Over the last two decades, the number of patients receiving implantable cardiac defibrillators (ICDs) for the prevention of sudden cardiac death has grown significantly. This growth is largely the result of broadened indication for ICD use because of the success of trials demonstrating efficacy. Early ICD indication centered on secondary prevention, which then advanced to primary prevention in high-risk patients. Nurses delivering care to these patients not only manage this complex technology but also patients’ uncertainty about their survival and related psychosocial adjustment to receiving an ICD. To inform practice, theoretical models such as Mishel’s (1988) uncertainty in illness model provide insight into such acute phases of illness. This article proposes expansion of the uncertainty in illness model to advance knowledge in this field for nurses caring for patients with ICD.