1004-57 Regional Left Ventricular Function by Intraventricular Ultrasound in Patients with Myocardial Infarction

Regional left ventricular (LV) dysfunction induced by ischemia/infarction is accompanied by increased end-systolic stress because the ischemic LV wall is unable to generate enough tension to contribute effectively to systole. To explore the possibility of assessing regional LV dysfunction as changes in LV wall stress we performed intraventricular echocardiography in 10 patients with a 6.2 french/12.5MHZ catheter at the time of cardiac catheterization. Cross-sectional images obtained at the level of the papillary muscles were analyzed by computer aided system to assess left ventricular wall thickness and radius of curvature (RC) in 16 equi-angular segments. End-systolic segmental endocardial radius of curvature divided by LV wall thickness obtained as segment area divided by the average of endo and epicardial arc lengths was utilized as an index of regional LV performance proportional to segmental LV wall stress. Percent wall thickening (WT%) was reduced (20.7±14.5%) in the territory perfused by the stenosed artery determined at catheterization, when compared with WT% obtained from territory perfused by normal coronaries (34.4±15.8%, p<0.05). In addition, systolic wall thickening was inversely related to the ratio of RC to WT at end-systole (r=0.75, %WT=65.5 – 21.4 (RCIWT), p<0.05) reflecting regional systolic dysfunction with increased circumferential end-systolic wall stress in those regions. In conclusion, intraventricular echocardiography correctly detects regional left ventricular dysfunction and its geometric consequences to local LV performance induced by ischemic myocardial damage. This technique may play an important role in monitoring myocardial injury by ischemia during invasive interventional procedures