Beatrice HENDERSON, Petitioner, v. The TRAVELERS INSURANCE COMPANY, Respondent, 544 S.W.2d 649

McGEE, Justice. This is a suit brought by Mrs. Beatrice Henderson for death benefits under the workmen’s compensation law. Her husband died of a heart attack on the employer’s premises soon after a workday had ended. The trial court instructed a verdict for the defendant at the close of the plaintiff’s evidence. The court of civil appeals affirmed. 533 S.W.2d 407. We reverse the judgment of the court of civil appeals and remand the case to the trial court. It was stipulated that Owen Henderson died at the Texaco Port Arthur Refinery after having worked his regular shift.

The evidence reveals that on January 16, 1973 Henderson arrived on the job at 7:30 in the morning. It was also shown that Henderson operated an air hoist or air tugger. An “air tugger” was described as a winch which is powered by pressurized air. The function of the air tugger was to hoist materials and equipment up to laborers working on various levels of a building under repair by utilization of a cable and pulley system. It was Henderson’s job to remain at the bottom of the structure under repair to operate the air tugger, raising and lowering materials as necessary.

It was shortly after Henderson had worked his full shift on January 16,1973 that he suffered a heart attack on the employer’s premises and died. Petitioner’s position is to the effect that the trial court erred in granting defendant’s motion for an instructed verdict because the evidence raised fact issues which required submission to a jury. Conversely, the respondents contend that an instructed verdict was proper because there was no evidence that Henderson suffered any kind of strain; nor was there any medical evidence offered that strain of any kind precipitated Henderson’s heart attack.

In an instructed verdict case, our task is to determine whether there is any evidence of probative force to raise fact issues on the material questions presented. Upon review, we must consider all of the evidence in its most favorable light in support of the plaintiff’s position and discard all contrary evidence and inferences. Anderson v. Moore, 448 S.W.2d 105 (Tex.1969); Triangle Motors of Dallas v. Richmond, 152 Tex. 354, 258 S.W.2d 60 (1953). When reasonable men may differ as to the truth of controlling facts, a jury issue is present. Najera v.

Great Atlantic & Pacific Tea Co., 146 Tex. 367, 207 S.W.2d 365 (1948). See, 3 McDonald, Texas Civil Practice, Sec. 11.28.2 (1970). The workmen’s compensation law does not provide for health insurance but is purposefully designed to compensate an employee for incapacity flowing from an accidental personal injury while engaged in the performance of his employment. As was stated in Whitaker v. General Insurance Co. of America, 461 S.W.2d 148, 151 (Tex.Civ.App. — Dallas 1970, writ ref’d n. r. e.): “The mere fact that an employee dies while on the premises of his employer, and during working hours,' is not sufficient.

It is incumbent upon one seeking to recover death benefits under the law to prove that the deceased sustained an injury which caused or contributed to cause the death.” However, in Baird v. T. E. I. A., 495 S.W.2d 207, 211 (Tex.1973), this court recently reaffirmed that a heart attack caused by strain or over-exertion is an accidental injury to the physical structure of the body within the meaning of the Workmen’s Compensation Act.

With reference to the causal connection required to be established between the exertion and the heart attack, the court in Baird went on to conclude that “. in the very nature of these cases, the evidence is most often largely circumstantial or based on answers by medical witnesses to hypothetical questions.” The crucial evidence produced in the case now before us when viewed in the light most favorable to the plaintiff is substantially as follows:. Deposition testimony of Henderson’s supervisor, Joseph Dawson, established Henderson’s work activities on the day in question. Dawson testified: “Q What was Mr.

Henderson’s job? “A He was running an air hoist or air tugger.” “Q Okay. Now, what time of day did Mr. Henderson come to work that morning? “A He was there at 7:30. “Q All right, he began his regular shift? “A At 7:30.” “Q Mr. Dawson, did Mr. Henderson work at this job as operating that air tugger all during the day, that is, eight hours of his shift on the day he died? “A Yes, sir, that was his primary job.” Donald LeBlanc, a co-worker with Mr.

Henderson, testified by deposition as to the normal duties of an “air tugger operator.” LeBlanc had not worked with Henderson on the day of Henderson’s death, but he had operated an air tugger on numerous occasions. LeBlanc testified as follows: “Q Assume with me that Mr. Henderson was working this job of operating the air tugger by himself. Is it a physically strenuous or demanding job? “A Definitely so. Most of the time you are working around people and your loads could be endangering the people that you’re working around if you’re not real careful what you’re doing. . . .

You’ve got to listen to the whoops and hollers, and we’ve got certain signals for up and down or hold it. And there’s a bunch of people and everybody hollering, and so you can’t really see actually where your load is. "Q How about just the physical strain, that is, whether you have to pull or push or use your muscles any? “A If you’re just running a lever, no. But that ain’t all there is to running an air tugger. You’ve got to pull cable, keep it straight, and like I say, I’ve seen very few times when people have sat down and run an air tugger.

