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Biomedical subjects

C Greco

Publications and source records attributed to C Greco.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Contractility and left ventricular filling in heart failure: an echocardiographic evaluation].

In this paper we analyze the possibility of investigating the various modalities of pump function alteration by the echocardiographic technique through examination of the different parts of the cardiac cycle. While M-Mode and 2D echocardiography make a precise assessment of the systolic function parameters possible, with the Echo-Doppler technique we can study diastolic function and obtain information about many hemodynamic parameters. "Strain dependent" and "strain independent" diastolic function are studied almost exclusively with the Echo-Doppler technique: the diagnosis of restrictive cardiomyopathy can be established without invasive procedures such as cardiac catheterization. We suggest that, in most heart diseases with cardiac failure, diastolic and systolic dysfunction coexist: in mitral and aortic regurgitation, echocardiography can give precise information on the presence of ventricular dysfunction, even in the presence of very few or no symptoms, which helps the cardiologist make an early surgical or non surgical decision when dealing with such valve pathologies.

Cardiomyopathies↗
PubMed1992

[Anatomo-functional study of non-rheumatic mitral insufficiency with transesophageal echocardiography].

Reconstruction surgery of the mitral valve has become an alternative to mitral replacement in patients with pure mitral regurgitation. Preoperative assessment of the anatomic and functional aspects of the valvular lesion is of the utmost importance in conservative surgery. Transesophageal echocardiography is a new approach to investigating the mitral valve, and our study was undertaken with the purpose of determining its importance in the exploration of mitral regurgitation of non-rheumatic origin. Subjects included were twenty patients with pure and isolated mitral regurgitation (MR): 14 males and 6 females with an average age of 47 +/- 13 years. All the patients underwent a first transesophageal 2D and color Doppler echocardiographic examination, and 5 of them underwent a second one during cardiovascular surgery. Mitral anulus diameter, mitral valve cordae tendinae status, valvular leaflet length and coaptation were examined and color Doppler regurgitation jet area was measured. Mitral anulus diameter was 40.2 +/- 8.06 mm (diastolic) and 41.9 +/- 8.53 mm (systolic) and was above the values considered to be normal. Anterior leaflet length was 30.8 +/- 3.12 mm and posterior leaflet length was 22.9 +/- 4.74 mm; regurgitation jet area was between 1.2 cm2 and 13.52 cm2 with an average of 5.44 cm2. In the group with MR of mixomatous origin, systolic anulus diameter showed a linear correlation with regurgitation jet area (r = 0.79). In the 6 patients who underwent cardiac catheterization, angiographic semiquantitative evaluation of the MR confirmed that based on color Doppler jet area. In all twenty patients transesophageal echocardiography enabled us to identify the mechanism responsible for mitral insufficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Transcatheter ablation of the accessory pathway in 2 patients with life-threatening tachyarrhythmias.

Successful transcatheter ablation of an accessory pathway in 2 patients with life-threatening tachyarrhythmias is reported. In both cases, electrophysiological evaluation documented the posterior septal location of the anomalous atrioventricular connection. Radiofrequency current energy was delivered just below the coronary sinus orifice, and resulted in disappearance of preexcitation. During the follow-up, both patients remained free from tachyarrhythmias on no medication, and serial electrocardiographic recordings confirmed the persistent absence of preexcitation. It is concluded that ablation of accessory pathways can be accomplished easily and without risk by means of the radiofrequency catheter technique. This therapeutic modality requires a short hospitalization and can be recommended as the first option in patients with the Wolff-Parkinson-White syndrome.

Adult↗
PubMed1992

[Propafenone versus hydroquinidine in long-term pharmacological prophylaxis of atrial fibrillation].

