Samuel Lévy

Atrial fibrillation is a common arrhythmia which consequences include disabling symptoms, haemodynamic impairment and frightening embolic complications. In 3/4 cases, they are represented by cerebrovascular accidents responsible of death or disabling sequella. Underlying heart disease is present in 70% of AF patients. Endpoints of therapy include: 1. prevention of embolic complications using oral anticoagulation in patients at risk; 2. control of symptoms and prevention of haemodynamic impairment either by restoring and maintaining sinus rhythm or by controlling ventricular heart rate. The same principles should be applied for emergency treatment: aside from AF with haemodynamic compromise (hypotension or syncope) which requires urgent electrical cardioversion, AF termination may be obtained with intravenous or oral antiarrhythmic therapy or the treatment confined to slowing of heart rate. Selecting the appropriate antiarrhythmic therapy for prevention of recurrences is based on the...

Although paroxysmal atrial fibrillation (AF) is known to be initiated by rapid firing of pulmonary veins (PV) and non-PV triggers, the crucial role of cardiac autonomic nervous system (ANS) in the initiation and maintenance of AF has long been appreciated in both experimental and clinical studies. The cardiac intrinsic ANS is composed of ganglionated plexi (GPs), located close to the left atrium-pulmonary vein junctions and a vast network of interconnecting neurons. Ablation strategies aiming for complete PV isolation (PVI) remain the cornerstone of AF ablation procedures. However, several observational studies and few randomized studies have suggested that GP ablation, as an adjunctive strategy, might achieve better clinical outcomes in patients undergoing radiofrequency-based PVI for both paroxysmal and nonparoxysmal AF. In these patients, vagal reactions (VR) such as vagally mediated bradycardia or asystole are thought to reflect intrinsic cardiac ANS modulation and/or denervatio...

Pulmonary vein isolation (PVI) using cryoballoon (CB) technique and cavotricuspid isthmus (CTI) ablation using radiofrequency (RF) are established interventions for drug-resistant atrial fibrillation (AF) and typical atrial flutter (AFL). Twelve patients with a mean age of 62±12years underwent simultaneous delivery of RF energy at the CTI during CB applications at the PV ostia. Pulmonary vein isolation was achieved in all PVs and sustained bidirectional CTI conduction block obtained in all patients. The reported ablation protocol of combined paroxysmal AF and typical AFL did not result in prolongation of the procedure duration or in prolonged radiation exposure when compared to CB-PVI alone. No interferences between both ablation energy systems were observed. These preliminary results suggest that combined paroxysmal AF and typical AFL can be successfully and safely ablated using hybrid energy sources with simultaneous CTI ablation using RF during CB applications at the PV ostia.

The prognostic value of heart rate (HR) was analysed based on the reports from the literature in the general population and in patients with coronary artery disease (CAD). Multivariate analyses showed that elevated resting HR was found to be an independent predictor of total and cardiovascular mortality. The behaviour of HR during exercise testing was predictive of sudden death. The beneficial effects of betablockers in post-infarction patients are well established. Calcium channel blockers that increase resting HR are associated with a deleterious effect on mortality. Therefore, resting HR should not be overlooked in risk stratification of CAD patients. Reduction of resting HR should be viewed as an attractive therapeutic target in CAD patients.

There has been increasing interest in the last decade in the role played by the autonomic nervous system in tachycardia induction and termination [1–3]. Furthermore, recent reports have provided evidence that accessory pathway properties may be influenced by exercise and catecholamines [4–8]. Most of the data available concern atrioventricular (AV) pathways, and we shall focus our discussion on this type of accessory connection which is associated with the Wolff-Parkinson-White (WPW) syndrome. As developed elsewhere in this volume, tachyarrhythmias associated with WPW syndrome include both reciprocating tachycardias and atrial flutter-fibrillation. The changes induced by exercise and catecholamines on both normal pathway and accessory pathway may affect both types of tachyarrhythmias.

Ivabradine is a novel pure heart rate-lowering agent that selectively and specifically inhibits pacemaker I(f) current. Ivabradine has been shown to have antianginal and anti-ischaemic properties in patients with stable angina pectoris. Because f channels are also present in the retina, visual symptoms represent a potential adverse effect of ivabradine that may affect driving performance. The aim of the study was to investigate whether visual symptoms reported after repeated administration of ivabradine at high doses could affect driving performance. This randomized, double-blind, placebo-controlled study was conducted in healthy volunteers. Seventy-five subjects were randomized to ivabradine 10 mg twice daily and 15 subjects to placebo for 7 days, followed by ivabradine 15 mg twice daily or placebo, respectively, for a second week if no visual symptoms were reported. As soon as a subject reported visual symptoms between day 1 and day 14, he or she was assigned to perform driving simulator sessions. If no visual symptoms were reported, driving simulator sessions were performed after 14 days' treatment. Driving parameters included absolute speed, deviation from the speed limit, deviation from the ideal route and number of collisions in different light conditions. In the daylight and evening driving sessions, there was no significant difference in all measured parameters (as indicated by absolute speed, deviation from the speed limit and deviation from the ideal route results) between the ivabradine and the placebo groups, independently of visual symptoms. No collisions were observed in the entire study irrespective of the testing conditions and the treatment groups assessed. No relevant differences were seen in the ivabradine subsets of subjects reporting visual symptoms or not. This study suggests that ivabradine administered at dosages higher than those recommended in the clinic did not affect driving performance regardless of whether or not visual symptoms were present.

Atrial flutter (AFL) and atrial fibrillation (AF) are "fellow-travellers". AF may be a stable, "isolated" rhythm, a bridge between sinus rhythm and AF, or both arrhythmias can coexist. Whether the characteristics of isolated AFL are different from those of patients with AFL combined with AF is still unclear. To compare the clinical characteristics of patients with isolated AFL to those of patients with AFL combined with AF, in a series of patients referred for AFL ablation. Seventy-six consecutive patients (mean age 66.9±12.2 years; 53 men) with a history of electrocardiogram-documented paroxysmal or persistent AFL, referred for catheter ablation, underwent clinical work-up including bidimensional echocardiogram. Patients were subdivided into group I (44 with isolated AFL) and group II (32 with AFL and a history of AF). Underlying heart disease was present in 62 patients (81.6%). Hypertension was the most common cardiac disorder (n=44, 57.9%) and was more prevalent in group II than in group I (75.0% vs 45.5%; P=0.01). Prevalence of prior cardiac surgery was higher in group I (22.7% vs 6.3%; P=0.04). AFL was persistent in 35 group I patients and 17 group II patients (79.5% vs 53.1%; P=0.01). Class I or III antiarrhythmic drug use was more frequent in group II (84.4% vs 45.5%; P=0.001). This study showed significant differences between patients with isolated AFL and those with AFL combined with AF, in the prevalence of underlying heart disease and the use of antiarrhythmic medication, which were higher when both atrial arrhythmias were combined. In turn, the history of cardiac surgery (including atriotomy), was more common in patients with isolated AFL than in those with AFL combined with AF.