DYNAMIC ONLINE QUANTIFICATION OF BIVENTRICULAR FUNCTION WITH ACOUSTICQUANTIFICATION (AQ) - VALIDATION, REPRODUCIBILITY AND NORMAL VALUES OF A NEW ECHOCARDIOGRAPHIC APPROACH

Objectives. Acoustic quantification (AQ), a recently developed ultraso nic integrated backscatter imaging system providing on-line measuremen ts of ventricular cavity areas and their functional indexes, was valid ated in comparison to angiography and Doppler derived systolic dP/dt. Normal AQ-reference values were established. Methods and Results. 1. I n 45 patients undergoing heart catheterization, AQ derived areas in en d-diastole (EDA), end-systole (ESA) and the resulting fractional area change (FAC) in apical 2- and 4-chamber view were compared to the corr esponding biplane angiographic data. All correlations yielded signific ant values (p<0.0001; EDA: r=0.90, SEE=2.6 cm(2); ESA: r=0.91, SEE=2.2 cm(2); FAC: r=0.90, SEE = 4.1%). However, AQ-areas were underestimate d by about 25%. 2. In 36 patients with mitral regurgitation AQ-FAC and AQ derived systolic dA/dt were compared to the Doppler derived systol ic dP/dt, yielding significant correlations with r=0.91 and r=0.87; p< 0.0001. 3. In 50 healthy subjects, AQ derived EDA, ESA and FAC average d 25.7 +/- 4.9, 14.7 +/- 3.3 cm(2) and 43.2 +/- 4.8% for the left, and 17.1 +/- 3.8, 9.0 +/- 2.9 cm(2) and 47.3 +/- 9.2% for the right ventr icle. For EDA normalized peak filling (PFR) and ejection rates (PER) y ielded 2.7 +/- 0.28 and -2.4 +/- 0.42 EDA/sec for the left and 3.4 +/- 0.74 and -2.9 +/- 0.62 EDA/sec for the right ventricle. The interobse rver and day-to-day variability of AQ in healthy subjects and cardiac patients was low for EDA, ESA and FAC (<12%) and higher for PFR and PE R (<20%). Conclusion. In comparison to angiography AQ reliably quantit ates on-line left ventricular fractional area change, although AQ-area s are underestimated. AQ offers reproducible values of systolic and di astolic function and a new approach to cardiac patients.