The Stomach 18 Point
  The stomach 18 point is located on the fifth intercostal nerve. Attacking this
  point can adversely affect the heart because the fifth  intercostal nerve
connects to the cardiac  sympathetic nerves in the
 spinal cord.
  Thus, stimulation  of this point can increase the sympathetic stimulation of
  the heart. In a susceptible individual this can lead to abnormal heart rhythms or a heart attack.
In addition, the left
  stomach 18 point lies directly over an area of the  chest
where blunt trauma is associated
  with sudden cardiac death. This phenomenon is called commotio cordis and is
  well documented in the medical literature.
intercostal nerve
connects to the cardiac  sympathetic nerves in the
 spinal cord.
  Thus, stimulation  of this point can increase the sympathetic stimulation of
  the heart. In a susceptible individual this can lead to abnormal heart rhythms or a heart attack.
In addition, the left
  stomach 18 point lies directly over an area of the  chest
where blunt trauma is associated
  with sudden cardiac death. This phenomenon is called commotio cordis and is
  well documented in the medical literature.