Electromechanical window negativity in genotyped long-QT syndrome patients: Relation to arrhythmia risk

Rachel M A Ter Bekke, Kristina H. Haugaa, Arthur Van Den Wijngaard, J. Martijn Bos, Michael John Ackerman, Thor Edvardsen, Paul G A Volders

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

Aim Prolonged and dispersed left-ventricular (LV) contraction is present in patients with long-QT syndrome (LQTS). Electrical and mechanical abnormalities appear most pronounced in symptomatic individuals. We focus on the electromechanical window(EMW; duration of LV-mechanical systole minus QT interval) in patients with genotyped LQTS. Profound EMW negativity heralds torsades de pointes in animal models of drug-induced LQTS. Methods and results We included 244 LQTS patients from three centres, of whom 97 had experienced arrhythmic events. Seventy-six matched healthy individuals served as controls. QT interval was subtracted from the duration of Q-onset to aortic-valve closure (QAoC) midline assessed non-invasively by continuous-wave echocardiography, measured in the same beat. Electromechanical window was positive in controls but negative in LQTS patients (22 ± 19 vs. 43 ± 46 ms; P < 0.0001), being even more negative in symptomatic than event-free patients (67 ± 42 vs. 27 ± 41 ms; P < 0.0001). QT, QTc, and QAoC were longer in LQTS subjects (451 ± 57, 465 ± 50, and 408 ± 37 ms, P < 0.0001). Electromechanical window was a better discriminator of patients with previous arrhythmic events than resting QTc (AUC 0.77 (95% CI, 0.71-0.83) and 0.71 (95% CI, 0.65-0.78); P = 0.03). In multivariate analysis, EMW predicted arrhythmic events independently of QTc (odds ratio 1.25; 95% CI, 1.11-1.40; P = 0.001). Adding EMW to QTc for risk assessment led to a net reclassification improvement of 13.3% (P = 0.03). No EMW differences were found between the three major LQTS genotypes. Conclusions Patients with genotype-positive LQTS express EMW negativity, which is most pronounced in patients with documented arrhythmic events.

Original languageEnglish (US)
Pages (from-to)179-186
Number of pages8
JournalEuropean Heart Journal
Volume36
Issue number3
DOIs
StatePublished - Jan 14 2015

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Keywords

  • Arrhythmia
  • Echocardiography
  • Ion channels
  • Long-QT syndrome
  • Sudden death

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

Cite this

Ter Bekke, R. M. A., Haugaa, K. H., Van Den Wijngaard, A., Bos, J. M., Ackerman, M. J., Edvardsen, T., & Volders, P. G. A. (2015). Electromechanical window negativity in genotyped long-QT syndrome patients: Relation to arrhythmia risk. European Heart Journal, 36(3), 179-186. https://doi.org/10.1093/eurheartj/ehu370