Dynamic assessment of the electrocardiographic QT interval during citrate infusion in healthy volunteers.

12 healthy teetotallers aged 19-36 years who were not receiving medication known to influence calcium homoeostasis.

Variable rate trisodium citrate infusion designed to 'clamp' the whole blood ionised calcium concentration 0.20 mmol/l below baseline for 120 min.

Whole blood ionised calcium concentration and QaTc intervals (onset of the Q wave to T wave apex divided by the square root of the RR interval).surrogate