QT variability among weight-restored patients with anorexia nervosa

Anorexia nervosa (AN) may be complicated by cardiac arrhythmias and sudden death. A single study reported an increased QT variability index (QTVI), a marker for cardiac arrhythmogenicity, in AN patients. The aim of the current study was to further evaluate repolarization dynamics in a large cohort of patients with AN without electrolyte abnormalities and to evaluate previously unreported repolarization dynamics parameters.

Forty-three AN patients and 45 age- and sex-matched controls were included in the study. Twenty-nine AN patients were hospitalized for a mean time of 1.5±1.1 months. The rest were ambulatory AN patients. Electrocardiograms were conducted under strict standards. QT variability index, normalized QT variability (QTVN) and power spectral analysis of QT dynamics were conducted with designated computer software.

None of the patients had an electrolyte imbalance. Although mean QT was higher in AN patients compared with controls, QTc results were similar following corrections for RR interval. There was no significant difference in QTVI, QTVN and power spectral analysis parameters among groups. The results of QTVI and QTVN were comparable to those previously published for healthy individuals. During 3 years of follow-up, no patient developed arrhythmias or suddenly died.

Medically treated AN patients who gained weight and had normal serum electrolytes appeared to have normal QTc and QT variability indexes, reflecting a nonincreased risk for cardiac arrhythmias. We suggest that weight normalization, medical treatment and lack of electrolyte abnormalities are responsible in part for these results. Further evaluation of the prognostic significance of QTVI and QTVN in AN is warranted.