Intentional nontherapy in long QT syndrome

Heart Rhythm. 2020 Jul;17(7):1147-1150. doi: 10.1016/j.hrthm.2020.02.017. Epub 2020 Feb 24.


Background: International guidelines advise universal beta-blocker therapy as either a class I (symptomatic or QTc ≥470 ms) or class II (asymptomatic and QTc <470 ms) recommendation for treatment of long QT syndrome (LQTS).

Objective: The purpose of this study was to evaluate the outcomes of a highly selected cohort of patients with LQTS managed with an observation-only (intentional nontreatment) strategy.

Methods: The cohort was derived from a comprehensive retrospective registry of patients with LQTS. Clinical phenotype and genotype data were collected via review of electronic health records.

Results: Among 661 patients with LQTS, 55 (8.3%) asymptomatic patients (53% female; 16 age <18 years) were managed with intentional nontherapy. Only preventative measures were advised. Mean age at diagnosis was 37.8 ± 21.2 years. Mean QTc was 448 ± 30 ms. None of the patients experienced an LQTS-triggered cardiac event over mean follow-up of 7.5 ± 4.3 years. Compared to the larger treated cohort, this intentionally untreated cohort was less symptomatic, was older at diagnosis, and had lower resting QTc values (P <.0001).

Conclusion: After careful clinical evaluation, risk assessment, and institution of precautionary measures, an observation-only strategy may be considered in a highly selected group of LQTS patients with a clinical profile that includes asymptomatic status, older age at diagnosis, and QTc <470 ms, with excellent outcomes and better quality of life than LQTS patients treated with beta-blocker. LQTS patients with this low-risk profile should not receive a prophylactic implantable cardioverter-defibrillator.

Keywords: Genetics; Ion channels; Long QT syndrome; Sudden cardiac arrest; Sudden cardiac death.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-Antagonists / therapeutic use*
  • Adult
  • Death, Sudden, Cardiac / prevention & control*
  • Defibrillators, Implantable*
  • Electrocardiography
  • Female
  • Follow-Up Studies
  • Humans
  • Long QT Syndrome / complications
  • Long QT Syndrome / therapy*
  • Male
  • Quality of Life*
  • Registries*
  • Retrospective Studies
  • Risk Assessment / methods*
  • Risk Factors
  • Young Adult


  • Adrenergic beta-Antagonists