Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Regional contraction of ischemic anterior and normal lateral left ventricular myocardium was measured with isometric force gauges after 5, 10, 15, and 20 minutes of anterior descending coronary artery occlusion-each followed by 10 minutes of reperfusion. Multiple myocardial biopsies of both regions were taken at these same intervals and examined by electron microscopic techniques. Mean contraction of the ischemic area fell significantly in 15 to 30 seconds and returned to an average of 68, 51, 40, and 28 per cent, respectively, after 5, 10, 15, and 20 minutes of ischemia. Simultaneously, focal morphologic changes were detected after 5 and 10 minutes, were more clear and widespread at 15 minutes, and diffuse and unequivocal at 20 minutes, when return of local contraction was minimal. The changes of myocardial morphology in the ischemic area as seen by electron microscopy were: reduced content of glycogen granules and mitochondrial changes. The latter began to appear at 5 minutes and consisted of swelling, disruption of cristae, and reduction of matrix. This study indicates a qualitative correlation between ultrastructural changes in regionally ischemic myocardium and diminished regional function in the intact heart. At 5 and 10 minutes the mitochondrial changes were focal, requiring multiple samples, while at 15 and 20 minutes they became more widespread, making the occasional sample more representative.
J Thorac Cardiovasc Surg 1975 Aug
PMID:Myocardial ultrastructure and function during progressive early ischemia in the intact heart. 115 14

The intraventricular resection technique for giant aneurysm of the left ventricle decreases anoxic cardiac arrest time and controls the detachment of intramural thrombus. To perform this technique, it is necessary to expose only a longitudinal segment on the anterior aspect of the aneurysm to permit a ventriculotomy parallel to the anterior descending coronary artery 4-5 cm away. In the same way, to resect a giant aneurysm of the diaphragmatic aspect, only a segment parallel to the posterior descending coronary artery needs to be exposed. Then with the clear intraventricular vision of the limit between the fibrous sac and the contracting left ventricle, the surgeon rapidly detaches the aneurysm. In any case besides the relation of this limit, the transecting line must keep away at least 4 cm from the implantation of the papillary muscle of the mitral valve, in order to leave an adequate functional chamber for the left ventricle. The early visualization of the mitral apparatus during the resection of giant aneurysm is another basic advantage of the intraventricular approach. The ventriculotomy is closed with a running suture and coronary circulation is restored. Anoxic cardiac arrest averaged 15 minutes in the five out of six cases of giant aneurysm treated with this technique. In the period July 1972-December 1973, 28 aneurysms of the left ventricle with varied associated pathology have been treated in this surgical unit, with 14% (4 cases) mortality. By contrast, no death has been registered in this severely ill group of six patients with giant left ventricular aneurysm. In cases I and VI myocardial revascularization was added. Two important aspects contribute to the excellent long term result in this group. 1. Correction of the altered geometry and consequent dysfunction of the left ventricle. 2. Correction of the functional ischemia of the contracting myocardium. The presence of giant aneurysm increases the left ventricle wall tension, including the contracting mass, and consequently the myocardial oxygen consumption.
J Cardiovasc Surg (Torino)
PMID:Surgical treatment of giant left ventricular aneurysms. The intraventricular resection technique. 118 75

The risk of open heart surgery can be lowered by combination of different methods of myocardial protection. 1. Cardioplegia with a potassium free Mg-1-aspartate and Procaine-solution (Cardioplegin). 2. Coronary perfusion after ischemia longer than 35-40 minutes in case of excessive left ventricular hypertrophy or failure. 3. Hypothermia. Surface cooling gives an additional safety if coronary perfusion is not ideal possible in case of multiple coronary stenoses. For patients with this dispositions a continuous coronary perfusion with cardioplegic solution might be advisable, as it was presented by Gercken in his paper. This method was used three times already in human, but is still in an experimental stage.
J Cardiovasc Surg (Torino)
PMID:Induced ischemic cardiac arrest. Clinical and experimental results with magnesium-aspartate-procaine solution (Cardioplegin). 119 31

