Anti-arrhythmic effects of I (Na), I (Kr), and combined I (Kr)-I (CaL) blockade in an experimental model of acute stretch-related atrial fibrillation.

INTRODUCTION: Atrial dilatation is commonly associated with atrial fibrillation (AF), but the electrophysiological mechanisms and the implications for anti-arrhythmic therapy are poorly understood. In a model of acute stretch-related AF in isolated rabbit hearts, we evaluated the electrophysiological effects of three different anti-arrhythmic drugs: dofetilide, flecainide and BRL-32872 (associating I (Kr) and I (CaL) blocking properties). METHODS: After 30 min of sustained stretch-related AF, we perfused BRL 10-7 M, BRL 3.10-7 M, BRL 10-6 M, flecainide 2.4 10-6 M and dofetilide 10-7 M and iteratively measured atrial effective refractory periods (ERPs), AF inducibility and AF cycle length (AFCL) 15, 30 and 60 min after drug perfusion, respectively. RESULTS: After a significant shortening of the ERPs by acute atrial stretch in the five groups individually (p < 0.001, stretch vs baseline for each group individually), drug perfusion led to a strong lengthening of AFCL, a very significant prolongation of ERPs (p < 0.001 vs stretch) and a reduction of AF inducibility (p < 0.01 vs control group) for each of the five experimental groups. The relative ERP increase was comparable in all groups, whereas a significantly lower AF inducibility was observed in the BRL 10-6 M group (p < 0.05 vs other BRL concentrations). CONCLUSION: In a model of acute stretch-related AF, dofetilide, flecainide and BRL-32872 terminated AF and prevented its immediate reinduction after having comparatively prolonged AFCL and ERPs. These comparative results suggest that those drugs are equally efficacious, albeit with different mechanisms, in the setting of acute atrial stretch.

Diagnosis of Coxiella burnetii pericarditis using a systematic prescription kit in case of pericardial effusion.

Coxiella burnetii, regarded as a potential agent of pericarditis, wa found to be responsible for almost 5% of the cases of idiopathic pericardial effusion reported in this series. Diagnosis was aided by use of a systematic kit described in this paper.

Home Monitoring: what can we expect in the future?

The Home Monitoring of implanted cardiac rhythm management devices developed by Biotronik (Berlin, Germany) is a new useful tool for monitoring patients. Home Monitoring provides access to technical and clinical data, allowing almost continuous patient surveillance. The implanted defibrillators and pacemakers transmit encrypted messages, which are automatically analyzed in the Home Monitoring Service Center and sent to the physician. The expected benefit of this kind of data transmission is an improvement in patient follow-up and early detection of changes in the rhythmologic state of the patient. However, these new tools raise several questions, which will require an answer in the nearest future. These questions focus on safety and economic aspects, and on the liability of the physician and the manufacturer. Technological improvement is also expected.

[Modern management of vasovagal syncope]. / Prise en charge moderne de la syncope vasovagale.

The management of vasovagal syncope is limited in the majority of cases to reassuring, explaining and advising how to perform some simple methods whose efficacy is assured. When repeated episodes of syncope significantly alter the quality of life, which is the case in about 1% of patients, the management requires medications which are proposed on the basis of as yet uncertain pathophysiological data (beta-blockers, alpha-stimulants, serotonin re-uptake inhibitors), or non-drug treatment (orthostatic training, cardiac pacing). However, none of these treatments has been proved in a randomised study. In these severe and disabling forms, the doctor has to make a choice between empirical prescibing, preferably midodrine, and a more rational strategy guided by an intercritical recording obtained with an implanted ECG monitor which allows better selection of patients who might benefit from pacemaker implantation.

[Role of antiarrhythmic drugs in reducing the number of defibrillation shocks]. / Place des anti-arythmiques dans la réduction du nombre de chocs des défibrillateurs.

