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M Valentino

Publications and source records attributed to M Valentino.

At least 19 recordsLinked to original sources
PubMed2006

Effects of exposure to fluoro-edenite fibre pollution on the respiratory system: an in vivo model.

An increased standardised rate of mortality from pleural mesothelioma among the population of Biancavilla (Sicily, Italy) has been attributed to exposure to fluoro-edenite fibres. Our aim was to establish whether and how these fibres may induce pathological effects using an in vivo model. Lung tissue collected from 60 healthy sheep selected from six flocks habitually grazing near Biancavilla and from 10 control sheep was fixed formalin and paraffin-embedded; sections were stained with haematoxylin-eosin, Masson trichrome and Gomori argentic impregnation. Histochemical studies and immunohistochemical analysis for the localisation of TRAIL, DR5 and MMP13 were also performed. The lungs of exposed sheep exhibited fibrosis and loss of alveolar architecture with honeycombing of alveolar cavities. Fluoro-edenite fibres were detected close to the alveolar epithelium and interstitia. The parenchyma showed hyaline degeneration and strong PAS-positivity in the interstitium, proteoglycan alterations, reflecting a damaged basal membrane and an involvement of the interstitial matrix. MMP-13 was overexpressed, mainly in fibroblasts and epithelial cells, while positivity for TRAIL and DR5 was detected on alveolar surfaces and in the vascular stroma. The initial pathological event seems to involve first the alveoli and subsequently the interstitium, giving rise to classic honeycombing. The triggering event at the level of type I pneumocytes would damage the cytoplasmic membrane resulting in loss of cell elements and exposure of underlying capillaries, and eventually in a series of reactions including macrophage activation, possible release of growth factors and metaplasic reconstruction of lung alveoli. Immunopositivity for TRAIL and MMP-13 receptor suggests that apoptotic processes may also be activated by fluoro-edenite.

Air Pollutants↗
PubMed2003

Prediction of malignant infarction: perifocal neurochemical monitoring following prolonged MCA occlusion in cats.

Neurochemical monitoring in the ischemic core predicts malignancy in focal ischemia in cats. Since perifocal regions are more suitable for clinical microdialysis (MD) applications, we tested whether monitoring at such site predicts also malignancy.--Laser Doppler (LD) probes, pressure microsensors, and MD/HPLC measured cerebral blood flow (CBF), intracranial pressure (ICP), and extracellular glutamate (Glu), respectively. The middle cerebral artery was occluded (MCAO) for 3 hours followed by 6 hours reperfusion. Additionally, LD measured CBF in ischemic core.--MCAO reduced CBF in the core in all below 25% of control. In animals exhibiting malignancy (eye dilatation during reperfusion), MCAO decreased CBF in the perifocal site to around 35%. CBF primarily recovered following recirculation but decreased thereafter as ICP rose due to progressive edema formation. Glu increased concomitantly. In cats exhibiting a benign course, MCAO decreased CBF in the perifocal site to around 55%. Recirculation normalized CBF, and Glu did not increase. During MCAO, Glu differences between both groups were not significant.--Glu determinations in perifocal sites taken during MCAO do not predict fatal outcome. This contrasts with determinations in the core. After reperfusion, Glu elevation in perifocal sites may serve as a rather late predictor of malignancy.

Animals↗
PubMed2003

Identification of malignant brain edema after hemispheric stroke by PET-imaging and microdialysis.

Cerebral blood flow (CBF) and extent of irreversible tissue damage as well as the time course of extracellular concentration of amino acids, substrates of energy metabolism, and purine metabolites, intracranial pressure and tissue oxygen tension were assessed in 34 patients with large strokes covering more than 50% of the MCA territory. The results were compared to findings in the experimental model of transient (for 3 hours) MCA occlusion in cats. In the experimental model as well as in the clinical setting development of malignant brain infarcts (due to formation of space occupying brain edema) was predicted by the size of critically hypoperfused tissue and the volume of irreversibly damaged tissue. The course of malignant infarcts was characterized by progressive increase in concentrations of excitatory amino acids, lactate, pyruvate, glycerol, hypoxanthine and in intracranial pressure, while cerebral perfusion pressure and tissue oxygen tension decreased. These results clearly differentiate a malignant from a benign course of large hemispheric infarction. The methods can be used to identify patients at risk for formation of space occupying edema and to select patients who could benefit from invasive therapeutic strategies.

