PubMed Health⌕ Search

Biomedical subjects

F Meinardi

Publications and source records attributed to F Meinardi.

14 recordsLinked to original sources
PubMed2003

Superradiance in molecular H aggregates.

Direct evidence of superradiance from an organic semiconductor (quaterthiophene) whose molecules are arranged in a H aggregate fashion, is reported. Time resolved photoluminescence measurements show a linear correlation between the radiative lifetime (tau(rad)) of the purely electronic exciton recombination and the inverse of the number (N(C)) of the coherently emitting dipoles, i.e., tau(rad) proportional, variant 1/N(C). These data support the recently developed theoretical models describing the optical properties of H aggregates of rodlike molecules with a nonvanishing component of the perpendicular molecular transition dipole moment.

Journal Article↗
PubMed2002

Intrinsic excitonic luminescence in odd and even numbered oligothiophenes.

The emission properties of crystalline oligothiophenes (OTs) are investigated and related to the different selection rules arising from the number of rings. In odd OT crystals the purely electronic emission is absent since the molecular A1-1B(1) transition dipoles cancel at the bottom of the excitonic band. On the contrary, in crystals of even OTs this transition is allowed due to the constructive interference of the off-axis components of the molecular transition dipole. It possesses a polarization in the herringbone plane and exhibits superradiant behavior.

Journal Article↗
PubMed2000

Myocardial infarction with acute thrombosis of multiple major coronary arteries: a clinical and angiographic observation in four patients.

Four patients are reported in whom concomitant obstructive thrombosis of two major coronary vessels was observed at coronary angiography during evolving myocardial infarction. In all cases the simultaneous involvement of both vessels as the cause of acute ischemia was confirmed by the results of sequential treatment of the lesions with emergency angioplasty.

Acute Disease↗
PubMed1998

Early aggressive treatment of unstable angina without on-site cardiac surgical facilities: a prospective study of acute and long-term outcome.

BACKGROUND: The early invasive diagnostic approach with extensive use of myocardial revascularization in patients with unstable angina is a matter of debate. Both the advantages of this strategy and the choice of the best candidates are controversial. The widespread applicability of this approach in Italian hospitals is also questionable, due to limited availability of facilities for interventional cardiology. METHODS: A prospective, observational study was done on a cohort of consecutive patients, who were admitted with a diagnosis of unstable angina and treated with an early aggressive approach at a center with interventional cardiology facilities without cardiac surgery. The aim of the study was to evaluate both the immediate and long-term clinical outcome of patients and the efficiency of our therapeutic approach. RESULTS: Two-hundred and two patients were enrolled and 85% were in Braunwald class III. Coronary angiography was performed in 171 patients (85%) at 2.1 +/- 2.4 days after admission: it showed one-, two- and three-vessel disease in 40, 29 and 22% of cases, respectively; 9% of patients had no severe coronary lesion. Left ventricular ejection fraction was 0.58 +/- 0.13. Medical treatment, coronary by-pass surgery and percutaneous myocardial revascularization were chosen in 36, 24 and 40% of cases, respectively. Coronary angioplasty was performed in our center in 58 (73%) of 80 patients at 6.8 +/- 5.6 days after admission and stents were used in 42 cases (74%). Overall hospital stay was 10.4 +/- 4 days. Cumulated adverse events (death and non-fatal myocardial infarction) occurred in 2.5 and 7% of patients during the initial admission and in the following year, respectively. CONCLUSIONS: An early aggressive approach to patients with unstable angina is feasible in a hospital with interventional cardiology in the absence of cardiac surgical facilities. The immediate favorable clinical results of this strategy in an intermediate-risk cohort seem to persist at one-year follow-up.

Adrenergic beta-Antagonists↗
PubMed1998

[Primary angioplasty in acute inferior myocardial infarct with anterior ST-segment depression: the long-term follow-up].

