SCN5A and Ventricular arrhythmia: There are three main subtypes depending on the specific mutation that account for over 90% of LQTS: LQTS1 (responsible gene KCNQ1), where ventricular arrhythmia is triggered by exercise; LQTS2 (KCNH2), where emotional stress triggers the condition; and LQTS3 (SCN5A), where sleep serves as the trigger.