Reduction of the QT interval dispersion after aortic valve replacement reflects changes in electrical function rather than structural remodeling.

BACKGROUND AND AIM OF THE STUDY: Factors related to changes of QT dispersion (QTd) after aortic valve replacement (AVR) in patients with aortic stenosis were analyzed. METHODS: The prospective group comprised 121 consecutive patients (45 women, 76 men; mean age 58 +/- 11 years; range: 24-77 years) with significant aortic valve stenosis. Data (clinical, echocardiographic and electrocardiographic) were collected before and at least 16 months after AVR. QTd was measured in the standard ECG. RESULTS: Before AVR, the mean QTd was 60 +/- 24 ms (QT(max) 424 +/- 40 ms). QTd was > 50 ms in 68% of patients, and > 70 ms in 30%. During postoperative follow up the mean QTd was 54 +/- 19 ms (QT(max) 368 +/- 36 ms) for all patients, and was > 50 ms in 58% of cases and > 70 ms in 13%. Postoperatively, QTd was decreased to < 70 ms in 27% of patients with a normalized left ventricular mass index (LVMI), and in 27% of those without any clinically significant reduction in left ventricular (LV) hypertrophy. In the multivariate analysis, QTd reduction was weakly related to the reduction in LV wall thickness (p = 0.09) and LVMI (p = 0.05). The reduction in QTd was more related to changes in T-wave amplitude in lead V5 (p = 0.004). CONCLUSION: Following AVR for aortic stenosis, a decrease in QTd was observed, notably among patients with QTd > 70 ms. This reduction was only weakly related to the degree of reduction in cardiac hypertrophy, but a more important relationship was observed with changes in T-wave amplitude. These findings suggest that a reduction in QTd after AVR is reflective of changes in electrical function rather than structural remodeling.