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Biomedical subjects

F Fedele

Publications and source records attributed to F Fedele.

At least 19 recordsLinked to original sources
PubMed1992

Transesophageal dipyridamole echocardiography for diagnosis of coronary artery disease.

The value of transthoracic dipyridamole echocardiography has been extensively documented. However, in some patients, because of a poor acoustic window, the rest transthoracic examination is not always feasible and the transesophageal approach is more convenient. Therefore, transesophageal echocardiography with high dose dipyridamole (up to 0.84 mg/kg body weight over 10 min) was performed in 32 patients in whom the transthoracic dipyridamole test either was not feasible (n = 29) or yielded ambiguous results (n = 3). The transesophageal echocardiographic test results were considered abnormal when new dipyridamole-induced regional wall motion abnormalities were observed. All 32 patients underwent coronary angiography; significant coronary artery disease was defined as greater than or equal to 70% lumen diameter narrowing in at least one major vessel. All patients also performed a bicycle exercise test 1 day before transesophageal dipyridamole echocardiography. Transesophageal stress studies were completed in all patients, with a maximal imaging time (in tests with a negative result) of 20 min. No side effects or intolerance to drug or transducer was observed. The left ventricle was always visualized in the four-chamber and transgastric short-axis views. High quality two-dimensional echocardiographic images were obtained in all patients both at rest and at peak dipyridamole infusion and were digitally analyzed in a quad-screen format. Coronary angiography showed coronary artery obstruction in 24 patients: 6 had single-, 9 double- and 9 triple-vessel disease. The transesophageal dipyridamole test showed a specificity of 100% and an overall sensitivity of 92%. The sensitivity of this test for single-, double- and triple-vessel disease was 67%, 100% and 100%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Angiography↗
PubMed1992

Identification of coronary artery by-pass grafts: reliability of MRI in clinical practice.

In order to test MRI ability to detect the number and the sites of coronary artery by-pass grafts (CABGs), 22 patients with CABGs were studied. The detection of a neo-vessel in even one of the examination slices was considered as positive for the study, disregarding the difference between its origin and course. With such a criterion, MRI total percentage of vascular bridges identification resulted in 76.1% (51/67) with very low values for CABGs implanted on diagonal, obtuse marginal and posterior descending vessels (11/24 = 45.8%). These results lead to the conclusion that, although MRI has some advantages in the identification of CABGs implanted on the main coronary vessels in the early post-operative period, its extensive use cannot be proposed at the present state of the art.

Adult↗
PubMed1992

Endogenous opioid system modulation in anginal pain: demonstration of its central activity.

Plasma beta-endorphin levels provide controversial results on the role of endogenous opioid system in modulation of anginal pain. As an alternative, the action of plasmatic luteinizing hormone after administration of naloxone was investigated: naloxone blocks the tonic endogenous opioid system inhibition of gonadotropin release; thus, the level of luteinizing hormone after naloxone administration is an index of central endogenous opioid system activity. Twenty patients with coronary artery disease and positive results of stress tests were selected: 10 had angina (group I) and 10 did not (group II). Ten healthy subjects were also studied as a control group (group III). In all patients basal plasma beta-endorphin levels, basal luteinizing hormone plasma levels (every 15 minutes for 1 hour) and luteinizing hormone plasma levels after administration of 0.1 mg/kg naloxone over 4 minutes (every 15 minutes for 2 hours) were determined. In 15 patients the test was performed after luteinizing hormone releasing hormone was given. The integral concentration time of luteinizing hormone plasma level during baseline (LHiB) and after administration of naloxone (LHiN) or luteinizing hormone releasing hormone (LHiRH), the ratio (LHiN:LHiB and LHiRH:LHiB) and the differences (LHiN-LHiB and LHiRH-LHiB) between the postinfusion period and baseline were calculated. No difference was found in beta-endorphin plasma levels and luteinizing hormone response after luteinizing hormone releasing hormone infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

[Early isovolumetric relaxation: correlation with the densitometric analysis of coronary stenosis].

