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QT interval as a cardiac risk factor in a middle aged population
J Karjalainen1, A Reunanen, P Ristola
1Central Military Hospital, Helsinki, Finland.
Heart (British Cardiac Society)
|June 1, 1997
Summary
Prolonged QT interval predicts cardiac mortality in middle-aged men with cardiovascular disease. Shortened QT interval indicates death risk in men who smoke and have heart disease.
Area of Science:
- Cardiology
- Preventive Medicine
- Public Health
Background:
- The QT interval on an electrocardiogram (ECG) reflects ventricular repolarization.
- Assessing cardiac risk factors is crucial for preventive cardiology.
Purpose of the Study:
- To determine the prognostic value of the QT interval as a cardiac risk factor in a middle-aged population.
- To investigate the association between QT interval variations and cardiovascular mortality.
Main Methods:
- A longitudinal study evaluated 5598 men and 5119 women over 23 years.
- A nomogram was developed to correct the QT interval for heart rate (QTNc) in men and women separately.
Main Results:
- QT interval prolongation (QTNc) correlated with hypertension and cardiovascular disease signs.
- QTNc shortening was linked to smoking.
- In men with heart disease, prolonged QTNc predicted increased risk of sudden death, cardiovascular mortality, and all-cause mortality.
- In men who smoked with heart disease, shortened QTNc predicted cardiovascular death.
- In women and healthy men, the predictive value of QT interval variations for mortality was weaker.
Conclusions:
- Prolonged QT interval is a significant predictor of cardiac mortality in middle-aged men with existing cardiovascular disease.
- Shortened QT interval predicts mortality in smoking men with heart disease.
- The predictive value of QT interval variations for mortality is less pronounced in women and healthy men, potentially indicating subclinical disease.