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Biomedical subjects

M Valentino

Publications and source records attributed to M Valentino.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Patients with structural heart disease, syncope of unknown etiology and inducible ventricular arrhythmias treated with implantable defibrillators].

OBJECTIVES: This study evaluates the hypothesis that in patients with syncope of unknown origin and heart anomalies, inducible ventricular arrhythmias are specific arrhythmias and therefore should be treated as such. BACKGROUND: Although syncope is a frequent clinical entity, the evaluation and treatment of patients with syncope without a clear etiology still remains undefined. Many patients with syncope of undetermined origin undergo invasive electrophysiologic evaluation. Abnormalities of the sinus node, prolongation of conduction times or inducible arrhythmias found during these evaluations are usually assumed to be the cause of syncope, and are consequently treated. However, whether tachyarrhythmias are truly the cause of syncope, and whether treatment of these tachyarrhythmias can prevent recurrent syncope and arrhythmic death, is unknown. PATIENTS AND METHODS: An electrophysiological study was performed on 160 patients with structural heart disease and syncope of unknown origin. In 23 out of the 160 patients (16%), programmed electrical stimulation induced sustained ventricular arrhythmias. In 18 out of the 23 patients an automatic defibrillator was implanted and they form the study group. RESULTS: In these 18 patients, programmed ventricular stimulation induced sustained monomorphic ventricular tachycardia in 12, sustained polymorphic ventricular tachycardia in 2 and ventricular fibrillation in 4. During a mean follow-up of 14 months, 9 patients received 81 appropriate therapies from the device (53 because of ventricular tachycardia and 23 because of ventricular fibrillation). The probability of appropriate therapy was 100% at 1 year follow-up. There were no episodes of sudden death and 1 patient died of congestive heart failure. CONCLUSIONS: In patients with syncope of undetermined origin, heart disease and inducible ventricular tachyarrhythmias treated with a implantable cardioverter defibrillator, there is a high incidence of appropriate therapies. Our results support the practice of using implantable cardioverter defibrillators in patients with syncope of unknown origin, heart disease and inducible ventricular arrhythmias.

Adolescent↗
PubMed1998

[Radiofrequency ablation of multiple atrioventricular accessory pathways in a patient with syncope, atrial fibrillation and fasciculoventricular fibers].

Multiple accessory pathways in patients with the Wolff-Parkinson-White syndrome are infrequent and are associated with a higher risk of ventricular fibrillation. We present an exceptional case of a patient with four accessory pathways with anterograde conduction and a fasciculo-ventricular fiber in whom we performed a radiofrequency ablation. A 20 year old healthy male patient was seen at the emergency room after suffering syncope. The electrocardiogram showed atrial fibrillation with wide QRS complex suggestive of preexcitation. The electrophysiologic study demonstrated the presence of four atrio-ventricular accessory pathways with antegrade conduction (left lateral, right posteroseptal, right midseptal and right posterolateral). After ablation of the fourth accessory pathway, the electrocardiogram showed a persistent delta wave with a short HV interval. Atrial stimulation demonstrated decremental conduction, progressive lengthening of the AH interval and no modification in the HV interval nor in the preexcitation pattern, suggestive of the presence of a fasciculo-ventricular fiber. This exceptional case report is demonstrative of the complexity of the Wolff-Parkinson-White syndrome, and the feasibility and efficacy of radiofrequency catheter ablation in a single procedure.

Adult↗
PubMed1998

Hypertrophic cardiomyopathy: role of the implantable cardioverter-defibrillator.

OBJECTIVES: We report the occurrence of cardiac events during long-term follow-up in patients with hypertrophic cardiomyopathy (HCM) after cardioverter-defibrillator implantation. BACKGROUND: The identification of patients at high risk for sudden death and the prevention of recurrence of sudden death in HCM represents a difficult problem. METHODS: We retrospectively analyzed the occurrence of cardiac events during follow-up of 13 patients with HCM who received an implantable cardioverter-defibrillator (ICD) because of aborted sudden death (n = 10) or sustained ventricular tachycardia (n = 3) (group I). Findings were compared with those in 215 patients with an ICD and other structural heart disease or idiopathic ventricular fibrillation (group II). RESULTS: After a mean (+/-SD) follow-up period of 26+/-18 months, 2 of 13 patients in group I received appropriate shocks. The calculated cumulative incidence of shocks was 21% in group I and 66% in group II after 40 months (p < 0.05). We observed a low incidence of recurrence of ventricular tachycardia/fibrillation during follow-up in patients with HCM. No deaths occurred. CONCLUSIONS: Our data suggest that ventricular tachyarrhythmias may not always be the primary mechanism of syncope and sudden death in patients with HCM. The ICD seems to have a less important impact on prognosis in patients with HCM than in patients with other etiologies of aborted sudden death.

