RH Clayton, A Bailey, VN Biktashev, AV Holden
University of Leeds, UK
Abstract
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 LQT1, but the incidence of lethal arrhythmias is higher in LQT3.
The aim of this 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 x 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.