Early diagnosis of right ventricular or posterior infarction associated with inferior wall left ventricular acute myocardial infarction

Right ventricular (RV) or posterior infarction associated with inferior wal l left ventricular acute myocardial infarction (AMI) has important therapeu tic and prognostic implications. However, RV and posterior chest leads in a ddition to the 12-lead electrocardiogram are required for accurate detectio n. Body surface mapping (BSM) has greater spatial sampling and may further improve inferior wall AMI classification. Consecutive patients with chest p ain lasting <12 hours were assessed to identify those with AMI and greater than or equal to 0.1 mV ST elevation in greater than or equal to 2 contiguo us inferior leads of the 12-lead electrocardiogram (bundle branch block or left ventricular hypertrophy excluded), A 12-lead electrocardiogram, RV lea ds (V2R, V4R), posterior chest leads (V-7, V-9) and a BSM were recorded, Fr om each BSM, the 12 electrodes overlying the RV region (regional RV map) an d 10 electrodes overlying the posterior wall (regional posterior map) were assessed for ST elevation. Infarct size wets estimated by serial cardiac en zymes. AMI occurred in 173 of 479 patients. Of the 62 patients with inferio r wall AMI, ST elevation greater than or equal to 0.1 mV occurred in 26 pat ients (42%) in V2R or V4R compared with 36 patients (58%) in greater than o r equal to 1 electrode on the regional RV map (p = 0.0019), ST elevation gr eater than or equal to 0.1 mV occurred in 1 patient (2%) in V-7 Or V-9 comp ared with 17 patients (27%) in greater than or equal to 1 electrode on the regional posterior map (p = 0.00003), ST elevation) greater than or equal t o 0.05 mV occurred in 6 patients (10%) in V-7 Or V-9 compared with 22 patie nts (36%) in greater than or equal to 1 electrode on the regional posterior map (p = 0.00003), patients with ST elevation on regional RV and/or poster ior maps had ct trend toward larger infarct size (mean peak creatine kinase 1,789 +/- 226 vs 1,546 +/- 392 mmol/L; p = NS), Thus, BSM, when compared w ith RV or posterior chest leads, provides improved classification of patien ts with inferior wall AMI and RV or posterior wall involvement. (C) 2000 by Excerpta Medico, Inc.