(Circulation. 1999;99:2708.)
© 1999 American Heart Association, Inc.
Images in Cardiovascular Medicine |
Left Ventricular Electromechanical Mapping of Myocardial Ischemia
From the Cardiology Research Foundation, Washington Hospital Center, Washington, DC.
Anovel technology for mapping the left ventricle (LV) has been derived from a new diagnostic and guidance-navigational system (Biosense). This system uses a low-intensity magnetic field energy source and sensor-tipped catheters to locate catheter position in 3D space and reconstructs online, color-coded electromechanical maps of the LV without using fluoroscopy. Such a system has been used in the electrophysiology field to diagnose, locate, and treat arrhythmogenic foci. This system also allows distinction of normal from infarcted or ischemic myocardium, based on intracardiac recording of voltage potentials, and the mechanical map can provide global and regional LV contractility data.
We used the Biosense system to map the LV of a 75-year-old woman
with chronic refractory angina pectoris and no previous
myocardial infarction. She did, however, have prior
coronary bypass surgery and currently has reversible
inferior and posterolateral perfusion defects in
nuclear imaging study. Figures 1
and 2 present right and left
anterior oblique LV projections, respectively. Panels A are
electroanatomic maps show- ing a normal pattern of intracardiac
electrical activation sequence ranging from –35 ms (color-coded as
red) in the septal zone to +10 ms (blue-purple) in the
posterolateral area. Panels B are voltage maps (unipolar
recording) showing high (>25 mV) voltage potentials
(blue-purple) through the LV, except for a zone of
physiological reduced voltage (<10 mV, red)
in the mitral annulus (1B, arrow). Panels C are local shortening maps
detecting the extent of LV contractility, with
an extensive hypokinetic zone (local shortening <6%, red) in the
inferior and posterolateral walls (arrows). A mechanical
impairment (C) within an area of intact electrical activity (B)
represents an electromechanical dissociation, most
likely due to severe chronic ischemia or hibernating
myocardium, as shown in this
example.
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Footnotes
Reprint requests to Ran Kornowski, MD, Cardiology Research Foundation, Washington Hospital Center, 110 Irving St, NW, Suite 4B-1, Washington, DC 20010.
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke's Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
Circulation encourages readers to submit cardiovascular images to Dr Hugh A. McAllister, Jr, St Luke's Episcopal Hospital and Texas Heart Institute, 6720 Bertner Ave, MC1-267, Houston, TX 77030.
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