stress-induced myocardial ischemia

[Robert__0]

  
  My father, a 74-year old man who had suffered for several years with angina,
  died of a heart attack suddenly and without a sound while driving on the high
  way with my mother. An autopsy was performed, showing vessel blockages
   of 75% and 25%. When I asked my father's physician why he had taken the
    attack at that moment, when he was under no physical stress at all, I was
   informed that the actual event could have happened several hours earlier,
  and that it's ultimate effect took place on the highway. This was the first I had
   ever heard of "silent heart attacks". I recalled that several hours prior to his
   death, I saw my mother crying. She explained that my father had taken a
   telephone call which was very stressful to him, and (in my mother's own
   words) : "he just turned gray right in front of me". She left so that he would
   not see how worried she was. My first question is: What was actually
   ocurring physiologically to my father when he "turned gray"? And secondly:
   What is the likelihood that this event contributed to my father's death, or
   perhaps even caused it? A clinician with considerable experience in this
  type of situation told me that the grayness was the result of a reduction in
  ejection fraction and that, while an absolute answer cannot be given, in light
  of the facts my father most likely died due to a stress-induced myocardial
  infarction. Is he correct?

[CCF Cardio MD - MTR]

Dear Robert, you ask a difficult question because I will be speculating on events I did not witness. However, I want to express my sympathy to you and your family for your loss.  Nonetheless, I'll try to provide some information for you.  Your father suffered from sudden cardiac death (SCD).  SCD occurs most commonly from an arrhythmia (an abnormal fast or slow heart rhythm) but can also be caused by a sudden decrease in cardiac output from abrupt myocardial ischemia / heart attack.  An autopsy cannot differentiate these causes because the heart is no longer electrically active and because the changes that occur in the heart muscle after a heart attack take > 24 hrs. to occur.  After SCD, there has not been enough time for changes from a heart attack to occur to be reliably identified with an autopsy.  It's quite possible that your father was having unstable ischemic angina prior to his death and that an unstable coronary plaque was the cause of the symptoms you describe.  Whether his ejection fraction suddenly dropped when he turned gray is hard to know, but I think he may have developed angina which could make his complexion appear gray to an observer.  There is no specific physiologic explanation for such an episode other than during an episode of pain from any cause, the amount of blood flow to the face may decrease.  I can't say whether this event caused  your father's death, but it may have contributed to it.  He could have had a heart attack that caused an arrhythmia, but there's no way to be sure.  Overall, I suspect that he had a sudden arrhythmia that could not have been predicted and could only have been treated if he happened to be at a medical facility with a defibrillator readily available.
I hope you find this information useful.  Information provided in the heart forum is for general purposes only.  Only your physician can provide specific diagnoses and therapies. Please feel free to write back with additional questions.