There are multiple types of congenital long QT syndrome, but 3 comprise about 80% of cases.
Main types:
(1) LQT1
(2) LQT2
(3) LQT3
Shared features:
(1) prolongation of the QT interval
(2) reduction in net repolarizing current in cardiac myocytes
|
Type
|
Gene
|
Manifestations
|
|
LQT1
|
KCNQ1
|
sudden cardiac death during exercise, especially swimming, or higher sympathetic tone
|
|
LQT2
|
KCNH2
|
triggered by loud or sudden noises, hypokalemia or immediate postpartum period
|
|
LQT3
|
SCN5A
|
sudden cardiac arrest while sleeping or during rest
|
There are at least 18 other types affecting genes (see Giudicessi et al).
