Evidence for a flow-independent contribution to the phenomenon of thallium redistribution

Although thallium-201 is known to redistribute slowly into regions of ischemic myocardium after restoration of blood flow, it is not clear to what extent normalization of flow is an essential requirement for the redistribution process. In a search for a flow-independent component of thallium redistribution, 12 dogs with stenosis of the circumflex coronary artery underwent atrial pacing for either 20 minutes (group I, 6 dogs) or 2 hours (group II, 6 dogs). Radioactive thallium and radioactive microspheres, 7 to 10 μ, were injected after 10 minutes of atrial pacing in both groups. Pacing resulted in a 40 percent reduction in subendocardial blood flow to the circumflex-perfused myocardium in both groups I and II. This relative reduction in flow was maintained at a stable level over the 2 hour pacing period in group II. Thallium activity in the relatively ischemic zone was significantly greater in dogs with 2 hours of pacing (group II) than in those with 10 minutes of pacing (group I). Redistribution of thallium occurred despite the continued presence of reduced flow in circumflex-perfused endocardial tissue. These data suggest that a significant component of thallium redistribution may be flow-independent.     

Postoperative arrhythmias after coronary artery and cardiac valvular surgery detected by long-term electrocardiographic monitoring.

Twenty-four hour long-term electrocardiographic recordings were used to supplement routine perioperative monitoring to determine the frequency and significance of arrhythmias occurring after coronary artery bypass graft surgery and cardiac valve replacement. Patients underwent “ambulatory” electrocardiographic monitoring for 24 hours before surgery and on the first and fifth days after discharge from intensive care.New arrhythmias occurred in 26 of 50 patients (52 per cent) after coronary artery bypass graft surgery and in six of 15 patients (40 per cent) after valve replacement. This high frequency of arrhythmia detection was directly attributable to the use of long-term electrocardiography. New atrial arrhythmias were common after both valvular and coronary artery bypass graft surgery (44 per cent and 38 per cent of patients, respectively). Ventricular arrhythmias were uncommon preoperatively in both groups but occurred frequently after coronary artery bypass graft surgery (36 per cent). Arrhythmias contributed to morbidity but not to mortality in this series.These results suggest that new atrial arrhythmias occurring after coronary artery bypass graft or valvular surgery may be related more to the immediate intrathoracic sequelae of surgery than to a specific underlying cardiac lesion, in contrast to ventricular arrhythmias which may be more specific for patients with ischemia. Long-term electrocardiographic recording is a useful technique to supplement routine methods of perioperative electrocardiographic monitoring.     

Associations Between Complex PCI and Prasugrel or Clopidogrel Use in Patients With Acute Coronary Syndrome Who Undergo PCI: From the PROMETHEUS Study

Background

Potent P2Y₁₂ inhibitors might offer enhanced benefit against thrombotic events in complex percutaneous coronary intervention (PCI). We examined prasugrel use and outcomes according to PCI complexity, as well as analyzing treatment effects according to thienopyridine type.

Disappearance of abnormal Q waves after aortocoronary bypass surgery

Sixty-one patients were selected from 100 consecutive patients undergoing aortocoronary artery bypass. The number of vessels diseased as defined by coronary arteriography and the number of bypass grafts were recorded. Review of the preoperative electrocardiograms showed an infarct pattern in 26 of the 61 patients and analysis of the postoperative electrocardiograms revealed loss of abnormal Q waves in 3 of the 26. The pre- and postoperative clinical course of these three patients is analyzed and the extent of their coronary artery disease and number of bypass grafts compared with those of the 23 patients who had persistence of the infarction pattern and the 17 patients who manifested new Q waves. Possible explanations for the disappearance of abnormal Q waves are discussed.     