Amino Acids↗
PubMed2001

In vitro inhibition of thymulin production in mercury-exposed thymus of young mice.

Lymphocyte differentiation, maturation and peripheral functions are affected by the thymic protein hormone thymulin. Mercury at very low concentrations has been seen to impair some lymphocytic functions causing subclinical manifestations in exposed workers. The present study was performed to test in vitro the effect of mercury on the production kinetics of thymulin using cultures of whole thymuses from young mice. Exposure to mercury (10(-8) M and 10(-6) M) added to the cultures, reduced kinetic thymulin production at all time intervals considered (1, 2, 4, 5 and 6 h) as compared to kinetic thymulin production of thymuses from young control mice. After the first hour the inhibition is more evident at the highest mercury concentration. Thymulin production decreased by 70, 74, 82 and 86% and by 55, 66, 73 and 81% for mercury concentrations of 10(-6) M and 10(-8) M, respectively, after 2, 4, 5 and 6 h. Mercury toxic effect on thymulin kinetics may be directly exerted to thymulin synthesis in epithelial cells, although it is less dramatic than that of cycloheximide (CHX), known as a potent inhibitor of protein synthesis in such cells. The toxic effect of mercury on thymic endocrine activity might cause the subclinical effects on cell-mediated immunological status observed in mercury exposed workers.

Animals↗
PubMed2001

Monocyte-macrophage system and polymorphonuclear leukocytes in workers exposed to low levels of metallic mercury.

Our previous research (Soleo L, Vacca A, Vimercati L et al. Occup Environ Med 1997;54:437-442) showed a reduction in tumor necrosis factor-alpha (TNF-alpha) serum levels in workers with prolonged exposure to low doses of inorganic mercury, suggesting an in vivo functional defect of the monocyte-macrophage system. On this basis, here we wondered whether workers exposed to lower doses of metallic mercury displayed possible changes in the monocyte-macrophage system. In this particular cohort of workers, we also sought for the effects of the exposure on the polymorphonuclear leukocytes (PMNL) chemotaxis. The monocyte-macrophage system and the natural killer (NK) cells were examined in 19 exposed workers and in 25 unexposed workers, as the control group (controls). Specifically, the circulating monocyte-macrophage cells and their CD13, CD15 and CD33 subsets, serum cytokines (IL-8, GM-CSF and TNF-alpha) and the NK cells were analyzed. In seven exposed and seven controls randomly chosen workers the PMNL chemotaxis was also assessed. The selected indicator of mercury exposure were the levels of mercury in the urine (U-Hg), that was significantly higher in exposed workers than the controls (9.7 +/- 5.5 microg/l and 2.4 +/- 1.2 microg/l, respectively). None of the exposed workers had shown signs of either acute or chronic inorganic mercury toxicity or any form of hypersensitivity. Several immunological variables tested, monocyte-macrophage cells and their subsets, NK cells and serum cytokines overlapped between the exposed and the control workers. When the workers were considered as a whole (exposed plus controls), no correlation was found between current U-Hg and all immunological parameters. However, when exposed workers were studied separately, an inverse correlation was disclosed between cumulative U-Hg and cells (as percentage) expressing the CD13 (r = -0.599; P = 0.007) and CD15 (r = -0.614; P = 0.005) molecules, and NK cells (r = -0.455; P = 0.05). Moreover, a significant impairment in the PMNL chemotaxis (t = 3.70; P = 0.003) was observed in the exposed workers. The results of our study suggest that the exposure to very low levels of metallic mercury led to subtle impairment of circulating monocyte and NK cells (as percentages) according to the increase in U-Hg levels, as well as of the PMNL chemotactic function in this particular group of workers, even though they remain clinically asymptomatic. Therefore, we suggest that impairment of these parameters provide a sensitive indicator of metallic mercury and other chemical contaminants present in the environment.

