[Effect of left ventricular assist device (LVAD) after myocardial infarction: study of reinfarction model].
The effect of the left ventricular assist device (LVAD) after myocardial infarction was studied in 10 mongrel dogs. In the first experiment, the left anterior descending coronary artery (LAD) was occluded for one hour, then the LAD was reperfused. Two weeks later, the dogs were divided into two groups. In group I (control, n = 5), the LAD was occluded for 120 minutes, but the LVAD, implanted between left atrium and aorta, was not driven. In group II (pumping, n = 5), the LVAD was started 15 minutes after LAD occlusion, and continued for 115 minutes, then reperfused after 120 minutes of occlusion. The left ventricular segment length was monitored continuously by a pair of titanate-zirconate piezoelectric crystal. End-diastolic length (EDL) and end-systolic length (ESL) were identified. To describe segmental motion, % shortening was defined as follows: %shortening = (EDL-ESL)/EDL x 100. Just after sacrifice, the hearts were removed and sectioned transversely. Area of infarction was measured by planimetry as identified by incubation of heart slices in nitroblue tetrazolium dye. After LAD occlusion, % shortening decreased significantly in both groups. After reperfusion, % shortening increased, but was significantly low in the group I at 30 minutes of reperfusion.(p < 0.05). The EDL of ischemic region increased after coronary occlusion and remained high during LAD occlusion. The EDL was almost the same in both groups at 30 minutes of reperfusion. Area of infarction evaluated weight ratio and transmurality were 10.9 +/- 3.9% versus 11.3 +/- 1.4% and 81.2 +/- 8.9% versus 61.0 +/- 5.1% in comparison of group I versus group II.(ABSTRACT TRUNCATED AT 250 WORDS)
Otaki
K
K
Second Department of Surgery, Hokkaido University School of Medicine, Sapporo, Japan.
D000818:Animals; D004285:Dogs; D006353:Heart-Assist Devices; D009203:Myocardial Infarction / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left / Q000502:physiology*