Arrhythmias: drugs and devices.

Arrhythmias of supraventricular and ventricular origin are an important health issue due to mortality, morbidity, and the impaired quality of life of patients with which it is associated, but are also economically relevant due to the physician’s visits, hospitalizations, and interventions they lead to. For certain arrhythmias such as bradycardia of different origin and ventricular tachycardia and fibrillation, the utilization of cardiac implants such as pacemakers and implantable cardioverter defibrillators (ICDs) has enriched our therapeutic armamentarium. As a result, these treatment options are recommended by current guidelines in defined patient populations. The ever-increasing technological complexity of these devices is matched by the shear omnipresence of electric, magnetic, and electromagnetic fields, both in every day life and at work. As electromagnetic interference potentially bears a risk for such patients, physicians increasingly have to advise patients exposed to intermittent electromagnetic interference or chronic occupational exposure. In a timely Review article entitled ‘Are patients with cardiac implants protected against electromagnetic interference in daily life and occupational environment?’ Nikolaus Marx from the University Hospital Aachen in Germany provides clinically useful insights into the function and susceptibility of implantable electronic devices to non-medical electromagnetic fields. Atrial fibrillation is the most common arrhythmia and its prevalence increases in ageing societies. Although the arrhythmia may cause symptoms in certain patients, the real threat for patients is the risk of stroke, – 7 particularly in those with persistent as opposed to paroxysmal atrial fibrillation. Rivaroxaban is a direct oral anticoagulant increasingly used to prevent stroke in atrial fibrillation. A special patient population are those treated with catheter-based ablation procedures rather than antiarrhythmic drugs. In a FAST TRACK clinical research manuscript entitled ‘Uninterrupted rivaroxaban vs. uninterrupted vitamin K antagonists for catheter ablation in non-valvular atrial fibrillation’ Andrea Natale and colleagues from the Texas Cardiac Arrhythmia Institute in Austin, USA report the results of VENTURE-AF, the first prospective randomized trial comparing uninterrupted rivaroxaban 20 mg daily with dose-adjusted uninterrupted vitamin K antagonists in 248 patients with non-valvular atrial fibrillation and a CHA2DS2-VASc score of 1.6 prior to catheter ablation. The primary endpoint was major bleeding, while secondary endpoints included thrombo-embolic events (stroke, systemic embolism, myocardial infarction, and vascular death), other bleeding events, and other procedure-attributable events. During the study period, the incidence of major bleeding was low (i.e. 0.8%; one major bleeding event), as were thrombo-embolic events (i.e. 1.6%). All events occurred in the dose-adjusted uninterrupted vitamin K arm and all after catheter ablation. The numbers of any adjudicated events, any bleeding events, and any other procedureattributable events were similar with rivaroxaban and vitamin K antagonists. The authors therefore conclude that in patients undergoing catheter ablation for atrial fibrillation, uninterrupted oral rivaroxaban appears to be a safe alternative to uninterrupted VKA therapy. Since its introduction by Haissaguerre in 1998, catheter-based pulmonary vein isolation has often been the preferred treatment strategy for atrial fibrillation. In the second clinical research paper ‘A minimal or maximal ablation strategy to achieve pulmonary vein isolation for paroxysmal atrial fibrillation: a prospective multicentre randomized controlled trial (the Minimax study)’ Alex McLellan and colleagues from the Alfred Hospital and Baker Heart and Diabetes Institute in Melbourne performed a randomized multicentre study to compare the outcomes of circumferential antral pulmonary vein isolation alone (i.e. minimal ablation) vs. circumferential antral pulmonary vein isolation with intervenous ridge ablation to achieve individual pulmonary vein isolation (i.e. maximal ablation) in 234 patients with paroxysmal atrial fibrillation. The primary outcome of recurrent atrial arrhythmia was assessed with 7-day Holter monitoring at 6 and 12 months. Pulmonary vein isolation was achieved in all patients, with ablation time being longer in the maximal group (i.e. 47 vs. 42 min). After 17 months, freedom from atrial fibrillation after a single procedure did not differ between groups and was 70% in the minimal and 62% in the maximal ablation strategy. The authors conclude that freedom from atrial fibrillation did not differ with a minimal or maximal ablation strategy. Despite attempts to achieve pulmonary vein isolation with antral ablation, intervenous ridge ablation is commonly required. Patients in whom antral isolation can be achieved without intervenous ridge ablation have higher longterm freedom from atrial fibrillation. The results are discussed in a thought-provoking Editorial by Lluı́s Mont from the University of Barcelona in Spain. The risk of stroke in patients with atrial fibrillation depends importantly on patient characteristics such as age and gender, as well as the presence of hypertension, diabetes, and heart failure. The CHA2DS2-VASc score is a clinical risk stratification tool, which estimates the risk of stroke and thrombo-embolism in non-valvular atrial fibrillation based on such parameters. In the third clinical research paper ‘Prognostic value of CHA2DS2-VASc score in