Primary prevention with the ICD in clinical practice: not as straightforward as the guidelines suggest?

Guidelines for implantable cardioverter defibrillator (ICD) implantation are a necessary reference for clinical decision-making in primary prevention of sudden cardiac death in patients with left ventricular systolic dysfunction. They may seem straightforward at first sight with clear cut-off values for inclusion primarily based on the ejection fraction.1-3 However, risk is not dichotomous as suggested, nor equally distributed: some patient groups may profit more while in others ICD therapy may even be futile. Furthermore, patients may differ from the trial populations from which the predictive models have been derived and remain exposed to the risk of sudden death beyond the duration of the trials in real life. Recently, there has been a reappraisal of benefits and potential hazards of ICD therapy.4 The purpose of this paper is to reflect on the guidelines considering known and potential risk factors that may help in risk stratification in clinical practice. …