Adult↗
PubMed2001

Elevation of extracellular glutamate in the final, ischemic stage of progressive epidural mass lesion in cats.

Epidural mass lesions may cause ischemia due to progressive intracranial hypertension. In order to investigate the impact of intracranial pressure on accumulation of neuroactive substances, we gradually raised intracranial pressure in five halothane anesthetized cats by inflation of an epidural balloon. We evaluated in the parietal cortex contralateral to the site of balloon inflation, alterations of extracellular glutamate and purine catabolites and of the lactate/pyruvate ratio in relation to changes of intracranial, cerebral perfusion and mean arterial blood pressure. In a complementary experiment, regional cerebral blood flow was assessed by sequential positron emission tomography. In this simplified mass lesion model, extracellular glutamate increased in all cats at a late, critical stage after tentorial herniation, when intracranial pressure had increased to more than 90 mm Hg, cerebral perfusion pressure had decreased below 40-50 mm Hg. Positron emission tomography assessments revealed that the ischemic threshold for glutamate accumulation was in the range of 15-20 mL/100 g/min. Purine catabolites and the lactate/pyruvate ratio increased somewhat earlier than glutamate, but also after reaching the critical, terminal stage. We conclude that in this model of progressive epidural compression, glutamate-mediated excitotoxic processes at sites remote from the initial focal lesion depend on processes such as delayed ischemia in combination with tentorial herniation and systemic hypotension. These processes seem to be initiated by a decrease of cerebral perfusion pressure below a threshold of 40-50 mm Hg.

Animals↗
PubMed2001

Tetanus in a central Italian region: scope for more effective prevention among unvaccinated agricultural workers.

In 1997, Italy had the highest number of tetanus cases in the European Union; cases in the Marches region were more numerous than in France or Germany. In a retrospective study of the patients infected in Marches in 1996-1999, subjects or relatives were interviewed to ascertain disease severity, infection mode, occupation and immunization state at the time of infection. There were 32 cases, 29 (90.6%) females and three (9.4%) males, mean age 74.65 years (SD 9.06). The raw annual incidence was 5.6 per million and raw annual mortality 0.5 (n = 3). Twenty-seven patients (84.4%) were agricultural workers and five (15.6%) housewives; 25 (78.2%) had never been vaccinated, two (6.2%) had been immunized several years earlier and five (15.6%) had received only the first dose of vaccine at least 15 years earlier. In Italy, tetanus vaccination is compulsory for agricultural workers. Occupational health physicians should monitor workers' tetanus immunization state during their periodic surveillance visits.

Adult↗
PubMed2001

Physician perceptions of a national formulary.

OBJECTIVE: To assess the perceptions of US Department of Veterans Affairs (VA) physicians regarding effects of a National Formulary (NF) on patient care, access to drugs, physician workload, and resident training approximately 1 year after it was implemented. STUDY DESIGN: Cross-sectional survey. METHODS: A questionnaire was sent to attending physicians working within the VA healthcare system. Participants included general internists (n = 2824), neurologists (n = 238), psychiatrists (n = 997), general surgeons (n = 429), and urologists (n = 152). The response rate was 45%. RESULTS: Most physicians (63%) thought that they could prescribe needed drugs; 65% agreed that patients could obtain needed nonformulary drugs. One third disagreed that access to prescription pharmaceuticals had increased; 29% stated the NF impinged on providing quality care to their own patients, and 21% thought it did so to patients from other VA facilities. Thirty eight percent of physicians perceived the NF to be more restrictive than private sector formularies; 16% thought that the NF diminished the ability to train residents for managed care. Forty percent thought that the NF added to workload. Generalists more often perceived that the NF improved their ability to provide care compared with neurologists (27% vs 18%, P = .046), psychiatrists (27% vs 22%, P = .027), and internal medicine subspecialists (27% vs 18%, P = .001). Physicians with more clinic time were more likely to perceive that the NF increased workload. CONCLUSION: Although differences of opinions among physicians were noted, most responding VA physicians did not perceive that the NF adversely affected patient care, access to pharmaceuticals, physician workload, or resident training.