New antiarrhythmic class 1C agents have been proposed in the last few years in an attempt to suppress paroxysmal atrial fibrillation at long-term, as the most commonly used class 1A agents such as quinidine gave highly variable results as regards both side-effects and efficacy. The aim of this randomized prospective study is to evaluate the efficacy and safety of oral propafenone at long term in preventing paroxysmal atrial fibrillation and to compare the results with those obtained using agents such as quinidine. Two hundred patients with recurrent episodes of symptomatic atrial fibrillation were enrolled for this study with entry criteria based upon a history of more than 3 crises in the previous 6 months, with electrocardiographic (standard electrocardiogram or dynamic registration) documentation. According to a randomized selection either propafenone at 300 mg twice daily or hydroquinidine retard 250 mg twice daily were administered to the patients; clinical check-up was carried out every 3 months or if clinical course worsened. The dosages were increased if proved to be inadequate at check-up (i.e. recurrence of atrial fibrillation) up to 300 mg 3 times daily for propafenone and 500 mg twice daily for hydroquinidine. The efficacy at the 3rd month was 71% for propafenone and 60% for hydroquinidine, at the 6th month 60% for propafenone and 56% for hydroquinidine; this trend lowered progressively as the follow-up continued, to 48% for propafenone and 42% for hydroquinidine (NS). More than 70% of the responder patients assumed 600 mg twice for propafenone or 250 twice for hydroquinidine. Propafenone had a percentage of 10% side-effects and hydroquinidine 24% (p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Different effects of sequential combinations of N-methylformamide with 5-fluorouracil on human colon carcinoma cells growing in nude mice.

The effects of the combination of N-methylformamide (NMF) with 5-fluorouracil (5-FU) on tumor growth and morphological features of human colon carcinoma cells (HT29) implanted in nude mice were assessed. Both agents were administered i.p. at tolerable doses: 5-FU at 19 mg/kg for 5 days and NMF at 200 mg/kg for 12 days. Four main schedules were tested: 5-FU alone, NMF alone, NMF followed by 5-FU and 5-FU followed by NMF. The last sequence was the most effective, as compared with the other treatment regimens. In particular, the 5-FU----NMF combination induced a tumor inhibition of about 75% at the end of the treatments (17th day) versus an inhibition of 23%-43% in the other schedules. Morphological observations, carried out by light and electron microscopy, indicated a possible relationship between the presence of structural changes and tumor growth inhibition. The results of this study renew interest in the use of NMF in sequential combination confirming sequence as a critical factor for the optimal combination of NMF and 5-FU.

Adenocarcinoma↗
PubMed1991

A case of Rhodococcus equi brain abscess.

We treated a patient with acquired immunodeficiency syndrome for a brain abscess caused by Rhodococcus equi, an actinomycete that usually infects the lung in immunosuppressed hosts. Rhodococcus equi brain abscess is an extremely rare lesion that has never been reported in a patient with acquired immunodeficiency syndrome. The infection was cured by lengthy therapy with multiple antibiotics after aspiration of the lesion to identify the infective organism and determine its sensitivity to antibiotics.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Infarct of the conus medullaris simulating a spinal cord tumor: case report.

A 71-year-old woman had the sudden onset of a neurogenic bladder and a stepwise increase in paraparesis that left her unable to stand or walk. Magnetic resonance imaging showed what appeared to be a tumor in the conus medullaris. After laminectomy, the lesion was localized by ultrasound examination, and a biopsy was performed. The deficits remained unchanged postoperatively. Microscopic examination of the biopsy specimen showed necrosis and pathologic changes consistent with infarction of the conus medullaris. An anomalous arterial supply of the conus medullaris is the most likely cause of this unusual problem. The patient gradually regained her ability to walk, but the neurogenic bladder persists.

Aged↗
PubMed1991

[The transcatheter modulation of the AV node as a possible treatment of choice in nodal re-entrant tachycardia].

Transcatheter modification of the AV node with radiofrequency energy (RF) was performed in 6 patients (mean age 24 years) with inducible AV node reentry tachycardia (AVNRT). Although tachycardia could be controlled with antiarrhythmic drugs in each patient, the option was offered to eliminate the arrhythmia by means of RF catheter technique. A 7F catheter with 2 mm interelectrode distance and a large tip electrode was positioned to record the maximal His deflection, then withdrawn until the smallest possible His and ventricular potentials with a large atrial signal could be recorded. RF energy was delivered at this site in unipolar mode in incremental steps, until AVNRT was no longer inducible or VA block occurred. The procedure resulted in non-inducibility of tachycardia in 5/6 patients. The fast and the slow pathways were abolished in 2 and 1 patients, respectively, while the AV node duality persisted in 2 in spite of non-inducibility. VA block occurred in 2 patients, while the anterograde conduction was preserved in all. During the follow-up (mean 4.5 months) 5/6 patients remained free of AVNRT without drugs. It is concluded that transcatheter RF modulation of the AV node can be advised, provided that similar results will be obtained in larger series with longer follow-up, as the first line therapy in patients with AVNRT.

