Maya, I'm one of the "46 million" and growing (and I'm sure I wasn't even counted) who don't have health insurance. I often say that not having it is my biggest health risk.
I've investigated things recently and here's what I've found. My heart disease would have a minimum 2 year exclusion, even after that the coverage could be limited, and my insurance premiums in the meantime would be over $1000 a month. That could be extended or raised at any time. Because I need medical care now, including my heart, I have found that my best (only) option is to go through the teaching hospital, however I have been trying to get a referral approved to see a cardio since January, apparently without regard for my history of rheumatic heart disease with 3 damaged valves and now symptomatic. This is why I have decided to go see a cardio at Cleveland Clinic. Before it occurred to me to do that, I found that in my area NO cardio will see me at all without health insurance. CC was the one exception to this, so even though it's about 2 hours away, that's where I'm going.
I have a friend who had a heart attack 5 years ago with no recurrences of any kind. She is a cardio nurse at a local hospital. First, they tried to terminate her insurance (unsuccessfully) and then they raised her rate to $880 a month and still climbing. During all that time she has still been employed at the same hospital - which she feels she can't leave because if she changed employers, the new insuror would throw in a 2 year exclusion and raise her rate even more.
I believe that if you have insurance and lose your job, there is something called Cobra, which is a transitional policy that you pay for individually until you obtain other insurance. However, if you miss a payment (remember, you're not working!) you are immediately cancelled. If this happens, then you are right where I am, though mine is for different reasons.
From my experience, I would urge everyone who is now insured to do everything possible to keep your insurance. I believe that my prognosis and treatment options are extremely limited compared to what they would be if I had insurance.
In emergencies, ER's do have to treat you (insured or not) - only until you are stable. During the last decade 14% of all ER's in the US have closed down - for cost cutting measures. See where all this is going?
If you have health insurance - do your best to hang on to it! There are no good ways around this problem.