Assessment of Heart Repolarization Properties from Body Surface Potential Maps

Use of activation-recovery interval (ARI) in surface ECG leads as possible indicator of changed repolarization in the underlying myocardium was studied. Model ECG data representing normal and pathological myocardium repolarization were simulated on surface of realistic inhomogeneous torso. Results of simulations suggest that shortening and prolongation of action potentials in anterior myocardial regions representing more than 6% of the heart volume can be visible in surface ARI maps while only prolongation in postero-lateral regions can be observed. Reproducibility of ARI was checked on real measurements using 32 to 192 ECG leads. Obtained ARI maps exhibited good intra-individual stability with correlation 0.89 to 0.94. From the model and experimental results it has been concluded that analysis of ARI may give some insight into the myocardium repolarization and can help to recognize tissue with changed properties namely in heart regions underlying the anterior chest.