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ABSTRACT: Myocardial function with ultrastructure and high energy phosphate levels in dogs was correlated after 24 hours of sepsis using live Klebsiella aerogenes. All animals developed progressive hemodynamic deterioration over a 24 hour period. Mean arterial pressure decreased from 148 +/- 7 mmHg to 85 (P less than 0.01) and cardiac output decreased from 3.43 +/- .31 to 1.6 +/- 0.5 L/min. Left ventricular stroke work decreased from 48.2 +/- 5 to 18.1 +/- 6 gm-meters (P less than 0.001). Systemic and pulmonary vascular resistances were increased at 24 hours (3,538 +/- 27 to 7,404 +/- 1,400 dyne/sec/cm-5 (P less than 0.01), and 185 +/- 20 and 619 +/- 90 dyne/sec/cm-5 (P less than 0.001), respectively. Left ventricular function curves at 24 hours showed a fixed low output. However, myocardial ultrastructure was preserved and high energy phosphate levels remained normal. These observations correlate well with the changes seen clinically in early gram negative sepsis in hypovolemic patients. Thus, this appears to be a suitable model for further investigation of the effects of gram negative sepsis on myocardial performance, ultrastructure, and maintenance of energy stores.
Journal of the National Medical Association 11/1989; 81(10):1033-40. · 1.16 Impact Factor
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ABSTRACT: In a previous study of 543 patients we developed, using echocardiographic left ventricular mass as the reference standard, two new sets of criteria that improve the electrocardiographic diagnosis of left ventricular hypertrophy (LVH). One set of criteria, which is suitable for routine clinical use, detects LVH when the sum of voltage in RaVL + SV3 (Cornell voltage) exceeds 2.8 mV in men and 2.0 mV in women. The second set of criteria, suitable for use in interpretation of the computerized electrocardiogram, uses logistic regression models based on electrocardiographic and demographic variables with independent predictive value for LVH, with separate equations for patients in sinus rhythm and atrial fibrillation. To test these criteria prospectively with use of a different reference standard, antemortem electrocardiograms were compared with left ventricular muscle mass measured at autopsy in 135 patients. Sensitivity of standard Sokolow-Lyon voltage (SLV) criteria (SV1 + RV5 or RV6 greater than 3.5 mV) for LVH was only 22%, but specificity was 100%. The Cornell voltage criteria improved sensitivity to 42%, while maintaining high specificity at 96%. Higher sensitivity (62%) was achieved by use of the new regression criteria, with a specificity of 92%. Overall test accuracy was 60% for SLV criteria, 68% for the Cornell voltage criteria, and 77% for the new regression criteria (p less than .005 vs SLV). We conclude that the Cornell voltage criteria improve the sensitivity of the electrocardiogram for detection of LVH and are easily applicable in clinical practice.(ABSTRACT TRUNCATED AT 250 WORDS)
Circulation 04/1987; 75(3):565-72. · 14.74 Impact Factor
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ABSTRACT: To evaluate the performance of M-mode echocardiography for detection of pressure-overload left ventricular hypertrophy (LVH), we tested the sensitivity of previously defined sex-specific upper limits of normal echo LV measurements in 31 patients with necropsy-proven pressure-overload LVH and determined the prevalence of LVH detected by each echo criterion in 316 employed patients with uncomplicated hypertension, 100 patients with hypertension evaluated in a referral center, and 38 hospital patients with moderate to severe (WHO class 2) hypertension. Echo measurements were LV mass (LVM), LVM index (LVMI), cross-sectional area (CSA), septal and posterior wall thickness (IVST and PWT), LV internal dimension (LVID), and relative wall thickness (RWT). Prevalences of echo LVH were as follows. (Table: see text). Thus, echo criteria based on LVM are more sensitive than other measurements for detection of necropsy-proven pressure-overload LVH and reveal the highest prevalence of LVH in clinical hypertension populations, and the prevalence of LVH in hypertension is highly dependent on the population studied.
Journal of clinical hypertension 04/1987; 3(1):66-78.