Adult↗
PubMed1998

Long-term follow-up in patients with the permanent form of junctional reciprocating tachycardia treated with radiofrequency ablation.

This study sought to determine the long-term follow-up, safety, and efficacy of radiofrequency catheter ablation of patients with the permanent form of junctional reciprocating tachycardia (PJRT). We assessed the reversibility of tachycardia induced LV dysfunction and we detailed the location and electrophysiological characteristics of these retrograde atrioventricular decremental pathways. PJRT is an infrequent form of reciprocating tachycardia, commonly incessant, and usually drug refractory. The ECG hallmarks include an RP interval > PR with inverted P waves in leads II, III, a VF, and V3-V6. During tachycardia, retrograde VA conduction occurs over an accessory pathway with slow and decremental conduction properties, located predominantly in the posteroseptal zone. It is known that long-lasting and incessant tachycardia may result in tachycardia induced severe ventricular dysfunction. We included 36 patients (13 men, 23 women, mean +/- SD, aged 44 +/- 22 years) with the diagnosis of PJRT. Seven patients had tachycardia induced left ventricular dysfunction. Radiofrequency energy was delivered at the site of earliest retrograde atrial activation during ventricular pacing or during reciprocating tachycardia. All patients were followed at the outpatient clinic and serial echocardiograms were performed in those who presented with depressed LV function. Radiofrequency ablation was performed in 36 decremental accessory pathways. Earliest retrograde atrial activation was right posteroseptal in 32 patients (88%), right mid-septal in 2 (6%), right posterolateral in 1 (3%), and left anterolateral in 1 (3%). Thirty-five accessory pathways were successfully ablated with a mean of 5 +/- 3 applications. A mid-septal accessory pathway could not be ablated. After a mean follow-up of 21 +/- 16 months (range 1-64) 34 patients are asymptomatic. There were recurrences in 8 patients after the initial successful ablation (mean of 1.2 months), 5 were ablated in a second ablation procedure, 2 patients required a third procedure, and 1 patient required four ablation sessions. All patients with LV dysfunction experienced a remarkable improvement after ablation. Mean preablation LV ejection fraction in patients with tachycardiomyopathy was 28% +/- 6% and rose to 51% +/- 16% after ablation (P < 0.02). Our study supports the concept that radiofrequency catheter ablation is a safe and effective treatment for patients with PJRT. Radiofrequency ablation should be the treatment of choice in these patients because this arrhythmia is usually drug refractory. The majority of accessory pathways are located in the posteroseptal zone. Cessation of the arrhythmia after successful ablation results in recovery of LV dysfunction.

Adolescent↗
PubMed1998

Enhanced detection criteria in implantable defibrillators.

INTRODUCTION: Enhanced detection criteria in third-generation implantable defibrillators have been implemented to avoid inappropriate therapy of fast supraventricular arrhythmias. We prospectively analyzed the use of these criteria in patients with an implantable defibrillator with electrogram storing capability. METHODS AND RESULTS: In 82 consecutive patients with a Guidant-CPI implantable defibrillator, sudden onset > 9% and stability < 40 msec were systematically programmed in zone 1 of therapy together with a sustained rate duration security mechanism. All detected tachycardia episodes were analyzed. The study population consisted of 59 patients who had at least one episode of tachycardia detected in zone 1 during follow-up. The tachycardia rate in zone 1 never exceeded 210 beats/min. Twenty patients had no episodes during follow-up, and three patients had episodes detected exclusively in zone 2 of therapy. Supraventricular arrhythmias were detected frequently in the ventricular tachycardia zone (193 of 690 tachycardia episodes in 23 of 59 patients). Use of sudden onset was very effective in detecting sinus tachycardias (65 of 67 episodes), and stability was very useful in detecting atrial fibrillation (31 of 32 episodes). However, sensitivity in detecting ventricular tachycardia was only 90% (451 of 497 episodes). Application of the sustained rate duration criterion allowed appropriate treatment of all ventricular tachycardia episodes, increasing sensitivity to 100%; however, specificity in appropriate nontreatment of supraventricular decreased from 96% to 83%. Subsequent analysis of different algorithms applied to our data showed that sudden onset > 9% and stability < 40 msec was the algorithm with the best specificity and sensitivity. CONCLUSION: Programming sudden onset and stability detection criteria with a sustained rate duration safety net for triggering tachycardia therapy results in appropriate device management in most patients with supraventricular and slow (< 210 beats/min) ventricular tachycardias.

