Intentional Non-Therapy in Long QT Syndrome (LQTS)

Ciorsti J MacIntyre 1, Ram K Rohatgi 2, Alan M Sugrue 3, J Martijn Bos 4, Michael J Ackerman 5

Affiliations

PMID: 32105774
DOI: 10.1016/j.hrthm.2020.02.017

Abstract

Background: International guidelines advise universal beta blocker therapy as either a class I (symptomatic or QTc > 470 ms) or class II recommendation (asymptomatic and QTc < 470 ms) in the treatment of Long QT Syndrome (LQTS).

Objective: This study sought to evaluate the outcomes of a highly selected cohort of patients with LQTS managed with an observation only (intentional non-treatment) strategy.

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

Results: Among 661 patients with LQTS, 55 (8.3%) heretofore asymptomatic patients (53% female, 16 patients < 18 years of age) were managed with intentional non-therapy. Only preventative measures were advised. The mean age at diagnosis was 37.8 + 21.2 years and the mean QTc was 448 + 30 ms. None of the patients experienced a LQTS-triggered cardiac event over the mean 7.5 + 4.3 year follow-up period. Compared to the larger treated cohort, this intentionally untreated cohort was less symptomatic, older at diagnosis, and had lower resting QTc values (p < 0.0001).

Conclusion: Following 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 including asymptomatic status, older age at diagnosis, and QTc < 470 ms with excellent outcomes and a better quality of life than beta-blocked LQTS patients. LQTS patients with this low-risk profile should not receive a prophylactic ICD.

Keywords: Genetics; Ion Channels; Long QT Syndrome; Sudden Cardiac Arrest; Sudden Cardiac Death.