BACKGROUND: @entity1162 ( @entity1162 ) is an @entity74 that causes @entity1163 and @entity944 . Although its genetic basis has become well-understood, the mechanisms whereby mutations translate to @entity943 susceptibility in the in situ @entity1 heart have not been fully defined. We used noninvasive ECG imaging to map the cardiac electrophysiological substrate and examine whether @entity1162 @entity1 display regional heterogeneities in repolarization, a substrate that promotes arrhythmogenesis. METHODS AND RESULTS: Twenty-five subjects (9 @entity9677 , 9 @entity9678 ) with genotype and phenotype positive @entity1162 underwent ECG imaging. Seven normal subjects provided control. Epicardial maps of activation, recovery times, activation-recovery intervals, and repolarization dispersion were constructed. Activation was normal in all @entity1 . However, recovery times and activation-recovery intervals were prolonged relative to control, indicating delayed repolarization and abnormally long action potential duration (312  30 ms versus 235  21 ms in control). Activation-recovery interval prolongation was spatially heterogeneous, with repolarization gradients much steeper than control (119  19 ms/cm versus 2.0  2.0 ms/cm). There was variability in steepness and distribution of repolarization gradients between and within @entity1162 types. Repolarization gradients were steeper in symptomatic @entity1 (130  27 ms/cm in 12 symptomatic @entity1 versus 98  19 ms/cm in 13 asymptomatic @entity1 ; P<0.05). CONCLUSIONS: @entity1162 @entity1 display regions with steep repolarization dispersion caused by localized action potential duration prolongation. This defines a substrate for reentrant @entity943 , not detectable by surface ECG. Steeper dispersion in symptomatic @entity1 suggests a possible role for ECG imaging in risk stratification.

Electrophysiologic substrate in XXXX : noninvasive mapping with electrocardiographic imaging (ECGI).

@entity1 :: ('9606', 'Species') :: ['human', 'patients'] @entity9677 :: ('3784', 'Gene') :: ['LQT1'] @entity944 :: ('MESH:D003645', 'Disease') :: ['sudden death'] @entity9678 :: ('3757', 'Gene') :: ['LQT2, 5 LQT3, and 2 LQT5'] @entity1163 :: ('MESH:D013575', 'Disease') :: ['syncope'] @entity74 :: ('MESH:D030342', 'Disease') :: ['arrhythmogenic disorder'] @entity1162 :: ('MESH:D008133', 'Disease') :: ['LQTS', 'Congenital Long QT syndrome'] @entity943 :: ('MESH:D001145', 'Disease') :: ['arrhythmias', 'arrhythmia']
@entity1162 :: (MESH:D008133,Disease) :: ['congenital Long QT syndrome']