Attitude of Health Personnel↗
PubMed2000

In vitro cleavage by asbestos fibers of the fifth component of human complement through free-radical generation and kallikrein activation.

Chrysotile and crocidolite fibers incubated in normal human plasma (NHP) generated from the C5 component of complement C5a-type fragments that stimulated polymorphonuclear leukocyte (PMN) chemotaxis. Absorption of NHP with antiserum against C5a totally abolished neutrophil chemotactic activity. Asbestos fibers also produced C5a small peptides in the presence of ethylene glycol bis(beta-aminoethyl ether) N,N,N'N'-tetraacetic acid (EGTA) but not ethylene diamine tetraacetic acid (EDTA). Activation of C5 was significantly inhibited when asbestos fibers were pretreated with iron chelators such as sodium dithionite (DTN), deferoxamine (DFX), or ascorbate (AA). Concentration-related inhibition of C5 activation was also observed when asbestos fibers were added concurrently to plasma in the presence of DFX, 1,3-dimethyl-2-thiourea (DMTU), a strong hydroxyl scavenger, or aprotinin (APR), a specific protease inhibitor. Further, chrysotile and crocidolite significantly increased plasma kallikrein activity. Data demonstrate that asbestos-induced C5 activation plays a role in inflammatory reactions characteristic of asbestosis through mechanisms involving iron ions, hydroxyl radicals, and oxidized C5-ike fragments. The ferrous ions present at the asbestos fiber surface trigger this activation and catalyze, via Fenton reaction, the production of hydroxyl radicals, which in turn convert native C5 to an oxidized C5-like form. This product is then cleaved by kallikrein, activated by the same asbestos fibers, yielding an oxidized C5a with the same functional properties as C5a.

Adult↗
PubMed2000

Factors influencing psychological stress levels of Italian peacekeepers in Bosnia.

OBJECTIVE: The present study evaluated the factors that contribute to stress and the psychological difficulties of the Italian military component of the United Nations Mission in Bosnia and Herzegovina. This group was compared with a homogeneous group stationed in Italy. METHODS: A cross-sectional study was performed in two groups of career military personnel: 452 subjects who were stationed in Bosnia as peacekeepers and 166 who were stationed in Italy. All subjects completed two multiple-choice questionnaires (a stress self-evaluation test and a socioeconomic questionnaire) during various periods of duty. RESULTS: The responses to the stress self-evaluation test indicated that the peacekeepers did not show a statistically significant increase in stress. Those who were affected by stress, though, indicated that the level was high. The principal variables that were associated with a greater level of stress were length of the mission, lack of recreational or athletic activities during the mission, more than three family members, and unemployment before enrollment. CONCLUSIONS: Peacekeepers come from an economically poor environment, have large families, and usually have a history of unemployment. Along with these preenrollment risk factors, the effective time spent in recreational activities and the length of the mission also influence stress levels. Individual and group techniques for stress management should be implemented.

Adult↗
PubMed1999

[Analysis of local electrograms and characteristics of the ablation procedure in left-sided accessory pathways that required five or more pulses of radiofrequency].

INTRODUCTION AND OBJECTIVES: Radiofrequency ablation of left sided accessory pathways requires multiple pulses in some patients due to different factors such as inadequate mapping, inappropriate tissue electrode contact and particular anatomic factors. However these characteristics have not been specifically analyzed. METHODS: We have studied a prospective ablative series of 65 consecutive patients with left-sided pathways submitted to radiofrequency ablation by a simplified technique. In every application point, we analyzed the electrogram features, application point, impedance, potency and temperature. RESULTS: 52 patients (80%) required less than 5 radiofrequency pulses (group A) and 13 (20%) required > or = than 5 pulses (group B). The presence of a suggestive potential accessory pathway in local electrogram was similar in both groups and there were no differences in the local A-V or V-A intervals. However, in patients with pre-excitation the Delta-V interval was shorter in group A than in group B (8 ms vs 15 ms; p < 0.001). Furthermore, the impedance observed from the ablation point in group A was lower (108 +/- 12 vs 121 +/- 22 ohms; p < 0.001), and the maximum watts required to reach the predetermined temperature was higher in group A (42 +/- 16 vs 31 +/- 18 watts; p < 0.001). Final success of the procedure was 100%. CONCLUSIONS: Patients requiring more than 5 radiofrequency pulses had electrograms and tissue contact equal or better than those requiring less than 5 pulses. This suggests that difficulties encountered in some procedures can be due to anatomical factors rather than inaccurate mapping or insufficient tissue contact.

