Population (clinical features) | Interventions | |||
Avoid triggers including medications that prolong the QT interval (www.crediblemeds.org) when possible* | Beta blockade with a nonselective beta blocker (nadolol or propranolol) | Implantable cardioverter/ defibrillator (ICD) | Left cardiac sympathetic denervation (LCSD) | |
History of sudden cardiac arrest (SCA) | All individuals | All individuals | Usually appropriate. However, if SCA occurred in a patient with LQT1 before the diagnosis was made and there is a strong desire to avoid an ICD, a non-ICD treatment with beta blockade and LCSD is possible. | Can be used to intensify treatment if VF-terminating ICD shocks occur. |
History of symptoms (arrhythmogenic syncope and arrhythmogenic syncope followed by seizures) | All individuals | All individuals | Generally indicated for symptomatic LQT2 (for women with QTc >500 ms, men with QTc >500 ms) and symptomatic LQT3 with QTc >550ms. | Can be used if beta blockade is not tolerated or if there is a breakthrough event despite adherence to beta blockade. |
Asymptomatic with prolonged QT interval on ECG | All individuals | All individuals | Can be considered for asymptomatic individuals with LQT2 or LQT3 who has a QTc >500 ms. | Can be considered if beta blockade is not tolerated. |
Normal ECG (QTc <470 ms) with positive genetic testing for a congenital LQTS-susceptibility variant | All individuals | Individualized decision; often suggested for family members identified by variant-specific cascade testing | Not indicated. | Not indicated. |
LQTS: long QT syndrome; ICD: implantable cardioverter/defibrillator; LCSD: left cardiac sympathetic denervation; SCA: sudden cardiac arrest; VF: ventricular fibrillation; ms: milliseconds; ECG: electrocardiogram.
* Besides medications that prolong the QT interval, other triggers for QT prolongation and/or LQTS-triggered cardiac events may include dehydration, hypokalemia, hypomagnesemia, some types of exercise (such as swimming in LQT1), and in some patients, loud noises and psychologic stress. Refer to UpToDate for a complete list.Do you want to add Medilib to your home screen?