In Feb. I Woke Up At 3:30 Am With Pressure

In Feb. I woke up at 3:30 am with pressure and extreme discomfort under the sternum, which led to diagnosing a 60% plus, occluded heart artery. Had a stent put in during March. Cardiologist has now released me to be seen again in 1yr. Apparently I have another artery that is 20 some % blocked, but he said that he doesn't expect it to give me any trouble. The last 2 nites I have had the same symptoms in the nite 2 to 6 hrs after retiring. They include pain and pressure under the sternum which wakes me up, breaking out into a cold sweat, nausea, & having to have an immediate bowel movement. I'm afraid to get up without help, because the first time I had a Vasovagal incident before making it to the bathroom. Once I passed out the pain subsided until a couple of hours later in the ER. With the recent episodes there has been quite a bit of gas coming up once I sit up. I am very tired during the day and my stomach is not feeling very good. No vomiting or diahrrea. I planning on calling the Cardiologist, but want to know if you think it's more likely to be GERD, rather than heart symptoms. Or is there some other likihood?