Adolescent↗
PubMed1999

Arrhythmia recurrence in patients with a healed myocardial infarction who received an implantable defibrillator: analysis according to the clinical presentation.

OBJECTIVES: The purpose of this study was to analyze the type of arrhythmia recurrence, based on stored electrograms, in patients with a healed myocardial infarction (MI) who received an implantable defibrillator. BACKGROUND: Previous studies suggest that patients presenting with cardiac arrest (CA) tend to recur as ventricular fibrillation (VF), whereas those suffering sustained monomorphic ventricular tachycardia (SMVT) tend to recur as SMVT. However, these data have not been confirmed in a homogeneous population of patients with MI. METHODS: A total of 88 patients was divided into three groups according to their clinical presentation: SMVT (n = 57), CA (n = 16) or syncope (n = 15). RESULTS: There were no significant differences in clinical characteristics among groups. In the electrophysiologic study SMVT was induced in 93%, 94% and 80% of patients, respectively (p = NS). During the follow-up period, 52% of patients presented a total of 671 episodes of ventricular arrhythmia treated by the defibrillator. All recurrences were as SMVT except for one VF. There were 610 episodes of SMVT treated with antitachycardia pacing, with an effectiveness of 96%. A total of 61 episodes was treated initially with cardioversion. No differences in the probability of recurrence were observed among groups, although the statistical power was low (50%). CONCLUSIONS: In patients with an old infarction and malignant ventricular arrhythmias, the majority of recurrences are due to SMVT independently of the clinical presentation (SMVT, CA or syncope) or the induced arrhythmia at the electrophysiologic study. The programming of an antitachycardia zone seems to be appropriate also for patients who present with CA or syncope.

Aged↗
PubMed1999

Time to first shock in implantable cardioverter defibrillator (ICD) patients with Chagas cardiomyopathy.

UNLABELLED: The time to first ICD shock has been extensively studied in patients with coronary artery disease (CAD). However, there are no published data on ICD shocks in patients with Chagas cardiomyopathy (ChC). The occurrence of the first appropriate ICD shock during the first 6 months of follow-up in 20 patients with ChC (group 1) and 35 CAD patients (group 2) was analyzed retrospectively. All patients had received a third-generation pectoral ICD for ventricular tachycardia or fibrillation (VT/VF). Indications for ICD implantation were refractoriness to drug therapy or noninducibility of VT/VF at EPS in cardiac arrest survivors. RESULTS: The mean age, left ventricular ejection fraction (LVEF), and sex in groups I and II were 57.4 +/- 7 years versus 64 +/- 9 (P < 0.01), 30.9% +/- 10% versus 32.9% +/- 10% (P = NS), and 10 men versus 31 women (P < 0.005), respectively. Six months after ICD implantation, 85% (17/20) group I patients received appropriate ICD shocks versus 51% (18/35) in group 2, a statistically significant difference (P < 0.02, RR: 1.65, OR: 5.35). CONCLUSIONS: The incidence of appropriate ICD shocks within the first 6 months postimplantation was significantly higher in ChC patients than in CAD patients. ChC patients were younger and more often women than CAD patients.

Adult↗
PubMed1999

[Arrhythmia recurrence in patients with an old myocardial infarct treated by implantable defibrillator: an analysis according to the initial clinical presentation].

