Long QT syndrome Type 2 (LQT2) is caused by loss-of-function mutations in KCNH2 (hERG), reducing IKr. Which specific trigger most commonly provokes arrhythmia in LQT2 compared with LQT1?
- A Auditory stimuli (sudden loud noises, alarm clocks) and emotional arousal during rest/sleep ✓
- B Vigorous exercise and swimming (high adrenergic state)
- C Sleep and rest (bradycardia-dependent QT prolongation)
- D Cold water exposure
Correct answer: A. Auditory stimuli (sudden loud noises, alarm clocks) and emotional arousal during rest/sleep
Explanation
LQT1 (IKs deficiency) arrhythmias are typically triggered by exercise and swimming. LQT2 (IKr/hERG deficiency) is classically precipitated by sudden auditory stimuli (telephone ringing, alarm clocks, doorbell) and emotional stress, particularly at rest or during sleep. LQT3 (INa gain-of-function) events occur at rest/sleep (bradycardia-dependent). This distinction guides lifestyle advice and is tested in NEET PG. LQT2 patients should avoid sleeping near loud alarms and should mute phones at night.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.