Biomedical subjects

J M Wu

Publications and source records attributed to J M Wu.

At least 37 records · Page 2Linked to original sources

PubMed2001

Attenuation of radiation dose by the skull base bone in patients with nasopharyngeal carcinoma: clinical importance.

PURPOSE: To measure the degree of attenuation of radiation dose by the skull base bone in patients with nasopharyngeal carcinoma (NPC) and to study its clinical importance. MATERIALS AND METHODS: Isodose distribution in 11 patients with NPC who received bilaterally opposed large-field irradiation (1.8 Gy per fraction) was studied with a three-dimensional treatment planning system with tissue inhomogeneity correction. Also studied were the sites of local tumor recurrence in 37 patients with NPC and skull base destruction (>/=0.5 cm) or intracranial invasion treated with radiation therapy from January 1989 to December 1992. Regression analyses were performed. RESULTS: In the dosimetric study, the low-dose areas (<1.65 Gy) were located at the level of the skull base in all 11 patients. A significantly positive correlation between the maximum width of the skull base bone and the low-dose volume (<1.65 Gy) was demonstrated (P =.003, linear regression). In the clinical study, local tumor recurrence was noted in 18 patients (49%). The sites of local recurrence included skull base in 16 patients (43%) and nasopharynx in six patients (16%). Wider skull base bone was a significant predictor of skull base recurrence after radiation therapy (P =.03, logistic regression). CONCLUSION: Herein demonstrated is the inadequacy of the radiation dose over the skull base due to attenuation by the skull base bone. The relationship between width of skull base bone and skull base tumor recurrence also is established.

Adult↗

PubMed2001

Mechanism of cardioprotection by resveratrol, a phenolic antioxidant present in red wine (Review).

Coronary heart disease (CHD) has been and remains a major contributor to morbidity and mortality in developed countries. The most common form of CHD in the western world is atherosclerosis (AS), especially of the major coronary arteries. Failure to maintain an intact endothelium, as a result of episodic and/or persistent injury and perturbation of the vascular endothelium, promotes formation of fatty streaks which are considered initiation events of AS. Cellular constituents contributing to endothelial injury include endothelial cells, monocytes, platelets, and smooth muscle cells. Individuals diagnosed with AS face complex, enduring clinical complications and enormous medical costs. Simple and easily compliant prevention and treatment measures are therefore strategic considerations in the management of this vascular disease. Based on known risk factors for CHD, priorities in AS prevention should include smoking cessation, blood pressure control, and diet modification. In recent years, the possible benefits of low to moderate consumption of alcoholic beverages, particularly of red wine, in the prevention of heart disease has received increasing attention and debate in the popular media as well as in the scientific community. Such attention has been prompted by research findings supporting a relationship between red wine consumption and the French paradox. This phenomenon refers to people residing in certain parts of France where red wine is customarily consumed during meals having a low CHD mortality, despite living a lifestyle considered to have comparably high CHD risks, as those in the US and many other developed countries. Studies have reported that the cardioprotective effects of red wine are greater than those attributed solely to ethanol and other types of alcoholic beverages. The mechanism(s) underlying the greater CHD protective benefits of red wine have not been elucidated. Recently the polyphenol resveratrol (3,5,4'-trihydroxy-trans-stilbene), known to be abundantly present in red wine, compared to white wine, beer, or spirits, has been demonstrated to elicit a broad spectrum of biological responses in in vitro and in animal studies, including effects that are compatible with the cardioprotective roles proposed for red wine. These recently described effects of resveratrol will be reviewed in this article. We will first summarize published data showing an inverse association between consumption of alcoholic beverages/red wine and risk of CHD. A review of biosynthesis of resveratrol and its presence in food groups and wines will follow. Recent studies relating exposure to wine/resveratrol with reduction in myocardial damage during ischemia-reperfusion, modulation of vascular cell functions, inhibition of LDL oxidation, and suppression of platelet aggregation will be presented. The last section of this review will focus on a discussion of mechanism(s) by which resveratrol acts as a potential cardioprotective agent.

Animals↗

PubMed2001

Cell growth and gene modulatory activities of Yunzhi (Windsor Wunxi) from mushroom Trametes versicolor in androgen-dependent and androgen-insensitive human prostate cancer cells.

