Additional references are mentioned with ‘w’ in the main text and can be found on the online addenda along with 5 figures (1, 6, 7, 9, 11, 12) and 10 tables (3, 4, 5, 9, 11, 12, 19, 21, 22, 23). They are available on the ESC website only at http://www.escardio.org/guidelines-surveys/esc-guidelines/Pages/cardiac-pacing-and-cardiac-resynchronisation-therapy.aspx

Additional references are mentioned with ‘w’ in the main text and can be found on the online addenda along with 5 figures (1, 6, 7, 9, 11, 12) and 10 tables (3, 4, 5, 9, 11, 12, 19, 21, 22, 23). They are available on the ESC website only at http://www.escardio.org/guidelines-surveys/esc-guidelines/Pages/cardiac-pacing-and-cardiac-resynchronisation-therapy.aspx

Hypertrophic cardiomyopathy is a genetic disease associated with a risk of ventricular tachyarrhythmias and sudden death, especially in young patients.

The risk of sudden death in patients with hypertrophic cardiomyopathy (HCM) has been known for almost 50 years.^1-6 Indeed, this disease is the most common cause of sudden cardiac death in young people,^1-6 including trained athletes.⁷ However, only in the last few years has the implantable cardioverter-defibrillator (ICD) been systematically used as a potentially life-saving treatment in high-risk patients with HCM.^8-10 Since HCM represents a less common indication for ICDs than coronary artery disease^11-14 it is important to document its effectiveness in a large HCM population. In addition, although there is little residual controversy regarding the appropriateness of ICDs for secondary prevention, considerable uncertainty persists concerning patient selection for prophylactic ICD therapy in HCM. Therefore, to provide insights into these important clinical issues, we report here the findings in a large, international, multicenter cohort of patients with HCM who have received an ICD.

Atrial fibrillation (AF) confers a substantial risk of mortality and morbidity from stroke and thrombo-embolism, and this common cardiac arrhythmia represents a major healthcare burden in Europe.¹ Stroke prevention is central to the management of AF patients, with the 2012 focused update of the European Society of Cardiology (ESC) guidelines² recommending oral anticoagulation (OAC) using well-controlled adjusted dose vitamin K antagonists (VKAs, e.g. warfarin) or non-VKA oral anticoagulants (NOACs, previously referred to as new or novel OACs³) for patients with AF and ≥1 stroke risk factor(s). Also, these guidelines strongly advocate a clinical practice shift so that the initial decision step now is the identification of ‘truly low risk’ patients, essentially those aged <65 years without any stroke risk factor (both male and female), who do not need any antithrombotic therapy.² The ESC guidelines also recommend the use of the CHA₂DS₂-VASc score⁴ for stroke risk assessment, and define ‘low-risk’ patients as those with a CHA₂DS₂-VASc score = 0 (males) or score = 1 (females). Subsequent to this initial step of identifying the low-risk patients, effective stroke prevention (which is essentially OAC) can then be offered to AF patients with ≥1 stroke risk factor(s), with treatment decisions made in consultation with patients and incorporating their preferences.

The aim of this study was to assess the association between maximum daily atrial fibrillation (AF) burden and risk of ischaemic stroke. Cardiac implanted electronic devices (CIEDs) enhance detection of AF, providing a comprehensive measure of AF burden. A pooled analysis of individual patient data from five prospective studies was performed. Patients without permanent AF, previously implanted with CIEDs, were included if they had at least 3 months of follow-up. A total of 10 016 patients (median age 70 years) met these criteria. The risk of ischaemic stroke associated with pre-specified cut-off points of AF burden (5 min, 1, 6, 12, and 23 h, respectively) was assessed. During a median follow-up of 24 months, 43% of 10 016 patients experienced at least 1 day with at least 5 min of AF burden and for them the median time to the maximum AF burden was 6 months (inter-quartile range: 1.3–14). A Cox regression analysis adjusted for the CHADS₂ score and anticoagulants at baseline demonstrated that AF burden was an independent predictor of ischaemic stroke. Among the thresholds of AF burden that we evaluated, 1 h was associated with the highest hazard ratio (HR) for ischaemic stroke, i.e. 2.11 (95% CI: 1.22–3.64, P = 0.008). Device-detected AF burden is associated with an increased risk of ischaemic stroke in a relatively unselected population of CIEDs patients. This finding may add to the basis for timely and clinically appropriate decision-making on anticoagulation treatment.