Importance of left ventricular activation in determining myocardial performance (Tei) index: comparison with total isovolumic time.
BACKGROUND
The Tei index is commonly used as a measure of "combined systolic and diastolic function". A sensitive and specific index of intrinsic myocardial contraction and relaxation would be independent of abnormal activation. We aimed to determine whether the Tei index fulfils this criterion in patients with normal activation or left bundle branch block (LBBB), normal or dilated left ventricular (LV) cavities, with or without coronary artery disease (CAD).


METHODS
We studied 32 controls and 124 patients; 49 had CAD and normal LV size (11 LBBB), 27 had non-ischaemic dilated cardiomyopathy (DCM, 11 LBBB), and 48 had ischaemic DCM (17 LBBB). Tei index (isovolumic contraction time+isovolumic relaxation time/ejection time) and total isovolumic time (t-IVT: [60-(total ejection time+total filling time]) were measured using Doppler echocardiography.


RESULTS
Tei index and t-IVT were prolonged in LBBB (by 0.6 and 9.1 s/min, P<0.001). T-IVT identified LBBB with greater predictive accuracy than Tei index (sensitivity 97% vs. 90%, specificity 93% vs. 91%, P<0.05). Tei index and t-IVT were also prolonged in DCM (by 0.2 and 3.1 s/min, both P<0.001). Although Tei index identified DCM with sensitivity 71%, this fell to 53% when LBBB was excluded (P<0.05). CAD had no effect on Tei index or t-IVT.


CONCLUSIONS
The Tei index is not a measure of intrinsic myocardial systolic and diastolic function, since its main determinant is ventricular activation rather than cavity size. T-IVT, however, is more sensitive to activation, is unrelated to cavity size or CAD, and may thus be a more accurate measure of the mechanical consequences of ventricular activation in a variety of cardiac conditions.
Duncan
Alison M
AM
Department of Echocardiography, The Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK. a.duncan@ic.ac.uk
Francis
Darrel P
DP
Henein
Michael Y
MY
Gibson
Derek G
DG
D000368:Aged; D000704:Analysis of Variance; D002037:Bundle-Branch Block / Q000175:diagnosis*; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis*; D016022:Case-Control Studies; D003327:Coronary Disease / Q000175:diagnosis; D015150:Echocardiography, Doppler; D005260:Female; D006334:Heart Function Tests / Q000379:methods*; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis*