Effect of left ventricular assist device on myocardial ischemic injury--analysis of epicardial mapping electrocardiography and myocardial regional blood flow
Yamamoto, T.
Nihon Kyobu Geka Gakkai 36(11): 2363-2371
1988
ISSN/ISBN: 0369-4739 PMID: 3209891 Document Number: 309146
The effects of left ventricular assist device (LVAD) on the severity of myocardial ischemic injury was studied in swine following acute coronary occlusion. In 14 swine (41.5 .+-. 6.2 kg), the left descending coronary artery was ligated distal to the first diagonal branch. In the experimental group, epicardial mapping electrocardiograms were taken at 20 points on the anterior surface of left ventricle. The number of points on which ST elevation more than 2 mV was observed (NST) and the total sum of ST elevation was used as an index of the severity of ischemic injury. Myocardial blood flow (MBF) was measured simultanously using electrolytically generated hydrogen gas at intact, marginal and infarcted area which were determined by ST change on e-ECG. LVAD was started 30 minutes after ligation and derived from 120 minutes. No significant change on MBF was observed in intact and infarcted myocardium after LVAD driving compared with control value. MBF in marginal area was increased significantly (p < 0.01) from 67.5 .+-. 17.4 ml/min/100 g to 104.4 .+-. 20.6 ml/min/100 g 30 minutes after LVAD driving. This kind of tendency continued for 120 minutes till LVAD was stopped. NST decreased from 15.6 .+-. 2.9 points to 10.5 .+-. 2.4 points during 120 minutes' driving of LVAD. Significant changes (p < 0.01) on Sigma-ST was also observed between LVAD group and control group at each 30 minutes from 30 to 120 minutes after LVAD start. Significant relationship (Y = 0.75X + 21.49, r = 0.88, p < 0.01) between endocardial viability ratio and MBF on marginal area was shown. These experimented results were indicating that LVAD reduced the severity of myocardial ischemia injury by increasing MBF in marginal so called jeopardized myocardium.