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BACKGROUND: Current guidelines on coronary anomalies are primarily based on expert consensus and a limited number of trials. A gold standard for diagnosis and a consensus on the treatment strategy in this patient group are lacking, especially for patients with an anomalous origin of a coronary artery from the opposite sinus of Valsalva (ACAOS) with an interarterial course. AIM: To provide evidence-substantiated recommendations for diagnostic work-up, treatment and follow-up of patients with anomalous coronary arteries. METHODS: A clinical care pathway for patients with ACAOS was established by six Dutch centres. Prospectively included patients undergo work-up according to protocol using computed tomography (CT) angiography, ischaemia detection, echocardiography and coronary angiography with intracoronary measurements to assess anatomical and physiological characteristics of the ACAOS. Surgical and functional follow-up results are evaluated by CT angiography, ischaemia detection and a quality-of-life questionnaire. Patient inclusion for the first multicentre study on coronary anomalies in the Netherlands started in 2020 and will continue for at least 3 years with a minimum of 2 years of follow-up. For patients with a right or left coronary artery originating from the pulmonary artery and coronary arteriovenous fistulas a registry is maintained. RESULTS: Primary outcomes are: (cardiac) death, myocardial ischaemia attributable to the ACAOS, re-intervention after surgery and intervention after initially conservative treatment. The influence of work-up examinations on treatment choice is also evaluated. CONCLUSIONS: Structural evidence for the appropriate management of patients with coronary anomalies, especially (interarterial) ACAOS, is lacking. By means of a structured care pathway in a multicentre setting, we aim to provide an evidence-based strategy for the diagnostic evaluation and treatment of this patient group.
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INTRODUCTION: The YEARS algorithm was successfully developed to reduce the number of computed tomography pulmonary angiography (CTPA) investigations in the diagnostic management of patients with suspected pulmonary embolism (PE), although half of patients still needed to be referred for CTPA. We hypothesized that ECG derived ventricular gradient optimized for right ventricular pressure overload (VG-RVPO), an easy to use tool for detecting PE-induced pulmonary hypertension (PH), may further improve the efficiency of the YEARS algorithm. METHODS: In this post-hoc analysis of the Years study, ECGs of 479 patients with suspected PE managed according to the YEARS algorithm were available for analysis. The diagnostic performance of VG-RVPO was assessed and likelihood ratios were calculated. RESULTS: PE was diagnosed in 88 patients (18%). In patients with confirmed PE, 34% had an abnormal VG-RVPO versus 24% of those without PE (odds ratio 1.6; 95%CI 0.94-2.6). The mean VG-RVPO was -22 ± 13 and did not differ between the two patient groups (-22 versus -20; mean difference - 2, 95% CI -4.8 to 1.3). The sensitivity of VG-RVPO for PE was 24% (95%CI 34-45), the specificity 76% (95%CI 71-80) and the c-statistic 0.45 (95% CI 0.38-0.51). When combined with the YEARS algorithm, the likelihood ratios of VG-RVPO remained close to 1.0. Ruling out PE in patients with an indication for CTPA based on a normal VG-RVPO would have resulted in 58 missed cases. CONCLUSIONS: The VG-RVPO has no diagnostic value for suspected acute PE, either as stand-alone diagnostic test or combined with the YEARS algorithm. CONDENSED ABSTRACT: This post-hoc analysis of the YEARS study failed to demonstrate incremental diagnostic value of VG-RVPO for acute PE, either as stand-alone diagnostic test or combined with the YEARS algorithm. Nevertheless, the role of VG-RVPO recorded on admission could potentially be valuable in the risk stratification of PE during hospitalization, although this remains to be studied.
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Eletrocardiografia , Embolia Pulmonar , Angiografia por Tomografia Computadorizada , Ventrículos do Coração , Humanos , Artéria Pulmonar , Embolia Pulmonar/diagnósticoRESUMO
Ventricular assist device (VAD) implantation is an established treatment modality for patients with end-stage heart failure, and improves symptoms and survival. In the Netherlands, it is not yet routinely considered in patients with congenital heart disease and failing systemic right ventricle (SRV). Recently, a VAD was implanted in 2 SRV patients, one who underwent a Mustard procedure during infancy for transposition of the great arteries (male, 47 years old) and one with a congenitally corrected transposition of the great arteries (male, 54 years old). The first patient is doing well >1 year after implantation; the second patient will be discharged home soon. These examples and other reports demonstrate the feasibility of adopting VAD implantation into routine care for SRV failure. In conclusion, patients with SRV failure may be suitable candidates for VAD implantation: they are relatively young, usually have a preserved subpulmonary left ventricular function, and their specific anatomical and physiological characteristics often make them unsuitable for cardiac transplantation. Therefore it is important to recognise the possibility of VAD implantation early in the process of SRV failure, and to timely refer these patients to a heart failure clinic with experience in VAD implantation in this group of patients for optimisation, screening, and implantation.
