Anorexia nervosa causes a number of abnormal findings around the body, and that includes within the heart. The heart muscle can thin and be starved, which can decrease its function. As well, the body's electrolytes can be abnormal, which can alter the electrical conduction properties of the heart. Several of the changes that can happen in the conduction system include bradycardia (slow heart rate), abnormal abnormal ECG waves, prolongation of the corrected QT interval QTc), and arrhythmias (some of them lethal). A U wave can actually be a normal finding. It is a wave found after the T wave (the waves routinely seen on the ECG include the P wave, the QRS complex, and the T wave). The concern comes if the U wave is at least half (some references say at least 1/3) the size of the preceding T wave. This means that the length of this wave has to be added to that of the QT interval in calculating the QTc. And, a QTc interval >0.46 in girls is a risk for lethal arrhythmias. As an aside, QTc corrections at heart rates below 60 are often inaccurate, as the formula that governs this loses accuracy at very low and very high rates. Without evaluating your daughter or her ECG, I cannot tell whether hers is abnormal, or not.
My recommendation is that she be evaluated by a pediatric cardiologist. As well, she may require hospitalization in a hospital that is used to managing pediatric eating disorders. She may need cardiac monitoring until she has been appropriately refed and has a more normal ECG.
Thank you Doctor for the thorough explanation. My daughter is in an outpatient program at Penn State Hershey right now, I fear that if she doesnt respond well here, she eventually will be sent to the Hospital.
I am now waiting for the result of her second EKG.