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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The electroencephalogram (EEG) was prospectively analyzed in 118 consecutive open-heart procedures. In 96 patients (81%) the records were normal whereas in 22 patients (19%) the EEG showed slow wave activity and decreased electrical voltage. In 16 of these patients the EEG abnormality was transient or only of mild degree. In 10 of this group of patients the abnormality occurred with the institution of total cardiopulmonary bypass (CPB) and returned to normal within 2 minutes. In four other patients the abnormalities were mild, persisted to the end of the CPB, and then returned to normal; in two patients the EEG abnormalities developed in the last half of CPB and then returned to normal. In the remaining six patients the EEG was grossly abnormal. In one of these patients the abnormality was secondary to a previous stroke. In five patients, however, the EEG alerted the surgeon to an otherwise unsuspected poor cerebral blood flow. A serious neurologic insult was probably prevented by identifying and correcting the mechanical cause.
J Thorac Cardiovasc Surg 1978 Jul
PMID:Monitoring of electroencephalogram during open-heart surgery. A prospective analysis of 118 cases. 66 74

To evaluate the importance of time, temperature, and cardioplegia on the ability of the canine myocardium to maintain functional and ultrastructural integrity following induced arrest, we studied 220 dogs by varying myocardial temperature (34 degrees, 24 degrees, and 11 degrees C.), arrest time (0 to 120 minutes), and cardioplegic agents. Change in left ventricular function (LVF) was defined as the arithmetic difference in the center of mass between prearrest and postarrest LVF curves and was expressed as percent recovery of left ventricular stroke work. Left ventricular biopsies were obtained for semiquantitative electron microscopic analysis. After 90 minutes of cross-clamping, only hearts protected with combined hypothermia (H) and potassium-induced cardioplegia (K) significantly recovered prearrest function (24 degrees C.--80 percent, 11 degrees C.--99 percent). Hypothermia (H) alone for 90 minutes was less protective (24 degrees C.--49 percent, 11 degrees C.--59 percent). H preserved 84 percent of function after 60 minutes and 91 percent after 45 minutes. Normothermic arrest resulted in only 39 percent return of function at 45 minutes but could be extended with potassium-induced cardioplegia(K) to 78 percent at 60 minutes and 54 percent at 90 minutes. The addition of procaine plus HK improved protection over HK alone (95 percent versus 80 percent) but by itself was not effective. Neither hydrocortisone nor pretreatment with glucose-insulin-potassium, branched chain amino acids, or propranolol increased the protective effect of HK plus procaine. Inadequately protected groups (normothermia or H without K) showed more myocytic and capillary endothelial damage than the HK groups. No technique of myocardial protection studied completely preserved LVF, but the combination of HK plus procaine resulted in maximal recovery of LVF following cross-clamping for up to 120 minutes.
J Thorac Cardiovasc Surg 1978 Nov
PMID:Effect of cross-clamp time, temperature, and cardioplegic agents on myocardial function after induced arrest. 70 64

Blunt esophagectomy without thoracotomy has been performed in 26 patients: four with benign disease and 22 with carcinomas involving various levels of the esophagus (10 cervicothoracic, one upper third, five middle third, and six distal third). Continuity of the alimentary tract was restored by anastomosing the pharynx or cervical esophagus either to stomach (19 patients) or to a colonic graft (seven patients). Esophageal resection and reconstruction were performed in a single stage in 25 patients, and the esophageal substitute was positioned in the posterior mediastinum in the original esophageal bed in 24 patients. There were no deaths directly related to the technique of blunt esophagectomy. Average intraoperative blood loss was 1,350 ml. for the entire group, 1,650 ml. for those requiring concomitant laryngectomy and 1,050 ml. for those undergoing esophagectomy without laryngectomy. Complications in these patients included pneumothorax (eight), transient hoarseness (five), pleural effusion (five), anastomotic leak (four), subphrenic abscess (one), and cerebrovascular accident (one). The five deaths were due to pheumonia (two), innominate artery rupture (two), and pulmonary embolus (one). Blunt esophagectomy without thoracotomy is safe and is far better tolerated physiologically than the combined transthoracic and abdominal operations more traditionally used for exophageal resection and reconstruction.
J Thorac Cardiovasc Surg 1978 Nov
PMID:Esophagectomy without thoracotomy. 70 69

