PubMed Health⌕ Search

Biomedical subjects

L Pace

Publications and source records attributed to L Pace.

At least 109 records · Page 6Linked to original sources
PubMed1988

[The use of single-photon emission computed tomography in cardiology].

The tomographic distribution of thallium 201 in the myocardium was studied with a gamma camera with 2 detectors (29 cms in diameter) with 37 photo multipliers each. The camera was connected to a PDP computer with a 256 Kbytes memory. Thallium 201 in a dose of about 74 MBq 2 mCi was used in normal subjects, patients with coronary artery disease and with cardiac hypertrophy. Tomographic sections were obtained every 1.2 cms in the sagittal and frontal projections. The distribution of the Thallium was uniform in normal and hypertrophic hearts. Focal defects were seen in C.A.D. Single-photon emission computerized tomography was instrumental in determining the extension of the damage of the myocardium to areas which appeared normal in the regular thallium 201 scintigrams.

Cardiomyopathies↗
PubMed1987

Effects of intravenous verapamil administration on left ventricular diastolic function in systemic hypertension.

The effects of intravenous verapamil administration (0.1 mg/kg as a bolus followed by an infusion of 0.007 mg/kg/min) were studied using high-temporal-resolution radionuclide angiography in 27 patients with hypertension. Verapamil administration increased heart rate from 69 +/- 11 to 75 +/- 12 beats/min (p less than 0.001) and decreased systolic, diastolic and mean blood pressures (BPs) from 155 +/- 21/102 +/- 12 mm Hg (mean 119 +/- 14) to 142 +/- 19/95 +/- 12 mm Hg (mean 109 +/- 13) (p less than 0.001 for all). Ejection fraction decreased significantly (from 65 +/- 10% to 60 +/- 11%, p less than 0.005); peak filling rate, however, increased significantly only in patients in whom it was subnormal in the basal study (from 2.2 +/- 0.4 to 3.0 +/- 0.6 end-diastolic counts/s, p less than 0.001). These latter patients had significantly higher values of left ventricular (LV) mass index than patients with normal or increased peak filling rate (129 +/- 22 vs 112 +/- 22 g/m2, respectively, p less than 0.05). The isovolumic relaxation period changes were inversely related to the baseline values (r = 0.83, p less than 0.001). In the subgroup of patients in whom isovolumic relaxation period lengthened, time to end systole decreased (from 360 +/- 31 to 329 +/- 30 ms, p less than 0.025) and time to onset of rapid filling increased (from 420 +/- 31 to 451 +/- 34 ms, p less than 0.025), whereas these 2 intervals had opposite patterns in patients in whom isovolumic relaxation period decreased or did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

[Involvement and function of the right ventricle in acute myocardial infarct. Hemodynamic, echocardiographic and angioscintigraphic correlations].

To assess the acute effects of myocardial infarction on right ventricular function 22 patients were studied utilizing right heart catheterization, radionuclide angiography and two dimensional echocardiography. Thirteen patients had inferior myocardial infarction (Group I) and 9 anteroseptal or anterior (Group II). Hemodynamic findings suggesting right ventricular infarction were present in 3 patients of Group I. Mean radionuclide right ventricular ejection fraction was lower in inferior myocardial patients (38.2 +/- 7.6-Group I vs 50.3 +/- 11.4-Group II, p less than 0.005), while left ventricular ejection fraction in anteroseptal, and anterior myocardial infarction patients (36.8 +/- 10.5-Group II vs 55.9 +/- 7.6-Group I, p less than 0.001). Six patients in Group I presented a depressed radionuclide right ventricular ejection fraction (less than 40%): moreover right ventricular ejection fraction correlated with left ventricular ejection fraction in Group II (r = 0.79, p less than 0.001) but not in Group I (r = 0.55, p = NS). By mean of 2 dimensional echocardiography Group I patients had an increased right ventricular end diastolic area (15.3 +/- 3.8 vs 12.1 +/- 1.2 cm2, p less than 0.05) while Group II an increased right ventricular free wall motion (47.3 +/- 10.7 vs 32.4 +/- 14.1%, p less than 0.005); right ventricular end diastolic area correlated with right ventricular ejection fraction only in Group I (r = 0.60, p less than 0.05). Five patients in Group I and no patients in Group II had an enlarged right ventricular end diastolic area. Therefore, radionuclide and echocardiographic evidence of right ventricular involvement were not always associated with abnormal hemodynamics. Thus, the damaged right ventricular chamber dilates to allow an adequate stroke volume in presence of low ejection fraction; hemodynamic significant right ventricular myocardial infarction becomes evident only in patients with more severe right ventricular compromise; the increase in right ventricular free wall motion in anterior myocardial infarction patients compensates the loss of contribution of interventricular septum contraction.

