Dispersión del intervalo QT en pacientes ingresados por insuficiencia cardíaca. Determinantes y valor pronóstico

[Cardiac disorders in young women with anorexia nervosa]

INTRODUCTION AND OBJECTIVES

The objective of this study was to compare heart abnormalities in young women with anorexia nervosa and in a control group of the same age and sex. Patients and method. We report a matched case-control study of 30 adolescents with anorexia nervosa and 30 healthy women of the same age with normal weight. An electrocardiogram and echocardiogram were done. Heart parameters were measured on the electrocardiographic tracings, and QT dispersion was defined as the difference between maximum QT and minimum QT in any of the 12 leads. Diameter, mass and left ventricular mass index were measured.

RESULTS

QT and corrected QT intervals were significantly greater in patients with anorexia nervosa than in the control group. QT dispersion and corrected QT dispersion were significantly greater in anorexia nervosa than in the control group (QTd, 59.3 23.0 vs 38.4 8.0 ms; p = 0.000; QTcd, 56.5 24.2 vs. 40.3 21.8 ms; p = 0.011). Left ventricular mass was significantly lower in young women with anorexia nervosa. We found a significant relationship between body mass index and left ventricular mass index, and between the former and corrected QT dispersion.

CONCLUSIONS

Adolescents with anorexia nervosa show significant cardiac disorders in comparison to healthy women of the same age. This finding may be a useful indicator of the risk of arrhythmia and sudden death in patients with anorexia nervosa.

Qt dispersion has no prognostic information for patients with advanced congestive heart failure and reduced left ventricular systolic function

BACKGROUND

QT dispersion is a potential prognostic marker of tachyarrhythmic events and death, but it is unclear whether this applies to patients with congestive heart failure (CHF).

METHODS AND RESULTS

Of the 1518 patients with advanced CHF and left ventricular dysfunction enrolled in the Danish Investigations of Arrhythmia and Mortality on Dofetilide-CHF (Diamond-CHF) study, a baseline ECG was available in 1319 patients. Of these, QT dispersion could be measured in 703 patients. During a median follow-up of 18 months (minimum 1 year), 285 patients (41%) died. The median QT dispersion was 70 ms (34/155 ms [5%/95% percentiles]), with no difference between survivors and nonsurvivors. Survival analysis revealed no prognostic information derived from QT dispersion regarding all-cause mortality (risk ratio 1.00, 95% CI 1.00 to 1.00; P=0.74), cardiac mortality (risk ratio 1.00, 95% CI 1.00 to 1.01; P=0.55), or cardiac arrhythmic mortality (risk ratio 1.00, 95% CI 0.99 to 1.01; P=0.38).

CONCLUSIONS

QT dispersion has no prognostic value regarding all-cause mortality, cardiac mortality, or cardiac arrhythmic mortality for patients with advanced CHF and reduced left ventricular systolic function.