Spatial Features in Body-Surface Potential Maps Can Identify Patients With a History of Sustained Ventricular Tachycardia

Abstract

Multiple body-surface ECGs contain valuable spatial features that can identify the presence of an arrhythmogenic substrate in the myocardium of patients at risk for ventricular arrhythmias. Our results compare very favorably with those achieved by any other known test, invasive or noninvasive, for arrhythmogenicity.

Identification of patients at risk for ventricular tachycardia by means of body surface potential maps

“…The QRST-integral used in [2] was applied to our study population as explained in Section 2.5. Exactness achieved in the test set as a function of the number of variables can be seen in Fig.1, where the existence of a threshold is also observed in this case.…”

“…QRST complexes were identified and processed to yield a single averaged complex for each lead. The onset and end of ECG waves were determined from the averaged complexes [2].…”

“…For comparison purposes, the method in [2] was also implemented. Feature extraction was accomplished in two steps: first, QRST-integral was calculated for each lead as the algebraic sum of the sampled potentials within QRST complex multiplied by the sampling interval of 2 ms; then, KLT was applied to QRST-integral maps.…”

“…Previous works showed that subjects at risk for VT have unique map characteristics [1], e.g. the spatial distribution of QRST integrals over the torso was used in [2] to stratify patients at risk for VT.…”

“…First, feature extraction was performed by means of linear expansions; then, a linear discriminant analysis was applied to the reduced feature space to stratify patients at risk for VT. Two approaches of linear expansions were studied: the Karhunen-Loève transform (KLT) and spatio-temporal (TS) expansions, proposed in [4] as a low-complexity approximation to KLT. For comparison purposes, the method in [2], based on the QRST integral, was also implemented.…”