Coronary angiographic morphology in myocardial infarction: a link between the pathogenesis of unstable angina and myocardial infarction

It has previously been shown that analysis of coronary morphology can separate unstable from stable angina. An eccentric stenosis with a narrow neck or irregular borders, or both, is very common in patients who present with acute unstable angina, whereas it is rare in patients with stable angina. To extend these observations to myocardial infarction, the coronary morphology of 41 patients with acute or recent infarction and nontotally occluded infarct vessels was studied. For all patients, 27 (66%) of 41 infarct vessels contained this eccentric narrowing, whereas only 2 (11%) of 18 noninfarct vessels with narrowing of 50 to less than 100% had this lesion (p less than 0.001). In addition, a separate group of patients with acute myocardial infarction who underwent intracoronary streptokinase infusion were also analyzed in similar fashion. Fourteen (61%) of 23 infarct vessels contained this lesion after streptokinase infusion compared with 1 (9%) of 11 noninfarct vessels with narrowing of 50 to less than 100% (p less than 0.01). Therefore, an eccentric coronary stenosis with a narrow neck or irregular borders, or both, is the most common morphologic feature on angiography in both acute and recent infarction as well as unstable angina. This lesion probably represents either a disrupted atherosclerotic plaque or a partially occlusive or lysed thrombus, or both. The predominance of this morphology in both unstable angina and acute infarction suggests a possible link between these two conditions. Unstable angina and myocardial infarction may form a continuous spectrum with the clinical outcome dependent on the subsequent change in coronary supply relative to myocardial demand.     

Noninvasive in vivo and in vitro study of the St. Jude mitral valve prosthesis: Evaluation using two dimensional and M mode echocardiography,phonocardiography and cinefluoroscopy

Fifteen patients with clinically normal function of a St. Jude mitral valve prosthesis were studied with two dimensional and M mode echocardiography, Cinefluoroscopy and phonocardiography 8 to 292 days after valve replacement. The valve was readily imaged from the left sternal edge and cardiac apex in all patients. On two dimensional echocardiography from the long axis and four chamber views, minimal end-diastolic and endsystolic distances between the interventricular septum and prosthetic valve were 18 ± 5 mm and 13 ± 3 mm, respectively (mean ± standard deviation). On M mode echocardiography both leaflets were imaged throughout the cardiac cycle from the left sternal edge and their motion relative to the valve ring and to one another was easily evaluated. The apical transducer position permits quantitative assessment of individual leaflet motion. Maximal individual diastolic leaflet excursion was 8.7 ± 1 mm and the velocity of leaflet opening and closure was 364 ±103 and 678 ±115 mm/s, respectively.Asynchronous early closure of the posterior leaflet was observed during long cardiac cycles in six of seven patients with atrial fibrillation; the seventh patient had a rapid ventricular response and no long cardiac cycles. Diastolic fluttering of one or both leaflets was also seen during atrial fibrillation after rotation of the patient from the supine to the left lateral decubitus position. Three of the six patients with asynchronous leaflet closure underwent Cinefluoroscopy, and similar leaflet behavior was documented in all. An atrial systolic wave was inscribed in the valve echogram in six of eight patients with sinus rhythm.Phonocardiography recorded prosthetic valve opening and closing sounds occurring 60 ± 20 ms after aortic closure and 61 ± 12 ms after the QRS complex, respectively. The prosthetic valve opening and closure sound amplitude ratio was 0.11 ± 0.06.A clear plexiglass water bath phantom was fitted to a pulse duplicator and constructed so as to permit in vitro simulation of valve echograms under a variety of conditions. With this method, it was possible to reproduce or approximate all images obtained in patients from both echocardiographic transducer positions.     

Epicardial activation of the human ventricle: Effects of left ventricular hypertrophy

To determine the effects of left ventricular hypertrophy on eplcardlal activation of the human heart, Intraoperative eplcardlal mapping of 40 to 66 points was performed In 10 patients undergoing aortic valve replacement. Mean calculated left ventricular mass was 364 ± 98 g. All patients had normal left ventricular contraction. Earliest eplcardlal activation occurred In the anterior right ventricle In all patients. In 9 patients, it was the only eplcardlal breakthrough point. One patient had a single Inferior left ventricular breakthrough point. Eplcardlal activation spread from the right ventricle towards the left ventricle in both the anterior and inferior direction. Latest eplcardlal activation occurred at the base of the left ventricle In 9 patients and the base of the right ventricle In 1.When compared with patients with coronary artery disease, normal ventricular contraction, and no left ventricular hypertrophy, patients with hypertrophy had fewer left ventricular breakthrough points (p <0.001) and were more likely to have latest activation at the left ventricular base (p <0.001).We conclude that left ventricular hypertrophy Is associated with marked changes In the pattern of epicardlal activation. These changes may reflect delay In spread from endocardium due to the increased wall thickness.     

