Progress in the management of arrhythmias: risk scores, ablation, and anticoagulation

For the podcast associated with this article, please visit https://academic.oup.com/eurheartj/pages/Podcasts. Arrhythmias are an important cause of symptoms and sudden death. As a rule and with the exception of atrial fibrillation, supraventricular arrhythmias mainly cause symptoms such as palpitations, anxiety, chest tightness, and dizziness,1 while ventricular arrhythmias are potentially lethal.2,3 In addition, atrial fibrillation is an important cause of stroke.4,5 Thus, proper treatment of these conditions is of great importance and, indeed, over the last two decades we have experienced enormous progress in their management. In particular, catheter-based ablation made certain supraventricular arrhythmias such as atrioventricular reentrant tachcardia, among others, curable—a rare outcome in cardiovascular medicine.6 In addition, while most antiarrhythmic drugs proved ineffective or dangerous in patients with ventricular arrhythmias, modern implantable cardioverter defibrillators are important tools in the prevention of sudden cardiac death. Further progress in this field is summarized in ‘The year in Cardiology 2017: arrhythmia and cardiac devices’ authored by Jan Steffel from the University of Zurich in Switzerland and Cecilia Linde from the Karolinska Hospital in Stockholm, Sweden.7 Their overview looks back at the year 2017 and discusses new data from treatment of ablation and anticoagulation of atrial fibrillation and ventricular tachycardias, to risk stratification and prevention of sudden cardiac death. During the last decade, with refinement of the tools, techniques, and experience, catheter-based ablation has increasingly been used for rhythm control in atrial fibrillation.8 and may even improve outcomes, at least in those with successful procedures.9 In their manuscript entitled ‘Temporal trends in atrial fibrillation recurrence rates after ablation between 2005 and 2014: a nationwide Danish cohort study’, Jannik Langtved Pallisgaard and colleagues from the Gentofte Hospital in Hellerup, Denmmark investigated whether the recurrence rate of atrial fibrillation following ablation has improved during the last decade.10 Recurrent atrial fibrillation after ablation was identified in 5425 Danish patients undergoing a first-time ablation between 2005 and 2014, with 1-year follow-up in all the patients. While patient median age increased over time, the median atrial fibrillation duration prior to ablation decreased. The rates of recurrent atrial fibrillation decreased from 45% in 2005–2006 to 31% in 2013–2014, with the relative risk of recurrent atrial fibrillation almost halved with an odds ratio of 0.57 in 2013–2014 compared with 2005–2006. Female gender, hypertension, atrial fibrillation duration >2 years, and cardioversion within 1 year prior to ablation were all associated with an increased risk of recurrence. Thus, the success rate of first-time ablation for atrial fibrillation has markedly increased over the last few years, with hypertension, female sex, previous cardioversion, and prolonged duration of atrial fibrillation as risk factors of recurrence. These encouraging findings are further discussed in an Editorial by Jonathan P. Piccini from the Duke University Medical Center in Durham, North Carolina, USA.11 The association between atrial fibrillation and dementia, most probably due to repetitive cerebral emboli, is well documented.12,13 However, it is uncertain whether oral anticoagulation offers protection. In a further article entitled ‘Less dementia with oral anticoagulation in atrial fibrillation’, Leif Friberg and colleagues from the Karolinska Institute at Danderyd Hospital in Stockholm, Sweden retrospectively compared the incidence of new dementia in 444 106 patients with atrial fibrillation treated with and without oral anticoagulants.14 Those on anticoagulants at baseline had a 29% lower risk of dementia than those without it, and a 48% lower risk if analysed on treatment (Figure 1, left). Interestingly, new oral anticoagulants and warfarin did not differ (Figure 1, right). These exciting real-world results and their consequences for clinical practice are further discussed in an Editorial by Renato Lopes from Duke Medical Center in Durham, North Carolina, USA. 15 Anticoagulation in atrial fibrillation and dementia. Unadjusted incidence