Sudden Death Risk-Stratification in 2018–2019: The Old and the New

Sudden Cardiac Death (SCD) is a major public health issue, accounting for half of all cardiovascular deaths world-wide. The implantable cardioverter-defibrillator (ICD) has been solidified as the cornerstone therapy in primary prevention of SCD in ischaemic and non-ischaemic cardiomyopathy. However, what has become increasingly clear is that the left ventricular ejection fraction (LVEF) is an inadequate tool to select patients for a prophylactic ICD, despite its widespread use for this purpose. Use of LVEF alone has poor specificity for arrhythmic versus non-arrhythmic death. In addition, the vast majority of sudden deaths occur in patients with more preserved cardiac function. Alternate predictors of sudden death include electrophysiology study, non-invasive markers of electrical instability, myocardial fibrosis, genetic and bio-markers. The challenge for the future is finding a risk stratification test, or combination of tests, that adequately select patients at high risk of SCD with low competing risk of non-sudden death.