Symptomatic bradycardia in the emergency department may have several causes (excessive vagal tone, drug toxicity, acute myocardial ischemia, sick sinus syndrome, heart block, and electrolyte imbalance); among these, hyperkalemia may develop as a complication of chronic medical treatment with angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers, and must be considered in the early approach to the bradyarrhythmic patient with possible electrocardiographic signs of hyperkalemia. We report a case of an 87-year-old woman with a clinical history of chronic angiotensin-receptor blocker consumption that led her to dangerous bradyarrhythmia, cardiogenic syncope, and risk of sudden cardiac death.