Measurement of Cardiac Time Intervals by Doppler Tissue M-Mode Imaging of the Anterior Mitral Leaflet Jesper Kjaergaard, MD, Christian Hassager, MD, DMSc, Jae K. Oh, MD, FACC, Jens H. Kristensen, MD, Jens Berning, MD, and Peter Sogaard, MD, DMSc, Rochester, Minnesota; and Copenhagen, Aalborg, and Hellerup, Denmark Objective: We sought to evaluate a new method of measuring cardiac time intervals from Doppler tis- sue imaging (DTI) of the anterior leaflet of the mitral valve. Background: For a reliable analysis of the regional cardiac performance by DTI, a reference of time intervals of global cardiac events in the same cardiac cycle and based on the same imaging modality is required to reduce measurement error. Methods: We conducted a comparison of the mea- surements of isovolumic contraction and relaxation time and left ventricular (LV) ejection time by DTI M-mode analysis of the anterior mitral leaflet and the traditional approach based on spectral Doppler recordings. The measurements were done in 20 control subjects and 40 patients with cardiac dis- eases known to affect cardiac time intervals: heart failure, aortic stenosis, and essential hypertension with LV hypertrophy. Results: Mean difference in milliseconds (95% lim- its of agreement) of measurements were not differ- ent overall (0.20 [10.58; 10.18], 1.95 [16.66; 12.76], 1.48 [8.34; 11.34], and 0 [0.06; 0.07] for isovolumic contraction time, LV ejection time, iso- volumic relaxation time, and calculated index of myocardial performance, respectively). Intraob- server variability was low. Analysis of patients with different categories of cardiac diseases confirmed the expected values for time intervals and index of myocardial performance. Conclusions: Measurement of isovolumic periods and LV ejection time was feasible and reliable by DTI M-mode analysis of the anterior mitral valve leaflet. The DTI method can, therefore, be used for obtain- ing information of global events in the cardiac cycle from the same heart beat as used for analysis of regional cardiac performance. (J Am Soc Echocar- diogr 2005;18:1058-1065.) Reliable measurement of cardiac time intervals is of increasing interest in the assessment of cardiac function. 1 The Tei index of myocardial performance (IMP) is based on measurement of the cardiac time intervals by spectral Doppler echocardiography and has been shown to be a combined index of systolic and diastolic cardiac function. 2 Based on noninva- sive methods it represents a unique way of express- ing global cardiac performance, independent of heart rate and blood pressure. 2,3 However, IMP by spectral Doppler requires the measurement of several cardiac time intervals such as left ventricular (LV) outflow tract ejection time (ET) and isovolumic periods. The combined isovolumic contraction time (IVCT) and isovolu- mic relaxation time (IVRT) is obtained by subtract- ing LV outflow tract ET from the interval between mitral valve closure and mitral valve opening. These calculations require at least two separate pulsed wave Doppler examinations from different cardiac cycles. This makes the spectral Doppler IMP subject to potential variation with heart rate, a problem commonly addressed by averaging over 3 or more beats. 4 With novel echocardiographic modalities such as Doppler tissue imaging (DTI), new and innovative possibilities in assessment of regional myocardial performance have emerged 5,6 and identification of a measure of global performance as an inherent, indi- vidual reference is desirable. To minimize error this reference should be based on the same modality as used for regional measurements and ideally global From the Division of Cardiovascular Diseases and Internal Medi- cine, Mayo Clinic College of Medicine, Rochester; and Depart- ments of Cardiology at University Hospital, Rigshospitalet, Copenhagen (C.H.), University Hospital of Aalborg (J.H.K., J.B.), and University Hospital of Gentofte, Hellerup (P.S.). Data collection supported in part by a research grant from Servier, Denmark (Dr Sogaard). Research fellowship (Dr Kjaergaard) sup- ported by grant No. 03-2-3-46A-22112 from the Danish Heart Foundation. Reprint requests: Peter Sogaard, MD, DMSc, Department of Cardiology P, University Hospital of Gentofte, DK-2900 Hellerup, Denmark (E-mail: psogaard@dadlnet.dk). 0894-7317/$30.00 Copyright 2005 by the American Society of Echocardiography. doi:10.1016/j.echo.2005.03.043 1058