The PMHNP working on an inpatient eating disorders unit is evaluating a 17-year-old girl with suspected anorexia nervosa. Her laboratory results reveal elevated serum cholesterol levels, elevated serum salivary amylase concentrations, and decreased fasting glucose concentrations. Which electrocardiography (ECG) changes will help confirm the diagnosis?

Choice A reason: While mild ECG changes may occur in some patients, anorexia nervosa often produces identifiable cardiac changes, making “no significant ECG changes” less accurate. Choice B reason: Ventricular tachycardia is less common in anorexia nervosa unless there is severe electrolyte imbalance or secondary cardiac pathology. Choice C reason: Sinus bradycardia is frequently observed in patients with anorexia nervosa due to malnutrition, decreased metabolic demands, and increased vagal tone, making it a classic ECG finding supportive of the diagnosis. Choice D reason: Torsades de pointes is a life-threatening arrhythmia associated with severe electrolyte disturbances, more typical in acute refeeding syndrome rather than as a baseline diagnostic finding in anorexia nervosa.