Adolescent↗
PubMed1991

[Relations between ACE inhibition with captopril and atrial natriuretic factor during an acute hemodynamic study].

Aim of this study was to evaluate if captopril treatment may directly alter the trial natriuretic factor (ANF) concentration. Six patients (2 male and 4 female) aged 53 +/- 11 years, with mitral stenosis, and atrial fibrillation, underwent cardiac catheterization in our Institution. The following parameters were evaluated: heart rate, right atrial and pulmonary capillary wedge pressure, aortic and pulmonary pressure, cardiac index, pulmonary and systemic resistances and ANF concentration in coronary sinus, pulmonary, artery, aorta, peripheral vein. All these parameters were measured before and 30 and 60 min after captopril administration (50 mg orally). No hemodynamic changes occurred after captopril administration. No changes in ANF concentration occurred in comparison with baseline levels, after 30 and 60 min in coronary sinus (199.8 +/- 151.5 vs 181.9 +/- 102.5 fmol/ml; 178.4 +/- 95.2 vs 181.9 +/- 102.5 fmol/ml), in pulmonary artery (58.3 +/- 36.6 vs 51.4 +/- 48.8 fmol/ml; 35.5 +/- 16.9 vs 51.4 +/- 48.8 fmol/ml), in aorta (29.7 +/- 22.7 vs 37.5 +/- 26.3 fmol/ml; 25.2 +/- 9.8 vs 37.5 +/- 26.3 fmol/ml); and in peripheral vein (14.6 +/- 7.9 vs 17.3 +/- 9.7 fmol/ml; 16.2 +/- 12.2 vs 17.3 +/- 9.7 fmol/ml). In conclusion our data show that, providing no hemodynamic changes occur, captopril administration does not alter ANF concentration.

Adult↗
PubMed1991

[The transcatheter ablation of arrhythmias].

The introduction of transcatheter ablation techniques has opened a new era of the management of tachyarrhythmias. The rationale of these therapeutic procedures lies in the induction of an irreversible and limited damage to cardiac tissue involved in arrhythmias. In its original form, the technique involves the delivery of high energy DC discharges (fulguration) to the target area through a temporary catheter electrode. A primary drawback of fulguration, when used for ablation of AV node-His bundle, is the induction of a pacemaker-dependent state; the barotraumatic effect that results from high energy impulses constitutes the major limitation in the case of ablation of accessory pathways or arrhythmogenic areas. Recently, the efficiency of the procedure has been substantially improved by the use of low-power, high-frequency alternating current (radiofrequency), that allows to deliver graded amounts of disrupting energy to selected areas while avoiding undesirable biophysical effects to the surrounding tissue. Remarkable results, with a success rate close to 100%, are reported with radiofrequency ablation of AV node reentry tachycardia, as well as reciprocating tachycardia associated with the preexcitation syndrome, so that this technique can be considered the procedure of choice for both categories of patients. Catheter modification of AV conduction provides a therapeutic tool for treating atrial tachyarrhythmias with rapid ventricular responses. In such cases, however, the risk of AV block with the need for pacemaker implantation must be taken into account. Results of catheter ablation of ventricular tachycardia have been inconstant and generally disappointing, except for ventricular tachycardias due to reentry in the His-Purkinje system, for which a high success rate is reported. Experience with radiofrequency ablation in ventricular tachycardia is very limited, but localization of a critical segment of reentry could improve the efficiency of this technique.

Arrhythmias, Cardiac↗
PubMed1990

Enhancement of hyperthermic damage on M14 melanoma cells by liposome pretreatment.