There is a logical basis for the prescription of antiarrhythmic therapy (AAT) in patients with an implanted automatic defibrillator (IAD): the prevention of supraventricular and ventricular arrhythmias, slowing the rate of a ventricular arrhythmia to improve the haemodynamic tolerance and better efficacy of anti-tachycardia stimulation. Adjuvant therapy of this kind is used in 49 to 69% of cases. Forty six per cent of patients in the MADIT I trial had AAT at the last follow-up. In the AVID trial, despite recommendations to avoid the association of AAT and [AD, 18% of patients had this combination because of the large number of shocks in 64% of cases; AAT was associated with both a reduction in the number of shocks (p < 0.05) and in the delay to a recurrence of the arrhythmia (p < 0.0001). In the CASCADE trial, carried out in survivors of cardiac arrest, the prescription of amiodarone in patients with IAD significantly reduced the number of defibrillation shocks. Finally, almost 40% of patients with IAD have an "arrhythmia storm", sometimes during follow-up, usually requiring the association of AAT. Despite the frequent association of AAT and IAD, the results of this combination have rarely been studied systematically. Only one randomised trial has been published comparing D,L-sotalol and placebo in patients with IAD. The treatment reduced the probability of a first defibrillation shock, whether appropriate or not. Amiodarone has often been proposed in association with IAD in isolated cases. The OPTIC trial (Optimal Pharmacological Therapy in Implantable Cardioverter), currently under way, has three sub-groups of IAD (betablocker, amiodarone and betablocker, sotalol), with the aim of determining the preventive value of each AAT with respect to the IAD performance. In addition to the results of combined treatment, the interaction with the threshold of defibrillation is an important factor which is not clearly understood at present. Class I AAT increases the threshold of defibrillation whereas Sotalol reduced it. Amiodarone has a variable effect, neutral or deleterious. The OPTIC trial should provide valuable information via the sub-analysis of the effects of drugs on the threshold of defibrillation in each of the three arms of the trial.

[Pacemaker longevity. Replacement of the device]. / Longévité des stimulateurs cardiaques. Remplacement du boîtier de stimulateur.

Life expectancy of patients implanted with cardiac pacemakers has largely increased, so that generator replacement is becoming an important part of the activity in most of the implanting centers. In more than 70% of the cases, the indication for pacemaker replacement is normal battery depletion. Since the new devices are more and more sophisticated and smaller, longevity optimization becomes a real challenge. The main determinant of pacemaker longevity is the output programmed for the pulse generator. It mainly depends on the output voltage and duration settings. The pacing impedance and the percentage of time with pacing are other major determinants of pacemaker longevity. Each manufacturer provides specific policy but the battery voltage and internal impedance are the more accurate and easy-to-obtain battery depletion parameters. The magnet rate is still frequently used but is less valuable since it can drop abruptly at the end of battery life. The complication rate of pacemaker replacement is three-fold higher than the one of first implant. Infections, skin erosions and lead related complications are not uncommon. The replacement should be systematically preceded by the checking of several points including the patient's pacemaker dependency, the necessity to replace or extract one or several leads, the venous system status, the compatibility between the new generator and the leads and the necessity to upgrade the pacing system or to change the pacemaker pocket.

[Efficacy of angioplasty of native coarctations of the aorta of the big infant and of the adult with systematic endoprosthesis implantation]. / Efficacité de l'angioplastie des coarctations natives de l'aorte du grand enfant et de l'adulte avec implantation systématique d'endoprothèse.

