ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

This study was carried out in order to determine the effects of the inspiration of O2-enriched air on the size of myocardial infarction. In 15 anesthetized dogs, epicardial electrograms were recorded from 10 to 14 sites on the anterior surface of the left ventricle before and after intermittent occlusion of the left anterior descending coronary artery or one of its major branches. In each dog, one occlusion was carried out while the fraction of inspired oxygen (FIO2) was 0.20 and the other while the FIO2was 0.40. With an FIO2of 0.20 the average ST-segment elevation ([See Equation in PDF file]) was 4.0 ± 0.6 mV (sem) and the number of sites exhibiting ST-segment elevations exceeding 2 mV (NST) 15 minutes following occlusion was 6.2 ± 0.7 sites; comparable values following occlusion with an FIO2of 0.40 were 1.8 ± 0.4 mV (P< 0.01) and 2.7 ± 0.7 sites (P< 0.01), reflecting reduction in acute myocardial ischemic injury. An FIO2of 1.0 did not decrease myocardial injury further. In 24 other dogs, occlusion was maintained for 24 hours. In nine dogs in which FIO2was increased from 0.20 to 0.40 30 minutes after occlusion, myocardial creatine phosphokinase activity (CPK) was less depressed in sites having comparable levels of ST-segment elevation at 15 minutes than in dogs that respired an FIO2of 0.20 during the entire 24 hours. All (54) sites with ST-segment elevations > 3 mV in the 0.20 FIO2group showed early signs of myocardial infarction, while only 49% of such specimens showed infarction in the 0.40 FIO2group. Thus, it is concluded that 0.40 FIO2following an experimental coronary artery occusion decreases acute ischemic injury and reduces the eventual development of necrosis, as evaluated by enzymatic and histological techniques.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Comparison of aortocoronary saphenous vein graft status at two weeks and at one year was made in two series of patients. The early postoperative evaluation includes 122 patients of the first 138 operated in our institution (182 grafts) and 83 subjects from a second series of 100 patients operated after modifications of surgical techniques (184 grafts). The one-year follow-up study was obtained in 105 patients of the first series (154 grafts) and in 67 of the second (152 grafts). The patency rate at two weeks was not significantly different between the two groups: 86.3% vs. 91.8%. A marked decrease of stenoses noted early at anastomotic sites was observed: 15% to 5.5% (P< 0.025). The patency rate at one year improved from 67% to 85.5% (P< 0.0005). Grafts having flows at operation of at least 50 ml/min had patency rates of 90% in both series. The patency in grafts with initial flows below 50 ml/min increased from 28% to 73% (P< 0.0005). The incidence of late localized graft stenoses ≧40% decreased from 16.5% to 6% (P< 0.025), and diffuse narrowing ≧40% was found in only 12% of the patent grafts at one year in the second series as compared to 31% in the first (P< 0.001). These improved results do not appear to have been influenced by selection favoring better distal run-off in grafted arteries nor by the introduction of sequential grafts to multiple coronary arteries in the second group. Modified surgical techniques may explain the improved results.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Indices based on early systolic ejection rates are theoretically more sensitive to ventricular performance than indices based on the entire systolic ejection (SE) period (mean ejection phase indices-MEPI): mean systolic ejection rate (MSER), mean normalized systolic ejection rate (MNSER) and mean velocity of circumferential fiber shortening (MVcf). The volume ejected in early systole is an indicator of the early rate of ejection. Accordingly, ventricular volume changes were determined by ventriculographic analysis for each third of SE in ml/sec (SER), as normalized systolic ejection rate (NSER), and as percent of stroke volume (PSV). In ten normal controls all these indices were higher in the first third compared to the other thirds of SE. Seven patients with diffuse ventricular disease had depressed values in the first third of SE. Despite "normal" ventriculograms and normal MEPI, eight patients with left anterior descending coronary artery stenoses (> 60%) also had definitely depressed ejection indices during first third of systole. Detailed wall motion analysis in this group showed anteroapical hypokinesis isolated to the first third of SE. These data show that indices based on early SER are more sensitive than MEPI (MVcf, MNSER) for detecting abnormalities in ventricular performance in coronary artery disease.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

