Fig. 10.
Simulation of the cardiac action potential at various stimulation frequencies under control and long QT syndrome type 1 conditions with heterozygous expression of A341V. Using the ten Tusscher model, ventricular action potentials under control (wild-type IKs; A) and long QT syndrome type 1 (A341V; B) conditions were stimulated at 1, 2, and 3 Hz in the absence and presence of isoflurane. For the wild-type conditions, the integrity of the action potential profile was maintained at the various stimulation frequencies; no evidence of arrhythmogenicity was evident in the absence or presence of isoflurane. For the long QT syndrome type 1 conditions, no evidence of arrhythmogenicity was evident at stimulation frequencies of 1 and 2 Hz. However, at 3 Hz, early afterdepolarizations were apparent in the absence and presence of isoflurane. IKs = slowly activating delayed rectifier potassium channels.