The incidence of prostate cancer varies greatly throughout the world; it is highest in African-Americans and lowest in the Asian populations of China, India, and Japan. Geographical differences in both prevalence of latent prostate cancer and mortality have been postulated to be influenced by diverse tumor-promoting and protective factors, both environmental and dietary. Prostate cancer is a tumor with an extremely long latency; the pattern of prostate tumorigenesis, in terms of the display and sequence of appearance of particular molecular or biochemical features, or morphological changes, characterizing different stages of the carcinogenic process, is expected to be heterogeneous. Some insights into tumor heterogeneity and progression can be obtained from studies using cell lines, particularly those derived from different anatomical sites. The present study aims to investigate whether hormone-responsive LNCaP and androgen-refractory JCA-1, PC-3, and DU-145 prostate cancer cells are responsive to Yunzhi (YZ), a proprietary dietary supplement prepared from extracts of Trametes versicolor, also known as Coriolus versicolor (a mushroom consumed by Chinese for its purported health benefits), and to elucidate its mechanism of action. Ethanolic extracts (70%) of YZ significantly reduced LNCaP cell growth, down-regulated the levels of secreted PSA, but had less effects on the expression of intracellular PSA and did not affect levels of the androgen receptor. In androgen-unresponsive prostate cancer cells, YZ had a much less pronounced suppressive effect on proliferation of PC-3 and DU-145 cells, compared to LNCaP, and was inactive against JCA-1 cells. Western blot analyses show that the expression of Rb, a key regulatory protein in G1/S transition, and PCNA, integrally involved in mammalian cell DNA replication, were significantly reduced by treatment with YZ in PC-3 and DU-145 cells, respectively. In contradiction, none of these biochemical parameters were affected in JCA-1 cells under identical treatment conditions. Further analysis shows that YZ increased the levels of signal transducer and activator family of transcription factors STAT 1 and STAT 3 in JCA-1 and not LNCaP cells. The greater sensitivity of LNCaP cells to this polysaccharopeptide raises the possibility that YZ may be considered as an adjuvant therapy in the treatment of hormone responsive prostate cancer; additionally, it may have chemopreventive potential to restrict prostate tumorigenic progression from the hormone-dependent to the hormone-refractory state.

Androgens↗

PubMed2001

[Study on the preparation of baicalin complex with phospholipid].

OBJECTIVE: To choose the optimization conditions for the formation of baicalin complex with phospholipid. METHOD: A reasonable criterion of accurate evaluation was established, by which such factors as temperature, the ratio of baicalin to phospholipid and the concentration of reactants were examined and the orthographic design was used. RESULT: The best conditions were obtained through statistical analysis and proof test. CONCLUSION: The formation of baicalin complex with phospholipid was greatly influenced by the solvent, concentration and reactant ratio.

Drug Carriers↗

PubMed2001

[Preparation and evaluation of in-situ synthesis zeolite gas-liquid modified columns].

A new kind of NaA zeolite column has been prepared by in-situ synthesis technique. In comparing with traditional coating method, the in-situ NaA zeolite carrier is much more uniform and rigid. Several kinds of zeolite gas-liquid modified columns have been prepared with this in-situ technology, which showed satisfactory features in separation property and thermal stability. The successful utilization of mini-length and wide-bore columns showed good practical prospect of this new kind of zeolite column.

Chromatography, Gas↗

PubMed2000

Effect of resveratrol on intimal hyperplasia after endothelial denudation in an experimental rabbit model.

The ability of resveratrol to inhibit vascular intimal thickening was tested in an experimental model in which endothelial denudation was performed in the normal rabbit iliac artery. Resveratrol (2 approximately 4mg/ kg/d) was administered intragastrically for 5 weeks beginning 1 week before denudation. At the higher concentration of resveratrol, the intimal hyperplasia of injured vascular wall was effectively inhibited; the intimal proliferation index also was significantly less than that in the untreated control group (0.28 +/- 0.07 vs 0.41 +/- 0.13, respectively, p<0.01); the relative luminal area increased from 0.38 +/- 0.06 in the untreated control group to 0.53 +/- 0.10 in the resveratrol treatment group (p < 0.001); and the count of smooth muscle cells in the thickened intima was statistically significantly reduced in the high dose resveratrol treatment group than that in the untreated group (1,115 +/- 510 vs 1,796 +/- 963, respectively, p < 0.05). Resveratrol added to the culture media of cultured rabbit vascular smooth muscle cells inhibited DNA synthesis in a dose-dependent manner. These results showing that resveratrol is capable of inhibiting intimal hyperplasia of injured artery raise the possibility that this polyphenol might have clinical potential in prevention and treatment of restenosis after angioplasty.