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Coarctation of the aorta (CoA) is a congenital heart defect that is associated with a bicuspid aortic valve (BAV), ascending aorta dilatation, intracerebral aneurysms, and premature atherosclerotic disease. The first presentation during late adulthood is rare and is frequently driven by late sequelae. Hypertrophic collateral arteries can develop aneurysms which are at risk for spontaneous rupture, however, treatment recommendations for these aneurysms are scarce. Here, we describe the clinical course and percutaneous treatment strategy of a patient with a late diagnosis of a pin-point CoA, a BAV with moderate regurgitation, and an exceptionally large aneurysm of a collateral artery. A 59-year-old woman was diagnosed with Streptococcus bovis endocarditis of a BAV with moderate aortic valve regurgitation and small vegetation (<5 mm) on the non-coronary cusp. Work-up revealed hypertension and adenocarcinoma in situ of the ascending colon, considered the bacteremia porte d'entrée, for which a curative hemicolectomy was performed. Echocardiography showed a narrowing of the aorta distal from the origin of the left subclavian artery with the antegrade diastolic flow with a pathognomonic "sawtooth" pattern and an estimated pressure gradient of >70 mmHg. Computed tomography angiography (CTA) showed a network of well-developed collateral arteries and a levoatriocardinal vein. One of the collateral arteries arising from the left subclavian artery revealed an exceptionally large aneurysmatic dilation (29 × 24 × 24 mm). The invasive assessment confirmed a hemodynamically significant CoA. Treatment involved balloon dilatation and placement of a covered stent at the site of the pin-point CoA and a percutaneous coronary intervention (PCI) of the stenosis in the left anterior descending artery. No residual gradient over the CoA was observed. Antihypertensive drugs could be discontinued, and CTA performed 4 months later showed regression and thrombosis of the numerous collaterals and, importantly, thrombosis of the large aneurysm. This case illustrates the late diagnosis of CoA with associated congenital heart defects and late sequelae including hypertension, BAV endocarditis, coronary artery disease, and aneurysm formation of the extensive collateral network. The patient underwent pharmacological and percutaneous treatment, ultimately resulting in the alleviation of the CoA, normalization of the blood pressure, reduction of collateral flow, and thrombosis of the large aneurysm of the collateral artery.
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Nuclear cardiology is well established in clinical diagnostic algorithms for many years. This is an update 2008 of the first common position paper of the German Association of Nuclear Medicine and the German Association of Cardiology, Heart and Circulation Research published in 2001 aiming at an overview of state-of-the-art scintigraphic methods.
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Cardiopatias/diagnóstico por imagem , Medicina Nuclear/tendências , Análise Custo-Benefício , Humanos , Imagem de Perfusão do Miocárdio/métodos , Medicina Nuclear/economia , Radiografia , Compostos Radiofarmacêuticos , Sociedades Médicas , Radioisótopos de TálioRESUMO
BACKGROUND: Patients with systemic sclerosis (SSc) are at risk for developing pulmonary hypertension (PH) which is a major cause of death in this population. Echocardiographic (TTE) derived pulmonary arterial pressure (PAP) can be unreliable for the early detection of PH. Previous studies demonstrate that the ECG derived ventricular gradient optimized for right ventricular pressure overload (VG-RVPO) can detect PH in a heterogeneous population suspected of PH. The aim of this study is to assess the use of the VG-RVPO as a screening and monitoring instrument of early PH in SSc patients. METHODS: Serial ECGs and TTEs from twenty-seven SSc patients who underwent right heart catheterization (RHC) were retrospectively analyzed. The changes in PAP and VG-RVPO over time were studied in patients with and without diagnosed PH. RESULTS: Twenty-four patients (52.5% female, mean age 58.4â¯years SD 14.3) were studied. In eleven patients PH was confirmed with RHC. In these patients VG-RVPO was significantly higher -8⯱â¯19 than in patients without PH -23⯱â¯10â¯mV·ms, (Pâ¯<â¯0.05). In addition, in PH patients the VG-RVPO increased over time in contrast to patients without PH (Pâ¯<â¯0.01). The VG was more sensitive to detect disease progression in earlier stages of disease as compared to echocardiographic derived PAP. CONCLUSIONS: The VG-RVPO is a sensitive, non-invasive and cost effective tool for early detection of PH in SSc patients. Serial measurements indicate that the VG-RVPO can be used as a follow-up instrument and outperforms TTE to detect early changes in right ventricular pressure over time.