The myocardial function and the central and peripheral circulation were studied after aortic valve replacement. All patients showed a similar postoperative pattern of response. During the operation, after termination of bypass, the mean arterial blood pressure (Pa,m) was low. The total peripheral vascular resistance (TPR) and pulmonary vascular resistance (PVR) were normal. Immediately after the operation Pa,m, TPR and PVR were higher than peroperatively. The cardiac index (CI) and stroke index (SI) were low, and the heart rate (HR) was high. At this stage the oesophageal temperature was increasing, but there was no shivering. Then followed a period in which Pa,m and TPR decreased, while CI and SI remained essentially unchanged. The oesophageal temperature reached its highest value 5 hours postoperatively. Peripheral warming began in the 3rd hour postoperatively and was completed in the 6th hour, when the peripheral temperature was 35 degrees C. The progressive peripheral warming, with peripheral cutaneous vasodilatation and slight reduction of the heart rate, took place without signs of increasing CI or SI. The left and right ventricular function, expressed as the relation between LVSWI and Pla,m, and RVSWI and Pra,m, respectively, varied postoperatively and showed no signs of improvement at the time of peripheral warming. Cardiac output and myocardial function seemed to be little affected by the obvious changes appearing during the systemic and peripheral vasodilatation in connection with central and peripheral warming.
Scand J Thorac Cardiovasc Surg 1978
PMID:Circulatory adaptation after aortic valve replacement. A clinical study peroperatively and in the early postoperative period. 72 61

The validity of angiocardiographic measurements in assessing the severity of pulmonic valve stenosis was determined. The pulmonic valve orifice area was measured in the lateral projection on cineangiocardiographic films in 24 patients with valvar pulmonic stenosis. The valve orifice area was also obtained in the same patients by the Gorlin and Bache formulae. The right ventricular output value required for insertion in these formulae was obtained by angiocardiographic right ventricular volume measurement and by the Fick method. The correlation between the directly measured valve orifice area and the area calculated using the Fick principle and the Bache formula was 0.80. The substitution of angiocardiographically measured right ventricular stroke volume for the Fick value gave a correlation of 0.82. The results support validity of employing direct angiocardiographic measurements of pulmonic valve orifice area and angiocardiographic right ventricular volume measurements for quantitative assessment of the severity of pulmonic valve stenosis. The angiocardiographic methods thus represent an alternative to the Fick technique which can be used in conditions where the Fick method cannot be expected to give valid results.
Cardiovasc Radiol 1978 Apr 25
PMID:The measurement of pulmonic valve area by angiocardiographic and hemodynamic methods. 74 6

Regional systolic left ventricular performance after myocardial infarct was assessed from 216 radionuclide angiograms performed in 170 patients. Recording of first transit of an intravenously injected bolus of technetium-99m pertechnetate was made by a multicrystal scintillation camera at a framing rate of 20 per second. The RAO view was used and a simultaneous ECG was employed. Statistics adequate for resolving regional events were obtained by a compact bolus input and phasic summation into one representative cycle of data obtained during left ventricular passage. Emphasis was given to imaging of regional systolic left ventricular function: perimeter images of end-systole and end-diastole, regional stroke volume images and ejection fraction images were processed. New trend images were presented that reflect total systolic contraction and improve image quality: regional rate of decrease and increase images, wall motion trend images and regional mean transit time images. In 96% of the cases, correspondence was found between the electrocardiographic location of the infarct and the region of major wall motion and ejection disorder. Akinesia and/or dyskinesia were seen in 77% of the cases; a ventricular aneurysm was found in 11%. Additional areas of wall motion anomalies were shown by 70%. Image analysis, nuclear image signs and their diagnostic meaning, as well as the indications for this nontraumatic examination in coronary heart disease are discussed. Relevant information for medical or surgical therapy can be obtained from early and follow-up studies in patients with unstable, progressive angina, ischemic electrocardiographic signs and those who have had myocardial infarctions.
Cardiovasc Radiol
PMID:Radionuclide angiography of the heart in coronary heart disease: where do we stand? 74 2

Technique and errors of quantitative single plane ventriculography (SPV), and the methods of Dodge and Sandler (Dodge et al, 1962; Sandler and Dodge, 1968) and Greene et al (1967) for determining left ventricular (LV) volume by SPV were evaluated in the intact dog. Stroke volume (SV) and cardiac output (Q) by ventriculography were compared with those obtained by the Fick and dye dilution methods, and their combination. The end-diastolic (EDV) and end-systolic volume (ESV) corrected by appropriate regression equations, the SV (SV=EDV - ESV), and the ejection fraction (EF) were: Dodge and Sandler, 2.26 1.35, 0.91 ml/kg, and 0.42; Greene et al, 2.41, 1.50, 0.91 ml/kg, and 0.39. Using adequate methods, accurate correction for x-ray image magnification, and the appropriate regression equations the standard error of LV volume calculation by single plane radiography, due to unavoidable technical inaccuracies, should not exceed 10% for a single measurement and 5% for the average of two or more successive cardiac cycles. The systematic overestimation of LV volume inherent in ventriculography, and caused by the addition of contrast medium, should not exceed 5% of the true value.
Cardiovasc Res 1976 May
PMID:Evaluation of single plane angiography for left ventricular volume in the intact dog. 78 6

