EVALUATION OF QRST ISOINTEGRAL MAPS IN DETECTING POSTERIOR MYOCARDIAL-INFARCTION WITH AND WITHOUT CONDUCTION DISTURBANCE

We investigated the usefulness of QRST isointegral maps (I-maps) for d etecting posterior myocardial infarction (MI) with and without conduct ion disturbance. The I-maps were recorded during sinus rhythm and righ t ventricular (RV) pacing, which simulated left bundle-branch block (L BBB) in 19 patients with and in 20 patients without MI. Data on 608 no rmal subjects were used as controls. The ''-2 SD area'' where the QRST integral value was less than the lower limit of the normal range, was assessed by Sigma DM (sum of QRST integral values below the normal ra nge). Posterior MI was diagnosed with a sensitivity of 84%, a specific ity of 90%, and a diagnostic accuracy of 87%, assuming that MI was pre sent if Sigma DM exceeded 50 m V ms. During simulated LBBB, when the c riterion Sigma DM more than 250 m V ms was used, the sensitivity, spec i- ficity, and diagnostic accuracy were 79, 75, and 77%, respectively. Thus, I-maps may be useful in detecting posterior MI in patients with and without an intraventricular conduction disturbance.