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Noninvasive assessment of cardiac risk in insulin-dependent diabetic patients being evaluated for pancreatic transplantation using thallium-201 myocardial perfusion scintigraphy.

We examined the value of thallium-201 myocardial perfusion scintigraphy in noninvasive assessment of cardiac risk in 36 insulin-dependent (type 1) diabetic patients being evaluated for pancreas or combined pancreas/kidney transplantation. An extensive cardiovascular evaluation including electrocardiogram was performed in all patients, and most patients were also evaluated by two-dimensional and Doppler echocardiography. Exercise thallium studies were performed in 31 patients. Five patients were unable to exercise and underwent dipyridamole-thallium study. The thallium images were abnormal in 12 patients, 10 of whom underwent coronary arteriography. Significant coronary artery disease was found in 7 of these patients. Nineteen patients underwent pancreatic (3 patients) or pancreato-renal (16) transplantation without any occurrence of cardiac death or nonfatal myocardial infarction peri-operatively or on follow-up ranging from 7 months to 21 months. In contrast, 3 cardiac events occurred in 12 patients not approved for transplantation, each of whom had an abnormal thallium study exhibiting significant ischemia. Resting left ventricular global and regional function was not helpful in determining perioperative risk. Thus, thallium-201 myocardial perfusion scintigraphy may be useful in identifying diabetic patients at low risk for pancreas transplantation and may obviate the need for routine coronary angiography in these patients.

Adult↗

Comparison of ischemic patterns in myocardial bridge and syndrome X: evaluation by dobutamine stress echocardiography and stress thallium-201 SPECT.

BACKGROUND AND PURPOSE: Ischemic patterns in patients with syndrome X are thought to differ from those in patients with myocardial bridge, because the mechanisms of coronary flow reduction in these two diseases are different. The aim of this study was to compare the ischemic patterns in patients with syndrome X and those with myocardial bridge through the use of dobutamine stress echocardiography (DSE) and stress thallium-201 single-photon emission computed tomography (SPECT). METHODS: Twenty-six patients with typical angina and stress-induced ST-segment depression were enrolled. All patients underwent coronary angiography, DSE, and stress thallium-201 SPECT within 7 days after enrollment. RESULTS: Of the 26 patients enrolled, 10 had myocardial bridge of the left anterior descending artery and 16 had syndrome X. Among patients with myocardial bridge, myocardial dyssynergy was found by DSE in five patients and reversible or fixed thallium-201 perfusion defects were found in four. Seven patients with myocardial bridge had reverse redistribution patterns on thallium-201 scintigraphy. In the 16 patients with syndrome X, myocardial dyssynergy was found by DSE in only one patient (p = 0.018 vs myocardial bridge group) and reversible or fixed thallium-201 perfusion defects were found in nine (p > 0.05 vs myocardial bridge group). Four patients with syndrome X had reverse redistribution patterns on thallium-201 scintigraphy. The resting left ventricular end-diastolic pressure was higher in patients with myocardial bridge than in those with syndrome X (17 +/- 4 vs 12 +/- 5 mm Hg, p = 0.02). CONCLUSIONS: The most common ischemic patterns in patients with syndrome X were chest pain and stress-induced ST-segment depression, followed by myocardial perfusion defects. Dobutamine-induced dyssynergy was rare. Left ventricular end-diastolic pressure elevation and dobutamine-induced wall motion abnormalities were more common in patients with myocardial bridge than in those with syndrome X.

Adult↗

[Thallium intoxication treated by hemodialysis, forced diuresis and antidote (author's transl)].

Mode of action and toxicity of thallium and former treatment of thallium intoxication are described. A case of thallium poisoning with a lethal dose of thallous sulfate which was successfully treated by hemodialysis, forced diuresis and antidote is reported. 43 percent of the thallium could be eliminated by continuous hemodialysis during 72 hours and forced diuresis within the third and seventh day after ingestion of the poison. The dialysance of thallium was 111,1 ml/min with a blood flow of 200 ml/min. Later damage can be prevented by early maximal elimination of thallium.

