BACKGROUND The aim of this prospective study was to investigate the concordance between quantitative resting (201)Tl uptake as an established myocardial viability index and the electrical activity of the heart, determined by NOGA nonfluoroscopic electroanatomic mapping. METHODS AND RESULTS The myocardial resting and late resting thallium uptakes of 384 myocardial segments from 32 patients (27...