of dementia in relation to oral anticoagulant treatment among 161 896 patients with atrial fibrillation and no previous diagnosis of dementia who were propensity score matched for the likelihood of oral anticoagulant treatment at baseline (from Friberg L, Rosenqvist M. Less dementia with oral anticoagulation in atrial fibrillation. See pages 453--460). Based on a large body of evidence,16–18 current ESC Atrial Fibrillation Guidelines19 discourage antiplatelet monotherapy as an alternative to anticoagulants. Why antiplatelet monotherapy continues to be used is unknown.20 In their manuscript entitled ‘Characteristics of patients with atrial fibrillation prescribed antiplatelet monotherapy compared with those on anticoagulants: insights from the GARFIELD-AF registry’, Freek W.A. Verheugt and colleagues from the Onze Lieve Vrouwe Gasthuis in Amsterdam, The Netherlands studied this issue further in 51 270 patients of the GARFIELD-AF registry, with most of them having CHA2DS2-VASC score ≥2.21 Overall, 21% received antiplatelet monotherapy, 52% anticoagulants only, 14% both, and the remainder none. Compared with patients on anticoagulants only, patients on antiplatelet monotherapy were frequently Chinese and more likely to have persistent atrial fibrillation, a history of coronary artery disease or other vascular disease, and a history of bleeding or dementia. The odds for antiplatelet monotherapy increased with 5-year age increments for patients 75 years of age or older, but decreased with age increments for younger patients (Figure 2). Antiplatelet monotherapy patients were less likely to have paroxysmal or permanent atrial fibrillation, a history of embolism, or alcohol use. Of note, about half of antiplatelet-treated patients had no indication for it except atrial fibrillation, although 71% had a CHA2DS2-VASC score ≥2. Thus, prescription of antiplatelet monotherapy in newly diagnosed atrial fibrillation has declined, but even nowadays a substantial proportion of antiplatelet-treated patients with atrial fibrillation have no indication for such drugs. These concerning real-world results are put into context in an Editorial by Jeff S. Healey from McMaster University in Hamilton, Ontario, Canada.22 Antiplatelet therapy in atrial fibrillation in the GARFIEL-AF registry: adjusted odds ratios and 95% confidence intervals for the prescription of antiplatelet monotherapy vs. anticoagulant monotherapy. The reference group for the binary variables is no history of the condition (for vascular disease, bleeding, ACS, dementia, systemic embolism, stroke/TIA), and light/moderate/heavy vs. abstinent alcohol use. Odds ratios were adjusted for all variables in the model (from Verheugt FWA, Gao H, Al Mahmeed W, Ambrosio G, Angchaisuksiri P, Atar D, Bassand J-P, John Camm A, Cools F, Eikelboom J, Kayani G, Lim TW, Misselwitz F, Pieper KS, van Eickels M, Kakkar AK; for the GARFIELD-AF Investigators. Characteristics of patients with atrial fibrillation prescribed antiplatelet monotherapy compared with those on anticoagulants: insights from the GARFIELD-AF registry. See pages 464--473). In atrial fibrillation, mortality remains high despite effective anticoagulation.23 A model predicting the risk of death in these patients is currently not available. Thus, in their paper entitled ‘A biomarker-based risk score to predict death in patients with atrial fibrillation: the ABC (age, biomarkers, clinical history) death risk score’, Ziad Hijazi and colleagues from the Uppsala Clinical Research Center in Sweden report on the development and internal validation of their risk score in 14 611 patients.24 The most important predictors of death were NT-proBNP, troponin-T, growth differentiation factor-15 (GDF-15), age, and heart failure, and these were included in the ABC (age, biomarkers, clinical history) death risk score. The score was well calibrated and yielded higher c-indices than a model based on all clinical variables in both the derivation and validation cohorts. The reduction in mortality with apixaban was most pronounced in patients with a high ABC death score. The clinical value and usefulness of this novel score is put into clinical context in an thought-provoking Editorial by William Stevenson from the Vanderbilt University Medical Center in Nashville, Tennessee, USA).25 The editors hope that this issue of the European Heart Journal will be of interest to its readers.