BACKGROUND: Concomitant anterior ST-segment depression is a marker of severe prognosis in inferior myocardial infarction. PATIENTS AND METHODS: Prospective observational study in patients with inferior acute myocardial infarction and ST-segment depression > or = 4 mm in the anterior leads, who were treated with primary angioplasty. Angiography was performed at hospital discharge and at six months, and a clinical follow-up was obtained at one year after the infarction. RESULTS: Sixty-three patients were included in the study. Pre-hospital and in-hospital delay were 147 +/- 70 minutes (20-355) and 54 +/- 11 minutes (18-80), respectively. Angioplasty was successful in all patients and 48 stents were implanted in 36 patients (57%). Angiography was performed at hospital discharge in 55 patients (87%) and showed a TIMI grade 3 coronary flow in the infarct-related artery in all cases. The left ventricular ejection fraction was 0.55 +/- 0.09 (0.4-0.8). One patient (1.6%) died before discharge, two (3.2%) had ischemic complications (one had non-fatal reinfarction, another had recurrent angina at rest), and three (4.9%) had local vascular complications. At the six-month follow-up, none of the patients had died. One had suffered reinfarction (1.6%) and another had been readmitted for recurrence of angina at rest (1.6%); none had symptoms of stable angina. The ejection fraction was 0.56 +/- 0.12 and eight patients (14%) showed angiographic restenosis. At twelve months, two patients had died (1.6%) and five (8%) had required readmission to hospital. CONCLUSIONS: Primary angioplasty yielded favorable results in this group of patients. Our data confirm the efficacy of primary angioplasty for the treatment of acute myocardial infarction, with a low rate of clinical (3.2%) and angiographic (14%) restenosis at six months, and a high rate (87%) of event-free survival at one year follow-up.

Adult↗
PubMed1996

[The use of a check list for quality assurance of the treatment of acute myocardial infarction in the coronary care unit].

UNLABELLED: The implementation of Quality Assurance programs for the treatment of acute myocardial infarction in the Cardiac Intensive Care Unit may be specially important. In fact several therapeutic options are available in these patients, and delay in treatment must be as short as possible. A Quality Assurance program has been started in our center with a registry of all patients admitted within 24 hours of onset of acute myocardial infarction. PATIENTS AND METHODS: The following data were recorded: 1) indicators of Organization: pathway to admission, pre-hospital and in-hospital delay; 2) Process Indicators: duration of hospital stay, initial choice of therapy (conservative, intravenous lysis, primary angioplasty), and further diagnostic and interventional procedures; 3) Outcome Indicators: mortality and complications during admission, and 6-12 months follow-up. RESULTS: Since february 1994 to August 1995, 211 consecutive patients were included in the registry; 156 were male, mean age 66 years. Mean pre-hospital delay was 286 minutes. Admission was decided by a physician in 99 cases and by the patient him/herself in 112 cases; pre-hospital delay was 390 min. In the former group, and 194 min. In the latter (p < .001). Mean in-hospital delay was 61 minutes. Conservative treatment, intravenous lysis, and primary angioplasty were chosen by the attending cardiologist in 89 patients (group A), 69 patients (group B), and 53 patients (group C) respectively. The latter group included patients with highest risk on the basis of clinical and electrocardiographic characteristics. In-hospital mortality was 17, 7 and 9% In the 3 groups, respectively. An echocardiogram and coronary angiography were performed before discharge in 81% and 57% of patients, respectively. The mean duration of hospital stay was 11 days, irrespective of the initial therapeutic choice. CONCLUSIONS: A registry for patients with acute myocardial infarction provides information which is essential in the evaluation of therapeutic protocols; it may also help in improving the cooperation between the Emergency Department, the attending cardiologists, and the family physicians.

Aged↗
PubMed1995

[Emergency angioplasty in high-risk acute infarct].

BACKGROUND: Primary coronary angioplasty in acute myocardial infarction yields superior results in terms of effective vessel patency, recurrent ischemia and acute morbidity, as compared to intravenous thrombolysis. Despite obvious logistic and economic limitations, this early invasive approach could be strictly indicated in selected groups of patients. AIM: A prospective study to test the immediate and short-term results of an early invasive strategy with angioplasty in patients with high-risk acute myocardial infarction. METHODS: Forty-one consecutive patients with high-risk acute myocardial infarction were submitted to coronary angiography and angioplasty of the involved vessel within 12 hours of onset of symptoms. Twenty-eight had anterior myocardial infarction and 6 were in cardiogenic shock. RESULTS: Primary success was achieved in 38 patients (93%): 30 of these were discharged without complications or further revascularization procedures, and none has symptoms or re-infarction at one-month follow-up. CONCLUSIONS: Immediate invasive treatment with angioplasty in high-risk acute myocardial infarction seems to achieve good results, due to both effective infarct vessel recanalization, and early identification of candidates to urgent complete surgical revascularization.

Adult↗
PubMed1990

[Risk stratification after uncomplicated myocardial infarct: the usefulness of the echocardiographic-dipyridamole test].

