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Biomedical subjects

M Masini

Publications and source records attributed to M Masini.

70 records · Page 4Linked to original sources
PubMed1986

Transient myocardial dysfunction during pharmacologic vasodilation as an index of reduced coronary reserve: a coronary hemodynamic and echocardiographic study.

Regional coronary flow reserve and regional myocardial contractility were evaluated in 29 patients after maximal pharmacologic coronary vasodilation (intravenous dipyridamole, 0.56 mg/kg body weight, administered over 4 minutes). Nineteen patients had a severe (80 to 99%) proximal and isolated stenosis of the left anterior descending coronary artery and 10 patients had normal coronary arteries; all had normal ventricular function under rest conditions. Myocardial contractility was assessed by means of continuous two-dimensional echocardiographic monitoring; coronary reserve was evaluated by coronary sinus thermodilution. After dipyridamole infusion, 9 of the 19 patients with left anterior descending artery stenosis had transient myocardial asynergy involving the septum or apex, or both (Group IA), whereas 10 patients showed no asynergy (Group IB). No impairment of contractility was observed in the 10 patients with normal coronary arteries (Group II). Coronary blood flow was measured under basal conditions and up to 10 minutes after the end of dipyridamole infusion. In patients in Group II, dipyridamole induced an increase in great cardiac vein flow of 167 +/- 68% (mean +/- SD). The 10 patients in Group IB showed a response comparable with that of the control group (Group II) (136 +/- 45% increase in great cardiac vein flow; NS versus Group II), whereas the 9 patients in Group IA had an increase of 46 +/- 30% (p less than 0.01 versus both Group IB and Group II). No significant difference was found in the angiographic severity of the stenosis expressed in terms of minimal cross-sectional area (Group IA = 0.30 +/- 0.13 mm2, Group IB = 0.34 +/- 0.18 mm2; p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

High dose dipyridamole echocardiography test in effort angina pectoris.

The dipyridamole echocardiography test (intravenous dipyridamole with two-dimensional echocardiographic monitoring) was performed in 93 patients with effort chest pain and in 10 control subjects. The test was considered positive when regional asynergy appeared after dipyridamole administration. When negative at the low dose (0.56 mg/kg body weight in 4 minutes), the test was repeated on a different day with a higher dose (0.84 mg/kg in 10 minutes). All 93 patients underwent coronary arteriography; 72 of them had significant (greater than 70% luminal reduction) coronary artery disease. Thirty-eight of the 93 patients had a positive low dose dipyridamole echocardiography test; 15 other patients with a negative low dose test had a positive high dose test. All 53 patients with a positive test had significant coronary artery disease; 12 of them had a negative exercise stress test. In relation to the presence of coronary artery disease, the dipyridamole echocardiography test had an overall specificity higher than that of the exercise stress test (100 versus 71%) and a similar overall sensitivity (74 versus 69%). The dipyridamole echocardiography test is feasible in all patients with a good baseline echocardiogram. It detects the site of apparent ischemia more precisely than does an exercise stress test, and can unmask electrocardiographically silent ischemia. If performed in patients with a negative low dose dipyridamole echocardiography test, the high dose test adds sensitivity (probably by achieving maximal dilation in patients in whom the low dose is only partially effective), without any loss in specificity and with no apparent increase in risk.

Adult↗
PubMed1986

Early post-infarction angina: usefulness of dipyridamole-echocardiography test.

Thirty-nine patients with early post-infarction angina (all with significant, angiographically assessed coronary artery disease and a baseline asynergy on 2-D echo), performed a dipyridamole-echocardiography test (DET: 2-D echo monitoring with dipyridamole infusion, 0.14 mg kg-1 min-1 for 4 min). Twenty-nine patients had a positive DET (sensitivity = 74%). Two mechanical patterns of DET-positivity could be identified: a worsening of the asynergy in that same region showing a baseline asynergy (11 patients); a 'de novo' asynergy in a region remote from the one showing a baseline asynergy (18 patients); The prevalence of single-vessel disease was significantly higher in patients with type 1 positivity pattern (6 single-, three double- and two triple-vessel disease), while patients with type 2 positivity always showed a multivessel coronary involvement (8 double-, 10 triple-vessel disease). In 4 of the 10 patients with 3-vessel disease and type 2 asynergy, such asynergy developed in a territory different from the one supplied by the more stenotic non-infarct-related vessel. In conclusion, DET represents a safe and feasible tool effectively to localize ischaemia, relative to the infarcted region, and to evaluate the haemodynamic significance of coronary lesions in patients with post-infarction angina.

Adult↗
PubMed1986

Echocardiography in the study of myocardial ischemia in man: the clinical model of Prinzmetal's angina.

