cardiac pacemakers is a safe and beneficial therapeutic strategy for patients. In Senegal, reconditioning has shown satisfactory results. In our countries this technique can be an alternative for certain patients.

A new gastric impedancemeter for detecting the development of a visceral edema: a proof-of-concept study on an experimental endotoxemic shock.

Visceral congestion and edema are important features of advanced heart failure. Monitoring the evolution of fluid content in the gastric wall might provide an index of the development of this phenomenon and therefore constitute an innovative marker to early detect acute decompensated heart failure episodes. The evolution of the fluid content in the gastric wall is measured using a device implanted in the submucosa layer of the fundic region of the stomach. The device composed of two electrodes measures the bioimpedance values that reflects the water content of the tissue.An in-vivo experiment in a pig was carried out to validate the feasibility of detecting the gastric bioimpedance variations during the development of an experimental acute visceral edema caused by an endotoxemic shock. Our preliminary results confirm the possibility to monitor the bioimpedance variations due to moderate changes in tissue water content (10%) with a two-electrode configuration device implanted in the submucosa of the stomach.

Accuracy of the pacemaker-mediated tachycardia algorithm in Boston Scientific devices.

INTRODUCTION: The incidence of pacemaker-mediated tachycardia (PMT) varies as a function of patient characteristics, device programming and algorithm specificities. We investigated the efficacy of the Boston Scientific algorithm by reviewing PMT episodes in a large device population. METHODS: In this multicenter study, we included 328 patients implanted with a Boston Scientific device: 157 non-dependent patients with RYTHMIQ™ activated (RYTHMIQ group), 76 patients with permanent AV-conduction disorder (AV-block group) and 95 Cardiac Resynchronization Therapy patients (CRT group). For each patient, we reviewed the last 10 remote monitoring-transmitted EGMs diagnosed as PMT. RESULTS: We analyzed 784 PMT episodes across 118 patients. In the RYTHMIQ group, the diagnosis of PMT was correct in most episodes (80%) of which 69% was directly related to the prolongation of the AV-delay associated with the RYTHMIQ algorithm. The usual triggers for PMT were also observed (PVC 16%, PAC 9%). The remainder of the episodes (20%) in RYTHMIQ patients and most episodes of AV-block (66%) and CRT patients (74%) were incorrectly diagnosed as PMT during sinus tachycardia at the maximal tracking rate. The inappropriate intervention of the algorithm during exercise causes non-conducted P-waves, loss of CRT (sustained in six patients) and may have been pro-arrhythmogenic in one patient (induction of ventricular tachycardia). CONCLUSION: Algorithms to minimize ventricular pacing can occasionally have unintended consequences such as PMT. The PMT algorithm in Boston Scientific devices is associated with a high rate of incorrect PMT diagnosis during exercise resulting in inappropriate therapy with non-conducted P-waves, loss of CRT and limited risk of pro-arrhythmic events.

[Malignant fascicular ventricular tachycardia degenerating into ventricular fibrillation in a patient with early repolarization syndrome]. / Une tachycardie ventriculaire (TV) fasciculaire maligne dégénérant en fibrillation ventriculaire (FV) associée à un syndrome de repolarisation précoce.

A 45-year-old man was hospitalized for syncope due to fascicular ventricular tachycardia degenerating into ventricular fibrillation (VF). The electrocardiogram showed an early repolarization syndrome. The arrhythmia was repetitive and disappeared after oral hydroquinidine. An implantable cardioverter-defibrillator (ICD) was implanted; subsequently, the patient was arrhythmia free at 9 months follow-up.

[Transcatheter cryoablation of tachycardia: principles and indications]. / Cryoablation par cathéter des tachycardies: principes et indications.

Cryoablation is used for definitive treatment of arrhythmias by catheter after a 4 min application of a -70 degrees C temperature. There are three main indications of this technique: (1) the treatment for intranodal tachycardia is commonly performed using cryoablation. Success rates are high with no atrio-ventricular block (AVB) risk, (2) the ablation of atrioventricular accessory pathways (Wolf Parkinson-White syndrome), close to His-bundle has a high success rate; the use of a cryo focal catheter avoid AVB risk, (3) the ablation of pulmonary vein potentials with a cryo-balloon in the left atrium for atrial fibrillation. The success rate is high, similar to that achieved with radiofrequency ablation. The cryoballoon procedure is easier to perform because ablation is done in a single step, with a circular application and not point by point. It is well tolerated because it is less painful. There is no risk of pulmonary vein stenosis or esophagus injury. It is less thrombogenic.

