Key result
The presence of diastolic mitral annular oscillations (MAO+) was associated with a shorter time constant of isovolumic relaxation compared to MAO- (51 vs 67 ms; P<0.01).
Why the study?
Does the presence of diastolic mitral annular oscillations indicate superior left ventricular relaxation in subjects with normal ejection fraction?
Observational (n=55)
Does the presence of diastolic mitral annular oscillations indicate superior left ventricular relaxation in subjects with normal ejection fraction?
The absence of early diastolic mitral annular oscillations on tissue Doppler imaging is a simple marker for relaxation-related diastolic dysfunction in patients with normal ejection fraction.
Answers are grounded in this paper and cite their sources.
Supports MAO+ as potential TDI marker of faster relaxation in normal EF; hypothesis-generating, requires prospective validation before clinical use.
Although Doppler tissue imaging frequently indicates the presence of mitral annular oscillations (MAO) following the E' wave (E'' wave, etc.), only recently was it shown that annular "ringing" follows the rules of damped harmonic oscillatory motion. Oscillatory model-based analysis of E' and E'' waves provides longitudinal left ventricular (LV) stiffness (k'), relaxation/viscoelasticity (c'), and stored elastic strain (x(o)') parameters. We tested the hypothesis that presence (MAO(+)) vs. absence (MAO(-)) of diastolic MAO is an index of superior LV relaxation by analyzing simultaneous echocardiographic-hemodynamic data from 35 MAO(+) and 20 MAO(-) normal ejection fraction (EF) subjects undergoing cardiac catheterization. Echocardiographic annular motion and transmitral flow data were analyzed with a previously validated kinematic model of filling. Invasive and noninvasive diastolic function (DF) indexes differentiated between MAO(+) and MAO(-) groups. Specifically, the MAO(+) group had a shorter time constant of isovolumic relaxation [tau; 51 (SD 13) vs. 67 (SD 27) ms; P<0.01] and isovolumic relaxation time [63 (SD 16) vs. 82 (SD 17) ms; P<0.001] and greater ratio of peak E-wave to peak A-wave velocity [1.19 (SD 0.31) vs. 0.97 (SD 0.31); P<0.05]. The MAO(+) group had greater peak lateral mitral annulus velocity [E'; 17.5 (SD 3.1) vs. 13.5 (SD 3.8) cm/s; P<0.001] and LVEF [71.2 (SD 7.5)% vs. 65.4 (SD 9.1)%; P<0.05] and lower heart rate [65 (SD 9) vs. 74 (SD 9) beats/min, P<0.001]. Additional conventional and kinematic modeling-derived indexes were highly concordant with these findings. We conclude that absence of early diastolic MAO is an easily discernible marker for relaxation-related diastolic dysfunction. Quantitation of MAO via stiffness and relaxation/viscoelasticity parameters facilitates quantitative assessment of regional (i.e., longitudinal) DF and may improve diagnosis of diastolic dysfunction.
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Riordan et al. (2007) conducted an observational in Normal ejection fraction (n=55). Presence of diastolic mitral annular oscillations (MAO+) vs. Absence of diastolic mitral annular oscillations (MAO-) was evaluated on Time constant of isovolumic relaxation (tau) (p=<0.01). The presence of diastolic mitral annular oscillations (MAO+) was associated with a shorter time constant of isovolumic relaxation compared to MAO- (51 vs 67 ms; P<0.01).
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