Adenosine Triphosphatases↗

[Thallium poisoning induced polyneuropathy--clinical and electrophysiological data].

INTRODUCTION: The aim of the study was the electrophysiological investigation of thallium induced polyneuropathy. Beyond the rarity of the illness, the motivation of this work was the possibility of following up the pattern of neuronal damage. Thallium is one of the most toxic heavy metal and its wide use increases the chance of chronic or accidental acute poisoning. The entero-hepatic circulation makes the accumulation of this toxic agent in tissues possible, mostly in neurons, in the epithelial cells of the digestive tract, in the germinative cells of the skin and testicles. In addition to alopecia and digestive complaints, the clinical picture of thallium poisoning is dominated by neurological signs. Severe axonal polyneuropathy develops in almost all cases, with further damage to the retina and impairment of cognitive functions being not unusual. The diagnosis is confirmed by finding high levels of thallium in body fluids, especially in saliva and urine. CASE REPORT: Electrophysiological examination of our accidentally poisoned patient revealed severe, sensory-motor, predominant motor axonal polyneuropathy and pointed out some aspects of the pattern of neurotoxic process: the initially distal lesion, the dying-back course and the capacity for regeneration. CONCLUSION: Because thallium has the same molecular targets as potassium ion thus impairing the energetical supply of the nerve cell, the most effective treatment is carefully loading with potassium. If recognized and treated early, thallium poisoning has a favourable prognosis.

Diagnosis, Differential↗

Identification of viable myocardium in patients with chronic coronary artery disease: comparison of thallium-201 scintigraphy with reinjection and technetium-99m-methoxyisobutyl isonitrile.

We compared the results of 201Tl reinjection and those of 99mTc-methoxyisobutyl isonitrile (MIBI) in identifying viable myocardium in 20 male patients with angiographically proven coronary artery disease (CAD) and left ventricular dysfunction (ejection fraction 30% +/- 8%). All patients had irreversible defects on standard exercise-redistribution thallium imaging. Thallium was reinjected immediately after the redistribution study, and images were reacquired. The patients also underwent stress and rest 99mTc-MIBI myocardial scintigraphy (2-day protocol). A total of 300 myocardial regions were analyzed, of which 122 (41%) had irreversible thallium defects on redistribution images before reinjection. Of the 122 myocardial regions with irreversible defects on standard stress-redistribution thallium cardiac imaging, 65 (53%) did not change at reinjection and 57 (47%) demonstrated enhanced uptake of thallium after reinjection. Of the same 122 irreversible defects on stress-redistribution thallium, 100 (82%) appeared as fixed defects and 22 (18%) were reversible on 99mTc-MIBI myocardial scintigraphy. These data indicate that 201Tl cardiac imaging with rest reinjection is superior to 99mTc-MIBI myocardial scintigraphy in identifying viable myocardium in patients with chronic CAD, suggesting that regions with severe reduction of 99mTc-MIBI uptake both on stress and rest images may contain viable myocardium.

Adult↗

[Determination of trace thallium by platform-GFAAS after preconcentration with polyurethane foam].

OBJECTIVE: To develop a method for trace thallium determination. METHODS: Thallium (L) was oxidized to thallium (III) by bromine water and the thallium (III) was complexed to [TlCl4]- in 20 mL/100 mL HCI and absorbed by polyurethane foam. The adsorbed thallium was eluted by a boiling water bath and determined by platform-GFAAS. Tl (III) could be analyzed directly and the total Tl be analyzed after oxidation, so speciation could be achieved. RESULTS: In the range of 5-100 ng/mL the linear equation was y = 0.013x + 0. 012 with the regression coefficient 0.996. The relative standard deviation was 4.7% for the standard solution of 5.00 ng/mL and the recoveries of water samples were in the range of 95.7%-104.5%. CONCLUSION: The proposed method could determine trace thallium as low as 0.02 ng/mL.

Adsorption↗

[Analysis using scintigraphy with thallium-201 of the perfusion picture before and after myocardial revascularization].

