First, heart attacks don't instantly happen to people because they're overweight. It increases the risk, but it still needs to have a cause. One cause could be a stressful situation that causes an increase in heart rate, like being hit by a car.
Second, if I shoot you, and then you die of blood loss from the wound, that still means I murdered you. Similarly, if you run over someone with a car, and then they die of a heart attack, either from the stress of the situation or the damage they've sustained, that means you murdered them.
And, third, I find it telling that the only source I could find that tells your version of the story also said that the truthful version was a result of a Judeo-Bolshevist conspiracy to control the media and lay appropriate blame on those who murder people.