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Biomedical subjects

A J Buda

Publications and source records attributed to A J Buda.

At least 91 records · Page 5Linked to original sources

Myocardial infarct extension: prevalence, clinical significance, and problems in diagnosis.

To examine the prevalence, clinical significance, and problems in the diagnosis of myocardial infarct (MI) extension, 103 patients with acute MI were studied. Each patient underwent enzymatic infarct sizing in the initial 72 hours and then had quantitative CK-MB (myocardial isoenzyme of serum creatine kinase) analysis at 8-hour intervals over the remaining hospitalization. In addition, daily standard 12-lead ECGs and documentation of prolonged (greater than 15 minutes) resting ischemic chest pain were recorded. MI extension, by CK-MB methods, occurred in 32 (31%) of 103 patients at 5.9 +/- 0.3 days after initial infarction. ECG changes suggesting MI extension occurred in 14 (14%), but only six of these patients had extension by CK-MB. Similarly, recurrent chest pain following initial MI occurred in 28 (27%), but enzymatic extension was evident in only 11 of these patients. MI extension resulted in significantly greater early in-hospital mortality (16%) compared to those patients without MI extension (2.8%, p less than 0.05). Thus MI extension occurs commonly and may explain some early in-hospital deaths post MI. The usual clinical and ECG diagnostic parameters utilized are insensitive indicators of enzymatic MI extension.

Adult↗

Automatic computer processing of digital 2-dimensional echocardiograms.

Quantitative studies of left ventricular function using 2-dimensional echocardiography have been limited because of a lack of computerized methods to automatically analyze the echocardiographic images. Previous computer efforts have been directed at digitizing the video output of the 2-D echocardiogram, but this digitizing method has significant limitations. A direct digitization method that produces improvement in signal-to-noise ratio and, subsequently, improved automatic detection of endocardial and epicardial borders, was developed. With definition of these edges, left ventricular global and regional analysis is possible frame by frame so that dynamic changes in cardiac function may be assessed throughout the cardiac cycle. Further technologic advances in 2-D echocardiographic acquisition and image processing should allow computer processing of 2-D echocardiographic data in real time.

Computers↗

Impact of radionuclide techniques on evaluation of patients with ischemic heart disease.

Radiotracer studies of the heart have become clinically important in the last decade, especially for evaluation of patients with known or suspected ischemic heart disease. Radionuclide ventriculography provides quantitative measures of biventricular function and regional wall motion. Recent technical advances include the development of computer programs for analyzing diastolic function, parametric imaging methods such as "phase" analysis and methods for calculating absolute ventricular volumes. Thallium-201 scans provide maps of regional myocardial perfusion. Recent advances include development of computer programs to quantitate regional thallium-201 uptake and to calculate thallium-201 turnover rates and the development of tomographic imaging systems. Technetium-99m pyrophosphate localizes in irreversibly damaged myocardium and provides a method for diagnosing, localizing and sizing acute myocardial infarcts. Recent applications include tomographic imaging to improve image contrast and development of criteria to identify high risk patients after infarction. Two important trends affecting the application of all the radionuclide studies in clinical cardiologic practice are the increasing use of decision analysis for incorporating results of multiple tests into single diagnostic probability statements, and the use of diagnostic algorithms that include the radionuclide studies to optimize the cost effectiveness of evaluation of patients with ischemic heart disease.

Coronary Angiography↗

Spontaneous changes in thallium-201 myocardial perfusion imaging after myocardial infarction.

To examine regional myocardial perfusion after myocardial infarction, 26 patients underwent exercise electrocardiographic testing with thallium-201 myocardial perfusion imaging 3 weeks and 3 months after infarction. At 3 weeks, 9 of 26 patients (35%) had myocardial ischemia by exercise electrocardiographic testing, whereas 18 of 26 (69%) had ischemia by thallium-201 imaging. The thallium-201 scintigrams were scored by dividing each image, in 3 views, into 5 segments, using a 5-point scoring scheme. The exercise thallium-201 score was 44.3 +/- 1.2 and increased to 47.3 +/- 1.2 in the redistribution study (p less than 0.001). Three months after infarction, although there was a significantly greater rate-pressure product which would predict a larger ischemic defect and a decrease in the stress thallium-201 score, the stress score was improved (48.3 +/- 1.1, p less than 0.001). The redistribution score was similar, that is, 48.9 +/- 1.0. The improvement in thallium-201 myocardial perfusion was associated with a loss of stress-induced ischemia in 8 patients (30%). These results indicate that spontaneous improvements in thallium-201 myocardial perfusion imaging may occur after myocardial infarction.