Early relaxation is characterized by a segmental outward wall movement during isovolumic relaxation. There is still no general agreement as to its significance. Some Authors have considered the phenomenon to be a specific marker of isolated coronary narrowing, others have regarded it as a normal variation of left ventricular relaxation and still others concluded that it is a compensatory phenomenon to local ischemia in another region. We used a method of quantitative assessment of regional left ventricular function and a videodensitometric analysis of coronary stenosis. In our study we didn't observe an improved systolic function of the regions that presented early relaxation, but a slight non significant reduction. We did neither observe any correlation between early relaxation and ischemia provoked by stress test nor between early relaxation and coronary artery disease. The amplitude of early relaxation was not statistically different between patients with and without stenosis of left anterior descending artery. We conclude that early relaxation is a normal variation of left ventricular relaxation.

Constriction, Pathologic↗
PubMed1991

Assessment of severity of coronary narrowings by quantitative exercise echocardiography and comparison with quantitative arteriography.

To determine the correlation of quantitative assessment of coronary narrowings with left ventricular functional impairment induced by exercise, 57 patients with 1-vessel coronary artery disease and without evidence of collateral flow were studied. A significant relation was observed between minimal cross-sectional area, percent area stenosis, minimal lumen diameter, percent diameter stenosis and the percentage of segmental area change from rest to peak exercise in a vascular distribution territory (r = 0.76, p less than 0.001; r = -0.55, p less than 0.001; r = 0.56, p less than 0.001; r = -0.75, p less than 0.001, respectively). For minimal cross-sectional area, the best cut-off value to separate significantly patients who had a decrease in contractility at peak exercise testing from those who had a normal response was 2 mm2 (p less than 0.001); for percent cross-sectional area stenosis, it was 75% (p less than 0.001); for minimal lumen diameter, it was 0.7 mm (p less than 0.001); and, for percent diameter stenosis, it was 85% (p less than 0.001). High cut-off values for angiographic variables are necessary to separate significantly patients who have a decrease in contractility at peak exercise testing from those who have a normal response. Several patients with mild coronary stenoses may have either normal or abnormal wall motion during exercise. Thus, exercise echocardiography is a useful tool in detecting the presence of fairly severe anatomic narrowing, whereas it is of limited clinical use in the assessment of intermediate coronary atherosclerotic lesions.

Cineangiography↗
PubMed1991

[Noninvasive determination of anaerobic threshold: validation of an automatic computerized method].

The Authors propose a computerized method in order to automatically detect the anaerobic threshold by the analysis of ventilatory parameters (VE, VO2). The algorithm calculates all possible linear fits and the relative standard error of the relationship between VE and VO2 beginning from the first set of 4 data (excluding the first 2 min of exercise) and increasing of 1 pair of data until peak exercise. Subsequently the program chooses the line that fits the greatest number of data with the smallest error. The ventilatory anaerobic threshold (SA Ve) is then calculated as the point at which the relationship between VE and VO2 is no more linear (i.e. when the VE measured gets over of 2 standard errors the calculated value on the basis of the regression formula). During the first phase of the study the method was validated against invasive AT determination by arterial lactate concentration (SA La) in 14 patients (7 athletes, 7 healthy sedentary subjects) during a symptom-limited ergospirometric test (in supine position, 10 W/min until exhaustion). Subsequently we studied the method repeatability in 20 men (10 normals, 10 patients with congestive heart failure who performed 2 ergospirometric tests on separate days. The results showed a good correlation when comparing each other the VO2 (SA Ve 26.88 +/- 4.24, SA La 25.95 +/- 3.88 ml/kg/min; r = 0.88) or the onset time (SA Ve 11.8 +/- 2.42, SA La 11.61 +/- 1.8 min; r = 0.91) of anaerobic threshold determined by the 2 methods.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Role of endogenous opioids on nociceptive threshold in patients with exercise-induced myocardial ischemia.