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Ecocardiografia/normas , Eletrocardiografia/normas , Hipertensão Pulmonar/diagnóstico por imagem , Hipertensão Pulmonar/fisiopatologia , Escleroderma Sistêmico/diagnóstico por imagem , Escleroderma Sistêmico/fisiopatologia , Adulto , Idoso , Diagnóstico Precoce , Ecocardiografia/métodos , Eletrocardiografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
BACKGROUND: Little is known on the clinical course of tricuspid regurgitation (TR) in patients with repaired tetralogy of Fallot (rTOF) and which patients are at particular risk. This study aims to determine TR course, characteristics associated with TR progression, and the prognostic relevance of TR in rTOF patients. METHODS: In this dualcenter cohort study, rTOF patients from a prospective national registry with ≥1 cardiac magnetic resonance imaging study and ≥2 echocardiograms available were included. Clinical and imaging data were collected. Cox hazards regression analysis was used to assess patient characteristics associated with progression to severe TR and whether severe TR was associated with the combined clinical endpoint of tachyarrhythmia, heart failure, and death, as time-dependent factor. RESULTS: A total of 216 patients were included (57% men, age 34±12years); 11 patients (5%) had severe TR at baseline. During 7.6±3.5years of follow-up, progression to severe TR occurred in 15 patients (7%). NYHA class ≥2 (HR 5.38, 95%-C.I. 1.91-15.16, p=0.001) and moderate baseline TR (HR 13.10, 95%-C.I. 2.95-58.21, p=0.001) were independently associated with progression to severe TR. Adverse events occurred in 47 patients (22%). The occurrence of severe TR was independently associated with adverse events (HR 3.48, 95%-C.I. 1.68-7.21, p=0.001). CONCLUSIONS: In this study, severe TR was present in 12% of adult rTOF patients during 7.6years, and progression to severe TR was most likely in symptomatic patients with moderate baseline TR. In these patients, close surveillance is warranted, because the occurrence of severe TR was associated with worse prognosis.
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Implante de Prótese de Valva Cardíaca/tendências , Tetralogia de Fallot/diagnóstico por imagem , Tetralogia de Fallot/cirurgia , Insuficiência da Valva Tricúspide/diagnóstico por imagem , Insuficiência da Valva Tricúspide/cirurgia , Adulto , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Sistema de Registros , Tetralogia de Fallot/epidemiologia , Insuficiência da Valva Tricúspide/epidemiologia , Adulto JovemRESUMO
DNA (deoxyribonucleic acid) signals that induce the G2 checkpoint response were examined using proliferative secondary cultures of diploid human fibroblasts. Treatments that generated DNA double-strand breaks (DSBs) directly were effective inducers of checkpoint response, generally producing >80% inhibition of mitosis (G2 delay) and the kinase activity of M-phase-promoting factor within 2 h of treatment. Effective inducers of G2 checkpoint response included gamma-irradiation and the cancer chemotherapeutic drugs, bleomycin and etoposide. Treatments that produced DNA single-strand breaks, directly or indirectly through nucleotide excision repair, were not effective inducers of G2 delay. Ineffective treatments included incubation with camptothecin, an inhibitor of topoisomerase I (topo I), and irradiation with sublethal fluences of UVC, followed by incubation with aphidicolin. Transient severe inhibition of DNA synthesis with aphidicolin did not affect mitosis substantially, suggesting that the replication arrest input to the G2 checkpoint required more than brief inhibition of DNA synthesis. In contrast, moderate camptothecin-induced inhibition of DNA synthesis was associated with a strong inhibition of mitosis that developed 4-12 h after drug treatment. This result suggested that G2 delay was not expressed until the cells that were in S-phase at the time of treatment with camptothecin proceeded into G2. DNA damage was not necessary for induction of mitotic delay. An inhibitor of topoisomerase II (topo II), ICRF-193, which inhibits chromatid decatenation in G2 cells without damaging DNA, induced a severe inhibition of mitosis and M-phase-promoting factor kinase activity. The results suggest that DNA double-strand breaks and insufficiency of chromatid decatenation effectively induce the G2 checkpoint response, but DNA single-strand breaks do not.