Animals↗

PubMed2000

Apoptosis and restriction of G(1)/S cell cycle by fenretinide in Burkitt's lymphoma mutu I cell line accessed with bcl-6 down-regulation.

Fenretinide (4-HPR) is a synthetic retinoid with cancer chemopreventative potential and clinically manageable side effects, compared to the prototype retinoid, all-trans retinoic acid (RA). 4-HPR has been shown to modulate cell proliferation and induce apoptosis in a variety of human tumor cell types, but its effects on B-cell non-Hodgkin's lymphomas (NHL-B) have not been explored. Treatment of Burkitt's lymphoma Mutu I cells with 3 microM 4-HPR is accompanied by growth arrest, induction of apoptosis, and restricted progression of the cell cycle at the G(1)/S checkpoint. We also observed that 4-HPR elicited a reduced expression of bcl-6 in these cells, which supports the proposed role of bcl-6 as an anti-apoptotic gene. While 4-HPR treatment had no effect on total Rb gene expression, it significantly reduced the state of hyperphosphorylation of Rb, resulting in the predominant existence of Rb in the underphosphorylated state.

Apoptosis↗

PubMed2000

Fenretinide-induced caspase 3 activity involves increased protein stability in a mechanism distinct from reactive oxygen species elevation.

Fenretinide (4-HPR) is a synthetic retinoid that displays a broad range of biological effects and has also demonstrated clinical efficacy as a chemopreventative agent. One cellular activity of 4-HPR is its ability to induce apoptosis. This effect has been proposed to relate to changes in intracellular reactive oxygen species. We show herein that a 1-h treatment of HL-60 cells with 4-HPR led to a dose-dependent increase in hydroperoxides. Pretreatment of cells with the antioxidant vitamin C abolished apoptosis, measured as the appearance of the sub-G1 peak, in 4-HPR-treated cells. The retinoid also elicited a 3.6-fold increase in caspase 3 activity; however, this increase was not affected by vitamin C treatment. Analysis of caspase 3 protein expression by Western blot analysis revealed that 4-HPR resulted in a significant increase in the appearance of the active p17 subunit without effecting a concomitant change in p32 procaspase 3 levels. Studies on de novo synthesis and stability of caspase 3 by pulse-chase and immunoprecipitation methods show that 4-HPR-treated samples had decreased incorporation of radioactive amino acid precursors into newly synthesized procaspase 3 but, during the chase (for up to 9 h), had more labeled caspase 3 remaining when compared with controls. These studies suggest that 4-HPR may effect changes in caspase 3 activity by modulating changes in zymogen stability by a mechanism distinct from the retinoid-elicited increase in reactive oxygen species.

Acetylcysteine↗

PubMed2000

Targeting antigen-specific T cells by genetically engineered antigen presenting cells. A strategy for specific immunotherapy of autoimmune disease.

We describe a strategy for specific immunotherapy of autoimmune disease based on targeting the antigen-specific T cells in an experimental model of myasthenia gravis. To address the problem of heterogeneity of the T cell repertoire, we have genetically engineered antigen presenting cells (APCs) to process and present epitopes of the autoantigen, acetylcholine receptor (AChR), to the entire spectrum of AChR-specific syngeneic T cells. APCs derived from BALB/c mice were stably transfected with cDNA for the key immunogenic domain of the AChR alpha-subunit, flanked by sequences of the lysosome-associated membrane protein (LAMP) that direct APCs to process and present the antigen via the MHC Class II pathway. Transfected APCs strongly stimulated AChR-specific T cells from BALB/c mice. Fas ligand, or antibody to Fas, abrogated the T cell response, by inducing apoptosis of the APC-stimulated T cells. The new results of this investigation are (1) that autoreactive T cells can be effectively targeted by autologous APCs that are engineered to present the relevant autoantigen, and (2) that these specifically targeted and activated T cells can be profoundly inhibited by agents that trigger the Fas-mediated apoptosis pathway. The present findings suggest that engineering APCs for simultaneous presentation of the autoantigen and delivery of FasL will provide a powerful strategy for the elimination of autoreactive T cells.

Animals↗

PubMed2000

Synthesis and antimalarial activity of artemisinin derivatives containing an amino group.