A technique for the beat-by-beat measurement of stroke volume is described. Aortic blood velocity signals are obtained from a catheter-mounted electromagnetic velocity transducer and analysed by a purpose-built analog computer. The stroke volume is computed by integration of each period of systolic forward flow using the velocity signal as its sole input. Automatic compensation of flowmeter drift is incorporated and inappropriate triggering of integration by diastolic artefact is prevented by applying both amplitude and duration criteria for the recognition of systolic forward flow. Early diastolic reverse flow is excluded from integration. The cardiac output, mean aortic flow per beat, and interbeat interval are also computed from the velocity signal. With aortic pressure as an additional input signal the mean arterial pressure per beat and systemic vascular resistance can be computed. The computer outputs are calibrated by a manual method. Preliminary studies comparing values for the cardiac output measured by this system and the direct Fick technique have indicated an excellent correlation between the two methods.
Cardiovasc Res 1976 May
PMID:Analog computer assisted beat-by-beat measurement of stroke volume and related variables in man. 78 7

(1)Every type of exercise is in a sense a unique situation. However, all forms of muscular work do increase the metabolic rate and therefore it is of particular interest to analyse the involvement of the oxygen transport system. The oxygen uptake gives an accurate measure of the aerobic power, and it is highly related to the cardiac output. The VO2 max is under standardized conditions a highly reproducible characteristic of the individual's aerobic fitness. It is however, subject to variations under certain conditions (i.e., after prolonged inactivity, after training, as a consequence of cardiac diseases). The main factor behind such variations in VO2 max is proportional changes in the stroke volume. Therefore a recording of the heart rate during exercise at a given oxygen uptake will reflect these variations in longitudinal studies. Generally speaking, a high heart rate is usually associated with a low stroke volume. However, from this information it is not possible to tell whether this (poor) exercise response was caused by genetic factors, lack of training, impaired heart function, or other factors. (2) Data have been presented suggesting that the maximal transport of oxygen (cardiac output X oxygen content of arterial blood) is limited by the central circulation rather than by the tissues' ability to utilize the oxygen. (3) A multi-stage exercise test on a treadmill or bicycle ergometer will provide a measurement of the rate of work an individual is able to tolerate without symptoms or electro-cardiographic abnormalities...
Prog Cardiovasc Dis
PMID:Quantification of exercise capability and evaluation of physical capacity in man. 78 42

The integrated response to severe exercise involves fourfold to fivefold increases in cardiac output, which are due primarily to increases in cardiac rate and to a lesser extent to augmentation of stroke volume. The increase in stroke volume is partly due to an increase in end-diastolic cardiac size (Frank-Starling mechanism) and secondarily due to a reduction in end-systolic cardiac size. The full role of the Frank-Starling mechanism is masked by the concomitant tachycardia. The reduction in end-systolic dimensions can be related to increased contractility, mediated by beta adrenergic stimulation. Beta adrenergic blockade prevents the inotropic response, the decrease in end-systolic dimensions, and approximately 50% of the tachycardia of exercise. The enhanced cardiac output is distributed preferentially to the exercising muscles including the heart. Blood flow to the heart increases fourfold to fivefold as well, mainly reflecting the augmented metabolic requirements of the myocardium due to near maximal increases in cardiac rate and contractility. Blood flow to the inactive viscera (e.g., kidney and gastrointestinal tract) is maintained during severe exercise in the normal dog. It is suggested that local autoregulatory mechanisms are responsible for maintained visceral flow in the face of neural and hormonal autonomic drive, which acts to constrict renal and mesenteric vessels and to reduce blood flow. However, in the presence of circulatory impairment, where oxygen delivery to the exercising muscles is impaired as occurs to complete heart block where normal heart rate increases during exercise are prevented, or in congestive right heart failure, where normal stroke volume increases during exercise are impaired, or in the presence of severe anemia, where oxygen-carrying capacity of the blood is limited, visceral blood flows are reduced drastically and blood is diverted to the exercising musculature. Thus,, visceral flow is normally maintained during severe exercise as long as all other compensatory mechanisms remain intact. However, when any other compensatory mechanism is disrupted (even the elimination of splenic reserve in the dog), reduction and diversion of visceral flow occur.
Prog Cardiovasc Dis
PMID:Cardiovascular adjustments to exercise: hemodynamics and mechanisms. 79 Apr 60


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