The angioplasty of native coarcatations of the aorta remains a controversial treatment due to recurrences and the potential risk of aneurysm or of descending aorta dissection during catheterization. The interest of a systematic implantation of an endoprothesis is poorly documented. We report our experience in a small series of 3 patients aged from 7, 28 to 52 years at the moment of the angioplasty of their native aortic coarctation. In all the three cases it corresponded to a "membranous" type, localized a the level of the isthmus without hypoplasia of the aortic arch. All presented a refractory hypertension. One patient presented an intermittent claudication related to a low perfusion of lower limbs. The angioplasty was performed with BIB balloon, associated at the same time with the implantation of a Palmaz P308 stent in two cases and Genesis PG2910P in the last patient. The efficacy was immediate in all the 3 cases with stopping antihypertensive drugs at the very day of the procedure. The immediate results were complicated by a bilateral hematoma of the scarpa in a context of excessive anticoagulation in one patient requiring blood tranfusion. After a follow-up of one, 12 and 21 months, all the 3 patients are asymptomatic without any significant residual hypertension. The control scan of the infant confirmed the absence of re-coarctation. In conclusion, the angioplasty followed by systematic implantation of an endoprosthesis is a safe and effective technique for treating simple forms of native coarctations of the aortic isthmus. It can be proposed as a first line treatment for big infants and adults affected by localized types.

[Results of the surgery of the truncus arteriosus: present implications]. / Résultats de la chirurgie du tronc artériel commun: implications actuelles.

We report our results of truncus arteriosus surgical reparation in a period of 10 years. From January 1993 to November 2003, 17 patients were operated with a median age and weight of 66 days and 3.5 kg respectively. According to the Van Praagh classification there were 13 cases of type A1, 2 cases of type A2 and 2 cases of A4. The connection between the right ventricle and the pulmonary artery was performed by a homograft (n = 12), a Contegra tube (n = 1) or a Barbero-Marcial intervention (n = 4). In one case, a plasty of the truncus was performed. Patients were classified in two groups: group A for those operated between 1993 and 1997 (n = 8) and group B for those operated after 1997 (n = 9). Five patients died (29%) in the post-operative period, 4 in the group A (50%) and one in group B (11%). The mean duration of intensive care stay was 12.2 (+ 7.4) days. Statistical analysis did not reveal any difference between both groups, especially concerning post-operative treatment or prognosis. In the multivariate analysis, an age below 30 days was a risk factor of post-operative death (OR = 16.5, 95% CI = 1.09 - 250; p = 0.043). After a mean follow-up of 3.9 (+ 3.5) years, 2 patients required a redo intervention for replacement of the pulmonary artery homograft. All 12 suvivors are asymptomatic without any pulmonary hypertension. In conclusion, the results of surgical reparation of the truncus arteriosus seem to improve with experience. According to recent progresses in surgery and intensive care, the intervention can be scheduled beyond the neonatal period without additive risk and with potentially less consecutive redo interventions.

Global myocardial index in patients with multisite pacing.

UNLABELLED: Global myocardial index (GMI) is a sensitive echocardiographic indicator of overall cardiac function. The aim of this study was to compare the GMI changes induced by Bi-V pacing to the variations in clinical, electrocardiographic and echocardiographic parameters currently used for evaluation of ventricular resynchronization in order to test the potential marker of positive clinical response. PATIENTS AND METHODS: This study included 35 consecutive patients (pts), aged 65.7+/-7.5 years, implanted with an endocavitary Bi-V pacemaker for drug refractory severe heart failure. NYHA class was evaluated before implantation and at day 30. QRS duration (QRSd), echocardiographic interventricular delay (IVD), and GMI were determined in the paced and non-paced situation at day 1, 7 and 30 after implantation. RESULTS: NYHA class improved from 3.5+/-0.3 to 2.4+/-0.4 (p<0.01). GMI improved significantly (p<0.0001) after Bi-V in all pts from 1.25 +/- 0.5 to 0.77 +/- 0.34 and remained stable all along the study. GMI decrease (dGMI) in pts with NYHA functional class improvement > 0.5 was 0.52 +/- 0.16while dGMI in pts with NYHA functional class improvement < or = 0.5 was 0.21+/- 0.19. dGMI was statistically correlated with IVD shortening (r=0.67, p<0.0001) but not with QRSd shortening. CONCLUSION: The GMI improves during Bi-V pacing, mostly in responders pts and the improvement remains unchanged after the implant. The GMI decrease induced by Bi-V pacing is correlated with the IVD shortening and NYHA functional class improvement.

