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The relationship between diastolic function of the left ventricle and QT dispersion in patients with myocardial
P Szymański1, M Swiatkowski, J Rezler
1Department of Cardiology, Postgraduate Medical School, Grochowski Hospital, Warsaw, Poland. pszyman@polbox.com
Insights
Increased electrical dispersion, measured by QT dispersion, is linked to impaired left ventricular filling in myocardial infarction patients. This suggests repolarization abnormalities affect diastolic function.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Mechanics
Background:
- Ventricular synchronicity is crucial for both electrical and mechanical function.
- Impaired left ventricular filling can result from a lack of synchronicity.
- A direct link between electrical dispersion and impaired left ventricular filling has not been previously established.
Purpose of the Study:
- To investigate the association between QT dispersion and left ventricular filling parameters in patients with myocardial infarction.
- To determine if increased electrical dispersion correlates with abnormalities in diastolic function.
Main Methods:
- Seventy-one patients with myocardial infarction were studied.
- Echocardiographic Doppler studies and QT dispersion measurements were performed.
- Patients were categorized into high, intermediate, and low QT dispersion groups.
Main Results:
- Patients with high QT dispersion exhibited larger end-diastolic volumes compared to those with low QT dispersion (134+/-31 vs. 107+/-19 ml, P=0.049).
- A trend towards shorter E-wave deceleration time was observed in the high QT dispersion group (155+/-18 vs. 175+/-20 ms, P=0.056).
- A negative correlation was found between E-wave deceleration time and QT dispersion (r=-0.248, P=0.05).
Conclusions:
- Greater dispersion of repolarization is associated with altered left ventricular diastolic geometry and more restrictive filling patterns.
- The findings support the hypothesis that increased electrical dispersion may cause left ventricular filling abnormalities.
- Further experimental studies are warranted to confirm these associations.
Abstract:
Lack of synchronicity concerns not only the electrical but also the mechanical function of the left ventricle and causes impaired ventricular filling. To our knowledge a direct association between electrical dispersion and impairment of left ventricular filling has not been reported. The study group comprised 71 patients with myocardial infarction. Echocardiographic Doppler studies and QT dispersion measurements from standard 12-lead electrocardiograms were performed during the second week of hospitalization. The study population was divided into high, intermediate and low QT dispersion groups. Differences in the left ventricular filling parameters between high and low QT dispersion groups were assessed. Patients with high QT dispersion had larger end-diastolic volume (134+/-31 vs. 107+/-19 ml; P=0.049) and tended to have shorter E-wave deceleration time (155+/-18 vs. 175+/-20 ms; P=0.056) compared with patients with low QT dispersion. There was a negative correlation between E-wave deceleration time and QT dispersion (r=-0.248; P=0.05). We conclude that greater dispersion of repolarization is accompanied by changes in the left ventricular diastolic geometry and more 'restrictive' filling. The hypothesis that left ventricular filling abnormalities are caused by increased electrical dispersion deserves further study, especially under controlled, experimental conditions.