SIGNIFICANCE OF TRANSIENT DILATATION OF THE LEFT-VENTRICLE ON DIPYRIDAMOLE-THALLIUM IMAGING IN SINGLE-VESSEL DISEASE - ASSESSMENT OF THE EFFICACY OF CORONARY ANGIOPLASTY

To evaluate the implication of scintigraphic transient dilatation of t he left ventricle in patients with single-vessel disease, 10 consecuti ve patients with critical stenosis in the left anterior descending cor onary artery underwent percutaneous transluminal coronary angioplasty. They prospectively underwent dipyridamole-thallium imaging before and after the procedure. The initial/delayed delayed ratio of the left ve ntricular dimension, which was quantitatively measured as the distance between the two peaks of a count profile curve on a 45 degrees left a nterior oblique planar image, was defined as the dilatation ratio of t he left ventricle. Angiographically successful coronary angioplasty wa s performed in all patients. The mean luminal narrowing in the dilated segments decreased from 95 +/- 8% (range 75-99) to 20 +/- 20% (range 0-50; p < 0.0001). The reversible perfusion defect, which was seen in all patients before angioplasty, was found in 4 patients after angiopl asty despite successful procedure. The dilatation ratio significantly decreased from 1.17 +/- 0.10 (range 1.07-1.37) to 0.96 +/- 0.05 (range 0.89-1.03) after successful angioplasty (p < 0.0001). Quantitatively assessed transient dilatation of the left ventricle on dipyridamole-th allium imaging is useful in the evaluation of the efficacy of coronary angioplasty. Disappearance of this phenomenon after angioplasty may i ndicate success of the procedure.