Ga. Hurwitz et al., MARKERS OF LEFT-VENTRICULAR DYSFUNCTION INDUCED BY EXERCISE, DIPYRIDAMOLE OR COMBINED STRESS ON ECG-GATED MYOCARDIAL PERFUSION SCANS, Nuclear medicine communications, 14(4), 1993, pp. 318-327
An index of left ventricular contraction can be extracted from the cav
itary time-activity curve of electrocardiographic (ECG)-gated myocardi
al perfusion scans. To assess the induction of stress-induced myocardi
al depression, we compared contraction indexes derived from immediate
poststress and delayed Tl-201 images with indexes of ventricular dilat
ion and lung uptake in the prediction of severe coronary artery diseas
e (defined as two or more 90% stenoses). Stress procedures were perfor
med in 93 patients with symptom-limited supine bicycle exercise alone,
and in 227 with intravenous dipyridamole, combined where possible wit
h exercise. The immediate and delayed contraction indexes reflected le
ft ventricular dysfunction on ventriculography (P<0.0001), but additio
nally the immediate index was reduced (P<0.0001) in severe coronary di
sease. Stress-induced hypokinesis was seen frequently after each of th
e tes t modes. The relationship with angiographic findings was better
defined for indexes of contraction than for lung uptake or ventricular
dilation (P<0.01). The prediction of severe coronary disease was opti
mized by combining the poststress contraction index and lung uptake. T
hese data support the use of ECG-gated myocardial scans in evaluating
the functional consequences of stress/imaging procedures.