Reduction of the QT interval dispersion after aortic valve replacement reflects changes in electrical function rather...

Area of Science:

• Cardiology
• Cardiac Electrophysiology
• Cardiac Surgery

Background:

• Aortic stenosis is a significant cardiovascular condition requiring intervention.
• QT dispersion (QTd) is an electrocardiographic marker of repolarization heterogeneity, potentially linked to adverse cardiac events.
• Aortic valve replacement (AVR) is the standard treatment for severe aortic stenosis.

Purpose of the Study:

• To analyze factors associated with changes in QT dispersion (QTd) following aortic valve replacement (AVR) in patients with aortic stenosis.
• To investigate the relationship between structural cardiac remodeling and electrical repolarization changes post-AVR.

Main Methods:

• Prospective study of 121 patients with significant aortic valve stenosis undergoing AVR.
• Collection of clinical, echocardiographic, and electrocardiographic data before and at least 16 months after AVR.
• Measurement of QT dispersion (QTd) using standard ECG.

Main Results:

• A significant decrease in mean QTd was observed post-AVR (from 60 ± 24 ms to 54 ± 19 ms).
• QTd reduction was noted in 27% of patients, irrespective of significant reduction in left ventricular hypertrophy.
• Multivariate analysis revealed a weak association between QTd reduction and decreased left ventricular mass index (LVMI) or wall thickness, but a stronger correlation with changes in T-wave amplitude in lead V5 (p=0.004).

Conclusions:

• Aortic valve replacement leads to a reduction in QT dispersion, particularly in patients with initially elevated QTd.
• The observed QTd reduction post-AVR is primarily related to alterations in cardiac electrical function, specifically T-wave amplitude changes.
• These findings suggest that post-AVR QTd changes reflect improved electrical stability rather than solely structural cardiac remodeling.