1. 1. The resulting condition of an employee who:

   1. (a) Has a preexisting condition from a cause or origin that did not arise out of or in the course of the employee’s current or past employment; and

   2. (b) Subsequently sustains an injury by accident arising out of and in the course of his or her employment which aggravates, precipitates or accelerates the preexisting condition,

      shall be deemed to be an injury by accident that is compensable pursuant to the provisions of chapters 616A to 616D, inclusive, of NRS, unless the insurer can prove by a preponderance of the evidence that the subsequent injury is not a substantial contributing cause of the resulting condition.

2. 2. The resulting condition of an employee who:

   1. (a) Sustains an injury by accident arising out of and in the course of his or her employment; and

   2. (b) Subsequently aggravates, precipitates or accelerates the injury in a manner that does not arise out of and in the course of his or her employment,

      shall be deemed to be an injury by accident that is compensable pursuant to the provisions of chapters 616A to 616D, inclusive, of NRS, unless the insurer can prove by a preponderance of the evidence that the injury described in paragraph (a) is not a substantial contributing cause of the resulting condition.

(Added to NRS by 1993, 663; A 1995, 2147; 1999, 1777)