Standard echocardiography was employed to study the clinical model of myocardial ischemia with ST-segment elevation, well known as Prinzmetal's angina. Ultrasonic monitoring was performed during the appearance of ST-segment elevation, from onset of pain, during an ergonovine maleate test, hemodynamic monitoring, radioisotopic studies and, occasionally, during routine examinations, when spontaneous episodes occurred. Reliability of findings was supported by two important conditions: each patient acted as his own control, since recording was carried out from basal state to basal state, throughout ischemia, or from ischemia to basal state; behaviour of ischemic walls was compared with that of non-ischemic ones. Echocardiographic findings in acute myocardial ischemia were similar both in spontaneous and in induced episodes and were mainly characterized by: decrease in contractility indices of the ischemic segment, such as wall motion and percent systolic thickening; increase in left ventricular end-systolic and end-diastolic diameter, with a decrease in percent fractional shortening; distorted shape of ventricular cavity, transiently deformed as in a "functional" aneurysm; a sharp demarcation between ischemic and non-ischemic adjacent segment, "step sign", was present only in severe cases. Taking ST-segment elevation as a reference the time sequence of events was studied, correlating mechanical, electric and clinical markers of ischemia. At least three different echocardiographic phases were identified in the evolution of ischemic attacks: Pre-electrocardiographic phase, when mechanical impairment is detected by ultrasounds in the absence of both ST-segment changes and pain; Electrocardiographic phase, when echocardiographic signs of ischemia co-exist with obvious electrocardiographic signs.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris, Variant↗
PubMed1986

Echocardiographic documentation of myocardial ischemia in presence of angina pectoris without ST-T changes.

A frequent clinical problem is to document the elusive entity of electrocardiographically silent myocardial ischemia. Since echocardiography offers a practical tool to detect reversible mechanical changes due to ischemia, 32 patients with angina on effort, and coronary artery disease, and 15 patients with angina at rest were studied. In all 47 patients electrocardiographic changes during effort or rest pain were inconclusive. Combined 12 lead electrocardiographic and 2-Dimensional echocardiographic monitoring were performed: during ergonovine testing in the 15 patients with angina at rest; during dipyridamole testing in the 32 patients with effort angina and a non diagnostic stress test. Interpretable echocardiograms were obtained in all the patients studied. Positivity of both the Ergonovine-Echocardiographic test and the Dipyridamole-Echocardiographic test was based upon the detection of regional transient asynergy. Of the 15 patients who had chest pain at rest in the absence of diagnostic electrocardiographic changes, Ergonovine-Echocardiographic test was positive in 6 (40%). Of the 32 patients who had chest pain in absence of diagnostic electrocardiographic changes during exercise stress testing, the Dipyridamole-Echocardiographic test was positive in 18 (56%). Echocardiographic monitoring in combination with provocative testing (ergonovine and dipyridamole) may be a practical, non invasive, inexpensive tool which is feasible in all patients with good basal echocardiograms and is able to unmask electrocardiographically silent myocardial ischemia by providing objective mechanical evidence of the ischemic event.

Adult↗
PubMed1985

Dipyridamole-echocardiography test in effort angina pectoris.

This study assesses the clinical feasibility and usefulness of dipyridamole infusion for the detection of coronary artery disease (CAD) by using 2-dimensional echocardiography (2-D echo) and 12-lead electrocardiographic monitoring. Dipyridamole infusion (0.14 mg/kg/min for 4 minutes) was performed in 66 consecutive patients with effort chest pain and in 9 control subjects. Among the 28 patients with positive dipyridamole-echocardiography test responses, 18 had diagnostic electrocardiographic changes (ST-segment depression on anterolateral leads), but these changes were unrelated to the site of asynergy. The dipyridamole-echocardiography test had an overall sensitivity of 56% and specificity of 100% for the presence of CAD. Exercise stress testing (EST) had an overall sensitivity of 62% and a specificity of 80%. Thus, the dipyridamole-echocardiography test, which is feasible in essentially all patients with good basal echocardiograms, has a lower overall sensitivity in detecting CAD than EST but a higher specificity, detects the site of apparent ischemia as identified by regional asynergy more precisely than EST, and can unmask electrocardiographically silent effort ischemia.

Adult↗
PubMed1985

Angle dependence of ultrasonic backscatter in arterial tissues: a study in vitro.

The object of this study was to obtain quantitative data on the angle dependence of reflected ultrasound signals in freshly excised normal human arterial walls and those with different degrees of atherosclerotic involvement (fatty, fibrofatty, fibrous, or calcified). Fifteen specimens were evaluated in each pathologic subset. The backscatter coefficient (BS, expressed as cm-1 X steradians -1), measured at the single frequency of 10 MHz, was evaluated at a normal angle of incidence of the interrogating beam to the tissue sample and over an angular span of 60 degrees (+/- 30 degrees around normal incidence, 2 degree steps). BS measured at normal incidence separated normal (10(-2) X 0.155 +/- 0.018; mean +/- SE) from fibrofatty (10(-1) X 0.0103 +/- 0.008), fibrous (10(-1) X 0.182 +/- 0.016), and calcified (0.202 +/- 0.016) specimens; normal and fatty (10(-3) X 0.759 +/- 0.142) and fibrofatty and fibrous samples could not be distinguished from each other in a statistically significant way. Angular scattering measurements identified two patterns: A "directive" pattern, characterized by a strongly angle-dependent BS that falls abruptly when the beam is moved slightly away from normal incidence. This pattern was typical of calcified, fibrous, and less markedly, fibrofatty and normal samples. A "nondirective" pattern, characterized by a BS that is not significantly angle dependent and fluctuates throughout the entire angular range. This was typical of fatty samples.