Exponentially growing human melanoma cells (M14 cell line) were pretreated with various amounts of dipalmitoylphosphatidylcholine-containing multilamellar liposomes and then exposed to heat treatment (42.5 degrees C). Cell damage produced by the treatments, given separately or in combination, was evaluated in terms of cell survival. Our results demonstrate that the cell survival at 37 degrees C was not affected by liposome concentrations up to 1000 nmol of phospholipid/2.5 x 10(6) cells, while liposome treatment of cells before heat exposure determined a marked damaging effect even at 100 nmol of phospholipid/2.5 x 10(6) cells. The mechanisms of liposome-cell interaction have been investigated by electron microscopy or by electron spin resonance measurements of spin-labeled membranes of intact cells. Evidence has been obtained that liposomal lipids are either taken up by M14 cells or become incorporated in the cell membrane. The present data suggest the possibility that liposome treatments per se could be of potential value as a therapeutic approach, by increasing the effect of heat therapy.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1990

Roles of function, reminding, and variability in categorization by 3-month-old infants.

The roles of function, reminding, and exemplar variability in categorization of a physically dissimilar object were studied with 3-month-old infants trained to move a crib mobile by kicking. Performance on a transfer test with a motionless novel object provided evidence of categorization. In Experiments 1 and 2, infants, like adults, initially categorized novel objects on the basis of physical appearance, but only if trained with multiple exemplars, after delays of 1 and 7 days. In Experiment 3, prior knowledge of an object's functional properties overrode physical dissimilarity as the basis for categorization and enabled reminding of the classification response 2 weeks later. In Experiment 4, postevent contingency information overrode physical and functional properties as the basis for categorization. These findings indicate that expectations and goals influence infants' category decisions and raise the possibility that infants of 3 months respond by analogy.

Arousal↗
PubMed1990

Electrophysiological significance of QRS alternans in narrow QRS tachycardia.

To investigate the electrophysiological significance of QRS alternans during narrow QRS tachycardia, transesophageal atrial pacing and recording was performed in 24 patients with a history of paroxysmal supraventricular tachycardia. Standard electrocardiograms showed ventricular preexcitation in 15 patients and normal QRS pattern in nine patients. The ventriculoatrial interval during tachycardia, as defined by means of transesophageal electrogram, allowed tentative diagnosis of the tachycardia mechanism. A 12-lead ECG was recorded either during spontaneous or induced tachycardia, as well as during transesophageal atrial pacing at increasing rates. Electrical alternans occurred spontaneously in eight patients (33%, group A): five with accessory pathway reentry (mean VA: 136 +/- 43 msec), and three with AV nodal reentry (mean VA: 48.3 +/- 12 msec). Tachycardia rate ranged between 170 and 230 beats/min (mean 200.7 +/- 16). In two patients, alternation of the QRS occurred only in the presence of a heart rate exceeding 180 and 190 beats/min, respectively. The amplitude of QRS remained stable during tachycardia in 16 patients (67%, group B): 14 had accessory pathway reentry (mean VA: 137.5 +/- 32 msec), and two had AV nodal reentry (mean VA: 45 +/- 7 msec). In this group, the tachycardia rate ranged from 150 to 210 beats/min (mean 175 +/- 12). Incremental transesophageal atrial pacing up to rates equal to that of tachycardia was performed in five patients from group A and in five patients from group B. Electrical alternans could not be induced in both groups with pacing at progressively increasing rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Fulguration of the bundle of His. Description of 3 new cases].

With the purpose to call attention to the clinical utility of fulguration of the His bundle (a therapeutic procedure somewhat neglected in Italy) 3 new cases are presented. All patients had a long history of supraventricular tachyarrhythmias refractory to conventional treatment. Patients 1 and 2, in whom surgical correction of tetralogy of Fallot and mitral valve replacement, respectively, had been performed several years before, had chronic atrial tachycardia with congestive heart failure. Patient 3 suffered from persistent atrial flutter, in the absence of demonstrable organic heart disease. Three shocks of 320 J were necessary to induce complete AV block in patient 1 and 2. In patient 3, a single discharge (320 J) resulted in interruption of AV conduction. Twenty-four hours after the procedure, a rate-responsive ventricular pacemaker was implanted in all patients. The success of the procedure was confirmed 3 months later, during transitory pacemaker inhibition. Patients 1 and 3 exhibited atrial tachycardia and atrial flutter, respectively, but complete AV block was still present, with junctional escape rhythm at a rate of 40 and 45 b/min; in patient 2 atrial tachycardia with high degree AV block, and a mean ventricular rate of 75 b/min, were observed. Refinement of transcatheter ablative techniques is desirable. However, even in the present status, catheter ablation of the His bundle is an effective, low-risk procedure for patients with refractory supraventricular tachyarrhythmias.