[Significance of the contralateral approach combined with venous deocclusion in a case of biventricular defibrillator implantation]. / Intérêt de l'abord controlatéral associé à une désobstruction veineuse en cas d'implantation d'un défibrillateur biventriculaire.

The authors report the case of a patient in whom a biventricular defibrillator was successfully implanted from the right, following a failed approach from the left. The patient had chronic thrombosis of the subclavian vein, and this procedure was only possible after venous deocclusion and the positioning of an endoprosthesis. The authors underline the significance of the contralateral approach in case of difficulties in inserting pacing devices, as well as the complementary benefits of interventional radiological procedures in order to allow vascular access in cases of chronic venous thrombosis.

[Pacemaker and intra cardiac defibrillator lead extraction techniques]. / Les techniques de remplacement de matériel de stimulation cardiaque et défibrillation implantable.

Percutaneous Pace-maker and ICD lead extraction techniques has been developped: by superior approach using locking stylet and more and more efficient outher sheats (laser assisted); and also by femoral approach using double lasso catheters (Needle's eye snare). Indication range has increased and is not only reserved for lead infection. Because of scar tissue holding the lead and also the impact of the distal tip, those techniques are not simples. Extraction recommandations do advise those procedures to be performed by expert physicians, in cardiac surgery centers, where complications can be managed and reduced. The use of laser assisted outher sheats will make lead extraction easier and will reduce complication rate. Alternative procedure in case of failure with superior approach remain femoral approach. All those techniques give a success rate of about 98 % for percutaneous lead extraction in an expert center.

Overdrive atrial pacing does not improve obstructive sleep apnoea syndrome.

The aim of this study was to assess the ability of overdrive atrial pacing to reduce sleep apnoea severity. A total of 17 unselected patients (12 males; mean+/-SD age 71+/-10 yrs; body mass index 27+/-3 kg x m(-2)) who had received permanent atrial-synchronous ventricular pacemakers for symptomatic bradyarrhythmias and not known to have central or obstructive sleep apnoea syndrome (OSAS) were studied. Using a crossover study design, patients were or were not in pacing mode with atrial overdrive (15 beats x min(-1) faster than mean baseline nocturnal cardiac frequency) for 1 month. Patients were paced only during sleep periods, identified by a specific algorithm included in the pacemaker. Patients underwent three overnight polysomnographic evaluations 1 month apart. The first was performed for baseline evaluation. The patients were then randomly assigned to either 1 night in spontaneous rhythm or to 1 night in pacing mode with atrial overdrive. Two patients refused to continue the study after the first polysomnographic evaluation. OSAS was highly prevalent in this population: 10 of the 15 (67%) patients exhibited an apnoea-hypopnoea index of >30 events x h(-1). The nocturnal spontaneous rhythm was 59+/-7 beats x min(-1) at baseline, compared to 75+/-10 beats x min(-1) with atrial overdrive pacing. The apnoea-hypopnoea index was 46+/-29 events x h(-1) in spontaneous rhythm, compared to 50+/-24 events x h(-1) with atrial overdrive pacing. Overdrive pacing changed none of the respiratory indices, or sleep fragmentation or sleep structure parameters. In conclusion, atrial overdrive pacing has no significant effect on obstructive sleep apnoea.

[Value of memory functions in implantable prostheses]. / Apport des mémoires embarquées dans les prothèses implantables.

The development of memory functions with memorised electrogrammes is one of the most important technical advances in cardiac pacemakers and defibrillators. These memory functions are very useful in the management of patients with implanted prostheses. In the case of defibrillators, the memory allows evaluation and validation of appropriate treatments (shock or asymptomatic antitachycardia stimulation) or inappropriate function. The memory can also help assess the efficacy of complementary antiarrhythmic therapy or radiofrequency ablation. The incorporation of memory functions in pacemakers is more recent but no less useful. The latest generation of pacemakers have not only a therapeutic but also a diagnostic role with respect to atrial and ventricular arrhythmias. They can lead to the prescription of an antiarrhythmic or anticoagulant drug in cases of sustained atrial fibrillation confirmed by the memorised electrogrammes. The memory function is also a great aid in reprogramming stimulators in cases of overdetection (V-A cross talk). They may also be activated by the patient in cases of sporadic paroxysmal symptoms. The latest development is that of a purely diagnostic prosthesis: the implantable Holter, whose main indication is in the investigation of unexplained syncope.

