A 23-year-old woman has had 2 episodes of syncope during the past month. Her mother witnessed 1 episode in which the patient collapsed and lost consciousness for a few minutes. She experienced tonic-clonic seizure activity but no subsequent confusion. Her mother is also concerned about her daughter's amenorrhea and obsessive preoccupation with weight and appearance. The mother reports purging behavior, which the patient denies. On further questioning, the patient states with pride that she has lost 20 lb during the previous 6 months. A review of systems reveals cold intolerance and fatigue. The patient is 70 in tall and weighs 102 lb (body mass index [BMI], 15). Her blood pressure is 90/53 mm Hg; heart rate is 43 beats per minute. The patient is thin but in no apparent distress. She has fine lanugo- type hair over her face and arms. Results of neurologic, pulmonary, and abdominal examinations are normal. However, cardiovascular examination reveals a soft systolic murmur and mid systolic click consistent with mitral valve prolapse. A baseline chemistry panel demonstrates mild hypokalemia (potassium level, 3.1 mEq/L); all other components are normal. A complete blood cell count and thyroid and liver function tests are also normal. A 12-lead ECG demonstrates sinus bradycardia with prolongation of the QT interval (Figure 1). Immediate 24-hour Holter monitoring is ordered. The patient returns to her physician's office 2 days later and reports 1 episode of profound dizziness but no syncope. A review of Holter monitor data shows that this event correlated with a short, self-terminating episode of polymorphic ventricular tachycardia, consistent with torsade de pointes (Figure 2). The patient is admitted to the hospital for cardiac monitoring and further management. MAKING THE DIAGNOSIS Patients with anorexia nervosa are frequently in denial. Often, a family member urges the patient to seek medical attention because of concern about substantial weight loss. In contrast to medically ill patients, those with anorexia are unconcerned about their weight loss. A high index of suspicion for this disorder is warranted, because patients often present with nonspecific symptoms or amenorrhea. Many severely anorectic patients have fine lanugo-type hair on the sides of their face and arms, brittle nails, and thinning hair. They may also report cold sensitivity, abdominal pain, light-headedness, and fatigue. The Diagnostic and Statistical Manual of Mental Disorders lists the following criteria for anorexia nervosa1:

• Intense fear of weight gain.
• Undue preoccupation with body shape.
• Body weight less than 85% of predicted.
• Amenorrhea for 3 consecutive months.

Our patient met all of these criteria. In addition to eating disorders, the differential diagnosis in this case could include primary cardiac arrhythmia (eg, congenital long QT syndrome), use of QT-prolonging drugs, malabsorption syndrome, and hypermetabolic syndrome. Only rarely do serious symptoms, such as syncope, occur. Syncope that results from an anorexiarelated cardiac arrhythmia may be confused with a seizure disorder. CARDIAC COMPLICATIONS OF ANOREXIA Some of the deaths among patients with anorexia may result from cardiac complications (Table 1). One of the most common cardiovascular features of this disease is sinus brady-cardia. This may in part be an adaptive response to weight loss and negative energy balance. However, abnormally elevated cardiac vagal activity has been demonstrated in patients with anorexia.² This suggests that bradycardia in this setting may not be entirely physiologic, nor should it be dismissed as a normal adaptation to athletic conditioning, despite the fact that many affected patients exercise compulsively. Another common cardiac abnormality is mitral valve prolapse, which often remits with weight gain.³ Clinically important mitral valve regurgitation is, however, exceedingly infrequent. A rare but potentially lethal complication is congestive heart failure that results from the rapid refeeding of cachectic patients.⁴ The exact mechanism underlying this phenomenon is unclear, although evidence suggests a potentially important role for hypophosphatemia.⁵ Anorexia is also associated with pericardial effusion,⁶ which should be suspected when a chest film reveals an enlarged cardiac silhouette. Anorexia can result in hypercholesterolemia. However, autopsy studies do not demonstrate significant coronary artery disease.⁷ This suggests that despite a high incidence of sudden death in patients with anorexia, premature coronary artery disease is probably not the cause. The most likely explanation for premature sudden death in patients with anorexia is ventricular arrhythmia, in particular torsade de pointes. This form of polymorphic ventricular tachycardia occurs exclusively in the setting of QT-interval prolongation and is often triggered during periods of bradycardia. A study of 58 patients with anorexia nervosa demonstrated QT prolongation in nearly half.8 The authors also found a 2-fold increase in QT dispersion (a strong marker of arrhythmia risk) in these patients compared with controls. Clinical factors that correlated with QT prolongation were low BMI, rapid rate of weight loss, and a low serum sodium level. INDICATIONS FOR IMMEDIATE HOSPITALIZATION Although there are no evidencebased criteria for hospitalization, indications center on cardiac instability (Table 2). If the heart rate of a patient with moderate or severe anorexia is below 40 beats per minute, inpatient cardiac monitoring may be indicated. Hospitalization may be warranted if atrioventricular block is detected, although advanced conduction abnormalities are exceedingly rare in anorexia.² Hospitalization may also be indicated for patients with symptomatic hypotension, syncope, rhythms other than sinus, or a markedly prolonged QT interval (more than 500 milliseconds). When the QT interval is only modestly prolonged (470 to 500 milliseconds), hospitalization may be indicated if concomitant profound electrolyte imbalance is detected.