A NEW QUANTITATIVE METHOD FOR EVALUATION OF SYSTOLIC AND DIASTOLIC
MYOCARDIAL FUNCTION USING HIGH FRAME RATE DIGITAL ECHOCARDIOGRAPHY
AND VARIABLE REFERENCE M-MODE. RA. Phillips*, MJ. West, DJ. Burstow. University of Queensland and The Prince
Charles Hospital, Brisbane, Australia. Background: New pixel reconstructive software can synthesise
angle and translation corrected left ventricular M-Mode sections
from which direct temporal and spatial measurements can provide
parameters of systolic and diastolic myocardial function. Method: High frame rate (120±14fps) 2D parasternal
long axis cycles were acquired from eighty one normal subjects and
a Variable Reference (VR) M-Mode was synthesised providing a basal
anterior septal (BAS) and basal posterior (BP) myocardial segmental
section. From the onset of the QRS complex the timing of segmental
end systole (sys), end early diastole (ed) and end diastole (d)
was measured from the endocardial surface. Myocardial thickness
(T) at each time was also measured and fractional wall thickening
(FWT), duration (D), and mean rates of thickening and thinning were
derived for sys, ed and d. Segmental activation delay (SAD)
was defined as the time between electrical ventricular activation
and the onset of mechanical segmental systole. Reproducibility
was tested by comparison of independent blinded observations. Results: Temporal
parameters (ms) Segment SAD Dsys Ded Dd BAS
(n=81) 44±19 260±32 83±35 570±170 BP
(n=81) 84±21 280±32 110±29 550±170 Spatial
parameters (cms) Segment Tdias Tsys Ted FWT% BAS
(n=81) 0.79±0.14 1.20±0.14 0.84±0.16 50.56±13.47 BP
(n=81) 0.78±0.13 1.30±0.19 0.82±0.13 67.86±16.27 Derived
parameters - Rates of thickening and thinning (cm/s) Segment Sys ed d BAS
(n=81) 1.56±0.47 5.18±2.89 0.75±0.28 BP
(n=81) 1.90±0.45 4.69±2.20 1.02±0.33 Reproducibility was good (r>0.824,
p<0.0005) with superior correlation of temporal measurements. Conclusions: Spatial and temporal mapping of VR M .Modes derived from
high frame rate digital echocardiograms is feasible and may provide new
insights into myocardial systolic and diastolic physiology. This study defines normal adult values for
these new quantitative parameters and will allow application of this technique
to various myocardial pathologies.