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DNA/fisiologia , Diploide , Fase G2/genética , Calibragem , Camptotecina/farmacologia , Células Cultivadas , Cromatografia/métodos , Quebra Cromossômica , Dano ao DNA/efeitos dos fármacos , Dano ao DNA/efeitos da radiação , Fibroblastos/efeitos dos fármacos , Fibroblastos/fisiologia , Fibroblastos/efeitos da radiação , Fase G2/efeitos dos fármacos , Fase G2/efeitos da radiação , Humanos , Mitose/efeitos dos fármacosRESUMO
AIM: Elevated iodine intake is a serious problem in the diagnostic and therapeutic application of (131)iodine in patients with differentiated thyroid cancer. Therefore, iodine avoidance is necessary 3 months in advance. Additionally, endogenous stimulation requires withdrawal of thyroid hormone substitution for 4 weeks. Exogenous stimulation using recombinant human TSH (rhTSH) enables the continuous substitution of levothyroxine, which contains 65.4% of its molecular weight in iodine. Thus, a substantial source of iodine intake is maintained during exogenous stimulation. Although this amount of stable iodine is comparable to the iodine intake in regions of normal iodine supply, it may reduce the accumulation of radioiodine in thyroid carcinoma tissue. The aim of this study was to assess the iodine excretion depending on different ways of stimulation. METHODS: Iodine excretion was measured in 146 patients in the long term follow up after differentiated thyroid carcinoma. Patients were separated into 2 groups, those on hormone withdrawal (G I) and rhTSH-stimulated patients on hormone substitution (G II). RESULTS: Iodine excretion was significantly lower in hypothyroid patients (G I, median 50 micro g/l, range: 25-600 micro g/l) than in those under levothyroxine medication (G II, median 75 micro g/l, 25-600 micro g/l, p <0.027). TSH in G I (median 57.0 micro U/ml, range: 14.4-183 micro U/ml) was significantly lower (p <0.001) than in G II (117 micro U/ml, 32.2-281 micro U/ml). CONCLUSION: Iodine excretion was higher in patients under rhTSH-stimulation than after hormone withdrawal. This may indicate an increased iodine pool in rhTSH-stimulated patients (deiodination of levothyroxine), thus limiting the sensitivity of radioiodine scanning to the level of endogenous stimulation despite significantly higher TSH levels during rhTSH-stimulation.
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Radioisótopos do Iodo/farmacocinética , Radioisótopos do Iodo/uso terapêutico , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Neoplasias da Glândula Tireoide/radioterapia , Tireotropina , Adenocarcinoma Folicular/diagnóstico por imagem , Adenocarcinoma Folicular/radioterapia , Carcinoma Papilar/diagnóstico por imagem , Carcinoma Papilar/radioterapia , Diagnóstico Diferencial , Feminino , Humanos , Radioisótopos do Iodo/urina , Masculino , Pessoa de Meia-Idade , Cintilografia , Proteínas Recombinantes , Tireotropina/farmacocinética , Distribuição TecidualRESUMO
Airway epithelial cells are well-known producers of thymus- and activation-regulated chemokine (TARC), a Th2 cell-attracting chemokine that may play an important role in the development of allergic airway inflammation. However, the mechanism responsible for up-regulation of TARC in allergy is still unknown. In the asthmatic airways, loss of expression of the cell-cell contact molecule E-cadherin and reduced epithelial barrier function has been observed, which may be the result of an inadequate repair response. Because E-cadherin also suppressed multiple signaling pathways, we studied whether disruption of E-cadherin-mediated cell contact may contribute to increased proallergic activity of epithelial cells, e.g., production of the chemokine TARC. We down-regulated E-cadherin in bronchial epithelial cells by small interference RNA and studied effects on electrical resistance, signaling pathways, and TARC expression (by electric cell-substrate impedance sensing, immunodetection, immunofluorescent staining, and real-time PCR). Small interference RNA silencing of E-cadherin resulted in loss of E-cadherin-mediated junctions, enhanced phosphorylation of epidermal growth factor receptor (EGFR), and the downstream targets MEK/ERK-1/2 and p38 MAPK, finally resulting in up-regulation of TARC as well as thymic stromal lymphopoietin expression. The use of specific inhibitors revealed that the effect on TARC is mediated by EGFR-dependent activation of the MAPK pathways. In contrast to TARC, expression of the Th1/Treg cell-attracting chemokine RANTES was unaffected by E-cadherin down-regulation. In summary, we show that loss of E-cadherin-mediated epithelial cell-cell contact by damaging stimuli, e.g., allergens, may result in reduced suppression of EGFR-dependent signaling pathways and subsequent induction of Th2 cell-attracting molecule TARC. Thus, disruption of intercellular epithelial contacts may specifically promote Th2 cell recruitment in allergic asthma.
