Arrhythmias & electrophysiologyCohort study
A population-based study of trends in cardiac arrest and sudden death owing to long QT syndrome
- population-based study
- national long QT syndrome (LQTS) registry
Authors' conclusion
Decreasing rates of LQTS detection in recent years suggest that most cases have been discovered in New Zealand. Decreasing cardiac arrest and sudden death owing to LQTS is likely related to the success of the overall program.
Study context
- Population
- Registry participants who underwent genetic testing for LQTS presenting between 2000 and 2023, New Zealanddiagnosed as having LQTS, 378 probands
- Participants
- 915 participants
Main finding
As reported in the abstract
Presentation of probands
- Mean corrected QT interval
- 512 ± 52 ms
- Sudden cardiac death
- 26 of 378; 7%
- Resuscitated cardiac arrest (RSCA)
- 82; 21%
- Syncope or seizure
- 122; 32%
- Incidental/other
- 148; 40%
Observational data: associations, not effects.
Further findings
Causative genetic variants in probands
- Causative genetic variants found
- 165 of 378 probands (44%)
- KCNQ1, of the 165 with variants
- 98 KCNQ1 (59%)
- KCNH2, of the 165 with variants
- 41 KCNH2 (25%)
- SCN5A, of the 165 with variants
- 7 SCN5A (4%)
- Other genes, of the 165 with variants
- 19 other genes (12%)
Therapy
- On therapy
- 593 of 915 participants (65%)
- Beta blocker
- 565; 62%
- Implantable cardioverter-defibrillator
- 134; 16%
- Left cardiac sympathetic denervation
- 69; 8%
Events during follow-up · median 12 years
- Likely arrhythmic deaths
- 3 likely arrhythmic deaths (0.3%)
- Appropriate implantable cardioverter-defibrillator shocks
- 23 appropriate implantable cardioverter-defibrillator shocks (3%)
Detections of LQTS/population
- 2000
- 0.5 of 100,000
- 2009
- 1.6 of 100,000
- 2023
- 0.4 of 100,000
Presentation with RSCA · from 2007
- Decreased per year
- 10%/y
Presentation with death · from 2014
- Decreased per year
- 22%/y
- P
- P = 0.026
- No deaths from 2019 to 2023
Original publication
A population-based study of trends in cardiac arrest and sudden death owing to long QT syndrome. Heart Rhythm. Published 26 February 2026. doi:10.1016/j.hrthm.2026.02.033
Summarised from the published abstract; every number is checked against it