Cardiac Manifestations of Anorexia Nervosa and Their Management
Anorexia nervosa causes significant cardiac abnormalities including structural changes, conduction abnormalities, and hemodynamic alterations that contribute to its high mortality rate, with most manifestations being reversible with appropriate nutritional rehabilitation. 1
Cardiac Manifestations
Structural Changes
- Cardiac muscle atrophy and reduced left ventricular mass due to malnutrition 1, 2
- Pericardial effusions occurring in approximately 25% of patients 2
- Reduced cardiac output compared to healthy controls 2
- Decreased left ventricular and left atrial dimensions 3
Electrical/Conduction Abnormalities
- Sinus bradycardia (heart rate <50 bpm in approximately half of cases) 4
- Prolongation of QTc interval, a risk factor for sudden cardiac death 1, 4
- Increased QT dispersion 1
- Ventricular arrhythmias, particularly during refeeding 1
Hemodynamic Changes
- Hypotension and orthostatic changes 1, 5
- Blunted heart rate response to exercise 3
- Altered diastolic function with increased E/A ratio 2
Assessment and Monitoring
Initial Evaluation
- Assessment of vital signs including temperature, resting heart rate, blood pressure, orthostatic pulse, and orthostatic blood pressure 1
- Comprehensive physical examination looking for signs of malnutrition 1
- Electrocardiogram to evaluate for QTc prolongation and other conduction abnormalities 1
Laboratory Testing
- Complete blood count to assess for anemia 1
- Comprehensive metabolic panel including electrolytes, liver enzymes, and renal function tests to detect electrolyte abnormalities 1
- Special attention to phosphate levels, particularly during refeeding 1
Advanced Testing
- Echocardiography when clinically indicated to assess for structural changes, pericardial effusions, and ventricular function 6, 2
- Consider telemetry monitoring for patients with severe bradycardia, junction rhythm, marked QTc prolongation, or syncope 6
Management Approach
Nutritional Rehabilitation
- Carefully controlled refeeding to reduce the risk of ventricular arrhythmias and sudden cardiac death 1
- Individualized goals for weekly weight gain and target weight 1
- Avoid prolonged, unbalanced, very low-calorie diets as they may provoke life-threatening arrhythmias 1
Monitoring During Refeeding
- Close cardiac monitoring during the first week of refeeding when risk of "refeeding syndrome" is highest 1
- Particular vigilance in severely malnourished patients (less than 70% ideal body weight) 1
- Regular monitoring of electrolytes, especially phosphate, during refeeding 1, 5
Treatment of Specific Cardiac Complications
- Ventricular arrhythmias should be treated according to standard protocols for arrhythmia management 1
- For patients with postural tachycardia syndrome (POTS), consider increased salt and fluid intake to expand plasma volume 5
- In cases of symptomatic inappropriate sinus tachycardia, beta-blockers or ivabradine may be considered after nutritional rehabilitation 5
Prognosis and Recovery
- Most cardiac manifestations of anorexia nervosa are reversible with appropriate nutritional rehabilitation 1, 4
- Cardiac dimensions typically increase toward normal with weight restoration 3
- Left ventricular mass may increase by approximately 20% following nutritional rehabilitation 3
- Heart rate and blood pressure typically normalize with weight restoration 3
Important Considerations and Pitfalls
- Up to one-third of deaths in anorexia nervosa are attributed to cardiac causes 1, 4
- Low weight, low BMI, and rapid weight loss immediately preceding assessment are important predictors of QTc interval prolongation 1
- Cardiac complications of refeeding syndrome typically occur within the first week and are associated with severe malnutrition 1
- Admission to an inpatient unit with telemetry monitoring is recommended for patients with severe bradycardia, junction rhythm, marked QTc prolongation, or syncope 6