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QT interval dispersion analysis in patients with aortic valve stenosis: a prospective study
Ewa Orlowska-Baranowska1, Rafal Baranowski, Dariusz Zakrzewski
1Department of Valvular Heart Disease, The National Institute of Cardiology, Warsaw, Alpejska, Poland.
Background And Aim Of The Study:
QT interval dispersion (QTd) was analyzed in patients with aortic valve stenosis, and the relationship investigated between QTd, age, gender, hypertension, presence of significant coronary artery stenosis and left ventricular (LV) hypertrophy assessed by echocardiography. Results were also compared between survivors and patients who had cardiac arrest or died before, during or soon after cardiac surgery.
Methods:
The group comprised 535 consecutive patients (217 women, 318 men; mean age 59 +/- 11 years; range: 20-81 years) with significant aortic valve stenosis before valve replacement. The control group comprised 35 healthy subjects (12 women, 23 men; mean age 51 +/- 11 years; range: 28-74 years).
Results:
Mean QTd was 29 +/- 10 ms in controls and 59 +/- 24 ms in patients (p < 0.001). Gender had no impact on QTd. QTd was increased in men with significant coronary artery stenosis, and independently related strongly with ECG parameters (QTmax, heart rate) and weakly with age and degree of LV hypertrophy. In patients with cardiac arrest or those who died (n = 14), QTd was increased compared to that in survivors (71 +/- 22 versus 59 +/- 24 ms; p = 0.05), and QTd >70 ms was observed more frequently (p = 0.02; odds ratio 3.4, 1.16-10.0).
Conclusion:
QTd is abnormally increased in two-thirds of patients with aortic valve stenosis, and is increased in men with concomitant coronary artery disease. QTd >70 ms significantly increased the risk of cardiac arrest or death perioperatively. QTd was only weakly related with age and degree of LV hypertrophy, but QTmax and heart rate had a greater impact. QT dispersion analysis has limited clinical value in patients with aortic stenosis.