Initial EKGs in Eating Disorders: Why They’re Important and What to Expect
When someone enters treatment for an eating disorder, whether it’s anorexia nervosa, bulimia nervosa, or another form of disordered eating, a standard part of the medical evaluation often includes an electrocardiogram (EKG or ECG). For many patients and families, this might seem unnecessary or even alarming—especially if there are no obvious cardiac symptoms.
But EKGs play a critical role in assessing the medical stability of individuals with eating disorders. They are not just routine—they’re lifesaving.
In this post, we’ll explore why EKGs matter in eating disorder care, what an EKG can reveal, and what you should expect during this quick but important test.
Why Are EKGs Important in Eating Disorder Treatment?
Eating disorders don’t just affect body weight—they affect every organ system, and the heart is particularly vulnerable. Malnutrition, dehydration, purging behaviors (such as vomiting or laxative use), and electrolyte imbalances can all disrupt the heart’s electrical system.
The EKG is a non-invasive tool that helps detect early warning signs of cardiac instability, including:
Bradycardia (abnormally low heart rate)
Prolonged QT interval, which increases the risk of life-threatening arrhythmias
Electrolyte imbalances affecting cardiac conduction (e.g., low potassium or magnesium)
Heart block or abnormal rhythms that may not cause symptoms until they become dangerous
In severe anorexia nervosa, cardiac complications are the most common cause of death, often due to arrhythmia related to electrolyte shifts or cardiac muscle atrophy (Mehler & Brown, 2015).
Who Needs an EKG—and When?
An EKG should be considered during initial medical evaluation for anyone presenting with an eating disorder, particularly if they have:
A low heart rate (typically under 50 bpm in adolescents or adults)
History of purging or laxative/diuretic use
Rapid weight loss or low body weight
Electrolyte abnormalities (especially low potassium, magnesium, or phosphate)
Chest pain, palpitations, dizziness, or fainting
Use of psychiatric medications that may affect the QT interval (e.g., SSRIs, antipsychotics)
EKGs may also be repeated during treatment to monitor for changes in cardiac function—especially when refeeding begins, or medications are introduced.
What the EKG Can Reveal in Eating Disorders
1. Bradycardia (Slow Heart Rate)
Common in malnutrition, especially in anorexia nervosa
The body conserves energy by slowing the heart
Heart rates below 40 bpm, especially with symptoms, may require hospitalization
2. QTc Prolongation
The QT interval represents the time it takes the heart to recharge between beats
A prolonged QTc can lead to torsades de pointes, a potentially fatal arrhythmia
Normal QTc is usually < 450 ms in males and < 470 ms in females
QTc > 500 ms is considered high risk
QT prolongation can result from:
Low potassium or magnesium
Vomiting or diuretic use
Psychotropic medications
Starvation-related cardiac changes
3. U Waves and Other Abnormalities
U waves may appear with hypokalemia
Other changes may indicate conduction delays or ischemia, though rare
Why QTc Prolongation Matters
QTc prolongation doesn’t always cause symptoms—but it’s a critical red flag. In the presence of malnutrition and electrolyte imbalance, it increases the risk for:
Syncope (fainting)
Seizures
Sudden cardiac death
This is why providers will often:
Repeat EKGs regularly in high-risk patients
Delay or modify psychiatric medications with QTc side effects
Monitor and correct electrolytes aggressively
In one study, up to 40% of hospitalized anorexia patients had QTc prolongation, though it often normalized with refeeding and stabilization (Sachs et al., 2016).
What to Expect During an EKG
An EKG is a simple, painless, 5–10 minute test performed in a clinic, hospital, or office. Here’s what happens:
You’ll be asked to lie flat on your back and expose your chest.
12 small sticky electrodes are placed on your chest, arms, and legs.
The EKG machine records your heart’s electrical signals.
The provider reviews the printout for rhythm, rate, and interval measurements.
There’s no electricity delivered—just monitoring. It’s safe and well-tolerated, even in medically fragile patients.
How Often Are EKGs Repeated in Recovery?
It depends on individual risk. EKGs may be repeated:
Daily or weekly during hospitalization
Before and after starting new medications
After significant weight loss or change in electrolytes
Every few weeks to months in outpatient treatment, depending on symptoms
When Is Hospitalization Needed for EKG Abnormalities?
Immediate medical admission is typically recommended if:
QTc > 500 ms
Heart rate < 40 bpm (or < 50 bpm with symptoms)
Syncope, chest pain, or arrhythmia
Severe electrolyte abnormalities
Cardiac symptoms with bradycardia or hypotension
A cardiac monitor may be used in inpatient settings to track rhythm continuously.
Final Thoughts
An EKG might seem like just another test—but in eating disorder treatment, it’s a vital window into the heart’s health. It allows providers to catch silent but serious complications early, guide safe refeeding, and monitor treatment effects.
Most importantly, it’s a reminder that eating disorders are medical illnesses, not just psychological ones—and that healing the body is as important as healing the mind.
References
Mehler, P. S., & Brown, C. (2015). Anorexia nervosa—medical complications. Journal of Eating Disorders, 3, 11.
Golden, N. H., & Katzman, D. K. (2004). Medical complications of eating disorders in adolescents. Journal of Adolescent Health, 33(6), 418–426.
Sachs, K. V., Harnke, B., Mehler, P. S., & Krantz, M. J. (2016). Cardiovascular complications of anorexia nervosa: A systematic review. International Journal of Eating Disorders, 49(3), 238–248.
American Psychiatric Association. (2023). Practice Guidelines for the Treatment of Patients with Eating Disorders.
