Arrhythmias & electrophysiology
The clinical and electrocardiographic phenotype of patients with genotype-negative long QT syndrome
Authors' conclusion
Genotype-negative LQTS accounted for < 2% of our cohort, highlighting diagnostic and management challenges.
Study context
- Population
- Patients with Long QT syndrome (LQTS) seen at Mayo Clinic (2000–2024)
- Participants
- 1,829 patients
- Outcome
- Prevalence and clinical characteristics of phenotype-positive, genotype-negative LQTS
Methodological detailssingle-centre
- Single-centre
Main finding
As reported in the abstract
Genotype-negative LQTS
Pathogenic or likely pathogenic variants
1706
93%
Upgraded clinical variants of uncertain significance
95
5%
Negative genetic tests
32
1.7%
Genetic cause identified by next-generation sequencing (17 tested)
6
0.3% of the total
Observational data: associations, not effects.
Further findings
Characteristics of remaining genotype-negative patients (n = 26)
- Mean age at diagnosis
- 25 ± 15 years
- Women
- 76%
- Average initial corrected QT
- 498 ± 41 ms
- Cardiac events prior to diagnosis
- 14 (53%)
- Received ICD
- 11 (44%)
- Mean follow-up
- 8 ± 7 years
Original publication
The clinical and electrocardiographic phenotype of patients with genotype-negative long QT syndrome. Heart Rhythm. Published 29 May 2025. doi:10.
Summarised from the published abstract; every number is checked against it