It’s very few and far between. “Q How about just moving around; do you have to do a good bit of moving from one place to another? “A Every move you make, every time you let off on that air tugger, you’ve got to move to the front and pull it. “Q Is that something you can do just kind of leisurely . . .? “A Well, you’ve got people hollering at you all the time and the bosses, and also you know that someone is going to be in a strain if you don’t go up or come down on the other end, so you are usually moving pretty good on an air tugger. “Q How about any mental strain or mental pressure; is there any of that on that particular job? “A Again, it depends on the type of work you’re doing.

Personally, a lot of times, there’s a lot of mental strain because you are working with people and real close, and the wrong move could hurt someone.” “A So you are worried about somebody being under you at all times. Sure, it’s a strain, unless you’re just picking up a bucket or something when no one is around. But it is definitely a strain. “Q Can you work at your own pace and at your own speed in doing the job that Mr. Henderson was doing or not? “A Well, if you’re running an air tug-ger, sometimes you may make three lifts a day, but most of the time it’s continually up and down all the time.

And when the people flag you to get up, you get up. And when they flag you to get down and pull up slack, you go to the front and you pull slack.” We believe there is at least some evidence presented which raises an issue as to whether or not Henderson suffered any strain or exertion while at work. However, an additional aspect of this type of action which must now be considered is whether there is any evidence in this record which would raise a fact issue as to whether or not any strain or exertion suffered by Henderson was a producing cause of his heart attack. Dr.

Gwynne performed an autopsy on Henderson on January 17, 1973. The doctor indicated that Henderson had an enlarged left ventricle and Dr. Gwynne further testified by deposition in the following fashion: “Q Doctor, assume that the history that you got second hand about Mr. Henderson’s death and the circumstances surrounding it was correct, and then taking into account your autopsy and the findings, do you have an opinion based upon reasonable medical probability as to what the immediate cause of Mr.

Henderson’s death was, medically speaking? “A I have an opinion as to the most probable cause of death in this case. “Q All right, sir. “A As I indicated in my report to the Judge and in my completed protocol, I feel the most probable cause of death was cardiac arrhythmia, irregularity in the action of the heart, producing inadequate flow of blood to the heart itself and to other vital organs; this cardiac arrhythmia resulting from insufficient blood supply and consequently insufficient oxygen supply to the muscle of the heart, . . .

This reduction in blood flow to the muscle of the heart would be more likely in the presence of an enlarged left ventricle, a left ventricle enlarged because of high blood pressure, which commonly occurs in high blood pressure.

Although I don’t have a record of the man’s blood pressure, this would be likely — high blood pressure would be likely in a man with nodular hyper-plasia of the adrenal cortices, as I described in my protocol. “Q What is the exact relationship between physical exertion then and this heart arrhythmia, or how does physical exertion get us to heart arrhythmia? “A [I]f we have a man with a borderline blood supply to his heart, and then he exerts himself, maybe just a little bit, you see, and then his heart needs to speed up and needs to work harder. ...

Then from having barely enough, he goes to having not quite enough, and then that can precipitate this sort of thing, and will be associated with the development of a thrombus and myocardial infarction, or an occlusion, a functional or a myocardial occlusion. “Q How about the arrhythmic situation here? “A As I say, under conditions of increased need for oxygen in the poorly supplied myocardium, they can go from barely enough oxygen and nutrients getting to the heart to not quite enough, and then the not quite enough can produce a fatal cardiac arrhythmia, which I think is probably what happened here.” See, Insurance Company of North America v.

Kneten, 440 S.W.2d 52, 54 (Tex.1969). Additionally, the pertinent deposition testimony of Dr. Joe Alex DeLeon, a cardiologist, was subsequently read into the record. Dr.

DeLeon was asked to give his opinion about the cause of death and he responded as follows: “Q Assume for the purpose of the question further that operating the air hoist and greasing the bolts were things which did not involve great physical stress, but did involve a moderate amount of physical movement or moving around — and again getting back to my question of defining a ‘producing cause’ as simply being one of the things however many there may have been that brought about the event.

Then, in your opinion would the physical activity prior to his death have been one of the or a producing cause of his death in your judgment? “A Yes, sir, it could be. “Q All right, sir. Is that based on reasonable medical probability? “A Yes, sir, to the best of my knowledge.” On cross-examination, Dr. DeLeon stated that “[gjenerally speaking most people die either from physical activity or work —tennis, working out or doing other enjoyable things. ...

So, that if the man had been working, this could have produced his enlarged myocardium which could have led to sudden arrhythmia and sudden death.” We believe that this is some evidence that the heart attack was caused by Henderson’s strenuous work on the day of his death. It was revealed that Henderson had suffered a prior on-the-job injury in 1969. Because of the injuries sustained at that time, Henderson was placed on “light” or “restricted duty” by his employer.