In 17 patients who underwent openheart surgery with cardiopulmonary bypass using heparinized fresh blood for priming the heart-lung machine the following investigations were done: Blood samples taken at different periods of surgery were assayed for total calcium (Catot), ionized calcium (Ca++), magnesium (Mg), hemoglobin, total pasma proteins, and the acid-base-status. Considering the different kinds of cardiopulmonary bypass the patients were divided into three groups: In the first group the results ofsurgical procedure with and without hemodilution perfusion were compared. During hemodilution perfusion Catot decreased markedly whereas Ca++ remained nearly constant. In the second group the influence of different calcium concentrations of the prime solution on Catot and Ca was tested. A low calcium content of 2.8 mEq/1 lowered Catot and Ca++ to subnormal levels. In the third group results of Mg-induced cardioplegia were compared with findings during surgical procedure with anoxic cardiac arrest. A remarkable increase of magnesium at the perfusion onset could be observed. Magnesium remained within the upper level of normal range until surgery end and decreased to normal values in the postoperative stage. Since energy requirements of the arrested heart and thus the velocity of ATP-breakdown during ischemia are closely related to the Ca++ concentration of the extracellular space low plasma calcium levels are considered to be advantageous during cardiopulmonary bypass. Only at the end of partial bypass before the heart fully takes over circulating work a sufficient calcium substitution is recommended.
J Cardiovasc Surg (Torino)
PMID:Divalent ions and myocardial function during cardiopulmonary by-pass (CPB). Changes of total calcium, ionized calcium, and magnesium in plasma. 119 32

During a 3 year period, direct myocardial revascularization was performed on an urgent basis in 48 patients with intermittent resting chest pain which persisted more than 24 hours despite in-hospital medical therapy and was accompanied by electrocardiographic changes representative of ischemia. Sixteen patients had saphenous vein (SV) grafts exclusively, and 32 patients each had one or two internal mammary artery (IMA) grafts with or without additional vein grafts. Follow-up ranges from 5 to 41 months (mean, 22 months). Twelve patients had single grafts to the left anterior descending coronary artery (LAD), 18 had double grafts, 16 had triple grafts, and 2 had quadruple grafts. The LAD required grafting in every patient. There was one operative death (2 per cent) and one late death from noncardiac causes. There were two (4 per cent) early postoperative myocardial infarcts and no late infarcts. Actuarial analysis projects a survival rate of 96 per cent 3 years postoperatively. Eighty-one per cent of the survivors are in Functional Class I, 17 per cent are in Class II, and 2 per cent are in Class III. All patients had postoperative angiography 2 weeks after operation. Eighty-six per cent of the SV grafts and all IMA grafts were open. No significant differences were observed between mean preoperative and postoperative left ventricular end-diastolic pressures or ejection fractions, but these parameters were noted to improve after operation in several patients. The remarkably high early and late survival rates, the low incidence of myocardial infarction, and the excellent functional results after rather long follow-up indicate that emergency coronary revascularization provides an effective therapy for unstable angina. The use of IMA grafts, when feasible, is a safe and possibly preferable approach in these patients.
J Thorac Cardiovasc Surg 1976 Mar
PMID:Surgical treatment of unstable angina by saphenous vein and internal mammary artery bypass grafting. 124 66

The effects of metabolic accumulation on myocardial metabolism during global heart oxygen deprivation were evaluated in a working in situ swine heart preparation with controlled total coronary blood flow. Myocardial oxygen consumption was depressed to a similar extent by either reducing total coronary flow 60 per cent (ischemia, low coronary perfusion) in 10 swine or by decreasing coronary perfusate PO2 to 30 mm. Hg at normal flows (hypoxemia, high coronary perfusion) in 13 swine. Compared with findings in 13 control hearts, ischemia significantly (p less than 0.05) decreased myocardial oxygen consumption (640 to 390 mumole per hour per gram), glucose uptake (185 to 16 mumole per hour per gram), and free fatty acid consumption (32 to 17 mumole per hour per gram). ttissue levels of glycogen, creatine phosphate, and adenosine triphosphate (tatp) were significantly reduced (p less than 0.005), and tissue lactate, adenosine diphosphate (ADP), and adenosine monophosphate (AMP) were increased (p less than 0.001). During hypoxemia, glucose uptake was increased (240 mumole per hour per gram) and free fatty acid consumption was somewhat less depressed (19 mumole per hour per gram). Creatine phosphate and ATP were higher than with ischemia (p less than 0.01), and lactate, ADP, and AMP accumulations were less (p less than 0.01). Thus, in the period immediately following myocardial oxygen deprivation, inadequate coronary perfusion caused greater metabolic buildup which inhibited myocardial substrate utilization and energy production. High coronary perfusion, even though the perfusate was unoxygenated, was associated with greater preservation of substrate utilization, higher levels of high-energy phosphates, less accumulation of metabolic products, and a longer survival. These data suggest a critical role of coronary perfusion in protecting myocardial metabolism in the immediate period following global heart hypoxia.
J Thorac Cardiovasc Surg 1976 May
PMID:Effects of coronary perfusion during myocardial hypoxia. Comparison of metabolic and hemodynamic events with global ischemia and hypoxemia. 126 57