[Role of atrial stimulation in the treatment of paroxysmal atrial fibrillation]. / Place de la stimulation auriculaire dans le traitement de la fibrillation auriculaire paroxystique.

Preventive treatments for atrial fibrillation by stimulation have been developed for several years now, mainly due to the relative failure of anti-arrhythmic treatments. They are based on the hypothetical effects of stimulation by controlling cardiac frequency, abolishing bradycardia-dependent extrasystoles, by the inhibition of atrial automatic foci with "overdrive", and by the modification of intra- or inter-atrial conduction delays as well as by remodelling the arrhythmogenic substrate. It is clear that an undeniable effect exists for the prevention of atrial fibrillation, even for the risk of cerebral vascular accident, by physiological stimulation (DDD/DDDR) compared to pure ventricular stimulation (VVI/VVIR) in a heterogenous global population of stimulated patients. For the moment, there is not sufficient proof of a positive effect for the emerging sites of cardiac stimulation, either atrial mono-site or double site in the populations at high risk of atrial fibrillation, with or without associated bradycardia. Some new prevention algorithms by "overdrive" are under development but for the moment only a few preliminary studies seem to show a slight benefit. It is clear that at present stimulation should be reserved only for cases of atrial fibrillation associated with a classic indication for implantation. In these patients it is recommended to position the probes in an optimal manner in order to counteract conduction disorders, choosing an adapted double chamber stimulator with prevention algorithms. That said, the patient should be clearly warned that the long term success rate is no more than 50%.

[Atrial flutter: a possible early sign of acute rejection in heart transplantation. A case report]. / Le flutter atrial: un témoin précoce possible du rejet aigu chez le transplanté cardiaque. A propos d'une observation.

The authors report the case of a cardiac transplant patient with a recurrence of atrial flutter two months after electrical cardioversion and despite long-term preventive treatment with amiodarone. Early investigation for signs of rejection with 4 endomyocardial biopsies was negative. Aggravation of the haemodynamic status due to flutter with a rapid ventricular response led to an attempted radio-frequency ablation. Endocavitary mapping confirmed persistence of sinus activity in the native atrium and the presence of a circuit of type I isthmic flutter (anticlockwise circuit) in the donor atrium. Ablation by radio-frequency in the same procedure was successful. A fifth myocardial biopsy the same day finally confirmed stage 3A acute rejection. No signs of recurrent rejection or arrhythmia have been observed after 24 months' follow-up in this patient. This preliminary experience confirms the need to look for graft rejection by repeated myocardial biopsies in cardiac transplant, patients with atrial flutter and the efficacy of radio-frequency ablation in cases of resistance to conventional therapy.

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.

[Ventricular tachycardia by branch to branch re-entry. Familial case with Steinert's disease]. / Tachycardie ventriculaire par réentrée de branche à branche. Cas familial avec maladie de Steinert.

Ventricular tachycardia by branch to branch reentry is a rare arrhythmia. It occurs in cardiomyopathies associated with conduction defects. During tachycardia a His potential precedes each QRS complex which usually has a left bundle branch block appearance. The authors report two familial cases of ventricular branch to branch tachycardia (son and mother) without cardiomyopathy. The diagnosis of Steinert's disease was made post-mortem in these two patients. In cases of branch to branch ventricular tachycardia, the diagnosis of myotonic dystrophy should be excluded. Conversely, endocavitary electrophysiological investigation with ventricular stimulation should be proposed for symptomatic patients (dizzy spells, syncope) to diagnose branch to branch ventricular tachycardia, even in cases with conduction defects which could also explain the symptoms.

Near fatal electrical storm in a patient equipped with an implantable cardioverter defibrillator for Brugada syndrome.

A patient with Brugada syndrome experienced incessant ventricular fibrillation 7 years after implantation of an ICD. General anesthesia, fast ventricular pacing, bretylium, and atenolol infusion were ineffective; amiodarone infusion was started. After 190 defibrillation shocks over 36 hours, the electrical storm stopped. A multiorgan failure occurred as a complication of the electrical storm and necessitated prolonged reanimation. Thorough cardiac evaluation revealed no structural abnormality and the patient, now on chronic oral amiodarone therapy, remains free of arrhythmia 1 year after the event.

[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.