Clinical inquiry & computer simulation of RR-QT system suggest functional long QT episodes in borderline subjects

We report direct experimental estimations of time constant in RR-QT system (/spl tau//sub QT/) using pharmacological or electrophysiological manipulations of heart rate (HR). We find by means of using computer simulation that /spl tau//sub QT/ size may be introduced in borderline subjects (QTc>450 ms for males) under current life stress episodes of functional long QT with "risk surface" comparable with that of patently long QT patients.