The defendant was charged in a four-count information with first degree manslaughter, in violation of General Statutes § 53a-55 (a) (3), with second degree robbery, in violation of General Statutes § 53a-135 (a) (2), and with two counts of first degree unlawful restraint, in violation of General Statutes § 53a-95 (a). The defendant was convicted by a jury and, from the judgment rendered on the verdict, he has appealed claiming that the *229 trial court erred in certain of its instructions to the jury, in its denial of his request for instructions, in its charge concerning the elements of manslaughter under § 53a-55 (a) (3), in its denial of his motion to dismiss, and in its denial of his motion to set aside the verdict.
Prom a review of the evidence, the jury could have found the following: In the early afternoon hours of May 3,1974, Mr. and Mrs. Elwyn Murdock of Hamden, Connecticut, received a telephone call from the defendant, identifying himself as Dr. J. Merriwether, who inquired as to whether the Murdocks had antique jewelry and silverware for sale. The Murdocks used a portion of their residence for the sale of antiques by appointment, and arrangements were made for a visit that afternoon by the defendant. At approximately 4 p.m., the defendant arrived and, after viewing the Murdocks’ antiques, made arrangements to return later that evening with funds to purchase the items of antique silver that he had selected. During the conversation of that afternoon, Mrs. Murdock, thinking that the defendant was a medical doctor, informed him that her husband had retired to their home to conduct the antique business because of his health, that he had previously had four heart attacks, and that she was now working together with Mr. Murdock. The defendant replied that Mr. Murdock had been lucky so far. At about 9 p.m., the defendant returned and, after casual discussion over a eup of coffee with the Murdocks, drew Mr. Murdock aside and handed him a note informing him that he (the defendant) intended to rob Mr. Murdock. The defendant then forced the Murdocks down to the basement of their home, displaying what appeared to the Murdocks to be a handgun.
*230 Upon reaching the basement, the defendant produced from a briefcase two sets of handcuffs and some rope. He handcuffed Mrs. Murdock’s hands and tied her legs, forcing her to lie on her stomach on the basement floor. Mr. Murdock was similarly bound, but the defendant allowed him to lay face up on the floor. At this point, Mr. Murdock began to breathe very heavily and said to the defendant, “Please call a doctor. Pm having a heart attack.” After this plea had been repeated several times, the defendant propped up Mr. Murdock’s head with a vase; a doctor was never called, however. The defendant then left Mr. and Mrs. Murdock in the basement and proceeded through the house, taking several items of value, and approximately $300 in cash.
After the defendant left the house, Mr. Murdock again stated that he could not breathe and Mrs. Murdock, upon freeing herself, was able to summon an ambulance, which arrived within ten minutes. Mr. Murdock was given mouth-to-mouth cardiopulmonary resuscitation at the Murdocks’ residence, but appeared unresponsive. He was pronounced dead at the Yale-New Haven Hospital shortly after arrival. Medical testimony at trial established that the cause of Mr. Murdock’s death was a heart attack, brought on by the emotional stress resulting from the action of the defendant. Medical evidence further established that Mr. Murdock had suffered at least two previous heart attacks and was, on May 3, 1974, under a doctor’s care for his heart condition. An autopsy performed subsequent to Mr. Murdock’s death confirmed the testimony that he had had several prior heart attacks, leaving his heart in a weakened condition.
*231 At the outset, we note that the defendant testified at trial and conceded virtually all of the state’s case, with two exceptions, hereinafter to be discussed. Thus, the issues that merit our attention have, by virtue of the defendant’s testimony, been considerably narrowed. The defendant’s primary claim of error involves two related concepts. He claims that actual, direct physical injury is an element of the crime of manslaughter, as defined by General Statutes § 53a-55 (a) (3), 1 and, in relation to this, that the infliction of external physical injury upon a victim must be found before a causal relation between the defendant’s conduct and the victim’s death may be found to exist. Thus, the defendant argues, the trial court erred in its instruction to the jury concerning “proximate causation” in relationship to the defendant’s “conduct” under § 53a-55 (a) (3). The defendant appears to argue that since the cause of Murdock’s death was not a physical blow inflicted by the defendant, but rather a heart attack caused by the stress of the situation into which the defendant had placed Murdock, he could not, as a matter of law, be found to have “caused” Murdock’s death. We disagree.
It may have been the law at one time that there could be no culpable homicide that was not the result of some kind of corporal harm inflicted upon the victim. See, e.g.,
Regina
v.
Murton,
3 Fost.
&
Fin. 492, 176 Eng. Rep. 221 (1862). Today, however, almost all courts have rejected this view of criminal
*232
liability. See annot.,
The defendant’s claim that the trial court erred in instructing the jury on the meaning of “proximate cause” under General Statutes § 53a-55 (a) (3) is without merit. “Proximate cause” in the criminal law does not necessarily mean the last act of cause, or the act in point of time nearest to death. The concept of proximate cause incorporates the notion that an accused may be charged with a criminal
*234
offense even though his acts were not the immediate cause of death. An act or omission to act is the proximate cause of death when it substantially and materially contributes, in a natural and continuous sequence, unbroken by an efficient, intervening cause, to the resulting death. It is the cause without which the death would not have occurred and the predominating cause, the substantial factor, from which death follows as a natural, direct and immediate consequence. See
State
v.
