What electrocardiogram (ECG) changes occur in anorexia nervosa?

From the Guidelines

Anorexia nervosa commonly causes several ECG changes due to malnutrition, electrolyte abnormalities, and structural cardiac changes, with the most frequent findings being sinus bradycardia and QT interval prolongation, as noted in the 2023 American Psychiatric Association practice guideline for the treatment of patients with eating disorders 1. The most frequent ECG finding is sinus bradycardia, with heart rates often below 60 beats per minute, resulting from increased vagal tone as an energy-conserving adaptation. QT interval prolongation is another significant change, which increases the risk of dangerous arrhythmias like Torsades de Pointes. Low QRS voltage may appear due to cardiac muscle atrophy and decreased electrical activity. ST segment and T wave abnormalities are common, reflecting electrolyte disturbances, particularly hypokalemia and hypomagnesemia. Patients may also develop conduction abnormalities such as first-degree AV block or bundle branch blocks. These ECG changes correlate with the severity of malnutrition and can improve with nutritional rehabilitation, though some may persist despite weight restoration. Regular ECG monitoring is essential in anorexia patients, especially during refeeding when electrolyte shifts can worsen cardiac abnormalities, as recommended by the American Psychiatric Association 1. Key considerations in managing anorexia nervosa include individualized goals for weekly weight gain and target weight, eating disorder-focused psychotherapy, and family-based treatment for adolescents and emerging adults with involved caregivers, as outlined in the 2023 guideline 1. It is crucial to prioritize the patient's medical, psychiatric, psychological, and nutritional needs through a coordinated multidisciplinary team approach, as emphasized in the guideline 1. By following these recommendations and closely monitoring ECG changes, healthcare providers can help reduce the risk of morbidity and mortality associated with anorexia nervosa, particularly from cardiac complications, as highlighted in the 2006 acc/aha/esc guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death 1.

From the Research

ECG Changes in Anorexia Nervosa

• The most common ECG findings reported in the literature are sinus bradycardia and changes in depolarization, as shown by prolongation and increased dispersion of the QT interval 2.
• Electrolyte disturbances seem to be the cause of these disturbances in some patients, but other reasons are also discussed in detail, such as QRS right axis deviation, disturbances of heart rate variability, low R wave voltage in V6, amplitude decrease of the QRS and T wave, and QRS prolongation 2.
• Marked repolarization changes (QT interval and/or T wave morphology) in AN should not be taken as a feature of the disease, but should call for the search of potential causes such as metabolic and electrolytic disturbances, drug effects, or a possible genetic component 3.
• The QTc interval was not significantly correlated with left ventricular mass, left ventricular mass index, BMI or resting energy expenditure in patients with anorexia nervosa 4.
• A number of cardiac abnormalities associated with anorexia nervosa have been described in the literature, including pericardial and valvular pathology, changes in left ventricular mass and function, conduction abnormalities, bradycardia, hypotension, and dysregulation in peripheral vascular contractility 5.

Reversibility of ECG Changes

• The majority of authors report that ECG changes are reversible after treatment of anorexia nervosa 2.
• Weight restoration and attention to these cardiac changes are crucial for a successful treatment outcome 6.

Clinical Recommendations

• It is reasonable to obtain routine electrocardiography and measurements of orthostatic vital signs in patients presenting with anorexia nervosa 5.
• Echocardiography is generally not indicated unless prompted by clinical signs of disease 5.
• Admission to an inpatient unit with telemetry monitoring is recommended for patients with severe sinus bradycardia or junction rhythm, marked prolongation of the corrected QT interval, or syncope 5.