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Biomedical subjects

R Rabinovich

Publications and source records attributed to R Rabinovich.

16 recordsLinked to original sources
PubMed2002

Fluticasone propionate attenuates platelet-activating factor-induced gas exchange defects in mild asthma.

Inhaled glucocorticosteroids may reduce airway mucosal oedema in acute asthma. Inhaled platelet-activating factor (PAF) provokes pulmonary gas exchange disturbances, similar to those shown in severe asthma, which may be due to increased airway plasma leakage. This randomized, double-blind, placebo-controlled, crossover study investigated the effects of high doses of inhaled fluticasone propionate (FP) in 12 patients with mild asthma before and after PAF inhalation. Patients were studied before and 12 h after inhaling FP (6 mg) or placebo (P), and then at 5, 15 and 45 min after PAF challenge. Compared with vehicle, FP inhaled before PAF improved forced expiratory volume in one second and respiratory system resistance (Rrs), increased peripheral blood neutrophils and reduced eosinophil counts. After PAF, FP enhanced transient neutropenia at 5 min and facilitated the recovery of oxygen tension in arterial blood (FP: 93+/-4 mmHg; P: 83+/-4 mmHg) at 45 min, without influencing the increases in Rrs. In conclusion, the improvement of platelet-activated factor-induced oxygen tension in arterial blood disturbances after fluticasone proprionate suggests that inhaled glucocorticosteroids may possess vasoconstrictor properties in the pulmonary circulation.

Administration, Inhalation↗
PubMed2002

Physiological responses to the 6-min walk test in patients with chronic obstructive pulmonary disease.

The 6-min walking test (6MWT) is frequently used to assess functional capacity in chronic cardiopulmonary disorders because of its simplicity. The study examines the physiological responses during encouraged 6MWT in patients with chronic obstructive pulmonary disease. Pulmonary oxygen (O2) uptake (V'O2) was measured in 20 male patients (age 66+/-6 yrs, forced expiratory volume in one second 45+/-14% predicted) during 6MWT and incremental cycling, in random order. O2 tension in arterial blood, carbon dioxide tension in arterial blood and arterial lactate concentration ([La]art) were obtained in the last 10 patients. During the 6MWT, V'O2 showed a plateau after the 3rd min (1.39+/-0.28, 1.42+/-0.31, and 1.40+/-0.30 L x min(-1), 4th, 5th and 6th min, respectively), and minute ventilation (V'E) (42+/-8 L x min(-1)) was 91% maximal voluntary ventilation. No differences were shown between 6MWT (6th min) and peak cycling exercise in V'O2 (1.40+/-0.30 versus 1.41+/-0.28 L x min(-1), respectively), cardiac frequency (126+/-13 versus 130+/-12 beats x min(-1)), or arterial respiratory blood gases. The two tests were significantly different in V'E (42+/-8 versus 47+/-8 L x min(-1), 6MWT versus cycling, respectively), carbon dioxide production (1.30+/-0.31 versus 1.45+/-0.18 L x min(-1)) and [La]art (2.9+/-1.99 versus 5.9+/-1.51 M). The study demonstrates that an encouraged 6-min walking test generates a high but sustainable oxygen uptake. Since the oxygen uptake plateau reflects the integrated response of the system, it may explain the high prognostic value of the 6-min walking test.

Aged↗
PubMed2001

[Hantavirus pulmonary syndrome in Buenos Aires Province].

In Argentina the first Hantavirus Pulmonary Syndrome (HPS) cases were characterized in 1995. Since then, Argentina is the country with the highest number of notified cases in South America. The disease is distributed in Northern, Southern and Central regions of the country, being Buenos Aires the most affected province from the Central region. In this study, we present seasonal and geographical distribution of HPS cases in Buenos Aires province, the association with diverse viral lineages and the serological characteristics of hantavirus infection in the period from 1997 up to the first semester of the year 2000. An increase in the number of HPS cases was observed up to 1999 and a gradual mortality decrease in the whole period. The cases occurred between spring and autumn, with a maximum peak in summer. The serological response was studied in 58 HPS confirmed cases at different times after the onset of symptoms. The cases were distributed between 27 localities, in two different directions from the city of Buenos Aires: South-southwest and North-northeast. More than 52% of the cases occurred in La Plata and neighboring localities. The viral genomes from 39 cases were all characterised as Andes virus (AND): AND Cent Plata 16%; AND Cent 21% and AND Cent Bs.As. 60%. Andes virus lineages only cocirculated in La Plata city. These results will contribute to establish a risk map leading to the implementation of improved strategies of prevention.

