dissenting: This court is committed to the proposition that a claimant in a workmen’s compensation case must prove his claim by substantial competent evidence, and where the district court, after reviewing the transcript, makes an award based upon findings of fact, these findings must be supported by substantial competent evidence, not surmise or conjecture. (McMillan v. Kansas Power & Light Co., 157 Kan. 385, 139 P. 2d 854; Jones v. Lozier-Broderick & Gordon, 160 Kan. 191, 160 P. 2d 932; and Copenhaver v. Sykes, 160 Kan. 238, 160 P. 2d 235.)
In this case the district court found by adoption of the commissioner’s findings of fact that the decedent’s death resulted from *806“injury . . . arising out of . . . his employment being the aggravation of a pre-existing condition.” (Emphasis added.)
The decision hinges on whether there was substantial competent evidence to show the decedent’s injury arose out of his employment.
The expert medical opinion of two doctors was presented at the trial. Dr. Wood testifying for the appellants supplied no evidence which could be of assistance to the appellee. The other was the appellee’s witness, Dr. Sabo. On direct examination his opinion based upon reasonable medical probability was that the duties which the decedent performed on tire morning of his accident could have contributed to or caused the coronary infarction which occurred. He also testified on direct examination:
“It is a known fact that strenuous exercise, irregardless of what it may be: lifting your arms or shoveling or whatever may be done by the individual, that because of this strenuous exercise it increases the circulation and could precipitate an attack of this type.” (Emphasis added.)
On this point see, Whitaker v. Panhandle Eastern P. L. Co., 142 Kan. 314, 46 P. 2d 862.
On cross examination, however, Dr. Sabo was closely examined in accordance with the appellants’ theory of a coronary occlusion caused by thrombosis. This theory is described in detail in Rorabaugh v. General Mills, 187 Kan. 863, 356 P. 2d 796. There this court recognized, in sustaining the decision of the trial court denying compensation, that the opinion of an expert must be based upon probability and not mere possibility to meet the requirement of substantial competent evidence.
On cross examination of Dr. Sabo it was disclosed that he had been the decedent’s doctor since 1952, and that there was nothing in his records to indicate the decedent was having any coronary difficulties prior to the date of his “attack” on February 28, 1959. He readily conceded this “attack” was caused by thrombosis. In accordance with the theory propounded by the appellants, Dr. Sabo recognized there was nothing known to medical science to indicate that work, effort, labor or exercise caused a thrombosis to form. Thus, since the infarction results from the thrombosis, the pre-existing condition to be aggravated by the decedent’s work was necessarily the existence of a thrombosis blocking the coronary artery. He readily conceded until there was a thrombosis there was no condition to be aggravated by the work. The following is his testimony on cross examination:
*807“Q. The problem comes, doesn’t it, Doctor, that after that thrombus is formed, if the man is performing labor that creates a greater demand for blood supply to his heart, why, the thrombus is keeping that blood supply from getting there, isn’t that true?
“A. That is correct.” (Emphasis added.)
From the testimony o£ Dr. Sabo it is clear the decedent’s work could have aggravated a pre-existing condition only if the thrombosis existed prior to the time the decedent stopped working. Yet, on cross examination the best opinion of the claimant’s doctor was that the decedent’s thrombosis built up to a sufficient point to cut off blood so as to begin to bother the decedent at the time the decedent got out of his chair and told his fellow workman he was going to faint — a time approximately thirty minutes after the decedent stopped working. Dr. Sabo then admitted the conclusion that followed inevitably:
“Q. . . . Now, Doctor, if that is the case, and Mr. Burns’ thrombus came at the time after he had been sitting in the office for some thirty minutes, and that thrombus hit him then and cut off his blood supply to a critical amount, to where he got up and said he was going to faint and did and had to be brought to the hospital, then there isn’t any way that work caused the infarction that followed that thrombus, was there?
“A. Not necessarily, no, that is correct.”
After redirect examination by claimant’s counsel Dr. Sabo again admitted on recross examination that he did not know how long the decedent had the thrombus prior to the attack that occurred inside the shop, if he had the thrombus prior to that time at all. Dr. Sabo said he had “no opinion” as to whether the decedent could have had the thrombus prior to that time.
The question posed is whether the district court’s finding is supported by substantial competent evidence where the only testimony in support thereof consists solely of a naked, conclusion on direct examination of claimant’s doctor, where such conclusion is not only unsupported by the same doctor’s testimony on cross examination, but actually contrary to his testimony on cross examination.
In my opinion Dr. Sabo’s testimony on cross examination canceled out the effect of his opinion given on direct examination. The sum and substance of his testimony was that there could be a causal relation between the work and the injury resulting in death, but such testimony does not sustain the burden of proof cast upon the claimant. This conclusion is not inconsistent with the line of cases holding that compensation is recoverable if the work is causally *808related to the “heart attack.” The question is one of proof where medical opinion testimony has been expressed and the relationship of cause and effect shown to exist.
For the foregoing reasons the judgment of the trial court, in my opinion, should be reversed.