Joseph Henry v. Dept of Corrections, 295 P.3d 528

Mr. Henry suffered a heart attack at work on November 15, 2009, leading to emergency treatment and subsequent bypass surgery.
Preexisting conditions (anxiety, hypertension, sleep apnea, hypercholesterolemia, smoking) and long-standing risk factors were noted.
Henry filed a workers’ compensation claim (April 2010) alleging the heart attack was industrially related and that his condition was aggravated by work.
The Industrial Commission found no causal link between work and the heart attack, adopting the referee’s conclusions.
The cardiologist testified the heart attack was caused by plaque rupture; he could not definitively determine whether triggers occurred before or after arrival at work.
The Commission concluded the cardiologist could not prove that post-arrival activities caused or triggered the heart attack; the court upheld the Commission’s decision.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Causation standard for industrial accident	Henry contends the Commission misapplied causation law by requiring sole causation by work.	Henry must show work-related triggering of the heart attack to a reasonable medical probability, not sole causation.	upheld; Commission did not require sole causation and reasonably found no work-triggered causation.
Cardiologist’s burden and credibility	Cardiologist testified work-related triggers could cause plaque rupture; his opinion should support causation.	The cardiologist could not pinpoint whether triggers occurred pre- or post-arrival; thus causation not proven.	affirmed; cardiologist’s uncertainty about timing precludes finding an industrial accident.
Weight of expert vs. lay observations	Referee improperly discounted Dr. Parent’s testimony by overemphasizing pre-arrival factors.	Referee appropriately weighed all evidence, including pre-arrival factors, to test causation.	affirmed; the court found the referee/Commission properly assessed medical evidence and credibility.

Horner v. Ponderosa Pine Logging, 107 Idaho 1111 (Idaho 1985) (establishes causation principle: aggravation/acceleration of preexisting condition may support benefits)
Spivey v. Novartis Seed Inc., 137 Idaho 29 (Idaho 2002) (preexisting infirmity does not bar recovery if employment aggravated injury)
Painter v. Potlatch Corp., 138 Idaho 309 (Idaho 2003) (aggravation of preexisting condition may constitute injury if precipitated by accident)
Stevens-McAtee v. Potlatch Corp., 145 Idaho 325 (Idaho 2008) (claimant must prove causal relationship to an employment accident by medical probability)
Eacret v. Clearwater Forest Indus., 136 Idaho 733 (Idaho 2002) (free review on law; substantial evidence standard for fact-finding)
Dravo Corp., 97 Idaho 158 (Idaho 1975) (probability-based medical causation; solid physician testimony can support causation)
Pierstorff v. Gray’s Auto Shop, 58 Idaho 438 (Idaho 1937) (principle that credible, unimpeached medical testimony may be controlling)