Measurements of systolic time intervals using a transoesophageal pulsed echo-Doppler

Measurement of systolic time intervals (STI), an index of left ventricular (LV) systolic function, is usually labour intensive and requires considerab le expertise to perform accurately. We have evaluated the accuracy of an au tomated, continuous and non-invasive STI measurement technique using a desc ending aortic blood velocity Doppler signal obtained using a transoesophage al echo-Doppler system (TEDS) and an ECG signal. STI were measured in adult pigs using a transoesophageal probe (4 x 4 mm pulsed wave Doppler transduc er, 5-MHz frequency and a 3 x 3 mm echo transducer, 10-MHz frequency) assoc iated with an ECG recorder. Measurements were performed at baseline and aft er injection of esmolol and dobutamine. TEDS data were compared with those obtained by one-line recordings of the electrocardiogram and the central ao rtic arterial pressure wave. Similar mean values were observed for preeject ion period (PEPI), LV ejection time (LVET) and PEP/LVET with the two method s. Agreement between the methods (Bland and Altman's test) was excellent wi th 95% confidence intervals for PEP, LVET and PEP/LVET of -7.17 to +1.37 ms , -12.64 to +0.24 ms and -0.033 to +0.028, respectively. We conclude that t he combination of descending aorta blood velocity Doppler and ECG signal is an alternative technique for non-invasive and objective measurement of STI , allowing continuous monitoring of LV systolic function.