In search of water-soluble artemisinin derivatives that are more stable than sodium artesunate, over 30 derivatives containing an amino group (compounds 3-5) were synthesized and tested in mice. All products tested (except 5a and 5b) are the beta isomers. These basic compounds combined with organic acids (oxalic acid, maleic acid, etc. ) to yield the corresponding salts. Generally, the maleates have better solubility in water than the corresponding oxalates. The aqueous solutions of these salts can be kept at room temperature for several weeks without any discernible decomposition. Compounds 3f, 3h, and 3r are much more active against P. berghei than artesunic acid by oral administration and therefore were further tested in monkeys. However, their oral efficacies are poorer than that of artesunic acid against P. knowlesi in rhesus monkeys. It is interesting to note that 3f, 3h, and 3r showed much lower efficacies against P. berghei when they were administered subcutaneously than orally.

Administration, Oral↗

PubMed2000

Dual-probe fluorescence in situ hybridization assay for detecting deletions associated with VCFS/DiGeorge syndrome I and DiGeorge syndrome II loci.

Over 90% of patients with DiGeorge syndrome (DGS) or velocardiofacial syndrome (VCFS) have a microdeletion at 22q11.2. Given that these deletions are difficult to visualize at the light microscopic level, fluorescence in situ hybridization (FISH) has been instrumental in the diagnosis of this disorder. Deletions on the short arm of chromosome 10 are also associated with a DGS-like phenotype. Since deletions at 22q11.2 and at 10p13p14 result in similar findings, we have developed a dual-probe FISH assay for screening samples referred for DGS or VCFS in the clinical laboratory. This assay includes two test probes for the loci, DGSI at 22q11.2 and DGSII at 10p13p14, and centromeric probes for chromosomes 10 and 22. Of 412 patients tested, 54 were found to be deleted for the DGSI locus on chromosome 22 (13%), and a single patient was found deleted for the DGSII locus on chromosome 10 (0. 24%). The patient with the 10p deletion had facial features consistent with VCFS, plus sensorineural hearing loss, and renal anomalies. Cytogenetic analysis showed a large deletion of 10p [46, XX,del(10)(p12.2p14)] and FISH using a 10p telomere region-specific probe confirmed the interstitial nature of the deletion. Analysis for the DGSI and the DGSII loci suggests that the deletion of the DGSII locus on chromosome 10 may be 50 times less frequent than the deletion of DGSI on chromosome 22. The incidence of deletions at 22q11.2 has been estimated to be 1 in 4000 newborns; therefore, the deletion at 10p13p14 may be estimated to occur in 1 in 200,000 live births.

Chromosome Deletion↗

PubMed2000

Resveratrol decreases early signaling events in washed platelets but has little effect on platelet in whole blood.

Resveratrol, a polyphenolic compound found in red wines, is believed to be a contributor in decreasing the incidence of coronary heart disease. Although its primary target is unknown, it blocks aggregation of washed platelets by an ill-defined mechanism. We show that resveratrol, at 10-50 microM, blocked aggregation induced by collagen (5 microg/ml), thrombin (0.2 units/ml), and ADP (10 microM). This affect was not overcome by adding exogenous human fibrinogen to the assay, suggesting that an early (wave I) signaling step in the alpha(IIb)beta(3) activation cascade was impaired. To explore this possibility we examined the effect of resveratrol on activation of MAP kinases. In the platelet, MAP kinases become activated as a consequence of agonist binding and not of aggregation, which itself induces signaling events. In fact, we find that collagen-induced activation of MAP kinases is superinduced in the presence of RGDS, an aggregation-blocking peptide. Resveratrol, at concentrations of 10 microM and greater, inhibited MAP kinase activation induced by collagen (in the absence and presence of RGDS peptide), thrombin, and ADP. These data indicate that resveratrol blocks receptor-mediated signaling events in washed platelets. In comparison, resveratrol has poor antiplatelet activity in whole blood. Under these conditions aggregation was not affected by 50-100 microM resveratrol. Concentrations of 200 microM resveratrol were needed to cause a 30-60% decrease in platelet aggregation in whole blood. Together these studies suggest that resveratrol is a potent inhibitor of platelet signaling responses, but its antiplatelet activity is weakened or masked in circulation. Thus, although resveratrol may function as a protective agent of coronary heart disease, its affects are not solely attributed to its effects on platelets in circulation.

Adult↗

PubMed2000

Multivariate analysis of pulmonary fibrosis after electron beam irradiation for postmastectomy chest wall and regional lymphatics: evidence for non-dosimetric factors.

