The Seattle Proportional Risk Model (SPRM) is a calculator of estimated proportion of sudden death in patients with heart failure with reduced ejection fraction (primarily EF≤35%) to illustrate the variable the benefit of a primary prevention ICD. SPRM is designed for use by health care providers knowledgeable in cardiac medicine. Patients should only use SPRM when their healthcare providers are present, such as at a doctor's office. Please click the option below that applies to you: I am a healthcare provider. I am not a healthcare provider.