INTRODUCTION AND OBJECTIVES: The importance of the clinical presentation in the frequency and type of recurrences of ventricular arrhythmias in patients that received an automatic implantable defibrillator is not well known. The purpose of this study was to analyze the frequency and type of recurrences in patients with an old myocardial infarction that received an automatic implantable defibrillator with electrogram recording. METHODS AND RESULTS: We analyzed 100 patients classified in 3 groups according to their clinical presentation: Sustained Monomorphic Ventricular Tachycardia (VT Group n = 65), Cardiac Arrest (CA Group = 19), and Syncope (Syncope Group n = 16). There were no significant differences in the clinical variables among the different groups, nor in the inducibility of arrhythmia at the electrophysiologic study. In a follow-up 27 +/- 14 months, 54% of patients presented at last one episode of sustained ventricular arrhythmia. All recurrences except one were as sustained monomorphic ventricular tachycardia (776 episodes). 81% of episodes of sustained monomorphic ventricular tachycardia (630) were treated with antitachycardia pacing with an effectiveness of 89%. There were no differences in the probability of arrhythmic recurrence among groups but death probability was higher in the ventricular fibrillation group at 36 follow-up months (38% vs 7% and 12% in the sustained monomorphic ventricular tachycardia and syncope groups respectively, p = 0.0113). CONCLUSIONS: In the patients with an old myocardial infarction and malignant ventricular arrhythmias, most of recurrences are due to sustained monomorphic ventricular tachycardia independently of the clinical presentation. The antitachycardia pacing is not only effective in patients with documented sustained monomorphic ventricular tachycardia but also in those that are presented as cardiac arrest or syncope.

Aged↗
PubMed1998

Wollastonite fibers in vitro generate reactive oxygen species able to lyse erythrocytes and activate the complement alternate pathway.

Wollastonite fibers were tested in vitro for their ability to produce reactive oxygen species (ROS) with two different systems: a cell-free reactive mixture containing deoxyribose and a polymorphonuclear leukocyte suspension. After adding the fibers, we measured the thiobarbituric acid-reactive substances produced by deoxyribose degradation and luminol-enhanced chemiluminescence, respectively. Compared with asbestos, wollastonite fibers produced higher ROS levels both in the PMN suspensions and in the cell-free reactive mixtures. A large amount of these ROS were not hydroxyl radicals. Indeed we obtained remarkable differences in ROS generation between unground and ground wollastonite fibers and negative results with fibers modified with ferric chloride and dithionite. In addition, ROS generation was partially inhibited (by 46-54%) in the reactions performed in the presence of 1,3-dimethyl-2-thiourea (DMTU), a strong hydroxyl radical scavenger. Wollastonite fibers were also analyzed for their ability to lyse erythrocytes and activate complement. Hemolytic potency was about twice that of chrysotile and half that of crocidolite. The levels of complement activation (via the alternate pathway) were about four-fifths of those measured in zymosan-activated plasma (a typical stimulus used to activate the alternate pathway), equal to those obtained with crocidolite, and two-thirds of those found with chrysotile. The addition of DMTU markedly reduced both these activities. Since asbestos fiber toxicity is mainly due to hydroxyl radical generation, our results indicate that wollastonite fibers are probably less toxic than asbestos fibers.

