Clinical use of body surface potential mapping in cardiac arrhythmias.

The 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.