COBEY, Acting P. J.

 These are appeals by Jonathan Earl Stamp, Michael John Koory and Billy Dean Lehman, following jury verdicts of guilty of robbery and murder, both in the first degree. Each man was given a life sentence on the murder charge together with the time prescribed by law on the robbery count.

 Defendants appeal their conviction of the murder of Carl Honeyman who, suffering from a heart disease, died between 15 and 20 minutes after Koory and Stamp held up his business, the General Amusement Company, on October 26, 1965, at 10:45 a.m. Lehman, the driver of the getaway car, was apprehended a few minutes after the robbery; several weeks later Stamp was arrested in Ohio and Koory in Nebraska.

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 On this appeal appellants primarily rely upon their position that the felony- murder doctrine should not have been applied in this case due to the unforeseeability of Honeyman's death.

The Facts

 Defendants Koory and Stamp, armed with a gun and a blackjack, entered the rear of the building housing the offices of General Amusement *208  Company, ordered the employees they found there to go to the front of the premises, where the two secretaries were working. Stamp, the one with the gun, then went into the office of Carl Honeyman, the owner and manager. Thereupon Honeyman, looking very frightened and pale, emerged from the office in a "kind of hurry." He was apparently propelled by Stamp who had hold of him by an elbow.

 The robbery victims were required to lie down on the floor while the robbers took the money and fled out the back door. As the robbers, who had been on the premises 10 to 15 minutes, were leaving, they told the victims to remain on the floor for five minutes so that no one would "get hurt."

 Honeyman, who had been lying next to the counter, had to use it to steady himself in getting up off the floor. Still pale, he was short of breath, sucking air, and pounding and rubbing his chest. As he walked down the hall, in an unsteady manner, still breathing hard and rubbing his chest, he said he was having trouble "keeping the pounding down inside" and that his heart was "pumping too fast for him." A few minutes later, although still looking very upset, shaking, wiping his forehead and rubbing his chest, he was able to walk in a steady manner into an employee's office. When the police arrived, almost immediately thereafter, he told them he was not feeling very well and that he had a pain in his chest. About two minutes later, which was 15 or 20 minutes after the robbery had occurred, he collapsed on the floor. At 11:25 he was pronounced dead on arrival at the hospital. The coroner's report listed the immediate cause of death as heart attack.

 The employees noted that during the hours before the robbery Honeyman had appeared to be in normal health and good spirits. The victim was an obese, 60- year-old man, with a history of heart disease, who was under a great deal of pressure due to the intensely competitive nature of his business. Additionally, he did not take good care of his heart.

 Three doctors, including the autopsy surgeon, Honeyman's physician, and a professor of cardiology from U.C.L.A., testified that although Honeyman had an advanced case of atherosclerosis, a progressive and ultimately fatal disease, there must have been some immediate upset to his system which precipitated the attack. It was their conclusion in response to a hypothetical question that but for the robbery there would have been no fatal seizure at that time. The fright induced by the robbery was too much of a shock to Honeyman's system. There was opposing expert testimony to the effect that it could not be said with reasonable medical certainty that fright could ever be fatal. *209

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Application of the Felony-murder Rule

 Appellant's contention that the felony-murder rule is inapplicable to the facts of this case is . . . without merit. Under the felony-murder rule of section 189 of the Penal Code, a killing committed in either the perpetration of or an attempt to perpetrate robbery is murder of the first degree. This is true whether the killing is wilfull, deliberate and premeditated, or merely accidental or unintentional, and whether or not the killing is planned as a part of the commission of the robbery. . . .

 The doctrine presumes malice aforethought on the basis of the commission of a felony inherently dangerous to human life. [n. 3]
 

3 . . . . This rule is a rule of substantive law in California and not merely an evidentiary shortcut to finding malice as it withdraws from the jury the requirement that they find either express malice or the implied malice which is manifested in an intent to kill. (People v. Lilliock, 265 Cal.App.2d 419, 431 [71 Cal.Rptr. 434].) Under this rule no intentional act is necessary other than the attempt to or the actual commission of the robbery itself. When a robber enters a place with a deadly weapon with the intent to commit robbery, malice is shown by the nature of the crime.

 There is no requirement that the killing occur, "while committing" or  "while engaged in" the felony, or that the killing be "a part of" the felony, other than that the few acts be a part of one continuous transaction. (People v. Chavez, 37 Cal.2d 656, 670 [234 P.2d 632].) Thus the homicide need not have been committed "to perpetrate" the felony. There need be no technical inquiry as to whether there has been a completion or abandonment of or desistance from the robbery before the homicide itself was completed. ( People v. Chavez, supra, at pp. 669-670.)

 The doctrine is not limited to those deaths which are foreseeable.  (See 1 Witkin, Cal. Crimes (1963) §§ 78, 79, pp. 79-80; People v. Chavez, supra, at pp. 669-670.) Rather a felon is held strictly liable for all killings committed by him or his accomplices in the course of the felony. (People v. Talbot, 64 Cal.2d 691, 704 [51 Cal.Rptr. 417, 414 P.2d 633].) As long as the homicide is the direct causal result of the robbery the felony-murder rule applies whether or not the death was a natural or probable consequence of the robbery. So long as a victim's predisposing physical condition, regardless of its cause, is not the only substantial factor bringing about his death, that condition, and the robber's ignorance of it, in no way destroys the robber's criminal responsibility for the death. (Cf. People v. *211 Moan, 65 Cal. 532, 536-537 [4 P. 545]; People v. Studer, 59 Cal.App. 547, 552-554 [211 P. 233].) So long as life is shortened as a result of the felonious act, it does not matter that the victim might have died soon anyway. ( People v. Phillips, supra, at p. 579.) In this respect, the robber takes his victim as he finds him.

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 Appellants contend that the trial court erred in refusing their proffered instruction on proximate cause, reading as follows: "Where the defendant's criminal act is not the proximate cause of the death and the sole proximate cause was the negligent or reckless conduct of the victim, a conviction is unwarranted." They assert that article VI, section 13 of the California Constitution guarantees the right of a defendant to have the jury determine every material issue presented by the evidence.

 In can be argued that the refusal of the trial court to give the instruction was justified. The evidence before the jury was not such that the jury could have reasonably assumed that negligent or reckless conduct by Honeyman was-the sole cause of his death. (See People v. Bronson, 263 Cal.App.2d 831, 842- 843 [70 Cal.Rptr. 162], hear. den.) But, in any event, the three instructions given on the issue of the proximate causation of Honeyman's death were much more complete and accurate than appellant's quoted instruction. Any error in this respect was harmless. *212

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 The judgment is affirmed.