Adult↗

Coronary disease progression and its effect on left ventricular function.

To determine the effect of coronary disease progression on left ventricular function, 47 patients who had two cardiac catheterizations at a mean interval of 25 months (range three to 92 months) without intervening surgery were studied. Of these, 35 patients had coronary disease and 12 patients had normal or near normal coronary arteries. Coronary disease progression was seen more often in patients with initial coronary disease than in those without significant disease (66 percent vs 25 percent, p less than 0.02). Left ventricular ejection fraction decreased in patients with coronary disease progression (0.63 +/- 0.03 to 0.51 +/- 0.04, p less than 0.01) but was unchanged in patients without progressive disease (0.58 +/- 0.04 to 0.57 +/- 0.93, p = NS). Interval myocardial infarction was the major cause of deteriorating left ventricular function. The rate or degree of coronary disease progression did not predictably change global left ventricular function, and progressive disease in individual vessels did not predictably alter regional left ventricular function. The presence or development of collateral vessels did not significantly alter ventricular performance.

Angiography↗

Coronary artery spasm during myocardial infarction.

A 51 year old man presented with unstable angina. Following initial improvement, the patient had prolonged, continuous chest pain resulting in myocardial infarction. During the evolving myocardial infarction, coronary angiography was performed and demonstrated coronary spasm superimposed on a high-grade atherosclerotic lesion. The role of coronary spasm in the etiology of myocardial infarction is discussed. Subsequent aorto-coronary bypass surgery was performed uneventfully.

Coronary Angiography↗

Rapidly progressive vegetative endocarditis.

Echocardiography has become a valuable tool in visualizing and localizing vegetations in patients with bacterial endocarditis. Since the natural course of vegetative lesions remains poorly understood, we report a case of a rapidly progressive vegetative lesion in a patient with staphylococcal endocarditis. Although the significance of this observation will require a larger experience, it may represent an accelerated form of disease necessitating surgical management.

Adult↗

Coronary artery spasm in the denervated transplanted human heart: a clue to underlying mechanisms.

The mechanism of coronary artery spasm has been poorly understood but there has been some suggestion that cardiac autonomic innervation may play an important role. We report coronary artery spasm in a 43 year old man two years after he had received a transplant. Provocative pharmacologic testing suggested functional denervation of the patient's heart. Thus, coronary artery spasm can occur in the transplanted, denervated human heart. Autonomic innervation of the heart is not essential in all cases of coronary spasm, and circulating catecholamines and/or metabolic of hormonal products may play an important role.

Adolescent↗

Abnormalities of pulmonary artery wedge pressures in sleep-induced apnea.

Six patients with sleep apnea syndrome were studied with continuous hemodynamic monitoring during sleep. Sleep apnea had been previously documented with an average number of apneas per hour of sleep ranging from 23 to 93 ((mean 63). There was significant decrease in heart rate during sleep (82 +/- 5 to 69 +/- 6, P less than 0.01). There was a significant rise in systemic blood pressure (103 +/- 2 mn Hg to 116 +/- 6 mm Hg, P less than 0.05) and pulmonary artery pressure (20 +/- 1 mm Hg to 32 +/- 5 mm Hg) during sleep. In addition, pulmonary artery wedge pressure increased (12 +/- 2 mm Hg to 20 +/- 3 mm Hg, P less than 0.05) during sleep and 5 of the 6 patients developed an abnormal pulmonary wedge pressure. There was a significant decrease in PO2 during sleep (71 +/- 3 mm Hg to 49 +/- 2 mm Hg, P less than 0.005). These findings suggest that increases in pulmonary wedge pressures may be contributing to increase in pulmonary artery pressures in these patients during sleep.

