Reflected High-intensity Motion Signals: Can This Ultrasound Phenomenon Be Used for Assessment of Left Ventricular Function?

Abstract

In this pioneer study, we aimed to evaluate the diagnostic role of reflected high-intensity motion signals (RIMS) in the assessment of left ventricular (LV) systolic and diastolic function and to analyze the reproducibility of RIMS. RIMS are also known under the name of "spectral Doppler artifacts" and to date have been attributed only to the category of useless noises. The value of RIMS in the evaluation of LV function was analyzed in 173 subjects (57 healthy volunteers and 116 patients with chronic coronary and myocardial diseases and arterial hypertension). The level of intra- and inter-observer reproducibility of RIMS was assessed according to the Bland-Altman method in 29 subjects. To record RIMS by conventional pulsed wave Doppler, an apical 4-chamber view was used and the sample volume was placed 3 - 4 cm laterally to the left border of the mitral annulus in projection of the pulmonary tissue. Three components of RIMS are visualized with each cardiac cycle: one systolic (Sa) component and two diastolic (Ea and Aa) components. We have found that RIMS registration did not depend on the quality of LV visualization. In patients with adequate visualization of the cardiac structures and in "difficult" patients with poor LV visualization, RIMS recordings were visually equal. In our study, correlations between LV ejection fraction (EF) and Sa and Aa were found; the cutoff value of Sa < or = 13 cm/s and Aa < or = 15 cm/s separated patients with EF < or = 40 % from other subjects with a sensitivity of 88.2 % and 94.1 % and a specificity of 93.0 % (p <.0001) and 76.9 % (p <.0001), respectively. It was shown that RIMS correlate with the LV diastolic function. The Ea cutoff value of < or = 20 cm/s distinguished subjects with a normal diastolic function from patients with a sensitivity of 88.6 % and a specificity of 80.0 % (p <.0001); the cutoff values of Sa < or = 10 cm/s and Aa < 12 cm/s separated patients with a Grade 4 diastolic dysfunction (according to Canadian consensus recommendations) from other subjects with a sensitivity of 81.8 % and 90.9 %, and a specificity of 98.1 % (p <.0001) and 91.8 % (p <.0001), respectively. The combined evaluation of traditional transmitral E/A ratio and RIMS components allow differentiating of all standard stages of LV diastolic dysfunction in an easy and effective way. The level of intra- and inter-observer reproducibility of RIMS appeared to be acceptable. 1. Systolic and late diastolic components of RIMS correlate with LV global systolic function, and all components of RIMS correlate with LV global diastolic function; 2. The reproducibility of RIMS components is at an acceptable level; 3. Combined analysis of transmitral E/A ratio and RIMS components can become a promising approach for easy and effective separation of patients with different grades of diastolic dysfunction.