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ABSTRACT: Although echocardiography is more accurate than electrocardiography for detection of left ventricular hypertrophy, it is also more expensive, making it uncertain whether echocardiography is cost-effective for detection of this abnormality in hypertensive patients. Accordingly, the sensitivity of M-mode echocardiographic and electrocardiographic criteria for left ventricular hypertrophy was determined in necropsied patients with anatomic hypertrophy of mild (n = 26), moderate (n = 21) or severe (n = 46) degree, and the prevalence of each degree of hypertrophy was determined in 561 hypertensive adults drawn from clinical and employed population samples. The sensitivity of echocardiographic left ventricular mass index criteria was 57% in necropsied patients with mild hypertrophy and 98% in patients with moderate or severe hypertrophy. All electrocardiographic criteria exhibited lower sensitivity: 15 to 42% for mild, 10 to 38% for moderate, and 30 to 57% for severe hypertrophy. Cost estimates from three sources were $160 for M-mode echocardiography and $48 to $64 for 12-lead electrocardiography. In populations with a 12 to 40% prevalence of hypertrophy, echocardiography was calculated to cost less than electrocardiography per instance of hypertrophy detected ($390-$1013 vs $800-$1829), yielded better separation in predicted incidence of morbid events between hypertensive patients with or without hypertrophy (3.4-4.7 vs 1.5-2.1 per 100 patient-years as opposed to 3.0-4.4 vs 1.9-2.9 per 100 patient-years), and required smaller case and control samples for hypothetical research studies (n = 254-309 vs 397-3478).(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 03/1987; 9(2 Pt 2):II69-76. · 6.21 Impact Factor
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ABSTRACT: To determine which M-mode echocardiographic (echo) measurement best detects left ventricular (LV) hypertrophy, the sensitivity and specificity of upper normal limits of echo LV anatomic measurements (previously shown to have 97% specificity in living normal subjects) were tested in 60 necropsied patients with anatomic hypertrophy and in 28 necropsied patients with normal left ventricles. The prevalence of hypertrophy by each echo criterion was determined in 165 living patients with systemic hypertension, mitral regurgitation or dilated cardiomyopathy. The best separation between patients with normal vs increased necropsy LV mass was obtained using sex-specific echo LV mass index criteria (overall accuracy = 73 of 88 patients, 83%). Lower overall accuracies for separation of patients with and without hypertrophy were observed for echo cross-sectional area (59 of 88 patients, 67%; p less than 0.05 vs LV mass index) and indexes of LV wall thickness (39 to 51%, p less than 0.001). Among 113 living patients with moderate or severe hypertension, mitral regurgitation or dilated cardiomyopathy, LV mass index was increased in 73%, cross-sectional area index in 58% (p less than 0.02 vs LV mass index), and posterior wall thickness, septal thickness and relative wall thickness in only 11 to 32% (all p less than 0.001 vs LV mass index). Thus, an M-mode echo LV mass index of more than 134 g/m2 in men and more than 110 g/m2 in women detects concentric and eccentric LV hypertrophy accurately by comparison with necropsy and clinical reference standards; cross-sectional area is slightly less useful; and other M-mode echo criteria of LV hypertrophy perform too poorly to be clinically applicable.
The American Journal of Cardiology 07/1986; 57(15):1388-93. · 3.37 Impact Factor
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ABSTRACT: To determine the accuracy of echocardiographic left ventricular (LV) dimension and mass measurements for detection and quantification of LV hypertrophy, results of blindly read antemortem echocardiograms were compared with LV mass measurements made at necropsy in 55 patients. LV mass was calculated using M-mode LV measurements by Penn and American Society of Echocardiography (ASE) conventions and cube function and volume correction formulas in 52 patients. Penn-cube LV mass correlated closely with necropsy LV mass (r = 0.92, p less than 0.001) and overestimated it by only 6%; sensitivity in 18 patients with LV hypertrophy (necropsy LV mass more than 215 g) was 100% (18 of 18 patients) and specificity was 86% (29 of 34 patients). ASE-cube LV mass correlated similarly to necropsy LV mass (r = 0.90, p less than 0.001), but systematically overestimated it (by a mean of 25%); the overestimation could be corrected by the equation: LV mass = 0.80 (ASE-cube LV mass) + 0.6 g. Use of ASE measurements in the volume correction formula systematically underestimated necropsy LV mass (by a mean of 30%). In a subset of 9 patients, 3 of whom had technically inadequate M-mode echocardiograms, 2-dimensional echocardiographic (echo) LV mass by 2 methods was also significantly related to necropsy LV mass (r = 0.68, p less than 0.05 and r = 0.82, p less than 0.01). Among other indexes of LV anatomy, only measurement of myocardial cross-sectional area was acceptably accurate for quantitation of LV mass (r = 0.80, p less than 0.001) or diagnosis of LV hypertrophy (sensitivity = 72%, specificity = 94%).(ABSTRACT TRUNCATED AT 250 WORDS)
