QT interval dispersion in admitted to hospital patients with heart failure. Determinants and prognostic value

Introduction and objectives. The determinants and the prognostic value of t he QT interval dispersion are analysed in a group of consecutive patients a dmitted to hospital with heart failure. Methods. One hundred twenty-two consecutive patients admitted because of he art failure in whom a reliable measurement of QT dispersion in the first el ectrocardiogram was obtained (maximum QT - minimum QT) mere studied. The ma in clinical, analytic and echocardiographic data were recorded. A control g roup (n = 35) matched in age and sex with the study group was also analysed . Results. The study group showed a greater QT dispersion than the control gr oup (62 +/- 30 vs 40 +/- 21 ms; p = 0.01). Those cases with a QT dispersion > 80 ms (n = 50; 41%) exhibited a lower natremia (138 +/- 6 vs 141 +/- 4 m Eq/l; p = 0.01), a higher probability of ischemic aetiology (52 vs 33%; RR = 2,2; IC95% 1.05-4.7; p = 0.04), an increased mortality during the first y ear (20 vs 6%; RR = 4.7; IC95% 1.3-16; p = 0.01) and during the whole follo w-up (38 vs 19%; RR = 3.4; IC95% 1.3 a 8.6; p = 0.01) than those patients w ith a QT dispersion < 80 (n = 72; 59%). There were no significant differenc es between both groups with regard to the clinical, analytic or echocardiog raphic data. In the multivariate analysis only the ischemic etiology (p = 0 .002) and the NYHA grade (p = 0.02) were related to a greater mortality. Conclusions. Patients with heart failure show an increased QT interval disp ersion. This parameter is a simple tool that suggests an ischemic etiology and can help in prognosis stratification.