Adult↗
PubMed1984

Effect of beta-blockade on thallium-201 dipyridamole myocardial scintigraphy.

The effect of beta-blockade on dipyridamole thallium-201 images was assessed in 8 patients with coronary artery disease and positive dipyridamole test. Three dipyridamole thallium-201 tests were performed, the first in basal conditions, the second 30' after propranolol and the third with propranolol and atrial pacing. After dipyridamole heart rate and double product increased respectively from 75 +/- 7 to 98 +/- 15 b/min (p less than 0.01 vs starting values) and from 10 551 +/- 1255 to 11 740 +/- 4542 mmHg X b/min (p less than 0.05 vs starting values). Propranolol reduced heart rate to 64 +/- 6 b/min (p less than 0.05 vs basal conditions), systolic blood pressure to 136 +/- 13 and double product to 8733 +/- 1248 (p less than 0.05 vs basal conditions). Dipyridamole when infused after propranolol, induced an increase in heart rate to 70 +/- 5 b/min (p less than 0.05 vs starting values) while double product was 9133 +/- 1189 mmHg X b/min (p = NS vs starting values). Atrial pacing prevented the fall in heart rate and double product induced by propranolol so during dipyridamole infusion double product increased to 13 271 +/- 1868 (p less than 0.05 vs propranolol treatment; p less than 0.05 vs starting values). Segmental score calculated after dipyridamole was 5.2 +/- 2.0 in basal conditions, 5.1 +/- 1.3 after propranolol (p = NS) and 4.8 +/- 1.3 after propranolol plus atrial pacing (p = NS). Thus the results of the study show that beta-blockade does not worsen dipyridamole thallium-201 images. Furthermore the steal phenomenon seems to be the main mechanism of the dipyridamole induced ischemia. In fact, also when the increase, oxygen consumption is blunted with beta-blockade the disparity in myocardial blood flow resulted unaffected.

Blood Pressure↗
PubMed1984

[Comparative evaluation of saccoradiculography and lumbar phlebography in the diagnosis of lumbar disk herniation].

A comparative evaluation of two relevant methods (saccoradiculography and lumbar epidural venography), based on 246 case studies (133 of which surgically treated), did not reveal that one of the two could be adopted as elective test with regard to its diagnostic accuracy. However if we consider tolerance and complications of each method, lumbar epidural venography appears to be the elective test in herniated lumbar disk diagnosing.

Diagnosis, Differential↗
PubMed1984

Effect of procetofen on serum lipids and apoproteins.

The effect of procetofen (fenofibrate) on lipids and apoproteins was studied in ten patients affected with familial type II-A and II-B hyperlipoproteinemia. Following stabilization with an isocaloric diet for 2 months, the patients were given 300 mg/day of procetofen for 3 months, then placebo for 1 month. Plasma cholesterol and triglycerides were decreased by 15% and 46%, respectively. Plasma apo B was lowered by 17%. The predominant decrease in lipids and apoproteins occurred in VLDL, whereas in HDL cholesterol increased significantly but not its major apoprotein, apo A-I. A mechanism of action involving increased catabolism of VLDL and reduced synthesis of LDL and VLDL is proposed.

Adult↗
PubMedDate not supplied

Risk stratification of patients with coronary artery disease and left ventricular dysfunction by exercise radionuclide angiography and exercise electrocardiography.

