Re-entrant arrhythmias in simulations of the long-QT syndrome

In the congenital LQTS, repolarisation of the ventricles is prolonged and patients with LQTS are at an increased risk of ventricular arrhythmias. Four LQTS phenotypes have been identified LQT1, LQT2 and LQT4 affect potassium channels, and LQT3 affects sodium channels. The incidence of arrhythmias is higher in LOT1 but the incidence of lethal arrhythmias is higher in LQT3. The aim of the study was to compare re-entry in simulations of LQT1 and LQT3 myocardium. We modified the Oxsoft equations for the guinea pig ventricular cell to simulate 30 mm/spl times/30 mm 2 dimensional LQT1 and LQT3 preparations Although there was no difference in vulnerable period between normal, LQT1 and LQT3 simulations re-entrant wave meander was 3.6 times greater in LQT1 than normal, but only 1.3 times greater in LQT3 than normal. We propose that the greater meander in LQT1 explains the higher incidence of self terminating non-lethal arrhythmias in this phenotype.