A series of 65 geriatric patients, operated upon for 76 peripheral arterial embolic events, is presented. The underlying condition was rheumatic heart disease in 8 and arteriosclerotic in 57. No patient was denied surgery unless widespread irreversible ischemia of the limb was present. Limb salvage was accomplished in 35 patients (54%). It was influenced by age, the underlying disease and time elapsed until resumption of circulation to the limb. The mortality rate experienced in this series was very high. 31 patients (48%) died postoperatively, mainly from cardiorespiratory failure. Death was related to the severity of the patients condition before surgery. 29 out of the 34 surviving patients were discharged with a viable limb. The high death rate observed is discussed.
J Cardiovasc Surg (Torino)
PMID:Peripheral arterial embolectomy in the aged. 127 May 3

One hundred consecutive aortic valve replacements were studied. Fifteen patients had a myocardial infarction as a result of the operation, and four of the five deaths in the series stemmed from this group. In the four deaths from infarction, autopsy revealed occlusion of a main coronary artery. This was attributable to coronary perfusion in three instances. All of the 11 survivors who sustained an infarct were free of angina and left ventricular failure 6 weeks after the operation. Patients with infarcts had longer bypass times and larger aortic systolic gradients than the patients who did not have an infarct. It is suggested that an infarct can occur as the result of occlusion of a main coronary artery; this is a fatal event commonly related to trauma from the coronary perfusion cannula. Alternatively, infarction may result from regional ischemia, perhaps without vessel occlusion, and is associated with long bypass times and with large aortic valve gradients. In such cases the prognosis is good. However, myocardial infarction was the major cause of death in this series.
J Thorac Cardiovasc Surg 1976 Jun
PMID:Myocardial infarction complicating aortic valve replacement. 127 36

The Na+/Ca2+ overload inhibitor R 56865 (N-[1-[4-(4-fluorophenoxy)-butyl]-4-piperidinyl)-N-methyl-2- benzothiazolamine) has been reported to prevent or attenuate ischemia- as well as ouabain-induced cellular sodium and calcium load. We investigated the potency of this compound in preventing mechanical, biochemical, and ultrastructural consequences of ouabain (OUA) intoxication in isolated rabbit heart. The protective effect of the digitalis antidote phenytoin (PHT) on the consequences of ouabain intoxication was examined for comparison. In isolated perfused rabbit heart, OUA (0.4 microM) caused an increase in left ventricular end-diastolic pressure (LVEDP) that was accompanied by depletion of high-energy phosphates (80% less than in control), accumulation of tissue lactate (12-fold) and damage of contractile elements and mitochondria. Accumulation of lactate was associated with a decrease in oxygen consumption by the isolated perfused heart. R 56865 (1.0 microM) and phenytoin (60 microM) prevented increase in LVEDP, breakdown of the energy-rich phosphates creatine phosphate (CrP) and ATP, accumulation of lactate, and morphologic changes induced by OUA. The above-mentioned toxic effects of OUA are interpreted as consequences of mitochondrial failure finally leading to breakdown of the oxidative phosphorylation. Thus, we conclude that the protective action of both compounds, R56865 and PHT, may be attributed to prevention or attenuation of mitochondrial failure due to OUA-induced disturbance of ion homeostasis.
J Cardiovasc Pharmacol 1992 Sep
PMID:Effects of R 56865 and phenytoin on mechanical, biochemical, and morphologic changes during ouabain intoxication in isolated perfused rabbit heart. 127 87

Holter monitoring is the most commonly used noninvasive method for assessing antiarrhythmic drug therapy. It can easily be performed and we know the exact criteria for the definition of drug efficacy and the proarrhythmic effect. However, the value of Holter monitoring to predict clinical outcome in patients with malignant ventricular arrhythmias is controversial. Several authors claim that Holter monitoring is useless to evaluate antiarrhythmic drug effects. Theoretical considerations will explain that it is not the technique by itself that is useless; it is the way it is applied. Merely by changing the efficacy criteria, the value of Holter monitoring to assess antiarrhythmic effects can be improved significantly. Nevertheless, Holter monitoring is far from being the ideal method. It focuses only on arrhythmia density, denying that other risk factors such as heart rate variability, ischemia, and QT changes may be of additional prognostic value. Further studies with Holter monitoring should concentrate on the role of these parameters.
J Cardiovasc Pharmacol 1992
PMID:How to evaluate class III antiarrhythmic drug efficacy clinically: the benefits and shortcomings of the noninvasive approach. 127 6


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>