To evaluate whether endogenous opioids (EO) play a role in the perception of anginal pain, a randomized double blind clinical trial, using naloxone (N) and placebo (P) and measuring beta-endorphin (beta-ep) plasma levels, was performed. We studied 10 patients with angiographically assessed coronary artery disease (CAD) and stable exercise-induced myocardial ischemia (established by 2 preliminary bicycle ergometric tests) of whom 5 symptomatic (SYM) and 5 asymptomatic (ASYM) and 5 subjects without CAD as a control group (CON). On a third exercise test the beta-ep plasma level (fmol/ml) was measured at rest (SYM 5.4 +/- 2.3 vs ASYM 7.2 +/- 2.3 vs CON 6.8 +/- 2.6, NS), at peak exercise (SYM 4.4 +/- 1.8 vs ASYM 8.0 +/- 4.2 and vs CON 6.2 +/- 2.7, NS) and during recovery (SYM 7.5 +/- 4.2 vs ASYM 7.2 +/- 3.0 vs CON 6.7 +/- 2.5, NS). On 2 subsequent tests patients received N (0.2 mg/kg) or P intravenously and chest pain was evaluated on an analogue scale (score from 1 to 10). After N compared to P we observed: an increased perception of chest pain in SYM (6.8 +/- 1.5 vs 4.2 +/- 1.0; p less than 0.01) without significant changes of the ischemic threshold (total work, heart rate-blood pressure product, ST segment changes, 2D-echocardiographic wall motion abnormalities); no modifications in ASYM and CON.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Usefulness of the dipyridamole-Doppler test for diagnosis of coronary artery disease.

Two-dimensional and Doppler echocardiographic studies and a hemodynamic investigation were performed during dipyridamole testing in 42 subjects (13 control subjects and 29 patients with coronary artery disease [CAD]), to evaluate the ability of dipyridamole Doppler echocardiography in identifying patients with ischemic left ventricular dysfunction. In the control group, after dipyridamole infusion, Doppler-derived parameters increased significantly from baseline (p less than 0.001). In patients with CAD, peak flow velocity, flow velocity integral and stroke volume failed to increase after dipyridamole infusion (0.89 +/- 0.21 to 0.85 +/- 0.18 m/s, difference not significant; 14 +/- 3 to 12 +/- 4 cm, difference not significant, and 56 +/- 13 to 50 +/- 14 ml/beat, p less than 0.05, respectively). Heart rate, rate pressure product, systemic vascular resistance and mean right atrial pressure had similar variations in the 2 groups. Changes in the 3 Doppler-derived parameters are closely related to the variations of peak positive dP/dt, stroke volume (thermodilution) and left ventricular end-diastolic pressure and are closely related to the coronary angiography jeopardy score and to the appearance of wall motion abnormalities. Thus, by combining Doppler and 2-dimensional echocardiography, dipyridamole-induced myocardial ischemia may be detected in a high percentage of CAD patients, providing a sensitive tool for identifying patients with high-risk coronary artery anatomy.

Adult↗
PubMed1990

Physiologic role of coronary PGI2 and PGE2 in modulating coronary vascular response to sympathetic stimulation.

To investigate a physiologic role of coronary prostacyclin (PGI2) and prostaglandin E2 (PGE2) 30 patients who were not affected by coronary heart disease were evaluated for coronary hemodynamics and coronary PGI2 and PGE2 production. Inhibition of coronary prostaglandin biosynthesis by ketoprofen (1 mg/kg) or aspirin (15 mg/kg) administered intravenously did not significantly change coronary hemodynamics in resting conditions. In all patients cold pressor tests induced significant increases in coronary blood flow (p less than 0.001) and decreases in coronary vascular resistance (p less than 0.001) without changes in cardiac oxygen extraction and with consequent increases in calculated myocardial oxygen consumption. Simultaneously, a marked increase in coronary PGI2 (as 6-keto-PGF1 alpha) and PGE2 formation was observed (p less than 0.001). Both ketoprofen (1 mg/kg) and aspirin (15 mg/kg) administration completely abolished PGI2 and PGE2 formation that was induced by cold pressor test and caused a paradoxical increase in coronary vascular resistance (ketoprofen: p less than 0.02; aspirin: p less than 0.05). The results of this study support a physiologic role for the coronary prostaglandins in modulating coronary vascular response to sympathetic stimulation in nonischemic patients.

Adult↗
PubMed1990

[Effect of changes of the left ventricular diastolic pressure on the coronary circulation hemodynamics].

