Quantitation of basal dyssynchrony and acute resynchronization from left or biventricular pacing by novel echo-contrast variability imaging
Miho Kawaguchi, MD*,
Taizo Murabayashi, MD, PhD*,
Barry J. Fetics, MSE*,
Gregory S. Nelson, PhD*,
Hisanori Samejima, MD, PhD*,
Erez Nevo, MD, DSc* and
David A. Kass, MD*,*
* Division of Cardiology, Department of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
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Figure 2 Determination of regional fractional area change (RFAC). (A) A pie-shaped sector is drawn from the centroid of each contour to 15° arcs on the contour. Sector area is determined and referenced to its value at end-diastole (corresponding to QRS peak) to derive RFAC. (B) Example of RFAC versus time from end-diastole to end-systole, for an example sector.
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Figure 3 Representative four-chamber cardiac variability imaging (CVI) images generated with stimulation (left ventricular [LV] only in this case) turned on or off. With pacing suspended, there was septal-apical dyskinesis characterized by early shortening followed by late systolic stretch. With LV lateral wall stimulation, dyskinesis declined and overall ejection improved. The radial lines on the initial still image delineate the sectors within the septum and lateral wall that were used for subsequent regional fractional area change analysis (see Fig. 4). For the accompanying video to Figure 3, please see the June 19th issue of JACC at http://www.cardiosource.com/library/journals/journal/suppdata?acronym=JAC&pii=s0735109702018831&filename=Figure_3.avi
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Figure 4 (A) Regional fractional area change (RFAC) maps for each sector corresponding to the cardiac variability imaging images shown in Figure 3. The location of each segment is identified in the prior figure. In normal sinus rhythm (stimulation off), septal contraction often displayed early negative RFAC followed by late positive deflection (expansion) and lateral contraction showed the opposite pattern. Left ventricular pacing improved motion in the septum toward normal but had minimal effects on lateral wall motion. (B) Mean results for maximal RFAC and mean rate of change in septal and lateral regions with stimulation activated or turned off. See text for details.
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Figure 5 Quantitation of ventricular mechanical dyssynchrony. (A) Spatial dyssynchrony; a coefficient of variation of regional fractional area change (RFAC) measured at the time of maximal negative RFAC; (B) temporal dyssynchrony; a coefficient of variation of time at maximal negative RFAC; left ventricular (LV) or biventricular (BiV) pacing significantly improved both measures in nearly all patients. (C) Improvement in EF induced by LV or BiV pacing. (D) There was a negative correlation between the extent of spatial dyssynchrony and systolic function, and most all subjects showed a shift upward and to the left with active pacing; p = 0.005, n = 9. EF = ejection fraction.
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