BACKGROUND: The results of multicenter trials indicate that patients with left ventricular dysfunction and either three-vessel or left main coronary artery disease have improved prognosis when treated surgically. OBJECTIVE: As part of a larger evaluation and follow-up study of coronary artery disease, the objective of this investigation was to determine whether exercise radionuclide angiography can be used, in patients with mild symptoms of coronary artery disease and left ventricular dysfunction at rest, to identify patients with three-vessel or left main coronary artery disease. METHODS AND RESULTS: Eighty-four consecutive patients were studied with angiographically defined coronary artery disease in whom left ventricular ejection fraction at rest ranged from 20% to 40%. Patients underwent exercise electrocardiography, rest and exercise radionuclide angiography, and 24-hour electrocardiographic monitoring. There were 22 patients with one-vessel, 31 with two-vessel, 27 with three-vessel, and four with left main coronary artery disease. All but four patients had a documented history of myocardial infarction. By univariate analysis, the following parameters were related to the anatomic severity of coronary artery disease: magnitude of ST segment depression with exercise (p < 0.001), magnitude of change in ejection fraction with exercise (p < 0.005), and occurrence of angina during exercise (p < 0.005). However, because of the extensive overlap among anatomic subgroups, no single factor had both a satisfactory sensitivity and a satisfactory specificity in identifying patients with three-vessel and left main coronary artery disease. Multivariate stepwise regression analysis also failed to predict three-vessel or left main coronary artery disease satisfactorily (sensitivity 73% and specificity 73%; positive predictive accuracy 59% and negative predictive accuracy 83%). Nonetheless, this multivariate analysis provided important prognostic information. During medical therapy (mean follow-up 56 months), the patients with a high likelihood of three-vessel or left main coronary artery disease had a greater risk of death or reinfarction than had patients with a low likelihood (p < 0.05). These functional data were better than coronary anatomy alone in providing risk stratification. Four of six patients with two-vessel disease who died were classified incorrectly by the multivariate analysis in the high-likelihood group for three-vessel or left main coronary artery disease, but classified correctly as being at high risk; whereas none of the patients with three-vessel disease who were misclassified in the low-likelihood group died during medical therapy. CONCLUSION: Although exercise radionuclide angiography in patients with minimal symptoms of coronary artery disease and left ventricular dysfunction is not precise in predicting three-vessel or left main coronary artery disease, it provides important functional information regarding subsequent prognosis during medical therapy.

Adult↗
PubMedDate not supplied

Left ventricular dysfunction in coronary artery disease: comparison between rest-redistribution thallium 201 and resting technetium 99m methoxyisobutyl isonitrile cardiac imaging.

BACKGROUND: We compared rest-redistribution thallium 201 and resting technetium 99m methoxyisobutyl isonitrile (MIBI) cardiac imaging in 29 men with angiographically proven coronary artery disease and regional ventricular dysfunction. Left ventricular ejection fraction at radionuclide angiography was 35% +/- 9%. METHODS AND RESULTS: Regional left ventricular wall motion was assessed on gated 99mTc MIBI images according to a 3-point scale (0 = normal, 1 = hypokinetic, 2 = akinetic or dyskinetic). 201Tl and 99mTc MIBI uptake values were analyzed quantitatively. A total of 435 myocardial segments were classified on the basis of wall motion analysis into three groups: group 1 (normal wall motion; n = 201), group 2 (hypokinetic; n = 132), and group 3 (akinetic or dyskinetic; n = 102). 201Tl and 99mTc MIBI uptake values were significantly higher in groups 1 and 2 compared with group 3 (p < 0.05) and in group 1 compared with group 2 (p < 0.05). When 201Tl and 99mTc MIBI uptake values were directly compared, no significant differences in group 1 and 2 were observed. In group 3, 99mTc MIBI uptake (67% +/- 14%) was significantly lower (p < 0.001) than initial (72% +/- 11%) and delayed 201Tl uptake (73% +/- 12%). CONCLUSION: Thus rest-redistribution 201Tl and resting 99mTc MIBI cardiac imaging reflect the severity of left ventricular dysfunction in coronary artery disease. However, in segments with severely impaired regional ventricular function, 201Tl uptake is significantly higher than 99mTc MIBI uptake.

Adult↗
PubMedDate not supplied

Adenosine coronary vasodilation quantitative technetium 99m methoxy isobutyl isonitrile myocardial tomography in the identification and localization of coronary artery disease.

BACKGROUND: Exercise and dipyridamole 99mTc-labeled methoxy isobutyl isonitrile (MIBI) myocardial scintigraphy have been widely used for the diagnosis of coronary artery disease (CAD). However, only limited data on adenosine 99mTc-labeled MIBI cardiac imaging are currently available. This study was designed to assess the accuracy of quantitative adenosine-rest 99mTc-labeled MIBI tomography in the diagnosis and localization of CAD. METHODS AND RESULTS: Fifty-seven consecutive patients with suspected CAD who underwent coronary angiography and 22 normal volunteers were studied. All patients underwent 99mTc-labeled MIBI tomography after administration of adenosine (140 micrograms/kg intravenously for 6 minutes) and at rest. A total of 171 vascular coronary territories were analyzed quantitatively. All patients with CAD (> or = 50% luminal stenosis) (n = 55) had abnormal 99mTc-labeled MIBI tomograms. The normalcy rate was 86% by quantitative analysis. Overall sensitivity, specificity, and diagnostic accuracy for detection of individual stenosed vessels were 84%, 87%, and 85%, respectively. In patients with one-vessel CAD (n = 24), sensitivity and diagnostic accuracy in the detection of individual stenosed vessels were significantly (p < 0.05) higher compared with patients with multivessel CAD (n = 31). Moreover, 75% of patients with one-vessel disease showed a scintigraphic pattern characterized by the presence of perfusion defects in only one coronary artery territory, and 74% of patients with multivessel disease showed a scintigraphic pattern characterized by the presence of perfusion defects in two or more coronary artery territories. Sensitivity, specificity, and diagnostic accuracy for detecting individual diseased vessels were similar in patients without previous myocardial infarction (n = 18) compared with those with previous myocardial infarction (n = 39). In myocardial territories related to noninfarcted areas (n = 124), sensitivity and specificity in the detection of stenosed vessels were 75% and 88%. In infarcted areas (n = 47), sensitivity and specificity in the detection of stenosed vessels were 98% and 80% (differences not significant vs noninfarcted areas). CONCLUSIONS: Adenosine-controlled coronary vasodilation combined with quantitative 99mTc-labeled MIBI tomography is accurate for identifying patients with CAD and localizing individual stenosed coronary arteries.