Adult↗

Serial angiographic studies before and after acute myocardial infarction in man.

In this study, 6 patients underwent angiographic assessment prior to and subsequent to acute myocardial infarction. The mean inter-angiographic interval was 36 months and the mean infarct to angiography interval was 8 months. Left ventricular ejection fraction decreased from 0.69 to 0.45 after infarction. The degree of left ventricular dysfunction after infarction did not necessarily relate to the site or type of infarction. All patients had significant progression of their coronary lesions with occlusion of a major coronary vessel in the interval. Coronary artery occlusion with infarction produces a variable degree of damage and subsequent left ventricular dysfunction.

Adult↗

Effect of negative intrathoracic pressure on left ventricular outflow tract obstruction in muscular subaortic stenosis.

To study the effect of respiration and negative intrathoracic pressure on the left ventricular outflow tract gradient in patients with muscular subaortic stenosis, we studied nine patients using various respiratory maneuvers at the time of cardiac catheterization. Deep inspiration decreased the left ventricular outflow tract gradient from 60 +/- 11 to 34 +/- 6 mm Hg (p less than 0.01) and decreased the left ventricular ejection time (corrected for heart rate) from 0.42 +/- 0.01 to 0.38 +/- 0.01 second (p less than 0.001). The Müller maneuver decreased the left ventricular outflow tract gradient from 69 +/- 13 to 7 +/- 3 mm Hg (p less than 0.001) and decreased the corrected left ventricular ejection time from 0.42 +/- 0.02 to 0.24 +/- 0.01 second (p less than 0.01). In keeping with this amelioration of left ventricular outflow tract obstruction, echocardiography showed a reduction or abolition of the systolic anterior motion of the anterior mitral leaflet, and auscultatory and phonocardiographic studies revealed a decrease or abolition of the apical systolic murmur. These findings indicate that negative intrathoracic pressure reduced the left ventricular outflow tract gradient in muscular subaortic stenosis. We believe that negative intrathoracic pressure produced these changes by increasing left ventricular afterload through an increase in left ventricular transmural pressure, resulting in a decrease in the left ventricular outflow tract obstruction. These observations provide an explanation for the decrease in pressure gradient that occurs on inspiration in patients with muscular subaortic stenosis.

Adolescent↗

Long-term results following coronary bypass operation. Importance of preoperative actors and complete revascularization.

The initial 102 patients who underwent aorta-coronary bypass grafting between 1969 and 1971 were followed for a mean of 96 months (minimum follow-up 7 years). Preoperative variables predictive of survival at 5 years were stability of angina, previous heart failure, and left ventricular function. Stability of angina, previous heart failure, previous myocardial infarction, and smoking were important predictors of symptomatic status at 5 years. At operation, 62 patients had anatomic or technically complete revascularization, whereas 40 had incomplete revascularization. There was a significantly improved survival rate in those patients who were completely revascularized. The 5 year survival rate was 84% for completely revascularized patients compared to 96% for incompletely revascularized patient (p less than 0.02). This improvement in survival was continued to 9 years. There was also a significant improvement in asymptomatic status of the completely revascularized patients compared to the incompletely revascularized patients. At 2 years, 75% of the completely revascularized subjects were asymptomatic compared to 45% of the incompletely revascularized patients. However, this difference disappeared after 5 years. Thus complete myocardial revascularization is superior to incomplete revascularization in terms of survival and asymptomatic state. Preoperative variables may be useful in predicting postoperative results.

Actuarial Analysis↗

Coronary artery spasm during acute myocardial infarction.

A 51 year old man presented with unstable angina. Following initial improvement, the patient had prolonged, continuous chest pain resulting in myocardial infarction. During the evolving myocardial infarction, coronary angiography was performed and demonstrated coronary spasm superimposed on a high-grade atherosclerotic lesion. The role of coronary spasm in the etiology of myocardial infarction is discussed. Subsequent aorto-coronary bypass surgery was performed uneventfully.

