King v. Credit General Ins. Co. [11/10/99] 1999 MTWCC 72 WCC was not persuaded that work activities of over-the-road truck driver caused an arrhythmia leading to his death, but credited testimony indicating claimant died from longstanding "severe atherosclerotic disease." While the definition of accident includes an unusual strain, claimants failed to prove that death resulted from a specific event on a single day or during a single work shift as required by statute. Note: WCC affirmed on appeal, King v. Credit General, 2000 MT 260 ("the Kings did not meet their burden of establishing that Russell King's death was ‘caused by a specific event on a single day or during a single work shift' as required under section 39-71-119(2)(d), MCA (1993).")