Hi there lukin4antsirs (like the username!),
If you have heart problems and have had even a few possible sleep apnea symptoms, it's worth being tested, if only to rule out sleep apnea.
There must have been some concern for you have been ordered your sleep study years ago. It might be worth being restudied, especially considering your heart problems.
You may or may not have sleep apnea, but it's important to know. Untreated sleep apnea affects the heart and causes a host of health issues. People with untreated sleep apnea are at a significantly higher risk to heart attacks and strokes. If you do have sleep apnea, treatment can help. If you don't have sleep apnea, the testing can help doctors to focus on other possible causes. You owe it to yourself to get tested.
And if you do go for another sleep study, give yourself a fighting chance. Do everything you can to be as sleepy as possible at night. Refrain from naps during the day before the sleep study, cut out the caffein. If you have trouble sleeping and really need a sleep aid, you might have your doctor prescribe a sleep aid temporarily. Take it with you to your sleep study, let the sleep tech know, and they may decide you could take it, if necessary, in order for you to sleep enough for the sleep study. The preference is to not use a sleep aid, but sometimes it is needed to be tested.