Biomedical subjects
Publications and source records attributed to G C Curry.
This well-illustrated article considers the role of plain film examination of the adult patient with valvular heart disease caused by rheumatic heart disease. As stressed in Dr. Elliott's article in this symposium, the importance of interpreting anatomic information within the physiologic framework provided by assessing the pulmonary vasculature cannot be overemphasized.
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Fifty patients with the clinical syndrome of unstable angina pectoris were evaluated. Twenty-seven were randomized into medical or surgical treatment groups and subsequently followed up. The results of the study reveal that: (1) there is approximately a 16 percent incidence rate of significant left main coronary artery disease in patients with this entity at our institution; (2) 10 percent of patients do not have angiographically significant coronary artery disease; (3) pain relief is better in the surgically treated patients, but the 1 1/2 year survival rate is not significantly different between the groups; (4) 50 percent of the medically treated patients again had the syndrome of unstable angina pectoris in the initial few months of the follow-up period; (5) the operative and late postoperative mortality rate in patients presenting with unstable angina pectoris and left main coronary artery disease in this small group of patients was 43 percent; and (6) four of six patients with this syndrome whose condition was deemed inoperable and who were not randomized died within the subsequent few months.
The clinical course and postmortem findings of an unusual case of complete transposition of the great arteries, in which the Mustard operation was not performed until the patient was 12 years of age, are documented with serial catheterizations showing adequate repair. The clinical course of the patient was uneventful for 8 years after surgery, when right (systemic) ventricular failure occurred, resulting in the patient's death at 20 years of age. Late cardiac failure, the cause of death, is not a commonly described problem after successful surgical repair of transposition of the great arteries.
The value of axial cineangiography in several forms of congenital heart disease serves as an illustrated supplement to Section I. These techniques visualize defects in the entire ventricular and atrial septum. In persistent atrioventricular (A-V) canal, it is possible to visualize all parts of both septa, status of the A-V valves (two valves versus a common A-V valve), and if a common A-V valve, its degree of override. In tetralogy of Fallot, the bifurcation of the pulmonary trunk, entire ventricular septum and coronary arteries are vividly shown. The presence of true and confluent pulmonary arteries versus systemic or bronchial arteries in pseudotruncus is clearcut. In double outlet right ventricle or in transpositions with or without double outlet right ventricle, the mitral valve-semilunar valve relationships, the left ventricular outflow tract, subpulmonary region and a straddling tricuspid valve are well demonstrated. In asymmetric septal hypertrophy, biventricular angiography may be circumvented.
Cineangiographic axial techniques were designed to overcome the limitations of conventional angiography in the diagnosis of congenital heart disease. Two basic patient (or equipment) maneuvers are involved; 1) long axis of the heart is aligned perpendicular to the X-ray beam, and 2) rotation of patient results in the heart being radiographically sectioned at 30 degree angles. To accomplish this with fixed vertical and horizontal X-ray tubes, three positions were developed: 1) "hepato-clavicular," "4 chamber," 2) "long axial oblique," 3) "anterior-posterior axial." A fourth, the "sitting-up" projection is discussed. The hepato-clavicular position profiles the posterior ventricular septum and atrial septum, separates the A-V valves, places the four cardiac chambers en face, and clarifies mitral valve-semilunar valve and outflow tract relationships. The long axial oblique profiles the anterior ventricular septum, left ventricular outflow tract, aortic valve-anterior mitral valve leaflet. The sitting-up view visualizes the bifurcation of the pulmonary trunk and separates true pulmonary arteries from systemic collaterals.
The influence of dobutamine on hemodynamics and coronary blood flow was studied in patients after routine cardiac catheterization. The data demonstrated that dobutamine is a powerful inotropic agent at a dose that has a relatively small influence on heart rate. In patients without coronary artery disease dobutamine greatly increased coronary arterial perfusion. In patients with severe coronary artery diseases dobutamine resulted in a much smaller increase in coronary perfusion, and the pattern of perfusion became more inhomogeneous. The results suggest that dobutamine has a potential inotropic value but raise concern about its influence on regional myocardial perfusion in patients with serious coronary artery disease.
The clinical, left ventricular and coronary angiographic data, and the technetium-99m stannous pyrophosphate (99mTc-PYP) myocardial scintigraphic results are presented in 31 patients with unstable angina pectoris. One-third of these patients had positive 99mTc-PYP myocardial scintigrams in a pattern suggesting limited and diffuse subendocardial necrosis. The positive 99mTc-PYP myocardial scintigrams occurred without diagnostic electrocardiographic and cardiac enzyme changes suggestive of myocardial infarction; positive scintigrams seemed to occur more commonly in patients with continuing pain after admission and in those without previous history of myocardial infarction. The positive 99mTc-PYP myocardial scintigrams did not correctly predict coronary anatomical patterns except that positive scintigrams occurred only in patients with coronary artery disease. Neither did the positive scintigrams necessarily occur in that group of patients with the poorest ventricular function though the 2 patients with the lowest ejection fractions both had positive 99mTc-PYP myocardial scintigrams. Finally, when positive 99mTc-PYP scintigrams are the only evidence suggestive of limited subendocardial infarction in patients with unstable angina pectoris, they do not appear to have any prognostic significance in terms of longevity or response to pharmacological or surgical therapy, though the follow-up period so far is short.
The clinical course and coronary arteriographic findings in eight patients with Prinzmetal's variant angina pectoris are reviewed and contrasted to previously reported cases. In six patients with S-T-elevation inferiorly, three had normal coronary arteriograms, one had complete right coronary artery occlusion, one had diffuse triple-vessel disease, and one did not undergo coronary arteriography. In two patients with S-T-elevation anteriorly, severe stenosis of the anterior descending coronary artery was present. Medical treatment in four patients and surgical revascularization of the anterior descending coronary artery in two patients were both accompanied by marked symptomatic improvement. Spontaneous loss of angina occurred in two patients. During 17 months' mean follow-up, seven patients have remained free of angina and one died suddenly. Variant angina pectoris may be accompanied by a variety of coronary arteriographic findings and the prognosis appears more favorable than previously reported.
