A. A heart-related or perivascular injury, illness or death shall not be considered a personal injury by accident arising out of and in the course of employment and is not compensable pursuant to this chapter unless some injury, stress or exertion related to the employment was a substantial contributing cause of the heart-related or perivascular injury, illness or death.
B. A mental injury, illness or condition shall not be considered a personal injury by accident arising out of and in the course of employment and is not compensable pursuant to this chapter unless some unexpected, unusual or extraordinary stress related to the employment or some physical injury related to the employment was a substantial contributing cause of the mental injury, illness or condition.
C. If compensation is payable for a heart-related or perivascular injury, illness or death, or for a mental injury, illness or condition, the only employer liable is the employee's last employer in whose employment the requirements of subsection A or B are met.