Electrocardiographic responses to atrial pacing and multistage treadmill exercise testing. Correlation with coronary arteriography

Atrial pacing was compared with multistage treadmill exercise testing in 50 patients undergoing diagnostic cardiac catheterization to determine the diagnostic sensitivity of atrial pacing. Coronary artery disease was considered significant if luminal narrowing greater than 75 percent was present. Twenty-one subjects (Group I) had no significant coronary artery disease with vessel narrowing of less than 50 percent. Twelve (Group II) had single vessel disease and 17 (Group III) had disease of two or more vessels.The mean maximal heart rate during atrial pacing was 140/min and during exercise testing was 131/min. A positive atrial pacing test result was obtained in 5 percent of patients in Group I, 17 percent of patients in Group II and 24 percent of patients in Group III. A positive multistage treadmill exercise test result was obtained in 10 percent of patients in Group I, 67 percent of patients in Group II and 94 percent of patients in Group III. These differences are statistically significant (P < 0.001). The sensitivity of atrial pacing was 20 percent compared with 83 percent for multistage treadmill exercise testing. The specificity of atrial pacing was 95 percent compared with 90 percent for multistage treadmill exercise testing. Thus, atrial pacing is an insensitive test in the diagnosis of ischemic heart disease and does not improve the diagnostic value of multistage treadmill exercise testing.     

Spontaneous dehiscence of an aortic commissure complicating idiopathoc aortic root dilatation.

Two patients had spontaneous dehiscence of an aortic commissure producing severe aortic regurgitation. There was dilatation of the aortic root in both cases which could not be attributed to inflammation, syphilis, or a connective tissue disease. Valve ring dilatation probably renders the valve susceptible to rupture by altering the relationship of the cusps to each other thus weakening their mutual support during diastole.     

Comparison of diltiazem at two dose levels with propranolol for treatment of stable angina pectoris

Two dose levels of diltiazem with propranolol were compared in the management of chronic stable angina. Two groups of patients were treated for alternate periods of 4 weeks with each drug in a double-blind crossover with computer-assisted maximal treadmill tests and ambulatory ST-segment monitoring for evaluation of efficacy and safety. In 12 patients who received diltiazem, 180 mg/day, the time to development of angina increased from 5.9 +/- 0.7 minutes (+/- standard error of the mean) during placebo treatment to 8.3 +/- 0.8 minutes during diltiazem treatment and to 9.2 +/- 0.8 minutes with propranolol, 240 mg/day. Three patients became angina-free when they were treated with both drugs. Among 12 patients who received diltiazem, 360 mg/day, 1 patient became angina-free during treatment with both drugs and 1 became angina-free with diltiazem only. The mean exercise time increased from 5.8 +/- 0.7 minutes with placebo to 8.6 +/- 1.0 minutes with diltiazem, 360 mg/day, and to 8.2 +/- 0.6 minutes with propranolol, 240 mg/day. Analysis of variance showed no difference in efficacy between the 2 doses of diltiazem or between the 2 drugs. Ambulatory heart rate was reduced both during the day and at night with both drugs and significantly more with propranolol than with diltiazem treatment. Except for 1 patient in whom a rash developed when given diltiazem, 180 mg/day, and another who had both a rash and first-degree heart block with diltiazem, 360 mg/day, both drugs were well tolerated. Thus, diltiazem in a daily dose of 180 or 360 mg/day is as effective as propranolol for the treatment of chronic stable angina.     