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Asma/imunologia , Brônquios/imunologia , Caderinas/fisiologia , Mucosa Respiratória/imunologia , Células Th2/imunologia , Brônquios/metabolismo , Caderinas/antagonistas & inibidores , Caderinas/genética , Células Cultivadas , Quimiocina CCL17 , Quimiocinas CC/análise , Quimiocinas CC/genética , Quimiocinas CC/metabolismo , Citocinas/metabolismo , Regulação para Baixo , Receptores ErbB/metabolismo , Humanos , Quinases de Proteína Quinase Ativadas por Mitógeno/imunologia , Fosforilação , RNA Interferente Pequeno/farmacologia , Linfopoietina do Estroma do TimoRESUMO
Thymus and Activation-Regulated Chemokine (TARC) may be critical in Th2 cell recruitment in allergic inflammation; however, the mechanisms of allergen-induced TARC release are unclear. Since airway epithelium is the first line of defense to inhaled allergens, we questioned whether house dust mite allergen (Der p) can induce TARC expression in bronchial epithelial cells, how this is regulated at the molecular level, and if micro-environmental cytokines augment this effect. We examined the effects of Der p and the cytokines IL-4 and TGF-beta on TARC expression in 16HBE cells and primary bronchial asthma epithelium. Real-time PCR and immunofluorescence demonstrated that Der p induces TARC expression in bronchial epithelium. Supernatants from Der p-stimulated 16HBE cells were able to induce TARC-dependent T cell trafficking. IL-4 and TGF-beta cooperatively enhanced Der p-induced TARC expression in 16HBE cells. Specific inhibitors, immunodetection, and gel-shifts revealed that these effects are mediated by phosphorylation of the epidermal growth factor receptor (EGFR), mitogen-activated protein kinase (MAPK) signaling and subsequent nuclear factor (NF)-kappaB activation. A Disintegrin And Metalloproteinase (ADAM), a family of proteins involved in shedding of various growth factors, was shown to be responsible for EGFR activation. The increase in TARC production by direct interaction of Der p with the bronchial epithelium may be an important initial step in the generation of allergic inflammation, which is further potentiated by micro-environmental cytokines. Interference with ADAM or EGFR activity may be a novel promising target to prevent TARC release and subsequent allergic inflammation.
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Antígenos de Dermatophagoides/imunologia , Quimiocinas CC/genética , Epitélio/efeitos dos fármacos , Receptores ErbB/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Interleucina-4/farmacologia , Sistema Respiratório/efeitos dos fármacos , Fator de Crescimento Transformador beta/farmacologia , Adulto , Idoso , Animais , Antígenos de Dermatophagoides/farmacologia , Movimento Celular/efeitos dos fármacos , Células Cultivadas , Quimiocina CCL17 , Quimiocinas CC/metabolismo , Dermatophagoides pteronyssinus , Inibidores Enzimáticos/farmacologia , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Epitélio/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Humanos , Pessoa de Meia-Idade , Modelos Genéticos , NF-kappa B/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Sistema Respiratório/citologia , Transdução de Sinais/efeitos dos fármacos , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidoresRESUMO
OBJECTIVE: To evaluate the impact of long term cardiac resynchronisation therapy (CRT) on left atrial and left ventricular (LV) reverse remodelling and reversal to sinus rhythm (SR) in patients with heart failure with atrial fibrillation (AF). PATIENTS: 74 consecutive patients (age 68 (8) years; 67 men) with advanced heart failure and AF (20 persistent and 54 permanent) were implanted with a CRT device. MAIN OUTCOME MEASURES: Patients were evaluated clinically (New York Heart Association (NYHA) class, quality of life, six minute walk test) and echocardiographically (LV ejection fraction, LV diameters, and left atrial diameters) before and after six months of CRT. Additionally, restoration of SR was evaluated after six months of CRT. RESULTS: NYHA class, quality of life score, six minute walk test, and LV ejection fraction had improved significantly after six months of CRT. In addition, left atrial and LV end diastolic and end systolic diameters had decreased from 59 (9) to 55 (9) mm, from 72 (10) to 67 (10) mm, and from 61 (11) to 56 (11) mm, respectively (all p < 0.01). During implantation 18 of 20 (90%) patients with persistent AF were cardioverted to SR. At follow up 13 of 18 (72%) patients had returned to AF and none had spontaneously reverted to SR; thus, only 5 of 74 (7%) were in SR. CONCLUSION: Six months of CRT resulted in significant clinical benefit with significant left atrial and LV reverse remodelling. Despite these beneficial effects, 93% of patients had not reverted to SR.