Algorithms↗
PubMed1997

[Histopathologic changes of cancer of the rectum after neoadjuvant radio-chemotherapy. Anatomo-radiologic correlation and prognostic implications].

The histopathologic study of 24 specimens of radiated rectal cancers suggested new histologic criteria to define tumor regression after neo-adjuvant therapy. Better than traditional UICC staging system (pTNM), such criteria have identified those patients at higher risk of failure. Moreover, the study has confirmed the known difficulties of imaging studies in assuring an accurate staging of radiated rectal cancer before surgery.

Adult↗
PubMed1997

[Tilt test for the evaluation of syncope of unknown origin].

UNLABELLED: The aim of this study was to evaluate the usefulness of head up tilt testing in patients with syncope of unknown origin. Between January 1994 and September 1995, 93 patients were referred for tilt table assessment due to recurrent syncope of uncertain etiology. There were 42 men (mean age 59 years). Thirty healthy volunteers served as a control group. The specific protocol used involved an initial period of supine rest for 15'. Baseline blood pressure (BP) and heart rate (HR) were recorded. This was followed by a tilt to 80 degrees for 30', BP and HR were measured every minute during the procedure. The test was considered positive when symptoms appeared associated with one of the following responses: systolic BP decreased more than 30 mmHg (vasodepressor), bradicardia or asystolia for up to 3" (cardioinhibitory) or mixed. RESULTS: The tilt test was positive in 31 of 93 patients (33%). Seventeen patients (55%) had a vasodepressor response, 3 patients (9%) a cardioinhibitory response and 11 patients (36%) mixed responses. The clinical manifestations were 62% near syncope, 19% syncope and the other patients presented dypsnea or dizziness. The symptoms disappeared promptly after adopting the supine position. None of the 30 healthy volunteers developed symptoms. We conclude that head up tilt test is a safe and effective method for identifying a neurocardiogenic origin in a syncope of uncertain etiology.

Adolescent↗
PubMed1995

In vitro biological effects of clay minerals advised as substitutes for asbestos.

We studied one sample of commercial sepiolite and two samples of commercial vermiculite--clay minerals proposed as replacements for asbestos--and tested in vitro their abilities to activate complement, to lyse erythrocytes, and to elicit the production of reactive oxygen species (ROS) with human polymorphonuclear leukocytes (PMN) or bovine alveolar macrophages (AM); their behavior was compared with that of asbestos fibers obtained from the Union International Contra Cancer (UICC) as reference standards, as well as with kaolinite and illite, main members of the clay mineral family. Since in short-term in vitro tests the biological activity of mineral particles seems especially related to the active sites on their surface, we first measured the specific surface area of each mineral. Sepiolite was unreactive in two of the three tests we used (complement activation and ROS production) and able to lyse a minimal percentage of red blood cells. Vermiculite was shown to be incapable of activating complement, to have a moderate hemolytic activity and a high ability to elicite ROS production, although lower than that of chrysotile. Sepiolite, therefore, might be of more interest than vermiculite, given the low level of biological effects detected during the tests used to compare both clay minerals with asbestos fibres. The ROS production does not seem to require phagocytosis. A high ROS production was observed with kaolinite: this result casts doubt on the ability of pathogenic mineral dusts in vitro to induce a greater release of ROS than nonpathogenic mineral dusts.

Acridines↗
PubMed1994

Chemotactic activity of human polymorphonuclear leukocytes and industrial xenobiotics: a brief review.

This review deals with some of our contributions to the use of chemotaxis, as a tool in evaluating effects of industrial xenobiotics on PMN, either in vitro or ex vivo. In vitro experiments have shown that lead, arsenic, styrene and 2,5-hexanedione, a major neurotoxicant metabolite of n-hexane, reduce chemotaxis. The most important results of ex vivo experiments have confirmed those obtained in vitro with styrene and 2,5-hexanedione: a significant reduction of chemotaxis was indeed observed in PMN harvested from workers exposed to low levels of n-hexane or styrene who did not show any sign of biochemical or clinical alteration. After 3 weeks under non-exposed conditions, the chemotactic indexes were markedly increased in most of the workers which were exposed to styrene and in all the workers exposed to n-hexane, all of whom have shown a reduced chemotaxis at the first blood sampling. Moreover chemotaxis was found to be significantly reduced at relative low levels of lead: results of the in vitro and ex vivo experiments show a comparable ranking of midpoint inhibition concentrations. We are only at the dawn of the understanding of the relation between occupational xenobiotics and PMN chemotaxis. This research area is still promising for the future, since PMN chemotaxis seems to be adequate and it must therefore enter in well-defined study protocols for investigating the potential immunotoxicity of occupational chemicals to which humans are exposed at low levels.

