Endocardial fragmented electrogram and prediction of ventricular tachycardia by body surface signal-averaged electrocardiographic mapping.

Signal-averaged (SA) electrocardiography and SA electrocardiographic mapping were performed in 50 patients with old myocardial infarction, 19 of whom had left ventricular aneurysm and 11 of whom had clinical sustained ventricular tachycardia. The SA electrocardiogram and SA electrocardiographic mapping data were then compared with those obtained by endocardial catheter mapping in patients with or without fragmented electrograms, sustained ventricular tachycardia, and ventricular aneurysm. Compared to SA electrocardiography, the SA map correlates with sustained VT with improved sensitivity but decreased specificity. However, SA electrocardiographic mapping had the advantage of displaying the extent of the body surface area that was positive for late potentials. In addition, the site of the longest endocardial fragmented electrogram could be predicted by SA electrocardiographic mapping, suggesting that this technique deserves wider clinical application.