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Fibrilação Atrial/terapia , Estimulação Cardíaca Artificial/métodos , Insuficiência Cardíaca/terapia , Idoso , Fibrilação Atrial/diagnóstico por imagem , Fibrilação Atrial/etiologia , Teste de Esforço , Feminino , Átrios do Coração/diagnóstico por imagem , Átrios do Coração/patologia , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Marca-Passo Artificial , Qualidade de Vida , Resultado do Tratamento , UltrassonografiaRESUMO
Bioimpedance monitoring may aid in treating heart failure. Mean thoracic electrical impedance (Zo) is inversely proportional to thoracic fluid volume and may offer greater sensitivity for detecting thoracic fluid. OBJECTIVE. Compare bioimpedance monitoring thoracic fluid detection to that of chest x-ray. METHOD. Prospective convenience sample. SETTING. 1000 bed teaching hospital. PARTICIPANTS. Patients with suspected heart failure and shortness of breath. A single blinded radiologist interpreted chest x-rays as: normal, cardiomegaly, or abnormal pulmonary fluid. STATISTICS. General linear model with post hoc Bon Ferroni pairwise comparisons. RESULTS. 131 patients, mean age 66.8 years, 64.3% male, with an initial mean Zo=18 ohms. There was a significant difference (p<0.0002) between patients with cardiomegaly (Zo=17.5+/-5.5) or abnormal pulmonary fluid on chest x-ray (Zo=17.2+/-4.2) compared to normals (Zo=23.4+/-5.4). There was no difference between cardiomegaly and abnormal pulmonary fluid patients. CONCLUSION. Bioimpedance measurement may detect pulmonary fluid not apparent on chest radiograph. (c)2000 by CHF, Inc.
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In clinical and research studies, images obtained using carrier-added meta-[123I]iodobenzylguanidine (c.a. [123I]MIBG) have shown quite variable quality, with varying levels of uptake in lung, liver and mediastinum; this is a significant problem for quantification of the myocardial uptake by means of region ratios. First experimental and preliminary human data in respect of no-carrier-added (n.c.a.) [123I]MIBG are indicative of improved imaging quality. The aim of the present study was to evaluate the clinical value of myocardial scintigraphy with n.c.a. [123I]MIBG in patients with tachyarrhythmias. The study population comprised 24 patients with tachyarrhythmogenic diseases routinely studied by cardiac single-photon emission tomography (SPET) with [123I]MIBG. Twelve of the 24 patients were studied with c.a. [123I]MIBG (seven females and five males; mean age 42+/-13 years, range 20-60 years), whereas the other 12 were studied with n.c.a. [123I]MIBG (ten females, two males; mean age 41+/-11 years, range 18-60 years, P=NS). For quantification of the specific uptake in the different organs, count ratios were calculated on SPET images acquired 4 h p.i. Visual analysis of all [123I]MIBG scans showed improved image quality (improved contrast between heart and neighbouring organs) in n.c.a. studies as compared with c.a. studies. A significantly higher heart/left atrial blood ratio was found in the n.c.a. studies as compared with the c.a. studies (10.3+/-3.2 vs 5.3+/-1.3, P=0.0003); furthermore, significantly higher heart/lung and heart/liver ratios (2.5+/-0.6 vs 1.5+/-0.3, P=0.0002, and 0.8+/-0.2 vs 0.6+/-0.1, P=0.0006, respectively) were obtained in the c.a. studies, whereas lung/left atrial blood and liver/left atrial blood ratios showed no significant differences (4.2+/-1.3 vs 3.6+/-1.1, P=0.39, and 13.7+/-5.2 vs 9.6+/-2.2, P=0.21, respectively). In conclusion, the use of n.c.a. [123I]MIBG yields a significantly higher myocardial uptake associated with improvement in contrast between the heart and neighbouring organs and is therefore superior to the commercially available c.a. [123I]MIBG for use in clinical and research studies of the myocardial presynaptic sympathetic nervous system. Furthermore, our data indicate that for quantification the use of a left atrial blood reference region of interest, which is only available on SPET studies, is to be recommended.