Bradycardia and Restrictive Eating Disorders

Eating disorders impact nearly every organ system in the body, and cardiac complications are commonly seen.  The most common cardiac complication seen is bradycardia and it is often the reason that patients are admitted to the hospital with malnutrition. Despite it being common, there still remains quite a bit of confusion when it comes to bradycardia and eating disorders. I hope this helps.

Take Home Points: 

•  Bradycardia can occur in any body size in which weight loss has occurred.  The rate of weight loss is a significant predictor of medical instability, regardless of the current weight.  

• Age matters when assessing heart rate.  Heart rates in children are different than in adults.  Newborns and young children have higher resting heart rates, and it decreases as children get older.  Once an adolescent has gone through puberty, they have a resting heart rate that is similar to an adult (60-100 when awake).  Therefore a pre-pubetal child with anorexia with a heart rate at 60, while considered normal for an older adolescent, would be considered bradycardic for their developmental age and stage and should be taken seriously.  

• Bradycardia may require hospitalization.  Heart rates can get low enough, where medical hospitalization is required.  Keeping in mind that heart rates drop even lower during sleep, the rates can be so low that close cardiac monitoring is required.  The Society of Adolescent Health and Medicine (SAHM), American Academy of Pediatrics (AAP) and American Psychiatric Association (APA) have published guidelines supporting hospitalization at certain heart rate criteria.   If someone’s resting heart rate (while awake) is less than 50 beats per minute, medical hospitalization should be considered. 

• You can feel fine and have a critically low heart rate.  While some people may experience symptoms with a low heart rate such as fatigue, lightheadedness, fainting, shortness of breath, or chest pain, most of the time people feel fine.  This can be deceiving, as it can give patients and families the message that they are less sick than they are.  This is where objective data can be your friend and useful to rely on the numbers.

•  Bradycardia in the context of malnutrition is rarely due to athleticism. I am often asked whether a patient’s low heart rate is a result of being an athlete. While an echocardiogram can reveal structural and functional changes in individuals with eating disorders, it is rarely useful in determining the cause of bradycardia in the setting of malnutrition. To differentiate between athletic bradycardia and bradycardia due to malnutrition, I take the following approach:

  • Assess for other signs of malnutrition. Some examples of red flags include falling off a growth curve, eliminating food groups, loss of menses, lightheadedness or dizziness, cold intolerance, and constipation. If these are present, I am more concerned that bradycardia is a consequence of malnutrition rather than athleticism.

  • Review medical history. Primary care records often provide heart rate data from prior visits, before any weight loss occurred. These baseline measurements help determine whether the current bradycardia is a new finding.

  • Monitor over time. If the heart rate improves with adequate nutrition and weight restoration, this strongly suggests that malnutrition—not athletic conditioning—was the underlying cause.