Session S92.6

Non-Linear 12-Lead ECG Synthesis from Two Intracardiac Recordings

A Kachenoura, F Porée*, G Carrault, AI Hernandez

Université de Rennes
Rennes, France

Patients with Implantable Cardiac Devices (ICDs) require regularly scheduled hospital visits to perform patient follow-up and to monitor whether the ICDs are working optimally. Current developments have the objective of proposing a remote follow-up of these patients. The cardiac electrical activity acquired from the ICDs, named ElectroGraMs (EGMs), show different morphologies, when compared to those of the Surface ECG (SECG). Since the physician considers the SECG as a reference signal for the analysis of the cardiac activity, we investigate in this study the feasibility of synthesizing the standard 12-Lead ECG from only two EGMs recordings, using a non-linear filtering approach. The use of two EGMs is justified by the fact that in some practical situations the ICDs provide only two implantable electrodes. Two methods, based on a dynamic Time Delay artificial Neural Network (TDNN), are proposed: a direct method which aims to estimate 12 Transfer Functions (TF) between the two EGM and each SECG lead, and an indirect method which is based on: i) the extraction of a 3-dimensional representation of the SECG (or VectorCardioGram, VCG), ii) the orthogonalization of the two EGM signals, to derive a VectorGraM, (or VGM) by using the Principal Component Analysis (PCA) and iii) the estimation of 3 TF between the two VGM and each row of the obtained VCG. A dataset issued from 15 patients (P1 to P15) is used for evaluating the performances. P1 to P11 present ECG with a sinus rhythm, premature ventricular beats are detected on P12 to P14 and P15 presents a polymorphic beat sequence. The performances of the two methods are quasi equivalent. The correlation coefficients between the real ECGs and the synthesized ECGs, provided by the two methods, lie between: [0.95-0.99] for P1 to P11, [0.75-0.79] for P12 to P14 and equal to 0.94 for P15. The results suggest that the proposed non-linear ECG synthesis methods represent a promising approach to synthesize 12-lead ECG from only two EGMs, especially, the indirect method which provides a less time-consuming method that minimizes storage. ECG synthesis also offers an interesting alternative for remote monitoring systems for patients with implanted cardiac devices.

(Abstract Control Number: 86)