Left ventricular anterior wall metabolism was investigated concurrently with global myocardial metabolism by simultaneous preoperation sampling of anterior interventricular venous (AIV) and coronary sinus (CS) as well as arterial bloods in seven patients with severe obstructive lesions of the major coronary arteries, including left anterior descending. Postoperative study was performed two weeks to six months following successful aortocoronary artery bypass surgery. All grafts including the aorto-left anterior descending artery grafts were patent. Preoperatively in three of the seven patients, anterior wall lactate extraction (R%L) was negative at rest. The average R%L at rest (7 ± 14%) was abnormal and was negative (−49 ± 26%) at a maximum supraventricular pacing rate (MPR) of 137 ± 4.6 beats/min. Postoperatively, not only was resting R%L (39 ± 4.4%) normal but also it remained normal during atrial pacing (32 ± 8.5%) even though the postoperative MPR (164 ± 4.4 beats/min) was much higher than the preoperative MPR. Postoperatively AIV pO2both at rest (21 ± 1.1 mm Hg) and at MPR (22 ± 1.3 mm Hg) and directly determined O2saturations (resting: 34 ± 3.0%; MPR:35 ± 2.1%) tended to be higher than the preoperative values (AIV PO2, resting: 18 ± 1.7; MPR: 19 ± 1.7 mm Hg; AIV O2saturation resting: 30 ± 2.7; MPR: 33 ± 3.3%), although only differences in pO2were statistically significant. In five of the seven patients in whom the pre and postoperative left ventricular angiograms could be compared, systolic wall motion of the left ventricular anterior wall improved markedly postoperatively.Average global myocardial lactate extraction (G%L) preoperatively was normal (19 ± 4.8%) at rest but was negative (−22 ± 12%) at MPR. Postoperatively however, G%L both at rest (44 ± 5.5%) and at MPR (34 ± 7.9%) were normal. Coronary sinus pO2and O2saturation were also higher postoperatively compared to the preoperative values. Over-all left ventricular performance indicated by increase in ejection fraction also improved postoperatively.This improvement was not caused by increased coronary blood flow. Postoperative coronary sinus blood flow both at rest (114 ± 19 ml/min) and at MPR (199 ± 27 ml/min) however were less than the preoperative values (resting 136 ± 24, MPR 261 ± 40 ml/min). There was also no increase in global O2delivery and O2consumption despite higher heart rate and rate-pressure product achieved during postoperative pacing stress and the patients did not develop angina. These findings suggest that improved regional and global metabolism and mechanical functions observed postoperatively in these patients may be due to redistribution of blood flow to the ischemic and nonischemic myocardium following successful aortocoronary artery bypass surgery.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

To assess the effects of sodium nitroprusside (5-10 &mgr;g/min) on total and regional cardiac performance, energetics, and lactate metabolism during acute ischemia, studies were performed in 21 open-chest dogs. For studies of regional function and metabolism, length gauges were sutured to the epicardial surface and an epicardial vein adjacent to the artery to be occluded was cannulated.Following occlusion of the left anterior descending coronary artery, cardiac output, mean arterial pressure, epicardial vein blood flow, and systolic shortening of the ischemic segment decreased significantly. In the blood samples from the ischemic zone, but not in those from the coronary sinus, lactate extraction shifted to production. In seven control dogs these alterations persisted throughout the experiment. In 14 animals treated with nitroprusside, cardiac output increased while peripheral resistance and mean arterial pressure decreased. Systolic shortening in the ischemic segment increased from 1.10 ± 0.24 (sem) to 1.77 ± 0.30 mm (P< 0.005). In eight dogs, regional venous outflow increased from 1.9 ± 0.1 to 3.0 ± 0.4 ml/min despite a slight reduction in mean arterial pressure. Concomitantly, regional negative lactate balance was reduced from −61.0 ± 20.0 to −23.2 ± 5.7% (P< 0.05).These results indicate that nitroprusside significantly improves both total cardiac performance and the mechanical performance of regional ischemic myocardium. Moreover, this improvement in mechanical function occurred concomitantly with apparent increase in regional perfusion and reduction in lactate production, suggesting that nitroprusside simultaneously alleviates ischemia.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