In order to understand the effect of LVEDP changes caused by contrast injection during angiography on coronary hemodynamics we studied 15 patients (5 congestive CMP, 5 mixed angina and 5 controls). Our results do not cope with an important negative role played from LVEDP changes on coronary hemodynamics and cardiac metabolism. Actually LVEDP increase after ventriculography was balanced by coronary flow increase and impedance reduction even when the latter has been matched with LVEDP. We also observed lactate metabolism changes which are not likely to be provoked by myocardial ischemia, since there was not a definite negativization of % lactate extraction and delta A-VO2 always turned to reduction; this is apparently not in agreement with other Authors who had reported metabolic alterations suggestive for myocardial ischemia, even if they did not calculate delta A-VO2 and coronary flow. This difference could be related to the different populations studied, specially when considering the different functional meaning of coronary stenoses of the same degree at angiography. Is thus the Authors' thought that, when coronary reserve is still adequate, is it possible not to take into account LVEDP, which becomes important in patients with a more advanced coronary disease as in those cases this extravascular impedance factor to coronary flow could take his own worsening role.

Adult↗
PubMed1990

[Stratification of risk in infarcts without Q wave: role of echocardiography at rest and during exertion].

To assess the relation between the extent of myocardial necrosis and the presence of myocardium at risk in myocardial infarction without Q waves (NQMI) we studied by echocardiography the prevalence of jeopardized myocardium in a group of NQMI stratified on the basis of left ventricular wall motion (akinesis, hypokinesis, normal kinesis). We have studied 60 consecutive patients with non-Q myocardial infarction. Patients were examined by 2D echo at rest (V-VI day from the acute episode) and during symptoms limited bicycle ergometric test (ExT) (XX-XXX day). Regional left ventricular wall motion was evaluated as normal or asynergic (severe hypokinetic, akinetic) and the ExT was considered positive in case of new asynergic areas or ECG criteria. 2D echo at rest was technically satisfactory in 56 patients, 19 showed almost an akinetic segment (Aci) 17 had hypokinetic areas (Ipo) and 20 had normal left ventricle kinesis (Norc). Wall motion abnormalities were localized more frequently in the apex and lateral areas. During exercise 2D echo was performed in 46 patients (82%) with 23 positive tests (50%). Stratifying the population on the basis of left ventricle wall motion we observed a major number of positive tests in the group of patients with normal wall motion in comparison with those with asynergic areas at rest (Norc 66.6%, Ipo 35.7%, Aci 42.6% p less than 0.05 Nore vs Ipo and Nore vs Aci) despite the same CAD extension. These data show the heterogeneity of the NQMI that likely includes patients with transmural (asynergy group) and subendocardial MI (normal kinesis group), the latter with a higher degree of myocardium at risk.

Adult↗
PubMed1989

Painless versus painful myocardial ischemia: different left ventricular dysfunction detected by echocardiography.

The mechanism responsible for the absence of anginal pain in patients who have episodes of both painless and painful myocardial ischemia, still remains unknown. Does the pain depend on an overstimulation of receptive structures or is this symptom the product of the excitation of a well-defined receptive system? The aim of this work is to test the first hypothesis: whether silent attacks are accompanied by the same degree of mechanical impairment as symptomatic ones. The authors compared the echocardiographic left ventricular functional behavior in the same patient (6 patients) during painful and painless myocardial ischemia. The echocardiographic changes observed during silent ischemic attacks were significantly different from those detected during symptomatic attacks. The latter were characterized by a larger extension of the ischemic myocardium and, as a consequence, by a larger functional impairment. Symptomatic and asymptomatic ischemic attacks were recorded echocardiographically in the same patient during repeated attacks on the same day, and were always clearly differentiated by the degree of wall motion abnormalities. The echocardiographic monitoring during the ischemic attack seemed to confirm that the greater functional impairment preceded the onset of pain leading to the occurrence of this symptom. Nevertheless, it was impossible to identify a threshold value above which the ischemic attack will be symptomatic. Our data seem to indicate a close relationship between painful ischemia and a higher degree of ischemic damage. Thus, in patients with predominantly painful myocardial ischemia, the extension and the severity of ischemia could play an important role in determining this symptom.

