| | Summary
of the Neurophysiology of Angina Pectoris
Sensory input from the heart excites spinothalamic tract cells in
the thoracic and upper cervical segments of the spinal cord. These
cells receive convergent input from the overlying somatic structures.
Thus, this information forms the basis for understanding the pain
resulting from ischemic heart disease.
However, the
huge variations in the expression of pain of overlying somatic
structures, and particularly in episodes of cardiac ischemia in
which no pain occurs (so-called silent ischemia), raise important
questions about how cardiac sensory information is processed,
modulated, and perceived. These variations could occur in structures
previously mentioned, such as the dorsal root ganglia, spinal
gray matter, brain stem, and cerebral cortex. They might also
occur in the peripheral intrinsic and extrinsic cardiac ganglia,
which contain neurons that do not project to the spinal cord but
can influence sensory and motor autonomic neurotransmission.
Future studies
should explore the hierarchy of control mechanisms that integrate
the activity from these regions and ultimately cause the various
manifestations of the sensation of angina pectoris.
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