Disclosed is a
system for detecting pathophysiological cardiac conditions from a reduced number of extracardiac leads. A right side lead measures the electrical
signal between the middle superior
chest region over the heart and inferior right
torso position. A left side lead measures the electrical
signal between the left precordial
chest region and an inferior left lateral or posterior
torso position. The lead montage is preferably chosen so that, regardless of patient position (e.g. supine, upright), negative ST segments and / or T
waves are used to detect right coronary or left
circumflex ischemia. Also, in these positions, reduced slope of the final deflection in the QRS can be used to detect these types of
ischemia. To detect transmural
ischemia, the
system examines changes in QRS slopes,
ST segment,
T wave and the difference between the J point and the PQ potentials. In addition, for transmural ischemia associated with the left anterior descending
artery, a proxy for the
propagation time across the front of the heart is examined by comparing QRS features of the right side lead with QRS features of the left side lead.
Histogram profiles, trends, and statistical summaries, especially running averages, of all of the above mentioned features, corrected for
heart rate, are maintained.