Adenosine↗
PubMedDate not supplied

Technetium 99m-labeled tetrofosmin myocardial tomography in patients with coronary artery disease: comparison between adenosine and dynamic exercise stress testing.

BACKGROUND: Pharmacologic coronary vasodilation with adenosine, combined with myocardial scintigraphy, is a useful test for the diagnosis of coronary artery disease (CAD) in patients unable to exercise. It has been demonstrated recently that exercise 99mTc-labeled tetrofosmin cardiac imaging can be used for the detection of CAD. However, no data are available comparing 99mTc-labeled tetrofosmin adenosine and exercise tests in the same patients. METHODS AND RESULTS: The results of adenosine and exercise 99mTc-labeled tetrofosmin myocardial tomography were compared in 41 patients (37 men and four women; mean age 53 +/- 8 years) with suspected or known CAD who underwent coronary angiography. All patients were submitted, on separate days, to three injections of 99mTc-labeled tetrofosmin (740 MBq intravenously): one at rest, one during bicycle exercise, and one during adenosine infusion (140 micrograms/kg/min for 6 minutes with injection of 99mTc-labeled tetrofosmin at 4 minutes). A total of 902 myocardial segments were analyzed quantitatively. One patient had normal coronary vessels, 19 patients had single-vessel CAD, 12 patients had two-vessel CAD, and nine patients had three-vessel CAD (> 50% coronary stenosis) on coronary angiography. Adenosine induced a significant increase in heart rate (88 +/- 16 beats/min at peak vs 72 +/- 11 beats/min at rest; p < 0.01). Systolic and diastolic blood pressure was not significantly different after adenosine infusion compared with rest. Double product was 22931 +/- 7039 at peak exercise and 11229 +/- 3413 after adenosine (p < 0.01). Agreement on the presence of abnormal single-photon emission computed tomography by adenosine and exercise was 100% by quantitative analysis. In all segments a significant relationship between exercise and adenosine 99mTc-99m-labeled tetrofosmin uptake was observed (r = 0.90; p < 0.001). Segmental agreement for regional 99mTc-labeled tetrofosmin uptake score between exercise and adenosine was observed in 737 (82%) of the 902 segments (kappa value of 0.66). Concordance between the two studies for identification of perfusion status was observed in 809 (90%) of the segments (kappa value of 0.80). Sensitivity and specificity for detection of stenosed vessels were not different for dynamic exercise stress testing and adenosine 99mTc-labeled tetrofosmin cardiac tomography. CONCLUSIONS: Despite different hemodynamic effects, adenosine and dynamic exercise 99mTc-labeled tetrofosmin single-photon emission computed tomographic imaging provides similar information in the diagnosis and localization of CAD.

Adenosine↗
PubMedDate not supplied

Direct comparison of technetium 99m-sestamibi and technetium 99m-tetrofosmin cardiac single photon emission computed tomography in patients with coronary artery disease.

BACKGROUND: Technetium 99m-labeled sestamibi and tetrofosmin tomography have shown high diagnostic accuracy in the detection of coronary artery disease (CAD). However, few data are available comparing sestamibi and tetrofosmin imaging in the same patients. The aim of the study was to determine the image quality of the two tracers and to compare the results of exercise sestamibi and tetrofosmin tomography in the same patients. METHODS: The results of exercise-rest sestamibi and tetrofosmin myocardial tomography were compared in 32 patients with suspected or known CAD who underwent coronary angiography. Image quality was evaluated subjectively. Regional tracer distribution was visually assessed and quantitatively measured in 22 segments/patient. RESULTS: At coronary angiography, 7 patients had normal coronary vessels, 11 single-vessel, and 14 multivessel CAD (> or =50% luminal stenosis). Image quality judged visually was comparable with the two tracers. Heart/lung and heart/liver ratios for sestamibi and tetrofosmin were not different. At visual analysis, 68% of the patients with CAD had abnormal findings with sestamibi and 76% with tetrofosmin (p = NS). At quantitative analysis, 92% of the patients with CAD had abnormal findings with sestamibi and 96% with tetrofosmin (p = NS). At both visual and quantitative analyses, sensitivity, specificity, and diagnostic accuracy in the detection of individual stenosed vessels were not different between the two tracers. Moreover, for both tracers sensitivity, specificity, and diagnostic accuracy in the detection of diseased vessels were significantly higher (all p < 0.05) at quantitative compared with visual analysis. Finally, defect size and severity were similar for the two tracers. CONCLUSIONS: Exercise-rest sestamibi and tetrofosmin tomography yielded images of comparable quality and provided similar results in the identification of patients with CAD and in the detection of the individual stenosed coronary vessels.