The American Journal of Cardiology 03/1986; 57(6):450-8. · 3.37 Impact Factor
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ABSTRACT: With the onset of ischemia, the length of myocardial segments increases rapidly, distorting ventricular geometry. Permanent stretching and thinning of infarcted zones have been termed infarct expansion. Although these changes are noted within minutes in vivo, infarct expansion may not be seen for days in postmortem preparations. The apparent postmortem reversal of early infarct expansion suggests that early expansion may be a functional phenomenon, reversible in the early hours of infarction. Alternatively, reversal of expansion may be a postmortem artifact, concealing the importance of underlying structural abnormalities. Myocardial infarction was produced in five dogs by occluding the left anterior descending coronary artery. Ultrasound sonomicrometers were used to measure myocardial segment end-diastolic length in the infarct and normal zones. After 3 hours of ischemia, the heart was arrested in diastole and biopsy specimens were taken from the normal and infarct zones. Sarcomere length was measured from electron photomicrographs, and myofiber width was measured from light photomicrographs. After 3 hours of ischemia, infarct zone segment length had increased significantly more than normal zone length (116 +/- 11 [SD] versus 103 +/- 4% of control length, p less than 0.05), whereas 2 minutes after cardiac arrest, both the infarct and normal zones returned to preischemic segment length, demonstrating apparent reversibility of early infarct expansion. However, histologic study revealed that the infarct zone myofibers were significantly thinner than normal zone myofibers (7.9 +/- 0.3 versus 9.4 +/- 0.3 micron, p less than 0.001) and sarcomere length in the infarct zone was significantly longer than that in the normal zone (1.9 +/- 0.2 versus 1.5 +/- 0.2 micron, p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)
Journal of the American College of Cardiology 11/1985; 6(4):839-44. · 14.16 Impact Factor
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ABSTRACT: High-potassium cardioplegic solutions (CSs) may induce endothelial cell damage in vascular grafts, promoting graft thrombosis after coronary bypass operations. We studied prostacyclin (PGI2) production by saphenous veins as a marker of endothelial cell function in a model mimicking actual operative conditions. Fresh saphenous vein segments from patients who had undergone coronary bypass were cut in half; each part was perfused and incubated sequentially with CS (with 20, 40, or 80 mEq potassium/L) or a control buffer (5 mEq potassium/L) at 4 degrees C for 30 minutes (perfusion I), buffer at 37 degrees C for 15 minutes (perfusion II), and buffer plus 25 microM sodium arachidonate at 37 degrees C for 15 minutes (perfusion III). This permitted evaluation of changes in PGI2 production during or after exposure to CS, in basal and stimulated conditions. CS with 20 mEq potassium/L did not alter PGI2 production as compared with control buffer. CS with 40 mEq potassium/L decreased PGI2 production during perfusions I and II. CS with 80 mEq potassium/L also decreased sodium arachidonate-stimulated PGI2 production. Endothelial coverage (immunoperoxidase staining for factor VIII antigen) was intact at all potassium concentrations tested. Thus potassium in CSs can depress endothelial PGI2 production without causing immediate endothelial detachment. This effect may favor thrombosis in bypass grafts.
Surgery 10/1985; 98(3):465-71. · 3.10 Impact Factor
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ABSTRACT: Mice of the autoimmune, lymphoproliferative strain MRL/lpr and the congenic, nonlymphoproliferative strain MRL/n were fed one of six diets from weaning on-ward. These mice were sacrificed at 3 or 5 months of age. Low fat diets resulted in lower cholesterol and higher triglyceride levels than did cholesterol-containing high-fat diets. Caloric restriction of MRL/lpr mice was associated with an increased plaque-forming cell response to trinitrophenylated polyacrylamide beads, less lymphoproliferation, and less severe glomerulonephritis. Diet did not affect the incidence of autoimmune vasculitis in MRL/lpr mice sacrificed at 5 months. MRL/lpr mice fed a low-fat, calorically restricted diet from 5 months of age to death lived longer than mice which were fed ad libitum a cholesterol-containing, high-fat diet. At death, MRL/lpr mice fed the former diet had the autoimmune vasculitis which had been evident in mice killed at 5 months, whereas mice fed the latter diet, in addition to the vasculitis, had a high incidence of atherosclerotic lesions of intrarenal and aortic branch arteries.
