QT interval measurement by a computer assisted program: A potentially useful clinical parameter

The duration of electrical systole (QT interval) was measured in 72 subjects (48 women and 24 men) who had normal coronary arteries and left ventricular function at cardiac catheterization (group 1). The same measurements were obtained in 100 patients with a normal ECG (from 40 women and 60 men referred to our institution and found normal on noninvasive clinical basis) and compared to a double independent manual calculation (group 2). The computer assisted program was found in reliable in QT interval measurements. In both study groups women showed longer QTc. No difference in QTc duration was seen in subjects taking β-blockers prior to angiography. As compared to group 1, subjects of group 2 showed similar average QTc values. However, 9 out of 100 subjects of group 2 had abnormal QTc as compared with none of group 1 (p