On-line Assessment of Left Atrial Area and Function by Automated Border Detection Echocardiography

BACKGROUND: Automated border detection (ABD) echocardiography is a convenient and objective tool in the estimation of left atrial (LA) area and function when compared to the off-line, two-dimensional echocardiographic method that requires manual tracing of the endocardial border. In addition, the applicability of the ABD system to instantaneously derive LA area and function may provide a noninvasive method to assess the diastolic interaction between the left ventricle and the left atrium. METHOD: 53 patients with a normal sinus rhythm and an apical four chamber view of LA area (in which at least 75% of the endocardium was clearly visible) were selected for this study. The on-line echocardiographic assessment of LA areas and function with automated boundary detection was performed and compared with the off-line estimation. From the instantaneous cavity area displayed by the ABD system, the extents of left atrial area decrease resulting from rapid ventricular filling (D) and atrial contraction (AC) were measured. The D/AC ratio was compared with the transmitral Doppler flow velocity E/A ratio. RESULTS: 1) The end-systolic area (ESA) and the end-diastolic area (EDA) of the left atrium, diastolic atrial emptying index (AEMI) and the systolic atrial expansion index (AEXI) with the ABD system were not different from those with the off-line, manually trace method. 2) ESA, EDA, AEMI and AEXI determined by the ABD system and the off-line method showed strong correlations (r=0.87, 0.79, 0.52 and 0.49 respectively). 3) D/AC ratio with the ABD system correlated significantly with the transmitral Doppler velocity E/A ratio (r=0.70). CONCLUSION: The ABD system may be used in the assessment of LA area and LA function and the diastolic interaction between the left atrium and the left ventricle.

On-Line Assessment of Left Ventricular Function by Automated Border Detection Echocardiography : Comparison with Gated Cardiac Blood Pool Scintigraphy

BACKGROUND: Automated border detection(ABD) is a new echocardiographic modality providing continuous on-line measurements of left ventricular(LV) cavitary ares, volume, and ejection fraction(EF) throughout the cardiac cycle. Previous study showed that LV volume and EF measurements with ABD system approximate manually traced LV volume and EF obtained with conventional 2-dimensional echocardiography. But further clinical validation needs a comparison of LV function between the ABD system and established methods. The purpose of this study is to compare EF, peak ejection rate(PER) and peak filling rate(PFR) between on-line ABD system and the gated cardiac blood pool scinitigraphy. METHOD: 27 patients with an apical 4 chamber view of LV in which at least 75% of the endocardium was clearly seen were selected for this study. They had a normal sinus rhythm and underwent echocardiographic study on the same day of or one day before gated cardiac blood pool scintigraphic study. The off-line estimation of LV volume was performed by the method of disc, after manually tracing the endocardial border on the apical 4 chamber view and EFoff was calculated. Also on that view the ABD system was turned on, and EFABD, PEABD, PEABD were calculated automatically from LV volume curve. They were compared with EFRI, PERRI, and PERRI obtained by the gated cardiac blood pool scintigraphy. RESULTS: 1) EFoff and EFABD were highly correlated with EFRI(r=0.78, 0.90 respectively : p0.05). The mean difference between PERRI and PEABD was -0.8+/-0.8EDV/sec, and the limits of agreement were -2.4~+0.8EDV/sec. PEABD were greater than PERRI(p<0.01). CONCLUSION: EF, PER, PER measurements by the ABD system and the gated cardiac blood pool scintigraphy have significant correlations. Thus ABD echocardiography is a useful method for assessement of LV function.

On-Line Assessment of Left Ventricular Volume and Ejection Fraction by the Automated Border Detection Echocardiography

BACKGROUND: The automated border detection(ABD) echocardiography has the ability of recognizing the endocardial-blood interface, and therefore, on-line estimation of the left ventricular(LV) volume every cardiac cycle. Compared with the off-line conventional 2-dimensional echocardiographic method that requires tracing the endocardial border manually, the ABDd system can be a convenient and objective method in the estimation of the LV volume and the ejection fraction(EF). The purpose of this study is to compare the LV volume and EF between the on-line ABD system and the convertional off-line echocardiographic method. METHODS: In two weeks, 83 adult patients older than 16 years of age were referred to our echocardiographic laboratory. Among these 83 patients, 64 patients who had a normal sinus rhythm were included to our study. Using the Hewlett-Packard SONOS 1500, a 2.5 MHz transducer was placed dat the cardiac apex. Patients with an apical 4 chamber view of the LV in which at least 75% of the endocardium was clearly seen were selected for study. On that view, the ABD system was turned on, and the reansmit power and the time-gain compensation controls were adjusted in order to approximate the automated border to the visually apparent endocardial surface. The LV end-diastolic volume(LVESV) and LV end-systolic volume(LVESV) were calculated by the method of disc. LVEDV, LVESV, and EF were displayed every cardiac cycle. Also the off-line estimation of the LV volume was performed by the method of disc, after manually tracing the endocardial border on the apical 4 chamber view. RESULTS: 44 patients(69%) of 64 patients had > or =75% of the LV endocardium visualized. LVEDV, LVESV, and Ef with the ABD system were highly correlated with those with the off-line, manually traced method(r=0.95, 0.8, respectively), but LVEDV and EF with toe ABD system were significantly less than those with the latter(p<0.01). The limits of agreement between tow methods(off-line, manually traced method-ABD system) were somewhat wide. Those of LVEDV, LVESV and EF were +22~-10ml(mean 6ml), +15~-14ml(mean 0.1ml), and +19~-12%(mean 3.8%), respectively. CONCLUSION: LVEDV,LVESV, and EF measurements by the ABD system and the off-line manually traced methods thve a strong correlation, The ABD system should habe clinical applications in setting, in which measurements of LV volume and Ef are important, But, the comparison with a more reliable method is necessary.