Diastolic Electromechanical Coupling: Association of the Electrocardiographic T-peak to T-end Interval with Echocardiographic Markers of Diastolic Dysfunction Andrew Sauer, MD, Jane E. Wilcox, MD, Adin-Cristian Andrei, PhD, Rod Passman, MD, MSCE, Jeffrey J. Goldberger, MD, and Sanjiv J. Shah, MD Division of Cardiology, Dept of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL Abstract Background—Electromechanical coupling, a well-described phenomenon in systolic dysfunction, has not been well studied in diastole. We hypothesized that the ECG T-peak to T-end (TpTe) interval, representing transmural dispersion of repolarization, is associated with echocardiographic markers of diastolic dysfunction (DD). Methods and Results—We performed a prospective, cross-sectional study of the association between TpTe and markers of DD in 84 consecutive, unselected patients referred for exercise echocardiography. We systematically measured TpTe on the resting electrocardiogram (ECG), and we performed comprehensive assessment of DD at rest and at peak stress. ECGs and echocardiograms were analyzed independently, blinded to each other and to all clinical data. By univariable analysis, increased TpTe was associated with older age, increased E/e’ ratio and DD (P<0.05 for all associations after correcting for multiple comparisons). Increased TpTe was inversely associated with reduced tissue Doppler e’ velocity, a marker of DD (R=-0.66, P<0.0001). This association persisted after adjusting for age, QTc, exercise-induced wall motion abnormalities, and left ventricular mass index (β=-0.41 [95% CI -0.70 to -0.12] cm/s per 10-ms increase in TpTe; P=0.006). Baseline TpTe was also independently associated with resting DD (adjusted OR=3.9 [95% CI 1.4 to 10.7]; P=0.009), and peak exercise E/e’ ratio (P<0.0001). Conclusions—Increased TpTe is associated with both resting and exercise-induced DD. Electromechanical coupling may represent a pathophysiologic link between electrical transmural dispersion of repolarization and abnormal myocardial relaxation, and may be a novel therapeutic target. Keywords diastole; ECG; echocardiography; repolarization; tissue Doppler imaging Address for correspondence: Sanjiv J. Shah, MD, FAHA, FACC, Assistant Professor of Medicine, Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, 676 N. St. Clair St., Suite 600, Chicago, IL 60611, Tel: 312-926-2926, Fax: 312-253-4470, sanjiv.shah@northwestern.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Conflict of Interest Disclosures: None. NIH Public Access Author Manuscript Circ Arrhythm Electrophysiol. Author manuscript; available in PMC 2013 June 01. Published in final edited form as: Circ Arrhythm Electrophysiol. 2012 June 1; 5(3): 537–543. doi:10.1161/CIRCEP.111.969717. NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author Manuscript