Selection of patients for myocardial perfusion scintigraphy based on fuzzy sets theory applied to clinical-epidemiological data and treadmill test results.

Coronary artery disease (CAD) is a worldwide leading cause of death. The standard method for evaluating critical partial occlusions is coronary arteriography, a catheterization technique which is invasive, time consuming, and costly. There are noninvasive approaches for the early detection of CAD. The basis for the noninvasive diagnosis of CAD has been laid in a sequential analysis of the risk factors, and the results of the treadmill test and myocardial perfusion scintigraphy (MPS). Many investigators have demonstrated that the diagnostic applications of MPS are appropriate for patients who have an intermediate likelihood of disease. Although this information is useful, it is only partially utilized in clinical practice due to the difficulty to properly classify the patients. Since the seminal work of Lotfi Zadeh, fuzzy logic has been applied in numerous areas. In the present study, we proposed and tested a model to select patients for MPS based on fuzzy sets theory. A group of 1053 patients was used to develop the model and another group of 1045 patients was used to test it. Receiver operating characteristic curves were used to compare the performance of the fuzzy model against expert physician opinions, and showed that the performance of the fuzzy model was equal or superior to that of the physicians. Therefore, we conclude that the fuzzy model could be a useful tool to assist the general practitioner in the selection of patients for MPS.

Selection of patients for myocardial perfusion scintigraphy based on fuzzy sets theory applied to clinical-epidemiological data and treadmill test results

Coronary artery disease (CAD) is a worldwide leading cause of death. The standard method for evaluating critical partial occlusions is coronary arteriography, a catheterization technique which is invasive, time consuming, and costly. There are noninvasive approaches for the early detection of CAD. The basis for the noninvasive diagnosis of CAD has been laid in a sequential analysis of the risk factors, and the results of the treadmill test and myocardial perfusion scintigraphy (MPS). Many investigators have demonstrated that the diagnostic applications of MPS are appropriate for patients who have an intermediate likelihood of disease. Although this information is useful, it is only partially utilized in clinical practice due to the difficulty to properly classify the patients. Since the seminal work of Lotfi Zadeh, fuzzy logic has been applied in numerous areas. In the present study, we proposed and tested a model to select patients for MPS based on fuzzy sets theory. A group of 1053 patients was used to develop the model and another group of 1045 patients was used to test it. Receiver operating characteristic curves were used to compare the performance of the fuzzy model against expert physician opinions, and showed that the performance of the fuzzy model was equal or superior to that of the physicians. Therefore, we conclude that the fuzzy model could be a useful tool to assist the general practitioner in the selection of patients for MPS.

[The contribution of event monitor recorder to the diagnosis of symptoms]. / Contribuição do monitor de eventos no diagnóstico de sintomas.

PURPOSE: To evaluate the contribution of the loop memory recorder in improving the diagnosis of symptoms related to cardiac arrhythmias. METHODS: The study population was 64 patients whose Holter monitorization was inconclusive as to the diagnosis of symptoms related to cardiac arrhythmias. Each wore a patient-activated ambulatory electrocardiogram device for 15 days. The ECG recording during the occurrence of symptoms were sent to the ECG receiving center by phone. RESULTS: Two patients did not conclude the study. The majority of the patients (85.5%) experienced symptoms in the fifteen days of monitorization, and in 62.2% of these patients electrocardiographic events were observed. The main symptoms experienced by these patients were: palpitation (67.7%), dizziness (32.3%), and syncope (29%). Other symptoms like breast pain, fatigue, indisposition and dyspnea were also noted in 30.6% of the patients. The main electrocardiographic disturbances observed were: sinus tachycardia (45.5%), isolated premature beats (30.3%), supraventricular tachycardia (21.2%), ventricular tachycardia (3%) and third degree AV block (3%). We also observed that the first symptomatic recording occurred mainly in the initial days of monitorization (69.4%) in the first 5 days). The percentage of diagnoses was 35.5% in patients whose Holter monitoring had been inconclusive. CONCLUSION: The cardiac loop ECG recorder therefore achieved an important incremental diagnostic yield.

Avaliacao do cateter de subclavia como acesso vascular para hemodialise. / Evaluation of the subclavian catheter as a vascular access for hemodialysis

Os autores relatam a experiencia de 7 meses com o uso do cateter de subclavia como acesso vascular para hemodialise. Foram realizadas 81 sessoes em 11 pacientes, utilizando-se 15 cateteres colocados segundo tecnica de Seldinger pela via subclavicular. O tempo de permanencia variou de 3 a 44 dias (media 15,4). A recirculacao media, calculada em 3 pacientes, foi 11,2% e nao houve divergencia entre as diferencas pre e pos-dialise de ureia, creatinina e acido urico, quando comparados aos valores obtidos em 3 pacientes em dialise com dupla puncao de fistula de Cimino. Nao foram observadas complicacoes na puncao, sendo a dobra do cateter responsavel pelo baixo fluxo e coagulacao em 2 casos. Registrou-se apenas 1 episodio de infeccao com hemocultura e cultura da ponta do cateter positivas