American Journal Of Pathology 11/1984; 117(1):110-24. · 4.89 Impact Factor
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ABSTRACT: Mice of the autoimmune strain MRL/1, the congenic strain MRL/n, and two control strains, Balb/c and C57BL/6 mice, were fed diets which varied in the content of lipid and cholesterol. Serum cholesterol levels were highest in mice fed diets containing cholesterol and lowest in mice fed laboratory "chow." Animals fed diets that increased serum cholesterol had decreased production of prostacyclin by vascular tissue and increased production of thromboxane A2 by platelets. Prostacyclin production by heart tissue in response to arachidonic acid showed a negative correlation (r = -0.86) with serum cholesterol. In contrast, serum thromboxane demonstrated a positive correlation (r = 0.70) with serum cholesterol. The prevalence of autoimmune vasculitis seen in MRL/lpr mice was not affected by diet. However, MRL/lpr mice fed a high-fat, cholesterol-containing diet had intimal vascular lesions containing foam cells typical of arteriosclerosis. It is suggested that diets that raise serum cholesterol may influence the nature of autoimmune-mediated vascular disease by altering the balance between thromboxane and prostacyclin.
American Journal Of Pathology 11/1984; 117(1):125-30. · 4.89 Impact Factor
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ABSTRACT: This study correlated the location and size of posterolateral myocardial infarcts (MIs) measured anatomically with that estimated by quantitative criteria derived from the standard 12-lead ECG. Twenty patients were studied who had autopsy-proved, single, posterolateral MIs and no confounding factors of ventricular hypertrophy or bundle branch block in their ECG. Left ventricular anatomic MI size ranged from 1 to 46%. No patient had a greater than or equal to 0.04-second Q wave in any electrocardiographic lead and only 55% had a 0.03-second Q wave. A 29-point, simplified QRS scoring system consisting of 37 weighted criteria was applied to the ECG. Points were scored by the ECG in 85% of the patients (range 1 to 8 points). MI was indicated by a wide variety of QRS criteria; 19 of the 37 criteria from 8 different electrocardiographic leads were met. The correlation coefficient between MI size measured anatomically and that estimated by the QRS score was 0.72. Each point represented approximately 4% MI of the left ventricular wall.
The American Journal of Cardiology 04/1984; 53(6):706-14. · 3.37 Impact Factor
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ABSTRACT: Repeat cardiac surgery is significantly more difficult than the original surgery. Pericardial closure to limit adhesion formation between the heart and mediastinal structures and thus reduce the increased difficulty of reoperation has been considered. To investigate the feasibility of effecting loose pericardial closure with homologous pericardial grafts, glutaraldehyde-preserved pericardial allografts were implanted in 10 mongrel dogs. After a mean period of 6.7 months (range 6 to 8 months) the grafts were studied grossly and histologically. Adhesion formation was minimal and the adhesions were easily dissectible. The allografts evoked no significant inflammatory response. No infections resulted from graft placement. It is concluded that glutaraldehyde-preserved pericardial allografts may be useful to effect pericardial closure and deserve further investigation in this regard.
Journal of Surgical Research 02/1984; 36(1):50-4. · 2.25 Impact Factor
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S F Roark,
R E Ideker,
G S Wagner, D R Alonso,
S P Bishop,
C M Bloor,
D A Bramlet,
J E Edwards,
J T Fallon,
G J Gottlieb,
D B Hackel,
H R Phillips,
K A Reimer,
W J Rogers,
W K Ruth,
R M Savage,
R D White,
R H Selvester
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ABSTRACT: This study evaluated by quantitative autopsy correlation a previously developed scoring system for estimating the size of myocardial infarcts based on the QRS complex of the electrocardiogram. This system was tested using electrocardiograms from patients with infarcts shown by autopsy to predominate in the inferior third of the left ventricle. The study was limited to patients whose electrocardiogram did not indicate left or right ventricular hypertrophy, left or right bundle branch block, or left anterior or posterior fascicular block. Thirty-one patients from 6 medical centers met these criteria. In the electrocardiogram of 28 of the 31 patients (90%), lead a VF exhibited a Q wave of at least 30 ms. The correlation coefficient between the total QRS score and the percent infarction of the left ventricle was 0.74. In patients without confounding factors in the electrocardiogram and with single infarcts, the electrocardiogram provides a marker for infarcts in the inferior third of the left ventricle and a quantitative QRS scoring system provides an estimate of infarct size.
