9.5. Vital signs and ECG
There was no clinically relevant change of heart rate or blood pressure
during the course of the study for the two groups. ECG measurements
included QTc interval, QRS duration, and PR interval. The QTc
interval was calculated using Bazett's formula (QTcB = QT ∕ RR1/2).
At the last visit, the mean changes of QTc intervals were −11.0 ms
(SD = 33.4) for aripiprazole and −3.5 ms (SD = 38.1) for risperidone
(Fig. 4). Clinical significance was operationally defined as a QTc of 450
ms or more and a 10% or greater increase from baseline. No subjects experienced
a potentially clinically significant increase in QTc intervals.
Furthermore, no trends were observed for any potentially clinically
significant changes in QRS duration and PR interval.