Adult↗
PubMed1989

Tissue acidosis: role in sustained arteriolar dilatation distal to a coronary stenosis.

This study tested the hypothesis that myocardial tissue acidosis is responsible for maintenance of reduced arteriolar tone distal to a severe coronary arterial stenosis. Domestic swine (n = 10) were instrumented with a coronary arterial stenosis that reduced vessel diameter 80%. Measurements of hemodynamic indexes were made 1) before stenosis, 2) at 5, 20, and 60 minutes after stenosis placement, and 3) after each of three, 20-minute NaOH infusions (0.05 M, 0.1 M, and 0.5 M) distal to the stenosis (group 1). Intracellular pH at the end of 30 minutes of 0.5 M NaOH infusion distal to the stenosis was measured in a second group (n = 6) of swine (group 2). After stenosis placement in group 1, endocardial blood flow declined significantly, and evidence of regional acidosis (increased coronary venous Pco2 and decreased coronary venous pH) and ischemia (lactate production) developed. One hour later, evidence of acidosis persisted, though to a lesser extent. Myocardial oxygen and lactate metabolism exhibited similar patterns. Infusion of 0.5 M NaOH (0.38 ml/min) reduced (p less than 0.01) distal zone epicardial blood flow but did not change endocardial flow. Regional myocardial oxygen extraction (75 +/- 8%, mean +/- SD) and consumption (8.2 +/- 2.3 ml/min/100 g) also declined significantly (p less than 0.01) in response to 0.5 M NaOH infusion compared with 60 minutes after stenosis (86 +/- 4 and 12.4 +/- 2.8 ml/min/100 g respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗
PubMed1987

Left ventricular filling pattern in hypertensive patients after reversal of myocardial hypertrophy.

After treatment with alpha-methyldopa a regression of left ventricular hypertrophy, due to hypertension, has been reported in spontaneously hypertensive rats. The reduction of left ventricular mass has been associated with an increase in hydroxyproline concentration, suggesting secondary functional changes. On this basis, 12 patients with essential hypertension and echocardiographic evidence of left ventricular hypertrophy have been studied before and after a 6-month alpha-methyldopa treatment. Ten normal subjects were used as a control group. Curves of changes in left ventricular diameter and velocity curves were obtained by digitation of the M-mode endocardial echoes and the diastolic patterns were studied. Before treatment all patients, as compared to normal subjects, showed: (a) prolongation of the isovolumetric relaxation time index, with increased diameter changes; (b) reduction of diameter changes and peak velocity during the rapid filling; and (c) marked compensatory increase of diameter changes and peak velocity of the filling due to atrial systole. Left ventricular hypertrophy was reduced in 5 patients (first group) after treatment. This group showed: (a) normalization of the isovolumetric relaxation time index; (b) slight increase of diameter changes during rapid filling; (c) increased peak velocity of the rapid filling; and (d) reduction of diameter changes and peak velocity during atrial systole. No changes of functional data were observed in the other 7 patients (second group) in whom left ventricular hypertrophy was unchanged after treatment. It is shown how the reduction of left ventricular hypertrophy, per se, could induce such an improvement of diastolic function, despite the biochemical changes probably caused by administration of alpha-methyldopa.

Blood Pressure↗
PubMed1987

Coagulation contact phase factors and inhibitors in beta-thalassemia major children.

Selected hemostatic parameters of 23 children affected by beta-thalassemia major were studied and compared to an age- and sex-matched group. Plasma prekallikrein level was reduced in all patients, splenectomized or not. In splenectomized patients, platelet count and in vitro platelet aggregability were significantly increased and Protein C was slightly increased. The activated partial thromboplastin time was prolonged and the normotest reduced. Finally, a reduction in the plasma levels of fibrinogen and of vitamin K-dependent proteins, including the antithrombotic Protein C, was observed in nonsplenectomized patients. Our data indicate that the hemostatic system in patients with thalassemia major may be altered. The relationship between these laboratory changes and clinical manifestations remains to be established.

Adolescent↗