The American Journal of Cardiology 03/1983; 51(3):382-9. · 3.37 Impact Factor
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ABSTRACT: Autoimmune-prone B/W mice, which are known to develop severe glomerulonephritis and vasculitis, also are found to develop arteritis and proliferative and fatty-proliferative lesions of the aorta and its branches as well as renal inflammatory lesions. High intake of saturated fat in the diet enhances the development of these atherosclerotic and autoimmune lesions significantly in female mice, whereas restriction of dietary calories and fat inhibits their development. Ad lib feeding of laboratory chow, high in fiber and low in fat, does not foster development of vascular lesions but does permit the development of autoimmune renal disease.
Proceedings of the National Academy of Sciences 03/1983; 80(3):874-7. · 9.68 Impact Factor
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R E Ideker,
G S Wagner,
W K Ruth, D R Alonso,
S P Bishop,
C M Bloor,
J T Fallon,
G J Gottlieb,
D B Hackel,
H R Phillips,
K A Reimer,
S F Roark,
W J Rogers,
R M Savage,
R D White,
R H Selvester
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ABSTRACT: The ability of an independently developed QRS point score to estimate the size of infarcts predominantly within the anterior third of the left ventricular was evaluated by quantitative pathologic-electrocardiographic correlation. The study was limited to 21 patients with a single infarct documented by postmortem examination, for whom an appropriately timed standard 12 lead electrocardiogram was available that did not exhibit signs of left or right ventricular hypertrophy, left or right bundle branch block or anterior or posterior fascicular block. At necropsy the heart was cut into five to seven slices. The location and size of the infarct was quantitated by computer-assisted planimetry of the slices. The electrocardiogram of 19 (90 percent) of the patients exhibited either a Q wave or an R wave of no more than 20 ms in lead V2. The infarct in the two patients without this electrocardiographic finding was small, occupying 2 and 3 percent of the left ventricle, respectively. The percent infarction of the left ventricle correlated with the QRS point score (r=0.80). Thus in patients without complicating factors in the electrocardiogram and with a single infarct, the electrocardiogram provides a marker for infarction in the anterior third of the left ventricle and permits estimation of infarct size.
The American Journal of Cardiology 06/1982; 49(7):1604-14. · 3.37 Impact Factor
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ABSTRACT: Although patients with acute inferior myocardial infarction often manifest S-T segment depression in precordial electrocardiographic leads, the pathophysiologic abnormalities associated with this finding are poorly understood. To examine this problem, electrocardiographic findings on admission were compared with results of radionuclide cineangiography performed within 38 hours of the onset of symptoms in 25 patients with inferior infarction. Summation of S-T depression in leads V1 through V4 permitted the separation of patients into two groups: Group A (11 patients with 0.20 mV or less of S-T depression) and Group B (14 patients with 0.45 vM or more of S-T depression). The radionuclide cineangiogram revealed inferior wall dysfunction in all patients. Additional posterolateral dysfunction was seen in 13 patients, all in Group B. Patients in Group B had a relatively larger infarction (peak creatine kinase Units - 756 +2- 358 in Group A versus 1,566 +/- 983 units in Group B, p less than 0.01) and greater functional impairment (ejection fraction - 45 +/- 12 in Group A versus 33 +/- 12 in Group B, p less than 0.01). The relation between precordial S-T segment depression and posterolateral dysfunction appears to be largely independent of electrocardiographic evidence of "true posterior infarction." Thus moderate or severe anterior precordial S-T depression in patients with acute inferior infarction is a sensitive and specific indicator of relatively extensive myocardial damage, primarily involving the posterolateral region.