To assess the value and safety of echo-dipyridamole test in risk stratification soon after an uncomplicated acute myocardial infarction, 56 consecutive patients were enrolled in a prospective study with a 1-year follow-up period for new coronary events. Echo-dipyridamole and symptom-limited ECG stress test were performed respectively 14 to 20 days and 4 to 5 weeks after acute event. Echo-dipyridamole test was performed administering 0.84 mg/kg iv of the drug in 10 min: any worsening of left ventricular regional wall motion was considered as a positive test. Up to December 1989, 43 out of 56 patients had their follow-up period completed: the infarction was anterior in 13 (30%), inferior in 22 (51%), non-Q wave in 8 (19%); mean age was 55 +/- 10; basal echocardiographic ejection fraction was 52 +/- 6%. There were no major complications during echo-dipyridamole test. Coronary events occurred in 7 patients (16%): reinfarction in 3, angina in 4; there were no cardiac deaths. A positive echo-dypiridamole test was observed in 12/43 patients (28%); sensitivity versus coronary events was 43%, specificity 75%, negative predictive value 87%. Ten out of 43 patients (23%) had positive and 9/43 (21%) non valuable ECG stress test: sensitivity versus coronary events was 50%, specificity 75%, predictive negative value 88%. The 2 tests showed no significant difference in detecting patients at risk of future coronary events.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[A study of the variations in myocardial perfusion induced by systemic thrombolysis in acute myocardial infarct using sequential scintigraphy with 201-thallium].

To assess scintigraphic changes induced by intravenous streptokinase therapy, serial rest redistribution thallium-201 perfusion imaging was performed in 62 patients with acute myocardial infarction lasting less than 6 hours. Twenty-seven patients randomized to treatment with intravenous streptokinase (group A) and 35 to conventional therapy (group B) underwent thallium-201 scintigraphy as soon as possible after admission to the coronary care unit (early study). Regional myocardial perfusion was assessed using thallium-201 scintigraphy 7-9 days later in each patient (late study). The size of the perfusion defect was evaluated using a semi-quantitative score. The size of the perfusion defect decreased in serial scans in both group A (preintervention score: 12.1 +/- 6.8; redistribution score: 11.4 +/- 6.8; late study: 8.8 +/- 7.0) and group B (12.8 +/- 6.5; 12.3 +/- 6.7; 10.6 +/- 7.5, respectively). No statistical difference in myocardial perfusion was found between the two groups, on late study. Peak serum creatine kinase MB (CKMB) was earlier in group A than in group B (1030.8 +/- 326.6 vs 1361.0 +/- 271.1: p less than 0.001). The fast CKMB release group (onset of symptoms-peak of CKBM less than or equal to 900 minutes) exhibited higher thallium-201 uptake when compared to the slow CKMB release group, at the time of late study (perfusion defect score: 6.1 +/- 5.7 vs 10.7 +/- 7.3: p = 0.03). Reversibility was observed in 21/62 patients (34%). Reversibility corresponded to unchanged or improved perfusion defect score on late study in 18/21 patients (86%). Nevertheless 20/41 (49%) patients not showing redistribution of thallium-201 within pre-treatment defect had an improvement in regional perfusion on late study. Reversibility was observed in 9/14 (64%) patients with fast CKMB release and in 12/47 (26%) patients with slow CKMB release. We conclude that the early peak of CKMB is associated with a higher uptake of thallium-201 on late study. Furthermore, the reversibility of perfusion defect on redistribution imaging forecasts evolution of scintigraphic perfusion, but, when this is not present, it doesn't rule out late improvement of thallium-201 myocardial uptake. The low sensitivity and specificity of redistribution imaging and the procedure related delay in instituting therapy make thallium-201 scintigraphy unreliable in the evaluation of myocardial reperfusion following thrombolysis.

Adult↗
PubMed1983

[Work capacity evaluation in patients with valvular prostheses].

The possibility of evaluating the capacity for work of subjects wearing heart valve prostheses is analysed. The many factors affecting the return to normal life after operations for valvulopathies are not considered. In strictly medical terms cardiac terms cardiac function can be adequately evaluated by anamnestic and clinical surveys, supplemented by standard non-surgical instrumental examination with particular emphasis on echography, computerised radioisotope angiocardiography and physical exertion tests.

Aortic Valve↗
PubMed1981

[Treatment using radiofrequency stimulation of supraventricular paroxysmal tachycardia in W.P.W. syndrome].

The case of woman patient suffering from W.P.W. syndrome and recurrent attacks of supraventricular paroxysmal tachycardia refractory to medical treatment is reported. After electrophysiological study, a radiofrequency coil is implanted. This is activated by the patient during attacks and leads to rapid interruption. The modalities under which paroxysmal tachycardias are interrupted by means of electrostimulating units are discussed and indications for radiofrequency stimulation assessed.

Cardiac Pacing, Artificial↗