RESUMEN
The multipole approach to the inverse electrocardiological problem consists of estimating the multipole components of the cardiac electric generator, starting from the measured body surface potential. This paper presents a critical investigation of the basic premise for the applicability of the multipole approach, namely the convergence of the multipole equivalent generator for the heart on the surface of an inhomogeneous body conductor. As an extension to multipole theory, a criterion for the convergence is derived. Based on realistic models for the body conductor and the cardiac electric generator, we observe that the criterion is not strictly satisfied in realistic conditions. Numerical simulations with the same models point out that the multipole equivalent generator is indeed not convergent in the strict mathematical sense. On the other hand, we show that the multipole equivalent generator yields a rather close approximation of the electrocardiological potential for intermediate values of the order of the multipole generator. A discussion is given on how to explain the apparently ambiguous results for the estimation of cardiac multipole components.
Asunto(s)
Simulación por Computador , Electrocardiografía/métodos , Corazón/fisiología , Modelos Cardiovasculares , Conductividad Eléctrica , HumanosRESUMEN
UNLABELLED: The efficacy and toxicity of a regimen adding ifosfamide to the more classical cisplatin-vindesine combination was studied in patients with advanced non-small cell lung cancer. Sixty-four good performance patients with inoperable stage III or stage IV were treated with VIP: vindesine 3 mg/m2 days 1 and 8, ifosfamide 1200 mg/m2 and platinum 30 mg/m2 days 1, 2 and 3, repeated every 4 weeks, up to a maximum of six cycles. Response rate, clinical data and radiological tests were rigourously reviewed by a panel. Overall response rate was 39% (95% confidence interval, 27%-51%) with three patients achieving a complete response; response rate in stage III was 48%. Median survival was 9 months. Toxicity consisted mainly of bone marrow toxicity and nausea/vomiting, but was manageable. There was no renal toxicity greater than grade 2, four severe infections, but no treatment-related deaths. CONCLUSION: VIP as mentioned above is very active in good performance patients with advanced non-small cell lung cancer. Its activity, together with its manageable toxicity--without severe renal or pulmonary toxicity--makes it an attractive candidate for induction chemotherapy.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Adenocarcinoma/tratamiento farmacológico , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Carcinoma de Células Grandes/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Células Escamosas/tratamiento farmacológico , Distribución de Chi-Cuadrado , Cisplatino/administración & dosificación , Cisplatino/efectos adversos , Cisplatino/uso terapéutico , Intervalos de Confianza , Femenino , Humanos , Ifosfamida/administración & dosificación , Ifosfamida/efectos adversos , Ifosfamida/uso terapéutico , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , Estudios Prospectivos , Tasa de Supervivencia , Factores de Tiempo , Vindesina/administración & dosificación , Vindesina/efectos adversos , Vindesina/uso terapéutico , Pérdida de PesoRESUMEN
A case of fibrous mesothelioma is presented. Chest films suggested an elevation of the left diaphragm and a limited pleural effusion, which was confirmed on computed tomography. Percutaneous needle biopsy showed mesothelial cells. At thoracotomy the tumor was attached to the pleura of the mediastinum by a pedicle. Complete surgical resection was possible. Clinical, radiological and histological data in literature are summarized. The radiological features of the presented case correspond to those described in the literature.