The present study was undertaken to investigate the effects of coronary artery bypass surgery on myocardial perfusion analyzed by thallium-201 scintigraphy. In 34 patients early thallium-201 imaging, repeated 4 hours later at rest, was performed 2-3 days before and within 1 year following myocardial revascularization. Before surgery, exercise ECGs were positive in 22/34 patients, with scintigraphic perfusion defects in 33/34 patients; thallium-201 imaging showed reversible in 77 and irreversible perfusion defects in 51 myocardial segments. After surgery, exercise ECGs were positive in 3/34 patients, while thallium-201 perfusion data improved in 27, were unchanged in 4 and worsened in 3 patients. After surgery, thallium-201 imaging showed a remarkable improvement, with decreased number of reversible (8 segments) and irreversible (32 segments) perfusion defects. Ten of the 22 patients with previous myocardial infarction had improved irreversible perfusion defects in myocardial segments that were infarcted. Qualitative thallium-201 scintigraphy showed that myocardial revascularization exerted a clear favorable influence on reversible perfusion defects and in part on irreversible perfusion defects, suggesting that persistent defects are compatible not only with scar tissue, but also may represent hypoperfusion of viable myocardium.

Adult↗

Isoproterenol stress thallium scintigraphy for detecting coronary artery disease.

The value of exercise thallium scintigraphy in detecting coronary artery disease is well established. However, there are at times situations in which the exercise test cannot be readily used. Isoproterenol (ISP) stress ECG (ISP-ECG) is reportedly a useful method in diagnosing coronary artery disease. In the present study, we assessed the diagnostic value of ISP thallium scintigraphy, comparing it with those of ISP-ECG and exercise thallium scintigraphy. The study population consisted of 24 patients who had histories of chest pain without previous myocardial infarction. ISP was given at increasing doses of 0.02, 0.04, 0.08 micrograms/kg/min at 3-minute intervals, and was terminated for any of the following reasons: angina, significant arrhythmia, significant ST segment depression (greater than or equal to 0.1 mV) or target heart rate. Thallium scintigrams were obtained immediately after terminating ISP infusion, and after a 3-hour delay, redistribution scans were obtained. Scintigrams were considered positive when a reversible defect was present. In nine patients who underwent exercise tests, exercise thallium scintigraphy was also performed. After the stress tests, coronary angiography was performed. According to the presence or absence of significant coronary artery stenosis (greater than or equal to 75%), all subjects were divided into two groups: coronary artery disease (CAD) group (n = 12) and so-called normal coronary (NC) group (n = 12). 1. Among 12 patients in the CAD group, ISP induced anginal pain in six (50%), and ISP-ECG and ISP thallium scintigraphy were positive in 10 (83%) and in 11 (92%), compared with four (33%), four (33%) and two (17%) in the NC group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Comparative analysis of the diagnostic and prognostic value of exercise ECG and thallium-201 scintigraphic markers of myocardial ischemia in asymptomatic and symptomatic patients.

A considerable amount of data now exists that indicates that exercise ECG--due to its suboptimal sensitivity and specificity--has limited diagnostic and prognostic value in asymptomatic subjects, patients with chest pain of unclear etiology or those with chronic stable angina pectoris, and in patients recovering from acute myocardial infarction. Because of this and the well-recognized advantages of thallium-201 scintigraphy, there appears to be a strong rationale for recommending exercise perfusion imaging, rather than exercise ECG alone, as the preferred method for detecting CAD and staging its severity. This recommendation seems justified given the fact that (1) thallium-201 scintigraphy is far more sensitive and specific in detecting myocardial ischemia than exercise testing; (2) unlike stress ECG, thallium-201 scintigraphy can localize ischemia to a specific area of areas subtended by a specific coronary artery; and (3) thallium-201 scintigraphy has been shown to be more reliable to risk stratification of individual patients than exercise testing alone. The more optimal prognostic efficiency of thallium-201 scintigraphy is due, in part, to the fact that the error rate in falsely classifying patients as low-risk is substantially and significantly smaller with thallium-201 scintigraphy than with stress ECG.

Coronary Disease↗

Non-invasive diagnosis of ischemic heart disease using stress thallium scintigraphy and digital exercise 2-dimensional echocardiography.