[The best of cardiac pacing in 2002]. / L'essentiel de 2002 en stimulation cardiaque.

The year 2002 was marked by the publication of several studies for which the results have above all brought confirmation but also disappointment. One of them has even revealed a new therapeutic approach. In patients affected by sinus dysfunction the MOST study has shown the absence of superiority of DDD stimulation over VVI stimulation in respect of death and cerebral vascular accidents. However, double chamber stimulation reduces the risk of atrial fibrillation, the signs of cardiac insufficiency and slightly improves the quality of life. In the field of multisite stimulation, the MIRACLE study has in patients with moderate to severe cardiac insufficiency confirmed the results of the MUSTIC study with a significant improvement relating to the 6 minute walking test, the NYHA class, the quality of life, and the ejection fraction. The 12 and 24 month follow up of patients included in the MUSTIC study has shown the persistence of the observed short term benefit. Hopes for prevention of atrial fibrillation by atrial stimulation piloted by special algorithms have not been confirmed by the results of the PIPAF study except for patients with predominantly spontaneous AV conduction. The significance of stimulation in disabling vaso-vagal syncope has been questioned by the publication of the results of the VPS 2 study. Cardiac stimulation could in the future constitute a new treatment for sleep apnoea syndrome because it has been reported that atrial overdrive significantly reduces the amount of central or obstructive apnoea.

Comparative effects of permanent biventricular and right-univentricular pacing in heart failure patients with chronic atrial fibrillation.

BACKGROUND: One third of chronic heart failure patients have major intraventricular conduction and uncoordinated ventricular contraction. Non-controlled studies suggest that biventricular pacing may improve haemodynamics and well-being by reducing ventricular asynchrony. The aim of this trial was to assess the clinical efficacy and safety of this new therapy in patients with chronic atrial fibrillation. METHODS: Fifty nine NYHA class III patients with left ventricular systolic dysfunction, chronic atrial fibrillation, slow ventricular rate necessitating permanent ventricular pacing, and a wide QRS complex (paced width >or=200 ms), were implanted with transvenous biventricular-VVIR pacemakers. This single-blind, randomized, controlled, crossover study compared the patients' parameters, as monitored during two 3-month treatment periods of conventional right-univentricular vs biventricular pacing. The primary end-point was the 6-min walked distance, secondary end-points were peak oxygen uptake, quality-of-life, hospitalizations, patients' preferred study period and mortality. RESULTS: Because of a higher than expected drop-out rate (42%), only 37 patients completed both crossover phases. In the intention-to-treat analysis, we did not observe a significant difference. However, in the patients with effective therapy the mean walked distance increased by 9.3% with biventricular pacing (374+/-108 vs 342+/-103 m in univentricular;P =0.05). Peak oxygen uptake increased by 13% (P=0.04). Hospitalizations decreased by 70% and 85% of the patients preferred the biventricular pacing period (P<0.001). CONCLUSION: As compared with conventional VVIR pacing, effective biventricular pacing seems to improve exercise tolerance in NYHA class III heart failure patients with chronic atrial fibrillation and wide paced-QRS complexes. Further randomized controlled studies are required to definitively validate this therapy in such patients.

Holodiastolic reversal flow in the common carotid: another indicator of the severity of aortic regurgitation.

Aortic regurgitation (AR) causes an increased diastolic reverse flow at various levels of aorta and its branching vessels. A prospective study was designed to evaluate the feasibility and accuracy of duplex sonography of the common carotid artery (CCA) in patients with various degrees of AR quantified by cardiac angiography. Twenty-four patients, with pure angiographic AR, of mean age 63.5 + 2.5-year old were included. Holodiastolic reverse flow (HRF) was recorded in all seven patients with severe angiographic AR (five with grade III and two with grade IV) and in none of the seventeen patients (eight with grade I and nine with grade II) with mild angiographic AR (p < 0.001). Furthermore, HRF was recorded both in the CCA and in the aorta, where it represents another criterion of severe AR, of six patients with severe angiographic AR and was absent in the eleven patients with grade I or II AR (p < 0.001). Demonstration of HRF in the CCA may be a very helpful criterion in distinguishing patients with severe AR.