Tomassi,
*236
The defendant next claims error in the trial court’s denial of his request to charge the jury as to the meaning of “extreme indifference to human life” under General Statutes § 53a-55 (a) (3) and in the court’s failure to define that term for the jury. No definition of “extreme indifference to human life” is found in title 53a (Penal Code) of the General Statutes. The court, however, charged the jury extensively on the meaning of “recklessly.” In this connection, the court instructed the jury as to the meaning of “extreme indifference to human life”: “Mere carelessness is not enough, nor is ordinary recklessness sufficient. The law here requires extreme indifference to human life.” Although the code does not define the term, the significance of the omission of an instruction on “extreme indifference to human life” under the code may be evaluated by a comparison with the instructions that were given. See
Henderson
v.
Kibbe,
The defendant next claims that the trial court’s charge, in toto, as to the elements of the crime of manslaughter in the first degree was inaccurate and confusing and that it thereby prejudicially misled the jury. We have already determined that the portion of the court’s charge with respect to proximate cause was clear and accurate. A review of the remainder of the charge indicates that it did not mislead the jury, nor was the charge confusing. Although there were certain deficiencies in the charge, any confusion that was thereby engendered was adequately cleared up by subsequent, supplemental instructions by the court. The trial court did not abuse its discretion in making reasonable comments on the evidence;
State
v.
Vincenzo,
Finally, the defendant makes a somewhat broadside “due process” attack on the trial court’s denial
*238
of his motion to dismiss certain counts of the information and the denial of his motion to set aside the verdict. Both motions had as their premise the assertion that the state did not produce evidence sufficient to sustain the jury verdict of guilty as to all counts of the information.
6
As we have previously stated, the defendant testified at trial and admitted almost all of the state’s case, with two exceptions. The defendant (1) denied that he was informed on the afternoon of the robbery that Murdock had a heart condition and (2) denied that Murdock told him that he (Murdock) was having a heart attack during the course of the robbery. Both of those facts bear on the defendant’s “indifference to human life” and his reckless engagement in “conduct which creates a grave risk of death to another person,” which elements the state is required to prove beyond a reasonable doubt under the manslaughter statute. By its verdict, the jury could reasonably have believed the state’s witness, Mrs. Murdock, and disbelieved the defendant’s version of the events surrounding the robbery. The credibility of witnesses is to be determined by the jury as trier of fact;
State
v.
Malley,
There is no error.
In this opinion the other judges concurred.
Notes
“ [General Statutes] See. 53a-55. manslaughter in the first degree: class b felony, (a) A person is guilty of manslaughter in the first degree when: ... (3) under circumstances evincing an extreme indifference to human life, he recklessly engages in conduct whieh creates a grave risk of death to another person, and thereby causes the death of another person.” (Emphasis added.)
The defendant argues that eases such as
State
v.
Tomassi,
One of the defendant’s claims of error, that the trial court erred in instructing the jury that the defendant’s “inaction” could constitute “conduct” within § 53a-55 (a) (3), ean be dismissed with little discussion. We approved the principle long ago that a cause of death suflicient to establish criminal liability could be an act, or
omission to
act.
State
v.
Tomassi,
For example, in
People
v.
Stamp, 2
Cal. App. 3d 203,
The court instructed the jury as to the concept of proximate cause as follows:
“In legal terms, proximate cause of death is that eause whieh, in natural and continuous sequence, unbroken by any efficient intervening cause, produces the death, and without whieh the death would not have occurred. It is the efficient cause of death, the one that necessarily sets in operation the factors that accomplish the death. Note particularly in this context that even though there may have been some causative influence from intervening factors or events, such as in this case Mr. Murdock’s preexisting heart condition, it is yet sufficient to proximate cause and to the legal responsibility of the defendant thereupon that the defendant’s conduct set in motion the chain of events whieh ultimately produced Mr. Murdock’s death as their sufficiently direct result or consequence. If the defendant’s conduct in his relations with Mr. Murdock inflicted upon the latter physical or emotional injury or stress or trauma whieh was in this sense the proximate cause of his death, then the defendant's conduct, under the circumstances, caused his death and satisfied this element of the law or charge upon this offense, even though such physical or emotional stress or trauma were not the only cause of Mr. Murdock’s death, and although Mr. Murdock had already been enfeebled by poor physical condition or severe heart disease, and even though it is probable that a person in sound physical condition would not have succumbed from the effects of the defendant’s conduct upon him, and even though it is probable that the defendant’s conduct only hastened Mr. Murdock’s death, or that he would have died soon thereafter from another eause or causes.”
The defendant in his brief does not seriously pursue a claim that there was insufficient evidence to sustain the robbery and unlawful restraint counts. We thus limit our discussion to the evidence supporting the manslaughter count.