The introduction of computer technology has overcome many of the technical difficulties in performing and interpreting echocardiograms obtained from exercising individuals and has made stress echocardiography a potentially practical examination. Additional data, however, are necessary to establish the accuracy of exercise echocardiography. The purpose of this study is to compare exercise echocardiography and planar thallium studies for accuracy in detecting coronary artery disease. The study was performed on 50 patients, 41 of whom underwent coronary angiography. For the remaining 9 patients accuracy was defined as concordance of clinical information, treadmill ECG results, thallium data and the exercise echocardiogram. If there was any discrepancy among these tests, the patient was not included in the analysis. The sensitivity of exercise 2D digital echocardiography was comparable to stress thallium (0.86 vs 0.85) and was better than treadmill test alone (0.66). There were no false positive tests with echocardiographic study, while 1 false positive thallium examination was detected. The diagnostic accuracy of stress echocardiography was 0.90, stress thallium 0.85 and treadmill test only 0.75. In conclusion, exercise echocardiography appears to give results comparable to stress planar thallium studies. In addition, the ultrasonic procedure has several advantages: it is totally non-invasive, does not require a reperfusion study 4 hours later, avoids radiation and is less expensive.

Adult↗

A comparison of dipyridamole-thallium imaging and exercise testing in the prediction of postoperative cardiac complications in patients requiring arterial reconstruction.

The individual and combined predictive values of dipyridamole-thallium imaging and exercise testing were compared in a prospective study of 70 patients who had abdominal aortic aneurysms or aortoiliac occlusive disease that required surgical repair. All patients were evaluated clinically by the same cardiologist and had exercise stress testing and dipyridamole-thallium imaging before admission for surgery. Ten patients were excluded from the study because they had evidence of severe ischemia when tested (ST segment depression greater than 2 mm on exercise testing, severe multivessel disease on thallium imaging). The remaining 60 patients were operated on (abdominal aortic aneurysm repair, 40; aortobifemoral repair, 17; femorofemoral graft, 3). The test results were withheld from the surgeon, anesthetist, and cardiologist before surgery. A total of 22 patients experienced major cardiac complications postoperatively (acute pulmonary edema, 17; acute myocardial, infarction, 5; cardiac death, 2). Thallium imaging showed myocardial ischemia in 31/60 patients. Exercise testing was positive (greater than or equal to 1 mm ST segment depression) in 10/60 patients. Dipyridamole-thallium imaging with a high sensitivity and reasonable specificity is the initial test of choice. Exercise testing is a poor screening test because of its low sensitivity. The combination of the two tests gives the highest positive predictive value and the greatest likelihood ratio. Thus patients assessed initially and found to have positive thallium scan results may be further stratified by exercise testing.

Adult↗

[Myocardial perfusion in coronary disease: thallium-201 planar scintigraphy].

This research evaluated the diagnostic and analytic effectiveness of 201-thallium imaging in a group of patients with coronary artery disease, each one of them with different localization, extent and number of coronary vessel obstructions. The thallium-201 imaging was performed immediately after ergometric test and repeated 4 hours later. In a large percentage of patients thallium-201 imaging of reversible and irreversible perfusion defects have been found; thallium-201 scintigraphy showed a greater sensitivity than exercise ECG. With particular evidence 201-Tl imaging showed perfusion defects in a high percentage of patients with obstruction of one and two coronary vessels; in these patients, in the former especially, the results of exercise ECGs showed a lower sensitivity. Both thallium-201 and exercise ECG had a similar sensitivity in patients with obstruction of three coronary vessels. In patients with obstruction of one or two vessels, thallium-201 imaging clearly showed a regional hypoperfusion corresponding to the specific perfusion coronary vessels, while exercise ECG gave aspecific topographic results. Irreversible perfusion defects resulted corresponding to the myocardial segments that were infarcted, but were also observed in patients without previous myocardial infarction.

Adult↗

Detection of multivessel disease in patients with sustained myocardial infarction by thallium 201 myocardial scintigraphy: no additional value of quantitative analysis.