Plasma apolipoprotein concentrations in familial apolipoprotein A-I and A-II deficiency (Tangier disease)

Familial apolipoprotein A-I and A-II deficiency (Tangier disease) is characterized by cholesterol ester deposition in histiocytes, decreased plasma cholesterol and low density lipoprotein cholesterol (C-LDL), and a striking deficiency of high density lipoproteins (HDL). We measured plasma lipid, lipoprotein cholesterol, and plasma apolipoprotein (apo) A-I, A-II, B, C-I, C-II, C-III, D, and E concentrations in 7 Tangier homozygotes, 2 obligate heterozygotes, and 50 normal subjects. Heterozygotes had modest reductions in high density lipoprotein cholesterol (C-HDL), plasma apoA-I, and apoA-II levels. Mean concentrations (±SD) of plasma C-HDL and apolipoproteins A-I, A-II, B, C-I, C-II, C-III, D, and E in mg% in normals were: 50 ± 14, 134 ± 24, 68 ± 18, 98 ± 20, 7 ± 2, 3.7 ± 2, 13 ± 5, 10 ± 4, and 10 ± 4, respectively; and in homozygotes were: 1 ± 1, 1.3 ± 0.7, 4.8 ± 2.5, 82.6 ± 18, 4.1 ± 1.7, 2.3 ± 0.9, 6.5 ± 3.8, 2.2 ± 0.5, and 5.4 ± 3.1, respectively. Homozygotes had C-HDL, apoA-I and apoA-II levels which were 2%, 1%, and 7% (p < .001) of normal, respectively, and mean levels of apolipoproteins B, C-I, C-II, C-III, D, and E which were 84%, 59%, 62%, 50%, 22%, and 54% of normal, respectively. There was heterogeneity of these latter apolipoprotein concentrations among homozygotes. Mean apoC-I, apoC-III, apoD, and apoE levels were significantly less than normal (pp < .05) in homozygotes. These data indicate that homozygotes have variable but generally decreased apoC and apoE levels, a deficiency of apoD, and a striking reduction in plasma apoA-I and apoA-II concentrations.     

Left ventricular function at high altitude examined by systolic time intervals and M-mode echocardiography

To better understand the effects of high-altitude hypoxia on cardiac performance, healthy lowlandresiding volunteers were studied in 2 groups: 10 subjects after acute ascent to 12,500 ft (3,810 m) (acute group) and 9 subjects after chronic exposure for 6 weeks to 17,600 ft (5,365 m) and 11,000 ft (3,353 m) (chronic group). Systolic time intervals and M-mode echocardiograms were recorded at low and high altitudes. Heart rate was 21% greater at high altitude for all subjects. Preejection period/left ventricular ejection time (PEP/LVET) increased by 16% in the acute group and by 22% in the chronic group. Heart size was smaller at high altitude in both groups, with left atrial and left ventricular (LV) diameters decreasing by 10 to 12%. These changes were statistically significant (p ≤ 0.01). Despite the increase in PEP/LVET, echocardiographic measurements of LV function (percent fractional shortening and mean normalized velocity of circumferential fiber shortening) remained normal. LV isovolumic contraction time was shorter at high altitude, suggesting heightened, rather than depressed, contractility. LV function does not appear to deteriorate at high altitude. Alterations in systolic time intervals probably result from decreased preload, as reflected by smaller heart size, rather than from heart failure or depressed LV contractility.     

Tissue acoustic properties of fresh left ventricular thrombi and visualization by two dimensional echocardiography: Experimental observations

Although two dimensional echocardiography can detect left ventricular thrombi In certain cardiovascular disease states, there Is theoretical concern that the acoustic Impedance properties of recently formed fresh thrombi may not allow their echocardiographic visualization. If such were the case, false negative studies might occur even with technically adequate echocardiographic examinations. To determine if the tissue acoustic properties of acute thrombi allow their visualization and differentiation from surrounding intracavitary blood and adjacent myocardium with two dimensional echocardiography, an in vivo canine model of acute left ventricular thrombus was studied. In 10 dogs left ventricular thrombus was induced using coronary ligation and subendocardial injection of a sclerosing agent, sodium rlclnoleate. Acoustically distinct left ventricular thrombi were imaged by two dimensional echocardiography within hours (mean ± standard deviation 121 ± 40 minutes, range 45 to 180), and the thrombi could easily be differentiated from surrounding blood and adjacent myocardium. Thrombi with a maximal dimension as small as 0.6 cm at autopsy were highly reflective and could be imaged with echocardiography. Histologic examination of the thrombi showed characteristic features of early thrombosis. In six dogs, echocardiographic imaging revealed two acoustically distinct areas of thrombi. Gross and microscopic examination of the thrombi in these animals confirmed two distinct types of thrombus with differing histologie features.Although technical aspects of the echocardiographic examination or certain biologic features of thrombi such as thrombus size may limit the detection of thrombi by echocardiography in certain situations, our data indicate that the tissue acoustic properties of recently formed thrombi are not a primary limitation to their echocardiographic detection. These findings support the use of two dimensional echocardiography in the investigation of the natural history, prevention and therapy of left ventricular thrombus in patients during the early course of acute myocardial Infarction.     