青蒿琥酯分别与诺氟沙星、甲硝唑伍用的体内、外抗恶性疟作用

目的　了解青蒿琥酯分别与诺氟沙星、甲硝唑伍用的体内、外抗疟作用。　方法　采用青蒿琥酯与诺氟沙星 (A组 )或甲硝唑 (B组 )联用 3d疗法治疗无并发症的恶性疟。体外测定采用 Rieckmann体外微量法测定恶性疟原虫对 3种药物单一用药及青蒿琥酯分别与诺氟沙星或甲硝唑联用的敏感性。　结果　体内观察法共收治 70例病人 ,其中 A组 5 5例 ,B组 15例。平均退热时间分别为 (2 6 .5± 16 .5 ) h(8h～ 93h)、(19.2± 11.0 ) h(4h～ 4 1h) ;平均原虫无性体转阴时间分别为 (37.4± 15 .3) h(13h～ 93h)和 (42 .8± 14 .7) h(2 5 h～ 72 h) ;2 8d复燃率分别为 4 7.4 %和 75 .0 %。体外微量法测得青蒿琥酯与诺氟沙星伍用的 ID50 分别为单用组的 5 .9%和 0 .3% ;青蒿琥酯与甲硝唑伍用的 ID50 分别为单用组的38.8%和 5 .6 %。　结论　青蒿琥酯分别与诺氟沙星、甲硝唑伍用在体外对抗青蒿琥酯恶性疟原虫有明显增效作用 ,但在临床治疗中未能提高治愈率     

Dietary control of pathogenesis in C57BLKsJdbdb diabetes mice

Weanling $\text{C57BL}\text{KsJ}$ homozygous diabetic ($\text{db}\text{db}$) and normal littermate (+/+ or +/db) mice were maintained for 5 mon on isocaloric diets containing either 60% sucrose, 23% casein, 8% corn oil (diet C) or 0% sucrose, 83% casein, 8% corn oil (diet B). Diabetic homozygotes consumed more diet C than normals, but ate control amounts of diet B. Diabetic mice fed diet C exhibited 57% mortality between 4 and 5 mo of age. All diabetic mutants fed the carbohydrate-free diet B appeared healthy at 6 mo of age; mutant females were normoglycemic and mutant males were only moderately hyperglycemic. Histological examination of pancreatic islets confirmed the absence of islet degeneration. In diet B maintained mutants, increased carcass fat composition, plasma and pancreatic content of insulin and glucagon, and thymidine incorporation into islets, all established that the db gene was being fully expressed. These results indicate that dietary protein stimulates islet growth and function in $\text{db}\text{db}$ mice, while high levels of refined carbohydrate in the diet predispose islet beta cells to undefined changes that culminate in necrosis. Restricting mutants' intake of a carbohydrte-containing diet to one-half the caloric intake of normal mice failed to block onset of beta cell necrosis. Thus, dietary composition rather than total caloric intake appears to be critical in the induction of islet necrosis and atrophy in this animal model of genetically transmitted diabetes.     

Positional abnormalities of atrioventricular valves in transposition of the great arteries including double outlet right ventricle, atrioventricular valve straddling and malattachment.

Positional abnormalities (straddling or overriding) of the atrioventricular (A-V) valves were studied using angiographic, sector scan echocardiographic and postmortem anatomic data in 10 patients with transposition of the great arteries including double outlet right ventricle. Group I included six patients with tricuspid valve abnormalities. This group was further classified into: (a) patients with anular straddling and abnormal attachment of portions of the tricuspid leaflets in the left ventricle (malattachment) or on the ventricular septum, or both (four patients with d-transposition of the great arteries and hypoplastic right ventricle); and (2) patients with malattachment of portions of the tricuspid valve leaflet to the crest or left ventricular surface of the septum (septal malattachment) without significant anular straddling (two patients with d-transposition of the great arteries).Group II included four patients with mitral valve abnormalities without significant anular straddling, further classified into: (1) patients with septal malattachment of the portions of the mitral valve to the crest and right ventricular surface of the ventricular septum (two patients with double outlet right ventricle); and (2) patients with ventricular malattachment of portions of the mitral valve leaflets to the papillary muscles in the right ventricle (two patients with ventricular septal defect and discordant criss-cross atrioventricular connections).On the basis of these observations and reported experience, two main types of positional abnormalities of the A-V valves were recognized: (1) anular straddling in which the A-V anulus straddled the ventricular septum above the contralateral ventricle, together with ventricular leaflet malattachments, and (2) leaflet malattachment of either the septal or ventricular type without significant straddling of the valve anulus. Angiocardiography and sector scan echocardiography helped to identify these abnormalities of the A-V valves.