A short QT interval ≤320 ms had a prevalence of 0.1% among 18,825 young individuals and was associated with no deaths or syncope over a 5.3-year follow-up.
Cohort (n=18,825)
Does an isolated short QT interval predict adverse clinical outcomes in healthy young individuals?
A strict short QT interval definition of ≤320 ms is recommended in healthy young individuals to prevent overdiagnosis, as it is rare (0.1%) and associated with a benign medium-term prognosis.
OBJECTIVES: The short QT syndrome is a cardiac channelopathy characterised by accelerated repolarisation which manifests as a short QT interval on the ECG. The definition of a short QT interval is debated, ranging from <390 to ≤320 ms, and its clinical significance in healthy young individuals is unknown. We assessed the prevalence and medium-term significance of an isolated short QT interval in a diverse young British population. METHODS: Between 2005 and 2013, 18 825 apparently healthy people aged 14-35 years underwent cardiovascular evaluation with history, physical examination and ECG. QT intervals were measured by cardiologists using 4 recommended guidelines (Seattle 2013, Heart Rhythm Society 2013, European Society of Cardiology 2010 and American Heart Association 2009). RESULTS: The prevalence of a short QT interval was 0.1% (26 patients, ≤320 ms), 0.2% (44 patients, ≤330 ms), 7.9% (1478 patients, <380 ms), 15.8% (2973 patients, <390 ms). Male gender and Afro-Caribbean ethnicity had the strongest association with short QT intervals. Athletes had shorter QT intervals than non-athletes but athletic status did not predict short QT intervals. Individuals with short QT intervals ≤320 ms did not report syncope or a sinister family history, and during a follow-up period of 5.3±1.2 years, there were no deaths in this group. CONCLUSIONS: The prevalence of a short QT interval depends on the recommended cut-off value. Even at values ≤320 ms, there was an excellent medium-term prognosis among 14 people followed. We conclude that a definition of ≤320 ms is realistic to prevent overdiagnosis and excessive investigations.
Dhutia et al. (Wed,) conducted a cohort in Short QT interval (n=18,825). Short QT interval vs. Normal QT interval was evaluated on Prevalence of short QT interval and mortality. A short QT interval ≤320 ms had a prevalence of 0.1% among 18,825 young individuals and was associated with no deaths or syncope over a 5.3-year follow-up.