European Heart Journal Advance Access originally published online on January 15, 2009
European Heart Journal 2009 30(3):372-380; doi:10.1093/eurheartj/ehn585
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Ventricular transmural repolarization sequence: its relationship with ventricular relaxation and role in ventricular diastolic function
1 Division of Cardiology, Peoples Hospital, Peking University, Beijing, China
2 Lankenau Medical Center and Main Line Health Heart Center, Wynnewood, PA, USA
3 Lankenau Institute for Medical Research, Wynnewood, PA, USA
4 Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA, USA
5 The First Hospital of Xian Jiaotong University, Xian, China
Received 19 August 2008; revised 2 December 2008; accepted 12 December 2008; online publish-ahead-of-print 15 January 2009.
* Corresponding author: Main Line Health Heart Center and Lankenau Institute for Medical Research, 100 Lancaster Avenue, Wynnewood, PA 19096, USA. Tel: +1 610 645 2688, Fax: +1 610 896 0643, Email: yanganxin{at}comcast.net
Aims: We investigated the role of ventricular repolarization sequence in ventricular diastolic function.
Methods and results: Arterially perfused canine left ventricular wedge preparation with simultaneous recording of action potentials and isometric contractile force was used to establish the relationship between ventricular repolarization and relaxation sequences. An isolated rabbit working heart model was used to investigate role of ventricular repolarization sequence in ventricular diastolic function. Under controlled conditions, similar to transmural dispersion of repolarization (TDR), there existed a time difference between initiation of epicardial and endocardial relaxation (TREpi–Endo, 47.4 ± 13.9 ms) with epicardium relaxing earlier. There was a strong correlation between TDR and TREpi–Endo (r2 = 0.99, n = 5) and the interventions that changed transmural repolarization sequence led to parallel changes in transmural relaxation sequence. In isolated rabbit working hearts, reversal of the transmural repolarization sequence that manifested as negative T wave was associated with a significant increase in isovolumic relaxation time (from 49.2 ± 19.1 to 76.4 ± 12.1 ms, n = 5, P = 0.001).
Conclusion: There is a strong correlation between transmural repolarization and relaxation sequences. A positive T wave that denotes transmural repolarization sequence from epicardium to endocardium is essential for normal diastolic function of ventricle and the reversal of such sequence is associated with ventricular diastolic dysfunction.
Key Words: T Wave Ventricular repolarization Ventricular relaxation Diastolic function