LQT syndrome (congenital)

Last edited 08/2022 and last reviewed 11/2022

The hereditary long QT syndrome is characterised by prolonged ventricular repolarisation. There is a significant risk of syncope, torsade de pointes and sudden death.

Hereditary long QT syndrome has a prevalence of about 1:5000 (1).

Predominant inheritance - Majority AD. Rarer forms AR

Variations in genes encoding for cardiac ion channels, accessory ion channel subunits or proteins modulating the function of the ion channel have been identified as disease-causing mutations in up to 75% of all long QT syndrome cases (4)

Presentation - Often asymptomatic.Syncope, arrhythmias or sudden cardiac death (SCD)

  • annual rate of SCD in asymptomatic patients with untreated LQTS has been estimated to be less than 0.5%, while it increases to around 5% in those with history of syncope (5)
  • mean age at presentation is 14 years (5)

Reference:

  1. British Heart Foundation (March 2006). Arrhythmias and Sudden Death - Implications for GPs.
  2. Shwartz, K. (1994). On the pulse of genetic cardiology. Nature Genet. 8, 110-1.
  3. British Heart Foundation (2009).Factfile 5/09, Inherited cardiovascular disease.
  4. Wilde AAM, Amin AS, Postema PG.Diagnosis, management and therapeutic strategies for congenital long QT syndrome. Heart Published Online First: 26 May 2021. doi: 10.1136/heartjnl-2020-318259
  5. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: Developed by the task force for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death of the European Society of Cardiology (ESC) Endorsed by the Association for European Paediatric and Congenital Cardiology (AEPC), European Heart Journal, 2022;, ehac262, https://doi.org/10.1093/eurheartj/ehac262