Q. Is there any new information about young patients with anorexia nervosa (AN) and suspicious cardiovascular signs? That is, is there a way to predict cardiac complications besides the amount of weight loss and chronic nature of the illness? I’ve read that even an echocardiogram can’t detect subtle changes in myocardial function. (H.Y., Omaha, NE)
A. Cardiovascular complications are common among patients with AN, and have been reported in up to 80% of cases. This is problematic when young AN patients don’t have conventional clinical symptoms such as bradycardia and hypotension. Clinicians still don’t have longitudinal markers of myocardial adaptation to eating disorders.
In a retrospective pilot study at Goryeb Children’s Hospital, Morristown, NJ, pediatrician Philip T. Levy and his colleagues used conventional echocardiography and a newer imaging technique, myocardial strain analysis, to evaluate ventricular function in children newly diagnosed with AN and a group of age-, gender- and race-matched controls (Global Pediatric Health. 2017; 4:4). Global and regional strain imaging uses two-dimensional speckle tracking echocardiography-driven strain imaging of the left ventricle. The higher the magnitude of strain, the better the LV function.
One of the clues that emerged from the authors’ study was the presence of ventricular remodeling found in the subgroup of young patients with purging behaviors Most of the AN patients, who had a median age of 13 years, reported risky behaviors: 23 (77%) exercised excessively, 5 (17%) had purging behaviors, and all had restrictive eating behaviors.
There were no differences in electrolyte levels between the AN patients with purging behavior and those without purging behavior. While the mechanism is still not clear, purging behavior may alter torsional mechanisms and decrease electric excitation of cardiac motion that begins at the apex and has a slower transit time to the base, according to an earlier study by two of the authors (Echocardiography. 2016; 29:209).
According to the National Institutes of Health, purging behaviors may increase the risk of hypokalemia and subsequent cardiac dysrhythmias (Vasc Health Risk Manag. 2012; 8: 91). Thus, monitoring vital signs and performing electrocardiograms and serial measurements of plasma potassium are relevant. The presence of purging behaviors increases cardiovascular risk. Medical problems associated with laxative abuse include electrolyte and acid/base changes that can involve the renal and cardiovascular systems and may become life-threatening. The same applies to the use/abuse of emetics.
Dr. Levy and fellow researchers feel that echocardiography-derived strain imaging holds promise for assessing LV function in young patients newly diagnosed with AN, who are at increased risk for developing serious cardiac dysfunction.