Optimum detection of myocardial infarctions with an intracavitary probe

Small myocardial infarctions (MI) may be life threatening, but cannot be easily detected using standard, body surface electrocardiography. This model study explores the use of an intracavitary probe to detect small MI's. The likelihood ratio is used for detection because it is optimum for most optimality criteria. A new quasi-static electromagnetic model of MI is presented which preserves the essential geometric features, while affording relatively fast numerical solutions. A tabulation of simulated results shows that an intracavitary probe can detect infarcts as small as 400 mm2 in 1 mV of noise with a detectability index of 0.495. (The detectability index is a measure of detection performance between 0.0 and 0.5, where 0.5 indicates perfect detection.) Simulations are presented for a variety of noise sources, infarction sizes, and probe designs.