There's no way that a 50 something year old dude that gets on stage and dances for a living and that has had eighteen bajillion plastic surgeries would have a pre-existing heart condition.
Actually, that's not true; like myself, Michael Jackson had lupus. In older lupus patients, the risk of heart attack and cardiovascular issues is quite high. You can read more about it
here. Also worth mentioning, Jackson's health has been in shambles for awhile, and there are a lot of documented accounts of people involved in his O2 rehearsals commenting on how sick and listless he seemed. He even canceled a few performance dates awhile back because of his health issues. Jackson tended to remain very private about the status of his health, so I'm sure there was a lot going on that we, the public, didn't know about.
He may have died from a drug induced heart attack, but that doesn't necessarily mean he was taking drugs recreationally, or even willingly. His doctor is getting questioned over and over and over again by cops even though they took his statement already. They think it sounds like foul play.
One distinction to make here.
Michael Jackson was in
cardiac arrest, which differs from a heart attack. A heart attack is usually related to a circulatory problem, like clogged arteries, which blocks the supply of oxygen rich blood to the heart; a cardiac arrest is caused from an electrical issue within the heart (ventricular fibrillation). Cardiac arrest tends to be more fatal, unfortunately.
There's a really good explanation of it
here. The doctor in the video explains it a thousand times better than I ever could! Last I read on the case, the police said they don't consider Dr. Murray, MJ's personal physician, a suspect in any way. They say he's been cooperating with police and answering their questions. It's all up to toxicology reports now... they know he had a Demerol injection shortly before he died, which is known to cause cardiac arrest, so that very well could be the cause! I just hope his family finds the answers they need.
I think Jackson's death is getting more notoriety for a few reasons: first of all, Jackson has had a large, world-wide cultural impact, while Farrah's influence is quite a bit smaller. Secondly, the mystery surrounding Jackson's death and the investigation going on currently will give it more press. Fortunately, Farrah cause of death was completely known when she passed. Thirdly, a lot of things are up in the air because of the sudden nature of Jackson's death, like the custody of his children and his debts. Both deaths were extremely tragic and very, very sad, but I can see why Michael is getting more publicity.