By Caroline Rudnick MD, PhD
Cardiovascular complications of eating disorders are common and can be very serious. They may present with chest pain. It is important to determine if this symptom is coming from the heart or from another cause such as gastroesophageal reflux, muscular strain or anxiety. As patients with anorexia lose weight, they lose muscle mass, both of the skeletal and cardiac type. When patients lose cardiac muscle mass, they can develop mitral valve prolapse. This can give the symptom of sharp pain beneath the sternum. It is a benign condition which can improve with weight gain. Chest pain could also be from a much more ominous cause – heart failure. A very weakened heart could result in congestive heart failure. Heart failure could also be the result of very low serum phosphorus in the refeeding syndrome. If properly treated, heart failure does have the potential to improve. Other symptoms associated with heart failure are shortness of breath, fatigue, tachycardia or a relative tachycardia, and edema.
Anorexia nervosa does have a high risk of death – about half of the deaths are sudden cardiac deaths. These are the result of cardiac arrhythmias. Why patients with eating disorders are prone to sudden cardiac death is not known for certain. Prolonged QT intervals on electrocardiogram (ECG) predispose patients to a type of arrhythmia called torsade de pointes, which then can degenerate to a deadly arrhythmia known as ventricular fibrillation. Prolonged QT can be a result of quick weight loss or severe weight loss. It can also be a result of electrolyte disturbances (specifically low potassium and low magnesium) and certain medications. In the case of a patient with anorexia, it may be a combination of these factors. QT dispersion has also been noted in patients with anorexia nervosa and seems to put patients with this finding at higher risk of sudden cardiac death. This is a variation in the QT interval between the leads of the ECG. It is not known why this happens in patients with anorexia, but may have to do with myofibrillar degeneration, a finding that has been seen in anorexic patients on heart MRI. This refers to degeneration of the cardiac muscle fibers.
Cardiomyopathy, or literally sick heart, can be caused in eating disorders by starvation or by the chronic use of emetics such as ipecac. Fortunately, ipecac has been taken off the market so this cause is seen much less in the United States. Chronic alcohol abuse, which can be comorbid with eating disorders, is also a cause of cardiomyopathy. Certain nutritional deficiencies are also rarely known to cause cardiomyopathy (magnesium and thiamine are examples). Severe cardiomyopathy can lead to heart failure or be a risk factor for a heart arrhythmia.
Bradycardia or heart rate less than 60 beats per minute and hypotension or blood pressure less than 90/50 are very common in anorexia nervosa, in patients who are less than 80% of ideal body weight. The bradycardia is due to an overactive parasympathetic nervous system, in the body’s attempt to conserve energy. The hypotension is due to the weakened heart muscle. Dehydration can also be a contributor to hypotension. If the patient’s bradycardia is severe, i.e. less than 40 bpm and accompanied by hypotension, the patient should be hospitalized for monitoring. If the patient with bradycardia develops a rhythm other than sinus rhythm on the ECG, this is also a reason for hospitalization for monitoring. These problems can be alleviated by good nutrition and weight gain.
In normal weight patients with eating disorders, such as those with bulimia nervosa, the biggest cardiac risk is that of having an arrhythmia due to an electrolyte abnormality, such as low serum potassium or low serum magnesium.
In overweight or obese patients with eating disorders, the cardiac risk of having low potassium if the patient purges is still present. Moreover, in obese patients with eating disorders, such as binge eating disorder, the risks of hypercholesterolemia, hypertension and diabetes are high. All of these can lead to cardiac complications such as atherosclerotic heart disease and congestive heart failure.
Cardiovascular complications in eating disorders are very common. Unfortunately, the presence of untreated eating disorders and severe eating disorders greatly increases the patient’s risk of morbidity and mortality from these cardiovascular complications. Fortunately, most of them are reversible or at least treatable with proper medical eating disorder treatment of good nutritional rehabilitation and attention to the vascular status and electrolyte status of the individual.
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About the author:
Caroline Rudnick MD, PhD graduated from Washington University in 1995 with an MD and a PhD in molecular biology. She completed an internship and residency in Family Medicine at St. John’s Mercy Medical Center in St. Louis. The final year of residency, she served as the chief resident. She worked in primary care medicine for 14 years. For the past 10 years, she has been on the faculty of St. Louis University. For the past 6 years, she has concentrated her clinical efforts on the care of eating disorder patients at McCallum Place St. Louis and the outpatient facility that is associated with it, Webster Wellness Professionals.