Angiographically assessed coronary arterial patency and reocclusion in patients with acute myocardial infarction treated with anistreplase: results of the anistreplase reocclusion multicenter study (ARMS).

In this open multicenter study, 156 patients with acute myocardial infarction received 30 U of anistreplase intravenously over 5 minutes within 4 hours of the onset of chest pain. The patency of the infarct-related vessel was determined by coronary angiography 90 minutes after anistreplase treatment, and also 24 hours after treatment, in patients with a patent infarct-related vessel at 90 minutes, to assess the reocclusion rate. The investigators categorized the infarct-related vessel as patent or occluded, and 2 independent cardiologists graded the infarct-related vessel according to the Thrombolysis in Myocardial Infarction (TIMI) perfusion criteria. At the 90-minute assessment, 106 of 145 evaluable patients (73%) had patent infarct-related vessels, and 39 of 145 (27%) had occluded infarct-related vessels. Of the 139 independently assessed patients, 98 (71%) had TIMI grades 2 or 3 and 41 (29%) had TIMI grades 0 or 1. At the 24-hour assessment, 98 of 102 patients (96%) had a patent infarct-related vessel, and reocclusion had occurred in 4 of 102 patients (4%). Of the 94 independently assessed patients 90 (96%) had TIMI grades 2 or 3, and 4 (4%) had TIMI grades 0 or 1. The reliability of noninvasive parameters as indicators of achieved patency of the infarct-related vessel was estimated by means of correlation with patency assessed by coronary angiography. A significant correlation of 0.62 was found. The patency rate of 71 to 73% after use of anistreplase in patients with acute myocardial infarction corresponds with findings in earlier studies. The low reocclusion rate of 4% after use of anistreplase probably reflects the prolonged action of anistreplase.

Radiation damage to pacemakers from radiotherapy.

The literature shows that radiation treatment with a high dose of ionizing radiation is becoming an increasing risk for patients with a pacemaker. In our investigation, 23 pacemakers were subjected to a destructive radiation test. Of these 23, five proved unable to withstand a dose of 70 Gy. One pacemaker failed at a dose of only 13 Gy. Our results are compared with those reported in other recent publications. Analysis of the data shows that the CMOS electronic device, which is currently used in practically all pacemakers, is responsible for the high sensitivity to ionizing radiation. We conclude that direct irradiation of the pacemaker is contraindicated in all cases.

Location and size of acute transmural myocardial infarction estimated from thallium-201 scintiscans. A clinicopathological study.

A clinicopathological study was performed in 23 patients who died from acute transmural myocardial infarction and who had been studied with thallium-201 during the acute phase. Twenty patients died within five days and three later than five days after scintigraphy. The scintigraphic location and the estimated size of infarction in vivo were correlated with postmortem findings. There was good agreement in 91% between scintigraphic and postmortem location of infarction and in 70% between the ECG and postmortem findings. The size of infarction as determined from computer-processed schematic drawings of postmortem slices of the heart correlated well with the size determined from processed schematic drawings of the scintiscans (r = 0.91 for anterior infarction, r = 0.97 for inferior infarction, r = 0.86 for anterior-inferior infarction). It is concluded that thallium-201 scintigraphy provided more precise location of infarction than the ECG and that the size of the scintigraphically abnormal area reflected the extent of necrotic myocardium.