Antibodies, Viral↗
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↗
PubMed1997

Implantable cardioverter defibrillators in patients with Chagas' disease: are they different from patients with coronary disease?

Chagas' disease is a parasitic affliction, endemic to certain regions of South America, which may lead to a chronic dilated nonischemic cardiomyopathy. Ten Chagasic patients were compared to 18 coronary patients undergoing transvenous ICD implantation for ventricular tachycardia (VT), ventricular fibrillation (VF), or aborted cardiac arrest. Indications for ICD implantation were either drug intolerance or refractoriness, or no inducible tachyarrhythmia at EPS. There were no statistically significant differences between the Chagas and coronary artery disease groups with respect to age (60.2 vs 62.6 yrs), NYHA Class II (50% vs 62%), ejection fraction (31.1% vs 29.7%), and incidence of cardiac arrest (20% vs 33%), respectively. The following ICD implant and long-term follow-up variables were compared between the two groups: pacing threshold (0.94 V vs 0.95 V), defibrillation threshold (19.5 J vs 19.6 J), number of VT episodes (414 vs 435), number of spontaneous VT terminations (86 vs 187), percent efficacy of antitachycardia pacing (93.9% vs 92.1%), and total number of shocks (112 vs 145). These differences were not statistically significant. We conclude that patients with Chagas' disease, compared with coronary artery disease patients, have similar clinical characteristics leading to ICD implantation. Furthermore, no differences were found with respect to ICD and long-term follow-up characteristics between the two groups.

Age Factors↗
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

Results of delivered therapy for VT or VF in patients with third-generation implantable cardioverter defibrillators.

Third-generation implantable cardioverter defibrillators (ICDs) offer tiered therapy and can provide significant advantage in the management of patients with life-threatening arrhythmias. Three different types of ICDs were implanted in 21 patients with ventricular tachycardia (VT) or ventricular fibrillation (VF). Arrhythmia presentation was VT (76%), VF (10%), or both (14%). The mean left ventricular ejection fraction for the group was 32.4 +/- 7%. No surgical mortality occurred. Prior to discharge individual EPS determined the final programmed settings of the ICDs. During a mean follow-up of 13 +/- 1.4 months (range 2-20) the overall patient survival was 85.7%. No sudden arrhythmic or cardiac death occurred. Twenty of 21 patients (95%) received therapy by their device. In 14 patients (67%) antitachycardia pacing (ATP) was programmed "on," 13 of which was self-adaptative autodecremental mode. There were 247 VT episodes, 231 of which were subjected to ATP with 97% success and 3% acceleration or failure. Low energy shocks reverted all other VT episodes. VF episodes were successfully reverted by a single shock (93%), two shocks (6%), or three shocks (1%). We conclude that ATP therapy of VT is successful in the large majority of episodes with rare failures, and that VF episodes are generally terminated by a single ICD shock.

Cardiac Pacing, Artificial↗
PubMed1993

Changing trends in therapy delivery with a third generation noncommitted implantable defibrillator: results of a large single center clinical trial.

Thirty-four patients underwent implantation of a third generation ICD, the 4210 ATP, for sudden cardiac death or ventricular tachycardia. This device incorporates significant telemetry logs as well as a detailed analysis of each arrhythmia episode detected. During the period of clinical follow-up, a mean of 12.2 months, a total of 26,569 VT or VF detections were made. The vast majority of these were either due to atrial fibrillation, nonsustained VT, or "noise" detection, and only 6% led to device therapy. ATP was successful in 86.3% of episodes, with 3.5% accelerations and 2.4% failure of ATP trains. The majority of inappropriate therapy episodes were clustered in seven patients, and all were easily diagnosed with the aid of the extensive telemetry logs and sense histories. Of five late deaths, three were from congestive heart failure, one from cerebrovascular accident, and one unknown. These data reveal that this "tiered" therapy noncommitted ICD performs to expectations; the stored data is of significant value in diagnosing the cause of ICD therapy. In addition, ATP is an effective modality for termination of VT.

Aged↗