This study was performed to determine the value of visual and quantitative thallium 201 scintigraphy for the detection of multivessel disease in 67 patients with a sustained transmural myocardial infarction. Also the viability of the myocardial regions corresponding to pathologic Q-waves was evaluated. Of the 67 patients, 51 patients had multivessel coronary artery disease (76%). The sensitivity of the exercise test was 53%, of thallium scintigraphy 69%, when interpreted visually, and 67%, when analysed quantitatively. The specificity of these methods was 69%, 56%, and 50%, respectively. Sixty-two infarct-related flow regions were detected by visual analysis of the thallium scans, total redistribution was observed in 11/62 (18%) of patients, partial redistribution in 26/62 (42%), and no redistribution in 25/62 (40%) of patients. The infarct-related areas with total redistribution on the thallium scintigrams were more likely to be associated with normal or hypokinetic wall motion (7/11: 64%) than the areas with a persistent defect (7/25:28%) (P = 0.05), which were more related with akinetic or dyskinetic wall motion. Based on our results, it is concluded that 1) both visual and quantitative analysis of thallium exercise scintigraphy have limited value to predict the presence or absence of multivessel coronary artery disease in patients with sustained myocardial infarction, and 2) exercise-induced thallium redistribution may occur within the infarct zone, suggesting the presence of viable but jeopardized myocardium in presumed fibrotic myocardial areas.

Coronary Angiography↗

[Myocardial involvement in female Fabry's disease: evaluation by thallium-201 myocardial scintigraphy].

Fabry's disease is characterized by an inherited X-linked disorder of glycosphingolipid catabolism, and heterozygous women affected with this disease who show overt symptoms including cardiac manifestations have rarely been reported. To elucidate the features of myocardial involvement in female patients, noninvasive techniques including exercise stress thallium-201 myocardial scintigraphy were performed. Three female patients, Cases 1-3, 26, 29 and 50 years of age, were documented low leucocytic alpha-galactosidase activities of less than 48% of normal (67.92-16.2 nmol/mg protein/h). They were examined using ECG, two-dimensional echocardiography (2-D Echo), Holter ECG, treadmill test and stress scintigraphy. On the ECG, negative T waves were shown in leads III and aVF in Cases 1 and 2. Left ventricular high voltage, giant negative T waves and short PR intervals were seen in Case 3. The 2-D Echo revealed neither valvular change nor left ventricular hypertrophy. On the Holter ECG, monofocal ventricular premature beats were occasionally observed in Cases 1 and 3. The treadmill test showed positive ST changes only in Case 2. On the exercise stress scintigraphy, uptake of thallium-201 was enhanced in the apex of the heart in Cases 2 and 3. Low uptake areas of thallium-201 were observed in Case 3. The ventricular angiogram revealed slight hypertrophy of the wall of the apical portion. In endocardial biopsies from the right ventricle, myelinoid lamellar inclusions were demonstrated in myocardial cells electron microscopically. Increased uptake of thallium-201 in the apex was noted in two of the three patients, but no apical thickening was noticed in any of the three cases by 2-D Echo. From the result of the biopsy of Case 3, the increased apical uptake of thallium-201 seems to reflect thickening caused by the deposition of glycosphingolipid. It was concluded that myocardial involvement in female Fabry's disease may occur early in the third decade and that the lesions could be detected with high sensitivity by thallium-201 myocardial scintigraphy.

Adult↗

[Cardiac inotropic reserve examined by postextrasystolic potentiation and redistribution of exercise thallium-201 scintigraphy].

