Noninvasive electrocardiographic imaging of substrate and intramural ventricular tachycardia in infarcted hearts

OBJECTIVES The goal of this study was to experimentally evaluate a novel no ninvasive electrocardiographic imaging modality during intramural reentrant ventricular tachycardia (VT). BACKGROUND Myocardial infarction and subsequent remodeling produce abnormal electrophysiologic substrates capable of initiating and maintaining reentr ant arrhythmias. Existing noninvasive electrocardiographic methods cannot c haracterize abnormal electrophysiologic substrates in the heart or the deta ils of associated arrhythmias. A noninvasive method with such capabilities is needed to identify patients at risk of arrhythmias and to guide and eval uate therapy. METHODS A dog heart with a four-day-old infarction was suspended in a human shaped torso-tank. Measured body surface potentials were used to noninvasi vely compute epicardial potentials, electrograms and isochrones. Accuracy o f reconstruction was evaluated by direct comparison to measured data. Recon structions were performed during right atrial pacing and nine cycles of VT. RESULTS Noninvasively reconstructed potential maps, electrograms and isochr ones identified: 1) the location of electrophysiologically abnormal infarct substrate; 2) the epicardial activation sequences during the VTs; 3) the l ocations of epicardial breakthrough sites; and 4) electrophysiologic eviden ce for activation of the Purkinje system and septum during the reentrant be ats. CONCLUSIONS Electrocardiographic imaging can noninvasively reconstruct elec trophysiologic information on the epicardium during VT with intramural reen try, provide information about the location of the intramural components of reentry and image abnormal electrophysiologic substrates associated with i nfarction. (J Am Coll Cardiol 2001;38:2071-8) (C) 2001 by the American Coll ege of Cardiology.