Aorta↗
PubMed1985

[Cardiac sudden death. Testing of an extra-hospital emergency system].

From December 1979 to April 1984, 266 victims of cardiac arrest outside the hospital in the metropolitan area of Florence received advanced cardiopulmonary resuscitation by a system for medical emergencies. 69 patients (25.9%) were successfully resuscitated and 42 (15.7%) were discharged alive from hospital without any neurological damage. The time delay between the onset of the cardiac arrest and the cardio-pulmonary resuscitation, the cardiac rhythm present on arrival of rescue squad, the degree of congestive heart failure immediately before the cardiac arrest and the neurological deficit after resuscitation significatively influenced immediate and late outcome.

Ambulances↗
PubMed1984

[Electrophysiologic characterization of propafenone in man].

We performed an electrophysiologic study in 10 subjects before and after administration of Propafenon in doses of 1,5 mg/Kg b.w. i.v. in 2-3 minutes. No symptoms and no significant reductions of arterial blood pressure were observed. The analysis of our data shows that Propafenon does not significantly influence the sinus node function and the sinoatrial conduction. As far the atrioventricular conduction, the drug caused a significant increase of the Wenckebach point, of St-Q interval duration and of the A-V node absolute refractory period. The H-V interval and the His-Purkinje refractory period were also increased. We conclude that P exerts a negative dromotropic effect by direct pharmacological action on the A-V node and on the intraventricular specific conduction pathways.

Anti-Arrhythmia Agents↗
PubMedDate not supplied

In vivo radiofrequency ultrasound analysis of normal human heart structures.

Twenty young subjects were studied with a microprocessor system for quantitative analysis of backscattered radiofrequency (RF) signals from normal heart structures. This system allows an "on line" quantitative evaluation of the amplitude of the RF "native" signal, before the chain of processing and display, with the acquisition gate displayed on a conventional M-mode machine. Septum, posterior wall, and anterior mitral leaflet were analyzed. The gate length was kept at 3 microseconds (2.35 mm) for the ventricular walls (excluding endo- and epicardial reflections), and at 1 microsecond (0.8 mm) for the mitral valve. Integrated backscatter index (IBI) was calculated as the time integral of [u(t)[, where u(t) = i(t) X s(t); is the time sequence of backscattered echoes and s(t) is the time gate delimiting the thickness of the insonated tissue. The IBI was expressed in percent, normalized for the pericardial interface (the strongest reflection was assumed to be 100%). The percent IBI for the septum was found to be 22 +/- 4%; for the posterior wall it was 17 +/- 3%; for the anterior mitral leaflet it was 5 +/- 2%. A second reading of the same structures was performed by the previous observer and by a new one. Good intraobserver (r = 0.92) and interobserver (r = 0.88) correlations were obtained. In conclusion, a regional variation in echo amplitude from different heart structures can be observed in man. This set of values can be used as normal values for future studies in pathologic conditions.

Adult↗
PubMedDate not supplied

Levels of anxiety and pain during chemotherapy with peripheral versus central vascular access: an experimental evaluation.

PURPOSE: The purpose of this research was to evaluate pain and anxiety levels in patients undergoing chemotherapy via central venous catheter (CVC) and peripheral venous access (PVA). METHOD: The sample consisted of 56 cancer patients undergoing at least one chemotherapy treatment cycle. They were divided into two groups based on the administration method of the chemotherapeutic drug: the experimental group (patients with CVC) and the control group (patients with PVA). The instruments used were the following: for multidimensional pain evaluation the Italian Pain Questionnaire (QUID, devised by De Benedettis et al), and the Visual Analogue Scale (VAS) Chart of Pain. To evaluate the state and anxiety traits, the State-Trait Anxiety Inventory (STAI questionnaire, by D. Spielberg) was used, and we used structured interviews for the statistical survey. RESULTS: Analyzing the data from the STAI questionnaire, it appeared that the state-trait anxiety levels of the experimental group and the control group were not significantly different (analysis of the mean difference made using the Student's t-test). The average scores of the STAI questionnaire for both groups fell within the normal range. This indicated that the anxiety level was unaffected by the introduction of the device (the CVC). The data collected with the QUID questionnaire and subsequent statistical analysis demonstrated that the difference between the means (Student's t-test) of the experimental group and the control group was significantly lower, as regards perception of the sensorial and evaluative quality of pain (p=0.05) in the experimental group. From the evaluation of the VAS method, it appeared that the difference between the means was not significant in either group, although the distribution of frequency tended towards lower values in the experimental group with respect to the control group. This confirms previous QUID research where a lower pain level is recorded. CONCLUSIONS: Analysis of the data collected via the structured interview revealed that most of the CVC sample did not respond to catheter insertion as a sign of a worsening of their illness.

Journal Article↗