Chemotaxis, Leukocyte↗
PubMed1994

Latex-induced asthma in four healthcare workers in a regional hospital.

Hypersensitivity to latex gloves has often been reported in patients who have undergone surgical treatment. Recent reports suggest that latex antigens can produce cutaneous and respiratory symptoms in workers occupationally exposed to latex. Four such cases of healthcare workers who were sensitized through exposure to latex have been observed. Two of these workers presented dermatitis as well as work-related respiratory symptoms, while the others only showed symptoms suggesting occupational asthma. The subjects were diagnosed as having latex hypersensitivity after skin prick-testing, and the immunoglobulin E serum level against latex gave positive results. In addition, changes in methacholine responsiveness also took place. In one case, an occupational exposure test was carried out which resulted in a 24% drop in the FEV1 value after 25 min of inhalation exposure. At least one year after the diagnosis, two nurses (subjects A and D) who had been removed completely from latex exposure experienced no further latex-induced symptoms. The other workers, who have continued working in the same laboratories using vinyl gloves, now display less severe symptoms but require regular anti-allergy treatment.

Adult↗
PubMed1994

Human polymorphonuclear leukocyte chemotaxis as a tool in detecting biological early effects in workers occupationally exposed to low levels of n-hexane.

Human polymorphonuclear leukocytes (PMN) were chosen to measure two cellular end points--chemotaxis and respiratory burst--and to verify whether they could function as biomarkers of early effect in detecting occupational exposure to n-hexane of apparently healthy shoe workers, without any electroneuromyographic (ENMG) abnormality. Chemotaxis, but not respiratory burst, was found to be impaired. A negative linear correlation between chemotaxis of PMN of those workers that had been exposed to n-hexane versus 2,5-hexanedione (2,5-HD) urinary concentrations were found. This negative trend is consistent with our previous in vitro experimental findings: it was observed that the progressive addition of 2,5-HD to PMN suspensions inhibited chemotaxis in a dose-dependent mode, while chemiluminescence was not modified. Now we have confirmed in vivo that chemotaxis is more sensitive than the respiratory burst response to 2,5-HD. Such results justify the interest in the behaviour of PMN harvested from workers exposed to n-hexane. Since significant inhibition of chemotactic activity was observed in some workers whose urinary 2,5-HD levels were lower than 5 mg l-1, which is the biological exposure index suggested by ACGIH, this study suggests that PMN chemotaxis may be proposed as a useful biomarker in detecting occupational exposure to low level of n-hexane.

Adolescent↗
PubMed1991

Effects of lead on polymorphonuclear leukocyte (PMN) functions in occupationally exposed workers.

Previous in vitro experiments have shown that lead can inhibit PMN chemotaxis, phagocytosis and superoxide formation. Moreover, we have observed an inhibition of PMN chemotaxis in workers occupationally exposed to lead with a mean blood lead concentration of 3.06 mumol/l. The present study was carried out to evaluate locomotion and luminol assisted chemiluminescence (CL) of polymorphonuclear leukocytes (PMN) harvested from ten lead occupationally exposed workers with blood lead concentrations of 1.59 mumol/l (SD 0.27 mumol/l). Since lipids affect PMN activity and lipid composition is modified in erythrocytes of lead workers, PMN lipids were also studied. Ten healthy male subjects of the same age were taken as controls. Chemotaxis, i.e. locomotion stimulated through a specific membrane receptor, was impaired in the PMN of lead workers, but random migration, i.e. unstimulated cell locomotion, and respiratory burst were both unmodified. Cholesterol and phospholipids were not changed, but the percentage of arachidonic acid was significantly increased. The release of LTB4, generated by the oxidative metabolism of arachidonic acid, was increased. CL, which detects reactive oxygen species (ROS), was unmodified, but this lack of change could be the result of an increase in ROS, due to the augmentated percentage of arachidonic acid, and of a decrease in ROS, due to a direct inhibitory effect of lead on ROS generation. On the basis of the results from these ex vivo experiments, the conclusion that chemotaxis is the PMN function primarily affected by lead was confirmed. PMN are considered to be one of the first cellular targets for the action of lead; low exposure to lead modifies their activity and mainly modifies chemotaxis and LTB4 production.

Adult↗