Prolonged corrected QT interval is predictive of future stroke events even in subjects without ECG-diagnosed left...

Area of Science:

• Cardiology
• Neurology
• Public Health

Background:

• The corrected QT (QTc) interval on an electrocardiogram (ECG) reflects ventricular repolarization duration.
• Left ventricular hypertrophy (LVH) is a known cardiovascular risk factor.
• The independent association between QTc interval and stroke risk, particularly in the absence of LVH, requires further investigation.

Purpose of the Study:

• To determine if a prolonged QTc interval, with or without ECG-diagnosed left ventricular hypertrophy (ECG-LVH), increases stroke risk.
• To assess the independent contribution of QTc prolongation to stroke risk.
• To evaluate stroke risk across different combinations of QTc interval status and ECG-LVH.

Main Methods:

• A cohort study involving 10,643 subjects.
• Assessment of prolonged QTc interval (≥440 ms in men, ≥460 ms in women) and ECG-LVH (Cornell product ≥244 mV×ms).
• Multivariate-adjusted Cox proportional hazards analysis to evaluate stroke risk over a median follow-up of 128.7 months.

Main Results:

• A prolonged QTc interval was associated with an increased risk of stroke (HR, 2.13).
• This association remained significant even after adjusting for ECG-LVH (HR, 1.71).
• Subjects with a prolonged QTc interval but without ECG-LVH showed a significantly higher stroke risk (HR, 2.70) compared to those with neither condition.

Conclusions:

• Prolonged QTc interval is an independent risk factor for stroke.
• The association between prolonged QTc interval and stroke risk is evident even in individuals without ECG-diagnosed left ventricular hypertrophy.
• ECG findings of prolonged QTc interval warrant attention for stroke risk stratification in the general population.