I had a friend whose father died shortly after eating Thanksgiving dinner... I read up on it, and apparently it's pretty common. Here's one quote:

<< [A] study of 1,986 heart attack patients presented at a meeting of the American Heart Association in 2000 suggested that an unusually large meal quadrupled the chance of having a heart attack within the next two hours.

After a large meal (a Thanksgiving feast can easily exceed 4,000 calories), cardiac output of blood is increased and diverted to the intestinal circulation to aid digestion, which can take as long as six hours, leaving other organs, including the heart and brain, relatively deprived. The work involved in all this shunting around of blood might be the equivalent of vigorous sex or moderate exercise.

But that's not all. An increase in insulin, triggered by the carbohydrate content of the meal, can compound the situation by preventing normal relaxation of the coronary arteries. Triglyceride elevation, from the fats and carbs, can impair the function of the inner lining of the coronary arteries and cause those vessels to become less elastic and acutely inflamed. Increases in inflammatory markers such as C-reactive protein have been noted following a large, high-fat meal. And the rise in blood pressure that usually occurs after eating such a meal can cause those inflamed patches to rupture, which in turn can lead to blockages and heart attacks. >>

http://www.washingtonpost.com/wp-dyn/content/article/2010/11/22/AR2010112204836.html

Please be careful with your family and loved ones!