The American Journal of Cardiology 01/1982; 48(6):1009-15. · 3.37 Impact Factor
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ABSTRACT: Arteries are capable of producing significantly larger quantities of prostacyclin than are veins. To test the hypothesis, whether prostacyclin production by the vessel wall is related to blood pressure and flow, we measured the amounts of PGI2 released and synthesized by venous segments transplanted for 6 weeks into the arterial circulation. These results were compared with the production of prostacyclin by normal veins and arteries. In 20 dogs a segment of jugular vein was interposed into the carotid system; a sham dissection was done on the opposite side. "Arterialized" vein grafts showed prominent intima lined by endothelium, medial smooth muscle cell proliferation and fibrotic proliferation in adventitia. Spontaneous and arachidonic acid-stimulated prostacyclin production (measured by radioimmunoassay for 6-keto-PGF1 alpha) was not significantly different between arterialized venous autografts and jugular veins. Significantly larger amounts of prostacyclin were synthesized by the carotid artery. Thus, histologic changes and rheologic effects occurring in vein grafts transposed to the arterial site do not affect prostacyclin production.
Prostaglandins 10/1981; 22(3):485-98.
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ABSTRACT: The existence of a border zone composed of reversibly injured myocardium surrounding an evolving infarct has been the subject of controversy. In experiments designed to search for such a border zone by electron microscopy, 12 mongrel dogs underwent permanent ligation of the left anterior descending coronary artery (LAD). Two to 6.5 (average = 4.2) hours later, the hearts were excised, the area at risk (myocardium perfused by the LAD) was outlined by injection of fluorescent microspheres, and the myocardial infarct was demonstrated by the nitro blue tetrazolium (NBT) gross histochemical method. Myocardial samples for electron-microscopic study were obtained from the periphery of the infarct (tissues unstained by NBT) and serially from the immediately adjacent myocardium, which was stained deep blue by NBT. Grossly, the infarcts always involved the subendocardial myocardium, extended for a variable distance in the epicardial direction, and closely approximated the lateral margins of the area at risk. When examined by electron microscopy, the infarct periphery showed evidence of irreversible damage, thus confirming the ability of NBT to detect early myocardial necrosis. Multiple samples of the NBT-stained myocardium immediately adjacent to the infarct showed varying degrees of reversible ischemia, thus demonstrating, at the ultrastructural level, the existence of a border zone of intermediate myocardial injury. This border zone was substantial (3--4 mm in width) along the subepicardial aspect of the infarct and very thin (1--2 mm) laterally. In conclusion, a significant border zone was demonstrable by electron microscopy in the subepicardial myocardium of 8 out or 12 canine hearts with recent coronary artery occlusion. In the remaining 4 hearts, the infarcts had already reached the epicardium at the time of study, and only a thin lateral border zone was present.
American Journal Of Pathology 06/1981; 103(2):292-303. · 4.89 Impact Factor
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ABSTRACT: Electrocardiographic criteria have been derived from vectorcardiographic and angiographic correlation which allow division of patients with electrocardiographic "poor R-wave progression" or "reversed R-wave progression" into the following four etiologic groups: (1) anterior myocardial infarction; (2) left ventricular hypertrophy; (3) type-C right ventricular hypertrophy; and (4) the normal variant. The sensitivity, specificity, and predictive value of this approach to the electrocardiogram with poor or reversed R-wave progression were studied in a series of 33 patients examined at autopsy. Using the scheme and criteria outlined, 85 percent (11/13) of the pathologic anterior myocardial infarctions were correctly diagnosed. The electrocardiographic criteria correctly identified 75 percent (15) of 20 patients with poor or reversed R-wave progression without postmortem evidence of myocardial infarction, with only 12 percent (2/17) predictive error. The relative risk of autopsy-documented anterior myocardial infarction in patients meeting the specified electrocardiographic criteria was six times that of other patients with poor or reversed R-wave progression.
Chest 03/1981; 79(2):195-200. · 5.25 Impact Factor
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ABSTRACT: An isolated-heart preparation has been adapted to permit rapid evaluation of, and imaging by, myocardial tracers. The rabbit heart provided a mass large enough for imaging and serial biopsies. Coronary arteries could be selectively ligated and provided landmarks for epicardial ST segment mapping. Uptake ratios between a tissue sample and normal myocardium (T/N), obtained using Tc-99m glucoheptonate as an infarct-seeker, increased with duration of the ischemic period, which was followed by reflow. After 25 min of occlusion the T/N was 4.5; after 40 min T/N = 6; after 60 min T/N = 8; and after 120 min T/N = 19. This well-controlled adjunct to in vivo studies allows evaluation of myocardial imaging agents without interfering with systemic effects or blood and tissue background. Functional and structural changes can be sequentially measured and correlated with the localization of various radiopharmaceuticals.
Journal of Nuclear Medicine 07/1980; 21(6):523-8. · 6.38 Impact Factor