BACKGROUND AND PURPOSE: To evaluate the factors associated with pulmonary fibrosis after postmastectomy electron beam irradiation of chest wall and regional lymphatics in patients with breast cancer. MATERIALS AND METHODS: From July 1987 through July 1994, 109 women with stage II and III breast cancer receiving modified radical mastectomies were managed by postoperative electron beam irradiation. Doses of 46 to 50.4 Gy were delivered to the chest wall covered with bolus, internal mammary nodes, supraclavicular nodes and axillary lymph nodes via 12 or 15 MeV single portal electron beam. Seventeen patients received additional 10-16 Gy surgical scar boost via 9 MeV electron beam. Comparison of pre-treatment and post-treatment chest X-ray films were used to monitor the development of pulmonary fibrosis. RESULTS: Only Grade 1 radiation-induced late pulmonary toxicity was noted in 33 patients (29%). Twenty-six patients (24%) developed pulmonary fibrosis under unbolused chest wall. Lung fibrosis under bolused chest wall was noted in 11 patients (10%). Statistical difference (P<0.01) was noted between the incidence of fibrosis in these two sites. In multivariate analysis of lung fibrosis under unbolus-covered chest wall, the independent prognostic factors are low body mass index (BMI) (P<0.01), tamoxifen taking (P=0.03), and no treatment interruption (P=0.03). No independent factor was associated with lung fibrosis under bolus-covered chest wall in multivariate analysis. CONCLUSIONS: In the analysis of pulmonary fibrosis induced by unbolused electron beam, BMI rather than body weight and body height is a strong prognostic factor. Tamoxifen and short overall time can predispose the development of lung fibrosis.

Adult↗

PubMed2000

Specific processing of poly(ADP-ribose) polymerase, accompanied by activation of caspase-3 and elevation/reduction of ceramide/hydrogen peroxide levels, during induction of apoptosis in host HL-60 cells infected by the human granulocytic ehrlichiosis (HGE) agent.

We studied the mechanism by which the human granulocytic ehrlichiosis (HGE) agent induces programmed cell death (apoptosis) in human promyelocytic HL-60 leukemia cells. Using several New York HGE isolates, we show that the HGE agent-elicited apoptosis is accompanied by increased processing of nuclear enzyme poly(ADP-ribose) polymerase (PARP), concurrent with a noticeable increase in caspase 3 activities. A marked increase in the amounts of the signaling molecule ceramide but not of diacylglycerol was also observed in HGE agent-infected HL-60 cells, compared with the amounts in uninfected controls. Simultaneous or prior treatment of infected HL-60 cells with the ceramide synthase inhibitor fumonisin B1 did not affect the magnitude of infection by the intracellular pathogen, as determined by both the presence of morulae and the expression of its outer surface membrane protein, p44. These results suggest that the observed changes in ceramide are generated through the sphingomyelinase pathway and not by way of de novo synthesis of ceramide. We also assayed for changes in intracellular hydrogen peroxide and show that the HGE agent causes a decrease in its concentrations in infected cells.

Apoptosis↗

PubMed2000

Initial low temperature setting in radiofrequency catheter ablation of Wolff-Parkinson-White syndrome.

Previous studies have shown that with low temperature testing for RF ablation of arrhythmias, unnecessary irreversible myocardial lesions may be avoided. In children admitted for RF ablation from June 1996 to May 1999, we evaluated the method of an initial temperature setting of 50 degrees C for a maximum of 10 seconds. If accessory pathway block occurred, the temperature setting was immediately increased to 70 degrees C and continued for 45-120 seconds (group 1). If accessory pathway block did not occur after several attempts, subsequent attempts were made with initial settings at 70 degrees C-80 degrees C at the same or different sites (group 2). Eighty patients with Wolff-Parkinson-White syndrome (mean age 11 +/- 4 years) were treated using this method. Twelve patients were excluded for various reasons. Of the remaining 68 patients, 52 (76%) had successful block of the pathway at 50 degrees C; 16 patients demonstrated block only at the higher temperature setting of 70 degrees C-80 degrees C. There were no statistically significant differences between these two groups in terms of age, weight, and location of accessory pathways. Unsuccessful 50 degrees C test ablation attempts were 1.6 +/- 2.4 in group 1 and 3.1 +/- 2.9 in group 2 (P = 0.04). Total unsuccessful attempts were 1.6 +/- 2.4 in group 1 and 8.1 +/- 7.1 in group 2 (P = 0.001). The time from application of RF energy to the time of AP block in group 1 was not significantly different from group 2. In the majority of children, successful RF ablation can be achieved by using a temperature setting of 50 degrees C, then 70 degrees C. This will prevent unnecessary permanent injury at unsuccessful attempt sites.