Comparison of multigated radionuclide angiography with ultrasonic sonomicrometry over a wide range of ventricular function in the conscious dog

This study compared the noninvasive assessment of left ventricular function with radionuclide angiography with that obtained with ultrasonic sonomicrometry. Left ventricular ejection fraction and rate of ventricular ejection (dV/dt) were measured with both techniques over a wide range of ventricular function. Six dogs were prepared with epicardlal crystals across the major and minor axes of the left ventricle, paired transmural wall thickness crystals and a left ventricular catheter. The animals were studied while awake after they had recovered from operation. Left ventricular volume was calculated from the ultrasonic sonomicrometric dimension measurements and the equation for a prolate ellipsoid; dV/dt was calculated from the stroke volume and ejection time. Radionuclide angiograms were performed using technetium-99m-labeled red blood cells and an Anger camera with a converging collimator interfaced to a computer programmed for multigated acquisition.A wide range of ventricular function was produced with sequential infusion of isoproterenol, propranolol, phenylepnrine and sodium thiamylal. Ejection fraction and dV/dt were measured simultaneously during each intervention using the time-activity curves of the multigated radionuclide anglogram and ultrasonic sonomicrometric dimensions. Regression analyses demonstrated a close correlation between the simultaneous measurements of ejection fraction (r values ranged from 0.95 to 0.99) and dV/dt (r values ranged from 0.87 to 0.99). these data indicate that noninvasive multigated radionuclide angiography accurately assesses changes in ejection fraction and dV/dt over a wide range of ventricular function.     

Occlusive disease confined to the right coronary artery: Clinical features, surgical treatment and long-term follow-up in 124 patients

The clinical presentation and surgical results in 124 consecutive patients who underwent aorta to right coronary arterial bypass surgery from January 1970 through June 1977 were reviewed. Preoperatively, 75 percent of the patients were in New York Heart Association functional class III or IV, 9 percent presented with unstable angina and 5 percent had life-threatening ventricular arrhythmias. All patients had high grade occlusive disease confined to the right coronary artery; 34 percent of the patients had associated nonsignificant disease (less than 50 percent intraluminal narrowing) of the left anterior descending or circumflex artery. Left ventricular function was normal in 63 percent and minimally impaired in 37 percent. The operative mortality rate was 1.6 percent. The course of the 122 survivors was followed up for 3.7 years. There were four late deaths, and the 5 year mortality rate was 4.0 percent. Eight patients were reoperated on because of recurrence of symptoms and occlusion of the graft or progression of occlusive disease of the other major coronary arteries, or both. Of the remaining 110 patients, 98 are either in functional class I or II, 60 are taking no cardiovascular medications, 52 are working full time without angina and 73 are asymptomatic. In summary, bypass surgery for isolated right coronary artery disease has a low mortality rate and results in excellent long-term symptomatic improvement.     

Histologic diagnosis of diseases of malabsorption

The diagnoses which may be arrived at by examination of peroral small bowel mucosal biopsy specimens are presented. Celiac sprue, unclassified sprue (refractory sprue), infectious gastroenterititis, stasis syndrome and kwashiorkor have a severe mucosal lesion. Other clinical conditions are required to establish the diagnosis in these diseases. A number of diseases have specific diagnostic features. Included are Whipple's disease, abetalipoproteinemia, collagenous sprue, primary intestinal lymphoma, eosinophilic gastroenteritis, giardiasis, coccidiosis, strongyloidiasis, lymphangiectasis and the intestinal immunodeficiency diseases. Mucosal abnormalities may be present in other diseases but the diagnoses are usually made on other criteria than small bowel biopsy. These include vitamin B12 or folic acid deficiency, Crohn's disease, gastrinoma, acrodermatitis enteropathica, amyloidosis, chronic granulomatous disease, lipid storage diseases, histoplasmosis, capillariasis, cytomegalovirus infection, schistosomiasis and macroglobulinemia.