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Background: The risk of sudden cardiac death (SCD) is high early after myocardial infarction (MI). Current knowledge and guidelines mainly rely on results from older clinical trials and registry studies. Left ventricular ejection fraction (LVEF) alone has not been proven a reliable predictor of SCD., Objectives: This study sought to identify the incidence and additional predictors of SCD early after MI in a contemporary nationwide setting., Methods: The authors used data from SWEDEHEART, the Swedish Cardiopulmonary Resuscitation Registry, and the Swedish Pacemaker and Implantable Cardioverter-Defibrillator (ICD) Registry. Cases of MI, which had undergone coronary angiography and were discharged alive between 2009 to 2017 without a prior ICD, were followed up to 90 days. Cox regression models were used to assess associations between clinical parameters and out-of-hospital cardiac arrest (OHCA)., Results: Among 121,379 cases, OHCA occurred in 349 (0.29%) and non-OHCA death in 2,194 (1.8%). A total of 6 variables (male sex, diabetes, estimated glomerular filtration rate <30 ml/min/1.73 m 2 , Killip class ≥II, new-onset atrial fibrillation/flutter, and impaired LVEF [reference ≥50%] categorized as 40% to 49%, 30% to 39%, and <30%) were identified as independent predictors, were assigned points, and were grouped into 3 categories, where the incidence of OHCA ranged from 0.12% to 2.0% and non-OHCA death from 0.76% to 11.7%. Stratified by LVEF <40% alone, the incidence of OHCA was 0.20% and 0.76% and for non-OHCA death 1.1% and 4.9%., Conclusions: In this nationwide study, the incidence of OHCA within 90 days after MI was <0.3%. A total of 5 clinical parameters in addition to LVEF predicted OHCA and non-OHCA death better than LVEF alone., Competing Interests: Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background Risk stratification of sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM) is mainly based on evaluations from patients at highly specialized centers. Aim To evaluate risk markers for appropriate implantable cardioverter defibrillator (ICD) therapy in an unselected, nationwide cohort of HCM. Methods Patients with an ICD due to HCM were identified from the Swedish ICD Registry since its start in 1995, merged with Patient Register data, and medical records were retrieved. Risk markers for ventricular arrhythmias leading to appropriate ICD therapy were analyzed using Cox proportional hazard ratio (HR). Results Of 321 patients (70.1% males), at least one appropriate therapy occurred in 77 (24.0%) during a mean follow-up of 5.4 years (5.3% per year; primary prevention 4.5%, secondary prevention 7.0%). Cumulative incidences at 1 year, 3 years, and 5 years were 8.1%, 15.3%, and 21.3%, respectively. Cardioversion effectively restored rhythm in 52% of the first episode and antitachycardia pacing was sufficient in the remaining. For the whole cohort, ejection fraction (EF) <50% (HR 2.63; P < 0.001) was associated with appropriate ICD therapy. In primary prevention, patients with established risk markers experienced appropriate therapy; atrial fibrillation (AF; HR 2.54; P = 0.010), EF < 50% (HR 2.78; P = 0.004), and nonsustained ventricular tachycardia (HR 1.80; P = 0.109) had the highest HR, and wall thickness ≥30 mm, syncope, exercise blood pressure response, or family history of SCD had weaker associations. Conclusion ICD therapy successfully terminates ventricular arrhythmias in HCM. In addition to conventional risk markers, a history of AF or EF < 50% may be considered in risk stratification. [ABSTRACT FROM AUTHOR]