Adult↗
PubMed1998

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

OBJECTIVES: This study sought to determine the long-term follow-up, safety and efficacy of radiofrequency catheter ablation in patients with the permanent form of junctional reciprocating tachycardia. We assessed the reversibility of tachycardia-related left ventricular dysfunction and we detailed the location and electrophysiologic characteristics of these atrioventricular decremental pathways. BACKGROUND: Permanent junctional reciprocating tachycardia is an infrequent form on reciprocating tachycardia, commonly incessant and usually drug-refractory. The electrocardiographic hallmarks include an RP interval > PR with inverted P waves in leads II, III, aVF and V3-V6. During tachycardia, retrograde ventriculo-atrial conduction occurs over an accessory pathway with decremental conduction properties, located predominantly in the posteroseptal zone. It is known that long lasting and incessant tachycardia may result in tachycardia-related severe ventricular dysfunction, the so called tachycardiomyopathy. PATIENTS AND METHODS: We included 24 patients (9 males, 15 females; mean age 42 +/- 22 years) with the diagnosis of permanent junctional reciprocating tachycardia at electrophysiologic study. Six patients had tachycardia-related left ventricular dysfunction. Radiofrequency energy was delivered at the site of earliest retrograde atrial activation during reciprocating tachycardia (n = 22) or ventricular pacing (n = 2). All patients were followed at the outpatient clinic and serial echocardiograms were performed in those who presented depressed left ventricular function. RESULTS: Radiofrequency catheter ablation was performed in 24 decremental accessory pathways. Earliest retrograde atrial activation was right posteroseptal in 22 patients (92%), right midseptal in 1 (4%) and right posterolateral in 1 (4%). Twenty-three accessory pathways were successfully ablated with a mean of 5 +/- 3 (median, 4) radiofrequency applications of a mean duration of 48 +/- 13 s. Only the midseptal accessory pathway could not be ablated. After a mean follow-up of 21 +/- 16 months (median, 15; range 2 to 64) 22 patients remain asymptomatic. There were recurrences in 4 patients after the initial successful ablation (three during the first month and one during the second month after the procedure), two were ablated in a second ablation procedure, one patient required a third procedure and one required a fourth. All patients with left ventricular dysfunction experienced an improvement after ablation. Mean preablation left ventricular ejection fraction in patients with tachycardiomyopathy was 28 +/- 6% (median, 27) and raised to 51 +/- 16% (median, 47) after ablation (p < 0.02). CONCLUSIONS: Our study supports the concept that radiofrequency catheter ablation is a safe and useful treatment for patients with permanent junctional reciprocating tachycardia. Radiofrequency current should be the treatment of choice in these patients because this arrhythmia is usually drug-refractory. The majority of accessory pathways with decremental conduction properties are localized in the posteroseptal zone. Cessation of the arrhythmia after successful ablation results in recovery of left ventricular dysfunction.

Adolescent↗
PubMed1998

[Hemodynamic deterioration in patients submitted to ablation of the atrioventricular node].

INTRODUCTION: Radiofrequency ablation of the atrioventricular conduction system has become an established therapy for patients with drug-refractory atrial fibrillation. We observed 14 patients with hemodynamic deterioration related to worsening of mitral regurgitation after the procedure. PATIENTS AND METHODS: We retrospectively evaluated 256 consecutive patients with drug-refractory atrial fibrillation referred for radiofrequency ablation of the AV node and implantation of a pacemaker. Because we found hemodynamic deterioration related to worsening mitral regurgitation, we compared the clinical history, electrophysiologic and echocardiographic data from the patients with hemodynamic deterioration and worsening mitral regurgitation (group A) with those without hemodynamic deterioration (group B). RESULTS: Fourteen out of 256 patients (group A) undergoing ablation of the atrioventricular conduction system deteriorated with acute pulmonary edema (3 patients) or congestive heart failure (11 patients) at a mean of 6 weeks after the ablation procedure. Four of these patients were referred for mitral valve surgery. The length of the procedure and the number of applications during ablation were similar in both groups. Compared with group B patients, group A patients had significantly higher left ventricular end-diastolic diameters (64 +/- 6 mm vs 56 +/- 9 mm; p < 0.05) at baseline despite similar left ventricular end-systolic diameters, fractional shortening and grade of mitral regurgitation (1.15 +/- 1.05 vs 1.11 +/- 0.97). Moreover, whereas no change was observed in left ventricular end-diastolic diameter, left ventricular end-systolic diameter, fractional shortening and grade of mitral regurgitation in group B patients after ablation, group A patients experienced a significant increase in left ventricular end-diastolic diameter (64 +/- 6 mm vs 72 +/- 9 mm; p < 0.01) and grade of mitral regurgitation (1.15 +/- 1.05 vs 2.90 +/- 1.15; p < 0.01). In patients operated on no ablation related structural damage to the mitral valve apparatus could be detected. The worsening of the mitral regurgitation was related to dilation of the mitral valve annulus. CONCLUSIONS: Hemodynamic deterioration together with progression of mitral regurgitation is a potential complication of ablation of the atrioventricular conduction system.

Adult↗