Adult↗
PubMed1989

[Surgical cardiac risk in patients with heart diseases. I. Evaluation of the risk].

To evaluate the cardiac risk in patients undergoing noncardiac surgery, it has been identified by the multivariated analysis some major and independent correlates of fatal or life-threatening cardiac complications. The most important ones were the history of previous myocardial infarction in the preceding six months, clinical signs of congestive heart failure, third heart sound or jugular venous distention, and for some Authors instable angina class IV CCS. Other predictive factors of complications were premature ventricular and atrial contractions or ectopic rhythms within cardiac diseases, age over 70 years, intraperitoneal, intrathoracic, aortic or emergency operation, severe valvular aortic and mitral stenosis and poor general medical conditions. Stable angina, hypertension, hyperlipidemia and smoking habit were less important. The global evaluation of cardiac risk can be performed by multifactorial index subdividing the patients into four very different risk classes. This is obtained by scores assigned to each statistically significant factor.

Age Factors↗
PubMed1989

[Surgical cardiac risk in patients with heart diseases. II. Perioperative treatment].

An improvement can be obtained in the surgical prognosis of the cardiopathic by working on the main risk factors. Congestive decompensation must usually be treated with diuretics; digitalis in only indicated in certain cases. In patients with ischaemic cardiopathy, angina therapy should be continued during the perioperative period, replacing the oral route; in the postoperative period. ECG monitoring is advisable up to Day III-V. Valve defects should be assessed carefully, including haemodynamically (especially severe aortic stenosis) because correction of the defect may become a priority. In hypertrophic cardiomyopathy hypovolaemia and loss of sinus rhythm should be avoided. Valve prostheses involve particular problems represented by antibacterial prophylaxis and perioperative anti-coagulation. Congenital cyanogenic cardiopathies often require a lowering of the haematocrit and careful control of hypotension. Postoperative arrhythmias generally have medical causes and require control of the latter before possible antiarrhythmic therapy. The implantation of a temporary prophylactic pacemaker is rarely needed; for patients with definitive pacemakers, some precautions are needed for the use of the thermocautery. It is very important to deal with poor general medical conditions that might affect prognosis. Control of hypertension is less important than control of hypotension.

Heart Diseases↗
PubMed1989

[Transesophageal pacing in the diagnosis of accelerated atrioventricular conduction].

The term "enhanced atrioventricular nodal conduction" (EAVN) is used to indicate an electrophysiologic condition characterized by subnormal conduction delay with reduced decremental properties in the AV node, which can be responsible for rapid ventricular rates in the event of fast atrial rhythms. Although identification of such an entity usually requires definition of the AV conduction intervals, some authors have suggested that EAVN can be diagnosed, by means of atrial pacing only, when 1:1 conduction with narrow QRS complexes occurs during atrial pacing at rate higher than 200 bpm. The use of incremental transesophageal atrial pacing (TAP) as a noninvasive tool for identification of EAVN was investigated in 19 patients. Fifteen had a history of supraventricular tachyarrhythmias (11 Wolff-Parkinson-White syndrome; 2 Lown-Ganong-Levine syndrome; 1 intranodal AV reentry tachycardia; 1 sick sinus syndrome); 4 patients exhibited an electrocardiographic pattern of preexcitation without a history of tachyarrhythmias. Analysis of AV conduction at fast induced rates was hampered in 5 patients because of the easy occurrence of reciprocating tachycardia and/or atrial fibrillation during TAP, as well as because of the persistence of delta wave at cycle lengths (CL) shorter than 300 ms. Among the remaining patients, in 7 (50%, Group A), 1:1 AV conduction was present at pacing CL shorter than 300 ms. In 7 patients (50%, Group B), AV block occurred at pacing CL longer than 300 ms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