1,721,034 research outputs found
Evidence-based medicine : che cosa hanno detto i grandi trial negli ultimi anni
No full textPresentazione e discussione dei più importanti dati emersi dai grandi trials internazionali, che hanno determinato l'attuale trattamento della fibrillazione atrial
Clinical use of body surface potential mapping in cardiac arrhythmias
No full textThe electrocardiology and specifically body surface potential maps (BSPM) have two main objectives in the arrhythmologic field: 1) identification of signs of susceptibility to arrhythmias, and 2) identification of site of origin of the arrhythmias. In order to detect the susceptibility to ventricular arrhythmias, maps were recorded with different lead systems by different authors and, in particular, various methods of analysis of BSPM have been used to study repolarization potentials: QRST integral maps, eigenvector analysis, principal component analysis, autocorrelation analysis. From these analyses several markers of vulnerability to arrhythmias were identified, which demonstrated a predictive accuracy of various degree in selected patient populations. As concerns the identification of site of origin of the arrhythmias, the use of 62 leads BSPMs during endocardial pace mapping technique enabled more precise identification of the site of origin of postinfarction ventricular tachycardia episodes, compared with the use of the 12-lead electrocardiography (ECG). Recently a new electrocardiographic modality (ECG-imaging) enabled to compute non-invasively and with high resolution epicardial potential distribution and epicardial activation sequences from potentials recorded on the body surface together with cardiac computed tomography images. The ECG-imaging has been successfully applied in humans using geometrical information from computed tomography of each subject, in different heart conditions: normal heart, heart with a conduction disorder, focal activation initiated by right or left ventricular pacing, focal ventricular tachycardia and atrial flutter
Susceptibility for ventricular tachicardia and the correlation between depolarization and orthogonal components of repolarization
No full textObjective: There is a continuing need of methods to identify subgroups of patients at high risk of ventricular arrhythmias, in particular after myocardial infarction (MI). Methods: We performed a singular value decomposition of repolarization potentials in individual recordings in 134 healthy males, in 203 males with old MI and without documented sustained ventricular tachycardia (VT) and in 104 MI males with documented VT. We considered the absolute correlation coefficient between the first orthogonal component, constructed by matrix multiplication of the first left and right singular vectors and the QRS integral (RT1) and a similar index for the second component (RT2). Results: Abnormally high (more than two standard deviations above the mean) value of the RT1 had a 89% specificity for VT in MI patients. Abnormally low RT2 had specificity of 87%. Both indices combined had a 97% specificity. However, sensitivity of the combined indices was only 13%. Conclusion: Abnormalities in the correlation of orthogonal components of repolarization with depolarization are highly specific for a small group of patients with old myocardial infarction at high risk of ventricular tachycardia
Rilievo automatico delle elettromappe toraciche ed epicardiche nell'infarto acuto sperimentale. Effetti di un nuovo farmaco beta-moderatore sull'estensione dell'area ischemica.
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