(CNN)Caution: This story contains spoilers about the latest episode of NBC’s “This Is Us.”
“I don’t understand why he died,” Kate Pearson says sadly to her mother, Rebecca, as they struggle with their grief in the middle of the night during Tuesday’s episode of the NBC show “This is Us.”
It’s not just Kate who can’t fathom how her father, Jack, died during Sunday’s Super Bowl episode. For die-hard fans, Jack’s sudden death after surviving the flames of their burning home — while rescuing not only his daughter’s dog but the family’s precious photo books — is downright bewildering.
Despite Jack’s coughing and weak voice, the show made us think that all was well after the fire. After all, an emergency room doctor didn’t rush him off for tests or put him on a respirator. But as Jack’s wife, Rebecca, was making calls to arrange a hotel room, a “code blue” erupted behind her. Soon, viewers learned that Jack had died of cardiac arrest, triggered by the smoke.
“One of the complications of smoke inhalation is that it puts terrible stress on the lungs and therefore the heart,” the emergency room doctor told Rebecca in the Sunday episode. “Your husband went into cardiac arrest. It was catastrophic, and I’m afraid we’ve lost him.”
Was that just creative license, or can such an attack be triggered by smoke?
“I think that it’s completely possible that this type of situation can cause cardiac arrest, for multiple different reasons,” said Dr. Kevin Campbell, a North Carolina cardiologist who specializes in the diagnosis and treatment of heart rhythm disorders.
One reason: Smoke inhalation puts stress on the heart by reducing the amount of oxygen to the heart muscle.
“When that happens, you can have a dangerous arrhythmia, or abnormal heart rhythm, similar to as if you had a blockage in the heart artery,” Campbell said. “So if you are having trouble breathing and you can’t get oxygen, you can have a cardiac arrest with that.”
Smoke from a house fire contains many dangerous chemicals, such as sulfur dioxide, benzene, acid gases, cyanide and carbon monoxide, that can irritate the airways and make it difficult to breathe. Inhaling carbon monoxide also reduces the oxygen supply to the body, including the heart, starving the heart muscle of the fuel it needs to function.
Another reason for Jack’s “widowmaker,” defined as a critical blockage of the main artery down the front of the heart, might be underlying cardiovascular disease. A “widowmaker” gets its name because it’s nearly always fatal if not addressed within minutes.
“If you’re a person with underlying heart disease,” Campbell said, “then the rush of adrenaline and all the hormones that are released into the body for fight or flight can put extra stress on the heart.”
Cardiologist Dr. Arthur Agatston, creator of the heart-healthy South Beach Diet, agrees.
“In this case, there was tremendous physical stress from Jack lowering his wife and kids down from the house during the rescue,” Agatston said. “That would be exacerbated by the smoke inhalation, decreasing the amount of oxygen that can get to the blood. And then there’s all the emotional stress as well, and all that produces a lot of adrenaline that can lead to acutely clogging up your arteries.”
The show has never mentioned that Jack had underlying heart disease or even high blood pressure. But at his age, which is in his early 50’s, Agatston said, there was probably some plaque buildup in his arteries.
“The cholesterol ‘pimples’ that build up in the wall of blood vessels are like little ticking time bombs,” he said. “They can literally pop like a pimple does, and what they extrude into the bloodstream causes a blood clot. Usually, the clot heals over with calcium and scar tissue, and you don’t feel anything.”
But when there is a lot of stress, like that Jack faced, the clot can become bigger, Agatston said, and even “wax and wane over minutes, hours or even days or a week or two.”
“Presumably, Jack had the pop and the resulting clot during the fire, but it didn’t occlude the vessel,” he explained. “But something happened when he was in the hospital, and all of a sudden, the clot blocked the main artery and caused the heart attack.
“Jack may have even thought ‘Oh, my God, I came close to dying and losing my family’ and that type of emotional stress increases adrenaline, which makes these clots bigger and more likely to block a vessel,” Agatston added.
Another possible contributing factor: Jack is a recovering alcoholic.
“That certainly puts your heart at risk,” Campbell said. “If you’re abusing alcohol, you can have a very, very weakened heart muscle, and that can precipitate cardiac arrest or make it more likely.”
Agatston agreed: “Drinking alcohol can cause an abnormal heart rhythm and also can cause high blood pressure, which is a risk factor.”
One thing that isn’t realistic in the show, Agatston said: the lack of treatment Jack received.
“A code blue like that would go on for much longer than two to three minutes,” he said. “It can go on for 20 to 30 minutes or even longer before you stop CPR.”
In the real world, Agatston added, doctors would also suggest that Jack’s children be screened for potential heart disease with a heart scan and a look at their calcium score.
“When someone dies that young from a heart attack, the kids should definitely be screened,” he said. “You can see plaque in the arteries years before a heart attack. If Jack had had that, his heart attack could have been prevented.”
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