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Use of monophasic action potentials to evaluate postpacing T wave changes
1Department of Internal Medicine, Fukuoka University School of Medicine, Japan.
Cardiology
|January 1, 1993
Summary
Post-pacing T wave changes in dogs reflect altered ventricular repolarization. Myocardial cells appear to retain a memory of abnormal repolarization following pacing, impacting action potential duration.
Area of Science:
- Cardiovascular Physiology
- Electrophysiology
Background:
- T wave changes on electrocardiograms can indicate underlying repolarization abnormalities.
- Monophasic action potentials (MAPs) provide detailed information about cardiac repolarization.
Purpose of the Study:
- To investigate the relationship between postpacing T wave alterations and ventricular monophasic action potential durations (MAPD90) in dogs.
- To determine if myocardial cells retain a memory of pacing-induced repolarization changes.
Main Methods:
- Monophasic action potentials were recorded from the right and left ventricles of dogs before and after cessation of pacing.
- The duration of the monophasic action potential to 90% repolarization (MAPD90) was calculated.
- Electrocardiographic T wave changes and QT intervals were monitored.
Main Results:
- Pacing induced T wave abnormalities and prolonged QT intervals in limb leads.
- Right ventricular pacing prolonged right ventricular MAPD90, while left ventricular pacing prolonged left ventricular MAPD90.
- MAPD90 at the pacing site progressively increased over time, indicating a sustained effect.
Conclusions:
- Postpacing T wave changes are associated with alterations in ventricular repolarization dynamics.
- Myocardial cells exhibit a 'memory' of abnormal repolarization induced by pacing.
- These findings have implications for understanding cardiac electrophysiology and pacing-related effects.