ST-segment potentials and mapping. Theory and experiments.

Abstract

The physiological mechanism of [human] ST-segment deviation is complex, but the laws of electricity and electrophysiologic theory permit some understanding of the underlying cellular events. The value of understanding the basic mechanism in interpreting ST-segment mapping and other clinical measurements should not be underestimated. No exact correlation of ST-segment change with ischemia should be expected, because the mechanisms involve interaction between normal and abnormal tissue. Any factor influencing membrane properties in either area will alter the ST segments, regardless of its influence on ischemia. Consequently, inferences from the extent or magnitude of ST changes overlying an area of ischemia may be misleading and ST-segment mapping should not be used as an independent measure of ischemia. Since ST-segment deviation indicates abnormal current flow in the heart, it may be an important factor for other reasons, for example, in producing lethal arrhythmias. Further studies of this possibility may be helpful in understanding or treating these important complications of ischemia.