Adult↗
PubMedDate not supplied

Effects of myocardial revascularization on regional thallium-201 uptake and systolic function in regions with reverse redistribution on tomographic thallium-201 imaging at rest in patients with chronic coronary artery disease.

OBJECTIVES: There is growing evidence that myocardial segments with reverse redistribution are viable in patients with chronic coronary artery disease. The aim of this study was to assess the effects of myocardial revascularization on systolic function and thallium-201 uptake in such segments. METHODS: Rest-redistribution thallium-201 tomography before and after myocardial revascularization was performed in 47 patients with chronic coronary artery disease. Regional function was evaluated by two-dimensional echocardiography before and after revascularization according to a 3-point scale (1 = normal, 2 = hypokinetic, 3 = a/dyskinetic). Improvement of dysfunctional segments was defined when systolic function score decreased > or =1 after revascularization. Reverse redistribution was defined as >8% decrease in relative thallium-201 uptake between rest and redistribution images. RESULTS: Reverse redistribution was found in 27 (57%) of 47 patients, corresponding to 60 (11%) of 564 myocardial segments. Of such segments, 24 (40%) had normal systolic function, 19 (32%) were hypokinetic, and 17 (28%) were a/dyskinetic. Thirty-six segments underwent myocardial revascularization, and reverse redistribution was no longer present in 86% of them subsequent to the procedure. Of 26 dyssynergic segments with reverse redistribution subjected to revascularization, 18 (69%) improved at follow-up. CONCLUSIONS: The findings of the present study indicate that reverse redistribution is a reversible phenomenon and is often associated with improvement of systolic function following revascularization in patients with chronic coronary artery disease.

Aged↗
PubMedDate not supplied

Exercise-test Tc-99m tetrofosmin SPECT in patients with chronic ischemic left ventricular dysfunction: direct comparison with Ti-201 reinjection.

BACKGROUND: This study was designed to compare the results of exercise-rest technetium-99m tetrofosmin single photon emission computed tomography (SPECT) with those of thallium-201 reinjection at rest after exercise-redistribution imaging in the same patients with chronic ischemic left ventricular (LV) dysfunction. METHODS: Within 1 week, 33 patients with chronic myocardial infarction and LV dysfunction underwent exercise-rest tetrofosmin SPECT and Tl-201 reinjection at rest after exercise-redistribution imaging. In each patient, regional tetrofosmin and Tl-201 activity was quantitatively measured in 22 myocardial segments. Regional LV function was assessed in corresponding segments by echocardiography. RESULTS: Agreement in the evaluation of regional perfusion status between tetrofosmin and Tl-201 imaging was observed in 78% of the 726 total segments, with a kappa value of 0.61. In segments with normal function at echocardiography (n = 436), no difference between Tl-201 and tetrofosmin uptake was observed. In hypokinetic segments (n = 138), exercise tetrofosmin uptake was lower (P < .01) as compared with exercise Tl-201 activity, whereas no difference was observed between tetrofosmin uptake at rest as compared with Tl-201 activity on redistribution and reinjection images. In segments with severe functional impairment (akinetic or dyskinetic, n = 152), tetrofosmin uptake on exercise images was reduced (P < .01) as compared with exercise Tl-201 activity; furthermore, tetrofosmin uptake at rest was lower (P < .01) as compared with Tl-201 activity on both redistribution and reinjection images. In these segments, concordance in the detection of myocardial viability between tetrofosmin and Tl-201 imaging was observed in 138 (91%) of the 152 segments, with a kappa value of 0.77. CONCLUSIONS: In patients with chronic coronary artery disease and LV dysfunction quantitative exercise-rest tetrofosmin and Tl-201 reinjection SPECT provide similar information in the assessment of perfusion status and in the detection of myocardial viability.

Adult↗