Evaluation of regional contractile reserve and the viability of an infarcted segment of the myocardium is very important in determining the indications for aorto-coronary bypass after myocardial infarction and in predicting the prognosis. Regional wall motion of the left ventricle after postextrasystolic potentiation (PESP) was studied in 18 patients with old myocardial infarction, and compared with indices of redistribution of thallium after exercise. Equilibrium radionuclide angiocardiography (RNA) using Tc99m HSA was performed at rest and after PESP produced by a programmable cardiac stimulator via a right ventricular catheter. Regional ejection fractions (REF) were determined, and wall motion was observed visually. The relative thallium activity (RTA) and washout rate (WOR) were obtained from exercise myocardial scintigraphy performed 10 minutes, and 3 hours after thallium-201 injections. Wall motion improved in 12 of 23 infarcted segments after PESP. Regional ejection fraction and relative thallium activity (in three hours, or the difference between the activities of the initial and three hours after exercise) in the improved segments were significantly higher (p less than 0.001) than in the unchanged segments. Washout rate was lower (p less than 0.02) in the improved segments. Significant correlation was observed between the change in regional ejection fraction and relative thallium activity (3 hours after exercise) (r = 0.654, p less than 0.05). Thus, the wall motion of some infarcted regions of the myocardium improved after PESP, and thallium was redistributed during three hours after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise Test↗

Thallium as an industrial poison (review of literature).

The presented reports on cases of occupational thallium poisoning clearly demonstrate that the possibility of their occurrence in industrial plants is very real. The number of such intoxications is much higher than that of non-industrial poisonings, but this is predominantly due to the less pronounced clinical picture and to the fact that specific tests for thallium are not performed. As a result, these cases partly escape registration altogether and partly are wrongly diagnosed. Thallium and its compounds belong to the first class of poisons, their dangerousness being enhanced by their easy permeability through the skin. Industrial thallium poisoning can be either acute or chronic, but in all cases, it is characterized by a long duration and severity of its course. Strict hygienic demands on the organization of the technological process and the measures of protection of persons working with thallium are indispensable. Compulsory examination of the urine of those working with thallium for the presence of this substance should also be introduced.

Adult↗

Thallium poisoning: a review.

Thallium poisoning is one of the most complex and serious toxicities known to man. The symptomatology of its toxicity is usually nonspecific due to the multi-organ involvement. The initial symptoms of thallium poisoning may include fever, gastrointestinal problems, delirium, convulsions and coma. Symptoms may appear rapidly, but more commonly the acute toxicity subsides to be replaced by a gradual development of mild gastrointestinal disturbances, polyneuritis, encephalopathy, tachycardia, skin eruptions, stomatitis, atrophic changes of the skin, nail changes (Mee's lines), and skin hyperesthesia (mainly in the soles of the feet and the tibia). Degenerative changes of the heart, liver and kidney, subarchanoid hemorrhage, bone marrow depression, and increased radiopacity of the liver may also occur. Development of psychotic behavior with hallucinations and dementia has also been reported. In humans the most characteristic sign of thallium toxicity is alopecia which usually appears in cases when death is delayed for 15-20 days. Other signs and symptoms may develop at any stage of toxicity. The current therapy for thallium poisoning is the use of prussian blue and potassium chloride. Potassium therapy is probably the single most effective agent in the treatment of thallium poisoning. Further research, however, is needed to find an optimal antidote for thallium.

Animals↗

[Correlation between myocardial Thallium-201 kinetics, myocardial lactate metabolism and coronary angiographic findings in hypertrophic cardiomyopathy (author's transl)].

In 20 patients with idiopathic hypertrophic obstructive and nonobstructive cardiomyopathy (IHSS), biphasic Thallium-201 myocardial scintigraphy was performed. Regional myocardial Thallium-201 kinetics of these patients were analysed by a semiquantitative computerized method and compared with those of 6 normal subjects. In 12 of 18 with IHSS and no coronary artery disease 26 regions of interest with irreversible and 6 regions of interest with reversible Thallium-201 defects could be detected. Most of the Thallium-201 defects were localized in the interventricular septum. The defects were not related to the age of the patients and there was no relationship between the occurrence of reversible Thallium-201 defects and pathological myocardial lactate extraction rate during maximal atrial pacing measured in 14 patients. The percentage (6.8%) of irreversible defect regions in patients with LV outflow obstruction at rest (n = 13) was more than twice higher compared to those (n = 5, 3.2%) without LV outflow obstruction or no provocative pressure gradient, resp. These data suggest that IHSS is often associated with regional ischemic myocardial fibrosis despite normal coronary arteries. Therefore in these patients Thallium scintigraphy cannot be used as a noninvasive screening method to exclude or prove coronary artery disease.

Adult↗