The prognostic value of the left ventricular ejection fraction (EF) was compared to that of other commonly used indices — severity of coronary artery disease, left ventricular end-diastolic pressure, cardiac index, and abnormal ECG — in 144 patients with coronary artery disease followed for an average of 14 months on medical management. During this period, 14 patients (10%) died. Analysis of the mortality demonstrated that the EF was the most powerful predictor of short-term survival. Thus, patients with three-vessel coronary artery disease and a normal EF (> 0.50) had a significantly lower mortality (12%) than did patients with three-vessel CAD and a reduced EF (33%,P< 0.001). Similar comparisons were observed within the subgroups with abnormal hemodynamics or an abnormal ECG. Therefore, the EF appears to be an important prognostic guide in the medical therapy of coronary artery disease, and is of significantly more discriminant value than other measurements when combined abnormalities exist.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

In the acute phase of myocardial infarction, short-term prediction of the likelihood of survival helps the physician choose the appropriate therapy for individual patients. Of 122 patients admitted to the coronary care unit of the Thoraxcenter, University Hospital, Rotterdam, with an acute myocardial infarction, 16 died from pump failure. In these and the 106 survivors, the predictive value of peripheral systolic (SP) and diastolic (DP) blood pressure, pulmonary capillary wedge pressure (PCW), mixed venous oxygen saturation (MVO2sat) in the pulmonary artery and heart rate (HR), both alone and in combination, was evaluated at the time of admission and 24 hours later.When, at admission, (DP × MVO2sat)/PCW exceeded 250%, 97/99 patients survived, whereas values below 250% were associated with death in 14/23. All other parameters, taken alone or in other combinations, showed less discriminatory power. The mean value of this index in survivors (549%) was statistically different (P< 0.001) from the mean value in nonsurvivors (183%). Twenty-four hours later all survivors with admission values lower than 250% had an improved index. Of the 14 nonsurvivors with admission values lower than 250%, seven had already died, and in seven others the index had decreased still further. Linear discriminant analysis showed that (0.024 SP − 0.217 PCW + 0.234 MVO2sat) was the most powerful prognostic index at the time of admission; its time course did not provide a more effective prediction of ultimate fatality than (DP × MVO2sat)/PCW.Determination of (DP × MVO2sat)/PCW in patients hospitalized for acute myocardial infarction provides a reliable prognosis for short-term patient survival. Its practical value in guiding patient management, more particularly for initiating mechanical circulatory assistance or for emergency surgery, must be further assessed.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID

摘要:

In order to determine the reproducibility of analyses of left ventriculograms, 35 cineangiograms were evaluated by four observers, two using standard quantitative techniques to determine ventricular volumes and a newly devised quantitative system to evaluate wall motion and two others using only visual inspection of the angiograms.Objective analysis repeated by the same observer correlated well for end-diastolic and end-systolic volumes and ejection fraction (r= .98, .99, .99, respectively) and only one of 105 (1%) wall segments were identified differently. Variability in assessments increased when comparisons were made with a second objective observer. Correlation coefficients for the three volumetric parameters were .93, .98, and .95 and there was disagreement in the assessment of 8% of wall segments. Wide variability was present between an objective and two subjective observers in analyses of end-diastolic volumes (r= .63, .64). Regional wall motion was assessed differently in 19% and 27% of segments, respectively. Though the correlation of objectively and subjectively determined ejection fractions was much better than the correlation for volume (r= .92, .84), it was not as good as the correlation between two objective observers. Occasional errors of clinical significance occurred.We conclude that subjective analysis has a significant error rate and that reproducibility and accuracy of analysis of left ventriculograms require objective analysis.

ISSN:0009-7322    

出版商:OVID    

年代:1975

数据来源: OVID