Adolescent↗

PubMed2000

Dangerous impact--commotio cordis.

Sudden death following blunt chest trauma is a frightening occurrence known as 'commotio cordis' or 'concussion of the heart'. It is speculated that commotio cordis could be caused by ventricular fibrillation secondary to an impact-induced energy that was transmitted via the chest wall to the myocardium during its vulnerable repolarization period. We describe a survivor of commotio cordis caused by a baseball. In this patient, an initial ventricular fibrillation was documented and converted by direct current defibrillation. Serial electrocardiographic changes (bifascicular conduction block and T wave inversion in precordial leads) were noticed in this patient. Our case suggested that coronary vasospasm might also play a role in commotio cordis.

Baseball↗

PubMed2000

Chinese herbal mixture PC SPES in treatment of prostate cancer (review).

The Chinese herbal preparation denoted PC SPES, a mixture consisting of extracts from eight herbs, is being used with increasing frequency by prostate cancer patients worldwide. Evidence has emerged that PC SPES is an effective modality that alleviates some symptoms in advanced prostate cancer in a significant proportion of patients including the cases that failed conventional therapy. This evidence as well as published data that show the effects of PC SPES in suppressing growth of prostate cancer in animal model studies, is reviewed together with the available data on the possible side effects of PC SPES. The review also covers in vitro studies that reveal the cell cycle specificity, induction of apoptosis, effects on androgen receptor and other molecular and metabolic changes induced by PC SPES that may explain its anticancer activity. Individual chemical components that are present in herbs of which PC SPES is composed, known to have anti-proliferative, antitumor, antimutagenic, analgesic and/or differentiation inducing activity, are listed and discussed. The effectiveness of PC SPES in prostate cancer is explained as due to its complex composition which may target many signal transduction and metabolic pathways simultaneously thereby eliminating the back-up or redundant mechanisms that otherwise promote cell survival when single-target agents are used.

Animals↗

PubMed2000

Ectopic atrial tachycardia in children.

BACKGROUND AND PURPOSE: Ectopic atrial tachycardia (EAT) is an unusual and potentially risky arrhythmia that can result in left ventricular dysfunction if not properly managed. In adults, EAT is mainly caused by diseased atrial myocardium and responds poorly to antiarrhythmic drugs. The characteristics of EAT in children might be different from those in adults because of their immature myocardium and the different electrophysiologic characteristics of their conduction tissue. We examined the natural history and treatment of EAT in children. METHODS AND RESULTS: From June 1990 through June 1999, 24 children (8 girls and 16 boys; median age 4 mo [1 d-10 yr]) were admitted to our hospital with a diagnosis of EAT. Fifteen had healthy hearts, six had congenital heart disease, one had myocarditis, one had bronchopulmonary dysplasia with severe pulmonary hypertension, and one had hypertrophic cardiomyopathy. Thirteen patients presented with congestive heart failure. Only four patients had symptoms of prodromal airway infection. The maximum atrial rate was 244 +/- 66 beats per minute. Atrioventricular block was documented at least once during tachycardia in 10 patients. Warm-up or cool-down phenomenon was seen at the initiation or termination of tachycardia in thirteen patients. Primary pharmacologic treatment was attempted in all patients. EAT was initially controlled in all patients using digoxin plus propranolol (18 patients), propranolol only (4), or digoxin plus procainamide (2). EAT was controlled using medication in 22 patients. Fifteen patients had sinus rhythm but did not receive medication for 39 +/- 25 months. Two patients died of uncontrolled arrhythmia, and two of underlying disease. Recurrence was seen within 3 months after initial therapy in five patients. Surgery was performed to correct the underlying heart disease in three patients with frequently recurring EAT, all of whom remained tachycardia-free after surgery, without pharmacologic treatment. The spontaneous remission rate was 75% (18/24). CONCLUSION: EAT in children without underlying heart disease can be effectively treated using antiarrhythmic drugs. Spontaneous resolution of EAT after medication in children was frequent (75%) in this series. The results of this study suggest that a step-wise approach using digoxin, a beta-blocker, and a class I antiarrhythmic drug may be the most effective treatment for EAT.

Anti-Arrhythmia Agents↗