However, Donald LeBlanc, who was Henderson’s coworker, was asked the question as to whether or not Texaco considered the operation of an air tugger to be a “light duty” job. In responding, LeBlanc stated: “Definitely not, not all air tuggers.” The cases which respondents rely most heavily upon are Olson v. Hartford Accident & Indemnity Company, 477 S.W.2d 859 (Tex.1972), and Whitaker v. General Insurance Company of America, 461 S.W.2d 148 (Tex.Civ.App. — Dallas 1970, writ ref’d n. r. e.). However, we do not find those authorities controlling of the present controversy.

In Olson, the facts revealed that the plaintiff did not perform any manual labor to speak of and previous to his heart attack, the plaintiff was not subjected to any particular physical strain or over-exertion. Further, recovery was sought under the theory that the plaintiff had suffered three or four irritating and frustrating job experiences over a 19-day period which together allegedly precipitated the heart attack (i. e. mental stimuli). Finally, the court noted that no attempt was made to connect any one of the frustrating experiences to the heart attack suffered by the plaintiff. Olson, supra at 859.

Such is obviously not the same situation as the one now before us. As for the court of civil appeals decision in Whitaker, we also regard it as being clearly distinguishable from the instant case. In Whitaker the court upheld the trial court’s action sustaining the insurance company’s motion for judgment non obstante veredicto. The court held that there was no evidence to support a jury finding that the heart attack the plaintiff had suffered was an injury sustained in the course of his employment and that such injury was a producing cause of plaintiff’s death.

In reaching its decision, the court reviewed the following testimony elicited from an individual who worked with Whitaker on the day of his death: “Q. All right. Were you there at all times except for your lunch hour? “A. Yes, sir, I was. “Q. During that time that you were there, both morning and afternoon, did he (Whitaker) ever do anything strenuous, such as change a tire? “A. No, sir.” The plaintiff in Whitaker had suffered an earlier heart attack a few months prior to his going to work at the gas station. Dr.

Markowitz, after testifying concerning his treatment of Whitaker for the previous heart condition and attack, and based upon a hypothetical question concerning the activity engaged in by Whitaker at the service station, was asked to state whether or not the man simply suffered another attack or whether he might have suffered an injury which caused an attack. The doctor stated that there was no way to give such an opinion. He testified that without an autopsy he was not 100 percent sure that the second attack killed Whitaker but he would have to assume that he died of a heart attack.

The court of civil appeals also found that other medical testimony elicited was improperly based upon facts not in the record. Under the record in Whitaker, the court concluded that there was no evidence of probative force that Mr. Whitaker was called on to perform any work that required strenuous exertion or strain. The court announced that the limited medical testimony offered by the plaintiff was too speculative to constitute probative evidence and upheld the trial court’s judgment non obstante veredicto.

Again, we believe the fact situation presented in Whitaker to be substantially different from the situation presently before us. We find that the other eases relied upon by the respondents are similarly distinguishable. In conclusion, it is always difficult in this type of case to answer the problem of whether the evidence, most often circumstantial, and the inferences drawn therefrom, present issuable facts. “There is no precise rule to measure probative force and by which to decide if questions of fact are raised by the evidence.” Baird v. T. E. I. A., 495 S.W.2d 207, 211 (Tex.1973).

In the case now under consideration, it was revealed that Henderson had worked a full shift doing a job that could often be strenuous in nature. We have testimony from the doctor who actually performed the autopsy on Henderson to the effect that the cause of death was, in his opinion, cardiac arrhythmia. This medical testimony was further substantiated by Dr. DeLeon. As a result, givehjthis record, we cannot say that the evidence offered to prove the vital facts is so weak as to do no more than create a mere surmise or suspicion of their existence. See, Seideneck v.

Cal Bayreuther Associates, 451 S.W.2d 752, 755 (Tex.1970); Joske v. Irvine, 91 Tex. 574, 44 S.W. 1059 (1898); Calvert, “No Evidence” and “Insufficient Evidence” Point of Error, 38 Texas L.Rev. 361 (1960). We hold that the circumstances thus shown by the evidence are such as to call for a factual determination of whether Henderson suffered an injury in the course of his employment, and, if so, whether such was a producing cause of his death. Accordingly, we reverse the judgment of the court of civil appeals and remand this cause to the trial court. Concurring opinion by REAVLEY, J., in which STEAKLEY, J., joins.

Dissenting opinion by GREENHILL, C. J., in which DENTON, J., joins. . It should be noted at this point that it is not required that the injury in the course of employment be the sole cause of disability or death, and that a predisposing bodily infirmity will not preclude compensation. See, Texas Indemnity Ins. Co. v. Staggs, 134 Tex. 318, 134 S.W.2d 1026 (1940).