Objectives: QT dispersion (QTD) is thought to reflect spatial heterogeneity of ventricular refractoriness. We aimed to investigate and compare the effect of nebivolol and Quinapril on the QTD in patients with hypertension.

Material and Methods: Patients with established or newly diagnosed hypertension were included. The QT interval was measured in all leads from a standard 12-lead ECG and QTD was defined as the difference between the maximum and minimum QT interval. The QTD values were corrected for heart rate using Bazett's formula (QTDC).

Results: Groups (Quinapril, n= 27, Nebivolol, n=27) were similar with respect to demografic, echocardiographic, biochemichal and clinical variables. After four weeks of tretament a significant reduction was observed in systolic (p<0,0001 in both groups) and diastolic (p<0,0001 in both group) blood pressure, QTD (p= 0,014 and p= 0,0003 respectively), and QTDC (p= 0,011 and p= 0,0001 respectively). Nebivolol was more efective than Quinapril in reducing diastolic blood presssure (-13±9 and -8±5 p=0,037), while no differences were noted in treatment dependent changes for any other parameters between two groups. The reduction in QT indexes was significant after controlling for the change in blood pressure and heart rate. However the change in heart rate had a significant effect on the change in QTD (F=5.25, p=0.026) and QTDC (F=12.17, p= 0.001).

Conclusion: Short-term antihipertansive treatment with Quinapril or nebivolol improves ventricular repolarization homogeneity, which in part could be explained by the effect of these drugs on the sympathetic nerveous system activity. ©2007, Firat University, Medical Faculty