Mechanism of right precordial ST-segment elevation in structural heart disease: Excitation failure by current-to-load mismatch

Mark G. Hoogendijk*, Mark Potse, André C. Linnenbank, Arie O. Verkerk, Hester M. den Ruijter, Shirley C.M. van Amersfoorth, Eva C. Klaver, Leander Beekman, Connie R. Bezzina, Pieter G. Postema, Hanno L. Tan, Annette G. Reimer, Allard C. van der Wal, Arend D.J. ten Harkel, Michiel Dalinghaus, Alain Vinet, Arthur A.M. Wilde, Jacques M.T. de Bakker, Ruben Coronel

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Background: The Brugada sign has been associated with mutations in SCN5A and with right ventricular structural abnormalities. Their role in the Brugada sign and the associated ventricular arrhythmias is unknown. Objective: The purpose of this study was to delineate the role of structural abnormalities and sodium channel dysfunction in the Brugada sign. Methods: Activation and repolarization characteristics of the explanted heart of a patient with a loss-of-function mutation in SCN5A (G752R) and dilated cardiomyopathy were determined after induction of right-sided ST-segment elevation by ajmaline. In addition, right ventricular structural discontinuities and sodium channel dysfunction were simulated in a computer model encompassing the heart and thorax. Results: In the explanted heart, disappearance of local activation in unipolar electrograms at the basal right ventricular epicardium was followed by monophasic ST-segment elevation. The local origin of this phenomenon was confirmed by coaxial electrograms. Neither early repolarization nor late activation correlated with ST-segment elevation. At sites of local ST-segment elevation, the subepicardium was interspersed with adipose tissue and contained more fibrous tissue than either the left ventricle or control hearts. In computer simulations entailing right ventricular structural discontinuities, reduction of sodium channel conductance or size of the gaps between introduced barriers resulted in subepicardial excitation failure or delayed activation by current-to-load mismatch and in the Brugada sign on the ECG. Conclusion: Right ventricular excitation failure and activation delay by current-to-load mismatch in the subepicardium can cause the Brugada sign. Therefore, current-to-load mismatch may underlie the ventricular arrhythmias in patients with the Brugada sign.

Original languageEnglish
Pages (from-to)238-248
Number of pages11
JournalHeart Rhythm
Volume7
Issue number2
DOIs
Publication statusPublished - 2010

Bibliographical note

Funding Information:
The first two authors contributed equally to this work. This study was supported by The Netherlands Heart Foundation Grant 2005T024 to Dr. Bezzina, Grant 2003T302 to Dr. Wilde, Grant 2005B092 to Drs. de Bakker and Linnenbank, and Grant 2008B062 to Dr. Coronel; the Interuniversity Cardiology Institute of The Netherlands ; the Royal Netherlands Academy of Arts and Sciences to Dr. Tan; the Netherlands Organisation for Scientific Research Grant ZonMW-VICI 918.86.616 to Dr. Tan; and the Réseau Québécois de Calcul de Haute Performance (RQCHP) .

Research programs

  • EMC COEUR-09

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