Acute Disease↗

Is it important to preserve the chordae tendinae and papillary muscles during mitral valve replacement?

To evaluate the importance of preserving chordae tendinae and papillary muscles to left ventricular function after mitral valve replacement, 12 dogs had Carpentier-Edwards or Björk-Shiley mitral valves inserted. Cardiopulmonary bypass, systemic hypothermia at 25 degrees C and cold cardioplegia were used. The period of anoxic arrest was 30 minutes. In six dogs, mitral valve replacement was performed after complete excision of the mitral valve. In the other six dogs the anterior leaflet was partially excised but all chordae tendinae and papillary muscles were left intact. Hemodynamic measurements, including left ventricular function following volume loading, were made preoperatively and postoperatively. Left ventricular angiograms were obtained postoperatively in all dogs. Preoperatively there was no significant difference in the left ventricular function curves in the two groups, but postoperatively the curves showed significant differences. In the group with preserved chordae tendinae, left ventricular function improved with volume loading to a left ventricular end-diastolic pressure of 20 mm Hg while in the group with divided chordae tendinae, function improved more slowly and ceased to improve after loading to an end-diastolic pressure of 15 mm Hg. The mean left ventricular ejection fraction following mitral valve replacement with preserved papillary muscles was 0.62 +/- 0.01 and with divided papillary muscles was 0.45 +/- 0.05 (P less than 0.05). The authors conclude that it is important to preserve chordae tendinae and papillary muscles when carrying out mitral valve replacement.

Animals↗

The effect of hemodialysis on cardiac rhythm and performance.

The effects of hemodialysis on cardiac rhythm and left ventricular function were evaluated by Holter electrocardiographic monitoring and M-mode echocardiography in 22 stable patients on regular hemodialysis in hospital. Significant ventricular arrhythmias occurred in 9%. Mean left ventricular volume in diastole (LVVd) decreased significantly after dialysis from 156 +/- 12 ml to 135 +/- 9 ml (P less than 0.001). Similarly, mean left ventricular volume in systole (LVVs) decreased from 51 +/- 9 ml to 42 +/- 6 ml (P less than 0.025). Left ventricular function, as measured by mean velocity of circumferential fiber shortening (VCF), increased significantly for the entire group from 1.25 +/- 0.06 circ/sec to 1.38 +/- 0.06 circ/sec (P less than 0.05). Pre-dialysis VCF was normal in 15 patients (Group 1) and abnormal (less than 1.10 circ/sec) in 7 patients (Group 2). The mean VCF after VCF after dialysis did not change in Group 1 (1.40 +/- 0.05 circ/sec to 1.42 +/- 0.06 circ/sec, P = NS) but increased significantly in Group 2 (0.92 +/- 0.06 circ/sec to 1.29 +/- 0.12 circ/sec, P less than 0.005). There was no significant change in cardiac output or peripheral vascular resistance. Hemodialysis, when performed with careful potassium monitoring, has a low incidence of ventricular arrhythmias. In addition, hemodialysis reduces left ventricular volumes and improves overall cardiac performance in patients with abnormal left ventricular function predialysis.

Adult↗

Detection of entrapped intracardiac air with intraoperative echocardiography.

Embolization of entrapped intracardiac air represents a significant risk to the patient undergoing open heart surgery. To date, there have been no menas available to ensure that the heart is free of air prior to restoration of the circulation. To assess whether M mode echocardiography can accurately detect intracardiac air, we studied 10 dogs during cardiopulmonary bypass. Randomly, air was or was not injected into the left ventricular cavity of the fibrillating heart. Intracardiac air could be recognized by the presence of a stippled granular pattern, or a loss of the discrete linear echoes or decreased far field echoes, or any combination of these three. In all, 131 random observations were made. When 1.0 cc of air was injected, sensitivity and specificity were both 100 percent, but when 0.2 cc was injected, sensitivity and specificity decreased to 86 and 58 percent, respectively. thus, M mode echocardiography appears to provide a sensitive and specific tool for detecting intracardiac air.

Animals↗