Ventricular transmural repolarization sequence: its relationship with ventricular relaxation and role in ventricular
Tian Gang Zhu1, Chinmay Patel, Seth Martin
1Division of Cardiology, People's Hospital, Peking University, Beijing, China.
European Heart Journal
|January 17, 2009
Summary
Normal ventricular diastolic function requires a specific repolarization sequence. Reversing this sequence, indicated by a negative T wave, impairs relaxation and leads to diastolic dysfunction.
Area of Science:
- Cardiovascular Physiology
- Cardiac Electrophysiology
Background:
- Ventricular diastolic function is crucial for cardiac health.
- The sequence of ventricular repolarization may influence diastolic function.
Purpose of the Study:
- To investigate the relationship between ventricular repolarization sequence and diastolic function.
- To determine if alterations in repolarization sequence impact ventricular relaxation.
Main Methods:
- Used arterially perfused canine left ventricular wedge preparations to record action potentials and contractile force.
- Employed an isolated rabbit working heart model to assess diastolic function under controlled conditions.
- Measured transmural dispersion of repolarization (TDR) and transmural relaxation time (TR(Epi-Endo)).
Main Results:
- A time difference in relaxation between epicardium and endocardium (TR(Epi-Endo)) was observed, with epicardium relaxing earlier.
- Strong correlation found between TDR and TR(Epi-Endo) (r(2) = 0.99).
- Reversal of repolarization sequence (negative T wave) significantly increased isovolumic relaxation time (P = 0.001).
Conclusions:
- A strong correlation exists between transmural repolarization and relaxation sequences.
- A normal, epicardium-to-endocardium repolarization sequence (positive T wave) is vital for normal ventricular diastolic function.
- Reversal of this sequence is linked to ventricular diastolic dysfunction.
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