Of the 27 patients described, 23 were in cardiogenic shock, 2 had severe left ventricular failure, and 2 had medically refractory ventricular tachycardia. Utilizing intraaortic counterpulsation, adequate systemic blood pressure was initially restored in 19 patients. Nine of these were subsequently weaned from circulatory assistance, but only three were discharged from the hospital and are currently alive. The remaining 10 patients who derived initial benefit from circulatory assistance were balloon-dependent in that they could not be weaned from circulatory assistance. Eight of these patients subsequently underwent cardiac catheterization; four had inoperable disease. The remaining four patients underwent surgery for either resection of the area of infarction and/or for myocardial revascularization; only one survived to subsequently leave the hospital. Ventricular volumes were abnormal and ejection fractions were below 30 per cent in all the patients in cardiogenic shock except one who underwent cardiac catheterization and ultimately died. Ejection fractions were greater than 30 per cent in the two patients with cardiogenic shock who were weaned from balloon support and survived to leave the hospital without surgery. Both of these patients had inferior myocardial infarction. The data obtained from this experience suggest that intraaortic counterpulsation is a very useful adjunct to currently existing medical measures to treat both cardiogenic shock and medically refractory left ventricular failure but that most patients have such extensive disease that they can neither be weaned from balloon support nor undergo successful infarctectomy or myocardial revascularization.
The influence of hypertonic mannitol on regional myocardial blood flow and ventricular performance in awake, intact, unsedated dogs with myocardial infarction resulting from chronic occlusion of the proximal left anterior descending coronary artery was studied. tmannitol given to increase serum osmolality 20 mOsm increased regional myocardial blood flow to that portion of the left ventricle supplied by the occluded left anterior descending coronary artery by 22 +/- 2.8% (1.06 +/- 0.19 to 1.36 +/- 0.23 ml/min with g-1) without changing the inner:outer wall flow ratio. Mannitol also significantly increased regional myocardial blood flow to other areas of the left ventricle and the ventricular septum. Mean aortic pressure, maximal LV dP/dt, LV dP/dt/P, and cardiac output also increased significantly after mannitol. Thus hypertonic mannitol increases regional myocardial blood flow and ventricular performance in the awake, unsedated dog with prolonged occlusion of the proximal left anterior descending coronary artery. The increase in regional myocardial blood flow after mannitol under these circumstances probably is at least in part secondary to the increase in blood pressure and contractility. The increases in regional myocardial blood flow after mannitol in this study are less impressive than those that have been previously reported in the setting of either no myocardial ischaemia or acute myocardial ischaemia; this is probably due to the vasodilatation that chronic myocardial ischaemia itself produces in the canine heart.
The influence of a relatively small increase in serum osmolality produced by hypertonic mannitol on ventricular and systemic arterial hemodynamics and coronary blood flow was studied in 20 patients undergoing cardiac catheterization. Mannitol given to increase serum osmolality 10 mOsm resulted in a small but significant increase in mean systemic arterial pressure, maximum LV dp/dt, left ventricular end-diastolic pressure and cardiac output but no significant change in heart rate or hematocrit. The most prominent change in the patients studied, however, was in coronary blood flow which increased 39% after mannitol. Patients with severe two and three vessel coronary artery disease had increased in coronary blood flow similar to those in patients without coronary artery disease. The data suggest the need to further evaluate the physiological importance of the increase in coronary blood flow produced by mannitol in patients with coronary artery disease and indicate the possibility that mannitol might be of value in treating certain problems in patients with coronary artery disease,
The influence of hypertonic mannitol on regional myocardial blood flow and ventricular performance was studied during acute myocardial ischemia in awake, unsedated and in anesthesized dogs and after myocardial infarction in awake unsedated dogs. Regional myocardial blood flow was measured with radioactive microspheres. Generalized increases in regional myocardial blood flow occurred after mannitol in all of the different animal models studied. The increases in coronary blood flow after mannitol were just as impressive in the nonischemic regions as in the ischemic portion of the left ventricle in all of the different models that were examined in this study. Improvement in regional myocardial blood flow to the ischemic area of the left ventricle after mannitol was associated with a reduction in ST segment elevation during acute myocardial ischemia in anesthetized dogs. The increases in regional myocardial flow after mannitol were also associated with increases in contractility, but the increases in flow appeared to be more impressive than the changes in contractility. The data obtained demonstrate that mannitol increases regional coronary blood flow to both ischemic and nonischemic myocardium in both anesthetized and awake, unsedated, intact dogs with acute and chronic myocardial ischemia and that mannitol reduces ST segment elevation during acute myocardial ischemia in anesthetized dogs. Thus the results suggest that under these circumstances the increases in regional myocardial blood flow after mannitol are of physiological importance in reducing the extent of myocardial injury. Since coronary blood flow increased to nonischemic regions the increases in regional myocardial flow demonstrated in this study after mannitol cannot be entirely explained by the mechanism of reduction in ischemic cell swelling.
This paper represents a review of the recent literature on techniques to measure myocardial blood flow in man. A short discussion on flow meters in followed by a more detailed discussion of the radionuclide techniques used to measure myocardial blood flow. The radionuclide techniques are discussed in two groups: (1) qualitative measurement of blood flow using static images; and (2) quantitative measurements of blood flow using diffusible substances that actively enter the cell, radioactive labeled particles, and radioactive diffusible gases.
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Explore the source record for details and available documents.