Predictive factors of ventricular fibrillation triggered by pause-dependent torsades de pointes associated with acquired long QT interval: role of QT dispersion and left ventricular function.

INTRODUCTION: Death due to acquired torsades de pointes usually is caused by ventricular fibrillation (VF), but the contributing factors to VF triggered by pause-dependent torsades de pointes are not understood. METHODS AND RESULTS: We evaluated 91 patients who fulfilled four criteria: (1) pause-dependent torsades de pointes; (2) prolonged QT interval and/or corrected QT (QTc) (>0.44 sec); (3) long-short initiation sequence; and (4) conditions known to induce pause-dependent torsades de pointes. There were 38 patients with a documented VF (group I) and 53 without VF (group II). Absolute and relative dispersions of QT and QTc were calculated based on the 12-lead standard ECG. Group I differed from group II with regard to myocardial infarction history (32% vs 13%; P = 0.035), left ventricular ejection fraction (44% +/- 14% vs 65% +/- 9%; P < 0.0001), presence of structural heart disease (100% vs 20.8%; P < 0.0001), QT mean (591 +/- 73 msec vs 514 +/- 78 msec; P < 0.0001), QTc mean (563 +/- 76 msec vs 508 +/- 90 msec; P = 0.002), absolute QT dispersion (166 +/- 56 msec vs 84 +/- 49 msec; P < 0.0001), relative QT dispersion (9.9% +/- 3.5% vs 6.3% +/- 3.2%; P < 0.0001), absolute QTc dispersion (158 +/- 57 msec vs 81 +/- 44 msec; P < 0.0001), and relative QTc dispersion (9.9% +/- 3.6% vs 6.2% +/- 3%; P < 0.0001). Multiple regression analysis showed that ejection fraction (P = 0.0001), presence of structural heart disease (P < 0.0001), and relative QTc dispersion (P = 0.038) were the only independent predictors of VF. CONCLUSION: Left ventricular function, presence of structural heart disease, and QTc relative dispersion should be evaluated carefully in patients with conditions susceptible to inducing torsades de pointes.

[Hospital management of atrial fibrillation. Epidemiologic data and therapeutic strategy. Report of 100 consecutive patients]. / Prise en charge hospitalière de la fibrillation auriculaire. Données épidémiologiques et stratégie thérapeutique. A propos de 100 patients consécutifs.

Despite recent large scale trials, the management of atrial fibrillation remains very variable. The authors report the results of a prospective study of the management of atrial fibrillation in their department. One hundred consecutive patients admitted for atrial fibrillation were included in the study. The epidemiological and clinical data and the results of the therapeutic strategy were recorded prospectively. Three embolic complications occurred before hospital admission. The hospital stay was marked by spontaneous reduction of atrial fibrillation in 14 cases in the 6 hours following admission. The therapeutic strategy was the following: 40 arrhythmias were respected (well tolerated, > 1 year or with a left atrium 60 mm). Oral amiodarone (30 mg/Kg and 15 mg/Kg the next day) was given to 22 patients. Only 9 patients (41%) were converted (average delay of 12 hours). Four patients received intravenous amiodarone, reducing two arrhythmias. Twenty patients were treated by external electrical cardioversion of first intent and 14 after failure of pharmacological reduction. All of these procedures, early (after 48 hours anticoagulation and transoesophageal echocardiography), or late (after 1 month of anticoagulation), restored sinus rhythm without complications, especially embolic. This register showed a relatively low efficacy of oral amiodarone in the reduction of atrial fibrillation and underlines the efficacy and safety of external electrical cardioversion, even when performed early.