Cybersecurity hazards pose a myriad of threats to the emergency department function. In this chapter we focus specifically on emergency departments in the U.S. acknowledging there is variation in this function worldwide. With high technological integration, historically poor cyber defense, and potentially catastrophic consequences of disruption - healthcare systems are particularly vulnerable to cyberattack. While discussions of cyberattacks on healthcare systems often focuses on privacy breaches involving the disclosure of personally identifiable information (PII) and protected health information (PHI) which can be resolved with civil litigation, instead we focus exclusively on the disruptive impacts of cyberattacks on hospital emergency departments which extend more importantly to patient continuity-of-care and patient mortality. This chapter is an updated summary with feedback from a paper originally presented at the ACM CCS Cybersecurity in Healthcare (HealthSec) Workshop held in Salt Lake City Utah USA October 2024 [47]. We outline the broad range of potential impacts that cyberattacks have on the delivery of emergency medicine. We discuss downstream consequences of clinical care challenges, infrastructure vulnerabilities, and system-wide ramifications of impaired hospital IT infrastructure as well as potential solutions. We leverage the available literature from a clinical and emergency management lens to highlight the potential consequences of cyberattacks and offer alternative approaches to mitigate and respond to cyberattack disruptions.